| JP6449117 | Intermediate medium type gas vaporizer |
| JP2001116196 | LIQUEFIED GAS VAPORIZING DEVICE |
HIROSE KENJI (JP)
NISHI YASUHARU (JP)
TOMITA SHINJI (JP)
| EP1391670B1 | 2006-10-04 | |||
| US20090129941A1 | 2009-05-21 | |||
| JP2013046890A | 2013-03-07 | |||
| JP2002181444A | 2002-06-26 | |||
| GB1539077A | 1979-01-24 | |||
| JPH07218121A | 1995-08-18 | |||
| JP2003074793A | 2003-03-12 | |||
| JPS51101219A | 1976-09-07 |
| Claims 1 . A liquefied gas supply spare system, comprising: a storage tank that stores liquefied gas; 5 a liquefied gas pump that feeds the liquefied gas to downstream from the storage tank; an evaporator that causes the liquefied gas fed from the liquefied gas pump to transition in state into gas at a first temperature lower than a surrounding environment temperature; 0 a heat exchange unit that increases a temperature of the gas at the first temperature to a second temperature higher than the first temperature, by a heating medium; a spare gas supply pipe that feeds the gas to a main pipe, downstream of the heat exchange unit; 5 a pressure gauge that measures an inner pressure in the main pipe or the spare gas supply pipe; a generator that supplies power to the liquefied gas pump; and a generator control unit that controls the generator to operate the generator when the pressure measured by the pressure gauge drops to or o below a threshold value. 2. The liquefied gas supply spare system according to claim 1 , further comprising: a heating unit that is disposed at a subsequent stage of the heat 5 exchange unit, and increases a temperature of gas at the second temperature which is generated in the heat exchange unit to a third temperature higher than the second temperature by an electric heater, wherein the generator supplies power to the electric heater and/or the liquefied gas pump. 3. The liquefied gas supply spare system according to claim 1 , further comprising: a heating unit that is disposed at a subsequent stage of the heat exchange unit, and increases a temperature of gas at the second temperature which is generated in the heat exchange unit to a third temperature higher than the second temperature, by an electric heater, wherein when the second temperature is a temperature higher than an impurity removing treatment temperature (T) in a chemical adsorption type impurity removal device, the generator supplies power to the liquefied gas pump, and stops or does not supply power to the electric heater, and when the second temperature is lower than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device, and the third temperature is a temperature higher than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device, the generator supplies power to the electric heater and the liquefied gas pump. 4. The liquefied gas supply spare system according to any one of claims 1 to 3, wherein the heating medium is a heating medium that is generated in the generator. 5. The liquefied gas supply spare system according to claim 4, further comprising: a heating medium circulation passage for circulating the heating medium to the heat exchange unit and the generator, wherein the heating medium is a cooling fluid that cools the generator. 6. The liquefied gas supply spare system according to any one of claim 1 to claim 5, wherein the heat exchange unit is disposed in a downstream side tube, of tubes configuring the evaporator. 7. The liquefied gas supply spare system according to any one of claim 1 to claim 6, wherein the heat exchange unit includes a heating medium passage having the heating medium inlet that receives the heating medium, and a heating medium outlet that discharges the received heating medium, and a gas passage in which gas to be heated flows, and the heating medium inlet is disposed at a downstream side of the gas passage, and the heating medium outlet is disposed at an upstream side of the gas passage. 8. The liquefied gas supply spare system according to claim 2 or 3, comprising: a first thermometer that measures a temperature of gas in the spare gas supply pipe, or measures a temperature of the spare gas supply pipe; and an electric heater control unit that controls the electric heater so that the temperature measured by the first thermometer becomes the third temperature. 9. The liquefied gas supply spare system according to claim 8, further comprising: a second thermometer that measures a temperature of gas in the gas to be heated introduction pipe, or measures a temperature of the gas to be heated introduction pipe, wherein the electric heater control unit controls the electric heater so that the temperature measured by the first thermometer becomes the third temperature, based on the respective temperatures measured by the second thermometer and the first thermometer. 10. The liquefied gas supply spare system according to claim 9, further comprising: a third thermometer that measures a temperature of gas in the evaporation gas supply pipe, or measures the temperature of the gas to be heated introduction pipe, wherein the electric heater control unit controls the electric heater so that the temperature measured by the first thermometer becomes the third temperature, based on any one or two or more of the respective temperatures measured by the third thermometer, the second thermometer and the first thermometer. 1 1 . The liquefied gas supply spare system according to claim 10, further comprising: a flow meter that is disposed in the main pipe or the spare gas supply pipe, and measures a flow rate in the main pipe or the spare gas supply pipe, wherein the electric heater control unit controls the electric heater so that the temperature measured by the first thermometer becomes the third temperature, based on any one or two or more of the respective temperatures measured by the third thermometer, the second thermometer, and the first thermometer, and the flow rate measured by the flow meter. 12. A liquid gas supply system with a backup, comprising: an air compression unit that compresses source air; a purification unit that removes impurities from compressed source air obtained in the air compression unit; a main heat exchange unit that cools compressed source air purified in the purification unit; a rectification unit that separates the compressed source air cooled in the main heat exchange unit into a nitrogen and an oxygen; and the liquefied gas supply spare system according to any one of claim 1 to claim 1 1 . 13. A liquefied gas spare supply method, comprising: a first detection step of detecting that supply of gas is interrupted or stopped from main supply; a power supply step of supplying power to a liquefaction pump by using a generator, based on a detection result of the first detection step; a first temperature increasing step of vaporizing liquefied gas fed from a storage tank by the liquefied gas pump to a first temperature lower than a surrounding environment temperature to change the liquefied gas to gas, by using an evaporator; a second temperature increasing step of increasing a temperature of the gas at the first temperature which is vaporized in the first temperature increasing step to a second temperature higher than the first temperature, by using a heat exchange unit; and a backup supply step of feeding the gas increased in temperature to the second temperature in the second temperature increasing step, to a main supply side. 14. A liquefied gas spare supply method, comprising: a first detection step of detecting that supply of gas is interrupted or stopped from main supply; a power supply step of supplying power to a liquefied gas pump and/or an electric heater by using a generator, based on a detection result of the first detection step; a first temperature increasing step of vaporizing liquefied gas fed from a storage tank by the liquefied gas pump to a first temperature lower than a surrounding environment temperature to change the liquefied gas to gas, by using an evaporator; a second temperature increasing step of increasing a temperature of the gas at the first temperature which is vaporized in the first temperature increasing step to a second temperature higher than the first temperature by using a heat exchange unit; a third temperature increasing step of increasing a temperature of the gas increased in temperature to the second temperature in the second temperature increasing step to a third temperature higher than the second temperature in a heating unit using an electric heater; and a backup supply step of feeding the gas increased in temperature to the third temperature in the third temperature increasing step to a main supply side. 15. A liquefied gas spare supply method according to claim 14, further comprising: a step of the generator supplying power to the liquefied gas pump and stopping or not supplying power to the electric heater, when the second temperature is a temperature higher than an impurity removing treatment temperature (T) in a chemical adsorption type impurity removal device, and the generator supplying power to the electric heater and the liquefied gas pump, when the second temperature is lower than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device, and the third temperature is a temperature higher than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device. 1 6. A gas supply method with a backup that is a method for supplying gas by vaporizing liquefied gas by a main evaporator, comprising: a step of supplying gas obtained by vaporizing liquefied gas in an evaporator from a gas production unit to a downstream process through a main pipe; an impurity removing step of removing impurities in the gas in an impurity removal unit disposed in the main pipe; and a step of the liquefied gas spare supply method according to any one of claims 13 to 15, which is a step of supplying similar gas to the gas, through a spare gas supply pipe that joins the main pipe at an upstream side from the impurity removal unit. |
SUPPLY METHOD
Description
Technical Field
The present invention relates to a liquefied gas supply spare system and a liquefied gas spare supply method in liquefied gas supply. As liquefied gas, there are cited, for example, a liquid nitrogen, a liquid oxygen (for example, an ultra-high purity oxygen), liquefied natural gas (for example, a high-purity methane) and the like.
Background Art
Backup equipment is often installed in facilities that continuously or intermittently produce gas and supply the produced gas. This is to continuously supply the gas even when the manufacturing facilities stop.
For example, when nitrogen gas produced by an air separation device is continuously supplied to the use destination, backup equipment is placed at the air separation device in order to cope with the case where the supply stops due to the loss of power supply (Patent Literature 1 ).
When nitrogen gas with high purity is supplied at a normal time, supply of nitrogen gas with high purity is also required at a time of actuation of the backup equipment. In order to produce backup nitrogen with high purity, it is necessary to increase pressure of a stored liquid nitrogen with a pump, evaporate the nitrogen in an atmospheric evaporator, and thereafter to remove impurities by a chemical adsorbent.
[0004] In order to remove impurities by a chemical adsorbent, the gas which is introduced into the chemical adsorbent must have a certain temperature or more. In a warm environment, if an atmospheric evaporator is used, the evaporated gas is heated to a temperature required for chemical adsorption or more. However, in cold districts, a sufficient amount of heat cannot be obtained from the atmosphere, and the gas evaporated by the atmospheric evaporator is introduced into a downstream chemical adsorbent, while a temperature of the gas remaining at a temperature lower than the
temperature required for chemical adsorption.
Therefore, the gas evaporated by the evaporator is further heated to a required temperature by using an electric heater. When the power supply is lost, the power supply of the electric heater is supplied from an emergency power supply (for example, a diesel power generator). Further, the emergency power supply is also used as a power supply of the above described pump.
In the conventional art, all of the heat amount required for heating from the temperature reachable by the atmospheric evaporator to the temperature required for chemical adsorption has been supplied by the electric heater. Consequently, the power consumption amount is large, and it is also necessary to make the facility for supplying the power supply large.
As the method for evaporating liquefied gas and heating the liquefied gas to a desired temperature by a relatively small power consumption amount, there is proposed a method for supplying combustion heat that is obtained by combusting liquefied natural gas to a heating unit (Patent Literature 2). However, the method has a problem of consuming a part of the liquefied gas (liquefied natural gas) which is produced as a product, by combustion.
As another method for evaporating and heating liquefied gas, there is also proposed a method that uses exhaust heat of a diesel power generator and coldness of liquefied gas (Patent Literature 3). However, the configuration of the method is complicated, a starting process is also complicated, and it takes time to start up, so that it is difficult to cope timely with emergency such as losing power supply although the method is suitable for a steady operation.
Citation List
Patent Literature
[Patent Literature 1 ] Japanese Patent Laid-Open No. 7-218121
[Patent Literature 2] Japanese Patent Laid-Open No. 2003-74793
[Patent Literature 3] Japanese Patent Laid-Open No. 51 -101219
Summary of Invention
Technical Problem
The present invention has an object to provide a liquefied gas supply spare system and a liquefied gas spare supply method that exclude the above described disadvantage, and continuously carry out supply of liquefied gas with less power consumption.
Solution to Problem
(Invention 1 )
A liquefied gas supply spare system according to the present invention includes
a storage tank that stores liquefied gas,
a liquefied gas pump that feeds the liquefied gas to downstream from the storage tank,
an evaporator that causes the liquefied gas fed from the liquefied gas pump to transition in state to gas at a first temperature lower than a surrounding environment temperature, a heat exchange unit that increases a temperature of the gas at the first temperature to a second temperature higher than the first temperature, by a heating medium,
a spare gas supply pipe that feeds the gas to a main pipe, downstream of the heat exchange unit,
a pressure gauge that measures an inner pressure in the main pipe or the spare gas supply pipe,
a generator that supplies power to the liquefied gas pump, and a generator control unit that controls the generator to operate the generator when the pressure measured by the pressure gauge drops to or below a threshold value.
In the liquefied gas supply spare system according to the present invention, supply of the liquefied gas can be continuously carried out even when the pressure of the gas which is supplied by the main pipe is reduced for the reason of loss of power supply, an insufficient storage amount of liquefied gas which is supplied by the main pipe and the like, for example.
That is, when the measurement value of the pressure gauge becomes the threshold value or less, the generator is operated and power is supplied to the liquefied gas pump, and the heating medium is supplied to the heat exchange unit, whereby temperature increase is changed to a temperature increase by the evaporator and the heat exchange unit from the conventional temperature increase by the evaporator and the electric heater, and the power supply amount from the generator can be reduced as compared with the conventional system.
In the present invention, the surrounding environment temperature may be the temperature lower than the impurity removing treatment temperature in the chemical adsorption type impurity removal device that removes impurities in the gas that is obtained by the liquefied gas being gasified in an atmospheric type evaporator, for example, and may be any one of 10°C or less, 5°C or less, 0°C or less, and -5°C or less.
In the above described invention, the "second temperature" is preferably a temperature higher than an impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device, is more preferably higher than the impurity removing treatment temperature (T) by 2°C or more, and is much more preferably higher than the impurity removing treatment temperature (T) by 4°C or more. The "second temperature" is preferably set in accordance with a distance of the pipe from the heating unit to the impurity removal unit and heat insulation performance of the pipe.
One embodiment of the present invention further includes a heating unit that is disposed at a subsequent stage of the heat exchange unit, and increases a temperature of gas at the second temperature which is generated in the heat exchange unit to a third temperature higher than the second temperature by an electric heater,
wherein the generator may be configured to supply power to the electric heater and/or the liquefied gas pump.
In the case of the above described configuration, the "third
temperature" is preferably a temperature higher than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device, more preferably higher than the impurity removing treatment temperature (T) by 2°C or more, and is much more preferably higher than the impurity removing treatment temperature (T) by 4°C or more. The "third temperature" is preferably set in accordance with the distance of the pipe from the heating unit to the impurity removal unit, and the heat insulation performance of the pipe. According to the configuration, when the measurement value of the pressure gauge becomes the threshold value or less, the generator is operated, power is supplied to the liquefied gas pump and/or the electric heater, and the heating medium is supplied to the heat exchange unit, whereby a temperature increase by the three elements (devices) can be performed from the conventional configuration in which the temperature increase is performed by the two elements (devices), and the power supply amount from the generator can be reduced.
Further, one embodiment of the present invention further includes a heating unit that is disposed at a subsequent stage of the heat exchange unit, and increases a temperature of gas at the second temperature which is generated in the heat exchange unit to a third temperature higher than the second temperature, by an electric heater, and
the generator may be configured to supply power to the liquefied gas pump, and stop or not to supply power to the electric heater when the second temperature is a temperature higher than an impurity removing treatment temperature (T) in a chemical adsorption type impurity removal device, and the generator may be configured to supply power to the electric heater and the liquefied gas pump when the second temperature is lower than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device, and the third temperature is a temperature higher than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device.
According to the configuration, when the second temperature is a temperature higher than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device, the generator supplies power to only the liquefied gas pump and does not supply power to the electric heater, and when the second temperature is lower than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device, and the third temperature is a temperature higher than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device, the generator supplies power to the electric heater and the liquefied gas pump, whereby even when the system includes the electric heater, use of the electric heater can be properly controlled.
In the above described configuration, a first thermometer that measures the second temperature of the gas of the heat exchanger after the generator supplies power to the electric heater and the liquefied gas pump, or only the liquefied gas pump, and a second thermometer that measures the third temperature of the gas at the subsequent stage of the heating unit may be included.
The chemical adsorption type impurity removal device may be installed in the main pipe, or may be installed in the spare gas supply pipe.
In the present invention, the evaporator and the heat exchange unit may be configured as separate bodies.
In the present invention, the heat exchange unit may be an exhaust heat recovery unit.
In the present invention, an evaporation gas supply pipe for feeding gas to the heat exchange unit from the evaporator, and a gas to be heated introduction pipe for feeding gas to the heating unit from the heat exchange unit may be included.
In the present invention, the evaporator and the heat exchanger may be integrally configured.
In the present invention, the heat exchange unit may be disposed in a downstream side pipe configuring a part of the evaporator.
In the present invention, the storage tank that stores liquefied gas is a storage tank for storing liquefied gas such as a liquid nitrogen, a liquid oxygen or liquefied natural gas. Only one storage tank may be adopted, or a plurality of storage tanks may be adopted. The storage tank may be installed in a liquefied gas production facility, or may be independent from the liquefied gas production facility, and the storage tank may store liquefied gas which is produced at a remote place.
In the present invention, the evaporator may be of an air heating type. In the present invention, the heating medium of the heat exchange unit may be gaseous, or may be liquid. The temperature of the heating medium is a temperature higher than the first temperature.
[0018] In the present invention, the pressure gauge may measure an inner pressure of the main pipe, or may measure an inner pressure of the spare gas supply pipe at an upstream side of a point where spare gas joins the main pipe. When the impurity removal unit is provided in the main pipe or the spare gas supply pipe, the pressure gauge may be provided at a previous stage of the impurity removal unit or may be provided at a subsequent stage.
When the pressure gauge is disposed in the spare gas supply pipe, the control valve is disposed at a storage tank side from the pressure gauge, and may be controlled so that the control valve is closed at a normal operation time, and the control valve is opened at a backup operation time.
When the pressure gauge is disposed in the main pipe, the control valve is disposed in the spare gas supply pipe, and may be controlled so that the control valve is closed at the normal operation time, and the control valve is opened at the backup operation time.
In the present invention, the generator may be a diesel generator. The generator may supply power to both of the electric heater and the liquefied gas pump, but also can supply power to only either one of the electric heater or the liquefied gas pump. In the present invention, the generator is operated when the pressure measured by the pressure gauge drops to a threshold value or less, and the threshold value is a value lower than a supply pressure (a normal time supply pressure) at a time of supplying vaporized liquefied gas by the main pipe, and can be set in advance at a value of 50% or less of the normal time supply pressure, for example.
(Invention 2)
In the liquefied gas supply spare system according to the present invention, the heating medium can be a heating medium that is generated in the generator.
In the present invention, the heating medium that is generated in the generator may be exhaust heat that is generated by an temperature increase of the generator body following operation of the generator, or may be cooling water that is used to cool the generator. Here, a temperature of the exhaust heat or the cooling water is the second temperature or more.
In the present invention, the heating medium may be released into atmosphere after giving heat to the vaporized liquefied gas, may be released after predetermined treatment, or may be recovered. The aforementioned predetermined treatment may be treatment for reducing the temperature of the heating medium to a desired temperature set in advance or less, for example, or the heating medium may be released without the predetermined treatment.
Conventionally, gas has to be heated to a predetermined temperature to remove impurities in the liquefied gas that is evaporated in the evaporator, but heating by air is insufficient in cold districts. Therefore, the liquefied gas after evaporation has to be heated by supplying power to the electric heater by the generator. Meanwhile, the heat amount generated with drive of the generator is released to outside as the cooling water or exhaust heat of the generator. According to the present invention, the amount of heat generated with drive of the generator is effectively used in heating of the liquefied gas which is vaporized in the evaporator. Therefore, the power which the generator supplies to the electric heater decreases, and liquefied gas spare supply can be performed with a simple configuration with less power consumption.
(Invention 3)
The liquefied gas supply spare system according to the present invention can further include a heating medium circulation passage for circulating the heating medium to the heat exchange unit and the generator.
In the present invention, after the heating medium generated in the generator is used as the heating medium in the heat exchange unit, the heating medium may be released to outside of the heat exchange unit, but may be circulated to the generator by the heating medium circulation passage. The heating medium which is returned to the generator by the heating medium circulation passage may be used in cooling of the generator. The heating medium which is circulated by the heating medium circulation passage may be gaseous, or may be liquid such as cooling water, or other refrigerant liquids, for example.
In the present invention, by providing the heating medium circulation passage, the heating medium with the temperature reduced in the heat exchange unit also can be used as the heating medium that cools the generator, which is efficient. Further, even when high-temperature exhaust gas or cooling water cannot be released to around the generator, the heating medium is not released if the heating medium is circulated by the heating medium circulation passage and used, so that it is not necessary to release the heating medium after reducing the temperature to a fixed temperature or less. (Invention 4)
In the liquefied gas supply spare system according to the present invention, the heat exchange unit can be disposed in a downstream side tube, of tubes configuring the evaporator.
In the present invention, the liquefied gas in a liquid state flows into the evaporator upstream side tube, and is gradually vaporized toward the evaporator downstream side tube. Therefore, the heat exchange unit is disposed in the downstream side pipe configuring a part of the evaporator, and is configured so that the heating medium and the gas in the downstream side pipe can perform heat exchange.
In the present invention, an apparatus configuration is simplified by integrating the evaporator and the heat exchange unit, and a foot print in which the apparatus is disposed can be made small.
(Invention 5)
In the liquefied gas supply spare system according to the present invention, the heat exchange unit includes a heating medium passage having the heating medium inlet that receives the heating medium, and a heating medium outlet that discharges the received heating medium, and a gas passage in which gas (gas which is fed from the evaporator, or gas at the evaporator downstream side) to be heated flows, and
the heating medium inlet may be disposed at a downstream side of the gas passage, and the heating medium outlet may be disposed at an upstream side of the gas passage.
In the present invention, the heat exchange unit has an upstream side portion where vaporized liquefied gas is at a relatively low temperature immediately after being introduced into the heat exchange unit, and a downstream side portion where the vaporized liquefied gas which is heated in the heat exchange unit is at a relatively high temperature. In the present invention, the heating medium may be supplied to the entire heat exchange unit, but may be supplied to the downstream portion. In order that the heating medium contacts an outside of the pipe where the vaporized liquefied gas passes, the heat exchange unit may have blowing means that blows the heating medium to the outside of the pipe.
In the present invention, the heat exchange unit is not specially limited, and may be a known shape. The heat exchange unit may be a heat exchange unit of a countercurrent type structure that is a structure in which the heating medium flows to a low-temperature side which is a gas passage downstream side from a high-temperature side which is a gas passage upstream side. By the heat exchange unit of the countercurrent structure, heat exchange efficiency is further enhanced.
(Invention 6)
The liquefied gas supply spare system according to the present invention can include a first thermometer that measures a temperature of gas in the spare gas supply pipe, or measures a temperature of the spare gas supply pipe, and
an electric heater control unit that controls the electric heater so that the temperature measured by the first thermometer becomes the third temperature.
In the present invention, the thermometer is inserted into the spare gas supply pipe, and may measure the gas temperature in the spare gas supply pipe. Further, in the present invention, the thermometer may be pasted on an outside of the spare gas supply pipe, and may measure a pipe
temperature of the spare gas supply pipe.
In the present invention, the heating unit may have a multi-pipe type or a fin-type of electric heater. The electric heater control unit controls the electric heater, may perform ON/OFF control of a current which is supplied from the generator, or may perform feedback control based on the measured gas temperature, for example.
In the present invention, by controlling the electric heater based on the temperature of the spare gas supply pipe, liquefied gas (liquefied gas after vaporization) at a desired temperature set in advance can be supplied even when a change in surrounding environment temperature and a variation in liquefied gas supply amount take place. Further, the vaporized liquefied gas temperature can be controlled to a fixed temperature by further performing feedback control, so that power from the generator can be reduced.
(Invention 7)
The liquefied gas supply spare system according to the present invention further includes the second thermometer that measures a temperature of gas in the a gas to be heated introduction pipe, or measures a temperature of the gas to be heated introduction pipe, wherein the electric heater control unit can control the electric heater so that the temperature measured by the first thermometer becomes the third temperature, based on the respective temperatures measured by the second thermometer and the first thermometer.
In the present invention, the thermometer is inserted in the gas to be heated introduction pipe, and may measure the gas temperature in the gas to be heated introduction pipe. Further, in the present invention, the
temperature is pasted on the outside of the gas to be heated introduction pipe, and may measure the pipe temperature of the gas to be heated introduction pipe.
In the present invention, the temperature of the vaporized liquefied gas which flows in the gas to be heated introduction pipe varies in accordance with the change of the surrounding environment temperature, variation of the liquefied gas supply amount and the operation situation of the generator. Therefore, by measuring the temperature of the gas in the gas to be heated introduction pipe, or the temperature of the gas to be heated introduction pipe, and controlling the electric heater based on the measured temperature, the liquefied gas (the liquefied gas after vaporization) at a desired temperature set in advance can be supplied. Further, feed-forward control is enabled in addition to feedback control, the vaporized liquefied gas temperature can be controlled to a fixed temperature more, so that the power from the generator can be reduced.
(Invention 8)
The liquefied gas supply spare system according to the present invention further includes a third thermometer that measures a temperature of gas in the evaporation gas supply pipe, or measures the temperature of the gas to be heated introduction pipe,
wherein the electric heater control unit can control the electric heater so that the temperature measured by the first thermometer becomes the third temperature, based on either one or two or more of the respective
temperatures measured by the third thermometer, the second thermometer and the first thermometer.
In the present invention, the thermometer is inserted in the evaporation gas supply pipe, and may measure the gas temperature in the evaporation gas supply pipe. Further, in the present invention, the thermometer is pasted on the outside of the evaporation gas supply pipe, and may measure the pipe temperature of the evaporation gas supply pipe. The evaporator and the heat exchange unit are respectively independent from each other, and when they are connected by a pipe, the gas temperature in the pipe between the evaporator and the heat exchange unit, or a temperature of the pipe may be measured. When the evaporator and the heat exchange unit are configured integrally, the thermometer may be disposed in an upstream position of the integrated configuration.
In the present invention, the temperature of the vaporized liquefied gas which flows in the evaporation gas supply pipe varies in accordance with a change in surrounding environment temperature and a variation in liquefied gas supply amount. Therefore, the temperature of the gas in the
evaporation gas supply pipe or the temperature of the evaporation gas supply pipe is measured, and the electric heater is controlled based on the measured temperature, whereby the liquefied gas (the liquefied gas after vaporization) at a desired temperature which is set in advance can be supplied. Further, this enables each of feedback control and feed-forward control, or a combination thereof. Accordingly, the vaporized liquefied gas temperature can be controlled to a fixed temperature more, so that power from the generator can be reduced.
(Invention 9)
The liquefied gas supply spare system according to the present invention further includes a flow meter that is disposed in the main pipe or the spare gas supply pipe, and measures a flow rate in the main pipe or the spare gas supply pipe, wherein the electric heater control unit can control the electric heater so that the temperature measured by the first thermometer becomes the third temperature, based on either one or two or more of the respective temperatures measured by the third thermometer, the second thermometer, and the first thermometer, and the flow rate measured by the flow meter.
In the present invention, the flow meter may be of an orifice pressure differential type, or may be a mass flow meter.
In the present invention, when the amount of the vaporized liquefied gas which is supplied from the spare gas supply pipe increases, the power which is required by the electric heater also becomes large. Consequently, the electric heater is controlled based on the flow meter that measures the flow rate in the spare gas supply pipe, and one or two or more of the respective temperatures which are measured by the third thermometer, the second thermometer and the first thermometer, whereby the liquefied gas (the liquefied gas after vaporization) at the desired temperature set in advance can be supplied.
(Invention 10)
A liquid gas supply system with a backup according to the present invention can include
an air compression unit that compresses source air,
a purification unit that removes impurities from compressed source air obtained in the air compression unit,
a main heat exchange unit that cools compressed source air purified in the purification unit,
a rectification unit that separates the compressed source air cooled in the main heat exchange unit into a nitrogen and an oxygen, and
the liquefied gas supply spare system described above.
[0046] In the present invention, the kind of gas which is produced from the source air may be an oxygen, or a nitrogen, or both oxygen and nitrogen.
In the present invention, the purification unit that removes impurities from the compressed source air may have a function of removing impurities such as water from the compressed source air.
In the present invention, the main heat exchange unit may cause exhaust gas generated in the rectification unit and the source air to exchange heat with each other.
In the present invention, the rectification unit may be a cryogenic air separation device. In the present invention, the main evaporator has a function of evaporating the liquid nitrogen produced by the liquid nitrogen production device or the liquid oxygen produced by the liquid oxygen production device, and may be an air type evaporator or may be a warm-water type evaporator.
In the present invention, the impurity removal unit has a function of removing impurities in the gas obtained by vaporizing the liquid nitrogen produced by the liquid nitrogen production device or the liquid oxygen produced by the liquid oxygen production device. The impurity removal unit may be of a getter type, and may remove impurities such as CO, H2 and the like, or may be of an adsorption type, and may remove water and CO2.
According to the above configuration, the vaporized liquefied gas which is supplied from the spare gas supply pipe and/or the gas obtained by vaporizing the liquefied gas produced by the liquefied gas production device can be supplied with high purity. Further, even when the liquefied gas supply system stops due to loss of power supply or the like, gas can be continuously supplied because the nitrogen gas supply spare system is included. Further, by providing the heating unit, operation can be performed with low power.
(Invention 1 1 )
A first liquefied gas spare supply method according to the present invention includes
a first detection step of detecting that supply of gas is interrupted or stopped from main supply,
a power supply step of supplying power to a liquefied gas pump by using a generator, based on a detection result of the first detection step, a first temperature increasing step of vaporizing liquefied gas fed from a storage tank by the liquefied gas pump to a first temperature lower than a surrounding environment temperature to change the liquefied gas to gas, by using an evaporator,
a second temperature increasing step of increasing a temperature of the gas at the first temperature which is vaporized in the first temperature increasing step to a second temperature higher than the first temperature, by using a heat exchange unit, and
a backup supply step of feeding the gas increased in temperature to the second temperature in the second temperature increasing step, to a main supply side.
Further, a second liquefied gas spare supply method according to the present invention includes
a first detection step of detecting that supply of gas is interrupted or stopped from main supply,
a power supply step of supplying power to a liquefied gas pump and/or an electric heater by using a generator, based on a detection result of the first detection step,
a first temperature increasing step of vaporizing liquefied gas fed from a storage tank by the liquefied gas pump to a first temperature lower than a surrounding environment temperature to change the liquefied gas to gas, by using an evaporator,
a second temperature increasing step of increasing a temperature of the gas at the first temperature which is vaporized in the first temperature increasing step to a second temperature higher than the first temperature by using a heat exchange unit,
a third temperature increasing step of increasing a temperature of the gas increased in temperature to the second temperature in the second temperature increasing step to a third temperature higher than the second temperature in a heating unit using an electric heater, and a backup supply step of feeding the gas increased in temperature to the third temperature in the third temperature increasing step to a main supply side.
Further, a third liquefied gas spare supply method according to the present invention is the second liquefied gas spare supply method, and further includes
a step of the generator supplying power to the liquefied gas pump and stopping or not supplying power to the electric heater, when the second temperature is a temperature higher than an impurity removing treatment temperature (T) in a chemical adsorption type impurity removal device, and the generator supplying power to the electric heater and the liquefied gas pump, when the second temperature is lower than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device, and the third temperature is a temperature higher than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device.
The liquefied gas spare supply method according to the invention described above may further have the following steps.
A second detection step of detecting that supply of gas is restarted or started from the main supply, and a power stopping step of stopping supply of power to the liquefied gas pump and/or the electric heater based on a detection result in the second detection step are included.
A step of storing liquefied gas in a storage tank is included.
A step of feeding the liquefied gas to downstream from the storage tank by the liquefied gas pump is included.
The first detection step is a step of measuring an inner pressure of the main pipe or the spare gas supply pipe by a pressure gauge, and when the measured inner pressure is a threshold value or less, power may be supplied by using the generator for the liquefied gas pump and/or the electric heater in the power supply step.
A step of performing control so as to operate the generator by the generator control unit when the pressure measured by the pressure gauge drops to or below a threshold value may be included.
The second detection step may be a step of detecting information indicating that supply of gas is restarted or started from the main gas production unit, for example.
In the respective components of the method of the present invention, similar components to the components in the system of the invention described above have the same functions and operations.
In the liquefied gas spare supply method according to the present invention, the heating medium is a cooling fluid that cools the generator, and a step of circulating the cooling fluid to the heat exchange unit and the generator can be included.
(Invention 12)
A gas supply method with a backup according to the present invention is a method for supplying gas by vaporizing liquefied gas by a main evaporator, and includes
a step of supplying gas obtained by vaporizing liquefied gas with an evaporator from a gas production unit to a downstream process through a main pipe,
an impurity removing step of removing impurities in the gas in an impurity removal unit disposed in the main pipe, and
a step of the liquefied gas spare supply method described above, which is a step of supplying similar gas to the gas, through a spare gas supply pipe that joins the main pipe at an upstream side from the impurity removal unit. In the respective components of the method of the present invention, the similar components to the components in the system of the invention described above have the same functions and operations. Brief Description of the Drawings
[Figure 1 ] Figure 1 is a diagram illustrating a configuration example of a gas production system of embodiment 1 .
[Figure 2] Figure 2 is a diagram illustrating a configuration example of a gas production system of embodiment 2.
[Figure 3] Figure 3 is a diagram illustrating a configuration example of a gas production system of embodiment 3.
[Figure 4] Figure 4 is a diagram illustrating a configuration example of a gas production system of embodiment 4.
[Figure 5] Figure 5 is a diagram illustrating a configuration example of a gas production unit.
Description of Embodiments
Hereinafter, several embodiments of the present invention will be described. The embodiments that will be described hereinafter only explain examples of the present invention. The present invention is not limited by the following embodiments in any way, and also includes various modified modes that are carried out in the range without changing the gist of the present invention. Note that all components described hereinafter are not always essential components of the present invention.
(Embodiment 1 )
A liquefied gas supply system 1 with a backup of embodiment 1 is illustrated in Figure 1 and Figure 5. At a normal time, liquefied gas (nitrogen in the present embodiment) is supplied to a nitrogen gas consumption point (also referred to as a
downstream process) by a main pipe 6L from a gas production unit 51 . In the main pipe L6, an impurity removal unit 41 is disposed. In the present example, a getter that removes CO, CO2 and the like is disposed.
The gas production unit 51 is a nitrogen gas production device.
Figure 5 illustrates a content of the gas production unit 51 . The nitrogen gas production device is a cryogenic air separation device. Source air is taken into an air compression unit 71 , and is compressed. The compressed source air is cooled in a source gas heat exchange unit 72. Impurities
(water, CO2 and the like) in the source air which is cooled in the source gas heat exchange unit 72 are removed in a purification unit 73. The source air which is generated in the purification unit 73 is cooled in a main heat exchange unit 74 and is liquefied. The liquefied source air is separated into a nitrogen and an oxygen in a rectification unit 75. The separated nitrogen gas is heated by heat exchange with the source air in the aforementioned main heat exchange unit 74, and may be supplied to the main pipe L6. The separated liquid nitrogen is temporarily stored in a tank 76, and thereafter may be vaporized in a main evaporator 77, but the liquid nitrogen does not have to be taken out. The nitrogen gas vaporized in the aforementioned main evaporator 77 is supplied to the main pipe L6.
Here, it is conceivable that sufficient nitrogen gas cannot be supplied from the main pipe L6 for a reason of loss of the power supply, maintenance of the gas production unit and the like. In such a case, a pressure in the main pipe L6 is reduced, and a pressure in a spare gas supply pipe L4 that connects to the main pipe L6 is also reduced. Reduction in pressure is detected by pressure measurement by a pressure gauge 20 that is disposed in the spare gas supply pipe L4. When the pressure measured by the pressure gauge 20 reaches a threshold value (1 .0 MPa in the present example) or less, a power generator 15 is operated by a power generator control unit 31 .
When the power generator 15 is operated, power is supplied to a liquefied gas pump 13 and an electric heater of a heating unit 14.
When power is supplied to the liquefied gas pump 13, and the liquefied gas pump 13 is operated, liquefied gas (nitrogen in the present embodiment) which is stored in a storage tank 1 1 is led out from the aforementioned storage tank 1 1 by the liquefied gas pump 13, and is fed in a liquid state to an evaporator 12 at a downstream side.
The liquid nitrogen which is introduced into the evaporator 12 is caused to transition in state into gas in the evaporator 12. Here, the evaporator 12 is an air type evaporator, and surrounding environment air gives heat to the liquefied gas, whereby the liquid nitrogen transitions into nitrogen gas in a gaseous state from a liquid state. A liquid nitrogen temperature at a time of introduction into the evaporator is, for example, -195°C. The liquid nitrogen becomes nitrogen gas at a first temperature (-15°C in the present example) which is lower than the surrounding environment temperature (0°C in the present example) in the aforementioned evaporator 12, and is led out to an evaporation gas supply pipe L2 from the evaporator 12.
The nitrogen gas which passes through an inside of the evaporation gas supply pipe L2 is introduced into a heat exchange unit 16. In the present embodiment, exhaust gas from the generator 15, which is a heating medium, is fed to the heat exchange unit 1 6, and the exhaust gas and the nitrogen gas perform heat exchange. Thereby, the nitrogen gas is heated from the first temperature (-15°C in the present example) to a second temperature (-6°C in the present example). The heated nitrogen gas is led out to a heated gas introduction pipe L3 from the heat exchange unit 1 6.
The heat exchange unit 1 6 includes a heating medium passage having a heating medium inlet that receives the heating medium, and a heating medium outlet that discharges the received heating medium, and a gas passage in which gas that is fed from the evaporator 12 flows, and the gas passage L2 is disposed at an upstream side in a gas flow direction, and has an upstream side 121 where a temperature of the gas passing therethrough is low, and a downstream side 122 where gas having a higher temperature than gas passing through a low-temperature end portion passes. The heating medium inlet is disposed at the downstream side 122, and the heating medium outlet is disposed at the upstream side 121 .
The nitrogen gas passing through the heated gas introduction pipe L3 is introduced into a heating unit 14. By a multitubular electric heater in the heating unit 14, the nitrogen gas is heated from the second temperature (-6°C in the present example) to a third temperature (5°C in the present example) which is set in advance. The third temperature is determined in accordance with characteristics of the impurity removal unit 41 . In the present example, the impurity removal unit 41 is a getter that removes CO and CO2 by chemical adsorption, so that in order to exhibit impurity removing performance, the nitrogen gas temperature needs to be 0°C or more.
Therefore, the third temperature was set at 5°C. As for a heating
temperature by the electric heater, the electric heater control unit feedback- controls the electric heater so that a first thermometer 21 that measures a gas temperature inside of the spare gas supply pipe L4 indicates a third temperature.
According to the above configuration, even when the nitrogen gas which is supplied from the main pipe L6 is stopped or becomes insufficient due to power supply loss or the like, nitrogen gas can be continuously supplied from the liquefied gas supply spare system according to the present invention. The nitrogen gas which is supplied is heated to a predetermined temperature, and has high purity because impurities are efficiently removed in the impurity removal unit 41 .
Table 1 shows a result of comparing a load at a time of supplying nitrogen gas at a flow rate of 25000 Nm 3 /h, a pressure of 10 bar, and a temperature of 5°C in the liquefied gas supply spare system according to the present embodiment 1 with a system according to a system that has no heat exchange unit (referred to as comparative example 1 . The system without including the heat exchange unit 1 6 in Figure 1 ).
(Heat loads in embodiment 1 and comparative example 1 )
The evaporators which vaporize a liquid nitrogen are used in both the present embodiment 1 and comparative example 1 . In the aforementioned evaporator, a liquid nitrogen at -195°C transitions in state into nitrogen gas at -15°C. In any case, heat that was given to the liquid nitrogen from ambient air by the air type evaporator was 3343 kW. In order to make the nitrogen gas at -15°C which is generated in the evaporator nitrogen gas at 5°C, it is necessary to further give 31 kW of heat to the nitrogen gas.
In comparative example 1 , it is necessary to supply all of 31 kW of heat by the electric heater of the heating unit 14. Meanwhile, in the present embodiment 1 , 14 kW of heat is given from the heat exchange unit (a calculation basis will be described later). Consequently, heat that is supplied by the electric heater is 31 -14=17 kW.
(Electric loads in embodiment 1 and comparative example 1 )
An electric load that is necessary when the liquefied gas pump 13 feeds a liquid nitrogen in an amount corresponding to nitrogen gas at a flow rate of 25000 Nm3/h to the evaporator 12 is 30 kW. The electric load of the liquefied gas pump is the same in embodiment 1 and comparative example 1 .
In embodiment 1 , the generator supplies 30 kW of power to the liquefied gas pump 13, and supplies 17 kW of power to the electric heater. Therefore, a total amount of power that is supplied by the generator is 30 + 17 = 47 kW.
In comparative example 1 , the generator supplies 30 kW of power to the liquefied gas pump 13, and supplies 31 kW of power to the electric heater. Therefore, a total amount of power which is supplied by the generator is 30 + 31 = 61 kW.
(Contribution of heat medium from generator in embodiment 1 )
Power generation efficiency of the generator in embodiment 1 was 40%. Therefore, 47 kW corresponding to 40% is supplied to the liquefied gas pump 13 and the electric heater as electric power. 70.5 kW
corresponding to remaining 60% is mainly discharged into exhaust gas as heat. Heat that was given to the nitrogen gas by the exhaust gas which was a heating medium was 14 kW corresponding to 20% of 70.5 kW. The 14kW is given to the nitrogen gas in the heat exchange unit according to
embodiment 1 .
(Contribution of heating medium from generator in embodiment 1 )
The electric load of the electric heater was 17 kW in embodiment 1 , whereas the electric load was 31 kW in comparative example 1 . Therefore, in embodiment 1 , the electric load relating to the electric heater was able to be reduced by 45% more than in comparative example 1 .
The electric load of the generator was 47 kW in embodiment 1 , whereas the electric load of the generator was 61 kW in comparative example 1 . Therefore, in embodiment 1 , the electric load relating to the generator was able to be reduced by 23% more than in comparative example 1 .
Table 1
(Another embodiment)
While the gas production device in embodiment 1 produces a liquid nitrogen, but may produce a liquid oxygen or the like without being limited to this, and may store and supply liquefied natural gas.
The first thermometer in embodiment 1 measures a gas temperature inside the spare gas supply pipe L4, but may measure a pipe temperature of the spare gas supply pipe L4 without being limited to this.
The impurity removal unit 41 in embodiment 1 is a getter that removes CO and H2, but may remove CO2 and H2O without being limited to this.
The pressure gauge 20 in embodiment 1 is disposed in the spare gas supply pipe L4, but may be disposed in the main pipe L6 without being limited to this. When the impurity removal unit 41 is disposed in the spare gas supply pipe L4, the pressure gauge 20 may be disposed at an upstream side of the impurity removal unit 41 , but may be disposed at a downstream side of the impurity removal unit 41 . When the impurity removal unit 41 is disposed in the main pipe L6, the pressure gauge 20 may be disposed at the upstream side of the impurity removal unit 41 , but may be disposed at a downstream side of the impurity removal unit 41 .
The generator 15 in embodiment 1 supplies power to both the liquefied gas pump 13 and the electric heater of the heating unit 14, but is not limited to this, and two generators are disposed, power may be supplied to the liquefied gas pump 13 from one of the generators, whereas power may be supplied to the electric heater from the other generator.
[0076] In embodiment 1 , the heat exchange unit 1 6 and the evaporator 12 are separate bodies, but the present invention is not limited to this, and the heat exchange unit and the evaporation unit may be configured to be integrated as in embodiment 2.
In embodiment 1 , the electric heater control unit controls the electric heater based on the measurement result of the thermometer 21 , but the present invention is not limited to this. As in embodiment 2 or embodiment 3, a thermometer 22 and a thermometer 23 are further included, and the electric heater control unit may control the electric heater based on individual measurement values thereof or a combination of the two or more
measurement values.
(Embodiment 2)
Embodiment 2 will be described hereinafter with use of Figure 2.
Note that explanation of components having similar functions to those in embodiment 1 will be omitted. At a normal time, liquefied gas (oxygen gas in the present
embodiment) is supplied to an oxygen gas consumption point by the main pipe L6 from the gas production unit 51 .
When sufficient oxygen gas cannot be supplied from the main pipe L6 for the reason of loss of power supply, maintenance of the gas production unit or the like, the pressure in the main pipe L6 is reduced. The pressure reduction is detected by pressure measurement by the pressure gauge 20. When the pressure measured by the pressure gauge 20 drops to or below a threshold value (1 .0 MPa in the present example), the generator control unit 31 operates the generator 15.
When the generator 15 is operated, power is supplied to the liquefied gas pump 13 and the electric heater of the heating unit 14.
When power is supplied to the liquefied gas pump 13 and the liquefied gas pump 13 is operated, the liquefied gas (oxygen in the present
embodiment) which is stored in the storage tank 1 1 is led out from the storage tank 1 1 by the liquefied gas pump 13, and is fed in the liquid state to the evaporator 12 at the downstream side.
The liquid oxygen which is introduced into the evaporator 12 is caused to transition in state into gas in the evaporator 12. Here, the evaporator 12 is an air type evaporator. A liquid oxygen temperature at the time of introduction into the evaporator is, for example, -182°C. The liquid oxygen becomes oxygen gas at the first temperature (-15°C in the present example) lower than a surrounding environment temperature (0°C in the present example) in the aforementioned evaporator 12. In the present embodiment, exhaust gas of the generator, which is a heating medium, is blown to a downstream side of a tube composing the evaporator 12. An exhaust gas blown position is the downstream side 122 of the evaporator 12. The exhaust gas flows to the upstream side 121 of the evaporator 12 while giving heat to the oxygen gas at the downstream side 122. In this way, a liquid oxygen is vaporized in the evaporator 12 to reach the aforementioned first temperature, and further reaches the second temperature by heat exchange with the exhaust gas of the generator, which is the heating medium. The exhaust gas which is introduced into the evaporator is released from a heating medium outlet provided in the evaporator.
The oxygen gas at the second temperature is led out from the evaporator 12, and is fed to the heating unit 14 through the heated gas introduction pipe L3. By the multitubular electric heater in the heating unit 14, the oxygen gas is heated to a third temperature (5°C in the present example) which is set in advance from the second temperature.
As for the heating temperature by the electric heater, the electric heater control unit performs feedback control of the electric heater so that a temperature measurement result by the thermometer 21 becomes the third temperature, based on the temperature measurement result by the first thermometer 21 that measures the gas temperature in the spare gas supply pipe L4 and the temperature measurement result by the second thermometer that measures the gas temperature in the heated gas introduction pipe.
According to the above configuration, even when the oxygen gas which is supplied from the main pipe L6 is stopped or becomes insufficient due to power supply loss or the like, oxygen gas can be continuously supplied from the liquefied gas supply spare system according to the present invention.
Table 2 shows a result of comparing a load at a time of supplying oxygen gas at a flow rate of 25000 Nm 3 /h, a pressure of 10 bar, and a temperature of 5°C in the liquefied gas supply spare system according to the present embodiment 2, with a system according to a system that has no heat exchange unit (referred to as comparative example 2. The system without including the heat exchange unit 1 6 in Figure 2).
(Heat loads in embodiment 2 and comparative example 2)
The evaporators which vaporize a liquid oxygen are used in both the present embodiment 2 and comparative example 2. In the aforementioned evaporator, a liquid oxygen at -182°C transitions in state into oxygen gas at -15°C. In either case, heat that was given to the liquid oxygen from ambient air by the air type evaporator was 3597 kW. In order to make the oxygen gas at -15°C which is generated in the evaporator oxygen gas at 5°C, it is necessary to give 31 kW of heat to the oxygen gas.
In comparative example 1 , it is necessary to supply all of 31 kW of heat by the electric heater of the heating unit 14. Meanwhile, in the present embodiment 1 , 14 kW of heat is given from the heat exchange unit (a calculation basis will be described later). Consequently, heat that is supplied by the electric heater is 31 -14=17 kW.
(Electric loads in embodiment 2 and comparative example 2)
An electric load that is necessary when the liquefied gas pump 13 feeds a liquid oxygen in an amount corresponding to oxygen gas at a flow rate of 25000 Nm 3 /h to the evaporator 12 is 30 kW. The electric loads of the liquefied gas pumps are the same in embodiment 2 and comparative example 2.
In embodiment 2, the generator supplies 30 kW of power to the liquefied gas pump 13, and supplies 17 kW of power to the electric heater. Therefore, a total amount of power that is supplied by the generator is 30 + 17 = 47 kW.
In comparative example 2, the generator supplies 30 kW of power to the liquefied gas pump 13, and supplies 31 kW of power to the electric heater. Therefore, a total amount of power which is supplied by the generator is 30 + 31 = 61 kW.
(Contribution of heating medium from generator in embodiment 2) Power generation efficiency of the generator in embodiment 2 was 40%. Therefore, 47 kW corresponding to 40% is supplied to the liquefied gas pump 13 and the electric heater as electric power. 70.5 kW
corresponding to remaining 60% is mainly discharged into exhaust gas as heat. Heat that was given to the oxygen gas by the exhaust gas which was a heating medium was 14 kW corresponding to 20% of 70.5 kW. The 14kW is given to the oxygen gas in the heat exchange unit according to
embodiment 2.
(Contribution of heating medium from generator in embodiment 2) The electric load of the electric heater was 17 kW in embodiment 2, whereas the electric load was 31 kW in comparative example 2. Therefore, in embodiment 1 , the electric load relating to the electric heater was able to be reduced by 45% more than in comparative example 2.
The electric load of the generator was 47 kW in embodiment 2, whereas the electric load of the generator was 61 kW in comparative example 2. Therefore, in embodiment 2, the electric load relating to the generator was able to be reduced by 23% more than in comparative example
2.
Table 2 Embodiment 2 Comparative example 2
Heat given to liquid oxygen by evaporator 3597 kW 3597 kW 12
(-182°C→-15°C)
Heat given to oxygen gas by heat 31 kW 31 kW exchange unit 14 and electric heater
(total value of * 1 and * 2 described below)
(-15°C→5°C)
Heat given to oxygen gas in heat 14 kW 0 kW exchange unit * 1 (without heat exchange unit)
Heat given to oxygen gas by electric 17 kW 31 kW heater * 2
Load (necessary power amount) of 30 kW 30 kW liquefied gas pump 13 * 3
Load (necessary power amount) of 47 kW 61 kW generator 15
(total value of * 2 and * 3 described above)
(Another embodiment)
While the heating medium inlet and the heating medium outlet in embodiment 2 are provided in the evaporator 12, but the present invention is not limited to this, and the heating medium may be configured to be blown in a duct form to the downstream side in the tubes configuring the evaporator 12. In this case, the heating medium which is blown is directly released to an environment around the evaporator 12.
[0093] In embodiment 2, the heat exchange unit 1 6 and the evaporator 12 are integrated, but the present invention is not limited to this, and the heat exchange unit and the evaporation unit may be configured to be separate bodies as in embodiment 1 .
In embodiment 2, the electric heater control unit controls the electric heater based on the measurement results of the thermometers 21 and 22, but the present invention is not limited to this. The electric heater control unit may control the electric heater based on only the thermometer 21 as in embodiment 1 , or as in embodiment 3, a thermometer 23 is further included, and the electric heater control unit may control the electric heater based on individual measurement values thereof or a combination of the two or more measurement values.
(Embodiment 3)
Embodiment 3 will be described hereinafter with use of Figure 3.
Note that explanation of components having similar functions to those in embodiment 1 or 2 will be omitted.
At a normal time, liquefied gas (methane gas in the present
embodiment (hereinafter, also referred to as LNG)) is supplied to a methane gas consumption point by the main pipe L6 from the gas production unit 51 .
When the pressure measured by the pressure gauge 20 reaches a threshold value (1 .0 MPa in the present example) or less, the generator control unit 31 operates the generator 15.
When the generator 15 is operated, power is supplied to the liquefied gas pump 13 and the electric heater of the heating unit 1 6.
When power is supplied to the liquefied gas pump 13 and the liquefied gas pump 13 is operated, the liquefied gas (LNG in the present embodiment) stored in the storage tank 1 1 is led out from the aforementioned storage tank 1 1 by the liquefied gas pump 13, and is fed in the liquid state to the evaporator 12 at the downstream side.
The LNG which is introduced into the evaporator 12 is caused to transition in state into gas in the evaporator 12. Here, the evaporator 12 is an air type evaporator. An LNG temperature at the time of introduction into the evaporator is, for example, -1 60°C. The LNG becomes methane gas at the first temperature (-15°C in the present example) lower than a surrounding environment temperature (0°C in the present example) in the aforementioned evaporator 12. The methane gas reaching the first temperature is led out to the evaporation gas supply pipe L2 from the evaporator 12.
The methane gas passing through the inside of the evaporation gas supply pipe L2 is introduced into the heat exchange unit 1 6. In the present embodiment, cooling water of the generator 15, which is a heating medium, is fed to the heat exchange unit, and exhaust gas and the methane gas perform heat exchange. A temperature of the cooling water rises by cooling the generator 15, and the temperature of the cooling water is reduced by giving heat to the methane gas in the heating unit. The cooling water with a reduced temperature is used in cooling the generator again by a heating medium circulation passage.
Thereby, the methane gas is heated to the second temperature (-6°C in the present example) from the first temperature (-15°C in the present example). The heated methane gas is led out to the heated gas introduction pipe L3 from the heat exchange unit 1 6.
The methane gas at the second temperature is led out from the evaporator 12, and is fed to the heating unit 14 through the gas to be heated introduction pipe L3. By the electric heater in the heating unit 14, the methane gas is heated to the third temperature (5°C in the present example) which is set in advance from the second temperature (-6°C in the present example).
As for the heating temperature by the electric heater, the electric heater control unit controls the electric heater so that a temperature measurement result by the thermometer 21 becomes the third temperature which is set in advance, based on the temperature measurement result by the first thermometer 21 that measures the gas temperature in the spare gas supply pipe L4, and temperature measurement results by the second thermometer 22 that measures the gas temperature in the gas to be heated introduction pipe, and the third thermometer 23 that measures the gas temperature in the evaporation gas supply pipe L2.
According to the above configuration, even when the methane gas which is supplied from the main pipe L6 is stopped or becomes insufficient due to power supply loss or the like, methane gas can be continuously supplied from the liquefied gas supply spare system according to the present invention.
Table 3 shows a result of comparing a load at a time of supplying methane gas at a flow rate of 25000 Nm 3 /h, a pressure of 10 bar, and a temperature of 5°C in the liquefied gas supply spare system according to the present embodiment 3, with a system according to a system that has no heat exchange unit (referred to as comparative example 3. The system without including the heat exchange unit 1 6 in Figure 3).
(Heat loads in embodiment 3 and comparative example 3)
The evaporators which vaporize a liquid oxygen are used in both the present embodiment 3 and comparative example 3. In the aforementioned evaporator, LNG at -1 60°C transitions in state into methane gas at -15°C. In both cases, heat that was given to LNG from ambient air by the air type evaporator was 4057 kW. In order to make the methane gas at -15°C which is generated in the evaporator methane gas at 5°C, it is necessary to further give 31 kW of heat to the methane gas.
In comparative example 1 , it is necessary to supply all of 31 kW of heat by the electric heater of the heating unit 14. Meanwhile, in the present embodiment 1 , 14 kW of heat is given from the heat exchange unit (a calculation basis will be described later). Consequently, heat that is supplied by the electric heater is 31 -14=17 kW.
(Electric loads in embodiment 3 and comparative example 3)
An electric load that is required when the liquefied gas pump 13 feeds LNG in an amount corresponding to methane gas at a flow rate of 25000 Nm 3 /h to the evaporator 12 is 30 kW. The electric loads of the liquefied gas pumps are the same in embodiment 3 and comparative example 3.
In embodiment 3, the generator supplies 30 kW of power to the liquefied gas pump 13, and supplies 17 kW of power to the electric heater. Therefore, a total amount of power that is supplied by the generator is 30 + 17 = 47 kW.
In comparative example 3, the generator supplies 30 kW of power to the liquefied gas pump 13, and supplies 31 kW of power to the electric heater. Therefore, a total amount of power which is supplied by the generator is 30 + 31 = 61 kW.
[0108] (Contribution of heating medium from generator in embodiment 3)
Power generation efficiency of the generator in embodiment 3 was 40%. Therefore, 47 kW corresponding to 40% is supplied to the liquefied gas pump 13 and the electric heater as electric power. 70.5 kW
corresponding to remaining 60% is mainly discharged into exhaust gas as heat. Heat that was given to the methane gas by the exhaust gas which was a heating medium was 14 kW corresponding to 20% of 70.5 kW. The 14kW is given to the methane gas in the heat exchange unit according to embodiment 3.
(Contribution of heating medium from generator in embodiment 3)
The electric load of the electric heater was 17 kW in embodiment 3, whereas the electric load was 31 kW in comparative example 2. Therefore, in embodiment 3, the electric load relating to the electric heater was able to be reduced by 45% more than in comparative example 3.
The electric load of the generator was 47 kW in embodiment 3, whereas the electric load of the generator was 61 kW in comparative example 3. Therefore, in embodiment 3, the electric load relating to the generator was able to be reduced by 23% more than in comparative example
3.
[Table 3]
(Another embodiment)
In embodiment 3, a flow meter 24 that measures an amount of gas that is supplied from the liquefied gas supply spare system is not provided, but the present invention is not limited to this, and may be configured to be provided with the flow meter 24. In this case, the flow meter 24 is disposed in the main pipe L6 or the spare gas supply pipe L4. As the flow meter, an orifice differential pressure gauge is used.
The electric heater control unit 30 controls the electric heater so that the temperature measured by the aforementioned first thermometer 21 becomes the aforementioned third temperature, based on any one or two or more of the respective temperatures measured by the aforementioned third thermometer 23, the aforementioned second thermometer 22 and the aforementioned first thermometer, and a flow rate measured by the
aforementioned flow meter 24.
In embodiment 3, the heat exchange unit 1 6 and the evaporator 12 are separate bodies, but the present invention is not limited to this, and the heat exchange unit and the evaporation unit may be configured to be integrated as in embodiment 2.
In embodiment 3, the electric heater control unit controls the electric heater based on the measurement results of the thermometers 21 , 22 and 23, but the present invention is not limited to this, and the electric heater control unit may control the electric heater based on the individual measurement value of the thermometer 21 or the thermometer 22, as in embodiment 1 or embodiment 2.
(Embodiment 4)
In embodiment 4 illustrated in Figure 4, the flow meter 24 (for example, a mass flow meter) is disposed in the main pipe L6. The elements with the same reference signs have similar functions to those in the above described embodiments, so that explanation thereof will be omitted.
The electric heater control unit 30 can control the electric heater so that a temperature measured by the first thermometer 21 becomes the third temperature, based on any one or two or more of respective temperatures measured by the third thermometer 23, the second thermometer 22 and the first thermometer 21 , and the flow rate measured by the flow meter 24.
In the present embodiment 4, the flow meter 24 is disposed in the main pipe, but the present invention is not limited to this, and the flow meter 24 may be disposed in the spare gas supply pipe L4.
Further, the flow meter 24 may be also provided in embodiments 1 to 3 without being limited to the configuration of embodiment 4, and the electric heater control unit 30 may control the electric heater so that the temperature measured by the first thermometer 21 becomes the third temperature based on the measurement results of the respective thermometers and the flow rate measured by the flow meter 24.
(Other embodiments of embodiments 1 to 4)
The above described embodiments 1 to 4 all include the heating units having the electric heaters and are configured to supply power to the electric heaters, but may be configured to include no heating units having electric heaters or may be configured to supply no power to the electric heaters even though embodiments 1 to 4 include the heating units having the electric heaters. When the gas temperature reaches a necessary and sufficient temperature by increase in temperature by the heat exchange unit, the electric heater does not have to be operated, and further reduction in power supply amount can be achieved.
(Embodiment s)
A liquefied gas spare supply method includes
a first detection step of detecting that supply of gas is interrupted or stopped from main supply,
a power supply step of supplying power to a liquefied gas pump 13 and/or an electric heater by using a generator 15, based on a detection result of the first detection step,
a first temperature increasing step of vaporizing liquefied gas fed from a storage tank by the liquefied gas pump 13 to a first temperature lower than a surrounding environment temperature to change the liquefied gas to gas, by using an evaporator 12,
a second temperature increasing step of increasing a temperature of the gas at the first temperature which is vaporized in the first temperature increasing step to a second temperature higher than the first temperature by using a heat exchange unit 1 6,
a third temperature increasing step of increasing a temperature of the gas increased in temperature to the second temperature in the second temperature increasing step to a third temperature higher than the second temperature in a heating unit 14 using an electric heater,
a backup supply step of feeding the gas increased in temperature to the third temperature in the third temperature increasing step to a main supply side,
a second detection step of detecting that supply of gas is restarted or started from the main supply, and
a power stopping step of stopping supply of power to the liquefied gas pump 13 and/or the electric heater based on a detection result in the second detection step.
The above described liquefied gas spare supply method may further include
a step of the generator supplying power to the liquefied gas pump and stopping or not supplying power to the electric heater, when the second temperature is a temperature higher than an impurity removing treatment temperature (T) in a chemical adsorption type impurity removal device, and the generator supplying power to the electric heater and the liquefaction gas pump, when the second temperature is lower than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device, and the third temperature is a temperature higher than the impurity removing treatment temperature (T) in the chemical adsorption type impurity removal device.
Further, a liquefied gas spare supply method according to another embodiment includes a first detection step of detecting that supply of gas is interrupted or stopped from main supply,
a power supply step of supplying power to a liquefied gas pump by using a generator, based on a detection result of the first detection step, a first temperature increasing step of vaporizing liquefied gas fed from a storage tank by the liquefied gas pump to a first temperature lower than a surrounding environment temperature to change the liquefied gas to gas, by using an evaporator,
a second temperature increasing step of increasing a temperature of the gas at the first temperature which is vaporized in the first temperature increasing step to a second temperature higher than the first temperature, by using a heat exchange unit, and
a backup supply step of feeding the gas increased in temperature to the second temperature in the second temperature increasing step, to a main supply side.
The liquefied gas spare supply method further has the following steps.
A step of storing liquefied gas in the storage tank 1 1 , and a step of feeding the liquefied gas to downstream from the storage tank by the liquefied gas pump 13 are included.
The first detection step is a step of measuring an inner pressure of the main pipe L6 or the spare gas supply pipe L4 by the pressure gauge 20, and when the measured inner pressure is a threshold value or less, the power supply step supplies power from the generator 15 to the liquefied gas pump 13 and/or the electric heater.
A step of performing control so as to operate the generator 15 by the generator control unit 31 when the pressure measured by the pressure gauge 20 drops to a threshold value or less is included. Further, the heating medium is a cooling fluid that cools the generator 15, and a step of circulating the cooling fluid between the heat exchange unit 1 6 and the generator 15 is included.
(Embodiment 6)
A gas supply method with a backup is a method for supplying gas by vaporizing liquefied gas by a main evaporator, and includes
a step of supplying gas obtained by vaporizing liquefied gas in an evaporator from a gas production unit 51 to a downstream process through a main pipe L6,
an impurity removing step of removing impurities in the gas in an impurity removal unit 41 disposed in the main pipe L6, and
a step of the liquefied gas spare supply method described above, which is a step of supplying similar gas to the gas, through a spare gas supply pipe L4 that joins the main pipe L6 at an upstream side from the impurity removal unit 41 .
Reference Signs List
1 Liquefied gas supply spare system
1 1 Storage tank
12 Evaporator
13 Liquefied gas pump
14 Heating unit
15 Generator
1 6 Heat exchange unit
20 Pressure gauge
21 First thermometer
22 Second thermometer
23 Third thermometer 24 Flow meter
30 Heater control unit
31 Generator control unit
41 Impurity removal unit
51 Gas production unit
71 Air compression unit
72 Source gas heat exchange unit
73 Purification unit
74 Main heat exchange unit
75 Rectification unit
76 Tank
77 Main evaporator
L2 Evaporation gas supply pipe
L3 Gas to be heated introduction pipe L4 Spare gas supply pipe
L6 Main pipe
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