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Title:
THE METHOD OF A COAL OR COAL BLEND EXPANSION PRESSURE DETERMINATION AND THE DEVICE FOR THE METHOD
Document Type and Number:
WIPO Patent Application WO/2012/168802
Kind Code:
A1
Abstract:
The essence of this invention is the determination of the coal or coal blend expansion pressure and the selection of the appropriate device for this determination. The expansion pressure determination method for the coal or the coal blend, in conducting the laboratory test, is characterised by the fact that a coal or coal blend sample is subjected to heating in a crucible located inside of the perforated sleeve and that on the outside of the sleeve, there is an inert granular material that has a size greater than the holes in the sleeve. The crucible itself is located in the electric oven and is heated around its circumference at a rate of several degrees per minute from the ambient temperature to a temperature greater than the end coal plasticity, with the temperature being measured by a thermoelement placed on the sleeve wall.

Inventors:
SCIAZKO MAREK (PL)
SOBOLEWSKI ALEKSANDER (PL)
MERTAS BARTOSZ (PL)
Application Number:
IB2012/051911
Publication Date:
December 13, 2012
Filing Date:
April 17, 2012
Export Citation:
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Assignee:
INSTYTUT CHEMICZNEJ PRZERÓBKI WĘGLA (Zamkowa 1, Zabrze, PL-41-803, PL)
International Classes:
C10B57/00; G01N25/16
Foreign References:
JP2008143928A2008-06-26
KR20040106183A2004-12-17
JP2009144001A2009-07-02
JPH04272992A1992-09-29
ES524258A01984-11-01
Attorney, Agent or Firm:
KORGA, Leokadia (Bereniki 6/7, Gliwice, PL-44-117, PL)
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Claims:
The method of a coal or coal blend expansion pressure determination and the device for the method

Claims

The method of a coal or coal blend expansion pressure determination, in conducting the laboratory test, is characterised in that a coal or a coal blend sample is subjected to heating in a crucible located inside a perforated sleeve and that on the outside of the sleeve, there is an inert granular material that is greater in size than the holes in the sleeve where the crucible itself is located in the electric oven and is heated around its circumference at a rate of several degrees per minute from the ambient temperature to a temperature greater than the end coal plasticity, with the temperature being measured with a thermocouple placed on the sleeve wall.

The method according to claim 1 , is characterised in that the inert material is anthracite or coke breeze.

The method according to claim 1 , is characterised in that the inert material size distribution is 1 .0 - 1 .5 mm.

The method according to claim 1 , is characterised in that the coal/coal blend sample size is <5 mm.

The method according to claim 1 , is characterised in that the heating rate is 3 K/min.

The method according to claim 1 , is characterised in that the temperature measurement is conducted at the mid-height of the sample.

The device for the method of a coal or coal blend expansion pressure determination consists of an electrically heated oven and measurement devices, is characterised in that the crucible (2) is located inside the electrically heated oven (1.) where inside of the crucible (2) is a perforated sleeve (3) with a guard for temperature measurement unit (5) located on its surface where a coal sample (4) is placed in the sleeve (3), which is held down with a piston (6) that is adjacent to the force measurement system (7) and heating control and pressure measurements are performed by the control system (8). The device according to claim 7, is characterised in that diameter of the sleeve (3) holes is 1 mm.

The device according to claim 7, is characterised in that the guard of the thermoelement (5) is located at the mid-height of the sleeve (3).

Description:
The method of a coal or coal blend expansion pressure determination and the device for the method

The subject of the invention is the method of a coal or coal blend expansion pressure determination and the subsequent appropriate device for the method.

Expansion pressure is a significant phenomenon that occurs during the coking process and has an impact on the safety of the coke oven battery walls as well as on the quality of the produced coke. Charged coal blend into the coking chamber and indirectly heated is subject to carbonisation, and in the specified temperature range, it may soften, what may exert considerable pressure on the chamber walls. This may lead to damage or, in extreme cases, to the destruction of the chamber walls. When planning the coking process, it is essential to be aware of the value of the coal charge expansion pressure, where a high value indicates the possibility of high-quality blast furnace coke production. However, the safety of the ceramic block of the coking chamber may be endangered by this production, and in extreme conditions, there is potential for its destruction.

There are a few known methods of measuring and forecasting the value of the expansion pressure that use direct and indirect measurements.

A muffle oven and a steel box are used in the muffle assessment test to determine the coal expansion pressure; this test is commonly used in the literature. In this test, the coal sample is compacted in a steel box, which is subsequently placed into a muffle oven and heated to 900°C. The level of pressure is estimated in the expansion test based on the distortion of the steel box walls and the appearance of the coke after the sample has been removed from the oven and the steel box has been cooled down with water. Another laboratory device that is used for the nornnalised expansion pressure measurement is the Polish Standard PN/G-04522. This device consists of an electric oven with temperature adjustment via a resistor, a crucible with a replaceable perforated bottom, a thermoelement with a temperature gauge and a small piston connected to a mercury pressure gauge. Determining the expansion pressure using this device consists of measuring the force with the mercury pressure gauge, which is located directly on the small piston that is placed on the coal sample, and the expansion pressure is calculated with the appropriate formula. In this method, an 80 g sample of coal with a size below 1 .4 mm is compacted in the crucible in a dry-air condition. Then, the oven is heated to 250°C, and the crucible containing the sample is entered into the oven and heated at a rate of 10°C/min. The oven heating elements are located in the bottom part of the oven, the thermoelement rests on the bottom of crucible, and the crucible with the sample is heated from the bottom. Pressure gauge readings, which determine the force acting on the small piston, are read at specified intervals. The expansion pressure is calculated based on the maximum force acting on the small piston.

Another well-known solution is called a test stand the method of investigating the expansion pressure phenomenon. In this procedure the expansion pressure is determined by placing the 50 - 100 g coal sample, with a size composition of 1 -3 mm, in a steel sleeve and inserting the sleeve into the oven. The sample then is heated in a circumferential manner around the sleeve. The sample temperature and pressure acting on the small piston are measured during each test.

Another group of assessment methods for the determination of the expansion pressure are called indirect methods. In these methods, a physical value is measured and then correlated with the expansion pressure.

The device from the Spanish patent description No. 524,258 of the INCAR CSIC Institute allows the expansion and contraction of the coals or the coal blend to be measured. Using this device, comparative tests are conducted; the expansion pressure is measured in the oven using a movable wall. The readings from these measurements show that the coal samples with a contraction of at least 10 mm are safe in terms of the expansion pressure. This method does not provide information regarding the expansion pressure, but it does provide information regarding the potential propensity of charge contraction in the chamber, which causes so-called "heavy runs" in the coking chamber.

A different solution for the determination of the expansion pressure is the measurement of the internal gas pressure, which is monitored by probes located inside the coal charge. The value of the gas pressure being measured is often linked to the value of the expansion pressure; however, there are no unequivocal results confirming the occurrence of such a relationship.

At present, the most reliable method for determining the expansion pressure is the use of a movable wall oven. This allows coking test to be conducted with a coal charge of approximately 300-500 kg, depending on the construction of the oven. One of the oven's walls is linked to the force sensor, which allows a continuous measurement of the force acting on this wall. This force is then automatically recalculated into an expansion pressure. The advantage of the use of such a device is the high reliability of the results obtained. However, this type of testing is highly expensive, which results from the necessity of employing several people for oven operation, the amount of the coal charge and the high cost of electricity necessary to heat this charge to a temperature over 1000°C for 12 or more hours.

The current methods for measuring the expansion pressure usually do not produce comparable results, which are measured in the movable wall oven with the value of this parameter. This lack of comparable results is primarily caused by the following: 1 ) only a visual assessment of the effect of the pressure action is possible; 2) the measurements include not only of the expansion pressure but also the pressure of the released gases; or 3) the measurement is a result of the substitute parameter and is only linked to the expansion pressure, as seen in the case of the contraction measurement method described in the Spanish Patent of INCA CSIC Institute. 95 The objective of the method, according to this invention, is to determine, in a reliable way, the values of the coal and the coal blend expansion pressure in laboratory conditions by simulating the behaviour of the coal throughout the industrial coking process in the coking chamber. loo The determination of the method of the expansion pressure of the coal or the coal blend, in conducting the laboratory test, is characterised, according to the invention, by the fact that a coal or a coal blend sample is subjected to heating in a crucible located inside of the perforated sleeve that has on the outside some inert granular material of a size bigger than the holes in the

105 sleeve. The crucible itself is located in the electric oven and heated around its circumference at a rate of several degrees per minute from ambient temperature to a temperature greater than the end coal plasticity, with the temperature being measured by a thermoelement placed on the sleeve wall. Favourably, when the inert material is either anthracite or coke breeze.

no Favourably, when the size composition of the inert material is 1 .0 - 1 .5 mm.

Favourably, when the size composition of the coal sample is <5 mm.

Favourably, when the rate of heating is 3 K/min.

Favourably, when the thermoelement is located at the mid-height of the sample.

us The device for the expansion pressure determination consists of an electrically heated oven and measuring gauges and, according to the invention, is characterised by the fact that the crucible is located inside the electrically heated oven. A perforated sleeve with a guarded temperature measurement unit is located inside of the oven. A coal sample is placed in

120 the sleeve, which is held down with a piston adjacent to a force measurement system, and heating control and pressure measurements are performed by the control system.

The determination of the expansion pressure proceeds favourably under the following conditions:

125 Favourably, when the holes of the sleeve are of 1 mm diameter. Favourably, when the guard of temperature measurement unit is located at the mid-height of the sleeve.

130 The essential advantage of this solution, according to the invention, is that the coal or the coal blend is subjected to heating in the crucible located outside the perforated sleeve. This allows the volatile matter being released to flow through it. In addition, the granular material placed outside the perforated sleeve prevents the volatile matter from travelling through the bed,

135 creating a resistance for the gases. This, in turn, makes it possible to simulate the gas evacuation path through the semi-coke and coke areas in the coking chamber. As a result of such an arrangement, the pressure being measured on the piston has its source in the expansion of the sample and is linked to the swelling of the individual grains and not to the pressure of the

140 gas being released.

An additional and vital advantage of the application of this method is the fact that the obtained results from the expansion pressure measurements can be quantitatively linked to the value of the expansion pressure being measured in the movable wall oven with a linear function.

145 Upon the application of this method for measuring the expansion pressure, according to the invention, we can create conditions similar to real industrial conditions and improve the accuracy of the experiments performed, which is not possible with the other known design solutions or with other methods of measuring the expansion pressure.

150

This novel method for measuring the expansion pressure and its execution are demonstrated in the following figures:

Fig. 1 - Crucible showing a schematic of the direction of the gas flow that 155 does not generate expansion pressure;

Fig. 2 - Diagram of the device for testing the expansion pressure. The device, according to the diagram shown in Fig. 2, consists of an oven 1 that is electrically heated where the crucible 2 is located. There is a perforated sleeve 3 in the crucible 2 with holes 3 mm in diameter. There is

160 a guard of the temperature measurement unit 5 at the mid-height of the sleeve 3. In the sleeve 3^ there is a coal sample 4 that is held down by a piston 6 that is adjacent to the force measurement system 7. The space between the internal wall of the crucible 2 and the sleeve 3 is filled in with coke breeze or anthracite 1 -1 .5 mm in size. The sample of coal/coal blend 4

165 with a size <5 mm is placed inside of the sleeve 3, and the piston 6 is attached. The piston 6 is adjacent to the force measurement system 7. Next, the heating of the oven 1 is started, and the control system 8 adjusts the heating to a rate of 3 K/min. The registration and archiving system 8 reads and continuously saves the data taken from the thermoelement, located in

170 the guard 5^ and the force measurement system 7.

The measurement is considered to have been completed after the temperature has reached 650°C.