Technical Field

Present disclosure is related to a sludge feed mechanism and method which provides feeding of the wastewater sludge to a fluidized bed combustion boiler from multiple points from the bottom of the boiler.

The disclosure is particularly related to a sludge feed mechanism and method which provides feeding of industrial, domestic or mixed type sludges with low or high calorific value, whose humidity rate vary between 60% and 90%, to the fluidized bed from multiple points from the bottom of the boiler.

Prior Art

In the fluidized bed boilers used today, the system can be fed both from the bottom and the top. In general, feeding from the top is commonly used. Feeding from the bottom differs according to the type of the fuel used. In the fluidized beds which fed from the bottom, coal, domestic waste, biomass and lignite are used as fuel.

In the present technique, the sludge is sent to the fluidized bed from the top, in solid form, after it has been dried. Feeding from multiple points is usually used in fluidized beds. However, it is not preferred to feed the sludge from multiple points.

In the known state of the art, the sludge is fed from the top. In order to provide sludge feeding from the top, the feed needs to be dried up to 40% of sludge. In order to provide drying, building a system is required. Using a drying process results in the loss of time, labor and costs.

The method of feeding the sludge from the top in the present technique does not provide homogenous combustion; therefore, the flame temperature decreases. A homogenous mixture cannot be obtained by feeding the sludge from the top, especially with fluidized beds. The combustion efficiency decreases depending on the decreasing in the flame temperature. Depending on that, high fuel consumption occurs.

The patent research conducted on the prior art revealed the technical content of the patent application numbered US2010192816A1 : The subject of the invention is a inner part of the furnace body which the sludge is being fed, divided to a bottom section; an upper section of the bottom part and a top section in the direction of height. The bottom section functions as a pyrolysis area in order to supply the fluidizing air which has a 1.1 or lower air ratio together with the fuel, with the purpose of breaking down the sludge thermally as the sludge is fluidized. The upper section of the bottom part functions as an upper-bed combustion area with the purpose of providing combustive air with the air ratio between 0.1 and 0.3, in order to create a local high-temperature place for the decomposition of N20. The top section functions as the perfect combustion area in order to combust the unburnt content thoroughly. The amount of N20 occurred during the sludge combustion can be reduced to a large extent, while keeping the amount of the auxiliary fuel use at the same level as a traditional combustion method.

The patent research conducted on the prior art revealed the technical content of the patent application numbered US2004103832A1 : A fluidization device, as the subject of the invention, according to a conventional method of burning organic waste products constitute a fluid panicle layer and causes an oxidizing fluidizing has to flow under the waste material in a combustion chamber, thus, the waste product is burnt. The stack gas is vacuumed back by means of an open gap over the particle layer and subjected to secondary combustion in a secondary reaction zone or a second combustion chamber. According to the known state of the art, the purpose of the invention causes a low nitrogen oxide production level on one hand while providing high efficiency for the combustion material in order to increase the efficiency of burning the organic waste material on the other.

The patent research conducted on the prior art revealed the technical content of the patent application numbered EP3054214 A1 : The subject of the invention is related to a method of feeding air to a fluidized bed boiler. The method is supplying primary air to a first combustion area under the fluidized bed and to pass the combustive air for the volatile substance to the first combustion area together with the fuel supply. A part of the combustive air for the volatile substance is supplied as a first combustive air source which is mixed with the fuel feed, and a part of the combustive air for the volatile substance is supplied as a second combustive air source which surrounds at least a part of the fuel source. The rate of the combustive air of the volatile air supplied in the first and second combustive air feeding is 10 to 25 m/s. The invention is also related to the fluidized bed boiler and fuel supply means.

Consequently, improvements are carried out for sludge feed mechanisms and thus, new embodiments which will eliminate the above-mentioned disadvantages and bring solutions for the present systems are required.

Description of the Invention

The present invention is related to a sludge feed mechanism and method which meets the above-mentioned requirements, eliminates all of the disadvantages and gets some additional advantages.

The main purpose of the invention is to provide the feeding of industrial, domestic or mixed type sludges with low or high calorific value, whose humidity rate vary between 60% and 90%, to the fluidized bed at multiple points from the bottom of the boiler.

A purpose of the invention is to obtain a homogeneous fuel-air mixture by feeding the humid sludge, which is being fed to the fluidized bed, from the bottom and from multiple points.

Another purpose of the invention is to achieve higher combustion efficiency by means of feeding the humid sludge to the fluidized bed from the bottom and from multiple points. Another purpose of the invention is to provide lower fuel consumption (secondary fuel; CH4, C2H6...etc.) due to high combustion efficiency.

Another purpose of the invention is to eliminate the need for drying, which is used in other methods for burning the sludge, by means of feeding the humid sludge from the bottom at multiple points.

Another purpose of the invention is to provide feeding of the waste sludge to the fluidized bed from under the sand level.

Another purpose of the invention is to use the method in different types of fluidized beds including the bubbling and circulating type fluidized bed systems.

In order to achieve all the advantages which will be understood from the above- mentioned and the detailed description below, the present invention is a sludge feeding mechanism which is used in the fluidized bed combustion boilers comprising a combustion chamber, a gas feeding apparatus, a bed area and sand, with the purpose of feeding it with industrial, domestic or mix-type sludges having viscosity varying between sixty percent and ninety percent humidity rate, comprising feed inlets opening on the bed area which is under the bed level for providing feed of fluidized bed combustion boiler; feed members which enable the sludge to be sent into the bed area by means of mentioned feed inlets, transfer members which enable the sludge to be transferred to the mentioned feed member. The structural and characteristic features of the invention and all of the advantages will be understood more clearly with the help of the figures provided in the following and the detailed description written by means of making references to these figures. Therefore, the evaluation should be carried out in consideration of these figures and the detailed description.

Figures Illustrating the Invention In order to better understand the embodiment and advantages of the invention together with the additional components, it should be evaluated together with the figures described in the following.

Figure-1 ; Perspective view of the mechanism for feeding sludge to the fluidized bed combustion boiler as the subject of the invention.

Figure-2; Two-dimensional side view of the mechanism for feeding sludge to the fluidized bed combustion boiler as the subject of the invention.

Figure-3; Two-dimensional front view of the mechanism for feeding sludge to the fluidized bed combustion boiler as the subject of the invention.

Figure-4; Detailed perspective view of the mechanism for feeding sludge to the fluidized bed combustion boiler as the subject of the invention.

Figure-5; Two-dimensional, front cross-section view of the mechanism for feeding sludge to the fluidized bed combustion boiler as the subject of the invention.

Figure-6; Table representation of the mechanism for feeding sludge to the fluidized bed combustion boiler as the subject of the invention.

Part References

100- Sludge feed mechanism

101 - Combustion chamber

102- Bed area

103- Bed level

104- Feed inlets

105- Transfer member

106- Feed member

107- Gas feeding apparatus

108- Sand

A- Filling the sand

B- Feeding the air and natural gas

C- Pleating the sand

D- Feeding the sand with sludge

E- Burning the sludge in the bed area

F- Continuing the burning of the sludge in the combustion chamber Detailed Description of the Invention

In Figure-1 , the perspective view of the subject mechanism for feeding sludge to the fluidized bed combustion boiler (100) is shown. The invention enables feeding of the industrial, domestic or mixed type sludges with low or high calorific value, whose humidity rate vary between 60% and 90%, to the fluidized bed at multiple points from the bottom.

In Figure-2, the two-dimensional side view of the mechanism for feeding sludge to the fluidized bed combustion boiler (100) is illustrated. The invention is related to a sludge feed mechanism (100) which is used in the fluidized bed combustion boilers comprising a combustion chamber (101 ), a gas feeding apparatus (107) and a bed area (102), with the purpose of feeding it with the industrial, domestic and mix-type sludges having a particular humidity level and viscosity.

In order to feed the fluidized bed combustion boiler (101 ), there are feed inlets (104) present, opening to the bed area (102) which is under the bed level (103). With the purpose of homogenously distributing the wastewater sludge, there are feed inlets (104) which open on the two side surfaces of the bed area (102) in the same direction with even spaces present. The feed members (106) enable the sludge to be sent into the bed area (102) by means of the feed inlets (104). A pump is chosen as a feed member (106). There are transfer members (105) which enable the sludge to be transferred to the feed member (106). A collector is chosen as the transfer member (105). With the purpose of collecting the wastewater sludge and distributing the homogenously, there are transfer members (105) present, which are connected between the feed members (106) having the same size and a suitable layout for the feed inlets (104) that open in a particular order.

Figure-6 is a table representation of the procedure steps of the mechanism subject to the invention for feeding sludge to the fluidized bed combustion boiler.

The sludge feeding method used in the fluidized bed combustion boilers is as follows: The bed area (102) is filled with sand (108) up to the bed level (103) (A). Then, air and natural gas is fed to the bed area (102) by means of the gas feeding apparatus (107) (B). The sand (108) is heated and mobilized by burning the natural gas in the bed area (102) (C). After the suitable combustion heat is provided in the bed area (102), the waste sludge is fed into the sand (108) from under the bed level (103) to the bed area (102), by means of the sludge feed mechanism (100) (D). The waste sludge is burnt in the bed area (102) (E). The step of burning the sludge is continued in the combustion chamber (101 ) (F). In Figure-3, the front two-dimensional view of the subject mechanism for feeding sludge to the fluidized bed combustion boiler (100) and in Figure-4, the detailed perspective view of the subject mechanism for feeding sludge to the fluidized bed combustion boiler (100) is illustrated. The operating principle of the subject mechanism for feeding sludge to the fluidized bed combustion boiler (100) is as follows:

The waste sludge is transferred to the transfer member (105), which functions as a collector. The collection and homogenous distribution of the sludge is provided by means of the transfer members (105). The wastewater sludge which is transferred to the pumps that are chosen as the feed member (106) by means of the transfer members (105) is sent into the bed area from under the bed level (103) and also the sand level, by means of the feed inlets (104) that are opening up to the side surfaces of the bed area (102). In this manner, a continuous, homogenous and even feeding is provided. The sludge is sent to the gas feeding apparatus (107) by being heated or in the ambient conditions during the feeding, depending on the type of the sludge and the climatic conditions. Since the viscosity of the sludge varies according to its temperature and the pressure, the sludge is provided as heated to the system in some cases, in order to prevent blockage and increase efficiency.