FIELD OF THE INVENTION

The present invention relates to a filtration system and method for filtering super-hot producer gases with temperature over 500?C coming from the downstream of the gasifier system without decreasing the gas temperature. More particularly it relates to an automatic filtration system and method for filtering super-hot producer gases coming from the downstream of the gasifier system while keeping gas temperature stable and high.

BACKGROUND OF THE INVENTION

High temperature (temperature over 500?C) Producer gas coming from Coal Gasifier downstream contain volatile matter in gaseous state. This gas is contaminated with coal dust and suspended particulate matter which can choke the gasifier downstream duct and other equipments like valves and burners. Thus, this contamination needs to be taken care of making sure that temperature of gas does not decrease.

For low coal consumption in the Coal Gasifier, this gas should be fed in the furnace for combustion over 400?C, to make the combustion process more efficient as the calorific value of volatile matter would also be used as combustion fuel along with producer gas thus increasing the calorific value of Producer Gas. Further, because of the high temperature of Producer Gas (over 500?C) it will have high sensible heat. If hot gas is fed in furnace for combustion the efficiency of the combustion is increased. Thus, making combustion more efficient and user having more economical solutions.

In super-hot gasifier, gas comes out at the temperature 500?C plus and its imperative to keep the temperature high till the gas reaches the burner point for the combustion so that the sensible heat of the gas could be utilized and coal consumption in gasifier could be decreased phonemically.

Further as tar is present in the hot gas in the evaporative state and it is advisable not to let decrease the temperature of gas so that the tar does not flow out of the system.

In convention hot gas filter system comprising of filter media like ceramic bags, candle filter, tubular filter, stone grit, coal, results in decrease of producer gas temperature. It not only results in the tar formation but often results in heavy cost in installing heaters to professionally manage tar. Most of the cases, it results in choking of furnace burner and also duct line.

It also results in increase of coal consumption in gasifier on two counts, first decrease in sensible heat of gas and second, Tar has a calorific value which burns in the furnace along with producer gas with high temperature resulting in high calorific value of producer gas. If this tar comes out of the system, more heat will be required to replace this tar resulting in high coal consumption.

Therefore, such filtration media is required that does not decrease the gas temperature, but in fact keep the gas temperature more stable and higher. Therefore, there is requirement for supplying this filtration media automatically by a filtration system. There is also requirement to take out contaminated filter media from the system automatically.

There is also need to improve the efficiency of the system by eliminating downtime of frequent stopping, cleaning of ducts and/or filter media. Resulting in more saving in terms of time, costs and clean system for the user.

SUMMARY OF THE INVENTION

The main object of the present invention is to provide for a filtration system that does not decrease the gas temperature, but in fact keep the gas temperature more stable and higher.

Another object of the invention is to provide an automatic filtration system that automatically feds filter media from the top of filter and contaminated filter media is taken from the bottom of the system automatically.

Yet another object of present invention is to provide for a filtration media that does not decrease the gas temperature, but in fact keep the gas temperature more stable and higher.

One other object of the invention is to provide for a filter media that is capable of filtering the coal dust and other suspended particulate matter efficiently.

Other object of the invention is to provide for a filter media that could be fed and retrieved from the filter automatically.

Therefore, the invention improves the efficiency of the system, eliminates downtime of frequent stopping and cleaning of ducts and cleaning of filter media. Hence resulting in more saving and clean system for the user.

These and other features, aspects and advantages of the present invention will become better understood with reference to the appending description and drawings.

BRIEF DESCRIPTION OF THE DRAWING

Figure 1 shows the schematic drawing of an automatic filtration system working in tandem with complete gasifier.

DESCRIPTION OF INVENTION

In response to aforementioned, the present invention herein provides for an automatic filtration system that employs high alumina ceramic as filtration media. The high alumina ceramic does do not decrease the gas temperature, but in fact keep the gas temperature more stable and higher. The high alumina ceramic is used in form of pebbles and these balls are automatically fed from the top of filtration system.

The filter is in shape of a cylinder or a cuboid which will intake the filter media from top and take out contaminated filter media from the bottom of the system automatically.

The Fig 1 enclosed is schematic drawing of the complete gasifier and automatic filtration system working in tandem to get the desired results. It shows the following equipments with the following narration.

1. Gasifier (G)
2. Gasifier Coal Hopper (GH)
3. Coal Feeding Gate Valve 1 (GV1)
4. Coal Feeding Gate Valve 2 (GV2)
5. Coal Feeding Gate Valve 3 (GV3)
6. Vapor Drum (G1)
7. Air Blower (G2)
8. Ash Tray (G3)
9. Gasifier Coal Bucket (G4)
10. Water Seal for Gasifier Gas Outlet (WS5)
11. First Water Seal for Filter 1 Gas Inlet (WS1)
12. First Water Seal for Filter 2 Gas Inlet (WS3)
13. Second Water Seal for Filter 1 Gas Outlet (WS2)
14. Second Water Seal for Filter 2 Gas Outlet (WS4)
15. Filter 1 (F1)
16. Filter 1 Hopper (F1H)
17. Media Feeding Gate Valve 1 (F1V1)
18. Media Feeding Gate Valve 2 (F1V2)
19. Media Feeding Gate Valve 3 (F1V3)
20. Media Outlet Gate Valve 1 (F1V4)
21. Media Outlet Gate Valve 2 (F1V5)
22. Media Outlet Gate Valve 3 (F1V6)
23. Filter Media Bucket (FB)
24. Filter Media Divertor (D)
25. Filter 2 (F2)
26. Filter 2 Hopper (F2H)
27. Filter Feeding Gate Valve 1 (F2V1)
28. Filter Feeding Gate Valve 2 (F2V2)
29. Filter Feeding Gate Valve 3 (F2V3)
30. Filter Outlet Gate Valve 1 (F2V4)
31. Filter Outlet Gate Valve 2 (F2V5)
32. Filter Outlet Gate Valve 3 (F2V6)
33. First Pressure Transducer (PT1)
34. Second Pressure Transducer (PT2)

The Super-Hot Producer gas (Over 500?C) Filtration system consists of the following components.

a. Filter hopper
b. Triple Seal high alumina ceramic balls feeding arrangement into the filter.
c. Triple seal contaminated balls extraction system installed under the filter.
d. Water seal (WS1) and Water seal (WS2) before and after the filter respectively in filter no. 1 (F1) and water seal (WS3) & Water seal (WS4) before and after the filter.
e. Pressure Transducer (PT1) and Pressure Transducer (PT2) before and after the filter respectively.
f. Filter 1 (F1) and/or Filter 2 (F2) containing the balls.
g. Skip hoist feeding the filter hopper through divertor (D).

The system is made totally automatic by installing three-way gate valves at the inlet and outlet of the filtering media. The pressure in the filter media is monitored by the pressure transducer in the inlet and outlet of the media. Owing to high differential pressure PLC based automatic system discharges some contaminated high alumina pebbles from the bottom and fresh pebbles are fed from the top.

Coal gas/ Producer Gas (over 500?C) coming out from Coal Gasifier (G) would enter filter no. 1 (F1) or filter no. 2 (F2) which are installed in parallel one standby. When the gas entering in Filter 1 (F1), the filter is filled with high alumina ceramic balls. The pressure of the inlet gas is determined by pressure transducer (PT1) and out let gas is determined by Pressure Transducer (PT2). Filter would work with determined differential pressure (PT1-PT2).

High alumina ceramic balls in the Filter system catches the coal dust and suspended Particulate matter while the gas travels from under the filter to the exit at the upper end of the filter. This coal dust and Suspended Particulate Matter come out automatically with the filter media through the PLC sensing increase in differentiate pressure (PT1-PT2). Thus keeping producer gas (Over 500?C) in the downstream of the Filter totally dust free.

If at any point of time determined, differential pressure goes over the defined valve, PLC automatically senses it and activates ceramic balls to go into the filter from filter 1 hopper (F1H) through a divertor (D) using a skip hoist. Filter media used is high alumina ceramic balls for Super Hot Producer Gas (temperature over 500?C). The balls are fed into the filter from series of triple seal valves which open one after the other in following sequence. Valve F1V1 opens and closes then valve F1V2 opens and closes then F1V3 open and closes. This ensures filter media to enter the filter without producer gas leaking out.

The contaminated high alumina ceramic balls coming out of the system are totally dry. There is not tar clinging onto the balls. These balls can be easily sieved and used back Filter media as there is no clinging of dust to this Filter media. The filter media can be automatically cleaned without human intervention for trouble free, no downtime low & no maintenance operation.

The contaminated filter media which contains only coal dust and suspended particulate matter comes out from triple seal valve arrangement under the filter hopper which work in following sequence valve F1 V4 opens and closes then F1 V5 opens and closes then F1V6 opens and closes. Filter media i.e. contaminated ceramic balls are collected in filter media bucket (FB) and send back to the Filter hopper (F1H) & (F2H) after cleaning for recycling.

The Filter Media is fed by a skip hoist through a diverter (D) into Filter hopper F1H or F2 H whichever is running.

Filter no. 2 (F2) will operates as alternate to Filter No. 1 (F1) only if Filter 1 (F1) requires periodic maintenance or cleaning. In such case water seal (WS1) and Water seal (WS2) would be filled by water. Water Seal (WS3) and Water seal (WS4) would be emptied by water. This procedure will bypass filter 1 (F1) and Filter 2 (F2) it would be in operation. Filter 2 (F2) would work in same manner as described for Filter F1.

The Filter System within the inlet and outlet duct would be totally insulated with high quality insulation material so that there is no decrease in temperature of gas because of heat radiation.

The PLC, Scada system and the feed backs to the automatic valves F1V1, F1V2, F1V3, F1V4, F1V5 & F1V6 alternating F2V1, F2V2, F2V3, F2V4, F2V5 & F2V6 work in tandem after signal received from the difference in pressure transducer (PT1-PT2).

It is imperative to note here that any gasifier whose outlet gas temperature is less than 350?C will not be able to benefit from this technology as tar will deposit and choke in the filtration system itself.

Further this filtration system is a revelation for Super Hot Producer Gas coming out of the gasifier (above 500?C) as the user would benefit on 3 counts.

a) Usage of sensible heat of gas.
b) Usage of Tar Calorific value as no tar comes out of the system.
c) No choking in downstream of filter.

It is imperative to note here that any gasifier whose outlet gas temperature is less than 350?C will not be able to benefit from this technology as tar will deposit and choke in the filtration system itself.

As can be seen in Fig 1, the automatic filtration system for filtering super-hot producer gases of the gasifier system consists of: a filter hopper; two filters (F1, F2) installed in parallel and working on determined differential pressure and containing high alumina ceramic balls; triple seal feeding arrangement for feeding high alumina ceramic balls into the filter; triple seal extraction system for extracting contaminated balls installed under the filter; first (WS1/WS3) and second water seals (WS2/WS4) installed before and after each of the filters; first pressure Transducer (PT1) installed before the filter to monitor pressure of the inlet gas; second pressure Transducer (PT2) installed after the filter to monitor pressure of the out let gas; and skip hoist for feeding the high alumina ceramic balls into filter hopper (F1H, F2H) through a divertor (D); wherein the coal gas/ producer Gas with temperature over 500?C coming out from Coal Gasifier (G) with coal dust and suspended particulate matter would enter first or second filter (F1, F2) and the said filter is filled with high alumina ceramic balls, the high alumina ceramic balls in the filter catches the coal dust and suspended particulate matter and the producer gas travels from under the filter to the exit at the upper end of the filter dust free, and due to high differential pressure the system discharges the high alumina ceramic balls contaminated with coal dust and suspended particulate matter from the bottom and fresh high alumina ceramic balls are fed from the top.

In one embodiment of the invention, PLC automatically senses variance in differential pressure over the defined valve, and activates high alumina ceramic balls to go into the filter from filter 1 hopper (F1H).

In another embodiment of the invention, the system consists of three-way gate valves installed at the inlet and outlet of the filtering media for feeding high alumina ceramic balls into the filter.

In a further embodiment of the invention, the triple seal valves open one after the other in a sequence to ensure filter media to enter the filter without producer gas leaking out and exit of the contaminated filter media.

In a further embodiment of the invention, the system consists of a filter media bucket (FB) to collect the filter media and send back to the Filter hopper (F1H, F2H) after cleaning for recycling.

In a further embodiment of the invention, the second filter (F2) operates as alternate to first filter (F1) during periodic maintenance or cleaning.

In a further embodiment of the invention, during periodic maintenance or cleaning water seal (WS1) and Water seal (WS2) would be filled with water to bypass the first filter 1 (F1) and Water Seal (WS3) and Water seal (WS4) would be emptied of water to enable the second filter (F2) to come in operation.

In a further embodiment of the invention, the filter system within within the inlet and outlet duct is insulated with high quality insulation material to avoid any decrease in temperature of gas because of heat radiation.

In a further embodiment of the invention, PLC, Scada system and the feed backs to the Filter feeding gate valves (F1V1, F1V2, F1V3, F2V1, F2V2, F2V3) and Filter outlet gate valves (F1V4, F1V5, F1V6, F2V4, F2V5, F2V6) work in tandem after signal received from the difference in pressure transducer (PT1, PT2).

As can be seen in Fig 1, the method for filtering super-hot producer gases of the gasifier system consists of providing an automatic filtration system having one or more filters (F1, F2) and working on determined differential pressure; making the coal gas/ producer Gas with temperature over 500?C coming out from Coal Gasifier (G) with coal dust and suspended particulate matter to enter the filter; feeding the high alumina ceramic balls into filter hopper (F1H, F2H) through a divertor (D) using skip hoist, which in turn feeds the said filter; monitoring the pressure using first pressure Transducer (PT1) and second pressure Transducer (PT2) installed before the filter and after the filter to monitor pressure of the inlet and out let gas respectively; catching the coal dust and suspended particulate matter in the filters using high alumina ceramic balls and allowing the producer gas to exit at the upper end of the filter dust free; and discharging the high alumina ceramic balls contaminated with coal dust and suspended particulate matter from the bottom of filter due to high differential pressure using triple seal extraction system.

In one embodiment of invention, the contaminated ceramic balls are collected in dry bucket/ filter media bucket (FB) and send back to the Filter hopper (F1H, F2H) after cleaning for recycling.

In another embodiment of invention, fresh high alumina ceramic balls are fed from the top of the filter using said high differential pressure.

In a further embodiment of invention, the three-way gate valves installed at the inlet and outlet of the filtering media for feeding high alumina ceramic balls into the filter, opens one after the other in a sequence to ensure filter media to enter the filter without producer gas leaking out and exit of the contaminated filter media.

In a further embodiment of invention, the second filter (F2) operates as alternate to first filter (F1) during periodic maintenance or cleaning and water seal (WS1) and Water seal (WS2) is filled with water to bypass the first filter 1 (F1) and Water Seal (WS3) and Water seal (WS4) would be emptied of water to enable the second filter (F2) to come in operation.

The description herein is one of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The present invention has been described with respect to particularly preferred embodiments. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention.
It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.

We claim:

1. An automatic filtration system for filtering super-hot producer gases of the gasifier system consisting of:
a filter hopper;
two filters (F1, F2) installed in parallel and working on determined differential pressure and containing high alumina ceramic balls;
triple seal feeding arrangement for feeding high alumina ceramic balls into the filter;
triple seal extraction system for extracting contaminated balls installed under the filter;
first (WS1/WS3) and second water seals (WS2/WS4) installed before and after each of the filters;
first pressure Transducer (PT1) installed before the filter to monitor pressure of the inlet gas;
second pressure Transducer (PT2) installed after the filter to monitor pressure of the out let gas; and
skip hoist for feeding the high alumina ceramic balls into filter hopper (F1H, F2H) through a divertor (D);
wherein the coal gas/ producer Gas with temperature over 500?C coming out from Coal Gasifier (G) with coal dust and suspended particulate matter would enter first or second filter (F1, F2) and the said filter is filled with high alumina ceramic balls, the high alumina ceramic balls in the filter catches the coal dust and suspended particulate matter and the producer gas travels from under the filter to the exit at the upper end of the filter dust free, and due to high differential pressure the system discharges the high alumina ceramic balls contaminated with coal dust and suspended particulate matter from the bottom and fresh high alumina ceramic balls are fed from the top.

2. The automatic filtration system as claimed in claim 1, wherein PLC automatically senses variance in differential pressure over the defined valve, and activates high alumina ceramic balls to go into the filter from filter 1 hopper (F1H).

3. The automatic filtration system as claimed in claim 1, wherein the system consists of three-way gate valves installed at the inlet and outlet of the filtering media for feeding high alumina ceramic balls into the filter.

4. The automatic filtration system as claimed in claim 3, wherein the triple seal valves open one after the other in a sequence to ensure filter media to enter the filter without producer gas leaking out and exit of the contaminated filter media.

5. The automatic filtration system as claimed in claim 1, wherein the system consists of a filter media bucket (FB) to collect the filter media and send back to the Filter hopper (F1H, F2H) after cleaning for recycling.

6. The automatic filtration system as claimed in claim 1, wherein the second filter (F2) operates as alternate to first filter (F1) during periodic maintenance or cleaning.

7. The automatic filtration system as claimed in claim 6, wherein during periodic maintenance or cleaning water seal (WS1) and Water seal (WS2) would be filled with water to bypass the first filter 1 (F1) and Water Seal (WS3) and Water seal (WS4) would be emptied of water to enable the second filter (F2) to come in operation.

8. The automatic filtration system as claimed in claim 1, wherein the filter system within the inlet and outlet duct is insulated with high quality insulation material to avoid any decrease in temperature of gas because of heat radiation.

9. The automatic filtration system as claimed in claim 1, wherein the PLC, Scada system and the feed backs to the Filter feeding gate valves (F1V1, F1V2, F1V3, F2V1, F2V2, F2V3) and Filter outlet gate valves (F1V4, F1V5, F1V6, F2V4, F2V5, F2V6) work in tandem after signal received from the difference in pressure transducer (PT1, PT2).

10. A method for filtering super-hot producer gases of the gasifier system consisting of:
providing an automatic filtration system having one or more filters (F1, F2) and working on determined differential pressure;
making the coal gas/ producer Gas with temperature over 500?C coming out from Coal Gasifier (G) with coal dust and suspended particulate matter to enter the filter;
feeding the high alumina ceramic balls into filter hopper (F1H, F2H) through a divertor (D) using skip hoist, which in turn feeds the said filter;
monitoring the pressure using first pressure Transducer (PT1) and second pressure Transducer (PT2) installed before the filter and after the filter to monitor pressure of the inlet and out let gas respectively;
catching the coal dust and suspended particulate matter in the filters using high alumina ceramic balls and allowing the producer gas to exit at the upper end of the filter dust free; and
discharging the high alumina ceramic balls contaminated with coal dust and suspended particulate matter from the bottom of filter due to high differential pressure using triple seal extraction system.