JP2008038014A - Apparatus for purifying gas and method, gasification system, gasification power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for purifying a gas, reducing the quantity of a used sulfur-removing agent and improving acidic gas-removing efficiency and sulfur component-removing efficiency, to provide a method therefor, to provide a gasification system using the same, and to provide a gasification power generation system using the same. <P>SOLUTION: The gasification power generation system comprises a temperature-decreasing tower 17 for cooling a high temperature reformed gas 14 reformed in a reformer 15 and supplying a liquid alkali agent 16 to neutralize an acidic gas in the reformed gas 14, the first dust collector 20 for collecting soot and dust in the temperature-decreased cooling gas 18, the second dust collector 23 for supplying a sulfur-removing agent 22 into a flue 21 for supplying the acidic gas-removed cooling gas 18 on the rear flow side of the first dust collector 20 to form the accumulated layer of the supplied sulfur-removing agent 22, a moisture-decreasing apparatus 25 for decreasing moisture in the purified gas 24 obtained by removing the acidic gas component and the sulfur component in the gas, a gas holder 27 for storing the moisture-decreased purified gas 26, and a gas engine or the like 29 for using the gas stored in the gas holder 27 to generate power. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gas purification apparatus and method for efficiently removing, for example, an acidic gas component and an S component such as hydrogen sulfide in gas obtained by gasifying biomass or the like, and a gasification system and a gasification power generation system using the same.

  In order to recover energy from organic waste such as municipal waste, sewage sludge, industrial waste, etc., gas conversion technology that gasifies waste by pyrolysis to obtain fuel gas (gasification gas) is environmental conservation And it is attracting attention from the viewpoint of resource saving.

As a system of this gas conversion technology, there is a system that obtains clean CO, H ₂ rich gas containing no soot by adding water vapor to waste, gasifying at 400 to 900 ° C., and further cracking at 900 to 1500 ° C. Has been developed. In this system, a gasifying agent (steam, oxygen) is supplied at a high temperature to reduce the partial combustion ratio to obtain a gas with a high calorific value, and this gas (fuel gas) generates power with a power generator. (Patent Document 1).

  Since the gasification gas contains a very small amount of sulfur (S) component, it must be desulfurized. Conventionally, when desulfurizing with a high-temperature gas, it has been proposed to spray iron oxide powder using a ceramic filter (Patent Document 2).

  In order to remove hydrogen sulfide, hydrogen chloride, etc. present in the biomass gasification gas, a desulfurizing agent and an acid gas neutralizing agent are supplied immediately after the high-temperature gas is cooled and immediately before the dust is collected by the dust collector. It has been proposed to remove S components such as hydrogen sulfide and acidic gases such as hydrogen chloride (Patent Document 3).

JP 2002-38164 A Japanese Patent Laid-Open No. 64-134028 JP 2005-239905 A

  However, in the proposal of Patent Document 3, for example, when the dust collector as in the configuration of FIG. 3 is a two-column type, the powdery acid gas neutralizing agent is supplied into the flue after being cooled once by the cooling device. Even if the acid gas can be removed, the powdered alkaline agent cannot remove hydrogen sulfide, and the amount of the de-S agent supplied before the dust collector on the downstream side increases. There is a problem.

  In view of the above problems, the present invention reduces the amount of de-S agent used, improves the gas gas removal efficiency and the S component removal efficiency, and a gas purification system and gas using the same. It is an object to provide a power generation system.

  A first invention of the present invention for solving the above-described problems is a reforming furnace for reforming a high-temperature product gas containing an acidic gas obtained by gasifying a raw material and hydrogen sulfide into a reformed gas, and the modified A temperature-decreasing tower for reducing the temperature of the gas and supplying a liquid alkaline agent in a semi-dry state, and a first filtration membrane for collecting dust in the cooled gas. A powder for removing the hydrogen sulfide in a first dust collector formed by forming a deposition layer of the alkaline agent on the surface of the first filtration membrane and a flue on the downstream side of the first dust collector A second dust collector comprising a second filtration membrane that forms a deposited layer of the supplied de-S agent, and an acidic gas component and sulfidation in the cooling gas A gas purification apparatus comprising: a dehumidifying device that dehumidifies the purified gas from which hydrogen has been removed.

  According to a second aspect of the present invention, there is provided the gas purification apparatus according to the first aspect, further comprising a dehumidifying device for dehumidifying the purified gas from which the acidic gas component and hydrogen sulfide in the cooling gas have been removed.

  A third invention is the gas purification apparatus according to the first or second invention, wherein the alkali agent is sprayed in a mist form.

  A fourth invention is the gas purification apparatus according to any one of the first to third inventions, wherein a part of waste water recovered from the dehumidifier is used for the temperature reducing tower.

  According to a fifth invention, in any one of the first to fourth inventions, a heating device is interposed between the first dust collector and the second dust collector, and the second dust collector is obtained. The gas purifier is characterized in that the gas temperature to be sent is higher than that of the first dust collector.

  A sixth invention provides the first analyzer according to any one of the first to fifth inventions, wherein the first analyzer that measures the amount of acidic gas components in the gas is provided on the downstream side of the first dust collector. According to the acid gas amount, an acid gas neutralizing agent is supplied, and a second analyzer for measuring the amount of S component in the gas is provided on the downstream side of the second dust collector, The gas purification apparatus is characterized in that a de-S agent is supplied according to the amount of the S component.

  A seventh invention is the gas purification apparatus according to any one of the first to sixth inventions, wherein the first dust collector and the second dust collector are integrated.

  According to an eighth invention, in the first invention, the de-S agent is at least one of zinc oxide, iron oxide, zinc / iron compound, nickel oxide, copper oxide, cobalt oxide, molybdenum oxide, activated carbon, or a mixture thereof. There exists in the gas purification apparatus characterized by.

  According to a ninth aspect of the present invention, there is provided a gasification system comprising the gas purification device according to any one of the first to eighth aspects.

  A tenth aspect of the invention is a gasification power generation system including any one of the first to eighth gas purification apparatuses.

  In an eleventh aspect, in the ninth aspect, the gasification furnace for obtaining high-temperature gas is any one of a biomass gasification furnace, a garbage gasification furnace, a sewage sludge gasification furnace, and a coal gasification furnace. The gasification system is featured.

  In a twelfth aspect according to the tenth aspect, the gasification furnace for obtaining high-temperature gas is any one of a biomass gasification furnace, a garbage gasification furnace, a sewage sludge gasification furnace, and a coal gasification furnace. The gasification power generation system is featured.

  In a thirteenth aspect of the invention, a mist-like alkaline agent is supplied to a temperature reducing field for reducing a high temperature gas containing an acid gas and a sulfur (S) component, and the cooled gas is collected by the first dust collector. And removing a part of the S component, and then supplying a de-S agent to remove the S component by the second dust collector. It is in.

  In a fourteenth aspect based on the thirteenth aspect, the temperature of the first dust collector is 180 ° C. or lower, and the temperature of the second dust collector is higher than the gas temperature exiting the first dust collector. The gas purification method is characterized in that the temperature is 20 ° C. or higher.

  A fifteenth aspect of the invention is a gas purification method according to the thirteenth or fourteenth aspect of the invention, wherein a purification gas is used for spraying the de-S agent.

  A sixteenth invention is the gas purification method according to any one of the thirteenth to fifteenth inventions, wherein the unreacted de-S agent is reused.

  According to the present invention, since the liquid alkaline agent is supplied to the space in the temperature reducing tower for reducing the temperature of the high temperature gas, the reaction removal efficiency is improved by reacting with the acidic gas in a semi-dry state, and a part of hydrogen sulfide Will be removed. Thereby, the adverse effect of the acidic gas of the desulfurization agent supplied on the rear stage side is hardly affected, the supply amount can be reduced, and the system efficiency can be improved.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

The gas purification apparatus according to the present invention will be described in detail.
FIG. 1 is a schematic diagram of a gasification system having a gas purification apparatus according to a first embodiment. As shown in FIG. 1, a gasification system 10A according to the present embodiment includes a gasification furnace 13 that gasifies a raw material 11 such as biomass to obtain a high-temperature product gas 12, and steam-reforms the high-temperature product gas 12. The reforming furnace 15 for making the reformed gas 14 rich in CO and H ₂ components, and reducing the temperature of the reformed gas 14 and supplying the liquid alkaline agent 16 in a semi-dry state, Is provided with a temperature-decreasing tower 17 for neutralizing the acid gas and a first filtration membrane 20a for collecting the dust in the cooled cooling gas 18, and the alkali on the surface of the first filtration membrane 20a. Smoke for supplying a first dust collecting device 20 formed with a deposition layer (not shown) of the agent 16 and a cooling gas 18 from which the acid gas on the downstream side of the first dust collecting device 20 has been removed. A de-S agent 22 is supplied into the road 21, and the supplied de-S agent 22 is stacked. Dehumidification for dehumidifying the second dust collector 23 having a second filter membrane 23a for forming a layer (not shown) and the purified gas 24 from which the acidic gas component and S component in the cooling gas have been removed An apparatus 25, a gas holder 27 for storing the dehumidified dehumidified purified gas 26, and a gas engine (G / E) 29 that supplies the power generation using the stored gas 28 stored in the gas holder 27 are provided. Is. A heat recovery device is installed on the downstream side of the reforming furnace 15 as necessary.

In the present invention, the product gas 12 is a gas having a small O ₂ component obtained by pyrolyzing a raw material that is a gasification product.
Examples of the raw material 11 of the gasified product include, in addition to biomass, wood chips, garbage, sewage sludge, coal, and the like. These are gasified in the gasification furnace 13, and the gasified gas is reformed to be combustible. The gas is carbon monoxide and hydrogen.
The gas holder 27 may or may not be provided as necessary.

  In the present invention, the alkali agent is sprayed in the mist state from the alkali agent supply device 31 into the internal space of the temperature reducing tower 17 for reducing the temperature of the high-temperature gas reformed in the reforming furnace 15 to change from the liquid state to the dry state. In the process, acid gas and hydrogen sulfide are also removed. Thus, by spraying mist into the tower in a high-temperature field, a gas-liquid contact reaction occurs in a semi-dry state, and not only acidic gas but also part of hydrogen sulfide can be removed. As a result, after cooling with a conventional cooling device, compared with the case of supplying a neutralizing agent that neutralizes the acid gas, the reaction is performed in a high temperature field, and the efficiency of removing the acid gas is improved. Since a part is also removed, the supply amount of the de-S agent 22 supplied on the downstream side of the first dust collector 20 can be reduced.

  Here, in the present invention, the semi-dry state means that the liquid alkali is supplied in the form of a mist to the inside of the tower in the high temperature field of the temperature reducing tower 17 (300 to 1000 ° C. product gas is supplied). It changes from dry to dry.

  Here, as a form of spraying inside the temperature-decreasing tower 17, liquid alkali is supplied into the tower in the form of mist, for example, by a nozzle. For example, a two-fluid nozzle or a rotary atomizer may be used as the nozzle.

  The mist diameter is preferably a maximum particle diameter of 200 μm or less, an average particle diameter of 30 to 70 μm, and preferably 40 to 50 μm. Thereby, contact efficiency with acidic gas improves and it can aim at improvement of removal efficiency of acidic gas in generated gas. Further, it is possible to avoid clogging trouble due to corrosion due to non-evaporation and ash accumulation.

  Further, the equivalent ratio of the alkali agent is preferably less than 6, preferably less than 3, with respect to the acidic gas containing hydrogen sulfide.

Examples of the alkaline agent 16 that neutralizes the acidic gas include an aqueous alkali solution such as an aqueous sodium hydroxide solution, slaked lime slurry, an aqueous sodium bicarbonate solution, or a slurry. Moreover, you may make it supply auxiliary agents, such as diatomaceous earth which protects a filtration membrane.
Here, when sodium hydroxide is used as the alkali agent, it reacts when hydrogen cyanide is present in the product gas, and can be fixed as sodium cyanide and removed by the dust collector 20.
In addition, when calcium hydroxide (slaked lime) is used as the alkaline agent, it is fixed as calcium chloride. Therefore, by using sodium hydroxide, clarification of the recovered ash of the first dust collector 20 is achieved. Trouble caused by can be avoided. In particular, the gasification gas with a large amount of water vapor facilitates the handling of ash.

  The alkali agent dried in the temperature-decreasing tower 17 is carried to the first dust collector 20 through the flue while neutralizing the acid gas in the gas, and the acid gas is passed through the first filtration membrane 20a. A deposition layer of a neutralizing agent is formed, and acidic gas components (HCl, SOx, etc.) in the gas passing there are finally adsorbed and collected.

  Thereby, unlike the case where the alkali agent is supplied into the flue after the temperature reduction as in the conventional case, the alkali agent up to the first dust collector 20 is supplied by supplying it into the temperature reducing tower in the high temperature field. Residence time becomes longer and the acid gas removal efficiency can be improved.

  Here, the first dust collector 20 and the second dust collector 23 collect the dust at a temperature of 150 to 400 ° C., preferably 150 to 200 ° C., and the filter for dust collection is glass fiber, felt, PTFE. A coating filter cloth, a ceramic filter, etc. can be mentioned.

  Alternatively, the alkaline agent may be in a pellet state and separately charged into the gasification furnace 13 or the reforming furnace 15 to remove the acid gas.

In addition to hydrogen sulfide (H ₂ S), the S component contained in the product gas includes sulfides such as COS or sulfur oxides such as SO, SO ₂ , SO ₃ , SO ₄ , and S ₂ O _3. Can be mentioned.

  Examples of the de-S agent 22 in the present invention include zinc oxide, iron oxide, zinc / iron compounds, transition metal oxides such as nickel, copper, activated carbon, zeolite and the like, and zinc oxide is particularly preferable. This is because when it reacts with hydrogen sulfide, it is more excellent in reactivity and cost than other de-S agents. The de-S agent 22 is sprayed in the flue 21 in powder form from the de-S agent supply device 32. The purified gas 24 may be used for spraying the de-S agent.

The de-S agent 22 is in the form of powder and may be several tens of μm to several hundreds of μm. Thereby, a contact area with S component increases and reaction efficiency improves. As a result, the utilization rate and the removal efficiency are improved.
Further, the equivalent ratio of the de-S agent 22 is less than 4, preferably less than 3.

The dust 33 collected by the first dust collector 20 is removed from the first filtration membrane 20a by reverse cleaning after a predetermined time, and is separately collected and removed.
Further, ZnS or the like 34 collected by the second dust collector 23 is removed from the second filtration membrane 23a by reverse cleaning after a predetermined time, and is separately collected and removed.

  The dehumidifying device 25 may be a dehumidifying method based on either an indirect heat exchange type or a direct heat exchange type, but is preferably an indirect heat exchange type device with less waste water.

  The power generation equipment is not limited to a gas engine, and can be applied to gas purification in various power generation devices that can generate power using gas such as a gas turbine or a fuel cell.

  Further, in the present embodiment, an example in which the gas purification apparatus in the gasification power generation system is applied has been described. However, the present invention is not limited to this, for example, by reforming gasification gas from biomass to methanol or the like It can also be applied to a system that obtains

  FIG. 2 is a schematic diagram of a gasification system having a gas purification apparatus according to a second embodiment. The same members as those of the apparatus of the first embodiment shown in FIG. As shown in FIG. 2, the gasification system 10 </ b> B according to the present embodiment supplies a part of the waste water 35 discharged from the dehumidifier 25 to the temperature reducing tower 17 for reuse in the system of the first embodiment. Is. Thereby, the amount of waste water can be reduced.

  FIG. 3 is a schematic diagram of a gasification system having a gas purification apparatus according to a third embodiment. The same members as those of the apparatus of the first embodiment shown in FIG. As shown in FIG. 3, the gasification system 10 </ b> C according to the present embodiment is configured such that, in the system of the first embodiment, the gas is connected to the flue 21 that connects the first dust collector 20 and the second dust collector 23. A heating device 41 is provided to raise the temperature of the gas from the first dust collector 20.

  And the gas temperature of the cooling gas 18 sent to the 1st dust collector 20 is adjusted so that it may become 180 degrees C or less. This is because the removal efficiency of acid gas is improved as the temperature is lower. In this case as well, the temperature is not lowered to 100 ° C. or lower because of the acid dew point.

  By raising the temperature of the gas once cooled by the heating device 41 to 20 ° C. or higher than the gas temperature supplied from the first dust collector 20, the reaction efficiency of the de-S removal reaction is improved. ing.

FIG. 4 is a schematic diagram of a gasification system having a gas purification apparatus according to a fourth embodiment. The same members as those of the apparatus of the first embodiment shown in FIG. As shown in FIG. 4, the gasification system 10 </ b> D according to the present embodiment is the first system that measures the acidic gas component in the purified gas discharged from the first dust collector 20 in the system of the first embodiment. An analyzer 51 and a second analyzer 52 that measures the S component (H ₂ S, SOx) in the purified gas discharged from the second dust collector 23 are provided. The analysis information of the first analysis device 51 and the second analysis device 52 is processed by an arithmetic device (not shown), and a control signal is sent so as to control the supply of the alkaline agent 16 and the desulfurization agent 22. I have to. As a result, the alkaline agent 16 and the desulfurization agent 22 in an appropriate range can always be supplied, and efficient gas purification becomes possible. Moreover, it can be used as an index for determining the dust collection power and the desulfurization agent of the first dust collector 20 and the second dust collector 23.

  FIG. 5 is a schematic diagram of a gasification system having a gas purification apparatus according to a fifth embodiment. The same members as those of the apparatus of the first embodiment shown in FIG. As shown in FIG. 4, the gasification system 10 </ b> E according to the present embodiment is a deposited layer that is periodically removed by, for example, a back cleaning operation in the second dust collector 23 in the system of the first embodiment. A part of the dust containing ZnS or the like 34 is separated by the separation device 36 and returned to the desulfurization agent supply device 32 to reuse the unreacted desulfurization agent 22 in the dust. Thereby, the use cost of an expensive desulfurization agent can be reduced.

  Moreover, as shown in FIG. 6, the wall surface of the 1st dust collector 20 and the 2nd dust collector 23 is put together, and both can be integrated, and it can also be set as the integrated dust collector 50. FIG. Thereby, space saving of the installation space of a dust collector can be achieved.

  In this way, by spraying the alkaline agent 16 into the temperature reducing tower 17 for reducing the temperature of the high temperature gas, the acidic gas in the gas can be efficiently removed and part of the S component can also be removed. Therefore, it is possible to reduce the supply amount of the expensive desulfurization agent 22 supplied on the upstream side of the second dust collecting device 23, and it is possible to improve the reaction efficiency and reduce the processing cost as compared with the conventional case.

  As described above, the gas purification apparatus according to the present invention efficiently removes the acidic gas in the gas by spraying the alkaline agent in a semi-dry state in the temperature reducing tower for reducing the temperature of the high temperature gas. , Part of the S component can also be removed and can be applied to the purification of gasification gas.

1 is a schematic view of a gas purification device according to Example 1. FIG. It is the schematic of the gas purification apparatus concerning Example 2. FIG. It is the schematic of the gas purification apparatus concerning Example 3. FIG. It is the schematic of the other gas purification apparatus concerning Example 4. FIG. It is the schematic of the other gas purification apparatus concerning Example 5. FIG. It is a perspective view of an integrated dust collector.

Explanation of symbols

10A to E Gasification system 11 Raw material 12 Generated gas 13 Gasification furnace 14 Reforming gas 15 Reforming furnace 16 Alkaline agent 17 Temperature reducing tower 18 Cooling gas 19 Filtration membrane 20 First dust collector 21 Flue 22 Desulfurization agent 23 Second dust collector 24 Purified gas 25 Dehumidifier 26 Dehumidified purified gas 27 Gas holder 28 Reserved gas 29 Gas engine (G / E), etc.

Claims (16)

A reforming furnace for reforming a high-temperature product gas containing acid gas and hydrogen sulfide obtained by gasifying a raw material;
A temperature reducing tower that lowers the temperature of the reformed gas and supplies a liquid alkaline agent in a semi-dry state;
A first dust collector comprising a first filtration membrane for collecting the dust in the cooled cooling gas and having a deposited layer of the alkaline agent formed on the surface of the first filtration membrane; ,
A second desulfurization agent that removes the hydrogen sulfide is supplied to the flue on the downstream side of the first dust collector to form a deposited layer of the desulfurization agent supplied. A gas purification device comprising: a second dust collecting device provided with a filtration membrane. In claim 1,
A gas purification apparatus comprising a dehumidifying device for dehumidifying a purified gas from which acidic gas components and hydrogen sulfide in a cooling gas have been removed. In claim 1 or 2,
A gas purification apparatus, wherein the alkali agent is sprayed in a mist form. In any one of Claims 1 thru | or 3,
A gas purification apparatus characterized in that a part of waste water recovered from the dehumidifying apparatus is used in the temperature reducing tower. In any one of Claims 1 thru | or 4,
A heating device is interposed between the first dust collector and the second dust collector, and the gas temperature sent to the second dust collector is higher than that of the first dust collector. A gas purification device characterized. In any one of Claims 1 thru | or 5,
A first analyzer for measuring the amount of acidic gas components in the gas is provided on the downstream side of the first dust collector, and an acidic gas neutralizer is supplied according to the amount of acidic gas. ,
A second analyzer that measures the amount of S component in the gas is provided on the downstream side of the second dust collector, and a de-S agent is supplied according to the amount of S component. Gas purification device to do. In any one of Claims 1 thru | or 6,
The gas purification apparatus, wherein the first dust collector and the second dust collector are integrated. In claim 1,
The gas purifier, wherein the de-S agent is at least one of zinc oxide, iron oxide, zinc / iron compound, nickel oxide, copper oxide, cobalt oxide, molybdenum oxide, activated carbon, or a mixture thereof.   A gasification system comprising the gas purification device according to any one of claims 1 to 8.   A gasification power generation system comprising the gas purification device according to any one of claims 1 to 8. In claim 9,
A gasification system, wherein the gasification furnace for obtaining high-temperature gas is any one of a biomass gasification furnace, a garbage gasification furnace, a sewage sludge gasification furnace, and a coal gasification furnace. In claim 10,
A gasification power generation system characterized in that the gasification furnace for obtaining high-temperature gas is any one of a biomass gasification furnace, a garbage gasification furnace, a sewage sludge gasification furnace, and a coal gasification furnace.   A mist-like alkaline agent is supplied to a temperature-reduction field that reduces the temperature of the high-temperature gas containing the acid gas and sulfur (S) component, and the cooled gas is collected by the first dust collector, A gas purification method comprising removing an acid gas, removing a part of an S component, then supplying a de-S agent, and removing the S component with a second dust collector. In claim 13,
The temperature of the first dust collector is 180 ° C. or less, and the temperature of the second dust collector is 20 ° C. or more higher than the gas temperature exiting the first dust collector. Gas purification method. In claim 13 or 14,
A gas purification method, wherein a purification gas is used for spraying the de-S agent. In any one of Claims 13 thru | or 15,
A gas purification method characterized by reusing the unreacted desulfurization agent.

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