WO2021111671A1 - Gas purification method and gas purification device - Google Patents

Abstract

This gas purification method includes: a step (dust removing step S110) for removing solid particles contained in a gas; a step (water cleaning step S120) for bringing the gas having the solid particles removed therefrom into contact with a first cleaning liquid having a melting point lower than that of a removal substance contained in the gas; and a step (oil cleaning step S130) for, after executing the step for bringing the gas into contact with the first cleaning liquid, bringing the gas that had been already in contact with the first cleaning liquid into contact with a second cleaning liquid having a higher affinity with the removal substance as compared with the first cleaning liquid.

Description

Gas refining method and gas refining equipment

This disclosure relates to a gas purification method and a gas purification apparatus. This application claims the benefit of priority under Japanese Patent Application No. 2019-217726 filed on December 2, 2019, the contents of which are incorporated herein by reference.

Exhaust gas treatment equipment equipped with a bug filter and an oil scrubber is disclosed as a technique for refining gas (for example, Patent Document 1). In the technique of Patent Document 1, the bug filter removes dust from the gas. The oil scrubber removes organic compounds in the gas by bringing the cleaning oil into contact with the gas from which the dust has been removed by the bug filter. The oil scrubber comprises a gas-liquid contact portion that brings the cleaning oil into contact with the gas. The cleaning oil in contact with the gas circulates in the oil scrubber by being supplied again to the gas-liquid contact portion.

Japanese Unexamined Patent Publication No. 2006-21187

The oil scrubber removes organic compounds from the gas by dissolving organic compounds such as tar, olefins, and organic halides contained in the gas in the cleaning oil. However, when heavy tar having a relatively high melting point is dissolved in the cleaning oil, the viscosity of the cleaning oil increases.

Then, it becomes difficult to circulate the cleaning oil to the oil scrubber, and the oil scrubber cannot be operated. Therefore, it becomes necessary to frequently replace the cleaning oil with new oil, which causes a problem that the cost increases. Therefore, there is a demand for the development of a technology capable of purifying gas at low cost.

In view of such problems, the present disclosure aims to provide a gas purification method capable of purifying gas at low cost and a gas purification apparatus.

In order to solve the above problems, the gas purification method according to one aspect of the present disclosure is based on the steps of removing solid particles contained in the gas, the gas from which the solid particles have been removed, and the melting point of the removed substance contained in the gas. After performing the steps of contacting the low-temperature first cleaning liquid and the first cleaning liquid, the gas brought into contact with the first cleaning liquid has a higher affinity for the removing substance than the first cleaning liquid. Includes a step of contacting with a cleaning solution.

Further, the flow rate of the first cleaning liquid may be determined according to the temperature of the gas from which the solid particles have been removed after the step of removing the solid particles has been performed.

Further, the first cleaning liquid may contain at least water, and the second cleaning liquid may contain at least oil.

In order to solve the above problems, the gas purification apparatus according to one aspect of the present disclosure includes a dust removing unit for removing solid particles contained in the gas, a gas from which the solid particles have been removed by the dust removing unit, and a removal contained in the gas. The first scrubber that contacts the first cleaning liquid that is lower than the melting point of the substance, the gas treated by the first scrubber, and the second cleaning liquid that has a higher affinity for the removing substance than the first cleaning liquid are brought into contact with each other. It is equipped with 2 scrubbers.

Further, the first cleaning liquid may contain at least water, and the second cleaning liquid may contain at least oil.

Further, the gas purification apparatus may include a water supply unit that supplies the wastewater generated by the second scrubber to the first scrubber.

Further, the gas purification apparatus may be provided with a tar decanter for storing the wastewater generated in the first scrubber and the wastewater generated in the second scrubber.

Further, the gas purification apparatus may be equipped with equipment that utilizes the removed substance removed from the gas in the first scrubber.

According to the present disclosure, it is possible to purify gas at low cost.

FIG. 1 is a diagram illustrating a gasification gas production apparatus. FIG. 2 is a diagram illustrating a gas purification apparatus. FIG. 3 is a flowchart illustrating a processing flow of the gas purification method. FIG. 4 is a diagram illustrating an oil circulation portion and a regeneration portion according to a modified example.

The embodiments of the present disclosure will be described in detail with reference to the accompanying drawings below. The dimensions, materials, other specific numerical values, etc. shown in such an embodiment are merely examples for facilitating understanding, and do not limit the present disclosure unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are designated by the same reference numerals to omit duplicate description, and elements not directly related to the present disclosure are omitted from the illustration. To do.

[Gasification gas production device 100]
FIG. 1 is a diagram illustrating a gasification gas production apparatus 100. In FIG. 1, solid arrows indicate the flow of solids (fluid media, raw materials, and residues) and liquids (water). Further, in FIG. 1, the broken line arrow indicates the flow of gas (water vapor, gasified gas, air, and combustion exhaust gas).

As shown in FIG. 1, the gasification gas production apparatus 100 includes a combustion furnace 110, a cyclone 120, a heat exchanger 130, a bag filter 140, a gasification furnace 150, a cyclone 160, and a heat exchanger 170. , And a gas purification apparatus 200.

The gasification gas production apparatus 100 uses a fluidized bed as a fluidized medium to gasify raw materials to produce gasified gas (synthetic gas). The raw material is, for example, a solid raw material such as coal (brown coal or the like) or biomass (wood pellets or the like). The gasification gas production apparatus 100 is a circulating fluidized bed type gasification system. That is, the gasification gas production apparatus 100 circulates a flow medium as a heat medium in the combustion furnace 110, the cyclone 120, and the gasification furnace 150. The fluid medium is, for example, a mineral such as silica sand or olivine having a particle size of about 300 μm.

The combustion furnace 110 has a tubular shape. Fuel and a flow medium are introduced into the combustion furnace 110 from the gasification furnace 150, which will be described later, through the pipe 112. The pipe 112 connects the lower part of the combustion furnace 110 and the gasification furnace 150. The combustion furnace 110 burns fuel to heat the flow medium to 600 ° C. or higher and 1000 ° C. or lower. The combustion exhaust gas and the flow medium heated in the combustion furnace 110 are sent to the cyclone 120 through the pipe 114. The pipe 114 connects the upper part of the combustion furnace 110 and the cyclone 120.

The cyclone 120 firmly separates the mixture of the flow medium introduced from the combustion furnace 110 and the combustion exhaust gas through the pipe 114. The high temperature fluid medium separated by the cyclone 120 is introduced into the gasifier 150 through the pipe 122. The pipe 122 connects the bottom of the cyclone 120 and the gasifier 150.

The high temperature fluid medium is fluidized by the fluidized gas (for example, steam) in the gasification furnace 150. Specifically, the gasification furnace 150 includes a storage tank 152 and a steam introduction unit 154. The storage tank 152 stores the flow medium and the raw material.

The water vapor introduction unit 154 introduces water vapor into the storage tank 152. The steam introduction unit 154 includes a wind box 154a and a boiler 154b. The wind box 154a is provided below the storage tank 152. The upper part of the wind box 154a also functions as the bottom surface of the storage tank 152. The upper part of the wind box 154a is composed of a breathable dispersion plate. The boiler 154b produces steam. The boiler 154b is connected to the wind box 154a. The steam generated by the boiler 154b is introduced into the air box 154a. The water vapor introduced into the air box 154a is introduced into the storage tank 152 from the bottom surface (dispersion plate) of the storage tank 152. The boiler 154b introduces water vapor into the air box 154a at a flow velocity capable of forming a fluidized bed of a fluidized medium in the storage tank 152. Therefore, the high temperature fluid medium introduced from the cyclone 120 is fluidized by water vapor. As a result, a fluidized bed of the fluidized medium (for example, a bubble fluidized bed (bubbling fluidized bed)) is formed in the storage tank 152.

Further, the raw material is introduced into the gasification furnace 150 (containment tank 152) through the pipe 122. The introduced raw material is gasified by the heat of the fluid medium at 600 ° C. or higher and 900 ° C. or lower, whereby a gasified gas (synthetic gas) is produced. The gasified gas produced in the gasification furnace 150 is introduced into the cyclone 160 through the pipe 156. The pipe 156 connects the upper part of the gasifier 150 and the cyclone 160.

The cyclone 160 solid-gas separates the gasified gas discharged from the gasification furnace 150. The gasified gas separated by solid air is introduced into the heat exchanger 170 through the pipe 162. The pipe 162 connects the upper part of the cyclone 160 and the heat exchanger 170. Further, the solid matter separated by solid air (fluid medium, residue of raw material, some tar) is introduced into the combustion furnace 110 through the pipe 164 and the pipe 112. The pipe 164 connects the bottom of the cyclone 160 and the pipe 112. In this embodiment, the raw material is also introduced into the pipe 164.

The heat exchanger 170 exchanges heat between the gasified gas solidly separated by the cyclone 160 and steam, high-pressure water, or the like. The heat exchanger 170 recovers the sensible heat of the gasified gas with steam, and sets the outlet temperature of the gasified gas to 150 ° C. or higher and 200 ° C. or lower. The gasified gas cooled by the heat exchanger 170 is introduced into the gas purification apparatus 200 described later through the pipe 172. The specific configuration of the gas purification apparatus 200 will be described in detail later. The pipe 172 connects the heat exchanger 170 and the gas purification device 200 (dust removal unit 210).

As described above, the fluidized medium in the gasification furnace 150 is returned to the combustion furnace 110 through the pipe 112 connecting the gasification furnace 150 and the combustion furnace 110. As described above, in the gasification gas production apparatus 100 according to the present embodiment, the flow medium moves the combustion furnace 110, the cyclone 120, and the gasification furnace 150 in this order, and is introduced into the combustion furnace 110 again. Circulate these.

Further, the residue of the raw material is introduced into the combustion furnace 110 from the gasification furnace 150 through the pipe 112. The residue of the raw material is used as fuel in the combustion furnace 110. The residue of the raw material is the raw material that remains without being gasified in the gasification furnace 150.

Further, the combustion exhaust gas separated by the cyclone 120 is guided to the heat exchanger 130 through the pipe 124. The pipe 124 connects the upper part of the cyclone 120 and the heat exchanger 130. The heat exchanger 130 is, for example, a boiler. The heat exchanger 130 exchanges heat between the combustion exhaust gas separated by the cyclone 120 and water. The heat exchanger 130 cools the combustion exhaust gas and heats (vaporizes) the water.

The bug filter 140 removes the combustion exhaust gas introduced from the heat exchanger 130 through the pipe 132. The pipe 132 connects the heat exchanger 130 and the bug filter 140. The combustion exhaust gas removed by the bag filter 140 is denitrated by a denitration device (not shown). The denitrated combustion exhaust gas is desulfurized by a desulfurization device (not shown). The desulfurized combustion exhaust gas is exhausted to the outside. The denitration device and the desulfurization device may be omitted.

As described above, the gasifier 150 gasifies the raw material in a low temperature range of 600 ° C. or higher and 900 ° C. or lower. Therefore, the gasification gas generated in the gasification furnace 150 contains tar. Although the tar contained in the gasification gas is partially separated by the cyclone 160, most of the tar is introduced into the heat exchanger 170 along with the gasification gas. Further, the gasification gas includes ash derived from a raw material and solid particles (dust) such as a fluid medium.

Therefore, the gasification gas production device 100 includes a gas purification device 200. The gas purification apparatus 200 purifies the gasified gas by removing impurities (tar and solid particles) from the gasified gas. Hereinafter, the gas purification apparatus 200 will be described in detail.

[Gas Purifier 200]
FIG. 2 is a diagram illustrating a gas refining apparatus 200. In FIG. 2, the broken line arrow indicates the flow of the gasified gas. Further, in FIG. 2, the solid arrow indicates the flow of the liquid (first cleaning liquid, drainage, second cleaning liquid, and drainage oil).

As shown in FIG. 2, the gas refining apparatus 200 includes a dust removing unit 210, a water scrubber 220, an oil scrubber 230, a mist separator 240, an attraction fan 250, a tar decanter 260, a tar dispensing facility 270, and a water circulation. A portion 280 and an oil circulation portion 290 are included. The dust remover 210, the water scrubber 220, the oil scrubber 230, and the mist separator 240 communicate with each other. Further, the mist separator 240 is connected to the suction side of the attraction fan 250. Therefore, when the attraction fan 250 is driven, the gasification gas passes through the dust removing unit 210, the water scrubber 220, the oil scrubber 230, and the mist separator 240 in this order.

The dust remover 210 is composed of, for example, one or more of a bug filter, a ceramic filter, and a cyclone. The dust remover 210 is connected to the heat exchanger 170 through the pipe 172. The dust removing unit 210 removes a part of solid particles and tar contained in the gasified gas. The tar contained in the gasification gas includes heavy tar and light tar. Heavy tar has a higher mass density than water. Heavy tar has properties equivalent to or similar to heavy oil. Light tar has a lower boiling point than heavy tar. The light tar contains, as a main component, an aromatic compound having one or two aromatic rings (benzene, toluene, xylene, naphthalene, etc.). The dust remover 210 removes a part of heavy tar.

The gasified gas from which solid particles and a part of heavy tar have been removed by the dust removing unit 210 is introduced into the water scrubber 220 through the pipe 212.

The water scrubber 220 (first scrubber) brings the gasified gas from which the solid particles have been removed by the dust removing unit 210 into contact with the first cleaning liquid. The first cleaning liquid has a temperature lower than the melting point of the heavy tar (removed substance) contained in the gasified gas. The first cleaning liquid is a liquid containing at least water. The water scrubber 220 cools the gasified gas to 80 ° C. or higher and lower than 100 ° C. (for example, about 85 ° C.) by bringing the gasified gas into contact with the first cleaning liquid.

In the present embodiment, the water scrubber 220 includes a main body 220a and a spraying portion 220b. The main body 220a has a tubular shape. A pipe 222 is connected to the upper part of the main body 220a. The pipe 222 connects the water scrubber 220 and the oil scrubber 230. A pipe 282 is connected to the bottom of the main body 220a. The pipe 282 connects the water scrubber 220 and the tar decanter 260. A pipe 212 is connected between the connection point of the pipe 222 in the main body 220a and the connection point of the pipe 282. Therefore, the gasified gas introduced from the pipe 212 rises in the main body 220a and is exhausted from the pipe 222.

The spraying portion 220b is provided between the connection point of the pipe 222 and the connection point of the pipe 212 in the main body 220a. The spraying unit 220b sprays the first cleaning liquid into the main body 220a.

Therefore, the gasified gas comes into contact with the first cleaning liquid in the process of passing (rising) through the main body 220a and is cooled to about 85 ° C. Then, the heavy tar remaining in the gasification gas is condensed and removed from the gasification gas. Then, the gasified gas from which the heavy tar has been removed is introduced into the oil scrubber 230 through the pipe 222. On the other hand, the condensed heavy tar falls to the bottom of the main body 220a together with the first cleaning liquid and is introduced into the tar decanter 260 through the pipe 282.

In this way, the water scrubber 220 can condense heavy tar while maintaining fluidity by cooling the gasified gas to 80 ° C. or higher and lower than 100 ° C. As a result, the water scrubber 220 can move the heavy tar together with the first cleaning liquid to the tar decanter 260 by its own weight. That is, the water scrubber 220 can easily move heavy tar to the tar decanter 260.

In addition, the water scrubber 220 maintains the gasified gas at 80 ° C. or higher. As a result, the water scrubber 220 can avoid a situation in which naphthalene is deposited on the inner wall of the main body 220a.

Ammonia and sulfur oxides (SOx) are dissolved in the first cleaning solution. Therefore, if the gasification gas contains ammonia or sulfur oxides, the water scrubber 220 can remove the ammonia and sulfur oxides from the gasification gas.

The oil scrubber 230 (second scrubber) brings the gasified gas treated by the water scrubber 220 into contact with the second cleaning liquid. The second cleaning solution has a higher affinity for tar (removing substance) than the first cleaning solution. The second cleaning liquid is a liquid containing at least oil. The oil includes, for example, one or more of mineral oil, light oil, biodiesel fuel, and vegetable oil. The oil scrubber 230 dissolves the light tar contained in the gasification gas in the second cleaning liquid by bringing the gasification gas into contact with the second cleaning liquid. As a result, the oil scrubber 230 removes light tar from the gasified gas.

In the present embodiment, the oil scrubber 230 includes a main body 230a, a dispersion portion 230b, and a filling layer 230c. The main body 230a has a tubular shape. A pipe 232 is connected to the upper part of the main body 230a. The pipe 232 connects the oil scrubber 230 and the mist separator 240. A pipe 234 is connected to the bottom of the main body 230a. The pipe 234 connects the oil scrubber 230 and the tar decanter 260. A pipe 292 is connected between the connection point of the pipe 232 and the connection point of the pipe 234 in the main body 230a. The pipe 292 connects the oil scrubber 230 and the pump 294. The pipe 222 is connected between the connection point of the pipe 232 and the connection point of the pipe 292 in the main body 230a. Therefore, the gasified gas introduced from the pipe 222 rises in the main body 230a and is exhausted from the pipe 232.

The dispersion portion 230b is provided between the connection point of the pipe 232 and the connection point of the pipe 222 in the main body 230a. The dispersion unit 230b sprays the second cleaning liquid at a temperature at which the water vapor contained in the gasified gas condenses (for example, 50 ° C. or lower) into the main body 230a.

Therefore, the gasified gas comes into contact with the second cleaning liquid in the process of passing (rising) through the main body 230a. As a result, the light tar contained in the gasified gas is dissolved in the second cleaning liquid. Then, the light tar dissolved in the second cleaning liquid falls to the bottom of the main body 230a.

Further, the gasified gas is cooled by the second cleaning liquid. Then, the water vapor remaining in the gasification gas is condensed and removed from the gasification gas. Then, the condensed water vapor, that is, the condensed water, falls to the bottom of the main body 230a. In addition, the condensed water has a higher mass density than the second cleaning liquid and the exhaust oil containing light tar. Therefore, the condensed water stays below the oil drainage layer at the bottom of the main body 230a. That is, in the main body 230a, the drained oil and the condensed water are separated by sedimentation.

Then, the condensed water (drainage) accumulated at the bottom of the main body 230a is introduced into the tar decanter 260 through the pipe 234. Further, the drainage oil accumulated above the condensed water in the main body 230a is sucked into the pump 294 through the pipe 292.

Further, the gasified gas from which the light tar and water vapor have been removed is introduced into the mist separator 240 through the pipe 232.

The filling layer 230c is provided between the dispersion portion 230b in the main body 230a and the connection point with the pipe 222. The packing layer 230c includes rings, wire mesh, shelves, trays and the like. The packing layer 230c reduces the falling speed of the second cleaning liquid. Since the oil scrubber 230 includes the filling layer 230c, the contact efficiency between the gasification gas and the second cleaning liquid can be improved. Therefore, the oil scrubber 230 can efficiently dissolve the light tar contained in the gasified gas in the second cleaning liquid.

The mist separator 240 removes the mist (second cleaning liquid) contained in the gasified gas. A pipe 242 is connected to the upper part of the mist separator 240. The pipe 242 connects the mist separator 240 and the suction side of the attraction fan 250. A pipe 244 is connected to the bottom of the mist separator 240. The pipe 244 connects the mist separator 240 and the oil scrubber 230 (main body 230a). In the present embodiment, the pipe 242 is connected below the filling layer 230c in the main body 230a. The pipe 232 is connected between the connection point of the pipe 242 in the mist separator 240 and the connection point of the pipe 244. Therefore, the gasified gas introduced from the pipe 232 is exhausted from the pipe 242 after the mist is removed in the mist separator 240. Further, the mist removed from the gasified gas in the mist separator 240 is returned to the oil scrubber 230 through the pipe 244.

The suction fan 250 is connected to the pipe 242 (mist separator 240) on the suction side and to the pipe 252 on the discharge side. The attraction fan 250 sucks the gasification gas (refined gasification gas) from which the mist has been removed by the mist separator 240 and sends it to the gasification gas utilization facility in the subsequent stage through the pipe 252. Gasification gas utilization equipment is power generation equipment such as a gas engine, or equipment for manufacturing chemical products.

The tar decanter 260 stores the wastewater generated in the water scrubber 220 and the condensed water generated in the oil scrubber 230. The tar decanter 260 separates wastewater into a supernatant and a sediment depending on the difference in mass density and particle size. The sediment contains heavy tar.

The tar dispensing equipment 270 is composed of, for example, a screw conveyor. The tar dispensing facility 270 sends out the sediment (heavy tar) separated in the tar decanter 260 to the outside. Heavy tar (removed substance) is used as fuel for combustion equipment (equipment) such as boilers and generators, and is also used for animal protection.

The water circulation unit 280 circulates the first cleaning liquid in the water scrubber 220. The water circulation unit 280 includes pipes 282, 284, 288 and a pump 286. The pipe 284 connects the tar decanter 260 and the suction side of the pump 286. The pipe 288 connects the discharge side of the pump 286 and the spray portion 220b. The pump 286 supplies the supernatant liquid separated in the tar decanter 260 as the first cleaning liquid to the spray unit 220b.

Further, as described above, the condensed water separated by the oil scrubber 230 is introduced into the tar decanter 260. Therefore, the pipe 234, the tar decanter 260, and the water circulation unit 280 function as a water supply unit that supplies the wastewater generated by the oil scrubber 230 to the water scrubber 220.

The oil circulation unit 290 circulates the second cleaning liquid in the oil scrubber 230. The oil circulation unit 290 includes pipes 292 and 296, a pump 294, and a cooling unit 298. As described above, the pipe 292 connects the main body 230a of the oil scrubber 230 and the suction side of the pump 294. The pipe 296 connects the discharge side of the pump 294 and the dispersion portion 230b of the oil scrubber 230. The pump 294 supplies the exhaust oil retained in the main body 230a of the oil scrubber 230 as a second cleaning liquid to the dispersion portion 230b. The cooling unit 298 is provided in the pipe 296. The cooling unit 298 cools the second cleaning liquid. With the configuration including the cooling unit 298, the oil scrubber 230 can efficiently dissolve the light tar contained in the gasified gas in the second cleaning liquid.

[Gas purification method]
Subsequently, a gas refining method using the gas refining apparatus 200 will be described. FIG. 3 is a flowchart illustrating a processing flow of the gas purification method. As shown in FIG. 3, the gas refining method includes a dust removing step S110, a water cleaning step S120, and an oil cleaning step S130. Hereinafter, each step will be described in detail.

[Dust removal step S110]
The dust removing step S110 is a step in which the dust removing unit 210 removes solid particles contained in the gasified gas.

[Water cleaning step S120]
The water cleaning step S120 is a step in which the water scrubber 220 brings the gasified gas from which the solid particles have been removed in the dust removing step S110 into contact with the first cleaning liquid. By carrying out the water washing step S120, heavy tar is removed from the gasified gas.

[Oil cleaning step S130]
The oil cleaning step S130 is a step in which the oil scrubber 230 brings the gasified gas from which the heavy tar has been removed in the water cleaning step S120 into contact with the second cleaning liquid. By carrying out the oil cleaning step S130, the light tar is removed from the gasified gas.

As described above, the gas purification device 200 of the present embodiment and the gas purification method using the gas purification device 200 include a dust removing unit 210. Thereby, the processing load of the water scrubber 220 can be reduced. Therefore, the gas purification apparatus 200 can reduce the size of the water scrubber 220 and the tar decanter 260.

Further, the gas refining device 200 includes a water scrubber 220 and an oil scrubber 230. The conventional technique for purifying a gasified gas using only a water scrubber 220 has a low tar removal rate of about 10% to 25%. On the other hand, the gas refining apparatus 200 can remove heavy tar with a water scrubber 220 and light tar with an oil scrubber 230. Therefore, the gas purification apparatus 200 can efficiently remove tar contained in the gasified gas.

Further, in the conventional technique of purifying the gasification gas only with the oil scrubber 230, not only the light tar but also the heavy tar is dissolved in the second cleaning liquid. Since heavy tar has a high melting point, when it is dissolved in the second cleaning solution, the viscosity of the second cleaning solution increases. Then, it becomes difficult to circulate the second cleaning liquid to the oil scrubber 230, and the oil scrubber 230 cannot be operated. Therefore, in the prior art of purifying the gasified gas only with the oil scrubber 230, the second cleaning liquid had to be changed frequently.

On the other hand, the gas refining device 200 includes a water scrubber 220 in front of the oil scrubber 230. As a result, the oil scrubber 230 brings the gasified gas from which the heavy tar has been removed into contact with the second cleaning liquid. The viscosity of the light tar does not increase as compared with the heavy tar even if it is dissolved in the second cleaning liquid. Therefore, the oil circulation unit 290 can stably circulate the second cleaning liquid to the oil scrubber 230. Therefore, the gas refining apparatus 200 can reduce the frequency of replacement of the second cleaning liquid as compared with the conventional technique including only the oil scrubber 230. As a result, the gas purification device 200 can purify the gasified gas at low cost.

Further, the conventional technique of purifying the gasified gas only with the oil scrubber 230 cannot remove water-soluble impurities. Therefore, in the conventional technique of purifying the gasification gas only with the oil scrubber 230, there is a possibility that the gasification gas utilization equipment in the subsequent stage using the gasification gas may be defective due to water-soluble impurities. On the other hand, since the gas refining apparatus 200 includes the water scrubber 220 in addition to the oil scrubber 230, not only tar but also water-soluble impurities can be removed from the gasification gas. Therefore, the gas refining device 200 can prevent a malfunction of the gasification gas utilization equipment in the subsequent stage using the gasification gas.

Further, the gas refining apparatus 200 is provided with a tar decanter 260. As a result, the gas purification apparatus 200 can separate the heavy tar from the wastewater. Therefore, the gas refining apparatus 200 can effectively utilize heavy tar.

Further, the gas purification device 200 includes a water supply unit (pipe 234, tar decanter 260, and water circulation unit 280). As a result, the gas refining apparatus 200 can utilize the wastewater generated in the oil scrubber 230 in the water scrubber 220. Therefore, the gas purification apparatus 200 can reduce the cost required for the first cleaning liquid.

Further, the gas refining device 200 includes a dust removing unit 210, a water scrubber 220, and an oil scrubber 230. Therefore, the gas refining apparatus 200 can efficiently remove tar from the gasification gas even if the oxidation reforming furnace conventionally used for removing tar contained in the gasification gas is omitted. The oxidation reforming furnace adds oxygen or air to the gasified gas generated in the gasification furnace 150 and burns a part of the gasified gas. Therefore, the gas purification apparatus 200 can increase the amount of combustion gas (hydrogen, carbon monoxide) contained in the gasified gas after purification by omitting the oxidation reforming furnace.

[Modification example]
The gas refining apparatus 200 may further include a regenerating unit that regenerates the second cleaning liquid used in the oil scrubber 230. FIG. 4 is a diagram illustrating an oil circulation unit 310 and a regeneration unit 350 according to a modified example. In FIG. 4, the broken line arrow indicates the flow of gas (gasification gas, canned gas, and distillate gas). Further, in FIG. 4, the solid arrow indicates the flow of the liquid (condensed water, second cleaning liquid, drained oil, canned liquid, and distillate).

As shown in FIG. 4, the oil circulation unit 310 includes a sedimentation separation unit 320, pipes 322, 330, 334, 336, a pump 332, a heat exchanger 340, and a cooling unit 298. The components substantially the same as the oil circulation unit 290 are designated by the same reference numerals and the description thereof will be omitted.

The sedimentation separation unit 320 separates the drained oil and the condensed water generated in the oil scrubber 230. The settling separation section 320 includes a storage tank 320a and a partition plate 320b. The storage tank 320a stores the drained oil and condensed water generated in the oil scrubber 230. The partition plate 320b divides the inside of the storage tank 320a into a first chamber and a second chamber. The upper part of the partition plate 320b is separated from the upper part of the storage tank 320a. The side portions and the lower portion of the partition plate 320b are connected to the inner wall of the storage tank 320a.

The pipe 234 connects the bottom of the main body 230a of the oil scrubber 230 and the first chamber of the storage tank 320a. Therefore, the drained oil and the condensed water generated in the oil scrubber 230 are stored in the first chamber of the storage tank 320a. In the first chamber of the containment tank 320a, the condensed water settles and is separated from the drainage oil. The settled and separated condensed water is introduced into the tar decanter 260 through the pipe 322. The pipe 322 connects the bottom of the first chamber of the storage tank 320a with the tar decanter 260.

On the other hand, the drainage oil separated by the sedimentation of the condensed water in the first chamber overflows the partition plate 320b and moves to the second chamber of the storage tank 320a. Then, the drainage oil is introduced to the suction side of the pump 332 through the pipe 330. The discharge side of the pump 332 is connected to the pipe 334. The pipe 334 connects the discharge side of the pump 332 and the regeneration unit 350 (regeneration tower 352). The pump 332 introduces the drainage oil separated by the sedimentation separation unit 320 into the regeneration unit 350. The regeneration unit 350 regenerates the drained oil. That is, the recycling unit 350 removes the light tar from the drained oil. The specific configuration of the reproduction unit 350 will be described in detail later.

The drainage oil (second cleaning liquid) regenerated by the regenerating unit 350 is supplied to the dispersion unit 230b of the oil scrubber 230 through the pipe 336.

The heat exchanger 340 exchanges heat between the drainage oil passing through the pipe 334 and the second cleaning liquid passing through the pipe 336. The heat exchanger 340 heats the exhaust oil and cools the second cleaning liquid. The cooling unit 298 is provided between the installation position of the heat exchanger 340 in the pipe 336 and the oil scrubber 230.

The regeneration unit 350 (distillation unit) includes a regeneration tower 352, a reboiler 354, and a capacitor 356. The regeneration tower 352 has a tubular shape. A filling layer is provided in the regeneration tower 352. The packed bed includes shelves. The pipe 334 is connected to the center of the regeneration tower 352. The reboiler 354 draws out the canned liquid from the bottom of the regeneration tower 352 and heats it to a predetermined temperature. The canned gas heated by the reboiler 354 and vaporized from the canned liquid is returned to the regeneration tower 352. On the other hand, the canned liquid from which the canned gas has been removed by the reboiler 354 is introduced into the pipe 336 as the second cleaning liquid. The condenser 356 extracts the distillate gas from the top of the regeneration tower 352, cools it to a predetermined temperature, and condenses it. A part of the distillate condensed by the condenser 356 is extracted to the outside, and the rest is returned to the regeneration tower 352. The distillate contains light tar.

The oil scrubber 230 removes the light tar from the gasification gas by dissolving the light tar contained in the gasification gas in the second cleaning liquid. Therefore, in the oil scrubber 230, as the operation time becomes longer, the accumulated amount of light tar in the second cleaning liquid increases, and the second cleaning liquid deteriorates. Therefore, the modified example includes a reproduction unit 350. As a result, the light tar can be removed from the drained oil and reused in the oil scrubber 230. Therefore, in the modified example, the frequency of replacement of the second cleaning liquid can be further reduced.

Although the embodiments have been described above with reference to the attached drawings, it goes without saying that the present disclosure is not limited to the above embodiments. It is clear to those skilled in the art that various modifications or modifications can be conceived within the scope of the claims, and it is understood that they also naturally belong to the technical scope of the present disclosure. Will be done.

For example, in the above-described embodiment, the case where the gas purification device 200 purifies the gasified gas produced by the gasification furnace 150 has been given as an example. However, the gas purification apparatus 200 can purify a gas containing solid particles and an organic compound such as tar or olefin. The gas refining apparatus 200 may purify the gas produced by an apparatus for steaming (dry distillation) raw materials such as a lime kiln and a coke oven. Further, the gas refining device 200 may purify the exhaust gas of the painting factory.

Further, in the above embodiment, the gasification furnace 150 has been described by taking as an example a configuration in which a solid raw material is gasified in a fluidized bed of a fluidized medium. However, the gasification furnace 150 only needs to be able to gasify the solid raw material with the heat of the flow medium. The gasification furnace 150 may gasify the solid raw material in the moving layer of the flow medium, for example.

Further, in the above embodiment, the configuration in which the gas refining apparatus 200 includes a water supply unit for supplying the wastewater generated in the oil scrubber 230 to the water scrubber 220 is given as an example. However, the gas purification apparatus 200 does not have to supply the wastewater generated by the oil scrubber 230 to the water scrubber 220.

Further, in the above embodiment, the configuration in which the gas refining apparatus 200 is provided with the tar decanter 260 is given as an example. However, the gas refining apparatus 200 does not have to include the tar decanter 260.

Further, in the above embodiment, the configuration in which the gas purification device 200 includes the attraction fan 250 is given as an example. However, the attraction fan 250 is not an essential configuration. For example, if the gas can pass through the dust removing unit 210, the water scrubber 220, and the oil scrubber 230 in this order due to the pressure difference, the attraction fan 250 can be omitted.

Further, an acid may be added to the first cleaning liquid sprayed by the water scrubber 220 to make the first cleaning liquid acidic. As a result, the water scrubber 220 can efficiently remove the alkaline component (for example, ammonia) contained in the gas. Similarly, alkali may be added to the first cleaning liquid sprayed by the water scrubber 220 to make the first cleaning liquid alkaline. As a result, the water scrubber 220 can efficiently remove the acid component (for example, sulfur oxide) contained in the gas.

Further, the water circulation unit 280 may include a mechanism for extracting drainage and a mechanism for replenishing the first cleaning liquid. Similarly, the oil circulation unit 290 may include a mechanism for draining the drained oil and a mechanism for replenishing the second cleaning liquid.

Further, in the above embodiment, the gas refining apparatus 200 may include a sedimentation separation unit 320 for separating the drained oil and the condensed water generated in the oil scrubber 230.

Further, in the above embodiment, the configuration in which the dispersion portion 230b sprays the second cleaning liquid into the main body 230a is given as an example. However, the structure of the dispersion portion 230b is not limited as long as the second cleaning liquid can be dispersed substantially uniformly with respect to the horizontal cross section of the main body 230a. The dispersion portion 230b may include, for example, a dispersion material.

Further, in the above embodiment and the modified example, the pump may be provided in the pipe 234. Further, in the modified example, a pump may be provided in the pipe 336 and the condenser 356.

Further, in the above embodiment, the case where the first cleaning liquid contains at least water is given as an example. However, the composition of the first cleaning liquid is not limited as long as it is lower than the melting point of the removing substance contained in the gas. The first cleaning solution is, for example, either one or both of methanol and ethanol. The gas purification apparatus 200 can efficiently remove the removed substance by bringing the first cleaning liquid having a temperature lower than the melting point of the removed substance into contact with the gasified gas.

In the above embodiment, tar containing an aromatic compound was given as an example as a removing substance. However, the removal material may include olefins.

Further, the flow rate of the first cleaning liquid supplied by the water scrubber 220 may be determined according to the temperature or flow rate of the gasified gas exhausted from the bag filter 140. For example, the water scrubber 220 is provided with a temperature measuring unit for measuring the temperature of the gasified gas exhausted from the bag filter 140 or the temperature inside the water scrubber 220, and the control unit is based on the measurement result of the temperature measuring unit. The flow rate of the first cleaning liquid to be supplied is determined. In this case, the control unit may determine the flow rate of the first cleaning liquid supplied by the water scrubber 220 so that the temperature inside the water scrubber 220 is lower than the melting point of the heavy tar and equal to or higher than the melting point of the light tar. As a result, the control unit can set the temperature of the gas at the outlet of the water scrubber 220 to be lower than the melting point of the heavy tar, and can improve the removal rate of the heavy tar.

Further, in the above embodiment, the configuration in which the water scrubber 220 includes the spray portion 220b is given as an example. However, the structure of the water scrubber 220 is not limited as long as the gasified gas from which the solid particles have been removed by the dust removing unit 210 can be brought into contact with the first cleaning liquid. The water scrubber 220 may have the same configuration as the oil scrubber 230, and may include, for example, a dispersant.

This disclosure can be used for gas refining methods and gas refining equipment.

200: Gas refiner 210: Dust removal unit 220: Water scrubber (first scrubber) 230: Oil scrubber (second scrubber) 234: Piping (water supply unit) 260: Tar decanter (water supply unit) 280: Water circulation unit (water) Supply department)

Claims (8)

1. The process of removing solid particles contained in the gas and
   A step of bringing the gas from which the solid particles have been removed into contact with a first cleaning liquid having a temperature lower than the melting point of the removing substance contained in the gas.
   After performing the step of bringing the first cleaning liquid into contact, the step of bringing the gas in contact with the first cleaning liquid into contact with the second cleaning liquid having a higher affinity for the removing substance than the first cleaning liquid.
   Gas purification method including.
2. The gas purification method according to claim 1, wherein the flow rate of the first cleaning liquid is determined according to the temperature of the gas from which the solid particles have been removed after performing the step of removing the solid particles.
3. The first cleaning liquid contains at least water and contains at least water.
   The gas purification method according to claim 1 or 2, wherein the second cleaning liquid contains at least oil.
4. A dust remover that removes solid particles contained in the gas,
   A first scrubber that brings the gas from which the solid particles have been removed by the dust removing portion into contact with a first cleaning liquid having a temperature lower than the melting point of the removing substance contained in the gas.
   A second scrubber that brings the gas treated by the first scrubber into contact with a second cleaning liquid having a higher affinity for the removing substance than the first cleaning liquid.
   A gas purification device equipped with.
5. The first cleaning liquid contains at least water and contains at least water.
   The gas refining apparatus according to claim 4, wherein the second cleaning liquid contains at least oil.
6. The gas purification apparatus according to claim 5, further comprising a water supply unit that supplies the wastewater generated by the second scrubber to the first scrubber.
7. The gas purification apparatus according to claim 5 or 6, further comprising a tar decanter for storing the wastewater generated in the first scrubber and the wastewater generated in the second scrubber.
8. The gas purification apparatus according to any one of claims 4 to 7, further comprising equipment for utilizing the removed substance removed from the gas in the first scrubber.

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