CN114746165A

CN114746165A - Gas purification method and gas purification device

Info

Publication number: CN114746165A
Application number: CN202080082836.4A
Authority: CN
Inventors: 安居晃树
Original assignee: IHI Corp
Current assignee: IHI Corp
Priority date: 2019-12-02
Filing date: 2020-07-17
Publication date: 2022-07-12
Also published as: JPWO2021111671A1; JP7351349B2; WO2021111671A1

Abstract

The gas purification method includes a step of removing solid particles contained in a gas (dust removal step S110), a step of bringing the gas from which the solid particles are removed into contact with a first cleaning liquid having a temperature lower than the melting point of a removing substance contained in the gas (water cleaning step S120), and a step of bringing the gas brought into contact with the first cleaning liquid into contact with a second cleaning liquid having a higher affinity for the removing substance than the first cleaning liquid after the step of bringing the gas into contact with the first cleaning liquid (oil cleaning step S130).

Description

Gas purification method and gas purification apparatus

Technical Field

The present disclosure relates to a gas purification method and a gas purification apparatus. The application is based on and claims priority from japanese patent application No. 2019-217726, 12/2/2019, the contents of which are incorporated herein by reference.

Background

As a gas purification technique, an exhaust gas treatment facility having a bag filter and an oil scrubber is disclosed (for example, patent document 1). In the technique of patent document 1, a bag filter removes dust from a gas. The oil scrubber contacts the gas from which dust is removed by the bag filter with a cleaning oil to remove organic compounds in the gas. The oil scrubber has a gas-liquid contact portion that contacts the cleaning oil with the gas. The cleaning oil after contact with the gas is supplied again to the gas-liquid contact portion to circulate in the oil scrubber.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2006-21187

Disclosure of Invention

Problems to be solved by the invention

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

In this case, circulation of the cleaning oil in the oil washer becomes difficult, and the oil washer cannot be operated. Therefore, there is a problem that the cleaning oil needs to be frequently replaced with new oil, resulting in an increase in cost. Therefore, it is desired to develop a technique capable of purifying a gas at low cost.

The present disclosure has been made in view of the above problems, and an object thereof is to provide a gas purification method and a gas purification apparatus capable of purifying a gas at low cost.

Means for solving the problems

In order to solve the above problem, a gas purification method according to an embodiment of the present disclosure includes a step of removing solid particles contained in a gas, a step of contacting the gas from which the solid particles are removed with a first cleaning liquid at a temperature lower than a melting point of a removal substance contained in the gas, and a step of contacting the gas after contacting with the first cleaning liquid with a second cleaning liquid having a higher affinity for the removal substance than the first cleaning liquid after the step of contacting with the first cleaning liquid is performed.

The flow rate of the first cleaning liquid may be determined based on the temperature of the solid particle removed gas after the solid particle removing step is performed.

Further optionally, the first cleaning fluid comprises at least water and the second cleaning fluid comprises at least oil.

In order to solve the above problem, a gas purification apparatus according to an embodiment of the present disclosure includes a dust removing unit that removes solid particles contained in a gas, a first scrubber that brings the gas from which the solid particles are removed by the dust removing unit into contact with a first cleaning liquid at a temperature lower than a melting point of a removal substance contained in the gas, and a second scrubber that brings a gas treated by the first scrubber into contact with a second cleaning liquid, wherein the second cleaning liquid has a higher affinity for the removal substance than the first cleaning liquid.

The gas refining apparatus may further include a water supply unit for supplying the drain water produced by the second scrubber to the first scrubber.

The gas refining apparatus may further include a tar settling tank for storing the wastewater produced by the first scrubber and the wastewater produced by the second scrubber.

The gas purification apparatus may further include a device for utilizing the removal material removed from the gas in the first scrubber.

Effects of the invention

According to the present disclosure, the gas can be purified at low cost.

Drawings

Fig. 1 is a diagram for explaining a device for producing a gasified gas.

Fig. 2 is a diagram illustrating a gas purification apparatus.

Fig. 3 is a flowchart illustrating a process flow of the gas purification method.

Fig. 4 is a diagram illustrating an oil circulation unit and a regeneration unit in a modification.

Detailed Description

Embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. Dimensions, materials, other specific numerical values and the like shown in the embodiments are merely examples for easy understanding, and the present disclosure is not limited thereto unless particularly stated. In the present specification and the drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and overlapping description thereof is omitted, and elements not directly related to the present disclosure are omitted from illustration.

[ gasified gas production apparatus 100]

Fig. 1 is a diagram for explaining a gasified gas production apparatus 100. In fig. 1, solid arrows indicate flows of a solid material (a fluid medium, a raw material, and a residue) and a liquid (water). In fig. 1, arrows of broken lines indicate flows of gases (water vapor, gasified gas, air, and combustion exhaust gas).

As shown in fig. 1, the gasified 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, a heat exchanger 170, and a gas purification apparatus 200.

The gasified gas production apparatus 100 gasifies the raw material using the fluidized bed of the fluidized medium to produce a gasified gas (synthesis gas). The raw material is, for example, a solid raw material such as coal (brown coal or the like) or biomass (wood chip particles or the like). The gasified gas production apparatus 100 is a circulation flow layer type gasification system. That is, the gasified gas production apparatus 100 circulates the fluid medium as the 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 furnace 110 is cylindrical. The combustion furnace 110 is supplied with fuel and a fluid medium from a gasification furnace 150, which will be described later, through a pipe 112. The pipe 112 connects the lower portion of the combustion furnace 110 and the gasification furnace 150. The combustion furnace 110 burns the fuel to heat the fluid medium to 600 ℃ to 1000 ℃. 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 burner 110 and the cyclone 120.

The cyclone 120 performs solid-gas separation of a mixture of the combustion exhaust gas and the fluid medium introduced from the combustion furnace 110 through the pipe 114. The high-temperature fluidizing medium separated by the cyclone 120 is introduced into the gasification furnace 150 through the pipe 122. The pipe 122 connects the bottom of the cyclone 120 and the gasification furnace 150.

The high-temperature fluidizing medium is fluidized by a fluidizing gas (e.g., steam) in the gasification furnace 150. Specifically, the gasification furnace 150 includes a housing tank 152 and a steam introduction part 154. The holding tank 152 holds the flowing medium as well as the raw material.

The steam introduction part 154 introduces steam into the accommodation groove 152. The steam introduction part 154 includes a wind box 154a and a boiler 154 b. The bellows 154a is disposed below the accommodation groove 152. The upper portion of the bellows 154a also serves as the bottom surface of the accommodation groove 152. The upper part of the bellows 154a is constituted by a dispersion plate which can be ventilated. The boiler 154b generates water vapor. Boiler 154b is connected to windbox 154 a. Steam generated by the boiler 154b is introduced into the windbox 154 a. The steam introduced into the bellows 154a is introduced into the accommodation groove 152 from the bottom surface (dispersion plate) of the accommodation groove 152. The boiler 154b introduces water vapor into the windbox 154a at a flow rate that can form a fluidized bed of the fluidizing agent in the accommodation tank 152. Therefore, the high-temperature fluidizing medium introduced from the cyclone 120 is fluidized by the steam. Thereby, a fluidized layer of the fluidizing agent (for example, a bubble fluidized layer (bubbling fluidized layer)) is formed in the housing groove 152.

Further, the raw material is introduced into the gasification furnace 150 (the holding tank 152) through the pipe 122. The introduced raw material is gasified by heat of 600 ℃ to 900 ℃ of the flowing medium, thereby producing a gasified gas (synthesis gas). The gasified gas produced by the gasification furnace 150 is introduced into the cyclone 160 through the pipe 156. The pipe 156 connects the upper part of the gasification furnace 150 and the cyclone 160.

The cyclone 160 performs solid-gas separation on the gasified gas discharged from the gasification furnace 150. The gasified gas subjected to the solid-gas separation is introduced into the heat exchanger 170 through the pipe 162. The pipe 162 connects the upper portion of the cyclone 160 and the heat exchanger 170. The solid matter (the fluid medium, the residue of the raw material, and a part of tar) obtained by the solid-gas separation 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 the present embodiment, the raw material is also introduced into the pipe 164.

The heat exchanger 170 exchanges heat between the gasified gas from which the solid gas is separated by the cyclone 160 and steam, high-pressure water, or the like. The heat exchanger 170 recovers sensible heat of the gasified gas by the steam so that the output temperature of the gasified gas is 150 ℃ to 200 ℃. The gasified gas cooled by the heat exchanger 170 is introduced into a gas purification apparatus 200, which will be described later, through a 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 apparatus 200 (dust removal unit 210).

As described above, the fluidized medium fluidized 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. Thus, according to the gasified gas production apparatus 100 of the present embodiment, the fluidized medium circulates by being introduced into the combustion furnace 110 again while moving in the order of the combustion furnace 110, the cyclone 120, and the gasification furnace 150.

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

The combustion exhaust gas separated by the cyclone 120 is introduced into the heat exchanger 130 through the pipe 124. A 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 bag filter 140 removes dust from the combustion exhaust gas introduced from the heat exchanger 130 through the pipe 132. The pipe 132 connects the heat exchanger 130 and the bag filter 140. The flue gas from which dust is removed by the bag filter 140 is denitrated by a denitrator not shown. The denitrated combustion exhaust gas is desulfurized by a desulfurization device, not shown. The desulfurized combustion exhaust gas is discharged to the outside. Note that the denitration device and the desulfurization device may be omitted.

As described above, the gasification furnace 150 gasifies the raw material at a low temperature range of 600 ℃ to 900 ℃. Therefore, the gasified gas generated by the gasification furnace 150 contains tar. Although a part of the tar contained in the gasified gas is separated by the cyclone 160, most of the tar is introduced into the heat exchanger 170 together with the gasified gas. The gasified gas also contains ash derived from the raw material and solid particles (dust) such as a fluid medium.

For this purpose, the gasified gas production apparatus 100 includes a gas purification apparatus 200. The gas purification apparatus 200 removes impurities (tar and solid particles) from the gasified gas, thereby purifying the gasified gas. The gas purification apparatus 200 will be described in detail below.

[ gas refining apparatus 200]

Fig. 2 is a diagram illustrating a gas purification apparatus 200. In fig. 2, arrows of broken lines indicate the flow of the gasified gas. In fig. 2, solid arrows indicate flows of liquids (the first cleaning liquid, the drain, the second cleaning liquid, and the drain).

As shown in fig. 2, the gas purifying apparatus 200 includes a dust removing unit 210, a water scrubber 220, an oil scrubber 230, an oil mist separator 240, a guide fan 250, a tar settling tank 260, a tar distributing device 270, a water circulating unit 280, and an oil circulating unit 290. The dust removing unit 210, the water scrubber 220, the oil scrubber 230, and the oil mist separator 240 communicate with each other. Further, the oil mist separator 240 is connected to a suction side of the guide fan 250. Therefore, when the guide fan 250 is driven, the gasified gas passes through the dust removing unit 210, the water scrubber 220, the oil scrubber 230, and the oil mist separator 240 in this order.

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

The gasified gas from which the solid particles and a part of the 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 are removed by the dust removing unit 210 into contact with the first cleaning liquid. The first cleaning liquid has a lower melting point than the heavy tar (removed matter) 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 ℃ or higher and less than 100 ℃ (for example, about 85 ℃) 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 spray unit 220 b. The body 220a is cylindrical. The upper portion of the main body 220a is connected to a pipe 222. The piping 222 connects the water scrubber 220 and the oil scrubber 230. A pipe 282 is connected to the bottom of the main body 220 a. The pipe 282 connects the water scrubber 220 and the tar settling tank 260. The pipe 212 is connected between the connection position of the pipe 222 and the connection position of the pipe 282 in the main body 220 a. Therefore, the gasified gas introduced from the pipe 212 rises in the main body 220a and is exhausted from the pipe 222.

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

Therefore, the gasified gas contacts the first cleaning liquid while passing through (rising) the main body 220a, and is cooled to about 85 ℃. Thereby, the heavy tar remaining in the gasified gas is condensed and removed from the gasified 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 settling tank 260 through the pipe 282.

In this way, the water scrubber 220 can condense the heavy tar while maintaining fluidity by cooling the gasified gas to 80 ℃ or higher and less than 100 ℃. Thus, the water scrubber 220 can move the heavy tar to the tar settling tank 260 by its own weight together with the first cleaning liquid. That is, the water scrubber 220 can easily move heavy tar to the tar settling tank 260.

In addition, the water scrubber 220 maintains the gasification gas above 80 ℃. Thus, the water scrubber 220 can avoid the problem of naphthalene precipitation on the inner wall of the main body 220 a.

In addition, ammonia and sulfur oxides (SOx) are dissolved in the first cleaning liquid. Thus, in the case where ammonia or sulfur oxides are contained in the gasified gas, the water scrubber 220 can also remove ammonia and sulfur oxides from the gasified gas.

The oil scrubber 230 (second scrubber) contacts the gasified gas treated by the water scrubber 220 with a second cleaning liquid. The second cleaning liquid has a higher affinity for tar (removal substance) than the first cleaning liquid. The second cleaning liquid is a liquid containing at least oil. The oil includes, for example, any one or more of mineral oil, light oil, biodiesel fuel, and vegetable oil. The oil scrubber 230 causes the light tar contained in the gasified gas to be dissolved in the second cleaning liquid by bringing the gasified gas into contact with the second cleaning liquid. Thereby, 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 230 c. The body 230a has a cylindrical shape. A pipe 232 is connected to an upper portion of the main body 230 a. The pipe 232 connects the oil scrubber 230 and the oil mist separator 240. A pipe 234 is connected to the bottom of the body 230 a. The pipe 234 connects the oil scrubber 230 and the tar settling tank 260. A pipe 292 is provided between the connection position of the pipe 232 and the connection position of the pipe 234 in the main body 230 a. The pipe 292 connects the oil scrubber 230 and the pump 294. The pipe 222 is connected between the connection position of the pipe 232 and the connection position of the pipe 292 in the main body 230 a. Therefore, the gasified gas introduced from the pipe 222 rises in the main body 230a and is exhausted from the pipe 232.

The dispersing unit 230b is provided between the connection position of the pipe 232 and the connection position of the pipe 222 in the main body 230 a. The dispersing unit 230b sprays the second cleaning liquid having a temperature (for example, 50 ℃ or lower) at which the water vapor contained in the gasified gas is condensed into the main body 230 a.

Therefore, the gasified gas contacts the second cleaning liquid during the passage (rising) through the body 230 a. Thereby, the light tar contained in the gasified gas is dissolved in the second cleaning liquid. The light tar dissolved in the second cleaning liquid falls to the bottom of the main body 230 a.

In addition, the gasified gas is cooled by the second cleaning liquid. Thereby, water vapor remaining in the gasified gas is condensed and removed from the gasified gas. And, the condensed water vapor, i.e., condensed water, falls to the bottom of the body 230 a. The condensed water has a higher mass density than the drain oil containing the second cleaning liquid and the light tar. Therefore, the condensed water is retained below the oil drain layer at the bottom of the body 230 a. That is, in the body 230a, the drain oil is separated from the condensed water by settling.

The condensed water (drain water) remaining at the bottom of the main body 230a is introduced into the tar settling tank 260 through the pipe 234. The drain oil that has accumulated above the condensed water in the main body 230a is sucked into the pump 294 through the pipe 292.

The gasified gas from which the light tar and the water vapor are removed is introduced into the oil mist separator 240 through the pipe 232.

The filling layer 230c is provided between the connection position of the pipe 222 and the dispersing part 230b in the main body 230 a. The packing layer 230c has rings, wire nets, shelves, trays, etc. The filling layer 230c reduces the descending speed of the second cleaning liquid. The oil scrubber 230 includes the filling layer 230c, and thus the contact efficiency between the gasified 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 oil mist separator 240 removes oil mist (second cleaning liquid) contained in the gasified gas. A pipe 242 is connected to an upper portion of the oil mist separator 240. The pipe 242 connects the oil mist separator 240 and the suction side of the guide fan 250. A pipe 244 is connected to the bottom of the oil mist separator 240. The pipe 244 connects the oil mist separator 240 and the oil scrubber 230 (main body 230 a). In the present embodiment, the pipe 242 is connected below the filler layer 230c of the main body 230 a. The pipe 232 is connected between a connection position of the pipe 242 and a connection position of the pipe 244 in the oil mist separator 240. Therefore, the gasified gas introduced from the pipe 232 is discharged from the pipe 242 after the oil mist is removed in the oil mist separator 240. The oil mist removed from the gasified gas in the oil mist separator 240 is returned to the oil scrubber 230 through the pipe 244.

The guide fan 250 is connected to a pipe 242 (oil mist separator 240) on the suction side and a pipe 252 on the air outlet side. The guide fan 250 sucks the gasified gas (refined gasified gas) from which the oil mist is removed by the oil mist separator 240, and conveys the sucked gas to the subsequent gasified gas utilization facility through the pipe 252. The gasified gas utilization equipment is power generation equipment such as a gas engine or a chemical production device.

The tar settling tank 260 stores the drain water generated in the water scrubber 220 and the condensed water generated in the oil scrubber 230. The tar settling tank 260 separates the drainage into supernatant and sediment based on the difference in mass density and particle size. The sediment contains heavy tar.

The tar distribution device 270 is constituted by, for example, a screw conveyor. The tar distribution device 270 sends out the sediment (heavy tar) separated from the tar settling tank 260 to the outside. The heavy tar (removed matter) can be used as fuel for combustion equipment (equipment) such as boilers, generators, etc., or for repelling beasts.

The water circulation part 280 circulates the first cleaning liquid in the water scrubber 220. The water circulation unit 280 includes

pipes

282, 284, and 288, and a pump 286. The pipe 284 connects the tar settling tank 260 and the suction side of the pump 286. The pipe 288 connects the outlet side of the pump 286 and the spraying section 220 b. The pump 286 supplies the supernatant liquid separated in the tar settling tank 260 to the spraying section 220b as the first cleaning liquid.

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

The oil circulation part 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 outlet side of the pump 294 to the dispersing section 230b of the oil scrubber 230. The pump 294 supplies the drain oil staying in the body 230a of the oil scrubber 230 to the dispersion part 230b as the second cleaning liquid. The cooling section 298 is provided in the pipe 296. The cooling section 298 cools the second cleaning liquid. With the structure having the cooling portion 298, the oil scrubber 230 can efficiently dissolve the light tar contained in the gasified gas in the second cleaning liquid.

[ gas refining method ]

Next, a gas purification method using the gas purification apparatus 200 will be described. Fig. 3 is a flowchart for explaining a process flow of the gas purification method. As shown in fig. 3, the gas purification method includes a dust removal process S110, a water cleaning process S120, and an oil cleaning process 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 washing Process S120]

The water washing step S120 is a step of bringing the first cleaning liquid into contact with the gas generated by the water scrubber 220 and from which the solid particles have been removed in the dust removal step S110. By performing the water washing step S120, heavy tar is removed from the gasified gas.

[ oil cleaning Process S130]

The oil washing step S130 is a step in which the oil washer 230 brings the gasified gas from which the heavy tar has been removed in the water washing step S120 into contact with the second cleaning liquid. By performing the oil cleaning step S130, the light tar is removed from the gasified gas.

As described above, the gas purification apparatus 200 and the gas purification method using the same according to the present embodiment include the dust removing unit 210. This can reduce the processing load on the water scrubber 220. Therefore, the gas purification apparatus 200 can downsize the water scrubber 220 and the tar settling tank 260.

The gas refining apparatus 200 includes a water scrubber 220 and an oil scrubber 230. In the prior art in which the gasified gas is refined only by the water scrubber 220, the removal rate of tar is about 10% to 25%, which is low. On the other hand, the gas refining apparatus 200 can remove heavy tar by the water scrubber 220 and light tar by the oil scrubber 230. Therefore, the gas purification apparatus 200 can effectively remove tar contained in the gasified gas.

In the conventional technique of purifying the gasified gas only by the oil scrubber 230, not only the light tar but also the heavy tar are dissolved in the second cleaning liquid. The heavy tar has a high melting point, and when dissolved in the second cleaning liquid, the viscosity of the second cleaning liquid increases. In this way, circulation of the second cleaning liquid in the oil scrubber 230 becomes difficult, and operation of the oil scrubber 230 becomes impossible. Therefore, in the related art in which the gasified gas is refined only by the oil scrubber 230, the second cleaning liquid must be frequently replaced.

In contrast, the gas refining apparatus 200 has a water scrubber 220 upstream of the oil scrubber 230. Thereby, the oil scrubber 230 brings the gasified gas from which the heavy tar is removed into contact with the second cleaning liquid. Even if the light tar is dissolved in the second cleaning liquid, the viscosity of the light tar does not increase as compared with the heavy tar. Therefore, the oil circulation part 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, compared to the prior art having only the oil scrubber 230. Thus, the gas purification apparatus 200 can purify the gasified gas at low cost.

In addition, the related art in which the gasified gas is refined only by the oil scrubber 230 cannot remove water-soluble impurities. Therefore, the related art refining the gasified gas only by the oil scrubber 230 has a risk of causing a failure in a subsequent gasified gas utilization apparatus utilizing the gasified gas due to water-soluble impurities. On the other hand, since the gas purification 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 gasified gas. Therefore, the gas purification apparatus 200 can prevent the occurrence of a failure in a subsequent gasified gas utilization facility that utilizes the gasified gas.

The gas purification apparatus 200 further includes a tar settling tank 260. Thereby, the gas purification apparatus 200 can separate heavy tar from the drainage. Therefore, the gas purification apparatus 200 can effectively use the heavy tar.

The gas purification apparatus 200 further includes a water supply unit (the pipe 234, the tar settling tank 260, and the water circulation unit 280). Thus, in the gas purification apparatus 200, the drain water generated in the oil scrubber 230 can be used for the water scrubber 220. Therefore, the gas purification apparatus 200 can reduce the cost required for the first cleaning liquid.

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

[ modified examples ]

The gas purification apparatus 200 may further include a regeneration unit for regenerating the second cleaning liquid used in the oil scrubber 230. Fig. 4 is a diagram illustrating the oil circulation unit 310 and the regeneration unit 350 in the modification. In fig. 4, arrows of broken lines indicate flows of gases (a gasified gas, a tank output gas, and a distillate gas). In addition, solid arrows in fig. 4 indicate the flows of the liquids (the condensed water, the second cleaning liquid, the drain oil, the tank output liquid, and the distillate).

As shown in fig. 4, the oil circulation unit 310 includes a settling separation unit 320,

pipes

322, 330, 334, and 336, a pump 332, a heat exchanger 340, and a cooling unit 298. Substantially the same components as those of the oil circulation unit 290 are denoted by the same reference numerals, and description thereof is omitted.

The settling separator 320 separates oil drain and condensed water generated in the oil scrubber 230. The settling separator 320 has a housing tank 320a and a partition 320 b. The receiving tank 320a stores drain oil and condensed water generated from the oil scrubber 230. The partition 320b divides the interior of the housing groove 320a into a first chamber and a second chamber. The upper portion of the partition 320b is spaced apart from the upper portion of the receiving groove 320 a. The side portion of the partition 320b and the lower portion are coupled to the inner wall of the receiving groove 320 a.

The piping 234 connects the bottom of the body 230a of the oil scrubber 230 and the first chamber of the housing tank 320 a. Thus, the drain oil and the condensed water generated from the oil scrubber 230 are stored in the first chamber of the housing tank 320 a. In the first chamber of the receiving groove 320a, the condensed water is settled and separated from the discharged oil. The condensed water separated by settling is introduced into the tar settling tank 260 through the pipe 322. The pipe 322 connects the bottom of the first chamber of the housing tank 320a and the tar settling tank 260.

On the other hand, in the first chamber, the drain oil separated by the settling of the condensed water moves to the second chamber of the housing tank 320a over the partition plate 320 b. The drain oil is introduced into the suction side of the pump 332 through the pipe 330. The outlet side of the pump 332 is connected to a pipe 334. The outlet side of the pump 332 is connected to the regeneration unit 350 (regeneration tower 352) by a pipe 334. The pump 332 introduces the drain oil separated in the settling separation section 320 into the regeneration section 350. The regeneration unit 350 regenerates the drain oil. That is, the regeneration section 350 removes light tar from the oil discharge. The specific configuration of the regeneration unit 350 will be described in detail later.

The drain oil (second cleaning liquid) regenerated by the regeneration 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 drain oil passing through the pipe 334 and the second cleaning liquid passing through the pipe 336. The heat exchanger 340 heats the drain oil and cools the second cleaning liquid. The cooling portion 298 is provided between the installation position of the heat exchanger 340 and the oil scrubber 230 in the pipe 336.

The regeneration section 350 (distillation section) includes a regeneration column 352, a reboiler 354, and a condenser 356. The regeneration tower 352 has a cylindrical shape. A packed bed is provided in the regeneration column 352. The filling layer has shelves. The pipe 334 is connected to the center of the regeneration tower 352. Reboiler 354 draws the drum output from the bottom of regenerator 352 and heats it to a predetermined temperature. The drum output gas vaporized from the drum output liquid is returned to the regeneration tower 352 by being heated by the reboiler 354. On the other hand, the tank outlet liquid from which the tank outlet gas has been removed by the reboiler 354 is introduced into the pipe 336 as the second cleaning liquid. The condenser 356 extracts an distillate gas from the top of the regeneration tower 352, and cools the distillate gas to a predetermined temperature to condense the distillate gas. The distillate concentrated by the condenser 356 is partially extracted to the outside, and the remainder is sent back to the regeneration column 352. The distillate contained light tar.

The oil scrubber 230 removes light tar contained in the gasified gas by dissolving the light tar in the second cleaning liquid. Therefore, in the oil scrubber 230, the accumulation amount of the light tar in the second cleaning liquid increases with the increase of the operation time, and the second cleaning liquid deteriorates. For this reason, the modification includes a regeneration unit 350. Thereby, light tar can be removed from the drain oil and reused in the oil scrubber 230. Thus, the modification can further reduce the frequency of exchanging the second cleaning liquid.

The embodiments have been described above with reference to the drawings, but it is needless to say that the present disclosure is not limited to the above embodiments. It is to be understood that various changes and modifications obvious to those skilled in the art may be made within the scope of the claims and the technical scope of the present disclosure.

For example, in the above embodiment, the gas purification apparatus 200 is exemplified to purify the gas produced by the gasification furnace 150. However, the gas purification apparatus 200 can purify a gas containing organic compounds such as solid particles, tar, and olefins. The gas purification apparatus 200 can also purify a gas produced by an apparatus for steaming (dry distillation) a material such as a lime kiln or a coke oven (manufactured by sintering し, manufactured by sintering き). The gas purification apparatus 200 can purify exhaust gas from a coating plant.

In the above embodiment, an example in which the gasification furnace 150 is configured to turn a solid material into a gas through a fluidized bed of a fluidizing agent has been described. However, the gasification furnace 150 may gasify the solid raw material by heat of the fluid medium. The gasification furnace 150 can gasify the solid raw material through a moving bed of the fluidized medium, for example.

In the above embodiment, the gas purification apparatus 200 is configured to have a water supply unit for supplying the drain water generated in the oil scrubber 230 to the water scrubber 220. However, the gas refining apparatus 200 may not supply the drain water generated by the oil scrubber 230 to the water scrubber 220.

In the above embodiment, the gas purification apparatus 200 is configured to have the tar settling tank 260. However, the gas purification apparatus 200 may not have the tar settling tank 260.

In the above embodiment, the gas purification apparatus 200 is configured to have the guide fan 250. However, the guide fan 250 is not necessarily configured. For example, the guide fan 250 may be omitted as long as the gas can be sequentially passed through the dust removing part 210, the water scrubber 220, and the oil scrubber 230 by the pressure difference.

In addition, an acid may be added to the first cleaning liquid sprayed to the water scrubber 220 so that the first cleaning liquid is acidic. Thereby, the water scrubber 220 can effectively remove alkaline components (e.g., ammonia gas) contained in the gas. Likewise, an alkali may be added to the first cleaning liquid sprayed to the water scrubber 220 so that the first cleaning liquid is alkaline. Thus, the water scrubber 220 can effectively remove acid components (e.g., sulfur oxides) contained in the gas.

The water circulation unit 280 may further include a mechanism for extracting the drain water and a mechanism for replenishing the first cleaning liquid. Similarly, the oil circulation unit 290 may further include a mechanism for extracting oil and a mechanism for replenishing the second cleaning liquid.

In the above embodiment, the gas purification apparatus 200 may further include a settling separation unit 320 for separating the drain oil and the condensed water generated in the oil scrubber 230.

In the above embodiment, the dispersing unit 230b is configured to spray the second cleaning liquid into the main body 230 a. However, the configuration is not limited as long as the dispersing unit 230b can substantially uniformly disperse the second cleaning liquid with respect to the horizontal cross section of the body 230 a. The dispersing unit 230b may contain a dispersing material, for example.

In the above embodiment and modification, a pump may be provided in the pipe 234. In the modification, a pump may be provided in the pipe 336 and the condenser 356.

In the above embodiment, an example is given in which the first cleaning liquid contains at least water. However, the first cleaning liquid is not limited to a specific one as long as it has a lower melting point temperature than the removing substance contained in the gas. The first cleaning liquid may be, for example, either or both of methanol and ethanol. The gas purification apparatus 200 can effectively remove the removal substance by bringing the first cleaning liquid having a temperature lower than the melting point of the removal substance into contact with the gasified gas.

In the above embodiment, the removed substance is exemplified by tar containing an aromatic compound. However, the removal material may also contain olefins.

The flow rate of the first cleaning liquid supplied to the water scrubber 220 may be determined according to the temperature or the flow rate of the gas exhausted from the bag filter 140. For example, a temperature measuring unit that measures the temperature of the gas exhausted from the bag filter 140 or the temperature inside the water scrubber 220 is provided, and the control unit determines the flow rate of the first cleaning liquid supplied to the water scrubber 220 based on the measurement result of the temperature measuring unit. In this case, the control unit determines the flow rate of the first cleaning liquid supplied to the water scrubber 220 so that the temperature in 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. Thus, the control unit can lower the gas temperature at the outlet of the water scrubber 220 to below the melting point of the heavy tar, and can increase the removal rate of the heavy tar.

In the above embodiment, the water scrubber 220 is configured to have the spray unit 220 b. However, the water scrubber 220 is not limited in structure as long as the first cleaning liquid can contact the gasified gas from which the solid particles are removed by the dust removing unit 210. The water scrubber 220 may also be structurally identical to the oil scrubber 230, for example, and may also have a dispersed material.

Industrial applicability of the invention

The present disclosure can be used for a gas purification method and a gas purification apparatus.

Description of the reference numerals

200: gas purification apparatus, 210: dust removal portion, 220: water scrubber (first scrubber), 230: oil scrubber (second scrubber), 234: piping (water supply unit), 260: tar settling tank (water supply section), 280: a water circulation unit (water supply unit).

Claims

1. A gas refining process comprising:

a step of removing solid particles contained in the gas,

a step of bringing the gas from which the solid particles have been removed into contact with a first cleaning liquid, the first cleaning liquid having a temperature lower than a melting point of a removing substance contained in the gas, and

and a step of bringing the gas brought into contact with the first cleaning liquid into contact with a second cleaning liquid having a higher affinity for the removal material than the first cleaning liquid after the step of bringing into contact with the first cleaning liquid.

2. The gas refining method according to claim 1,

the flow rate of the first cleaning liquid is determined based on the temperature of the gas from which the solid particles have been removed after the step of removing the solid particles has been performed.

3. The gas refining method according to claim 1 or 2, wherein,

the first cleaning liquid at least contains water,

the second cleaning liquid contains at least oil.

4. A gas refining device is provided with:

a dust removing part for removing solid particles contained in the gas,

a first scrubber for bringing the gas from which the solid particles have been removed by the dust removing unit into contact with a first cleaning liquid having a temperature lower than a melting point of a removing substance contained in the gas, and

and a second scrubber for bringing the gas treated by the first scrubber into contact with a second cleaning liquid having a higher affinity for the removal substance than the first cleaning liquid.

5. The gas refining apparatus of claim 4,

the first cleaning liquid at least contains water,

the second cleaning fluid at least contains oil.

6. The gas refining apparatus of claim 5,

there is a water supply portion that supplies the drain water generated by the second scrubber to the first scrubber.

7. The gas refining apparatus of claim 5 or 6,

having a tar settling tank that stores the drainage produced by the first scrubber and the drainage produced by the second scrubber.

8. The gas refining apparatus according to any one of claims 4 to 7,

the first scrubber has therein a means for removing material from the gas.