JP7351349B2 - Gas purification method and gas purification device - Google Patents

Description

The present disclosure relates to a gas purification method and a gas purification apparatus. This application claims the benefit of priority based on Japanese Patent Application No. 2019-217726 filed on December 2, 2019, the contents of which are incorporated into this application.

As a technique for purifying gas, an exhaust gas treatment facility including a bag filter and an oil scrubber has been disclosed (for example, Patent Document 1). In the technique of Patent Document 1, a bag filter removes dust from the gas. The oil scrubber removes organic compounds from the gas by bringing cleaning oil into contact with the gas from which dust has been removed by the bag filter. The oil scrubber includes a gas-liquid contact portion that brings cleaning oil into contact with gas. The cleaning oil that has come into contact with the gas is supplied again to the gas-liquid contact section, thereby circulating through the oil scrubber.

Japanese Patent Application Publication No. 2006-21187

The oil scrubber removes organic compounds from the gas, such as tar, olefin, and organic halides, by dissolving them in cleaning oil. However, among tars, when heavy tar with a relatively high dew point is dissolved in cleaning oil, the viscosity of the cleaning oil increases.

This makes it difficult to circulate the cleaning oil to the oil scrubber, making it impossible to operate the oil scrubber. Therefore, there is a problem in that it is necessary to frequently replace the cleaning oil with new oil, resulting in increased costs. Therefore, there is a need for the development of technology that can purify gas at low cost.

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

In order to solve the above problems, a gas purification method according to an embodiment of the present disclosure includes a step of removing solid particles contained in a gas, a gas from which the solid particles have been removed, and a removed substance contained in the gas. After carrying out the step of contacting the first cleaning liquid, which has a temperature lower than the dew point of The gas obtained by performing the steps of contacting the oil scrubber with the second cleaning liquid containing at least the second cleaning liquid, exhausting the gas after contacting the second cleaning liquid from the upper part of the oil scrubber, and bringing the first cleaning liquid into contact with the gas. The second cleaning liquid after being in contact with the gas obtained by performing the steps of discharging condensed water generated by the contact with the second cleaning liquid to the outside from the bottom of the oil scrubber and contacting the first cleaning liquid. The method includes a step of discharging the cleaning liquid to the outside from between the top and bottom of the oil scrubber, and a step of supplying the second cleaning liquid discharged to the outside to the oil scrubber.

Further, the flow rate of the first cleaning liquid may be determined depending on the temperature of the gas from which the solid particles are removed after performing the step of removing the solid particles.

In order to solve the above problems, a gas purification device according to one aspect of the present disclosure includes a dust removal section that removes solid particles contained in gas, a gas from which the solid particles have been removed by the dust removal section, and a gas purification device that removes solid particles from the gas. A first scrubber that contacts a first cleaning liquid that is lower in temperature than the dew point of the contained removal substance and that contains at least water; and a second scrubber that brings the gas treated by the first scrubber into contact with a second cleaning liquid that contains at least oil. 2 scrubbers, a first pipe connected to the top of the second scrubber to exhaust the gas after contacting the second cleaning liquid, and a first pipe connected to the bottom of the second scrubber to exhaust the gas processed by the first scrubber and the second pipe connected to the bottom of the second scrubber. A second pipe is connected between the top and bottom of the second scrubber and a second pipe that discharges condensed water generated by contact with the cleaning liquid to the outside, and the second pipe is connected between the top and bottom of the second scrubber and It includes a third pipe that discharges the cleaning liquid to the outside, and a pump that supplies the second cleaning liquid discharged by the third pipe to the second scrubber.

Further, the gas purification device may include a water supply unit that supplies waste water generated in the second scrubber to the first scrubber.

Further, the gas purification device may include a tar decanter that stores the waste water generated in the first scrubber and the waste water generated in the second scrubber.

Moreover, 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, gas can be purified at low cost.

FIG. 1 is a diagram illustrating a gasification gas production apparatus. FIG. 2 is a diagram illustrating the gas purification apparatus. FIG. 3 is a flowchart illustrating the process flow of the gas purification method. FIG. 4 is a diagram illustrating an oil circulation section and a regeneration section according to a modification.

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in these embodiments are merely examples for easy understanding, and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to omit redundant explanation, and elements not directly related to the present disclosure are omitted from illustration. do.

[Gasification gas production device 100]
FIG. 1 is a diagram illustrating a gasification gas production apparatus 100. Note that in FIG. 1, solid arrows indicate the flow of solids (fluid medium, raw materials, and residue) and liquid (water). Further, in FIG. 1, broken line arrows indicate the flow of gas (steam, 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 device 200.

The gasification gas production apparatus 100 gasifies raw materials using a fluidized bed of a fluidized medium to produce gasification gas (synthesis gas). The raw material is, for example, a solid raw material such as coal (brown coal, etc.), biomass (wood pellets, etc.). The gasification gas production apparatus 100 is a circulating fluidized bed gasification system. That is, the gasification gas production apparatus 100 circulates a fluidized medium as a heat medium through the combustion furnace 110, the cyclone 120, and the gasification furnace 150. The fluidizing 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 cylindrical shape. Fuel and fluidized medium are introduced into the combustion furnace 110 through a pipe 112 from a gasification furnace 150, which will be described later. Piping 112 connects the lower part of combustion furnace 110 and gasification furnace 150. The combustion furnace 110 burns fuel and heats the fluidized medium to 600°C or more and 1000°C or less. The flue gas and the fluidized medium heated in the combustion furnace 110 are sent to the cyclone 120 through the pipe 114. Piping 114 connects the upper part of combustion furnace 110 and cyclone 120.

The cyclone 120 separates the mixture of fluidized medium and combustion exhaust gas introduced from the combustion furnace 110 through the pipe 114 into solid and gas. The hot fluidized medium separated by the cyclone 120 is introduced into the gasifier 150 through the pipe 122. Piping 122 connects the bottom of cyclone 120 and gasifier 150.

The hot fluidized medium is fluidized in gasifier 150 by fluidizing gas (eg, steam). Specifically, the gasifier 150 includes a storage tank 152 and a steam introduction section 154. The storage tank 152 stores the fluid medium and raw materials.

The water vapor introduction section 154 introduces water vapor into the storage tank 152. The steam introduction section 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 ventilation plate. Boiler 154b generates water vapor. Boiler 154b is connected to wind box 154a. Steam generated by the boiler 154b is introduced into the wind box 154a. The water vapor introduced into the wind 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 wind box 154a at a flow rate that allows a fluidized bed of the fluidized medium to be formed in the storage tank 152. Therefore, the hot fluidized medium introduced from the cyclone 120 is fluidized by the water vapor. As a result, a fluidized bed (for example, a bubbling fluidized bed) of the fluidized medium is formed in the storage tank 152.

Further, raw materials are introduced into the gasification furnace 150 (accommodation tank 152) through the piping 122. The introduced raw material is gasified by the heat of 600° C. or more and 900° C. or less that the fluidizing medium has, thereby producing gasified gas (synthesis gas). Gasified gas produced in the gasifier 150 is introduced into the cyclone 160 through a pipe 156. Piping 156 connects the upper part of gasifier 150 and cyclone 160.

The cyclone 160 separates the gasified gas discharged from the gasifier 150 into solid and gas. The solid-gas separated gasified gas is introduced into the heat exchanger 170 through the pipe 162. Piping 162 connects the upper part of cyclone 160 and heat exchanger 170. Further, the solid matter (fluidized medium, raw material residue, some tar) that has been separated into solid and gas is introduced into the combustion furnace 110 through the pipe 164 and the pipe 112. Piping 164 connects the bottom of cyclone 160 and piping 112. Note that in this embodiment, the raw material is also introduced into the pipe 164.

The heat exchanger 170 exchanges heat between the gasified gas separated into solid and gas by the cyclone 160 and steam, high-pressure water, and the like. The heat exchanger 170 recovers the sensible heat of the gasified gas using water vapor, 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 a gas purification device 200, which will be described later, through a pipe 172. The specific configuration of the gas purification device 200 will be described in detail later. Piping 172 connects heat exchanger 170 and gas purification device 200 (dust removal section 210).

As described above, the fluidized medium fluidized in the gasifier 150 is returned to the combustion furnace 110 through the pipe 112 that connects the gasifier 150 and the combustion furnace 110. In this way, in the gasification gas production apparatus 100 according to the present embodiment, the fluidized medium moves through the combustion furnace 110, the cyclone 120, and the gasification furnace 150 in this order, and is reintroduced into the combustion furnace 110, thereby Cycle through these.

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

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

The bag filter 140 removes dust from the combustion exhaust gas introduced from the heat exchanger 130 through the piping 132. Piping 132 connects heat exchanger 130 and bag filter 140. The combustion exhaust gas from which dust has been removed by the bag filter 140 is denitrified by a denitrification device (not shown). The denitrified combustion exhaust gas is desulfurized by a desulfurization device (not shown). The desulfurized combustion exhaust gas is exhausted to the outside. Note that the denitrification device and the desulfurization device can also be omitted.

As described above, the gasifier 150 gasifies the raw material at 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 some of the tar contained in the gasification gas is separated by the cyclone 160, most of the tar is entrained in the gasification gas and introduced into the heat exchanger 170. Further, the gasified gas includes ash derived from raw materials and solid particles (dust) such as fluidized media.

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

[Gas purification device 200]
FIG. 2 is a diagram illustrating the gas purification apparatus 200. Note that in FIG. 2, broken line arrows indicate the flow of gasification gas. Further, in FIG. 2, solid line arrows indicate the flow of liquids (first cleaning liquid, drainage water, second cleaning liquid, and drainage oil).

As shown in FIG. 2, the gas purification device 200 includes a dust removal section 210, a water scrubber 220, an oil scrubber 230, a mist separator 240, an induction fan 250, a tar decanter 260, a tar discharging facility 270, and a water circulation system. section 280 and an oil circulation section 290. The dust removal section 210, water scrubber 220, oil scrubber 230, and mist separator 240 are in communication with each other. Furthermore, the mist separator 240 is connected to the suction side of the induction fan 250. Therefore, when the induction fan 250 is driven, the gasified gas passes through the dust removal section 210, the water scrubber 220, the oil scrubber 230, and the mist separator 240 in this order.

The dust removal unit 210 is configured with one or more of a bag filter, a ceramic filter, and a cyclone, for example. Dust removal section 210 is connected to heat exchanger 170 through piping 172. The dust removal section 210 removes some of the 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 equal to or similar to heavy oil. Light tar has a lower boiling point than heavy tar. Light tar contains as a main component an aromatic compound having one or two aromatic rings (benzene, toluene, xylene, naphthalene, etc.). The dust removal section 210 removes a portion of heavy tar.

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

The water scrubber 220 (first scrubber) brings the gasified gas from which solid particles have been removed by the dust removal section 210 into contact with the first cleaning liquid. The first cleaning liquid has a temperature lower than the dew point of heavy tar (removed substance) contained in the gasification 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 this embodiment, the water scrubber 220 includes a main body 220a and a spray section 220b. The main body 220a has a cylindrical shape. A pipe 222 is connected to the upper part of the main body 220a. Piping 222 connects water scrubber 220 and oil scrubber 230. A pipe 282 is connected to the bottom of the main body 220a. Piping 282 connects water scrubber 220 and tar decanter 260. A pipe 212 is connected between the connection point of the pipe 222 and the connection point of the pipe 282 in the main body 220a. Therefore, the gasified gas introduced from the pipe 212 rises inside the main body 220a and is exhausted from the pipe 222.

The spray part 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 section 220b sprays the first cleaning liquid into the main body 220a.

Therefore, the gasified gas comes into contact with the first cleaning liquid during 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 manner, the water scrubber 220 cools the gasified gas to 80° C. or more and less than 100° C., thereby making it possible to condense heavy tar while maintaining fluidity. This allows the water scrubber 220 to move the heavy tar together with the first cleaning liquid to the tar decanter 260 under its own weight. That is, the water scrubber 220 can easily move heavy tar to the tar decanter 260.

Further, the water scrubber 220 maintains the gasified gas at 80° C. or higher. Thereby, the water scrubber 220 can avoid a situation where naphthalene is deposited on the inner wall of the main body 220a.

Furthermore, ammonia and sulfur oxides (SOx) are dissolved in the first cleaning liquid. Thus, if the gasification gas includes 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 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, one or more of mineral oil, light oil, biodiesel fuel, and vegetable oil. The oil scrubber 230 causes light tar contained in the gasification gas to be dissolved in the second cleaning liquid by bringing the gasification gas into contact with the second cleaning liquid. Thereby, the oil scrubber 230 removes light tar from the gasification gas.

In this embodiment, the oil scrubber 230 includes a main body 230a, a dispersion section 230b, and a filled layer 230c. The main body 230a has a cylindrical shape. A pipe 232 is connected to the upper part of the main body 230a. Piping 232 connects oil scrubber 230 and mist separator 240. A pipe 234 is connected to the bottom of the main body 230a. Piping 234 connects oil scrubber 230 and 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. Piping 292 connects oil scrubber 230 and pump 294. A 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 inside the main body 230a and is exhausted from the pipe 232.

The dispersion section 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 (for example, 50° C. or lower) at which water vapor contained in the gasification gas condenses into the main body 230a.

Therefore, the gasified gas comes into contact with the second cleaning liquid while passing through (rising) the main body 230a. Thereby, light tar contained in the gasification gas is dissolved in the second cleaning liquid. The light tar dissolved in the second cleaning liquid then falls to the bottom of the main body 230a.

Further, the gasified gas is cooled by the second cleaning liquid. The water vapor remaining in the gasification gas is then 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. Note that the condensed water has a higher mass density than the second cleaning liquid and the waste oil containing light tar. Therefore, the condensed water stays below the layer of waste oil at the bottom of the main body 230a. That is, in the main body 230a, waste oil and condensed water are separated by sedimentation.

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

Further, the gasified gas from which 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 section 230b and the connection point with the pipe 222 in the main body 230a. The filling layer 230c includes a ring, a wire mesh, a shelf, a tray, and the like. The filling layer 230c reduces the falling speed of the second cleaning liquid. Since the oil scrubber 230 includes the packed bed 230c, it is possible to improve the contact efficiency between the gasification gas and the second cleaning liquid. Therefore, the oil scrubber 230 can efficiently dissolve light tar contained in the gasified gas into the second cleaning liquid.

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

The induction fan 250 is connected to the piping 242 (mist separator 240) on its suction side, and connected to the piping 252 on its discharge side. The induction fan 250 sucks the gasified gas (refined gasified gas) from which the mist has been removed by the mist separator 240, and sends it through the piping 252 to the subsequent gasified gas utilization equipment. The 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 waste water generated in the water scrubber 220 and the condensed water generated in the oil scrubber 230. The tar decanter 260 separates the waste water into supernatant liquid and sediment based on the difference in mass density and particle size. The sediment contains heavy tar.

The tar discharging equipment 270 is composed of, for example, a screw conveyor. The tar discharging equipment 270 sends out the sediment (heavy tar) separated in the tar decanter 260 to the outside. Heavy tar (removal material) is used as fuel for combustion equipment (equipment) such as boilers and generators, and is used to deter animals.

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

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

The oil circulation section 290 circulates the second cleaning liquid to the oil scrubber 230. Oil circulation section 290 includes pipes 292 and 296, a pump 294, and a cooling section 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. Piping 296 connects the discharge side of pump 294 and dispersion section 230b of oil scrubber 230. The pump 294 supplies the waste oil retained in the main body 230a of the oil scrubber 230 to the dispersion section 230b as a second cleaning liquid. Cooling section 298 is provided in piping 296 . The cooling unit 298 cools the second cleaning liquid. With the configuration including the cooling section 298, the oil scrubber 230 can efficiently dissolve light tar contained in the gasified gas into the second cleaning liquid.

[Gas purification method]
Next, a gas purification method using the gas purification apparatus 200 will be explained. FIG. 3 is a flowchart illustrating the process flow of the gas purification method. As shown in FIG. 3, the gas purification method includes a dust removal step S110, a water washing step S120, and an oil washing step S130. Each step will be explained in detail below.

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

[Water washing step S120]
The water cleaning step S120 is a step in which the water scrubber 220 brings the gasified gas from which solid particles have been removed in the dust removal step S110 into contact with the first cleaning liquid. By performing 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 heavy tar has been removed in the water cleaning step S120 into contact with the second cleaning liquid. By performing the oil cleaning step S130, light tar is removed from the gasified gas.

As explained above, the gas purification device 200 of this embodiment and the gas purification method using the same include the dust removal section 210. Thereby, the processing load on the water scrubber 220 can be reduced. Therefore, in the gas purification apparatus 200, the water scrubber 220 and the tar decanter 260 can be made smaller.

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

Furthermore, in the conventional technique of purifying gasification gas using only the oil scrubber 230, not only light tar but also heavy tar dissolves in the second cleaning liquid. Since heavy tar has a high dew point , when it is dissolved in the second cleaning liquid, the viscosity of the second cleaning liquid increases. This makes it difficult to circulate the second cleaning liquid to the oil scrubber 230, making it impossible to operate the oil scrubber 230. Therefore, in the conventional technique of purifying gasification gas using only the oil scrubber 230, the second cleaning liquid had to be replaced frequently.

On the other hand, the gas purification device 200 includes a water scrubber 220 upstream of the oil scrubber 230. Thereby, the oil scrubber 230 brings the second cleaning liquid into contact with the gasified gas from which heavy tar has been removed. Light tar does not increase in viscosity compared to heavy tar even when dissolved in the second cleaning liquid. Therefore, the oil circulation section 290 can stably circulate the second cleaning liquid through the oil scrubber 230. Therefore, the gas purification device 200 can reduce the frequency of replacing the second cleaning liquid compared to the conventional technology that includes only the oil scrubber 230. Thereby, the gas purification device 200 can purify gasified gas at low cost.

Furthermore, the conventional technique of purifying gasified gas using only the oil scrubber 230 cannot remove water-soluble impurities. For this reason, in the conventional technique of refining gasification gas using only the oil scrubber 230, water-soluble impurities may cause problems in the gasification gas utilization equipment at the subsequent stage that utilizes the gasification gas. On the other hand, since the gas purification device 200 includes the water scrubber 220 in addition to the oil scrubber 230, it is possible to remove not only tar but also water-soluble impurities from the gasified gas. Therefore, the gas purification apparatus 200 can prevent malfunctions in the subsequent gasification gas utilization equipment that utilizes the gasification gas.

Further, the gas purification device 200 includes a tar decanter 260. Thereby, the gas purification device 200 can separate heavy tar from waste water. Therefore, the gas purification device 200 can effectively utilize heavy tar.

The gas purification device 200 also includes a water supply section (piping 234, tar decanter 260, and water circulation section 280). Thereby, the gas purification device 200 can utilize the waste water generated by the oil scrubber 230 in the water scrubber 220. Therefore, the gas purification device 200 can reduce the cost required for the first cleaning liquid.

The gas purification device 200 also includes a dust removal section 210, a water scrubber 220, and an oil scrubber 230. Therefore, the gas purification device 200 can efficiently remove tar from the gasification gas even if the oxidation reforming furnace that has been conventionally used to remove tar contained in the gasification gas is omitted. The oxidation reformer adds oxygen and air to the gasified gas generated in the gasifier 150, and combusts a portion of the gasified gas. Therefore, by omitting the oxidation reforming furnace, the gas purification apparatus 200 can increase the amount of combustion gas (hydrogen, carbon monoxide) contained in the gasified gas after purification.

[Modified example]
The gas purification device 200 may further include a regeneration unit that regenerates the second cleaning liquid used in the oil scrubber 230. FIG. 4 is a diagram illustrating an oil circulation section 310 and a regeneration section 350 according to a modification. Note that in FIG. 4, broken line arrows indicate the flow of gas (gasification gas, bottom gas, and distillate gas). Further, in FIG. 4, solid arrows indicate the flow of liquids (condensed water, second cleaning liquid, waste oil, bottoms, and distillate).

As shown in FIG. 4, the oil circulation section 310 includes a sedimentation separation section 320, piping 322, 330, 334, 336, a pump 332, a heat exchanger 340, and a cooling section 298. Note that components that are substantially the same as those of the oil circulation section 290 are given the same reference numerals and descriptions thereof will be omitted.

The sedimentation separation section 320 separates waste oil and condensed water generated by the oil scrubber 230. The sedimentation separation section 320 includes a storage tank 320a and a partition plate 320b. The storage tank 320a stores waste oil and condensed water generated by the oil scrubber 230. The partition plate 320b partitions 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 and lower portions of the partition plate 320b are connected to the inner wall of the storage tank 320a.

Piping 234 connects the bottom of main body 230a of oil scrubber 230 and the first chamber of storage tank 320a. Therefore, the waste oil and 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 storage tank 320a, condensed water settles and is separated from the waste oil. The precipitated and separated condensed water is introduced into the tar decanter 260 through the piping 322. Piping 322 connects the bottom of the first chamber of storage tank 320a and tar decanter 260.

On the other hand, the waste oil separated by settling of the condensed water in the first chamber overflows the partition plate 320b and moves to the second chamber of the storage tank 320a. The waste oil is then introduced into the suction side of the pump 332 through the pipe 330. The discharge side of pump 332 is connected to piping 334 . Piping 334 connects the discharge side of pump 332 and regeneration section 350 (regeneration tower 352). The pump 332 introduces the waste oil separated by the sedimentation separation section 320 into the regeneration section 350. The regeneration unit 350 regenerates waste oil. In other words, the regeneration unit 350 removes light tar from the waste oil. The specific configuration of the reproduction section 350 will be detailed later.

The waste oil (second cleaning liquid) regenerated by the regeneration section 350 is supplied to the dispersion section 230b of the oil scrubber 230 through the pipe 336.

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

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 inside the regeneration tower 352. The packed bed includes trays. Piping 334 is connected to the center of regeneration tower 352. The reboiler 354 extracts bottoms from the bottom of the regeneration tower 352 and heats it to a predetermined temperature. The bottom gas that is heated by the reboiler 354 and vaporized from the bottom liquid is returned to the regeneration tower 352 . On the other hand, the bottom liquid from which bottom gas has been removed by the reboiler 354 is introduced into the pipe 336 as a 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 portion of the distillate condensed by the condenser 356 is extracted to the outside, and the remainder is returned to the regeneration tower 352. The distillate contains light tar.

The oil scrubber 230 removes light tar from the gasification gas by dissolving it in the second cleaning liquid. Therefore, in the oil scrubber 230, as the operating time becomes longer, the amount of light tar accumulated in the second cleaning liquid increases, and the second cleaning liquid deteriorates. Therefore, the modified example includes a playback section 350. Thereby, light tar can be removed from the waste oil and reused by the oil scrubber 230. Therefore, in the modified example, it is possible to further reduce the frequency of replacing the second cleaning liquid.

Although the embodiments have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to the above embodiments. It is clear that those skilled in the art can come up with various changes and modifications within the scope of the claims, and it is understood that these naturally fall within the technical scope of the present disclosure. be done.

For example, in the embodiment described above, the case where the gas purification apparatus 200 purifies the gasified gas produced by the gasification furnace 150 was exemplified. However, the gas purification device 200 can purify gas containing solid particles and organic compounds such as tar and olefins. The gas purification device 200 may purify gas produced by a device that steams (carbonizes) raw materials, such as a lime kiln or a coke oven. Further, the gas purification device 200 may purify exhaust gas from a paint factory.

Furthermore, in the above embodiment, the gasifier 150 has been described using as an example a configuration in which a solid raw material is gasified in a fluidized bed of a fluidized medium. However, the gasifier 150 only needs to be able to gasify the solid raw material using the heat possessed by the fluidized medium. Gasifier 150 may, for example, gasify solid feedstock with a moving bed of fluidized medium.

Further, in the above embodiment, the gas purification device 200 is provided with a water supply unit that supplies waste water generated in the oil scrubber 230 to the water scrubber 220 as an example. However, the gas purification device 200 does not have to supply the waste water generated in the oil scrubber 230 to the water scrubber 220.

Furthermore, in the embodiment described above, the gas purification device 200 includes the tar decanter 260 as an example. However, the gas purification device 200 may not include the tar decanter 260.

Further, in the above embodiment, the gas purification device 200 includes the induction fan 250 as an example. However, the induced fan 250 is not an essential component. For example, if the gas can pass through the dust removal section 210, the water scrubber 220, and the oil scrubber 230 in this order due to the pressure difference, the induction fan 250 can be omitted.

Alternatively, an acid may be added to the first cleaning liquid sprayed by the water scrubber 220 to make the first cleaning liquid acidic. Thereby, the water scrubber 220 can efficiently remove alkaline components (for example, ammonia) contained in the gas. Similarly, an alkali may be added to the first cleaning liquid sprayed by the water scrubber 220 to make the first cleaning liquid alkaline. Thereby, the water scrubber 220 can efficiently remove acid components (for example, sulfur oxides) contained in the gas.

Furthermore, the water circulation unit 280 may include a mechanism for extracting waste water and a mechanism for replenishing the first cleaning liquid. Similarly, the oil circulation section 290 may include a mechanism for extracting waste oil and a mechanism for replenishing the second cleaning liquid.

Furthermore, in the embodiment described above, the gas purification device 200 may include a sedimentation separation section 320 that separates waste oil and condensed water generated by the oil scrubber 230.

Furthermore, in the embodiment described above, the configuration in which the dispersion section 230b sprays the second cleaning liquid into the main body 230a has been exemplified. However, the configuration of the dispersion section 230b is not limited as long as it can substantially uniformly disperse the second cleaning liquid over the horizontal section of the main body 230a. The dispersion section 230b may include, for example, a dispersion material.

Further, in the above embodiments and modified examples, the piping 234 may be provided with a pump. Further, in a modified example, a pump may be provided in the piping 336 and the condenser 356.

Further, in the above embodiment, the first cleaning liquid contains at least water as an example. However, the structure of the first cleaning liquid is not limited as long as the temperature is lower than the dew point of the substance to be removed contained in the gas. The first cleaning liquid is, for example, one or both of methanol and ethanol. The gas purification device 200 can efficiently remove the substance to be removed by bringing the first cleaning liquid, which is lower in temperature than the dew point of the substance to be removed, into contact with the gasification gas.

In the above embodiment, tar containing an aromatic compound was also exemplified as the removal substance. However, the removal material may also include olefins.

Further, the flow rate of the first cleaning liquid supplied by the water scrubber 220 may be determined depending on the temperature or flow rate of the gasified gas exhausted from the bag filter 140. For example, the controller includes a temperature measurement unit that measures the temperature of the gasified gas exhausted from the bag filter 140 or the temperature inside the water scrubber 220, and the control unit controls the water scrubber 220 based on the measurement result of the temperature measurement unit. A flow rate of the first cleaning liquid to be supplied is determined. In this case, the control unit preferably determines the flow rate of the first cleaning liquid supplied by the water scrubber 220 so that the temperature inside the water scrubber 220 is below the dew point of heavy tar and above the dew point of light tar. Thereby, the control unit can make the temperature of the gas at the outlet of the water scrubber 220 lower than the dew point of heavy tar, and it is possible to improve the removal rate of heavy tar.

Further, in the above embodiment, the water scrubber 220 includes the spraying section 220b as an example. However, the configuration of the water scrubber 220 is not limited as long as it can bring the gasified gas from which solid particles have been removed by the dust removal section 210 into contact with the first cleaning liquid. The water scrubber 220 may have a similar configuration to the oil scrubber 230, and may include a dispersion material, for example.

The present disclosure can be used in a gas purification method and a gas purification device.

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

Claims (6)

a step of removing solid particles contained in the gas;
bringing the gas from which the solid particles have been removed into contact with a first cleaning liquid that is lower in temperature than the dew point of the removed substance contained in the gas and that contains at least water;
After performing the step of bringing the first cleaning liquid into contact, a step of bringing the gas brought into contact with the first cleaning liquid into contact with a second cleaning liquid containing at least oil in an oil scrubber;
exhausting the gas after contacting the second cleaning liquid from the upper part of the oil scrubber;
a step of discharging condensed water generated by contact between the gas obtained by performing the step of contacting the first cleaning liquid and the second cleaning liquid to the outside from the bottom of the oil scrubber;
a step of discharging the second cleaning liquid to the outside from between the upper part and the bottom part of the oil scrubber after contacting with the gas obtained by performing the step of contacting the first cleaning liquid;
supplying the second cleaning liquid discharged to the outside to the oil scrubber;
gas purification methods including; 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 are removed after performing the step of removing the solid particles. a dust removal section 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 removal unit into contact with a first cleaning liquid that is lower in temperature than the dew point of the removed substance contained in the gas and that contains at least water;
a second scrubber that brings the gas processed by the first scrubber into contact with a second cleaning liquid containing at least oil;
a first pipe connected to the upper part of the second scrubber and exhausting the gas after contacting the second cleaning liquid;
a second pipe that is connected to the bottom of the second scrubber and discharges condensed water generated by contact between the gas processed by the first scrubber and the second cleaning liquid to the outside;
a third pipe connected between the upper part and the bottom part of the second scrubber and discharging the second cleaning liquid to the outside after contacting the gas treated by the first scrubber;
a pump that supplies the second cleaning liquid discharged by the third pipe to the second scrubber;
A gas purification device equipped with. The gas purification device according to claim 3 , further comprising a water supply unit that supplies waste water generated in the second scrubber to the first scrubber. The gas purification apparatus according to claim 3 or 4, further comprising a tar decanter that stores the waste water generated in the first scrubber and the waste water generated in the second scrubber. The gas purification apparatus according to any one of claims 3 to 5 , wherein the first scrubber includes equipment that utilizes a removal substance removed from the gas.

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