JP2014159528A - Synthesis gas generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To omit a device for treating ammonia by effectively utilizing ammonia contained in waste water.SOLUTION: A synthesis gas generation system 100 includes: a combustion furnace 112 for heating a fluid medium; a gasification furnace 116 into which the fluid medium heated by the combustion furnace is introduced to form a fluidized bed and which gasifies a raw material for gasification by the heat of the fluidized bed to generate a synthesis gas X1; a cleaning section 212 for obtaining ammonia water by dissolving ammonia contained in the synthesis gas into water by cleaning the synthesis gas with water; and a concentration section 216 for concentrating the ammonia water to separate it into concentrated ammonia water Z2 and water.

Description

  The present invention relates to a synthesis gas generation system for treating waste water generated by cleaning and purifying synthesis gas generated in a gasification furnace using water.

  In recent years, a technology has been developed that gasifies raw materials such as coal, biomass, and tire chips to generate synthesis gas instead of petroleum. Synthetic gas generated in this way is used for power generation systems, production of synthetic fuel (synthetic petroleum), production of chemical products such as chemical fertilizer (urea), and the like.

As a technique for gasifying a gasification raw material, for example, a technique for gasifying the gasification raw material using water vapor (for example, Patent Document 1) has been developed. In the gasified gas generation system of Patent Document 1, wastewater generated by purifying (cleaning) synthesis gas contains ammonia (NH ₃ ). When the ammonia concentration in the wastewater exceeds the discharge standard value, it is necessary to remove ammonia from the wastewater. Therefore, the gasification gas generation system is provided with an ammonia diffusion tower (ammonia stripping device), and ammonia is removed from the wastewater by vaporizing ammonia in the wastewater in the ammonia diffusion tower. The removed ammonia in the gaseous state is subjected to an oxidation treatment such as combustion and is discarded.

  In addition, wastewater containing ammonia is generally generated in steelworks, and is equipped with an ammonia diffusion tower and an oxidation treatment device, or an activated sludge tank that removes ammonia in the wastewater by microorganisms. To do.

JP 2012-1686 A

  In the gasification gas generation system and the steelworks described above, it is necessary to provide an oxidation treatment apparatus and an activated sludge tank in order to treat the removed ammonia, and there is a problem that equipment costs increase.

  In view of such a problem, an object of the present invention is to provide a synthesis gas generation system capable of omitting an apparatus for treating ammonia by effectively using ammonia in waste water.

  In order to solve the above problems, a synthesis gas generation system of the present invention includes a combustion furnace for heating a fluidized medium, a fluidized medium heated by the combustion furnace is introduced to form a fluidized bed, and the fluidized bed has heat. A gasification furnace that gasifies the gasification raw material in order to generate synthesis gas, and washing the generated synthesis gas with water, so that ammonia contained in the synthesis gas is dissolved in water to obtain ammonia water And a concentrating section for concentrating the ammonia water and separating the water into concentrated ammonia water and water.

  Moreover, it is good also as providing the denitration part which reduce | restores the nitrogen oxide in the combustion exhaust gas produced in the combustion furnace using concentrated ammonia water.

  Moreover, it is good also as providing the water vapor | steam introduction part which vaporizes concentrated ammonia water and introduces it into a gasification furnace.

  The concentration unit may concentrate the aqueous ammonia using a single-stage or multiple-stage reverse osmosis membrane.

  In the present invention, it is possible to omit an apparatus for treating ammonia by effectively using ammonia in waste water.

It is a figure for demonstrating the synthesis gas production | generation system concerning 1st Embodiment. It is a figure for demonstrating the structural example of a concentration part. It is a figure for demonstrating the synthesis gas production | generation system concerning 2nd Embodiment. It is a figure for demonstrating the synthesis gas production | generation system concerning 3rd Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(First embodiment)
FIG. 1 is a diagram for explaining a synthesis gas generation system 100 according to the first embodiment. As shown in FIG. 1, the synthesis gas generation system 100 includes a synthesis gas generation device 110, a synthesis gas purification device 200, an ammonia production device 250, and an ammonia utilization device 260. In FIG. 1, the flow of sand is indicated by an alternate long and short dash line, and the flow of things other than sand, for example, gasification raw material, gas, water, oil, etc. is indicated by solid arrows.

  In the synthesis gas generation system 100, a gasification raw material is gasified at about 700 ° C. to 900 ° C. using steam in a gasification furnace in which a fluid medium forms a fluidized bed (steam gasification). In the synthesis gas generation system 100 in the present embodiment, the ammonia production apparatus 250 uses the purified gas (hydrogen) that is generated by the synthesis gas generation apparatus 110 and purified by the synthesis gas purification apparatus 200. Ammonia water is produced. Then, the ammonia water produced by the ammonia production apparatus 250 is processed into fertilizer or the like by the ammonia utilization apparatus 260.

  The ammonia production apparatus 250 synthesizes ammonia from hydrogen. Moreover, the ammonia utilization apparatus 260 manufactures a fertilizer etc. from ammonia water. Since the technology for synthesizing ammonia from hydrogen by the ammonia production device 250 and the technology for producing fertilizer and the like from the ammonia water by the ammonia utilization device 260 are existing technologies, detailed description thereof is omitted.

  Hereinafter, specific configurations of the ammonia production apparatus 250, the synthesis gas generation apparatus 110 that generates the synthesis gas used in the ammonia utilization apparatus 260, and the synthesis gas purification apparatus 200 will be described in that order.

(Syngas generator 110)
As shown in FIG. 1, the synthesis gas generation apparatus 110 includes a combustion furnace 112, a medium separator (cyclone) 114, a gasification furnace 116, and a water vapor introduction unit 118.

In the synthesis gas generator 110, as a whole, a fluid medium composed of sand such as dredged sand (silica sand) having a particle size of about 300 μm is circulated as a heat medium. Specifically, the fluid medium is first heated to about 1000 ° C. in the combustion furnace 112 and introduced into the medium separator 114 together with the combustion exhaust gas EX containing carbon dioxide (CO ₂ ). In the medium separator 114, the high-temperature fluid medium and the combustion exhaust gas EX are separated, and the separated high-temperature fluid medium is introduced into the gasification furnace 116. Then, the fluidized medium introduced into the gasification furnace 116 is fluidized into layers by a gasifying agent (steam, nitrogen, air, oxygen, inert gas, etc.) introduced from the bottom of the gasification furnace 116, and then finally Thus, it is returned to the combustion furnace 112.

  The gasification furnace 116 is, for example, a bubbling fluidized bed (bubbling fluidized bed) gasification furnace, and generates a synthesis gas by gasifying a gasification raw material at 700 ° C. to 900 ° C. In this embodiment, the steam introduction part 118 comprised with the boiler produces | generates water vapor | steam, and the said steam introduction part 118 introduce | transduces water vapor into the gasification furnace 116, thereby gasifying the gasification raw material and producing | generating synthesis gas. (Steam gasification).

  Here, as a gasification raw material, solid raw materials, such as coal, biomass, and a tire chip, can be used. Examples of coal include peat, lignite, lignite, subbituminous coal, bituminous coal, semi-anthracite, and anthracite. In the present embodiment, low-grade fuel such as lignite is gasified as a gasification raw material.

  And since the synthesis gas X1 produced | generated in the gasification furnace 116 contains tar, water vapor | steam, etc., it is sent to the synthesis gas purification apparatus 200 of a back | latter stage (downstream), and is refine | purified.

  Here, a circulating fluidized bed type gasification furnace 116 will be described as an example. However, if the gasification raw material is a gasification furnace that gasifies a gasification raw material, a simple fluidized bed type gasification furnace, or sand is used as its own weight. It may be a moving bed type gasification furnace that forms a moving bed by flowing down vertically.

(Syngas purification apparatus 200)
The synthesis gas purification apparatus 200 includes a reforming furnace (oxidation reforming furnace) 210, a cleaning unit 212, a sedimentation separation unit 214, and a concentration unit 216.

  The reforming furnace 210 adds oxygen or air to the synthesis gas X1 generated in the gasification furnace 116 to obtain a temperature of about 900 ° C. to 1500 ° C., thereby reforming (oxidation reforming) the tar contained in the synthesis gas X1.

The cleaning unit 212 cleans the synthesis gas X2 whose tar is modified with water, thereby dissolving ammonia contained in the synthesis gas X2 in water to obtain ammonia water (NH ₄ aq). More specifically, the cleaning unit 212 includes a spray tower and a mist separator.

  The spray tower cools the synthesis gas X2 having reached 300 to 600 ° C. to about 70 ° C. by spraying cooling water at about 40 ° C. onto the synthesis gas X2. As a result, the tar and sludge contained in the synthesis gas X2 are condensed, and the ammonia contained in the synthesis gas X2 is dissolved in water and removed from the synthesis gas X2, thereby producing a crude refined gas and an oil mixed water Y. . Then, the spray tower supplies the roughly purified gas to the subsequent mist separator, and sends the oil mixed water Y including ammonia water, tar, and sludge to the sedimentation separation unit 214.

  The mist separator sprays approximately 40 ° C. cooling water onto the crude purified gas as water droplets smaller than the particle diameter in the spray tower. As a result, in the spray tower, the mist-like tar or sludge contained in the crude refined gas that could not be sufficiently separated and removed is condensed, and the ammonia contained in the crude refined gas is dissolved in water. And purified gas X3 and oil mixed water Y are produced. Then, the mist separator supplies the purified gas X3 to the downstream ammonia production apparatus 250 and sends the oil mixed water Y including ammonia water, tar and sludge to the sedimentation separation unit 214.

  By being purified in the synthesis gas purification apparatus 200, the purification gas X3 becomes a gas whose main component is hydrogen, and is synthesized into ammonia by the ammonia production apparatus 250 at the subsequent stage.

  The sedimentation separation unit 214 separates the oil-mixed water Y sent from the washing unit 212 into the supernatant Z1 and the sediment T based on the difference in specific gravity. Then, the sediment T contains tar and sludge, and the supernatant Z1 becomes ammonia water from which the tar and sludge have been removed.

  The sediment T separated and settled by the sedimentation separation unit 214 is returned to the gasification furnace 116 of the synthesis gas generator 110. Since the precipitate T contains a large amount of tar, by returning the precipitate T to the gasification furnace 116, the gas derived from the gasification raw material is used as the gasification raw material to be gasified in the gasification furnace 116. Can do. Accordingly, the sediment T separated and settled in the sedimentation separation unit 214 can be effectively used without being discarded, and the cost required for disposal can be reduced. Further, since the amount of the gasification raw material introduced in the gasification furnace 116 can be reduced, the cost required for the gasification raw material can also be reduced.

  On the other hand, the supernatant Z1 separated by the sedimentation separation unit 214 is sent to the concentration unit 216.

  The concentration unit 216 concentrates the supernatant Z1 (ammonia water) and separates it into concentrated ammonia water Z2 and water. Then, the concentrated ammonia water Z2 separated by the concentration unit 216 is sent to the downstream ammonia utilization device 260, and the separated water (pure water) is delivered to the user.

  FIG. 2 is a diagram for explaining a configuration example of the concentration unit 216. As shown in FIG. 2, the concentration unit 216 according to the present embodiment includes a pump 220, a pre-filter 222, a tank 224, a pump 226 (indicated by 226 a to 226 e in FIG. 2), an ammonia separation unit 230 ( 2, and pumps 234 and 236.

  The pump 220 sends the supernatant Z1 from the sedimentation separation unit 214 to the tank 224. A pre-filter 222 for removing tar and sludge is provided between the pump 220 and the tank 224.

  The pump 226 is composed of, for example, a high-pressure liquid feed pump, and pumps the supernatant Z1 to the ammonia separation unit 230. The ammonia separation unit 230 includes a reverse osmosis membrane 232 disposed therein. The reverse osmosis membrane 232 has a function of passing water and not passing ions. Therefore, when the pump 226 pumps the supernatant Z1 to the ammonia separator 230, only the water in the supernatant Z1 passes through the reverse osmosis membrane 232, and ammonia does not pass through the reverse osmosis membrane 232. In this way, water is separated from the supernatant Z1 by the ammonia separator 230, and concentrated ammonia water Z2 is generated (ammonia water is concentrated).

  As shown in FIG. 2, in this embodiment, ammonia separation units 230 are connected in series in a plurality of stages (here, five stages). Specifically, the pump 226a pumps the supernatant Z1 to the ammonia separator 230a, the pump 226b pumps the concentrated aqueous ammonia concentrated by the ammonia separator 230a to the ammonia separator 230b, and the pump 226c The concentrated ammonia water concentrated in the ammonia separator 230b is pumped to the ammonia separator 230c, the pump 226d pumps the concentrated ammonia water concentrated in the ammonia separator 230c to the ammonia separator 230d, and the pump 226e The concentrated ammonia water concentrated by the separation unit 230d is pumped to the ammonia separation unit 230e. Here, the delivery pressure by the pumps 226a to 226e is, for example, about 0.4 MPa to 1.2 MPa.

  Since the supernatant Z1 and the concentrated ammonia water are constantly pumped to the ammonia separators 230a to 230e by the pumps 226a to 226e, the downstream side of the reverse osmosis membrane 232 in the ammonia separators 230a to 230e is a negative pressure. It becomes. Therefore, even if the pumps 226b to 226e and 234 are driven and the concentrated ammonia water upstream of the reverse osmosis membrane 232 is sent to the next stage, the water moves from the downstream side to the upstream side of the reverse osmosis membrane 232. There is almost no.

In general, since the concentration rate of the reverse osmosis membrane 232 is about twice, it can be concentrated to 2 ⁵ = 32 times by using five stages of the ammonia separation unit 230. That is, the ammonia concentration in the concentrated ammonia water Z2 can be increased by providing the ammonia separation unit 230 in a plurality of stages.

  Further, the concentration unit 216 concentrates the ammonia water with the reverse osmosis membrane 232, so that the ammonia water can be efficiently concentrated.

  The concentrated ammonia water Z2 concentrated in this manner is sent to the downstream ammonia using device 260 by the pump 234, and the separated water (pure water) is sent to the user by the pump 236.

  As described above, according to the synthesis gas generation system 100 according to the present embodiment, in the synthesis gas purification apparatus 200, the ammonia water (supernatant liquid Z1) obtained by washing the synthesis gas X1 is added to the concentration unit. By concentrating 216, concentrated ammonia water Z2 having a concentration that can be used in the downstream ammonia utilization device 260 can be produced.

  Therefore, conventionally discarded ammonia can be used effectively, and an apparatus for treating ammonia can be omitted. Thereby, the installation cost of the apparatus for processing ammonia, such as a diffusion tower and an activated sludge tank, can be reduced. In addition, when the synthetic gas X1 contains almost no BOD (organic matter consumed by living organisms such as activated sludge), it is necessary to add organic matter when performing the activated sludge treatment. According to the synthesis gas generation system 100, an activated sludge tank is not required, and the cost required for organic substances can be reduced.

  Furthermore, in the ammonia utilization device 260, the amount of ammonia that can be used can be increased, so that the production cost of fertilizer and the like can be reduced.

(Second Embodiment)
In the first embodiment described above, the configuration in which the synthesis gas generation system 100 includes the ammonia production device 250 and the ammonia utilization device 260 and the concentrated ammonia water Z2 concentrated by the concentration unit 216 is used in the ammonia utilization device 260 has been described. In the second embodiment, a configuration in which another device uses the concentrated aqueous ammonia Z2 concentrated by the concentration unit 216 will be described.

  FIG. 3 is a diagram for explaining a synthesis gas generation system 300 according to the second embodiment. As shown in FIG. 3, the synthesis gas generation system 300 includes a synthesis gas generation device 310 and a synthesis gas purification device 200. In FIG. 3, the flow of sand is indicated by an alternate long and short dash line, and the flow of things other than sand, for example, gasification raw material, gas, water, oil, etc., is indicated by a solid arrow.

  The synthesis gas purification device 200 has substantially the same function as the synthesis gas purification device 200 of the first embodiment described above, and thus the same reference numerals are given and redundant description is omitted.

  The synthesis gas generator 310 includes a combustion furnace 112, a medium separator 114, a gasifier 116, a water vapor introduction unit 118, and a denitration unit 312. Note that the combustion furnace 112, the medium separator 114, the gasifier 116, and the water vapor introduction unit 118 have substantially the same functions as the constituent elements of the synthesis gas generator 110 of the first embodiment described above, and therefore have the same reference numerals. The redundant description is omitted, and here, the denitration unit 312 will be described in detail.

  The denitration unit 312 includes a denitration catalyst, and the exhaust gas EX is passed through the denitration unit 312. Here, the denitration catalyst is a catalyst composed of a metal such as vanadium, tungsten, molybdenum, or an oxide thereof and titanium oxide, for example.

  Further, the concentrated ammonia water Z2 concentrated by the concentration unit 216 is introduced into the denitration unit 312.

Then, as shown in the following reaction formula (1) or reaction formula (2), in the denitration unit 312, ammonia in the concentrated aqueous ammonia Z2 functions as a reducing agent, and nitrogen oxides in the combustion exhaust gas EX ( NO _x ) can be reduced (decomposed) to nitrogen to form exhaust gas X5 from which nitrogen oxides have been removed from combustion exhaust gas EX.
4NO + 4NH ₃ + O ₂ → 4N ₂ + 6H ₂ O
... Reaction formula (1)
NO + NO ₂ + 2NH ₃ → 2N ₂ + 3H ₂ O
... Reaction formula (2)

As described above, according to the synthesis gas generation system 300 according to the present embodiment, in the synthesis gas purification apparatus 200, the ammonia water (supernatant Z1) obtained by washing the synthesis gas X1 is added to the concentration unit. 216 is concentrated and concentrated concentrated aqueous ammonia Z2, the NO _x in the combustion exhaust gas EX generated in synthesis gas generator 310 can be removed.

When removing NO _x in the combustion exhaust gas EX, the denitration unit 312 requires a reducing agent (for example, urea). However, since the denitration unit 312 uses ammonia that has been discarded as a reducing agent, the cost required for the reducing agent can be reduced, and an apparatus for treating ammonia can be omitted.

(Third embodiment)
In the second embodiment, the configuration in which the synthesis gas generation system 300 includes the denitration unit 312 and the concentrated ammonia water Z2 concentrated by the concentration unit 216 is used in the denitration unit 312 has been described. In the third embodiment, a configuration in which another device uses the concentrated aqueous ammonia Z2 concentrated by the concentration unit 216 will be described.

  FIG. 4 is a diagram for explaining a synthesis gas generation system 400 according to the third embodiment. As shown in FIG. 4, the synthesis gas generation system 400 includes a synthesis gas generation device 410 and a synthesis gas purification device 200. In FIG. 4, the flow of sand is indicated by a one-dot chain line, and the flow of things other than sand, for example, gasification raw material, gas, water, oil, etc. is indicated by a solid line arrow.

  The synthesis gas purification device 200 has substantially the same function as the synthesis gas purification device 200 of the first embodiment described above, and thus the same reference numerals are given and redundant description is omitted.

  The synthesis gas generation apparatus 410 includes a combustion furnace 112, a medium separation apparatus 114, a gasification furnace 116, and a water vapor introduction unit 418. Note that the combustion furnace 112, the medium separator 114, and the gasification furnace 116 have substantially the same functions as the constituent elements of the synthesis gas generation apparatus 110 of the first embodiment described above, and thus are denoted by the same reference numerals and overlapped. The description is omitted, and here, the water vapor introducing section 418 having different functions will be described in detail.

  The steam introduction unit 418 vaporizes the concentrated aqueous ammonia Z2 concentrated by the concentration unit 216 and introduces it into the gasification furnace 116.

  Conventionally, the water vapor introduced into the gasification furnace 116 includes a pH adjusting agent for adjusting the pH in the gasification furnace 116. In the present embodiment, ammonia in the concentrated aqueous ammonia Z2 functions as a pH adjuster, and adjusts the pH in the gasifier 116.

  As described above, according to the synthesis gas generation system 400 according to the present embodiment, the steam introduction unit 418 uses ammonia that has been conventionally discarded as a pH adjusting agent, thereby reducing the cost required for the pH adjusting agent. It can be reduced and an apparatus for treating ammonia can be omitted.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  For example, in the above-described embodiment, a cation exchange resin may be provided between the ammonia separation unit 230 and the pump 236 or on the downstream side of the pump 236. With this configuration, the purity of the water sent from the pump 236 can be improved.

  Further, the synthesis gas generation system 100 described above may include a denitration unit 312 and a water vapor introduction unit 418, and the synthesis gas generation system 300 may include a water vapor introduction unit 418.

  In the above-described embodiment, the case where the sediment T separated and settled by the sedimentation separation unit 214 is described as an example is returned to the gasification furnace 116, but the sediment T is returned to the combustion furnace 112. May be. In this case, the amount of fuel introduced into the combustion furnace 112 can be reduced.

  In the first embodiment described above, the configuration in which the synthesis gas generation system 100 includes the ammonia production apparatus 250 has been described. However, the ammonia production apparatus 250 may not be provided, and at least the ammonia utilization apparatus 260 may be included. .

In the above-described second embodiment, the case where the denitration unit 312 includes a denitration catalyst has been described as an example, but the denitration catalyst is not an essential configuration. For example, high temperature of the combustion exhaust gas EX is, even without the denitration catalyst, if capable of reducing NO _x with concentrated aqueous ammonia Z2, denitration unit 312, without providing a denitration catalyst, and at least flue gas EX concentrated aqueous ammonia Z2 has a function of contacting the door, it is sufficient reducing NO _x in the combustion exhaust gas EX with concentrated aqueous ammonia Z2 (non-catalytic reduction).

  INDUSTRIAL APPLICABILITY The present invention can be used in a synthesis gas generation system that treats wastewater generated by cleaning and purifying synthesis gas generated in a gasification furnace using water.

DESCRIPTION OF SYMBOLS 100, 300, 400 ... Syngas production system 112 ... Combustion furnace 116 ... Gasification furnace 210 ... Reforming furnace 216 ... Concentration part 232 ... Reverse osmosis membrane 312 ... Denitration part 418 ... Steam introduction part

Claims (4)

A combustion furnace for heating the fluid medium;
A gasification furnace in which a fluidized medium heated by the combustion furnace is introduced to form a fluidized bed, and gasified raw material is gasified with heat of the fluidized bed to generate synthesis gas;
A washing unit that obtains ammonia water by washing the generated synthesis gas with water to dissolve ammonia contained in the synthesis gas in the water;
A concentration section for concentrating the aqueous ammonia and separating the aqueous ammonia into water and concentrated ammonia;
A synthesis gas generation system comprising:   The synthesis gas generation system according to claim 1, further comprising a denitration unit that uses the concentrated ammonia water to reduce nitrogen oxides in the combustion exhaust gas generated in the combustion furnace.   The synthesis gas generation system according to claim 1, further comprising a water vapor introduction unit that vaporizes the concentrated ammonia water and introduces the concentrated ammonia water into the gasification furnace.   4. The synthesis gas generation system according to claim 1, wherein the concentration unit concentrates the ammonia water using a single-stage or multiple-stage reverse osmosis membrane. 5.

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