JP6573261B2 - Supercritical water gasification system - Google Patents

Description

  The present invention relates to a supercritical water gasification system in which a slurry body prepared by adding water and a catalyst to biomass is decomposed in a supercritical state to generate fuel gas.

  In recent years, in the technology of gasifying hydrous biomass (shochu residue, egg-collecting chicken manure, sewage sludge, etc.) with supercritical water, utilizing the heat of the product obtained by gasifying biomass with supercritical water, A supercritical water gasification system having a double-pipe heat exchanger that heats hydrous biomass gasified with supercritical water or a slurry body of the biomass has been developed (see, for example, Patent Documents 1 and 2). ).

  Here, a general biomass gasification system includes a heat exchanger, a heater, a gasification reactor, and the like, and organic substances are converted into hydrogen, methane, ethane, carbon monoxide, carbon dioxide, etc. by hydrolysis. Gasify. For example, a heat exchanger is a device that heats a slurry-like slurry body. This slurry body is adjusted by adding water and activated carbon (catalyst) to biomass such as shochu residue, egg-collecting chicken manure, and sludge and mixing them. The heater is a device that raises the temperature of the slurry heated by the heat exchanger to a gasification reaction temperature of 600 ° C. The gasification reactor is a device that hydrothermally processes the slurry to gasify the organic matter to produce a supercritical high-temperature fluid. The fluid in the supercritical state is then separated into gas and liquid, and the gas component is used as fuel gas.

JP 2007-271146 A JP 2009-242697 A

  However, in the supercritical water gasification system as described above, there are fine powders of non-metallic catalyst (for example, activated carbon) used as a catalyst during gasification, tar char generated during gasification, and the like. There is a case where a blockage occurs between the outer tube and the inner tube in the double tube of the double tube heat exchanger.

  Specifically, for example, the post-treatment fluid after the gasification reaction is subjected to heat exchange with the slurry body in a double tube heat exchanger having a total length of about 100 m, so that the water temperature is lowered from about 600 ° C. to about 120 ° C. Thereafter, it is further cooled and separated into gas and waste water by gas-liquid separation. The gas is used as fuel, and the surplus gas is accumulated in the tank and used separately.

  At this time, in such a double tube heat exchanger, the heat of the processed fluid is used for heating the raw material. However, in the middle part of the double-pipe heat exchanger, the temperature difference becomes small due to the relationship between water properties, and heat exchange becomes inefficient. This is because the raw material pressure is higher than the post-treatment fluid pressure, so the raw material pseudocritical point temperature is higher than the post-treatment fluid pseudocritical point temperature. This is because the temperature difference between the processed fluid and the raw material becomes small in a large range in the vessel, and the amount of exchange heat per unit area decreases. This is also caused by a large change in density near the pseudocritical temperature.

  Moreover, in order to withstand high temperature and high pressure, heat exchangers are expensive because engineers who have cleared legal regulations perform welding using thick pipes of expensive materials. Therefore, there is a desire to increase the temperature efficiently using a heat exchanger as small as possible. For example, in the case of a heat exchanger having a long overall length, it takes time to increase the temperature. And since tar and char are generated in the middle temperature part and the high temperature part, if the reaction time here becomes longer, the amount of tar generated increases, which in turn increases the risk of the piping being blocked at the outlet of the heat exchanger. There was a problem.

In order to solve the above problems, a supercritical water gasification system according to the present invention is:
A gasification reactor that gasifies the slurry body produced by preparing biomass with supercritical water, and heat exchange that preheats the slurry body before it is gasified with supercritical water in the gasification reactor. And a gasification system for generating a fuel gas by decomposing the slurry body in a supercritical state,
A heating section for discharging steam at a pressure equal to or higher than the supercritical water gasification system pressure used for preheating the slurry body in the heat exchanger;
A circulation channel connected to circulate between the heating unit and the heat exchanger;
A circulation pump that is disposed downstream of the heat exchanger in the circulation channel and circulates the steam; and
The discharged from the heating unit, the steam to preheat the slurry body in the heat exchanger, characterized in that circulating between the heat exchanger and the heating unit via the circulation passage.

  The present invention has been made in view of the above problems, and a slurry body containing hydrous biomass is preheated using a high-pressure steam higher than the supercritical water gasification system pressure in a heat exchanger. By circulating high-pressure steam, while minimizing fuel consumption, the heat exchanger can be made compact, tar and char generation can be suppressed, and the heat exchanger piping can be prevented from being blocked, An object of the present invention is to provide a supercritical water gasification system capable of more efficiently generating fuel gas such as methane and hydrogen from hydrous biomass.

In order to solve the above problems, a supercritical water gasification system according to the present invention is:
A gasification reactor that gasifies the slurry body produced by preparing biomass with supercritical water, and heat exchange that preheats the slurry body before it is gasified with supercritical water in the gasification reactor. And a gasification system for generating a fuel gas by decomposing the slurry body in a supercritical state,
A heating section that discharges steam at a pressure higher than the supercritical water gasification system pressure;
A circulation channel connected to circulate between the heating unit and the heat exchanger;
A circulation pump disposed in the circulation flow path for circulating the steam,
The steam discharged from the heating unit and preheating the slurry body in the heat exchanger circulates between the heating unit and the heat exchanger via the circulation channel.

Moreover, the supercritical water gasification system according to the present invention is:
Different heat exchanger is further provided with the heat exchanger, produced in those heat exchangers, the temperature was preheating the slurry body by using the steam decreases, generated by the gasification reactor It is good also as cooling a thing.

  The preheat treatment in the heat exchanger is preferably performed under conditions of a temperature of 600 ° C. and a pressure of 25 MPa in consideration of hydrothermal treatment in the reactor.

  According to the present invention, the slurry body containing hydrous biomass is preheated by circulating and using high-pressure steam above the supercritical water gasification system pressure in the heat exchanger, thereby minimizing fuel consumption. , The heat exchanger can be made compact, tar and char production can be suppressed, and the piping of the heat exchanger can be prevented from being blocked, and fuel gas such as methane and hydrogen can be generated more efficiently from hydrous biomass A supercritical water gasification system can be provided.

It is a figure which shows schematic structure of the supercritical water gasification system demonstrated as one Embodiment of this invention. It is a figure which shows schematic structure of the supercritical water gasification system demonstrated as other embodiment of this invention. It is a figure which shows schematic structure of the supercritical water gasification system demonstrated as other embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The objects, features, advantages, and ideas of the present invention will be apparent to those skilled in the art from the description of the present specification, and those skilled in the art can easily reproduce the present invention from the description of the present specification. it can. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments and drawings of the invention described below show preferred embodiments of the present invention and are shown for illustration or explanation, and are not intended to limit the present invention thereto. Absent. It will be apparent to those skilled in the art that various modifications can be made based on the description of the present specification within the spirit and scope of the present invention disclosed herein.

== Overall configuration of supercritical water gasification system according to the present invention ==
FIG. 1 is a diagram showing a schematic configuration of a supercritical water gasification system described as an embodiment of the present invention. As shown in FIG. 1, the supercritical water gasification system according to the present invention (hereinafter sometimes simply referred to as “system” as appropriate) includes a regulating tank 100, a crusher 110, a supply pump 120, a first heat Exchanger 130, second heat exchanger 131, third heat exchanger 132, decompression device 133, supercritical pressure boiler 140, gasification reactor 141, reactor burner 142, boiler water cooling wall 143, superheater 144, gas-liquid A separator 170, a gas tank 171, a catalyst recovery unit 172, a feed water pump 180, and the like are provided. Between the supply pump 120 and the first heat exchanger 130, between the first heat exchanger 130 and the gasification reactor 141 and gas The conversion reactor 141 and the second heat exchanger 131 and the second heat exchanger 131 and the third heat exchanger 132 are connected by pipes, respectively.

  In the case of this embodiment, in this system, the supercritical pressure boiler 140, the first heat exchanger 130, and the second heat exchanger 131 are connected by a circulation flow path 150. The circulation channel 150 includes a boiler feed water circulation pump 161 and the like. And between the supercritical pressure boiler 140, the 1st heat exchanger 130, and the 2nd heat exchanger 131, high-pressure steam more than the supercritical water gasification system pressure sent out from the supercritical pressure boiler 140 (for details, (Described later) is circulated by a boiler feed water circulation pump 161. The above-described configuration of the circulation channel 150 is an example, and the present invention is not limited to this.

  Furthermore, in the case of the present embodiment, the first heat exchanger 130 (that is, the heat exchanger that preheats the slurry body before being gasified with supercritical water in the gasification reactor 141), the second heat exchanger 131. (I.e., a heat exchanger that cools the product produced by the gasification reactor 141 using steam whose temperature has been reduced by preheating the slurry body), the third heat exchanger 132 (i.e., the gasification reactor). 141, the product sent through the second heat exchanger 131 through the second heat exchanger 131 is cooled to almost room temperature), each of which is composed of a double-pipe heat exchanger. It is not limited to.

  The adjustment tank 100 is a tank that mixes hydrous biomass (may be a biomass slurry. The same applies hereinafter), a non-metallic catalyst, water, and the like. The slurry body to be treated in this system is a mixture of the hydrous biomass and non-metallic catalyst introduced into the adjustment tank 100, and water, if necessary, to suspend the non-metallic catalyst on the hydrous biomass. Prepared by becoming cloudy. In addition, the injection | pouring of water is suitably performed according to the moisture content of biomass. The hydrous biomass is, for example, shochu residue, egg-collecting chicken manure, sewage sludge, and the like. In addition, as the non-metallic catalyst, for example, activated carbon, zeolite, a mixture thereof, or the like can be used, but it is preferable to use a powder having an average particle size of 200 μm or less, and porous particles having an average particle size of 200 μm or less. It is more preferable to use

  The crusher 110 crushes the biomass in the slurry body prepared in the adjustment tank 100 so that the biomass has a uniform size (preferably an average particle size of 800 μm or less, more preferably an average particle size of 300 μm or less). It is a device for.

  The supercritical pressure boiler 140 as a heating unit includes a water cooling wall 143 and a superheater 144, and superheats the steam circulated and supplied by the boiler feed water circulation pump 161 through the circulation channel 150. Then, high-pressure steam that is higher than the supercritical water gasification system pressure generated by such overheating is supplied to the first heat exchanger 130.

  The gasification reactor 141 is a non-metal suspended in a slurry body prepared by adding water and a non-metallic catalyst to water-containing biomass in the adjustment tank 100, or in a slurry body crushed by a crusher 110. This is an apparatus for gasifying a biomass in a slurry body with supercritical water using a system catalyst as a catalyst. Gasification of biomass with supercritical water can be performed under the conditions of a temperature of 374 ° C. or higher and a pressure of 22.1 MPa or higher using the above-mentioned nonmetallic catalyst. It is preferable to carry out at a temperature and pressure (in the range of 600 ° C. or more and 25 to 35 MPa) that can suppress and increase the carbon gasification rate. By treating the biomass with supercritical water in this way, the biomass can be decomposed and a fuel gas such as hydrogen gas, methane, ethane, or ethylene can be generated.

  The gasification reactor 141 includes a temperature measurement device that measures the internal fluid temperature and the external combustion gas temperature, and a pressure measurement device that measures the internal fluid pressure and the inlet / outlet differential pressure of the gasification reactor 141 ( (Both not shown).

  In the case of this embodiment, the gasification reactor 141 is provided with a reactor burner 142, and coiled piping is heated by the reactor burner 142. When such a tubular reactor is used, there is an advantage that the reaction time can be secured for a certain time by adjusting the diameter and length of the pipe. In addition, as a gasification reactor, it is not limited to this, If it is an apparatus which can hydrothermally heat the slurry body containing biomass on the above-mentioned conditions, it will not restrict | limit in particular. Other gasification reactors include a catalyst bed reactor, a fluidized bed reactor, and a spouted bed reactor.

  The first heat exchanger 130 configured as a double-pipe heat exchanger has high-pressure steam (in this case, a temperature of 600 ° C.) higher than the supercritical water gasification system pressure supplied from the supercritical pressure boiler 140. The slurry body in which the nonmetallic catalyst is suspended in the hydrous biomass that is gasified with supercritical water in the gasification reactor 141 using the heat of steam of 25 MPa pressure) at a predetermined temperature. This is a device that preheats (preheats) up to (600 ° C. in this case).

  Here, in the conventional double-pipe heat exchanger, the temperature difference is small in the middle part due to the relationship of water properties (that is, the raw material pressure is higher than the pressure of the treated fluid, so that the pseudo-criticality of the raw material (The point temperature is higher than the pseudocritical point temperature of the treated fluid, but water has the largest constant pressure specific heat at the pseudocritical point, so the temperature difference between the treated fluid and the raw material becomes small in a large range in the heat exchanger) For this reason, the amount of heat exchanged per unit heat transfer area is reduced, and heat exchange may become inefficient.

  In addition, in the conventional double-pipe heat exchanger, since the overall length is long to increase the heat exchange efficiency, it takes time to increase the temperature, tar and char are generated in the middle temperature part and the high temperature part, and Due to the longer reaction time, the amount of tar generated increases, and as a result, the piping may be blocked in the heat exchanger or at the outlet thereof.

  Therefore, in the present system, in the first heat exchanger 130, high-pressure steam higher than the supercritical water gasification system pressure supplied from the supercritical pressure boiler 140 (in this case, a temperature of 600 ° C. and a pressure of 25 MPa) The slurry body was preheated using the steam from below. That is, the first heat exchanger 130 can preheat the slurry supplied to the gasification reactor 141 so that the slurry body is closer to 600 ° C. before being gasified with supercritical water in the gasification reactor 141. .

  Specifically, although not shown in the drawing, the double pipe in the first heat exchanger 130 is composed of an outer pipe and an inner pipe in the same manner as the existing double pipe heat exchanger, The steam flows through the flow path in the inner pipe, and the steam flows through the flow path between the outer pipe and the inner pipe. That is, the slurry body flows through the flow path in the inner pipe and is supplied to the gasification reactor 141. The flow path between the outer pipe and the inner pipe is opposite to the direction in which the slurry body flows, A first heat exchanger 130 is provided in the system so that steam flows and is supplied to the second heat exchanger 131.

  In this way, in the first heat exchanger 130, the slurry body is preheated using the high-pressure steam that is higher than the supercritical water gasification system pressure supplied from the supercritical pressure boiler 140, so that the first heat The exchanger 130 can be greatly downsized as compared with the conventional case. Moreover, generation | occurrence | production of tar and char can be suppressed, it can avoid that the piping of the 1st heat exchanger 130 is obstruct | occluded, and fuel gas, such as methane and hydrogen, can be produced | generated more efficiently from hydrous biomass. It is like that. Moreover, since the steam is circulated by the boiler feed water circulation pump 161 through the circulation flow path 150, it can be easily generated as compared with the case where steam is generated from water, so that fuel consumption can be minimized. .

  The second heat exchanger 131 functioning as a cooler is a device for cooling the exhaust gas supplied from the gasification reactor 141 via the first heat exchanger 130. In the second heat exchanger 131, heat is exchanged between the steam after preheating the slurry discharged from the first heat exchanger 130 and the exhaust (that is, the product generated by the gasification reactor 141). Thus, the effluent is cooled from a temperature condition of 600 ° C. to a temperature condition of 150 ° C. to 200 ° C.

  Similarly, the third heat exchanger 132 that functions as a cooler is a device for cooling the discharged matter supplied from the second heat exchanger 131. In this third heat exchanger 132, the water supplied from the supply pump 180 and the above discharge are heat-exchanged, so that the discharge is changed from a temperature condition of 150 ° C. to 200 ° C. to a condition at a substantially normal temperature. Allow to cool.

  The decompression device 133 is disposed between the third heat exchanger 132 and the gas-liquid separator 170 and is discharged from the gasification reactor 141 through the second heat exchanger 131 and the third heat exchanger 132. The effluent is depressurized in this case from a pressure of 25 MPa to approximately atmospheric pressure. In this system, the exhaust gas discharged from the gasification reactor 141 contains highly flammable fuel gas (for example, hydrogen, methane, ethane, ethylene, etc.), water vapor, etc., so it is cooled and decompressed. Thus, it plays a role of reducing the risk or converting water vapor into water to facilitate gas-liquid separation.

  In the present embodiment, the second heat exchanger 131 and the third heat exchanger 132 are described as examples of the apparatus for cooling the exhaust discharged from the gasification reactor 141. However, as the cooler, Is not limited to the second heat exchanger 131 or the third heat exchanger 132, and any device can be used as long as it can cool the exhaust discharged from the gasification reactor 141. Also good. Similarly, the decompressor is not limited to the decompressor 133.

  Further, the heat exchanger described above is not limited to the countercurrent type, and may be, for example, a cocurrent type. Furthermore, the heat exchanger is not limited to a double tube heat exchanger, and may be, for example, a spiral type or plate type heat exchanger.

  Furthermore, by providing pressure gauges (not shown) on the inlet side and outlet side of the boiler feedwater circulation pump 161 in the circulation channel 150, or by providing a differential pressure gauge (not shown) or a flow meter in the circulation channel 150, a closed loop can be used. You may make it confirm that the vapor | steam began to circulate within a certain circulation flow path 150. FIG.

  As described above, by providing the first to third heat exchangers 130 to 132 in the system, energy can be used effectively, so that fuel gas can be generated from hydrous biomass at low energy and low cost. . Moreover, since the heating time in the gasification reactor 141 is significantly shortened by providing the first heat exchanger 130, fuel gas can be efficiently generated from hydrous biomass. Therefore, it can be said that the present system including at least the first heat exchanger 130 (when the second heat exchanger 131 and the third heat exchanger 132 are included) is excellent in economic efficiency.

  The gas-liquid separator 170 converts the exhaust gas supplied through the gasification reactor 141, the second heat exchanger 131, and the third heat exchanger 132 in order into a gaseous component containing a product gas such as fuel gas, Alternatively, the apparatus separates the ash and the nonmetallic catalyst into liquid components suspended in water. As this gas-liquid separator 170, an existing gas-liquid separator such as a separator can be used.

  The gas tank 171 is a container (preferably a pressure-resistant container) that stores a gas component (product gas) separated by the gas-liquid separator 170.

  The superheater 144 arranged in the supercritical pressure boiler 140 was stored in the gas tank 171 with the temperature of the steam sent from the feed water pump 150 and heated by the water cooling wall 143 or the steam heated by the second heat exchanger. This is a pipe group for heat exchange for further raising the combustion gas in a gas containing oxygen, part of the generated gas (fuel gas) or fuel gas (LNG, LPG, etc.). Further, the supercritical pressure boiler 140 is heated by using combustion heat in a gas containing oxygen, part of the generated gas (fuel gas) stored in the gas tank 171 or fuel gas (LNG, LPG, etc.). By heating the first heat exchanger 130 with the steam described above, the slurry body in which the nonmetallic catalyst is suspended in the hydrous biomass is preliminarily heated to a predetermined temperature (in this case, 600 ° C.). The fuel of the supercritical pressure boiler 140 is not limited to gas fuel, but may be solid fuel such as coal or woody biomass, or liquid fuel such as heavy oil or light oil.

  The supply pump 120 is a device that supplies the first heat exchanger 130 with the slurry body prepared in the adjustment tank 100 or the slurry body with the biomass crushed by the crusher 110. The slurry body is supplied to the gasification reactor 141 through the first heat exchanger 130 (the flow path in the inner pipe of the double pipe). As the supply pump 120, for example, a plunger pump, a piston pump, a diaphragm pump, or the like can be used.

  For example, the steam turbine 190 is disposed in a boiler in a thermal power plant (not shown), and is connected to the present system (specifically, the superheater 144 in the supercritical pressure boiler 140) via a heat transfer tube. . Then, steam is generated in the heat transfer pipe by using the heat of the steam discharged from the supercritical pressure boiler 140, thereby rotating the steam turbine 190, and a generator 191 connected coaxially with the steam turbine 190. Will generate electricity by operating. The steam after rotating the steam turbine 190 is condensed by a condenser 192. Although not shown in the figure, after being condensed by the condenser 192, it may be led again into the condenser 192 through the third heat exchanger 132, for example.

  Although not shown in the present embodiment, the present system may be provided with a power generation device that generates power by using the generated gas (fuel gas) stored in the gas tank 171 as fuel. In this case, as the power generation device, for example, existing devices such as a gas engine (reciprocating engine, rotary engine), a gas turbine, a Stirling engine, and a fuel cell can be widely applied.

  Moreover, since the biomass polymer aggregate can be individually decomposed by providing a pretreatment device for hydrothermally treating hydrous biomass in advance in the present system, the fluidity is increased and the gasification reactor 141 performs the treatment. The contact efficiency between the generated biomass and water or a non-metallic catalyst is increased, and the generation of char and tar can be further suppressed, and the fuel gas can be efficiently generated from the biomass.

  Furthermore, by providing the system with the second and third heat exchangers 131 and 132, the gas-liquid separator 170, etc., the generated gas containing the fuel gas can be safely discharged from the exhaust gas discharged from the gasification reactor 141. It can be recovered.

  Moreover, since the biomass can be previously crushed by providing the system with the crusher 110 that crushes the biomass, the efficiency of biomass slurrying and gasification can be increased.

  Furthermore, by using the fuel gas obtained by this system to generate electricity with a gas engine, it is possible to obtain electric power and exhaust heat, so it is possible to save resources for fossil fuels such as coal and oil. become.

  Further, a heater (not shown) is provided between the first heat exchanger 130 and the gasification reactor 141 in this system, and the slurry body transferred from the first heat exchanger 130 to the gasification reactor 141 is provided. By heating (preheating), a state in which the slurry body is less than 600 ° C. due to a temperature drop or insufficient temperature rise is avoided, and the slurry body is reliably kept at 600 ° C. with respect to the gasification reactor 141. It may be transferred.

  As described above, this system includes a gasification reactor 141 for gasifying a slurry body in which a slurry body containing hydrous biomass is suspended with supercritical water, and the gasification reactor 141 for supercritical water. And a first heat exchanger 130 for preheating the slurry body before being gasified by a supercritical pressure boiler as a heating unit that discharges steam at a pressure higher than the supercritical water gasification system pressure. 140, a circulation passage 150 connected to circulate between the supercritical pressure boiler 140 and the first heat exchanger 130, and a circulation pump disposed in the circulation passage 150 for circulating steam. 161, and the first heat exchanger 130 preheats by circulating high-pressure steam that is higher than the supercritical water gasification system pressure delivered from the supercritical pressure boiler 140, thereby minimizing fuel consumption. While holding down The exchanger 130 can be made more compact than before, and tar and char generation can be suppressed, and the piping of the first heat exchanger 130 can be prevented from being blocked. Fuel gas such as hydrogen can be generated more efficiently.

  In addition, the supercritical pressure boiler 140 as a heating part is not restricted to embodiment mentioned above, For example, as shown in FIG. 2 which attached | subjected the same code | symbol to the corresponding part with FIG. 1, gasification reactor 141 is shown. It is good also as heating the gasification reactor 141 using the combustion of the said supercritical pressure boiler 140 comprised. In this case, it is not necessary to separately provide a heating means for heating the gasification reactor 141 (for example, the reactor burner 142), and the configuration of the entire system can be simplified.

  The supercritical pressure boiler 140 as a heating unit may heat the gasification reactor 141 using the heat of the steam discharged from the supercritical pressure boiler 140. At this time, the gasification reactor 141 is provided with a coil-like heating pipe supplied with steam from the supercritical pressure boiler 140, either outside (outer peripheral surface) or inside (inner peripheral surface) of the gasification reactor 141. It is preferable to arrange | position in. In this case, since steam having a pressure equal to or higher than the supercritical water gasification system pressure discharged from the supercritical pressure boiler 140 can be effectively used as a heat source, the gasification reactor 141 can be efficiently heated.

  In addition, the supercritical pressure boiler 140 may use the generated gas extracted from the product generated by the gasification process as a fuel. In this case, since the generated gas generated by the gasification process can be effectively used, energy saving can be achieved.

  Further, as shown in FIG. 2 or FIG. 3 in which parts corresponding to those in FIG. 1 are assigned the same reference numerals, the circulation flow path 150 is provided with an inlet cooler 160, a pressure adjustment pump 162, an accumulator 163, and a pressure adjustment valve 164. It may be.

  The inlet cooler 160 disposed in the circulation channel 150 is a device for cooling using cooling water to avoid cavitation that occurs when the temperature of the steam flowing through the circulation channel 150 is too high. It is. The boiler feed water circulation pump 161 is a device for circulating the above-described steam discharged from the supercritical pressure boiler 140 in the circulation flow path 150. The pressure adjustment pump 162 is a device that adjusts the pressure in the circulation flow path 150 when the system is started up. The pressure of the piping system that sends the fluid to the supercritical pressure boiler 140 through the second heat exchanger 131 is adjusted. In addition, it is maintained above the specified pressure by injecting pure water. The accumulator 163 is for suppressing the pressure pulsation and circulating the aforementioned steam in a constant flow. The pressure adjustment valve 164 adjusts the pressure in the circulation flow path 150 and corresponds to the increase in specific volume at the time of temperature rise. In addition, when the temperature of the vapor | steam which distribute | circulates in this circulation flow path 150 is low enough, the inlet cooler 160 does not need to be installed.

  Further, the drive source for rotating the steam turbine 190 in the steam turbine 190 is not limited to the heat of the steam discharged from the supercritical pressure boiler 140. For example, in addition to the heat of the steam exhausted from the supercritical pressure boiler 140, the first heat exchanger 130 and the second heat exchanger 130 and the second heat exchanger 130, as shown in FIG. The steam turbine 190 may be rotated by generating steam in the heat transfer tube using the heat of the steam supplied from the superheater 144 via the heat exchanger 131 in order.

  Furthermore, the present system generates the gas generated by the gasification process by supplying the above-mentioned steam whose temperature is lowered by preheating the slurry body in the first heat exchanger 130 to the second heat exchanger 131 and using it. It is good also as cooling a thing.

  The preheat treatment in the first heat exchanger 130 is preferably performed under conditions of a temperature of 600 ° C. and a pressure in the range of 25 MPa to 35 MPa in consideration of the hydrothermal treatment in the gasification reactor 141.

  Moreover, as mass ratio of a nonmetallic catalyst and biomass (dry biomass) at the time of preparing the mixture which mixed biomass, a nonmetallic catalyst, and water with the adjustment tank 100, it exists in the range of 1: 1-20. It is preferable that it is in the range of 1: 1-5 where the gasification efficiency of biomass is high. Moreover, it is preferable to adjust the quantity of the water to mix so that the moisture content of biomass may be 70-99 wt%. Thereby, the gasification efficiency by the supercritical water of biomass can be improved.

  Furthermore, a heater (not shown) is provided between the first heat exchanger 130 and the gasification reactor 141, and the slurry transferred from the first heat exchanger 130 is more reliably heated to 600 ° C. (preheating). You may make it do.

  The conditions for the hydrothermal treatment of the biomass slurry supplied to the gasification reactor 141 are not particularly limited as long as the temperature is 374 ° C. or higher and the pressure is 22.1 MPa or higher. It is preferable to carry out at a temperature (600 ° C.) and pressure (within a range of 25 to 35 MPa) that can suppress the generation of tar and char and increase the reaction efficiency. To 600 ° C. and 25 MPa. When it is desired to control the ratio of components in the fuel gas converted from biomass, the temperature and pressure conditions are adjusted, and the fluid density and reaction time (retention of biomass in the gasification reactor 141) are adjusted. This is possible by controlling the time).

  Thus, by reacting the biomass slurry body with supercritical water, it becomes possible to generate combustion gas from the biomass slurry body. In addition, by reducing the biomass from a polymer in advance, the contact efficiency with water or a non-metallic catalyst can be increased, and furthermore, the gasification reaction time of the biomass can be shortened. Fuel gas such as hydrogen gas, methane, ethane, and ethylene can be generated more efficiently from the slurry body.

  The product gas generated by hydrothermally treating the biomass slurry in the gasification reactor 141 is discharged from the gasification reactor 141. This exhaust is cooled in the second heat exchanger 131 by providing heat to the steam supplied from the first heat exchanger 130, and further cooled in the third heat exchanger 132, and then the reduced pressure. The pressure is reduced by the apparatus 133, and the liquid is transferred to the gas-liquid separator 170. The exhaust gas supplied to the gas-liquid separator 170 is separated into a product gas (gas component) containing fuel gas and water or a mixed solution (liquid component) containing water, ash, non-metallic catalyst, etc. The generated gas is stored in the gas tank 171. When the mixed liquid separated by the gas-liquid separator 170 contains ash other than water, a nonmetallic catalyst, or the like, the mixed liquid is ashed by the catalyst recovery unit 172, the nonmetallic catalyst, and Alternatively, it may be separated into water and the nonmetallic catalyst may be recovered. Thereby, it becomes possible to reuse the nonmetallic catalyst.

  The generated gas (fuel gas) stored in the gas tank 171 is supplied to the supercritical pressure boiler 140, the superheater 144, and the reactor burner 142. The supercritical pressure boiler 140, the superheater 144, and the reactor burner 142 use the supplied product gas as fuel, for example, burn in oxygen-containing gas, and circulate through the circulation channel 150, or gasification reaction The vessel 141 is heated. At this time, the steam having a pressure equal to or higher than the supercritical water gasification system pressure generated in the supercritical pressure boiler 140 is supplied to the first heat exchanger 130, so that the hydrous biomass slurry body has a predetermined temperature (600). Preheat to around ℃).

  Further, the product gas is fueled by a burner installed in the boiler, for example, exhaust gas obtained by burning in a gas containing oxygen is supplied to the gasification reactor 141 to provide heat to the slurry body. You may do it. The exhaust gas that has provided heat to the gasification reactor 141, and the exhaust gas obtained by burning the product gas in a gas containing oxygen, for example, by a burner installed in the boiler, for example, is a supercritical pressure boiler. 140 is discharged.

  On the other hand, after preheating the aforementioned slurry body in the first heat exchanger 130, the steam supplied to the second heat exchanger 131 absorbs heat from the product generated in the gasification reactor 141. After the product is cooled, the product is transferred again to the supercritical pressure boiler 140 and is heated through the water cooling wall 143, the boiler, and the superheater 144 provided in the supercritical pressure boiler 140, and then the first The slurry is supplied to the heat exchanger 130 to preheat the slurry body.

  Examples of the nonmetallic catalyst used in the present embodiment include activated carbon, zeolite, and a mixture thereof. The catalyst may be a metal catalyst or an alkali catalyst.

  In addition, when the biomass to be treated in the present embodiment is wastewater sludge or manure containing foreign substances such as sand, a known separation technique (for example, a strainer) is performed before the preheat treatment in the first heat exchanger 130. The foreign substances such as sand contained in the biomass may be removed by a separation method using the method described above, or a separation method using a sedimentation layer. As a result, troubles caused by foreign matters such as sand can be prevented.

  Further, in the first heat exchanger 130 described above, the slurry body is preheated by using high-pressure steam that is higher than the supercritical water gasification system pressure supplied from the supercritical pressure boiler 140, so that the first heat The exchanger 130 can be greatly downsized as compared with the conventional case. Moreover, generation | occurrence | production of tar and char can be suppressed, it can avoid that the piping of the 1st heat exchanger 130 is obstruct | occluded, and fuel gas, such as methane and hydrogen, can be produced | generated more efficiently from hydrous biomass. .

100 adjustment tank 110 crusher 120 supply pump 130 first heat exchanger (heat exchanger)
131 Second heat exchanger 132 Third heat exchanger 133 Pressure reducing device 140 Supercritical pressure boiler (heating unit)
141 Gasification reactor 142 Reactor burner 143 Water cooling wall 144 Superheater 150 Circulation flow path 160 Inlet cooler 161 Boiler feed water circulation pump 162 Pressure adjustment pump 163 Accumulator 164 Pressure adjustment valve 170 Gas-liquid separator 171 Gas tank 172 Catalyst recovery unit 180 Feed water Pump 190 Steam turbine 191 Generator 192 Condenser

Claims (4)

A gasification reactor that gasifies the slurry body produced by preparing biomass with supercritical water, and heat exchange that preheats the slurry body before it is gasified with supercritical water in the gasification reactor. And a gasification system for generating a fuel gas by decomposing the slurry body in a supercritical state,
A heating section for discharging steam at a pressure equal to or higher than the supercritical water gasification system pressure used for preheating the slurry body in the heat exchanger;
A circulation channel connected to circulate between the heating unit and the heat exchanger;
A circulation pump that is disposed downstream of the heat exchanger in the circulation channel and circulates the steam; and
The superheated steam discharged from the heating unit and preheating the slurry body in the heat exchanger circulates between the heating unit and the heat exchanger via the circulation channel. Critical water gasification system.   A heat exchanger different from the heat exchanger is further provided, and in the heat exchanger, a product generated by the gasification reactor using the steam whose temperature is reduced by preheating the slurry body. The supercritical water gasification system according to claim 1, wherein the gas is cooled. The heating unit is
A supercritical pressure boiler for discharging the steam;
The supercritical water gasification system according to claim 1, further comprising a reactor burner for heating the gasification reactor.   The supercritical water gasification system according to claim 3, wherein the supercritical pressure boiler uses a product gas extracted from a product produced by the gasification process as a fuel.

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