JP6671677B1 - Supercritical water gasification system - Google Patents

Abstract

In the present invention, the first heat exchanger 130 preheats the slurry body containing the hydrous biomass by using the steam from the drum type boiler 140, thereby minimizing the fuel cost and at the same time the first heat exchange. The reactor 130 can be made compact, the generation of tar and char can be suppressed, the piping of the first heat exchanger 130 can be prevented from being blocked, and the fuel gas can be produced more efficiently. Further, when preheating, the flow rate adjustment valve 160 adjusts the flow rate of steam to control the temperature of the slurry body at the outlet of the first heat exchanger 130, so that the temperature rise of the slurry body at the outlet of the first heat exchanger 130. The shortage can be avoided. Therefore, it is possible to eliminate the heater provided between the first heat exchanger 130 and the gasification reactor 141 in the conventional system.

Description

  The present invention relates to a supercritical water gasification system that generates a fuel gas by decomposing a slurry body prepared by adding water and a catalyst to biomass in a supercritical state.

  In recent years, in the technology of gasifying hydrous biomass (shochu residue, egg-collecting chicken manure, sewage sludge, etc.) with supercritical water, the products obtained by supercritical water gasification of hydrous biomass and the heat thereof are used. A supercritical water gasification system equipped with a double-tube heat exchanger for heating hydrous biomass or a slurry of the biomass has been developed (for example, see Patent Documents 1 and 2). The supercritical water is water at 374 ° C. or higher and 22.1 MPa or higher. In this case, the hydrous biomass is a raw material of the fuel gas.

  Here, a general biomass gasification system is configured to include a heat exchanger / heater, a gasification reactor, etc., and hydrolyzes organic substances into hydrogen, methane, ethane, carbon monoxide, carbon dioxide, etc. Gasify. For example, a heat exchanger is a device that heats a slurry body that is adjusted by adding water and activated carbon (gasification catalyst) to biomass such as shochu residue, egg collecting chicken manure, and sewage sludge. The heater is a device that raises the temperature of the slurry heated by the heat exchanger to 600 ° C., which is the gasification reaction temperature. The gasification reactor is a device that hydrothermally treats this slurry body to gasify organic matter and turn it into a supercritical high-temperature fluid. The fluid in the supercritical state is then heat-exchanged to room temperature and separated into gas and liquid, and the gaseous component is used as fuel gas.

JP 2007-271146 A JP 2009-242697 A

  However, in the supercritical water gasification system as described above, fine powder of a nonmetallic catalyst (eg, activated carbon) used as a catalyst during gasification, inorganic matter derived from raw materials, and tar generated during gasification -Due to the char, etc., the inner tube in the double tube of the double tube heat exchanger, or a blockage between the inner tube and the outer tube may occur.

  Specifically, for example, the post-treatment fluid after the gasification reaction flows between the inner tube and the outer tube of the double-tube heat exchanger having a total length of about 100 m, and undergoes heat exchange with the slurry body flowing in the inner tube. After the liquid temperature is lowered, it is further cooled and separated into gas and liquid by gas-liquid separation. The gas is used as fuel, and the surplus gas is stored in a tank and used separately. At this time, in such a double tube heat exchanger, the heat of the treated fluid is used for heating the slurry as the gasification raw material.

  However, in the middle part of the double-pipe heat exchanger, heat exchange becomes inefficient because the temperature difference is reduced due to the physical properties of water, which is the main component of the slurry body. This is because the slurry body pressure becomes higher than the post-processing fluid pressure, and the pseudo critical point temperature of the slurry body in the inner pipe becomes higher than the pseudo critical point temperature of the post-processing fluid between the inner pipe and the outer pipe. Because water has the maximum specific heat at constant pressure at the pseudocritical point, the temperature difference between the fluid and the slurry after treatment is reduced over a wide range in the heat exchanger, and the amount of heat exchanged per unit area is reduced. . In addition, a large change in density near the pseudo critical point temperature is also a cause of this.

  For this reason, tar or char generated from the slurry body flowing in the inner pipe of the double-pipe heat exchanger may cause blockage of the heat exchanger inner pipe and the pipes after the outlet thereof, which may eventually stop the system. was there.

  Further, the heat exchanger is expensive because a technician who has cleared legal regulations by using a thick-walled pipe made of expensive material performs welding in order to withstand high temperature and high pressure. Therefore, there is a demand for efficiently increasing the temperature using a heat exchanger as small as possible. For example, in the case of a long heat exchanger, it takes time to raise the temperature. Then, since tar and char are generated in the middle temperature portion and the high temperature portion, if the reaction time here is prolonged, the amount of tar and char generated increases, which may lead to blockage of the flow path at the inner tube outlet of the heat exchanger. was there.

  Therefore, the present inventors have proposed that, from the viewpoint of preventing the flow passage blockage of the heat exchanger and improving the gasification rate, the slurry body is brought to a temperature close to the gasification reaction temperature and the pressure of the supercritical water gasification system. We focused on preheating using steam at a pressure close to.

  The present invention has been made in view of the above problems, and while minimizing the fuel cost while minimizing the heat exchanger, suppressing the generation of tar and char to avoid clogging the piping of the heat exchanger, It is an object of the present invention to provide a supercritical water gasification system that can more efficiently generate fuel gas such as methane, hydrogen, and carbon monoxide from hydrous biomass.

In order to solve the above problems, a supercritical water gasification system according to the present invention is:
A gasification reactor for supercritical water gasification of a slurry produced by preparing biomass, and a first heat exchange for preheating the slurry before supercritical water gasification in the gasification reactor A supercritical water gasification system comprising a device, wherein the slurry body is decomposed in a supercritical state to generate a fuel gas,
A heating unit having a drum-type boiler for discharging steam used for preheating the slurry body in the first heat exchanger,
Provided in a flow path connecting between the heating unit and the first heat exchanger, comprising a flow rate adjustment unit that controls the flow rate of the steam,
The flow rate adjuster controls a temperature of the slurry body at an outlet of the first heat exchanger by adjusting a flow rate of the steam.

Further, the supercritical water gasification system according to the present invention,
Further comprising a second heat exchanger different from the first heat exchanger,
The first heat exchanger may cool the product of the gasification reactor using the steam whose temperature has been reduced by preheating the slurry body in the first heat exchanger.

The heating unit further includes a water supply pump for supplying water to the drum-type boiler, and a driving turbine for driving the water supply pump,
The driving turbine may be driven using steam after cooling the product in the second heat exchanger.

  The heating unit may further include a circulation channel that circulates water between the drum-type boiler and a water supply channel to the drum-type boiler.

  The drum-type boiler may use the generated gas generated by the gasification process as fuel.

  In addition, in consideration of hydrothermal treatment in a reactor, preheating in a heat exchanger is preferably performed with steam at 538 ° C. to 566 ° C., which is near the reactor temperature of 600 ° C.

  According to the present invention, the slurry body is preheated by using the steam from the heating section in the heat exchanger, so that the heat exchanger can be made compact while minimizing fuel costs, and the heating rate can be increased by making it compact. By improving, it is possible to suppress the production of tar and char, avoid the blockage of the piping of the heat exchanger, and more efficiently generate the fuel gas such as methane, hydrogen, and carbon monoxide from the hydrous biomass.

It is a figure showing the schematic structure of the supercritical water gasification system concerning one embodiment of the present invention. It is a figure showing the schematic structure of the supercritical water gasification system concerning other embodiments.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention can be appropriately modified within a scope that does not contradict the gist or idea of the invention that can be read from the claims and the entire specification, and a supercritical water gasification system with such a change is also provided by the present invention. Included in the technical philosophy.

== 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, may be simply referred to as “system” as appropriate) includes an adjustment tank 100, a crusher 110, a supply pump 120, and a first heat source. Exchanger 130, second heat exchanger 131, third heat exchanger 132, fourth heat exchanger 133, pressure reducing device 134, drum type boiler 140, gasification reactor 141, reactor burner 142, boiler water cooling wall 143, It has a superheater 144, a gas-liquid separator 170, a gas tank 171, a catalyst recovery unit 172, a water supply pump 180, etc., between the supply pump 120 and the first heat exchanger 130, a gasification reaction with the first heat exchanger 130. Between the heat exchanger 141, between the gasification reactor 141 and the second heat exchanger 131, between the second heat exchanger 131 and the third heat exchanger 132, and between the third heat exchanger 132 and the fourth heat exchanger 133. In between, it It is connected by being piping.

  In the case of the present embodiment, in the present system, the drum-type boiler 140, the first heat exchanger 130, and the second heat exchanger 131 are connected by the flow path 150. The flow path 150 includes a flow control valve 160 between the drum-type boiler 140 and the first heat exchanger 130. The steam (details will be described later) sent from the drum-type boiler 140 is circulated between the drum-type boiler 140, the first heat exchanger 130, and the second heat exchanger 131, and is used for each purpose. ing. Note that the configuration of the flow path 150 is an example and is not limited to this.

  Further, in the case of the present embodiment, the first heat exchanger 130 (a heat exchanger for preheating a slurry body before being gasified by supercritical water in the gasification reactor 141), the second heat exchanger 131 (a slurry A heat exchanger that cools and recovers the product of the gasification reactor 141 by utilizing the steam whose temperature has been reduced by preheating the body), a third heat exchanger 132 (second heat from the gasification reactor 141). A heat exchanger that cools the product sent out through the exchanger 131 to 100 ° C. to 150 ° C. and recovers heat, and a fourth heat exchanger 133 (a heat exchanger using water supplied from the condensate pump 193). The heat exchanger which cools the product delivered from the three heat exchangers 132 to almost normal temperature and recovers heat and heat recovery) is described as a case where each is constituted by a double tube heat exchanger. Not exclusively.

  The adjustment tank 100 is a tank for mixing hydrous biomass (a biomass slurry may be used; the same applies hereinafter), a nonmetallic catalyst, water, and the like. The slurry treated by the present system mixes the hydrous biomass and the non-metallic catalyst charged into the adjustment tank 100, and the water charged as necessary, and suspends the non-metallic catalyst on the hydrous biomass. Prepared by turbidity. In addition, input of water is performed suitably according to the water content of biomass. The water-containing biomass is, for example, shochu residue, egg-collecting chicken manure, sewage sludge, and the like. As the nonmetallic catalyst, for example, activated carbon, zeolite, a mixture thereof, or the like can be used. However, it is preferable to use 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 to make the biomass a uniform size in advance (preferably, the average particle diameter is 800 μm or less, more preferably, the average particle diameter is 300 μm or less). It is a device for.

The drum-type boiler 140 as a heating unit is configured to include a water-cooling wall 143, a superheater 144, and a drum 145, and is supplied with water from a water supply pump 180 and preheated through a third heat exchanger 132 to cool water. Heat is generated at the wall 143 to generate steam, and the steam is further heated by the superheater 144 fed through the drum 145. Then, steam of about 538 ° C. to 566 ° C. and about 15 MPa to 20 MPa generated by the overheating is supplied to the first heat exchanger 130. At this time, the feedwater pump 180 is driven by a drive turbine 181 that uses steam (steam after cooling a product generated by the gasification reactor 141) sent from a second heat exchanger 131 described later. You.
The drum-type boiler 140 can use inexpensive fuel such as coal or heavy oil and can generate steam with high boiler efficiency, so that steam can be supplied at low cost.

  The gasification reactor 141 is prepared by adding water or a nonmetallic catalyst to water-containing biomass in the adjusting tank 100 and mixing the slurry, or adding a nonmetallic catalyst to the biomass crushed by the crusher 110 and mixing. This is an apparatus for gasifying biomass in the slurry by subjecting the prepared slurry to supercritical water gasification. The condition is preferably a supercritical state (that is, a condition of 374 ° C. or more and 22.1 MPa or more), but under a temperature and a pressure (600 ° C.) that can suppress the production of tar and char and increase the carbon gasification rate. C. or higher and within the range of 25 to 35 MPa). As described above, biomass is gasified with supercritical water to decompose the biomass and generate a fuel gas such as methane, hydrogen gas, carbon monoxide, ethane, and ethylene.

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

  In the case of the present embodiment, the gasification reactor 141 includes a reactor burner 142, and heats a coiled pipe (not shown) by the reactor burner 142. When such a tubular reactor is used, there is an advantage that a constant reaction time can be secured by adjusting the diameter and length of the pipe. It should be noted that the gasification reactor is not limited to this, and in addition, a catalyst bed reactor, a fluidized bed reactor, a spouted bed reactor and the like can be widely applied. The apparatus is not particularly limited as long as the apparatus can hydrothermally treat the slurry containing biomass under the above-described conditions.

  The first heat exchanger 130 configured as a double-pipe heat exchanger converts heat of steam (in this case, steam at about 538 ° C. to 566 ° C. and about 15 MPa to 20 MPa) supplied from the drum-type boiler 140. This is a device for preheating a slurry in which a nonmetallic catalyst is suspended in hydrous biomass subjected to supercritical water gasification treatment in a gasification reactor 141 to a predetermined temperature (around 600 ° C. in this case). .

  Here, in the conventional double-pipe heat exchanger that exchanges heat between the slurry body and the treated fluid, the temperature difference is small at an intermediate portion due to the physical properties of water. That is, since the slurry body pressure is higher than the post-treatment fluid pressure, the pseudocritical point temperature of the slurry body is higher than that of the post-treatment fluid, and the constant pressure specific heat of water becomes maximum at the pseudocritical point. The temperature difference between the fluid after treatment and the slurry body is reduced in a large range within the range. For this reason, the amount of heat exchanged per unit heat transfer area decreases, and there is a possibility that heat exchange becomes inefficient. It should be noted that a large change in density near the pseudo critical point temperature also causes a decrease in the temperature difference.

  Further, in the conventional double-pipe heat exchanger, it takes a long time to raise the temperature because the entire length is formed so as to increase the amount of heat exchanged. Tar and char are generated in the medium-temperature and high-temperature sections, but if the temperature rises slowly, the time required for tar and char generation increases, resulting in an increase in the amount of the generated tar and char. There was a risk that the piping would be blocked.

  Therefore, in the present system, the first heat exchanger 130 utilizes the steam (in this case, steam at about 538 ° C. to 566 ° C. and steam at about 15 MPa to 20 MPa) supplied from the drum type boiler 140 to form the slurry body. Was preheated. That is, the first heat exchanger 130 can preheat the slurry supplied to the gasification reactor 141 to be closer to 600 ° C. before being gasified by the supercritical water in the gasification reactor 141. .

  Specifically, although not shown, the double pipe in the first heat exchanger 130 is composed of an outer pipe and an inner pipe, like the existing double-pipe heat exchanger, and is provided by the supply pump 120. The fed slurry body flows through a flow path in the inner pipe, and steam supplied from the drum-type boiler 140 flows through a flow path between the outer pipe and the inner pipe. That is, in the first heat exchanger 130, the slurry flows in the flow path in the inner pipe and is supplied to the gasification reactor 141, and the direction in which the slurry flows in the flow path between the outer pipe and the inner pipe. In the opposite direction, the steam flows and is supplied to the second heat exchanger 131.

  In addition, a flow control valve 160 as a flow control unit that controls the flow rate of steam supplied from the drum boiler 140 is provided in the flow path 150 that connects the drum boiler 140 and the first heat exchanger 130. ing. The flow control valve 160 controls the flow rate of steam (steam for preheating the slurry body) supplied from the drum-type boiler 140, thereby controlling the steam (about 538 ° C. to 566 ° C. and about 15 MPa to 20 MPa). The temperature of the steam (in other words, the preheating temperature of the slurry body) is maintained at around 600 ° C. (preferably, about 538 ° C. to 566 ° C.). At this time, it is preferable to provide a thermometer (not shown) at the outlet side of the pipe in the first heat exchanger 130 through which the slurry body from the supply pump 120 flows, and adjust the flow control valve 160. Furthermore, the flow control valve 160 may maintain the steam at about 15 MPa to 20 MPa by controlling the flow rate of the steam supplied from the drum type boiler 140. In this case, the maintenance of the steam pressure has priority over the preheating temperature of the slurry body.

  As described above, the first heat exchanger 130 can be significantly reduced in size by preheating the slurry body using the steam supplied from the drum-type boiler 140 in the first heat exchanger 130. In addition, by increasing the temperature rising rate of the slurry body, the generation of tar and char is suppressed to avoid the clogging of the piping of the first heat exchanger 130, and the fuel gas such as methane, hydrogen, and carbon monoxide is converted from the hydrous biomass. Can be generated more efficiently. Moreover, the steam is sent to a drive turbine 181 and a steam turbine 190 for driving a second heat exchanger 131, a water supply pump 180, and the like, which will be described later, via a flow path 150, and is reused for each purpose. Therefore, the fuel consumption of the entire system can be minimized.

  The second heat exchanger 131 functioning as a cooler is a device for cooling the effluent supplied from the gasification reactor 141 via the first heat exchanger 130 and recovering heat. In the second heat exchanger 131, heat is exchanged between steam after preheating the slurry discharged from the first heat exchanger 130 and the discharge (product generated by the gasification reactor 141). The waste is cooled from 600 ° C. to 150 ° C. to 200 ° C., and heat is recovered for effective use.

  In addition, the third heat exchanger 132, which functions as a cooler similarly to the second heat exchanger 131, cools the effluent supplied from the second heat exchanger 131 and recovers heat to the thermal power generation system side. Device. In the third heat exchanger 132, the effluent is cooled from 150 ° C to 200 ° C to 100 ° C to 150 ° C by exchanging heat with the water supplied from the water supply pump 180. Thereafter, in the fourth heat exchanger 133, the water discharged from the condensate pump 193 exchanges heat with the above-mentioned effluent, whereby the effluent is cooled from 100 ° C. to 150 ° C. to almost normal temperature. Further, the water after cooling the effluent is supplied to the water cooling wall 143 via the deaerator 200, the water supply pump 180, and the third heat exchanger 132, and then heated to form a superheater 144 in a steam state. Sent to

  The decompression device 134 is provided between the fourth heat exchanger 133 and the gas-liquid separator 170, and is provided from the gasification reactor 141 to the second heat exchanger 131, the third heat exchanger 132, and the fourth heat exchanger. In this case, the discharge discharged through 133 is reduced from 25 MPa to a pressure at which gas can be sent to the consuming place and the pressure can be accumulated in the container. In this system, the effluent discharged from the gasification reactor 141 contains highly flammable fuel gas (for example, methane, hydrogen, carbon monoxide, ethane, ethylene), water vapor, etc. The device 134 cools and decompresses the above-mentioned effluent, thereby reducing the risk of fire and the like, and converting water vapor into water to facilitate gas-liquid separation.

  In the present embodiment, a second heat exchanger 131, a third heat exchanger 132, and a fourth heat exchanger 133 are used as examples of a device that cools and recovers heat discharged from the gasification reactor 141. Although described above, the cooler is not limited to these, and any device may be used as long as it can cool the exhaust discharged from the gasification reactor 141. Similarly, the pressure reducing device is not limited to the pressure reducing device 134.

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

  As described above, by providing the first to fourth heat exchangers 130 to 133 in the present system, energy can be used effectively, so that fuel gas can be generated from hydrous biomass with low energy and low cost. In addition, since the rate of temperature increase is greatly improved by the first heat exchanger 130, the gasification reactor 141 can efficiently convert the fuel gas into fuel gas. Therefore, the present system including at least the first heat exchanger 130 (and further including the second heat exchanger 131, the third heat exchanger 132, and the fourth heat exchanger 133) is excellent in economy. .

  The gas-liquid separator 170 converts the effluent sequentially supplied through the gasification reactor 141 and the second to fourth heat exchangers 131 to 133 into product gas (gas component) including fuel gas, water or This is a device that separates water into ash and a liquid component in which a nonmetallic catalyst is suspended. As the 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 the gas component (product gas) separated by the gas-liquid separator 170. The effluent that has been decompressed by the decompression device 134 and transferred to the gas-liquid separator 170 includes a product gas (gas component) including a fuel gas and a mixed liquid (liquid component) of water, ash, a nonmetallic catalyst, and the like. And the generated gas is stored in a gas tank 171. When the mixed solution contains a nonmetallic catalyst, the catalyst may be separated into ash, a nonmetallic catalyst, and water by the catalyst collector 172 to recover the nonmetallic catalyst. This makes it possible to reuse the nonmetallic catalyst.

  The superheater 144 arranged in the drum type boiler 140 is sent from the condensate pump 193 via the fourth heat exchanger 133, the deaerator 200, the water supply pump 180, and the third heat exchanger 132, and is supplied to the water cooling wall 143. Heat for further raising the temperature of the heated steam by using combustion heat in a part of the generated gas stored in the gas tank 171 or a gas containing oxygen such as the atmosphere in a fuel gas (LNG, LPG, etc.). This is a piping group for replacement. Further, the drum type boiler 140 is provided with the above-described steam heated by using combustion heat in a part of the generated gas stored in the gas tank 171 or a gas containing oxygen such as the atmosphere in a fuel gas (LNG, LPG, etc.). By heating the first heat exchanger 130, the slurry body in which the nonmetallic catalyst is suspended in the hydrous biomass is preheated to a predetermined temperature (in this case, around 600 ° C.). The fuel of the drum type 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. At that time, the generated gas may be used together. In addition, the drum-type boiler 140 generates steam while circulating water in the drum 145 between the water-cooling wall 143 and the drum 145, and heats the steam generated through the superheater 144. And transferred to the steam turbine 190.

  The supply pump 120 is a device for supplying the slurry prepared in the adjustment tank 100 or the slurry obtained by crushing the biomass by the crusher 110 to the first heat exchanger 130. The slurry body is supplied to the gasification reactor 141 via the first heat exchanger 130 (the flow path in the inner tube of the double tube). As the supply pump 120, for example, a plunger pump, a high-pressure piston pump, a diaphragm pump, or the like can be used.

  The steam turbine 190 is disposed, for example, in a thermal power plant (not shown), and is connected to the present system (specifically, a superheater 144 in the drum-type boiler 140) via a heat transfer tube. Then, by utilizing the steam of the drum-type boiler 140 and the steam discharged from the second heat exchanger 131, the steam turbine 190 is rotated to generate electric power by the coaxially connected generator 191. Water is condensed in the condenser 192.

  Although not shown in the present embodiment, the present system may include a power generation device that generates power by using the generated 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, a gas turbine, a Stirling engine, and a fuel cell can be widely applied.

  In addition, by providing the system with a pre-treatment device for hydrothermally treating the hydrous biomass in advance, the biomass, that is, the aggregate of the polymer can be individually decomposed, so that the fluidity is increased and the biomass is processed in the gasification reactor 141. Increases the contact efficiency between biomass and water or non-metallic catalysts, further reduces the production of tar and char, and enables efficient production of fuel gas such as methane, hydrogen, and carbon monoxide from biomass .

  As described above, by providing the second to fourth heat exchangers 131 to 133, the gas-liquid separator 170, and the like in the present system, the product gas including the fuel gas is discharged from the effluent discharged from the gasification reactor 141. Can be collected safely.

  Further, by providing the system with the crusher 110 for crushing biomass, the biomass can be crushed in advance, so that the efficiency of biomass slurrying and gasification can be improved.

  Furthermore, by using the fuel gas obtained by this system to generate power using a gas engine, it is possible to obtain electric power and waste heat, so that fossil fuels such as coal and petroleum can be conserved in resources. become.

  Furthermore, in the present system, the heat of the steam discharged from the drum-type boiler 140 is used to preheat the slurry transferred to the gasification reactor 141 in the first heat exchanger 130, thereby reducing the gas. Since the slurry body can be reliably transferred to the gasification reactor 141 in a state near the steam temperature sent from the drum-type boiler 140, a state such as insufficient temperature rise of the slurry body can be avoided. Therefore, a heater provided between the first heat exchanger 130 and the gasification reactor 141 in the conventional system can be eliminated.

As described above, the present system includes a gasification reactor 141 for performing supercritical water gasification of a slurry body containing hydrous biomass, and preheats the slurry body before the slurry body is treated in the gasification reactor 141. A first heat exchanger 130, a drum-type boiler 140 as a heating unit, and a flow control valve 160 for controlling the flow rate of steam are provided. At this time, the flow control valve 160 is provided in the flow path 150 connecting between the first heat exchanger 130 and the drum type boiler 140. Then, the first heat exchanger 130 uses steam (in this case, main steam of about 538 ° C. to 566 ° C. and about 15 MPa to 20 MPa) of the drum type boiler 140 to heat the slurry body flowing through the inner tube. Therefore, it is possible to reduce the fuel cost and to input a larger amount of steam than the slurry body as needed, thereby improving the temperature rising rate of the slurry body and suppressing the generation of tar and char generated from the slurry body, Blockage of the inner tube of the heat exchanger 130 can be prevented.
At this time, since a large amount of heat is supplied when a large amount of steam is supplied, the first heat exchanger 130 can be made compact.

In addition, since methane, hydrogen, carbon monoxide, and the like can be generated from hydrous biomass whose conversion to tar and char is suppressed, fuel gas can be generated more efficiently, and gasification efficiency can be improved.
Furthermore, by cooling the product of the gasification reactor 141 in the second heat exchanger 131 and recovering heat by the steam after heating the slurry body, a further effect of minimizing fuel cost can be expected.

  In addition, the drum-type boiler 140 as a heating unit is not limited to the above-described embodiment, and includes, for example, a gasification reactor 141, and uses the combustion of the drum-type boiler 140 to operate the gasification reactor 141. It may be heated. In this case, there is no need to separately provide a heating unit (for example, the reactor burner 142) for heating the gasification reactor 141, and the configuration of the entire system can be simplified.

  Further, the drum-type boiler 140 serving as a heating unit may heat the gasification reactor 141 using the heat of the above-described steam discharged from the drum-type boiler 140. At this time, in the gasification reactor 141, a coiled heating pipe or the like to which steam is supplied from the drum-type boiler 140 is connected to the outside (outer peripheral surface) or the inside of the coil (not shown) of the gasification reactor 141. (Inner peripheral surface) to form a double pipe. In this case, the steam discharged from the drum type boiler 140 can be effectively used as a heat source, so that the gasification reactor 141 can efficiently heat the slurry body.

  Further, the drive source of the steam turbine 190 is not limited to the steam discharged from the drum-type boiler 140. For example, as shown in FIG. 1, in addition to the steam discharged from the drum-type boiler 140, utilizing the steam and the like sequentially supplied through the first heat exchanger 130 and the second heat exchanger 131, The steam turbine 190 may be driven.

  The mass ratio between the nonmetallic catalyst and biomass (dry biomass) when preparing a mixture of biomass, nonmetallic catalyst, and water in the adjustment tank 100 is in the range of 1: 1 to 20. The range of 1: 1 to 5 where the gasification efficiency of biomass is high is particularly preferable. Further, the amount of water to be mixed is preferably adjusted so that the water content of the biomass is 70 to 99 wt%. Thereby, the gasification rate of biomass can be increased.

  Hydrothermal treatment conditions of the biomass slurry in the gasification reactor 141 are not particularly limited as long as they are supercritical water conditions (374 ° C. or higher and 22.1 MPa or higher). It is preferable to perform the reaction at a temperature (500 ° C. or higher) and a pressure (range of 25 to 35 MPa) at which the gasification rate can be increased. Particularly preferred.

  The product gas stored in the gas tank 171 is supplied to the drum-type boiler 140 and the burner 142 for the reactor and burned. The drum-type boiler 140 / reactor burner 142 burns the supplied product gas as fuel, for example, in a gas containing oxygen, such as air, to generate steam from the water cooling wall 143 and / or the superheater 144, or gasification. The slurry body inside the reactor 141 is heated.

  Further, the combustion gas of the drum type boiler 140 may be supplied to the gasification reactor 141 to heat the slurry body.

  After pre-heating the 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, and After the product is cooled, it is transferred to the drive turbine 181 and the steam turbine 190 and used for driving the drive turbine 181 and the steam turbine 190. In addition, as a use application of the high-temperature and high-pressure steam after cooling the product discharged from the second heat exchanger 131, the drive turbine 181 for driving the feed water pump 180 and the steam turbine 190 (the second and subsequent stages) The pressure and temperature conditions of the feed water heater, deaerator, small turbine, etc. are not limited to the above, and can be widely applied to steam utilization destinations.

  Further, the supercritical water gasification system is not limited to the above-described embodiment. For example, as shown in FIG. 2 in which the same reference numerals are given to the portions corresponding to FIG. 1, the second heat exchanger 131 (see FIG. 1) ), The steam after preheating the slurry discharged from the first heat exchanger 130 is lower than the temperature of the flow path 150 downstream of the first heat exchanger 130 and the pressure of the flow path 150 You may make it collect | recover to a lower part (for example, the deaerator 200). In addition, an outlet of the condensate pump 193, a feed water heater (not shown), or the like can be used as the collection point. Further, the recovery point may be switched depending on the temperature and pressure conditions in the flow path 150 downstream of the first heat exchanger 130.

  Examples of the nonmetallic catalyst used in the present embodiment include activated carbon, zeolite, and mixtures thereof. As the catalyst, a metal-based catalyst or an alkali catalyst can be used.

100 adjustment tank 110 crusher 120 supply pump 130 first heat exchanger (heat exchanger)
131 ... second heat exchanger 132 ... third heat exchanger 133 ... fourth heat exchanger 134 ... decompression device 140 ... drum type boiler (heating unit) 141 ... gasification reactor 142 ... reactor burner 143 ... water cooling wall 144 ... Superheater 145 ... Drum 150 ... Flow path 160 ... Flow control valve (flow control unit)
170 gas-liquid separator 171 gas tank 172 catalyst recovery unit 180 feedwater pump 181 drive turbine 190 steam turbine 191 generator 192 condenser 193 condensing pump

Claims (5)

A gasification reactor for supercritical water gasification of a slurry produced by preparing biomass, and a first heat exchange for preheating the slurry before supercritical water gasification in the gasification reactor A supercritical water gasification system comprising a device, wherein the slurry body is decomposed in a supercritical state to generate a fuel gas,
A heating unit having a drum-type boiler for discharging steam used for preheating the slurry body in the first heat exchanger,
Provided in a flow path connecting between the heating unit and the first heat exchanger, comprising a flow rate adjustment unit that controls the flow rate of the steam,
The supercritical water gasification system, wherein the flow rate adjustment unit controls a temperature of the slurry body at an outlet of the first heat exchanger by adjusting a flow rate of the steam. Further comprising a second heat exchanger different from the first heat exchanger,
The first heat exchanger cools a product of the gasification reactor using the steam whose temperature has been reduced by preheating the slurry body in the first heat exchanger. The supercritical water gasification system according to claim 1. The heating unit further includes a water supply pump for supplying water to the drum-type boiler, and a driving turbine for driving the water supply pump,
3. The supercritical water gasification system according to claim 2 , wherein the driving turbine is driven by using steam after cooling a product in the second heat exchanger. 4.   The said heating part is further provided with the circulation flow path which circulates water between the said drum type boiler and the water supply flow path to the said drum type boiler, The Claim 1 characterized by the above-mentioned. A supercritical water gasification system according to item 1.   The supercritical water gasification system according to any one of claims 1 to 4, wherein the drum-type boiler uses a product gas generated by the gasification process as a fuel.

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