CN108531233B

CN108531233B - Method for manufacturing biomass fuel

Info

Publication number: CN108531233B
Application number: CN201810293979.4A
Authority: CN
Inventors: 于洪江
Original assignee: Shanghai Jinni Environment Technology Co ltd
Current assignee: Shanghai Jinni Environment Technology Co ltd
Priority date: 2018-03-30
Filing date: 2018-03-30
Publication date: 2020-04-24
Anticipated expiration: 2038-03-30
Also published as: CN108531233A

Abstract

The invention relates to a method for manufacturing biomass fuel, which is used for producing the biomass fuel by liquefying biomass solids, and part of the fuel is used in a biomass solid liquefying process. In the invention, the viscosity of the original biomass solid is greatly reduced by heating the original biomass solid, so that the treatment pressure of the subsequent liquefaction process is reduced; the treatment pressure of the high-pressure process section is greatly reduced by completing partial or complete preheating in the low-pressure section; the pressure of a heat energy recovery system is reduced by adopting indirect heat energy recovery; by using the biomass boiler, part of the biomass fuel is used for providing energy for the process, and the cost of heat energy transmission and commercial purchase is reduced. The technology of metal interception, dry matter air drying and the like adopted in the process further improves the performance of the process.

Description

Method for manufacturing biomass fuel

Technical Field

The invention relates to an industrial processing method, in particular to a method for manufacturing biomass fuel.

Background

With the increasing exhaustion of fossil energy sources worldwide, renewable biomass energy sources are increasingly gaining attention. In the traditional biomass energy production, biomass is fermented to generate biogas with certain heat energy for utilization. The latest biomass energy production technology adopts a thermochemical method, namely, biomass solids are heated and pressurized to break cell structures in the biomass, the biomass is liquefied, and then the liquefied biomass is used for producing products similar to petroleum and coal.

The biomass solid is heated and pressurized, so that the cell structure in the biomass is broken, the form of the biomass is converted from the original solid into flowable liquid, and the method is one of the main steps of the current biomass fuel thermochemical method production. The technologies of biomass low-temperature carbonization, biomass gasification and the like all comprise the process. The main process of the process comprises the following steps: firstly, biomass which is shaped like a solid is changed into flowable liquid by methods of adding water and the like, then the flowable liquid is cut up and filtered to form materials suitable for continuous treatment, and then the materials are pressurized, preheated, heated, reacted and the like to crack cells in the biomass, so that water bound by biological cells is released, the biomass is changed into liquid from solid, and the liquid biomass can enter the manufacturing process of biomass fuel after being cooled and decompressed.

Compared with other biomass energy production processes, the biomass liquefaction process has great advantages. Firstly, because the pressure is applied during the heating, the whole process system does not evaporate, and most of the heat value in the biomass is reserved; in addition, energy in liquefied biomass is recovered to preheat the raw material, so that energy consumption in the process can be greatly saved. However, the above process has disadvantages that in order to increase the fluidity of the biomass, a large amount of water needs to be added to the biomass before treatment, and the total amount of the biomass is greatly increased, thereby greatly increasing the liquefaction cost of the biomass; in addition, after the materials enter the high-pressure pump, all subsequent process equipment is high-pressure, the manufacturing cost of the whole liquefaction equipment is greatly improved, and the operation and maintenance difficulty is correspondingly improved.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a method for manufacturing biomass fuel.

The purpose of the invention can be realized by the following technical scheme: a method for manufacturing biomass fuel is characterized by comprising the following steps:

s1, preheating the biomass solid material;

s2, feeding the preheated biomass solid material into a positive displacement pump, and feeding the biomass solid material into a low-pressure pump after chopping, filtering and dosing under the driving of the positive displacement pump, wherein the low-pressure pump inputs the material into a low-pressure preheater;

s3, heating the material to a first preheating temperature by a low-pressure preheater, then sending the material into a high-pressure pump, re-pressurizing the material by the high-pressure pump, then sending the material into a high-pressure preheater, heating the material to a second preheating temperature by the high-pressure preheater, and then sending the material into the high-pressure heater;

or the low-pressure preheater directly heats the material to a second preheating temperature and then sends the material into the high-pressure pump, the high-pressure pump re-pressurizes the material, and the material enters the high-pressure heater;

s4, heating the materials to the liquefaction temperature by the high-pressure heater, then feeding the materials into the reaction kettle, feeding the materials flowing out of the reaction kettle into a heat energy recoverer and a cooler in sequence, reducing the pressure, finally producing liquefied biomass, feeding the liquefied biomass into a subsequent biomass fuel preparation process, and providing heat energy for the step S3 by the produced partial fuel through a biomass boiler.

Further, the heating before the liquefaction of the biomass solid aims to greatly reduce the viscosity of the biomass solid. Before the biomass solid is liquefied, an independent heat source or a recovered heat source is used for heating;

the independent heat source is electricity, hot water or superheated steam;

the heat recovery source is heat energy recovered from liquefied high-temperature biomass, and the heat energy is recovered through a heat transfer medium in an indirect heat energy recoverer. After the heat energy is recovered, the temperature of the liquefied biomass is greatly reduced.

Furthermore, the heating equipment used when the independent heat source or the recycling heat source heats the biomass solid is provided with auxiliary equipment with a stirring function and a chopping function.

Further, the chopping is to cut off the larger particles or fibers contained in the biomass solid material;

the filtration is to filter the materials with particles larger than a limited size, and the limited size range is 1-2 mm; the aperture is small, the subsequent equipment is well protected, but the resistance is large, and the cleaning is frequent; the aperture is large, the protection to subsequent equipment is slightly poor, but the resistance is small, and the cleaning frequency is reduced. The size has advantages and disadvantages, and needs to be determined according to the type of biomass in practice.

The medicine that adds adopt charge device to receive and carry from charge equipment for medicine and biomass solid material intensive mixing still have in the charge device and adsorb and deposit the function, get rid of the harmful metal in the biomass solid material, prevent the damage of these harmful metal to equipment. The dosing equipment comprises a dosing tank, a medicament preparation device and a metering pump.

Further, the pressure selection of the low-pressure pump is determined according to the actual flow of the subsequent process, and when the temperature of the material preheated by the low-pressure preheater only reaches the first preheating temperature, the output pressure required by the low-pressure pump is lower; when the temperature of the material preheated by the low-pressure preheater reaches the second preheating temperature, the output pressure required by the low-pressure pump is higher.

Further, the low-pressure pump pumps the material into the tube side of the low-pressure preheater, and the heat energy of the low-pressure preheater comes from the recovered heat energy of the step S4.

Further, the first preheating temperature is 60-100 ℃. At this time, the required output pressure of the low-pressure pump is low; the second preheating temperature is 100-200 ℃, and at the moment, the output pressure required by the low-pressure pump is higher.

Further, when the temperature of the material preheated by the low-pressure preheater only reaches the first preheating temperature, the material output from the low-pressure preheater firstly enters a normal-pressure feeding tank and then enters a feeding hole of the high-pressure pump; when the temperature of the material preheated by the low-pressure preheater reaches the second preheating temperature, the material output from the low-pressure preheater firstly enters a pressure feeding tank and then enters the feeding hole of the high-pressure pump.

Further, the pressure in the pressure feeding tank can be dynamically adjusted, and the pressure in the tank is always greater than the saturated steam pressure of the water corresponding to the second preheating temperature.

Further, when the temperature of the material preheated by the low-pressure preheater only reaches the first preheating temperature, the material output by the high-pressure pump firstly enters the high-pressure preheater, the heat source of the high-pressure preheater is the recycling heat source in the step S4, and the material output by the high-pressure preheater enters the high-pressure heater;

when the temperature of the material preheated by the low-pressure preheater reaches the second preheating temperature, the output material of the high-pressure pump directly enters the high-pressure heater.

Further, the high-pressure heater heats the material by using an external heat source, the temperature of the biomass material is higher than or equal to the temperature required by biomass liquefaction after the biomass material is heated by the high-pressure heater, and the high-pressure heater indirectly heats the biomass material by a heating medium;

the external heat source used by the high-pressure heater is high-temperature heat conduction oil, high-temperature molten salt or high-temperature steam.

Further, the output pressure of the high-pressure pump meets the condition that the residual pressure of the materials when the materials reach the reaction kettle is larger than the saturated steam pressure of water corresponding to the liquefaction temperature of the biomass.

Further, the material output by the high-pressure heater in the step S4 stays in the reaction kettle for 10-25 minutes in a high-temperature and high-pressure state; each biomass liquefaction has its own corresponding optimum residence time, increasing residence time is not detrimental to biomass liquefaction except for the waste of some equipment and energy. If the laboratory test results are 5 minutes dwell, the industrial setting is usually 10 minutes, or slightly more; if the test results are 10 minutes, usually 15 minutes, or slightly more, are chosen.

The reaction kettle can be also provided with a heating device or not, and the condition is to ensure that the temperature of the materials is always higher than or equal to the temperature required by the liquefaction of the biomass when the materials stay in the reaction kettle.

Furthermore, a filtering and precipitating device is arranged in the reaction kettle, so that the metal is precipitated and filtered, and does not enter the subsequent process, thereby preventing the metal from damaging the subsequent process equipment.

Further, the biomass liquefied in the reaction kettle flows into a heat energy recoverer to recover heat in the liquefied biomass, the heat energy recoverer indirectly recovers heat energy through a heat medium, the heat medium after energy recovery flows into a shell pass of a high-pressure preheater and/or a shell pass of a low-pressure preheater and/or a preheating device before biomass solid liquefaction, and biomass solid materials in the biomass solid materials are indirectly heated.

Furthermore, the heat energy recoverer comprises main equipment such as a high-pressure heat exchanger, a medium pressurizing pump, a medium expander and the like;

the heat energy recoverer uses high-temperature resistant low-pressure heat transfer medium, such as heat transfer oil.

After the liquefied biomass is subjected to heat recovery by the heat energy recoverer, the liquefied biomass enters a cooler to further cool the liquefied biomass; if the energy in the liquefied biomass does not need to be recovered, the liquefied biomass in the reaction kettle directly flows into the cooler;

the cooler is a security cooler and comprises a high-pressure heat exchanger, a cooling medium booster pump, a medium cooling tower and other main devices.

Further, the liquefied biomass flowing out of the cooler enters a pressure reduction device for pressure reduction, and the biomass after pressure reduction is sent to the next biomass fuel preparation process;

the pressure reducing devices work continuously, a plurality of pressure reducing devices are arranged, all the pressure reducing devices are arranged in parallel, an automatic switching device is arranged in a parallel system, and one pressure reducing device in the parallel pressure reducing devices can work normally all the time through automatic detection and automatic control.

The liquefied biomass obtained in step S4 is subjected to a subsequent biomass fuel preparation process and utilized as follows: the method comprises the following steps of firstly enabling liquefied biomass to enter a liquid storage tank, feeding the liquefied biomass into a dehydrator for dehydration by using a positive displacement pump, then feeding the dehydrated biomass into an air dryer, and feeding dried biomass solids into a granulator for granulation. The heated heat conducting oil is used as a heat source of the high-pressure heater. The waste liquid removed during dewatering is treated using a Membrane Bioreactor (MBR). And a small amount of sludge generated by the MBR process is conveyed to the foremost end of the biomass liquefaction process and is uniformly treated after being mixed with biomass solids.

Furthermore, the liquid storage tank is a closed tank body, a stirring device is arranged in the liquid storage tank to prevent the liquefied biomass from settling, a gas collecting device is arranged at the upper part of the liquid storage tank, and gas overflowing from the liquefied biomass is conveyed to an air inlet hole of the biomass heat-conducting oil furnace through a blower after being collected, is mixed with natural air, enters the biomass heat-conducting oil furnace to assist in combustion and is discharged; the dehydrator can be any conventional dehydrating equipment, and is provided with flocculant preparation and adding equipment; the air dryer is internally provided with a stirring device which can uniformly distribute biomass solids in the whole air dryer, water in the air dryer can be blown out in the form of micro particle water mist by high-pressure wind power, the upper opening at the tail end of the air dryer is pumped out by an induced draft fan, the water mist pumped out by the induced draft fan enters the bottom of a filter tank, air in the air filter is filtered and discharged to the atmosphere by water in the filter tank, and fine particle impurities in the air filter are intercepted by the water in the filter tank and fall into the bottom of the filter tank to be periodically discharged. The water content of the dried biomass solid can be adjusted to meet the requirement of the biomass heat conduction oil boiler on the water content of the fuel. The size of the biomass solid after granulation can be adjusted to meet the requirement of the biomass boiler on the size of the fuel.

And a part of the granulated biomass solid is used as the fuel of the biomass heat conduction oil boiler to heat the heat conduction oil, the heated heat conduction oil is used as the heat source of the high-pressure heater, and the redundant biomass fuel can be used for other purposes. When the high-pressure heater has other heat sources for heating, the biomass fuel can be used as fuel of other industrial or domestic devices.

The waste gas generated in the whole process is subjected to deslagging and desulfurization and dust removal, and is discharged to the atmosphere through a chimney after reaching the discharge standard; the Membrane Bioreactor (MBR) can realize the processes of denitrification and removal of various pollutants such as BOD, COD and the like, the water quality treated by the MBR can directly reach the locally specified discharge standard, and the treated water can be directly discharged and can also be recycled. A small amount of excess sludge generated by the membrane bioreactor process is mixed with biomass solid incoming materials and then treated as biomass solids.

Compared with the prior art, the method greatly reduces the viscosity of the original biomass solid by heating the original biomass solid, thereby reducing the treatment pressure of the subsequent liquefaction process; the treatment pressure of the high-pressure process section is greatly reduced by completing partial or all pretreatment in the low-pressure section; the indirect heat energy recovery is adopted, so that the pressure of a heat energy recovery system is reduced; by using the biomass boiler, part of the biomass solids are utilized locally, so that the cost of heat energy transmission and commercial purchase is reduced; the performance of the process is further improved by adopting metal interception, dry matter air drying and the like in the process.

Drawings

FIG. 1 is an overall process flow diagram of a biomass fuel production method of the present invention.

FIG. 2 is a flow chart of the process of the embodiment of the invention, wherein the temperature of the material preheated by the low-pressure preheater reaches the first preheating temperature.

FIG. 3 is a flow chart of the process of the embodiment of the invention, wherein the temperature of the material preheated by the low-pressure preheater reaches the second preheating temperature.

FIG. 4 is a flow chart of a biomass fuel preparation process according to an embodiment of the present invention.

In the figure: 1. a bottom bin, 2, a viscous material delivery pump, 3, a high-level bin, 4, feeding equipment with a heating function, 5, positive displacement pumps A and 6, a chopper, 7, a filter, 8, a dosing tank, 9, medicament preparation and medicament delivery equipment, 10, a low-pressure pump A, 11, a low-pressure preheater, 12, a feeding tank, 13, a high-pressure pump, 14, a high-pressure preheater, 15, a high-pressure heater, 17, a reaction kettle, 18, a heat energy recoverer, 19, a heat-conducting oil pressure lifting pump, 20, an expansion tank A, 21, a safety cooler, 22, a busbar, 23, a pressure reducing valve A, 24, a pressure reducing valve B, 25, a pressure reducing valve C, 30, a safety cooling pump, 31, a high-level cooling tower, 41, a liquid storage tank, 42, a positive displacement pump B, 43, a dehydrator, 44, medicament dosing equipment, 45, a conveyor, 46, an air dryer, 47, a granulator, 48 and a biomass heat-conducting oil boiler, 49. an overflow gas delivery pump, 50, a heat transfer oil pump, 51, an expansion tank B, 52, a cyclone separator, 53, a desulfurization and dust removal device, 54, a chimney, 60, a dewatering liquid lifting pump, 61, a membrane bioreactor, 101, a biomass solid raw material delivery pipe, 102, a biomass solid raw material lifting pipe, 103, a heating device feed pipe, 104, a chopper feed pipe, 105, a filter feed pipe, 106, a dosing tank feed pipe, 107, a dosing tank output pipe, 108, a low-pressure preheater input pipe, 109, a low-pressure preheater output pipe, 110, a normal-pressure feed tank output pipe, 201, an input pipe, 202, a high-pressure heater input pipe, 203, a high-pressure heater output pipe, 204, a reaction vessel output pipe, 205, a heat energy recoverer output pipe, 206, a safety cooler output pipe, 301, a heat energy heat flow recoverer output pipe, 302, a high-pressure preheater heat flow output pipe, 303, a low, 304. heating equipment heat flow output pipe, 305, heat energy recoverer heat flow input pipe, 401, liquid storage tank input pipe, 402, liquid storage tank output pipe, 403, dehydrator input pipe, 404, dehydrator output pipe, 405, air dryer input pipe, 406, air dryer output pipe, 407, granulator output pipe, 409, gas collecting pipe, 410, collected gas input pipe, 411, dehydration conveying pipe, 501, high temperature heat medium input pipe, 502, low temperature heat medium output pipe, 601, membrane bioreactor input pipe, 602, qualified water discharge pipe, 701, and residual biomass fuel output.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. In the embodiment, the biomass solid is municipal sludge, the water content of the sludge is 80%, and the feeding temperature is 15 ℃.

Example 1

In this example, the temperature of the material preheated by the low-pressure preheater reaches the first preheating temperature, and the process flow is shown in fig. 2. The biomass solids reach a viscous material conveying pump 2 from a bottom bunker 1 through a biomass solid raw material conveying pipe 101, are lifted to a high-level bunker 3 through a biomass solid fuel lifting pipe 102, and are conveyed to a feeding device 4 with a heating function from the high-level bunker 3 through a screw conveyor (not shown in the figure) and a heating device feeding pipe 103. In this example, the heating heat source used by the feeding device 4 with the heating function is a recovery heat source, and the heating mode is indirect heating. The biomass material reaches 40 ℃ after being preheated in the feeding equipment 4 with the heating function and flows into the positive displacement pump 5. The positive displacement pump 5 pressurizes the biomass material, conveys the biomass material to the chopper 6 through the chopper feeding pipe 104, conveys the biomass material to the filter 7 through the filter feeding pipe 105, conveys the biomass material to the dosing tank 8 through the dosing

tank feeding pipe

106, 9 is medicament preparation and medicament conveying equipment, and the added medicament is a scale inhibitor, so that scaling in a heat exchanger pipeline during subsequent heating of the material is prevented. The dosed materials enter the low-pressure pump 10 through a dosing tank output pipe 107. The low pressure pump 10 pressurizes the material and feeds it to the low pressure preheater 11 through the low pressure preheater input 108. After the material is preheated by the low-pressure preheater 11 to reach the first preheating temperature of 80 ℃, the material enters the feeding tank 12 through the output pipe 109 of the low-pressure preheater, the feeding tank 12 is a normal-pressure feeding tank, and the material in the feeding tank 12 enters the high-pressure pump 13 through the output pipe 110 of the feeding tank.

The high pressure pump 13 pressurizes the material and feeds it through inlet 201 to the high pressure preheater 14, which high pressure preheater 14 uses a recovered heat source. The material reaches 160 ℃ in the high-pressure preheater and enters the high-pressure heater 15 through the high-pressure heater inlet pipe 202. The high temperature heat medium flows into the high temperature side of the high pressure heater 15 through the high temperature heat medium input pipe 501, and the low temperature heat medium flows out from the low temperature side of the high pressure heater 15 and returns through the low temperature heat medium output pipe 502. The heated material enters the reaction kettle 17 through the output pipe 203 of the high-pressure heater after reaching the liquefaction temperature of the biomass of 250 ℃. The liquefied biomass enters the heat energy recoverer 18 from the reaction kettle 17 through the reaction kettle output pipe 204, the temperature of the liquefied biomass after heat energy recovery is reduced to 100 ℃, and the liquefied biomass enters the safety cooler 21 through the heat energy recoverer output pipe 205 to be further cooled to 40 ℃. The safety cooler 21 is an indirect cooler, the cooling medium is pumped from the safety cooling pump 30 to the low temperature side of the safety cooler 21, the cooling medium at the high temperature side of the safety cooler 21 flows into the high-level cooling tower 31, and the cooled medium is recycled into the safety cooling pump 21. The cooled liquefied biomass enters the manifold 22 through the safety cooler output pipe 206. The pressure reducing valves a 23, B24 and C25 are connected to the bus 22, and when the system is in operation, one pressure reducing valve is always open, and the remaining pressure reducing valves are closed. When one working pressure reducing valve is blocked, the other pressure reducing valve is automatically opened. In this embodiment there are 3 pressure reducing valves installed in parallel. The outlet of the pressure reducing valve is connected to a reservoir inlet pipe 401, and the liquefied biomass is transported to the subsequent biomass fuel preparation process through the pipe 401.

The heat energy recoverer 18 indirectly recovers heat energy of the high-temperature liquefied biomass through heat transfer oil. The heated heat conduction oil is introduced into a heat energy recoverer heat flow output pipe 301 from the high-temperature side of the heat energy recoverer 18, then enters the high-temperature side of the high-pressure preheater 14, then enters the high-temperature side of the low-pressure preheater 11 from the low-temperature side of the high-pressure preheater 14 through a high-pressure preheater heat flow output pipe 302, then enters the high-temperature side of the warming equipment 4 from the low-temperature side of the low-pressure preheater 11 through a low-pressure preheater heat flow output pipe 303, the low-temperature side of the warming equipment 4 returns to the input end of a heat conduction oil pressure lifting pump 19 through a warming equipment heat flow output pipe 304, after the heat conduction oil pressure is lifted by the heat conduction oil pressure lifting pump 19, the. An expansion tank A20 is arranged on the heat flow output pipe 301 of the heat energy recoverer.

Example 2

In this example, the temperature of the material preheated by the low-pressure preheater reaches the second preheating temperature, the process flow is shown in fig. 3, the biomass solid is municipal sludge, the water content of the feed sludge is 80%, and the feed temperature is 15 ℃. As shown in fig. 1, the biomass solids are conveyed from the bottom bunker 1 through the biomass solid raw material conveying pipe 101 to the viscous material conveying pump 2, then lifted to the high bunker 3 through the biomass solid fuel riser pipe 102, and then conveyed from the high bunker 3 to the feeding device 4 with a heating function through the screw conveyor (not shown in the figure) and the feeding pipe 103 of the heating device. In this example, the heating heat source used by the feeding device with the heating function is a recycling heat source, and the heating mode is indirect heating. The biomass material reaches 40 ℃ after being preheated in the feeding equipment 4 with the heating function and flows into the positive displacement pump 5. The positive displacement pump 5 pressurizes the biomass material, conveys the biomass material to the chopper 6 through the chopper feeding pipe 104, conveys the biomass material to the filter 7 through the filter feeding pipe 105, conveys the biomass material to the dosing tank 8 through the dosing

tank feeding pipe

106, 9 is medicament preparation and medicament conveying equipment, and the added medicament is a scale inhibitor, so that scaling in a heat exchanger pipeline during subsequent heating of the material is prevented. The dosed materials enter the low-pressure pump 10 through a dosing tank output pipe 107. The low pressure pump 10 pressurizes the material and feeds it to the low pressure preheater 11 through the low pressure preheater input 108. After the material is preheated by the low-pressure preheater 11 to reach the second preheating temperature of 160 ℃, the material enters the feeding tank 12 through the output pipe 109 of the low-pressure preheater, the feeding tank 12 is a pressure feeding tank, and the pressure in the pressure feeding tank can be adjusted.

The material in the feed tank 12 enters the high pressure pump 13, and the pressurized material enters the high pressure heater 15 through the input pipe 201. The high temperature heat medium flows into the high temperature side of the high pressure heater 15 through the high temperature heat medium input pipe 501, and the low temperature heat medium flows out from the low temperature side of the high pressure heater 15 and returns through the low temperature heat medium output pipe 502. The heated material enters the reaction kettle 17 through the output pipe 203 of the high-pressure heater after reaching the liquefaction temperature of the biomass of 250 ℃. The liquefied biomass enters the heat energy recoverer 18 from the reaction kettle 17 through the reaction kettle output pipe 204, the temperature of the liquefied biomass after heat energy recovery is reduced to 100 ℃, and the liquefied biomass enters the safety cooler 21 through the heat energy recoverer output pipe 205 to be further cooled to 40 ℃. The safety cooler 21 is an indirect cooler, the cooling medium is pumped from the safety cooling pump 30 to the low temperature side of the safety cooler 21, the cooling medium at the high temperature side of the safety cooler 21 flows into the high-level cooling tower 31, and the cooled medium is recycled into the safety cooling pump 21. The cooled liquefied biomass enters the manifold 22 through the safety cooler output pipe 206. Pressure relief valve a 23, pressure relief valve B24 and pressure relief valve C25 are connected to bus 22, and when the system is in operation, one pressure relief valve is always open, and the remaining pressure relief valves are closed. When one working pressure reducing valve is blocked, the other pressure reducing valve is automatically opened. In this example, 3 pressure reducing valves are installed in parallel. The outlet of the pressure reducing valve is connected to a reservoir inlet pipe 401, and the liquefied biomass is transported to the subsequent biomass fuel preparation process through the pipe 401.

Example 3

Biomass fuel preparation and use.

Biomass fuel preparation and use the liquefied biomass that has been cooled enters the tank 41 through the tank inlet pipe 401 as shown in fig. 4. A low speed agitator is installed in the reservoir to prevent settling of solids in the liquefied biomass. The liquefied biomass in the liquid storage tank enters the positive displacement pump B42 through the liquid storage tank output pipe 402, and the positive displacement pump B pumps the liquefied biomass into the dehydrator 43 through the dehydrator input pipe 403. The agent adding device 44 adds a flocculating agent to the liquefied biomass in the input pipe 403 of the dehydrator before the liquefied biomass enters the dehydrator 43, so as to obtain the biomass solid fuel, the water content of the dehydrated biomass solid fuel is 40%, the biomass solid fuel enters the conveyer 45 through the output pipe 404 of the dehydrator, the conveyer 45 sends the biomass solid fuel to the air dryer 46 through the output pipe 405 of the air dryer, and the water content of the air-dried biomass solid fuel is below 20%. The air-dried biomass solid fuel is sent to the granulator 47 through an air dryer output pipe 406. The biomass solid fuel after granulation is finished product biomass fuel, part of the biomass fuel is sent into the biomass heat conduction oil boiler 48 through the output pipe 407 of the granulator to be combusted, the heat conduction oil is heated, the rest biomass fuel is output through the pipeline 701 and used as other biomass fuel, the heat conduction oil heated to 270 ℃ enters the heat conduction oil pump 50, the heat conduction oil pump 50 conveys the heat conduction oil to the high-pressure heater 15 through the output pipe 501 of the heat conduction oil pump, the biomass solid is liquefied and heated, and the expansion groove B51 is installed on the upper portion of the pipeline 501. The circulated heat transfer oil returns to the biomass heat transfer oil furnace 48 through a pipeline 502.

The water treatment process in the process flow is shown in figure 4, the liquid COD5 removed during dehydration is 18000mg/L, BOD is 8000mg/L, and total nitrogen is 1400mg/L, and the liquid is sent to the dehydration liquid lift pump 60 through the removed water conveying pipe 411, and the dehydration liquid is lifted to the membrane bioreactor 61 for treatment by the lift pump 60 through the membrane bioreactor input pipe 601. The COD of the water treated by the MBR process is 60mg/L, the BOD5 is 1mg/L, the total nitrogen is 5mg/L, the water is discharged from the qualified water discharge pipe 602, the discharged liquid can be directly discharged or reused, and the sludge generated by the MBR process is conveyed to the bottom storage bin 1 through a pipeline and is mixed with incoming biomass solids for treatment.

The process of treating the overflowed gas in the process flow is shown in fig. 4, the overflowed gas at the upper part of the liquid storage tank is pumped out by an exhaust fan through a gas collecting pipeline 409, is conveyed to an air inlet of the biomass heat conduction oil boiler 48 through a collected gas input pipe 410, and is mixed with the atmosphere to be used as an oxygen source of the biomass heat conduction oil boiler 48. The gas discharged from the biomass heat conduction oil boiler 48 enters a cyclone separator 52 in the process of removing dust particles in the gas, the gas discharged from the cyclone separator 52 enters a desulfurization and dust removal device 53 so as to remove sulfide and fine dust in the gas, and the gas discharged from the desulfurization and dust removal device 53 is discharged from a chimney 54.

Claims

1. A method for manufacturing biomass fuel is characterized by comprising the following steps:

s1, preheating the biomass solid material;

the first preheating temperature is 60-100 ℃; the second preheating temperature is 100-200 ℃;

when the temperature of the material preheated by the low-pressure preheater only reaches a first preheating temperature, the material output from the low-pressure preheater firstly enters a normal-pressure feeding tank and then enters a feeding hole of a high-pressure pump;

s4, heating the materials to the liquefaction temperature by the high-pressure heater, then feeding the materials into the reaction kettle, feeding the materials flowing out of the reaction kettle into a heat energy recoverer and a cooler in sequence, reducing the pressure, finally producing liquefied biomass, feeding the liquefied biomass into a subsequent biomass fuel preparation process, and providing heat energy for the step S3 by the produced partial biomass fuel through a biomass boiler.

2. The method for manufacturing the biomass fuel as claimed in claim 1, wherein the biomass solid material is preheated by using an independent heat source or a recycling heat source;

the independent heat source is electricity, hot water or superheated steam;

the heat recovery source is heat energy recovered from liquefied high-temperature biomass, and the heat energy is recovered through a heat transfer medium in an indirect heat energy recoverer.

3. The method for manufacturing the biomass fuel according to claim 2, wherein the heating device used when the independent heat source or the recycling heat source heats the biomass solids is provided with an auxiliary device with stirring function and chopping function.

4. The method of claim 1, wherein the chopping is cutting larger particles or fibers contained in the biomass solid material;

the filtration is to filter the materials with particles larger than a defined size, and the defined size is 1 mm;

the dosing device is used for receiving the medicament conveyed from the dosing equipment, so that the medicament and the biomass solid material are fully mixed, meanwhile, the dosing device also has adsorption and precipitation functions, harmful metals in the biomass solid material are removed, and the dosing equipment comprises a dosing tank, a medicament preparation device and a metering pump.

5. The method of claim 1, wherein the low pressure pump pumps the material into the tube side of the low pressure preheater, and the heat energy of the low pressure preheater is recovered from the recovered heat energy of step S4.

6. The method for manufacturing the biomass fuel according to claim 1, wherein when the temperature of the material preheated by the low-pressure preheater only reaches the first preheating temperature, the material output by the high-pressure pump firstly enters the high-pressure preheater, the heat source of the high-pressure preheater is the recycling heat source in step S4, and the material output by the high-pressure preheater enters the high-pressure heater;

7. The method for manufacturing the biomass fuel according to claim 1, wherein the high-pressure heater heats the material by using an external heat source, the temperature of the biomass material is higher than or equal to the temperature required by biomass liquefaction after the biomass material is heated by the high-pressure heater, and the high-pressure heater indirectly heats the biomass material by a heating medium;

8. The method for manufacturing the biomass fuel according to claim 1, wherein the output pressure of the high-pressure pump is such that the residual pressure of the material reaching the reaction kettle is greater than the saturated vapor pressure of water corresponding to the liquefaction temperature of the biomass.

9. The method for manufacturing the biomass fuel according to claim 1, wherein the material output by the high-pressure heater in the step S4 stays in the reaction kettle under the high-temperature and high-pressure state for 10-25 minutes;

the reaction kettle is internally provided with a heating device, so that the temperature of the materials staying in the reaction kettle is always greater than or equal to the temperature required by the liquefaction of the biomass;

and a filtering and precipitating device is arranged in the reaction kettle, so that the metal is precipitated and filtered.

10. The method for manufacturing the biomass fuel according to claim 1, wherein the biomass liquefied in the reaction kettle flows into a thermal energy recoverer to recover heat in the liquefied biomass, the thermal energy recoverer indirectly recovers thermal energy through a thermal medium, the thermal medium after energy recovery flows into or on the shell side of the high-pressure preheater and/or on the shell side of the low-pressure preheater and/or on a preheating device before biomass solid liquefaction, and biomass solid materials in the biomass solid materials are indirectly heated.

11. The method for manufacturing the biomass fuel according to claim 1 or 10, wherein the thermal energy recoverer comprises a high-pressure heat exchanger, a medium pressurizing pump and a medium expander;

the heat energy recoverer uses a high-temperature resistant low-pressure heat transfer medium.

12. The method for manufacturing the biomass fuel according to claim 1 or 10, wherein the liquefied biomass enters a cooler to further cool the liquefied biomass after heat recovery through a thermal energy recoverer; if the energy in the liquefied biomass does not need to be recovered, the liquefied biomass in the reaction kettle directly flows into the cooler;

the cooler is a safety cooler and comprises a high-pressure heat exchanger, a cooling medium booster pump and a medium cooling tower.

13. The method for manufacturing the biomass fuel according to claim 1, wherein the liquefied biomass flowing out of the cooler enters a pressure reduction device for pressure reduction, and the biomass after pressure reduction is sent to the next biomass fuel preparation process;

14. The method for manufacturing biomass fuel according to claim 1, wherein the liquefied biomass obtained in step S4 enters a subsequent biomass fuel preparation process and utilizes the following steps: the method comprises the following steps of firstly enabling liquefied biomass to enter a liquid storage tank, using a positive displacement pump to convey the liquefied biomass into a dehydrator for dehydration, then conveying the dehydrated biomass into an air dryer for air drying, then conveying the dehydrated biomass into a granulator for granulation to prepare biomass fuel, heating part of the biomass fuel serving as fuel of a biomass heat conduction oil boiler for heat conduction oil, using the heated heat conduction oil as a heat source of a high-pressure heater, treating liquid removed during dehydration by using a membrane bioreactor, conveying sludge generated by the membrane bioreactor treatment process to the foremost end of the biomass liquefaction process, and uniformly treating the sludge after mixing with biomass solid materials.

15. The method for manufacturing a biomass fuel according to claim 14, wherein the liquid storage tank is a closed tank body, a stirring device is installed inside the liquid storage tank to prevent the liquefied biomass from settling, a gas collecting device is installed at the upper part of the liquid storage tank, and the gas overflowing from the liquefied biomass is collected, conveyed to the air inlet of the biomass heat-conducting oil furnace through an overflow gas conveying pump, mixed with natural air, enters the biomass heat-conducting oil furnace to assist combustion, and is discharged;

the dehydrator is provided with flocculant preparation and adding equipment, liquid removed during dehydration is treated by using a membrane bioreactor, the membrane bioreactor has the functions of denitrification and BOD and COD removal, the water quality treated by the membrane bioreactor directly reaches the locally specified discharge standard, and the treated water is directly discharged or recycled;

the air dryer is internally provided with a stirring device to uniformly distribute biomass solids in the whole air dryer, water in the air dryer is blown out in the form of micro-particle water mist by high-pressure wind power, the water mist pumped out by the draught fan is pumped out from the upper opening at the tail end of the air dryer, the water mist pumped out by the draught fan enters the bottom of a filter tank, air in the air dryer is filtered by water in the filter tank and discharged to the atmosphere, fine particle impurities in the air dryer are intercepted by the water in the filter tank and fall into the bottom of the filter tank, the air dryer is periodically discharged and cleaned, the water content of the air-dried biomass solids is adjusted to meet the requirement of the biomass heat conduction oil boiler on the water content of fuel, the air-dried biomass solids are sent into a granulator, and the size of the granulated biomass solids is;

and when the high-pressure heater is heated by other heat sources, the biomass fuel is completely used as the fuel of other industrial or civil devices, and gas discharged by the biomass heat conduction oil boiler is subjected to deslagging, desulfurization and dust removal, and is discharged to the atmosphere through a chimney after reaching the discharge standard.