A biomass waste air pressure baking system and its use method

Abstract

The present invention belongs to the field of biomass baking technology, and specifically relates to a biomass waste gas pressure baking system and a method for using the same. The biomass waste gas pressure baking system of the present invention comprises a baking reactor and a heat supply and pressure system, wherein the heat supply and pressure system comprises a flue gas heat exchanger (1), a back pressure valve (5), a burner (6), a flue gas diverter (7) and a flue gas booster pump (8); the flue gas heat exchanger (1) is arranged on the outer wall of the baking reactor, and the inlet of the burner (6) is connected to the baking reactor. The present invention utilizes pressurized flue gas to promote the deoxidation and quality improvement of biomass at a lower temperature. The circulating flue gas can provide heat for baking and undergo a secondary reaction with the biomass to further deoxidize the biomass. On the one hand, it can enhance the heat exchange between the flue gas and the biomass, and on the other hand, it can promote the secondary reaction of the two, so that the biomass is further deoxidized and improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomass baking, and in particular relates to a biomass waste air pressure baking system and a use method thereof. Background Art

[0002] The inherent defects of biomass waste itself seriously limit its resource utilization. It has been proven that torrefaction pretreatment can improve the quality of biomass fuel. Torrefaction is a biomass thermochemical pretreatment technology, usually carried out at a relatively low temperature of 200-300℃ and in an inert environment at normal pressure. Torrefaction is used to remove moisture and small molecular organic matter from biomass, thereby obtaining biomass fuel with low moisture content, high energy density, and greater grindability and hydrophobicity. However, due to the relatively mild torrefaction conditions, the oxygen content of the torrefied product is not much different from that of the original biomass, resulting in no significant increase in the calorific value of biomass before and after torrefaction. Therefore, it is necessary to improve the torrefaction technology to enhance the torrefaction effect.

[0003] Current technology has proposed some solutions for optimizing and improving baking technology. CN103370401A discloses a method and system for pressurized baking of lignin biomass. This method uses pressurized inert gas to enhance the heat exchange between the gas and the biomass to achieve the effect of enhanced baking. Patent No. CN103608438B discloses a countercurrent oxygen-enhanced baking method, which supplies oxygen-containing gas into the baking reactor and allows the baking gas to flow countercurrently through the baking reactor to enhance heat transfer and reduce energy loss. However, the above method only enhances heat exchange under the baking temperature limit and cannot significantly increase the calorific value of the baked product.

[0004] CN208308788U discloses a biomass torrefaction system heated by an organic heat carrier. Specifically, the system includes a torrefaction system, a carrier gas supply system for providing gas to the torrefaction system, an organic heat carrier heating system for heating the torrefaction device, a temperature control system for controlling the temperature of the torrefaction system, and an exhaust gas collection system connected to the torrefaction system. The organic heat carrier heating system includes an oil storage tank and an oil heater. The air inlet of the carrier gas supply system is connected to the cylinder through the carrier gas inlet. The air inlet of the exhaust gas collection system is connected to the exhaust gas outlet. This technical solution provides precise temperature control during the torrefaction process, recyclable heat carriers, and high thermal efficiency, but it consumes a lot of energy and leaves room for improvement.

[0005] In summary, the prior art still lacks a gas pressure baking system with low cost and high processing efficiency. Summary of the Invention

[0006] In response to the above-mentioned defects of the prior art, the present invention provides a biomass waste gas pressure baking system, which uses pressurized flue gas to promote the deoxygenation and quality improvement of biomass at a lower temperature, thereby improving the biomass processing efficiency, and directly uses the gas generated by biomass for combustion to provide energy, thereby improving the energy utilization efficiency. The detailed technical solution of the present invention is described as follows.

[0007] To achieve the above-mentioned objectives, according to one aspect of the present invention, a biomass waste gas pressure torrefaction system is provided, comprising a torrefaction reactor and a heat supply and pressurization system, wherein the heat supply and pressurization system comprises a flue gas heat exchanger, a back pressure valve, a burner, a flue gas diverter and a flue gas booster pump; the flue gas heat exchanger is arranged on the outer wall of the torrefaction reactor, the inlet of the burner is connected to the torrefaction reactor, the back pressure valve is located between the burner and the torrefaction reactor, the flue gas outlet of the burner is connected to the inlet of the flue gas diverter, the flue gas diverter is provided with a first outlet and a second outlet, the first outlet is connected to the flue gas heat exchanger, the second outlet is connected to the inlet of the flue gas booster pump, and the outlet of the flue gas booster pump is connected to the torrefaction reactor.

[0008] Preferably, the flue gas diverter is provided with a third outlet, and the third outlet is connected to the atmosphere.

[0009] Preferably, the torrefaction reactor is connected to a biomass bin, and an air lock device is provided between the torrefaction reactor and the biomass bin.

[0010] Preferably, a conveying screw is provided in the baking reactor.

[0011] Preferably, the flow direction of the flue gas in the baking reactor is opposite to the movement direction of the conveying screw.

[0012] Preferably, the baking reactor is provided with a material outlet, and a locking device is provided inside the material outlet.

[0013] Preferably, a control system is further included, which includes a gas concentration sensor, a temperature sensor, a pressure sensor and a controller. The gas concentration sensor, the temperature sensor and the pressure sensor are all arranged inside the baking reactor, and the gas concentration sensor, the temperature sensor and the pressure sensor are all electrically connected to the controller.

[0014] According to another aspect of the present invention, a method for using a baking system is provided, comprising the following steps:

[0015] (s1) transporting the biomass raw material from the biomass bin to the torrefaction reactor through an air lock device;

[0016] (s2) the biomass raw material is pyrolyzed in the torrefaction reactor to generate torrefied coke and volatile matter, the torrefied coke is transported to a material outlet by a conveying screw, a locking device of the material outlet is opened to discharge the torrefied coke, and the volatile matter enters a burner through a back pressure valve and burns to generate waste heat flue gas;

[0017] (s3) The waste heat flue gas enters the flue gas diverter for diversion, and the waste heat flue gas enters the flue gas heat exchanger through the first outlet to indirectly provide heat to the torrefaction reactor. The waste heat flue gas enters the flue gas booster pump through the second outlet to directly provide heat and pressure to the torrefaction reactor, and the waste heat flue gas is discharged through the third outlet.

[0018] Preferably, a gas concentration sensor (1), a temperature sensor (12) and a pressure sensor are provided in the torrefaction reactor, the gas concentration sensor feeds back a gas concentration signal to a controller, and the controller maintains the flammability of the exhaust gas from the torrefaction reactor by controlling the flue gas flow rate distributed by the flue gas splitter to the first outlet, the second outlet and the third outlet; the temperature sensor and the pressure sensor feed back temperature and pressure signals in the torrefaction reactor to the controller, and the controller controls the temperature and pressure of the torrefaction reactor by controlling the flue gas flow rate distributed by the flue gas splitter to the first outlet, the second outlet and the third outlet.

[0019] Preferably, the working pressure of the baking reactor is 1-50 bar, and the working temperature of the baking reactor is 100-500°C.

[0020] In general, the beneficial effects of the present invention are:

[0021] (1) The present invention utilizes pressurized flue gas to promote the deoxidation and upgrading of biomass at a relatively low temperature, thereby obtaining baked biomass with high fuel quality. The circulating flue gas can provide heat for baking and undergo a secondary reaction with the biomass to further deoxidize the biomass, while the pressure can increase the flue gas concentration. The combination of the two can, on the one hand, enhance the heat exchange between the flue gas and the biomass, and on the other hand, promote the secondary reaction between the two, thereby further deoxidizing and upgrading the biomass.

[0022] (2) The present invention directly utilizes the gas generated by biomass for combustion energy, which is not only energy-saving and environmentally friendly, but also promotes the removal of oxygen from biomass by utilizing pressurized flue gas, thereby obtaining roasted biomass with high fuel quality.

[0023] (3) The operating temperature of the present invention is relatively low, and the energy required in the process is provided by the combustion of volatile matter, without the need for external heat supply, so the system is economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the present invention.

[0025] In all the drawings, the same reference numerals are used to represent the same elements or structures, including: flue gas heat exchanger 1, gas concentration sensor 2, air lock device 3, biomass bin 4, back pressure valve 5, burner 6, flue gas diverter 7, flue gas booster pump 8, controller 9, material outlet 10, heat exchanger flue gas outlet 11, temperature sensor 12, pressure sensor 13, conveying screw 14. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0027] Example

[0028] A biomass waste gas pressure baking system, such as Figure 1 As shown, it includes a torrefaction reactor, a heat supply and pressure system and a control system. The torrefaction reactor is used to torrefy biomass, the heat supply and pressure system is used to provide heat and pressure to the torrefaction reactor, and the control system controls the operation of the entire system.

[0029] The heating and pressurizing system includes a flue gas heat exchanger 1, a back pressure valve 5, a burner 6, a flue gas diverter 7 and a flue gas booster pump 8; the flue gas heat exchanger 1 is arranged on the outer wall of the torrefaction reactor; the inlet of the burner 6 is connected to the torrefaction reactor, and the combustible torrefaction gas generated by the torrefaction reactor enters the burner 6 for combustion to generate waste heat flue gas, and the back pressure valve 5 is located between the burner 6 and the torrefaction reactor for maintaining the pressure of the torrefaction reactor; the flue gas outlet of the burner 6 is connected to the inlet of the flue gas diverter 7, and the flue gas diverter 7 is provided with a first outlet and a second outlet, the first outlet is connected to the flue gas heat exchanger 1 for indirect heating of the torrefaction reactor, and the second outlet is connected to the inlet of the flue gas booster pump 8, and the outlet of the flue gas booster pump 8 is connected to the torrefaction reactor for pressurizing the waste heat flue gas and passing it into the torrefaction reactor for direct heating of the torrefaction reactor.

[0030] As a preferred embodiment, the flue gas diverter 7 is provided with a third outlet, which is connected to the atmosphere for discharging gas.

[0031] As a preferred embodiment, the torrefaction reactor is connected to the biomass bin 4, and an air lock device 3 is provided between the torrefaction reactor and the biomass bin 4. The biomass enters the torrefaction reactor through the air lock device 3 to be torrefied, thereby producing torrefied biomass.

[0032] As a preferred embodiment, a conveying screw 14 is provided in the torrefaction reactor for conveying the biomass in the torrefaction reactor.

[0033] As a preferred embodiment, the flow direction of the flue gas in the torrefaction reactor is opposite to the movement direction of the conveying screw 14 .

[0034] As a preferred embodiment, the torrefaction reactor is provided with a material outlet 10, and a locking device is provided inside the material outlet 10. The torrefied biomass is discharged from the torrefaction reactor through the locking device.

[0035] As a preferred embodiment, the control system includes a gas concentration sensor 2, a temperature sensor 12, a pressure sensor 13 and a controller 9. The gas concentration sensor 2, the temperature sensor 12, and the pressure sensor 13 are all arranged inside the baking reactor, and the gas concentration sensor 2, the temperature sensor 12, and the pressure sensor 13 are all electrically connected to the controller 9.

[0036] The gas concentration sensor 2 is used to detect the concentration of combustible components in the torrefaction gas and transmit the signal to the controller 9; the temperature sensor 12 is used to detect the temperature inside the torrefaction reactor and transmit the signal to the controller 9; the pressure sensor 13 is used to detect the pressure inside the torrefaction reactor and transmit the signal to the controller 9; the controller 9 is used to control the diversion of the waste heat flue gas, control the temperature and pressure of the torrefaction reactor, and ensure the combustibility of the gas entering the burner.

[0037] The biomass waste gas pressure roasting system of the present invention is used to treat biomass, comprising the following steps:

[0038] (s1) transporting the biomass raw material from the biomass bin 4 to the torrefaction reactor through the air lock device 3;

[0039] (s2) The biomass feedstock is pyrolyzed in the torrefaction reactor to generate torrefied coke and volatile matter. The torrefied coke is conveyed to the material outlet 10 by a conveying screw. The locking device of the material outlet 10 is opened to discharge the torrefied coke. The volatile matter enters the burner 6 through the back pressure valve 5 and is burned to generate waste heat flue gas.

[0040] (s3) The waste heat flue gas enters the flue gas diverter 7 for diversion, and the waste heat flue gas enters the flue gas heat exchanger 1 through the first outlet to indirectly provide heat to the torrefaction reactor. The waste heat flue gas enters the flue gas booster pump 8 through the second outlet to directly provide heat and pressure to the torrefaction reactor, and the waste heat flue gas is discharged through the third outlet.

[0041] As a preferred embodiment, a gas concentration sensor 2, a temperature sensor 12 and a pressure sensor 13 are provided in the torrefaction reactor. The gas concentration sensor 2 feeds back a gas concentration signal to the controller 9. The controller 9 maintains the flammability of the exhaust gas from the torrefaction reactor by controlling the flue gas flow rate distributed by the flue gas diverter 7 to the first outlet, the second outlet and the third outlet. The temperature sensor 12 and the pressure sensor 13 feed back temperature and pressure signals in the torrefaction reactor to the controller 9. The controller 9 controls the temperature and pressure of the torrefaction reactor by controlling the flue gas flow rate distributed by the flue gas diverter 7 to the first outlet, the second outlet and the third outlet.

[0042] As a preferred embodiment, the working pressure of the baking reactor is 1-50 bar, and the working temperature of the baking reactor is 100-500°C.

[0043] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A biomass waste gas pressure baking system, characterized in that: The invention comprises a baking reactor and a heat supply and pressurization system, wherein the heat supply and pressurization system comprises a flue gas heat exchanger (1), a back pressure valve (5), a burner (6), a flue gas diverter (7) and a flue gas booster pump (8); the flue gas heat exchanger (1) is arranged on the outer wall of the baking reactor, the inlet of the burner (6) is connected to the baking reactor, and the back pressure valve (5) is located between the burner (6) and the baking reactor for maintaining the pressure of the baking reactor; the flue gas outlet of the burner (6) is connected to the inlet of the flue gas diverter (7), and the flue gas diverter (7) is provided with a first outlet and a second outlet, the first outlet is connected to the flue gas heat exchanger (1) for indirectly supplying heat to the baking reactor, the second outlet is connected to the inlet of the flue gas booster pump (8), and the outlet of the flue gas booster pump (8) is connected to the baking reactor; Used to pressurize the waste heat flue gas and pass it into the roasting reactor, so as to directly heat the roasting reactor; the flue gas diverter (7) is provided with a third outlet, and the third outlet is connected to the atmosphere; The combustible torrefaction gas generated by the torrefaction reactor enters the burner (6) for combustion; A gas concentration sensor (2), a temperature sensor (12) and a pressure sensor (13) are provided in the baking reactor. The gas concentration sensor (2) feeds back a gas concentration signal to a controller (9). The controller (9) controls the flue gas flow rate of the first outlet, the second outlet and the third outlet to maintain the combustibility of the exhaust gas from the baking reactor. The temperature sensor (12) and the pressure sensor (13) feed back temperature and pressure signals in the baking reactor to the controller (9). The controller (9) controls the flue gas flow rate of the first outlet, the second outlet and the third outlet to control the temperature and pressure of the baking reactor. A conveying screw (14) is provided in the baking reactor, and the flow direction of the flue gas in the baking reactor is opposite to the movement direction of the conveying screw (14); the working pressure of the baking reactor is 1-50 bar, and the working temperature of the baking reactor is 100-500°C.

2. The baking system according to claim 1, characterized in that The torrefaction reactor is connected to a biomass bin (4), and an air lock device (3) is provided between the torrefaction reactor and the biomass bin (4).

3. The baking system according to claim 1, characterized in that The baking reactor is provided with a material outlet (10), and a locking device is provided inside the material outlet (10).

4. The method for using the baking system according to any one of claims 1 to 3, characterized in that: The following steps are involved: (s1) transporting the biomass raw material from the biomass bin (4) to the torrefaction reactor through the air lock device (3); (s2) The biomass raw material is pyrolyzed in the torrefaction reactor to generate torrefied coke and volatile matter, the torrefied coke is transported to the material outlet (10) by a conveying screw, the locking device of the material outlet (10) is opened to discharge the torrefied coke, and the volatile matter enters the burner (6) through the back pressure valve (5) and is burned to generate waste heat flue gas; (s3) The waste heat flue gas enters the flue gas diverter (7) for diversion, and the waste heat flue gas enters the flue gas heat exchanger (1) through the first outlet to indirectly supply heat to the baking reactor, and the waste heat flue gas directly supplies heat and pressure to the baking reactor through the second outlet and the flue gas booster pump (8), and the waste heat flue gas is discharged through the third outlet.

5. The method for using the baking system according to claim 4, characterized in that: A gas concentration sensor (2), a temperature sensor (12) and a pressure sensor (13) are provided in the baking reactor. The gas concentration sensor (2) feeds back a gas concentration signal to a controller (9). The controller (9) maintains the flammability of the exhaust gas from the baking reactor by controlling the flue gas flow rate of the first outlet, the second outlet and the third outlet distributed by the flue gas diverter (7). The temperature sensor (12) and the pressure sensor (13) feed back temperature and pressure signals in the baking reactor to the controller (9). The controller (9) controls the temperature and pressure of the baking reactor by controlling the flue gas flow rate of the first outlet, the second outlet and the third outlet distributed by the flue gas diverter (7).

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