CN-121991711-A - Three-cavity cooperative microwave pyrolysis equipment based on waste heat recovery and working method thereof

CN121991711ACN 121991711 ACN121991711 ACN 121991711ACN-121991711-A

Abstract

The invention provides three-cavity collaborative microwave pyrolysis equipment based on waste heat recovery and a working method thereof, which belong to the technical field of microwave heating, wherein a drying cavity, a pyrolysis cavity and a cooling cavity which are vertically distributed are adopted, the cavities are communicated through a cylinder-driven opposite opening and closing plate to form a gravity-driven vertical flow channel, and a PLC and a touch display module realize dynamic balance of material flow and energy flow according to temperature data fed back by thermocouples in the cavities. The device is integrated with a waste heat recovery module, the biogas generated by pyrolysis is introduced into a drying cavity heat exchange tube bundle through a circulating gas circuit tube group for indirect heat exchange, then the biogas is returned to a circulating water cooling box for further cooling, and finally the biogas enters a gas washing drying filter vat for gas washing, dehydration and multi-stage filtration, so that the standard emission of pyrolysis gas is ensured. According to the invention, through three-cavity cooperation and efficient recovery of waste heat, the material treatment efficiency and the energy utilization efficiency are improved, and the overall energy consumption of the system is reduced.

Inventors

LI HUA
TANG WENHAO
LI CHAO
WANG JUFEI
ZHANG YIYUN
XU RUI
Samuel Mbugua Niambra

Assignees

南京农业大学

Dates

Publication Date: 20260508
Application Date: 20260408

Claims (9)

1. The three-cavity collaborative microwave pyrolysis equipment based on waste heat recovery is characterized by comprising a mounting frame, a drying cavity (2), a pyrolysis cavity (4) and a cooling cavity (5) which are arranged on the mounting frame from top to bottom, wherein a waste heat recovery module (8) is further arranged on one side of the cooling cavity (5), a PLC and a touch display module (3) are further arranged on the mounting frame, the PLC and the touch display module (3) are electrically connected with K-type thermocouples in each cavity, and the three-cavity collaborative microwave pyrolysis equipment further comprises a gas washing drying filter vat (7) and a high-pressure self-priming pump (9); The drying cavity (2) comprises a drying cavity shell (202) and a drying cavity sealing door (201) arranged on the drying cavity shell (202), a drying cavity pair opening and closing plate (206) which is controlled to open and close by a drying cavity cylinder (203) is arranged in a channel between the bottom of the drying cavity (2) and the top of the pyrolysis cavity (4), the drying cavity cylinder (203) is controlled by a PLC and a touch display module (3) to reciprocate, a plurality of electric heating tubes (204) are arranged in parallel in the drying cavity (2), a heat exchange tube bundle (205) is further arranged in the drying cavity (2), and a water vapor outlet is formed in the side wall of the drying cavity (2).
2. The three-cavity collaborative microwave pyrolysis device based on waste heat recovery according to claim 1 is characterized in that the pyrolysis cavity (4) comprises a pyrolysis cavity shell (402) and a pyrolysis cavity sealing door (401) arranged on the pyrolysis cavity shell (402), a pyrolysis cavity opposite opening and closing plate (409) controlled to open and close by a pyrolysis cavity cylinder (403) is arranged in a channel between the bottom of the pyrolysis cavity (4) and the top of the cooling cavity (5), the pyrolysis cavity cylinder (403) is controlled by a PLC and a touch display module (3) to reciprocate, the cavity side wall of the pyrolysis cavity (4) is respectively connected with a plurality of magnetrons (405) through a plurality of rectangular waveguides (404), an air inlet cover (406) and a fan (407) are matched with the outer side of each magnetron (405), and a gas outlet is further arranged on the side wall of the pyrolysis cavity (4).
3. The three-cavity collaborative microwave pyrolysis equipment based on waste heat recovery according to claim 2, wherein the cooling cavity (5) comprises a cooling cavity shell (502) and a cooling cavity sealing door (501) arranged on the cooling cavity shell (502), a discharging guide rail (505) is arranged in the cooling cavity (5), a discharging drawer (504) is arranged on the discharging guide rail (505), a fixing bracket (507) is also arranged in the cooling cavity (5), and a cooling tube bundle (506) is arranged on the fixing bracket (507).
4. The three-cavity collaborative microwave pyrolysis equipment based on waste heat recovery according to claim 3, wherein the waste heat recovery module (8) comprises a circulating air channel conduit bracket (801), a circulating air channel pipe group (802) and a circulating water cooling tank (803), the circulating air channel pipe group (802) comprises a circulating air channel pipe group heating section (802 a), a circulating air channel pipe group oil outlet section (802 b) and a circulating air channel pipe group reflux condensing section (802 c), and the circulating air channel conduit bracket (801) is fixed in the circulating water cooling tank (803) and is used for supporting the part of the circulating air channel pipe group reflux condensing section (802 c) in the circulating water cooling tank (803).
5. The three-cavity collaborative microwave pyrolysis equipment based on waste heat recovery according to claim 4, wherein a gas outlet on the side wall of the pyrolysis cavity (4) is connected with an inlet of a heating section (802 a) of a circulating gas circuit pipe group, two outlets of the heating section (802 a) of the circulating gas circuit pipe group are respectively connected with an inlet of a heat exchange pipe bundle (205) and an inlet of an oil outlet section (802 b) of the circulating gas circuit pipe group, the outlets of the heat exchange pipe bundle (205) and a water vapor outlet on a drying cavity (2) are both connected with an inlet of a reflux condensing section (802 c) of the circulating gas circuit pipe group, the outlet of the reflux condensing section (802 c) of the circulating gas circuit pipe group is connected with an inlet of an external gas washing drying filter drum (7) after flowing through a circulating water cooling box (803), and the outlet of the oil outlet of the circulating gas circuit pipe group is vertically downwards connected to the air; the water inlet of the cooling tube bundle (506) is connected with the water outlet of the high-pressure self-priming pump (9), the water inlet of the high-pressure self-priming pump (9) is connected with the water outlet of the circulating water cooling box (803), and the water outlet of the cooling tube bundle (506) is connected with the water inlet of the circulating water cooling box (803) through the connecting tube (503).
6. The three-cavity collaborative microwave pyrolysis equipment based on waste heat recovery according to claim 2 is characterized in that the drying cavity cylinder (203) is connected with one end of a transmission rocker arm through a hinged pin shaft at the tail end of a push rod of the drying cavity cylinder (203), the other end of the transmission rocker arm is fixed on a rotation long shaft of a drying cavity opposite opening and closing plate (206), the drying cavity cylinder (203) is controlled by a PLC and a touch display module (3) to reciprocate, the drying cavity opposite opening and closing plate (206) is driven to open to two sides or close to the center along a preset track through the hinged pin shaft, and the control of the pyrolysis cavity opposite opening and closing plate (409) by the pyrolysis cavity cylinder (403) is the same as that of the drying cavity cylinder (203).
7. The three-cavity collaborative microwave pyrolysis equipment based on waste heat recovery according to claim 6 is characterized in that cut-off waveguides are additionally arranged at the positions of the drying cavity air cylinder (203) and the pyrolysis cavity air cylinder (403) where push rods penetrate through the shell, and high-temperature-resistant wire mesh sealing strips are arranged on contact surfaces of the drying cavity opposite opening and closing plate (206) and the pyrolysis cavity opposite opening and closing plate (409).
8. The three-cavity collaborative microwave pyrolysis device based on waste heat recovery according to claim 3 is characterized in that a metal plate and rock wool sandwich structure is adopted for the drying cavity sealing door (201) and the drying cavity shell (202), a high-wave-transmission refractory lining, a porous ceramic heat preservation layer and a metal shielding metal plate are sequentially arranged on the pyrolysis cavity sealing door (401) and the pyrolysis cavity shell (402) from inside to outside, and the cooling cavity sealing door (501) and the cooling cavity shell (502) are formed by the metal plate.
9. A method of operating a waste heat recovery based three-chamber collaborative microwave pyrolysis apparatus in accordance with claim 5, comprising the steps of: Placing the materials in a drying cavity (2), ensuring that the materials cover an electric heating tube (204), closing a sealing door (201) of the drying cavity, carrying out auxiliary heating dehydration on the materials by the electric heating tube (204) at the initial stage of equipment starting, enabling water vapor generated in the drying process to flow into a reflux condensing section (802C) of a circulating gas circuit tube group under negative pressure caused by a gas washing drying filter drum (7), then sequentially entering a circulating water cooling box (803) and the gas washing drying filter drum (7) for recycling, when a K-type thermocouple in the drying cavity detects that the temperature of the materials in the drying cavity (2) reaches 100-120 ℃ and is constant for a period of time, indicating that free moisture in the materials is basically removed, driving a drying cavity cylinder (203) to retract by a PLC and touch display module (3), opening a drying cavity opposite opening and closing plate (206), enabling the materials to fall into a pyrolysis cavity (4) by gravity, supporting by a supporting plate (408), controlling the drying cavity cylinder (203) to stretch out by the PLC and the touch display module (3), closing the opening and closing the opening plate (206), and placing the drying cavity into the drying cavity in the drying cavity (2), and operating in the same batch; The microwave source is turned on, the magnetron (405) converts electric energy into microwave energy, the microwave energy is uniformly fed into the pyrolysis cavity (4) from different phases through the rectangular waveguide (404), the microwave directly acts on material molecules to generate severe friction heat, the material is subjected to chemical bond breakage under an anaerobic environment to generate high-temperature pyrolysis oil, pyrolysis gas and biochar, the volatilized high-temperature macromolecule pyrolysis oil flows into a circulating gas circuit tube group heating section (802 a) from a gas outlet of the pyrolysis cavity (4), enters a circulating gas circuit tube group oil outlet section (802 b) under the action of gravity, is collected at an outlet of the circulating gas circuit tube group oil outlet section (802 b) after being cooled by air, flows into a circulating gas circuit tube group heating section (802 a) under negative pressure caused by a washing gas drying filter drum (7), then flows into a heat exchange tube bundle (205), the high-temperature gas is transferred into wet materials in the drying cavity (2) through a tube wall, the utilization of waste heat is finished, and the cooled gas enters a circulating water cooling tank (803) to be further condensed, and meanwhile, the high-temperature pyrolysis gas enters a circulating gas circuit reflux condensing section (803) to be cooled, and finally enters a circulating gas drying filter drum (803) to be discharged after reaching the standard, and the heat of the circulating gas is discharged from the circulating gas drying filter drum (803) and the residual heat is synchronously cooled; When the temperature of the materials detected by the K-type thermocouple in the pyrolysis cavity (4) reaches 600-900 ℃ and no gas is generated at the outlet of the gas washing and drying filter barrel (7), the pyrolysis is completed, the pyrolysis cavity cylinder (403) is controlled to retract through the PLC and the touch display module (3), the pyrolysis cavity opposite opening and closing plate (409) is opened, after the solid products naturally fall into the cooling cavity (5), the pyrolysis cavity cylinder (403) is driven to extend to close the pyrolysis cavity opposite opening and closing plate (409), then the drying cavity cylinder (203) is controlled to retract, the drying cavity opposite opening and closing plate (206) is opened, the next batch of materials fall into the pyrolysis cavity (4) from the drying cavity to be continuously pyrolyzed, the high-pressure self-priming pump (9) drives cooling water to circulate between the cooling tube bundle (506) and the circulating water cooling box (803), the heat of the solid products is taken away, and when the temperature of the K-type thermocouple in the cooling cavity (5) is below 100 ℃, the cooling cavity sealing door (501) is opened, the discharging drawer (504) is pulled out, and the biochar is taken out.

Description

Three-cavity cooperative microwave pyrolysis equipment based on waste heat recovery and working method thereof Technical Field The invention belongs to the technical field of microwave heating, and particularly relates to three-cavity collaborative microwave pyrolysis equipment based on waste heat recovery and a working method thereof. Background The problem of environmental pollution caused by global warming and fossil energy use is increasingly serious, and the pyrolysis technology is to convert biomass into pyrolysis oil, pyrolysis gas and biochar with high added value in an anaerobic or anoxic environment, so that the reduction and recycling of wastes are realized, and the pyrolysis technology is widely focused. Compared with the traditional pyrolysis process, the microwave pyrolysis directly applies microwave energy to internal molecules of biomass, so that internal particles are caused to move and generate heat, and the unique heating mechanism has the advantages of high heating speed, high instantaneous heating rate, selective heating and the like. However, the conventional batch microwave pyrolysis equipment needs to undergo frequent temperature rising and falling processes before and after each batch of reaction, so that a great deal of sensible heat of the wall surface and the heat insulation layer of the reactor is wasted, and the energy loss caused by the thermal inertia of the system is relatively high. The existing single-cavity structure is difficult to consider the early drying preheating and the later rapid cooling of materials, the continuous operation difficulty is high, and the pyrolysis production efficiency is reduced. In addition, sensible heat carried by the high-temperature gas generated by pyrolysis cannot be effectively recovered, so that the energy utilization efficiency of the system is low. Aiming at the problems, the invention provides three-cavity collaborative microwave pyrolysis equipment based on waste heat recovery. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides the three-cavity collaborative microwave pyrolysis equipment based on waste heat recovery and the working method thereof, continuous treatment under the gravity drive of materials is realized by constructing a collaborative framework integrating drying, pyrolysis and cooling, the treatment efficiency of the materials is improved, the sensible heat of pyrolysis gas is recycled to a drying stage by integrating a waste heat recovery module, the whole energy consumption of the system is effectively reduced, and in addition, the monitoring of the pyrolysis temperature of the materials and the control of collaborative work of each cavity are realized by designing a PLC and a touch display module, and the dynamic balance of material flow and energy flow is ensured. The present invention achieves the above technical object by the following technical means. The three-cavity collaborative microwave pyrolysis equipment based on waste heat recovery comprises a mounting frame, a drying cavity, a pyrolysis cavity and a cooling cavity which are arranged on the mounting frame from top to bottom, wherein a waste heat recovery module is further arranged on one side of the cooling cavity, a PLC and a touch display module are further arranged on the mounting frame and are electrically connected with K-type thermocouples in the cavities, and the three-cavity collaborative microwave pyrolysis equipment further comprises a gas washing drying filter barrel and a high-pressure self-priming pump. Further, the drying cavity comprises a drying cavity shell and a drying cavity sealing door arranged on the drying cavity shell, a drying cavity opposite opening and closing plate controlled by a drying cavity cylinder to open and close is arranged in a channel between the bottom of the drying cavity and the top of the pyrolysis cavity, the drying cavity cylinder is controlled by a PLC and a touch display module to reciprocate, a plurality of electric heating pipes are arranged in parallel in the drying cavity, a heat exchange pipe bundle is arranged in the drying cavity, and a water vapor outlet is arranged on the side wall of the drying cavity. The pyrolysis cavity comprises a pyrolysis cavity shell and a pyrolysis cavity sealing door arranged on the pyrolysis cavity shell, a pyrolysis cavity opposite opening and closing plate controlled to open and close by a pyrolysis cavity air cylinder is arranged in a channel between the bottom of the pyrolysis cavity and the top of the cooling cavity, the pyrolysis cavity air cylinder is controlled by a PLC and a touch display module to reciprocate, the side wall of a cavity of the pyrolysis cavity is respectively connected with a plurality of magnetrons through a plurality of rectangular waveguides, an air inlet cover and a fan are matched with the outer side of each magnetron, and a gas outlet is further formed in the side wall of the pyrolysis cavity. Fur