Preparation method and device of high-value combustible gas

Abstract

The invention provides a preparation method and device of high-value combustible gas. The preparation method of the high-value combustible gas comprises the following steps: carrying out heating dehydration and mild carbonization on straws by utilizing an electromagnetic induction heating device under a negative pressure condition to obtain primary carbon; performing extrusion forming on the primary carbon, performing pyrolysis in a microwave pyrolysis device, and releasing pyrolysis gas to obtain secondary carbon; the pyrolysis gas is guided into an electromagnetic induction heating device to be deeply cracked and converted into combustible gas; according to the preparation method of the high-value fuel gas, the electromagnetic induction heating technology and the microwave heating technology are combined, the preparation method specifically comprises three stages, in the first stage, after negative pressure electromagnetic induction heating is conducted, lightly carbonized straw is extruded into a rod shape, in the second stage, rod-shaped carbon is pyrolyzed through the microwave technology, and the high-value fuel gas is obtained. And finally, the generated pyrolysis gas is subjected to electromagnetic induction high-temperature deep cracking in the third stage, so that the heat value and cleanliness of the combustible gas are improved, meanwhile, tar generation is reduced, and the high-quality combustible gas is obtained on the basis of multi-stage fine control.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass energy, and particularly to a method and device for preparing high-value combustible gas. Background Art

[0002] With the continuous growth of the demand for renewable energy, the efficient conversion and comprehensive utilization of biomass resources have attracted increasing attention. As a common biomass raw material, straw is mostly processed by traditional pyrolysis or gasification processes using a single heating method (such as direct combustion furnace heating), which has problems such as low heating efficiency, large tar production, and low quality of combustible gas. Electromagnetic induction heating and microwave heating (microwave pyrolysis) each have their own advantages: the former can quickly convert electrical energy into heat energy and achieve efficient heat transfer under negative pressure conditions; the latter can heat the material internally simultaneously, with rapid temperature rise and a controllable process.

[0003] If the electromagnetic induction heating and microwave heating technologies can be combined, it is expected to prepare high-quality combustible gas; however, there is currently no solution for combining electromagnetic induction heating and microwave heating technologies to prepare high-quality combustible gas. Summary of the Invention

[0004] The present invention aims to provide a method and device for preparing high-value combustible gas. The method involves extruding the mildly carbonized straw into a rod shape after the first-stage negative-pressure electromagnetic induction heating, then pyrolyzing the rod-shaped carbon using microwave technology in the second stage, and finally performing electromagnetic induction high-temperature deep cracking on the generated pyrolysis gas in the third stage, thereby improving the calorific value and cleanliness of the combustible gas while reducing tar production.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for preparing high-value combustible gas, comprising the following steps:

[0007] S1. Under negative pressure conditions, use an electromagnetic induction heating device to heat and dehydrate the straw and mildly carbonize it to obtain primary carbon;

[0008] S2. After extruding the primary carbon into a formed shape, place it in a microwave pyrolysis device for pyrolysis to release pyrolysis gas and obtain secondary carbon;

[0009] S3. Introduce the pyrolysis gas into an electromagnetic induction heating device for deep cracking to convert it into combustible gas.

[0010] Preferably, use a magnetic induction heating device to heat the straw to 200 - 300 °C and maintain it for 10 - 50 minutes in a negative pressure environment of -0.005 MPa to -0.08 MPa to heat and dehydrate the straw and mildly carbonize it to obtain primary carbon;

[0011] Among them, the power of the magnetic induction heating device is 10 - 30 kW, the frequency is 40 - 100 kHz, and the current is 10 - 30 A.

[0012] Preferably, the primary carbon is extruded into a rod shape or a block shape with a diameter of 10 - 30 mm, placed in a microwave pyrolysis device, and pyrolyzed at 400 - 800 °C for 2 - 10 min to release volatile components and obtain secondary carbon.

[0013] Among them, the microwave power of the microwave pyrolysis device is 3 - 10 kW, and the microwave frequency is 2000 - 3000 MHz.

[0014] Preferably, the pyrolysis gas is introduced into an electromagnetic induction heating device and cracked at 600 - 800 °C for 5 - 20 min to be converted into combustible gas.

[0015] Preferably, it further includes cooling, dust removal, and / or deacidification treatment of the obtained combustible gas.

[0016] In a second aspect, the present invention further provides a preparation device for high-value combustible gas for implementing the above method, including:

[0017] A negative-pressure electromagnetic induction heating unit for heating and dehydrating straw under negative-pressure conditions and slightly carbonizing it to obtain primary carbon;

[0018] An extrusion molding unit for extruding and molding the primary carbon;

[0019] A microwave pyrolysis unit for microwave pyrolysis of the extruded primary carbon;

[0020] An electromagnetic induction deep cracking unit for deeply cracking the pyrolysis gas generated during the microwave pyrolysis process.

[0021] Preferably, the negative-pressure electromagnetic induction heating unit includes:

[0022] An electromagnetic induction heating chamber with a straw feed port at one end and a primary carbon discharge port at the other end;

[0023] A first electromagnetic induction coil arranged on the electromagnetic induction heating chamber;

[0024] A first electromagnetic induction control unit arranged on the electromagnetic induction heating chamber for controlling the operation of the first electromagnetic induction coil;

[0025] A negative-pressure pump located on the electromagnetic induction heating chamber for evacuating the electromagnetic induction heating chamber;

[0026] The extrusion molding unit has a primary carbon feed port and a molding discharge port, and the primary carbon feed port is communicated with the primary carbon discharge port;

[0027] The microwave pyrolysis unit includes:

[0028] A microwave pyrolysis chamber, which is provided with a pyrolysis feed inlet and a pyrolysis gas discharge outlet, and the pyrolysis feed inlet is communicated with the molding discharge outlet;

[0029] A microwave generator, which is arranged on the microwave pyrolysis chamber;

[0030] A microwave control unit, which is arranged on the microwave pyrolysis chamber and is used to control the operation of the microwave generator;

[0031] The electromagnetic induction deep pyrolysis unit includes:

[0032] An electromagnetic induction deep pyrolysis chamber, which is provided with a pyrolysis gas feed inlet, and the pyrolysis gas feed inlet is communicated with the pyrolysis gas discharge outlet;

[0033] A second electromagnetic induction coil, which is arranged on the electromagnetic induction deep pyrolysis chamber;

[0034] A second electromagnetic induction control unit, which is arranged on the electromagnetic induction deep pyrolysis chamber and is used to control the operation of the second electromagnetic induction coil.

[0035] Preferably, it further includes a gas treatment unit, and the gas treatment unit includes:

[0036] A gas purification system. One end of the electromagnetic induction deep pyrolysis chamber away from the pyrolysis gas feed inlet is provided with a combustible gas outlet, and the combustible gas outlet is communicated with the gas purification system for purifying the combustible gas;

[0037] A gas collection tank, which is communicated with the gas purification system.

[0038] Preferably, the electromagnetic induction deep pyrolysis unit further includes:

[0039] A condenser, whose feed end is communicated with the pyrolysis gas discharge outlet;

[0040] An oil storage tank, one end of which is communicated with the discharge end of the condenser and the other end is communicated with the pyrolysis gas feed inlet.

[0041] Preferably, the negative pressure electromagnetic induction heating unit further includes:

[0042] A spiral feed rod, which is located in the electromagnetic induction heating chamber;

[0043] A feed motor, which is arranged on the electromagnetic induction heating chamber, and the rotating shaft of the feed motor is connected with the spiral feed rod to drive the spiral feed rod to rotate;

[0044] A stirrer is further arranged in the microwave pyrolysis chamber;

[0045] A secondary carbon discharge outlet is further arranged on the microwave pyrolysis chamber.

[0046] The preparation method and device of high-value combustible gas of the present invention have the following beneficial effects compared with the prior art:

[0047] The preparation method of high-value combustible gas of the present invention combines electromagnetic induction heating and microwave heating technologies, specifically including three stages. After negative-pressure electromagnetic induction heating in the first stage, the mildly carbonized straw is extruded into a rod shape, and then in the second stage, the microwave technology is used to pyrolyze the rod-shaped carbon. Finally, in the third stage, the pyrolysis gas generated is subjected to electromagnetic induction high-temperature deep cracking, so as to improve the calorific value and cleanliness of the combustible gas, while reducing tar generation, and obtaining high-quality combustible gas on the basis of multi-stage refined control. Brief Description of the Drawings

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0049] Figure 1 It is the preparation device of high-value combustible gas of the present invention. Detailed Embodiments

[0050] The following will combine the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0051] In the description of the present invention, it should be understood that the relationships indicating orientations or positions such as "upper" are based on the orientations or positions shown in the drawings, or the orientations or positions in which the products of the invention are usually placed during use, or the orientations or positions commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0052] The description order of the following embodiments does not limit the preferred order of the embodiments. Additionally, in the description of this application, the term "including" means "including but not limited to". The various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, which applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0053] An embodiment of this application provides a method for preparing high-value combustible gas, including the following steps:

[0054] S1. Under negative pressure conditions, use an electromagnetic induction heating device to heat and dehydrate the straw and mildly carbonize it to obtain primary carbon.

[0055] S2. After extruding the primary carbon into a shape, place it in a microwave pyrolysis device for pyrolysis to release pyrolysis gas and obtain secondary carbon.

[0056] S3. Introduce the pyrolysis gas into the electromagnetic induction heating device for deep cracking to convert it into combustible gas.

[0057] The method for preparing high-value combustible gas of the present invention combines electromagnetic induction heating and microwave heating technologies. Specifically, it includes three stages. After negative pressure electromagnetic induction heating in the first stage, the mildly carbonized straw is extruded into a rod shape. Then, in the second stage, microwave technology is used to pyrolyze the rod-shaped carbon. Finally, in the third stage, the generated volatile matter is subjected to electromagnetic induction high-temperature deep cracking, thereby improving the calorific value and cleanliness of the combustible gas, while reducing tar generation, and obtaining high-quality combustible gas on the basis of multi-stage refined control.

[0058] Specifically, under negative pressure conditions, an electromagnetic induction heating device is used to heat and dehydrate straw. Due to the cooperation of the negative pressure environment, the efficiency of dehydration and volatilization of volatile components can be effectively improved; the slightly carbonized carbon (primary carbon) obtained above is extruded into a rod shape or other required shapes in an extrusion device to obtain a more uniform internal temperature distribution during subsequent microwave heating; the forming process can be optimized and adjusted according to parameters such as the length and density of the rod-shaped carbon; after the primary carbon is extruded and formed, it is transported to a microwave pyrolysis device. The microwave device uniformly heats the carbon material within a set temperature range (such as 400°C to 800°C), causing its internal temperature to rise rapidly and generating volatile components. In this process, secondary carbon and pyrolysis gases containing tar, condensable organic substances, etc. can be obtained; the pyrolysis gas is introduced into the electromagnetic induction heating device for deep cracking under higher temperature conditions (such as 600°C to 800°C), converting macromolecular tar or other organic components into small molecule combustible gases (CO, H 2 , CH 4 etc.); after cracking, the generated combustible gas is cooled, dust-removed, and subjected to necessary purification treatment, and can be used for gas power generation, industrial heating, or other gas-using systems.

[0059] The method for preparing high-value combustible gas of the present invention has the following advantages:

[0060] Segmented fine control: The straw treatment is divided into three main steps: electromagnetic induction dehydration and slight carbonization, microwave pyrolysis after extrusion into a rod, and electromagnetic induction deep cracking, which can perform optimal control according to the physical and chemical characteristics of different stages;

[0061] The forming process improves the pyrolysis effect: Extruding and forming the primary carbon before microwave heating is beneficial to the uniformity of heating in the microwave field, reducing local overheating or insufficiency;

[0062] Efficient heating mode: The combination of electromagnetic induction and microwave heating realizes rapid and uniform temperature rise, avoiding the problem of low efficiency of traditional external heating;

[0063] Negative pressure operation: The negative pressure environment in the first stage helps to quickly dehydrate and reduce the oxygen content, enhancing safety and reducing by-product generation;

[0064] High-quality combustible gas: The third-stage deep cracking greatly reduces the tar content, increases the proportion and calorific value of small molecule components in the combustible gas.

[0065] In some embodiments, the straw is heated to 200 - 300 °C by a magnetic induction heating device and maintained for 10 - 50 min in a negative pressure environment of -0.005 MPa to -0.08 MPa, so as to heat and dehydrate the straw and mildly carbonize it to obtain primary carbon. Among them, the power of the magnetic induction heating device is 10 - 30 kW, the frequency is 40 - 100 kHz, and the current is 10 - 30 A. Specifically, the crushed straw (particle size about 5 - 10 mm) is placed in a negative pressure environment of -0.005 MPa to -0.08 MPa, the electromagnetic induction coil is turned on, and it is heated to 200 - 300 °C. During this process, most of the moisture and some low-boiling organic components are removed, and the preliminarily carbonized carbon material (primary carbon) is obtained.

[0066] In some embodiments, the primary carbon is sent to an extruder and an appropriate pressure, such as 5 - 20 MPa, is applied to extrude it into a rod shape or a block shape. The diameter of the rod-shaped or block-shaped primary carbon can be in the range of 10 - 30 mm, and the length can be matched according to the size of the subsequent microwave device. This rod-shaped carbon is more likely to obtain uniform heating in the microwave field. The extruded primary carbon is placed in a microwave pyrolysis device and pyrolyzed at 400 - 800 °C for 2 - 10 min. Among them, the microwave power of the microwave pyrolysis device is 3 - 10 kW, and the microwave frequency is 2000 - 3000 MHz. Pyrolysis gas is released and secondary carbon is obtained. During the microwave pyrolysis process, the moisture and tar components inside the carbon quickly volatilize and are led out to the separation unit, forming secondary carbon and pyrolysis gas. The pyrolysis gas released in this stage contains tar droplets, light organic substances, etc., which need to be further cracked or purified in the third stage. Specifically, the pyrolysis gas contains condensable components (tar) and non-condensable components. The condensable components are collected by a condenser and then it is tar. The non-condensable components in the pyrolysis gas are introduced into the magnetic induction heating device for cracking to obtain combustible gas. In some embodiments, the pyrolysis gas is introduced into the magnetic induction heating device and cracked at 600 - 800 °C for 5 - 20 min to be converted into combustible gas. The pyrolysis gas and the possibly carried tar components are introduced into the magnetic induction heating device and cracked at a high temperature of 600 - 800 °C. At this high temperature, the macromolecular organic substances are further cracked to generate small-molecule combustible gas, and the main components include CO, H 2 、CH 4 etc. After the combustible gas is further purified by measures such as cooling, dust removal or acid removal, it meets the quality requirements for direct utilization.

[0067] In some embodiments, it further includes cooling, dust removal and / or acid removal treatment for the obtained combustible gas.

[0068] In some embodiments, the straw includes corn straw, wheat straw, rice straw, sorghum straw, etc.

[0069] Through three-stage process and combined with an extrusion molding step, the present invention can obtain combustible gas with high calorific value and low tar, and the calorific value can reach 15 - 25 MJ / Nm 3 or higher; compared with the traditional single-stage pyrolysis or direct gasification, the process of the present invention effectively improves the gas production efficiency and reduces the generation of tar by-products.

[0070] Specifically, the calorific value of combustible gas refers to the heat released when the combustible gas of unit volume (usually standard cubic meter, i.e., Nm 3 ) is completely burned.

[0071] Based on the same inventive concept, the present invention also provides a preparation device for high-value combustible gas for implementing the above method, including:

[0072] A negative-pressure electromagnetic induction heating unit for heating and dehydrating straw under negative pressure conditions and slightly carbonizing it to obtain primary carbon;

[0073] An extrusion molding unit for extruding and molding the primary carbon;

[0074] A microwave pyrolysis unit for microwave pyrolysis of the extruded primary carbon;

[0075] An electromagnetic induction deep cracking unit for deeply cracking the pyrolysis gas generated during the microwave pyrolysis process.

[0076] In some embodiments, the negative-pressure electromagnetic induction heating unit includes:

[0077] An electromagnetic induction heating chamber 1, with a straw feed port 11 at one end and a primary carbon discharge port 12 at the other end;

[0078] A first electromagnetic induction coil 13, which is arranged on the electromagnetic induction heating chamber 1;

[0079] A first electromagnetic induction control unit 14, which is arranged on the electromagnetic induction heating chamber 1 and used to control the operation of the first electromagnetic induction coil 13;

[0080] A negative-pressure pump 15, located on the electromagnetic induction heating chamber 1 and used to evacuate the electromagnetic induction heating chamber 1;

[0081] The extrusion molding unit 2 has a primary carbon feed port 21 and a molding discharge port 22, and the primary carbon feed port 21 is communicated with the primary carbon discharge port 12;

[0082] The microwave pyrolysis unit includes:

[0083] A microwave pyrolysis chamber 3, with a pyrolysis feed port 31 and a pyrolysis gas discharge port 32 thereon, and the pyrolysis feed port 31 is communicated with the molding discharge port 22;

[0084] A microwave generator 33, which is arranged on the microwave pyrolysis chamber 3;

[0085] A microwave control unit 37, which is arranged on the microwave pyrolysis chamber 3 and is used to control the operation of the microwave generator 33;

[0086] The electromagnetic induction deep cracking unit includes:

[0087] An electromagnetic induction deep cracking chamber 4, on which there is a pyrolysis gas inlet 41, and the pyrolysis gas inlet 41 is communicated with the pyrolysis gas outlet 32;

[0088] A second electromagnetic induction coil 42, which is arranged on the electromagnetic induction deep cracking chamber 4;

[0089] A second electromagnetic induction control unit 43, which is arranged on the electromagnetic induction deep cracking chamber 4 and is used to control the operation of the second electromagnetic induction coil 42.

[0090] In some embodiments, a gas treatment unit is further included, and the gas treatment unit includes:

[0091] A gas purification system 5. There is a combustible gas outlet 44 at one end of the electromagnetic induction deep cracking chamber away from the pyrolysis gas inlet, and the combustible gas outlet 44 is communicated with the gas purification system 5 for purifying the combustible gas;

[0092] A gas collection tank 6, which is communicated with the gas purification system 5.

[0093] In some embodiments, the electromagnetic induction deep cracking unit further includes:

[0094] A condenser 45, whose feed end is communicated with the pyrolysis gas outlet 32;

[0095] An oil storage tank 46, one end of which is communicated with the discharge end of the condenser and the other end is communicated with the pyrolysis gas inlet 41.

[0096] Specifically, the working principle of the preparation device for high-value combustible gas of the present invention is as follows: The straw raw material enters the electromagnetic induction heating chamber 1 through the straw feed inlet 11. The electromagnetic induction heating chamber 1 is evacuated by the negative pressure pump 15 to form a negative pressure environment inside the electromagnetic induction heating chamber 1. The first electromagnetic induction control unit 14 is used to control the operation of the first electromagnetic induction coil 13, so that the temperature inside the electromagnetic induction heating chamber 1 reaches the set temperature. Under negative pressure conditions, the straw is dehydrated and slightly carbonized by electromagnetic induction heating to obtain primary carbon. The primary carbon enters the extrusion molding unit 2 through the primary carbon discharge port 12 and the primary carbon feed inlet 21 for extrusion molding. The extruded primary carbon enters the microwave pyrolysis chamber 3 through the molding discharge port 22 and the pyrolysis feed inlet 31. The microwave generator 33 is controlled by the microwave control unit 37 to operate, so that the temperature inside the microwave pyrolysis chamber 3 reaches the set temperature, and the extruded primary carbon is subjected to microwave pyrolysis. The pyrolysis gas generated by pyrolysis enters the condenser 45 through the pyrolysis gas discharge port 32. Part of the pyrolysis gas is condensed and stored in the oil storage tank 46, and the uncondensed pyrolysis gas enters the electromagnetic induction deep cracking chamber 4 through the volatile matter feed inlet 41. The second electromagnetic induction control unit 43 is used to control the operation of the second electromagnetic induction coil 42, so that the temperature inside the electromagnetic induction deep cracking chamber 4 reaches the set temperature, and the pyrolysis gas is deeply cracked to be converted into combustible gas. The combustible gas enters the gas purification system 5 through the combustible gas outlet 44 for purification and is finally collected in the gas collection tank 6.

[0097] In some embodiments, the negative pressure electromagnetic induction heating unit further includes:

[0098] A spiral feed rod 16, located inside the electromagnetic induction heating chamber 1;

[0099] A feed motor 17, which is arranged on the electromagnetic induction heating chamber. The feed motor rotating shaft is connected to the spiral feed rod 16 to drive the spiral feed rod to rotate.

[0100] In some embodiments, the extrusion molding unit is a hydraulic or mechanical extrusion device.

[0101] In the above embodiments, in order to facilitate the feeding of straw, a spiral feed rod 16 and a feed motor 17 are also provided. The rotation of the feed motor drives the rotation of the spiral feed rod 16 to realize the feeding of straw.

[0102] In some embodiments, a stirrer 34 is further provided inside the microwave pyrolysis chamber 3. The stirrer 34 is connected to the rotating shaft of the stirring motor 36 arranged outside the microwave pyrolysis chamber 3. During the microwave pyrolysis process, the rotation of the stirring motor 36 drives the rotation of the stirrer 34 to stir the extruded primary carbon.

[0103] In some embodiments, a secondary carbon discharge port 35 is further provided on the microwave pyrolysis chamber 3. After the microwave pyrolysis is completed, the secondary carbon obtained is discharged through the secondary carbon discharge port 35, and the released pyrolysis gas enters the electromagnetic induction deep cracking chamber 4 for high-temperature cracking.

[0104] In some embodiments, a microwave absorption device 38 is further provided on the microwave pyrolysis chamber 3.

[0105] The following further illustrates the preparation method and device of the high-value combustible gas of the present application with specific embodiments. This part further illustrates the content of the present invention in combination with specific embodiments, but should not be construed as a limitation to the present invention. Unless otherwise specified, the technical means adopted in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0106] Example 1

[0107] This embodiment provides a method for preparing high-value combustible gas, including the following steps:

[0108] S1. Crush the rice straw to 3 mm, then use the magnetic induction heating device to heat the straw to 300 °C, and keep it for 20 min in a negative pressure environment of -20 kPa to heat and dehydrate the straw and perform mild carbonization to obtain primary carbon; wherein, the power of the magnetic induction heating device is 20 kW, the frequency is 50 kHz, and the current is 10 A;

[0109] S2. Send the primary carbon to an extruder and extrude it into a rod shape at 10 Mpa; the diameter of the rod-shaped primary carbon is 20 mm, and the length is 80 ± 10 mm; place the extruded primary carbon in a microwave pyrolysis device and pyrolyze it at 500 °C for 5 min to release pyrolysis gas and obtain secondary carbon (i.e., biochar); wherein, the microwave power is 5 kW, and the microwave frequency is 2450 MHz;

[0110] S3. Collect the condensable components in the pyrolysis gas through a condenser to obtain tar, and introduce the non-condensable components in the pyrolysis gas into an electromagnetic induction heating device to crack at 800 °C for 10 min to be converted into combustible gas.

[0111] It can be understood that the preparation device of the high-value combustible gas as shown in Figure 1 can be used to prepare combustible gas according to the process parameters in Example 1.

[0112] Prepare combustible gas according to the method in Example 1. Among them, the biochar yield is 55%, the fixed carbon mass content in the biochar is 60%, and the calorific value of the combustible gas is 24 MJ / Nm 3 .

[0113] Comparative Example 1

[0114] This comparative example provides a method for preparing combustible gas, including the following steps:

[0115] S1. Crush rice straw to 3 mm, then use a magnetic induction heating device to heat the straw to 300 °C, and maintain it for 20 min in a negative pressure environment of -20 kPa to dehydrate and mildly carbonize the straw, obtaining primary carbon and partial pyrolysis gas. Among them, the power of the magnetic induction heating device is 20 kW, the frequency is 50 kHz, and the current is 10 A;

[0116] S2. Introduce the non-condensable components in the partial pyrolysis gas into an electromagnetic induction heating device, and pyrolyze them at 800 °C for 10 min to convert them into combustible gas.

[0117] According to the method in Comparative Example 1, the yield of primary carbon is 65%, the mass content of fixed carbon in the primary carbon is 35%, and the calorific value of the combustible gas is 15 MJ / Nm 3 .

[0118] Comparative Example 2

[0119] This comparative example provides a method for preparing combustible gas, including the following steps:

[0120] S1. Crush rice straw to 3 mm, then use a magnetic induction heating device to heat the straw to 300 °C, and maintain it for 20 min in a negative pressure environment of -20 kPa to dehydrate and mildly carbonize the straw, obtaining primary carbon. Among them, the power of the magnetic induction heating device is 20 kW, the frequency is 50 kHz, and the current is 10 A;

[0121] S2. Send the primary carbon to an extruder and extrude it into a rod shape at 10 Mpa. The diameter of the rod-shaped primary carbon is 20 mm, and the length is 80 ± 10 mm. Place the extruded primary carbon in a microwave pyrolysis device and pyrolyze it at 500 °C for 5 min to release pyrolysis gas and obtain secondary carbon (i.e., biochar). Among them, the microwave power is 5 kW, and the microwave frequency is 2450 MHz. Among them, the pyrolysis gas contains a condensable part (tar) and a non-condensable part (combustible gas). The combustible gas is the non-condensable gas collected after the pyrolysis gas is condensed (cool down and collect the oil).

[0122] According to the method in Comparative Example 2, the yield of biochar is 55%, the mass content of fixed carbon in the biochar is 60%, and the calorific value of the combustible gas is 18 MJ / Nm 3 .

[0123] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing high-value combustible gas, characterized in that: The following steps are involved: S1. Using an electromagnetic induction heating device under negative pressure to heat, dehydrate and lightly carbonize the straw to obtain primary charcoal; S2, after the primary carbon is extruded and formed, it is placed in a microwave pyrolysis device for pyrolysis, releasing pyrolysis gas and obtaining secondary carbon; S3, introducing the pyrolysis gas into an electromagnetic induction heating device for deep cracking and converting into combustible gas.

2. The method for preparing high-value combustible gas according to claim 1, characterized in that: The straw is heated to 200-300°C by a magnetic induction heating device and maintained at a negative pressure of -0.005MPa to -0.08MPa for 10-50 minutes to heat, dehydrate and lightly carbonize the straw to obtain primary charcoal; The power of the magnetic induction heating device is 10-30 kW, the frequency is 40-100 kHz, and the current is 10-30A.

3. The method for preparing high-value combustible gas according to claim 1, characterized in that: The primary carbon is extruded into a rod or block with a diameter of 10 to 30 mm, and placed in a microwave pyrolysis device to pyrolyze at 400 to 800° C. for 2 to 10 minutes to release pyrolysis gas and obtain secondary carbon; The microwave power of the microwave pyrolysis device is 3-10kW, and the microwave frequency is 2000-3000MHz.

4. The method for preparing high-value combustible gas according to claim 1, characterized in that: The pyrolysis gas is introduced into an electromagnetic induction heating device, cracked at 600-800° C. for 5-20 minutes, and converted into combustible gas.

5. The method for preparing high-value combustible gas according to claim 1, characterized in that: The method also includes cooling, dust removal and / or deacidification treatment of the obtained combustible gas.

6. A device for preparing high-value combustible gas for implementing the method according to any one of claims 1 to 5, characterized in that: include: A negative pressure electromagnetic induction heating unit is used to heat and dehydrate the straw under negative pressure and lightly carbonize it to obtain primary charcoal; An extrusion molding unit, used for extruding the primary carbon into a shape; A microwave pyrolysis unit is used to perform microwave pyrolysis on the primary char after extrusion; The electromagnetic induction deep cracking unit is used to deeply crack the pyrolysis gas produced during the microwave pyrolysis process.

7. The high-value combustible gas preparation device according to claim 6, characterized in that: The negative pressure electromagnetic induction heating unit comprises: An electromagnetic induction heating chamber has a straw feed port at one end and a primary charcoal discharge port at the other end; A first electromagnetic induction coil, which is arranged on the electromagnetic induction heating chamber; A first electromagnetic induction control unit, which is arranged on the electromagnetic induction heating chamber and is used to control the operation of the first electromagnetic induction coil; A negative pressure pump, located on the electromagnetic induction heating chamber, for evacuating the electromagnetic induction heating chamber; The extrusion molding unit has a primary carbon feed inlet and a molding outlet, and the primary carbon feed inlet is connected to the primary carbon outlet; The microwave pyrolysis unit comprises: A microwave pyrolysis cavity, on which a pyrolysis feed inlet and a volatile matter discharge port are provided, wherein the pyrolysis feed inlet is connected to the molding discharge port; A microwave generator is arranged on the microwave pyrolysis cavity; A microwave control unit, which is arranged on the microwave pyrolysis cavity and is used to control the operation of the microwave generator; The electromagnetic induction deep cracking unit comprises: An electromagnetic induction deep cracking chamber, on which a pyrolysis gas feed port is provided, the pyrolysis gas feed port being connected to the pyrolysis gas discharge port; A second electromagnetic induction coil, which is arranged on the electromagnetic induction deep cracking chamber; The second electromagnetic induction control unit is arranged on the electromagnetic induction deep cracking chamber and is used for controlling the operation of the second electromagnetic induction coil.

8. The high-value combustible gas preparation device according to claim 7, characterized in that: Also included is a gas processing unit, the gas processing unit comprising: A gas purification system, wherein one end of the electromagnetic induction deep cracking chamber away from the pyrolysis gas feed port is provided with a combustible gas outlet, and the combustible gas outlet is connected to the gas purification system for purifying the combustible gas; A gas collection tank is communicated with the gas purification system.

9. The high-value combustible gas preparation device according to claim 7, characterized in that: The electromagnetic induction deep cracking unit also includes: A condenser, the feed end of which is connected to the pyrolysis gas outlet; An oil storage tank, one end of which is connected to the discharge end of the condenser, and the other end of which is connected to the pyrolysis gas feed port.

10. The high-value combustible gas preparation device according to claim 7, characterized in that: The negative pressure electromagnetic induction heating unit also includes: A spiral feed rod is located in the electromagnetic induction heating chamber; A feeding motor is arranged on the electromagnetic induction heating chamber, and a rotating shaft of the feeding motor is connected to the spiral feeding rod to drive the spiral feeding rod to rotate; The microwave pyrolysis chamber is also provided with a stirrer; The microwave pyrolysis cavity is also provided with a secondary charcoal discharge port.

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