A method and apparatus for continuously producing cacl2

Abstract

The application discloses a device for continuously producing calcium carbide by using new energy abandoned electricity and adopting biomass as a carbon source and a method for continuously preparing CaC2 by using the device. The device is designed in a combined form of a CaO preheater, a biomass carbonization furnace and a plasma reactor and the like process units aiming at adopting biomass as a carbon source and plasma reaction as a main route for preparing calcium carbide, so as to complete the calcium carbide processing process. The reaction device and the method can obviously improve the production process of CaC2 by the combined design of the core reactor, the reaction speed is very fast, the residence time of the material is reduced, and the heat loss of the system can also be reduced; secondly, the biomass carbon is a green carbon source, the emission reduction effect can be achieved, and the use of new energy abandoned electricity also plays an energy-saving role.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of chemical synthesis, and in particular relates to a continuous preparation method and device of CaC2, and in particular to a continuous preparation method and device of CaC2 using new energy power and biomass carbon. BACKGROUND

[0002] Calcium carbide CaC2, commonly known as calcium carbide, is an important coal chemical product and basic chemical raw material. It is mainly used for the production of acetylene and acetylene-based chemical products, and has been hailed as the "mother of organic synthesis industry". The traditional production of CaC2 adopts a fixed bed moving bed, block-shaped raw material, and arc heating method. Due to the small contact area between block-shaped coke and CaO, the solid-solid phase reaction is severely limited by the transfer process, so that the industrial reaction needs to be carried out at high temperature, resulting in "long reaction time, low single furnace capacity, high energy consumption per ton as high as 3250 kWh, calcium carbide purity of about 80%, and thermal efficiency of only 50%". Developing a new energy-saving process has practical value.

[0003] Chinese patent CN116288415A introduces a new method for the electrolytic preparation of calcium carbide (CaC2). The method uses carbonaceous material as the cathode and a compound containing calcium ions as the molten salt. The cathode product is obtained at a temperature not exceeding 800°C. Although this method requires a low temperature, it cannot achieve continuous production and has high energy consumption. Chinese patent CN116239120A discloses a method for recycling the waste heat of liquid calcium carbide. The method mixes carbonaceous raw materials, calcium raw materials, catalysts, binders, and foaming agents uniformly, presses the mixture into a shaped material, and then performs heat treatment and waterproof treatment to obtain first calcium coke. Then, the first calcium coke is laid on the bottom of the calcium pot, and liquid calcium is added to make the first calcium coke react to synthesize calcium carbide, thereby obtaining solid calcium carbide and recycling the waste heat. This method requires manual operation in multiple batches and cannot achieve continuous production. In addition, the pressed block-shaped material affects the mass and heat transfer of the reaction, thereby affecting the overall performance of the process. The doctoral dissertation of Li Guodong, a doctoral student at Beijing University of Chemical Technology, titled "Basic Research on New Process for Preparing Calcium Carbide from Powdered Coke and Powdered Calcium Oxide" (Beijing University of Chemical Technology, June 2, 2011) mentions a new calcium carbide production process that uses powdered raw materials instead of block-shaped raw materials and uses the oxygen heating method instead of the electric arc method to reduce energy consumption and improve production efficiency. Although this method reduces energy consumption, it requires an oxygen production process that consumes a large amount of energy and chemical raw materials, and does not fully achieve energy saving. Various patents and researches are focused on energy saving, indicating that reducing the energy consumption of CaC2 in the production process is a key consideration in the process. In terms of carbon sources, existing technologies often directly use coke or activated carbon to improve the grade of the final product CaC2. Biomass also contains a large amount of carbon elements. Due to the collection radius within 100 kilometers, large-scale collection is costly and difficult to effectively utilize. There is no report on using biomass as a carbon source in the production of CaC2. Distributed calcium carbide production mode can better match the biomass carbon source.

[0004] At the same time, more new energy power generation systems are put into operation and deliver electricity to the grid. The main force in new energy power generation is wind power and photovoltaic power, and their installed capacity increases year by year. Wind and light in new energy are non-continuous resources, and power generation is affected by weather conditions, with certain periodic characteristics and large fluctuations. On the other hand, the law of electricity consumption also has periodic and fluctuating characteristics. This mismatch can result in a large amount of abandoned electricity that cannot be consumed on the grid. Using abandoned electricity for product conversion is an effective utilization method.

[0005] From the above existing technologies and developments, a calcium carbide production method that can combine new energy abandoned electricity and consider carbon emission reduction has the dual advantages of being green and low-carbon, and has great application prospects and potential. SUMMARY

[0006] Technical problem

[0007] The problems of the calcium carbide process at present include: high temperature, the existing process uses blocky raw materials and arc heating, which leads to the process needing to be carried out at high temperature, increasing energy consumption and investment cost. Due to the small specific surface of the blocky raw materials, the mass transfer and heat transfer efficiency is low, the reaction rate is slow, a higher reaction temperature is required, leading to high energy consumption, and the thermal efficiency of the product in the fixed bed process is only about 20%, which exists huge energy waste. The reaction rate of the blocky raw materials is slow, the reaction time is long, and the single furnace productivity is low. The equipment durability problem, the arc heating has high requirements for the equipment, and there is a problem of short service life of the equipment.

[0008] In view of the problems in the prior art, one object of the present application is to provide a device for continuously producing calcium carbide by using new energy abandoned electricity and adopting biomass as a carbon source. The device is designed in the form of combination of CaO preheater, biomass carbonization furnace / plasma reactor and other process units to complete the calcium carbide processing process, aiming at adopting biomass as a carbon source and plasma reaction as a main route for preparing calcium carbide.

[0009] Another object of the present application is to provide a method for continuously preparing CaC2 by using the device, which takes biomass char as a raw material, first prepares the biomass into coke powder in the presence of CaO through a pretreatment device, then sprays the coke powder loaded with CaO into a high-frequency plasma reactor to generate CaC2, H2, CO and the like, and completes the whole process through processes such as high-temperature separation of gas and solid phases, cooling and reuse of gas phase products.

[0010] Technical scheme

[0011] According to one aspect of the present application, the present application provides a device for continuously preparing calcium carbide, comprising a CaO preheating unit, a carbonization unit and a plasma reactor.

[0012] The CaO preheating unit comprises a feeding system, a CaO preheater and an oil gas burner system; the CaO preheater is in a cylindrical structure, the upper side of the CaO preheater is provided with a feeding port, the feeding port is connected with the feeding system, the bottom of the CaO preheater is provided with an air inlet, the air inlet is connected with the outlet of the oil gas burner, the top of the CaO preheater is provided with an air outlet for discharging tail gas, and the side of the middle part of the CaO preheater is provided with a discharging port for discharging the preheated materials;

[0013] The carbonization unit is located downstream of the CaO preheating unit, comprising a feeding system and a carbonization reactor, the carbonization reactor is a cylindrical structure, the height-diameter ratio of the cylindrical structure is between 3:1 and 6:1, the bottom of the carbonization reactor is provided with a gas inlet for inputting carrier gas, the upper side of the carbonization reactor is provided with a biomass feeding port, the biomass feeding port is connected with the feeding system, the middle side of the carbonization reactor is provided with a CaO feeding port, the CaO feeding port is connected with the discharge port of the CaO preheater through a pipeline to receive the preheated CaO from the CaO preheater, the top of the carbonization reactor is provided with a gas outlet for discharging pyrolysis gas, and the middle side of the carbonization reactor is also provided with a discharge port for discharging the pyrolysis material;

[0014] The plasma reactor is located downstream of the CaO preheating unit, the top of the plasma reactor is provided with a plasma generator, at least one feeding port is arranged on the upper side of the plasma reactor, the feeding port is connected with the discharge port of the carbonization reactor through a pipeline to receive the carbonized material from the carbonization unit; the upper side of the plasma reactor is provided with a gas outlet for discharging gas phase tail gas; the bottom side of the plasma reactor is provided with a gas inlet for introducing carrier gas into the plasma reactor; the middle part of the plasma reactor serves as the main reaction zone; a discharge port is arranged at the bottom of the plasma reactor for discharging a mixture containing product CaC2.

[0015] Preferably, the feeding system in the CaO preheating unit comprises a hopper and a feeder, and the feeder supplies material to the CaO preheater through the feeding port of the CaO preheater. Further, the feeder includes but is not limited to pneumatic conveying, screw feeder, or star feeder.

[0016] Preferably, a gas distributor is arranged on the inner side of the lower part of the CaO preheater for controlling the uniformity of gas flow inside the CaO preheater.

[0017] Preferably, the gas outlet of the CaO preheater is connected with a filter, and the filter is used to remove solid particles in the gas phase tail gas.

[0018] Preferably, the oil and gas burner is connected with the gas outlet of the carbonization reactor through a pipeline to receive the pyrolysis tail gas from the gas outlet of the carbonization reactor.

[0019] Preferably, the feeding system in the carbonization unit comprises a hopper and a feeder, and the feeder supplies biomass raw material to the carbonization reactor through the feeding port of the carbonization reactor. Further, the feeder includes but is not limited to pneumatic conveying, screw feeder, or star feeder.

[0020] Preferably, the gas outlet of the carbonation reactor is connected with a filter for removing solid particles in the gas phase mixture.

[0021] Preferably, a gas distributor is arranged inside the lower part of the carbonation reactor for controlling the uniformity of gas flow inside the carbonation reactor.

[0022] Preferably, the gas outlet of the plasma reactor is connected with a filter for removing solid particles in the gas phase mixture.

[0023] Preferably, the filter includes but is not limited to a screen with a corresponding pore size, a cyclone separator, etc.

[0024] Preferably, the discharge outlet of the plasma reactor is connected with one or more receiving tanks for receiving and separating the product.

[0025] Preferably, the CaO preheater and the carbonation reactor are fluidized bed reactors.

[0026] Preferably, the gas distributor arranged in the CaO preheater and the carbonation reactor includes but is not limited to a perforated plate, a sieve plate, a bubble cap plate, etc.

[0027] Preferably, monitoring elements such as valves, thermometers, pressure gauges, etc. are arranged on each pipeline in the continuous calcium carbide production device for monitoring the delivery of materials and the operation of the system, for example, for controlling the flow of materials or the on-off of the pipeline.

[0028] According to another aspect of the present application, another object of the present application is to provide a method for continuously producing calcium carbide from biomass, which comprises the following steps:

[0029] 1) CaO particles are added to the hopper of the feeding system of the CaO preheater, biomass particles are added to the hopper of the feeding system of the carbonation reactor, then the entire continuous calcium carbide production device is sealed, and the air tightness of each unit is checked;

[0030] 2) The CaO preheater is connected with a gas inlet for introducing carrier gas, the carbonation reactor is connected with a gas inlet for introducing carrier gas, and the plasma reactor is connected with a gas inlet for introducing carrier gas, each unit is replaced, and after the entire reaction device is qualified for gas phase sampling, the continuous calcium carbide production device is started;

[0031] 3) The oil gas burner of the CaO preheating unit is started, high temperature flue gas is introduced into the CaO preheater, and when the specified reaction temperature is reached, the feeding system is opened, and CaO is added to the CaO preheater at a certain rate;

[0032] 4) When the CaO preheater is normally fluidized and reaches the specified temperature and material level, the connecting pipeline between the CaO preheater and the carbonization reactor is connected, the preheated CaO is introduced into the carbonization reactor, the feeding system of the carbonization unit is opened at the same time, the biomass particles are sent into the carbonization reactor, mixed with high-temperature CaO from the CaO preheater, and the carbonization reaction occurs. After a certain time of fluidized reaction, the solid mixture of biomass char powder and CaO is discharged from the carbonization reactor with the carrier gas, introduced into the plasma reactor through the pipeline, and the pyrolysis gas is discharged through the outlet gas at the top of the carbonization reactor. The pyrolysis oil or combustible gas in the fuel gas is recovered by condensation and returned to the oil gas burner for heating of the CaO preheater;

[0033] 5) The plasma reactor receives the solid mixture of biomass char powder and CaO from the carbonization reactor through the connecting pipeline, and the CaO and biomass char powder in the mixture react to generate CaC2 in the plasma reactor through high-frequency discharge of the plasma generator. The tail gas is discharged through the gas outlet at the top of the carbonization reactor.

[0034] 6) The product solid-phase mixture containing CaC2 discharged from the discharge port of the plasma reactor is cooled, and the product is subjected to flotation solid-phase separation to obtain calcium carbide products with a purity of more than 98% after treatment.

[0035] Preferably, the tail gas discharged from the gas outlet at the top of the carbonization reactor is filtered and pressurized to return to the oil gas burner of the CaO preheating unit as fuel to provide part of the heat energy for the system.

[0036] Preferably, the biomass particles are selected from one or more of corn stalks, rice husks, wood chips, and fruit shells of agricultural and forestry crops, and the average particle size is between 0.1 and 2 mm, and the optimal particle size is between 0.2 and 1 mm. Using raw materials in this particle size range can optimize the pyrolysis carbonization rate of biomass particles, the rate of generating CaC2 in the plasma reactor, and energy consumption.

[0037] Preferably, the reaction temperature of the CaO preheater is between 500°C and 1200°C, preferably between 800°C and 1000°C, and the reaction pressure is between 0.001 MPa and 0.1 MPa, preferably between 0.005 MPa and 0.05 MPa. In this preferred range, the conversion rate of the reaction product, the yield of the product, and the energy production are optimal.

[0038] Preferably, the CaO addition rate in the CaO preheater is 3-10 kg / h, and the feeding speed is controlled at a fuel mass ratio of 1:1-5:1.

[0039] Preferably, the mass ratio of CaO and biomass particles in the carbonization reactor is between 1:1 and 4:1, preferably between 1.5:1 and 2:1, the solid phase residence time is 1-30s, preferably 5-20s, and the product conversion rate, product yield and energy production are optimal within this residence time range.

[0040] Preferably, the carrier gas used in the method is selected from CO2, N2, Ar gas or a combination thereof.

[0041] Preferably, the relationship between the feed rate and the reactor power in the plasma reactor is 1-100 g / kw, and the optimal feed rate is 5-50 g / kw, corresponding to the same output, optimal raw material consumption and system energy consumption within the optimal ratio range.

[0042] Preferably, the reaction temperature in the plasma reactor is 1200-2400℃, and the optimal reaction temperature is 1400-1800℃, and the product conversion rate, product yield and energy production are optimal under this reaction condition.

[0043] Preferably, the plasma generator in the plasma reactor uses abandoned electricity from wind power or solar power as energy.

[0044] Preferably, the tail gas discharged from the gas outlet of the plasma reactor enters the separation system after passing through the filter, and the combustible gas is collected and introduced into the oil gas burner as fuel.

[0045] Advantages

[0046] The reaction device and method of the present application are aimed at the continuous preparation of CaC2 reaction process, especially for the use of biomass carbon source and new energy abandoned electricity. Through the combination design of the core reactor, the production process of CaC2 is significantly better than that of the traditional fixed bed electric heating method for preparing calcium carbide. The reaction process is divided into multiple reaction processes. The high temperature CaO provided by the CaO preheater provides the heat source, the energy comes from biomass pyrolysis oil gas or external energy, and the biomass and other raw materials are first carbonized in the carbonization reactor, which realizes the attachment and distribution of CaO on the biomass carbon, solves the problems of proportioning and mass transfer of the two substances in the plasma reactor, and maximizes the mass transfer reaction rate of the powder. The efficiency of the plasma reactor is most effectively utilized, the reaction speed of the plasma reactor is very fast, the residence time of the material is reduced, and the heat loss of the system is also reduced; secondly, the biomass carbon is a green carbon source, which can achieve the effect of emission reduction, and the use of new energy abandoned electricity also plays a role in energy saving. BRIEF DESCRIPTION OF DRAWINGS

[0047] In the drawings, which are not necessarily drawn to scale, like numerals describe similar components throughout the several views. Like numerals having different letter extensions can represent different instances of the like component. The drawings illustrate generally, by way of example, various embodiments of the present application and are not intended to limit the present application in any way. The same or similar reference numerals and letters in different views represent the same or similar elements. Such embodiments do not represent all embodiments according to the present application in which all possible variations have not been described. These are exemplary, and other embodiments can develop as will be obvious to one skilled in the art from the following detailed description.

[0048] Figure 1 Structure diagram of a device for continuous production of CaC2 according to the present application.

[0049] Reference numerals:

[0050] CaO preheating unit:

[0051] 1-Feeding system: 11-Stock bin / storage tank, 12-Feeder / feed pump;

[0052] 2-Oil-gas burner;

[0053] 3-CaO preheater: 31-Feed inlet, 32-Discharge outlet, 33-Gas inlet, 34-Gas distributor, 35-Gas outlet, 36-Filter;

[0054] Carbonization unit:

[0055] 4-Feeding system: 41-Stock bin / storage tank, 42-Feeder / feed pump;

[0056] 5-Carbonization reactor: 50-CaO feed inlet, 51-Biomass feed inlet, 52-Discharge outlet, 53-Gas inlet, 54-Gas distributor, 55-Gas outlet, 56-Filter;

[0057] 6-Plasma reactor: 60-Feed inlet, 61-Gas inlet, 62-Discharge outlet, 63, 64-Collection tank, 65-Gas outlet, 66-Filter. DETAILED DESCRIPTION

[0058] Hereinafter, specific embodiments of the present application will be described in detail with reference to the accompanying drawings, but not as a limitation of the present application.

[0059] It is to be understood that various alterations can be made to the embodiments disclosed herein. Therefore, the following description is not meant to be limiting but is by way of example only. Other modifications made within the spirit and scope of the disclosure will be apparent to those skilled in the art.

[0060] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the present disclosure and, together with the general description of the disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the disclosure.

[0061] These and other features of the present invention will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0062] It should also be understood that although the present invention has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of the present invention, which have the features described in the claims and are therefore all within the scope of protection defined herein.

[0063] The above and other aspects, features and advantages of this disclosure will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0064] Specific embodiments of the present disclosure are described thereafter with reference to the accompanying drawings; however, it should be understood that the disclosed embodiments are merely examples of the present disclosure and can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that could obscure the present disclosure. Therefore, the specific structural and functional details disclosed herein are not intended to be limiting, but merely to serve as the basis and representative basis for the claims to teach those skilled in the art to use the present disclosure in a variety of substantially any suitable detailed structures.

[0065] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in other embodiments,” all of which may refer to one or more of the same or different embodiments according to this disclosure.

[0066] The following is for reference. Figure 1 The structure of the continuous reaction preparation method and apparatus for CaC2 of the present invention is described in detail, and it mainly includes: a CaO preheating unit, a carbonization reaction unit, a plasma reaction unit, etc.

[0067] The CaO preheating unit comprises a feeding system 1, a CaO preheater 3, and an oil-gas burner 2 system. The CaO preheater 1 is cylindrical, with a feed inlet 31 on its upper side, which is connected to the feeding system 1. The CaO preheater 3 has an air inlet 33 at its bottom, which is connected to the outlet of the oil-gas burner 2. The CaO preheater 3 has an air outlet 35 at its top for discharging exhaust gas, and an outlet 32 ​​on its middle side for discharging preheated material.

[0068] Preferably, the feed system 1 comprises a bin or silo 11 and a feeder or feed pump 12, which supplies the CaO preheater 3 through the feed inlet 31 of the CaO preheater 3. The feeder or feed pump 12 includes, but is not limited to, pneumatic conveying, screw feeder, or star feeder.

[0069] Preferably, the CaO preheater 3 is internally provided with a gas distributor 34 at the lower side, which controls the hot gas flow into the interior of the CaO preheater 3, so as to uniformly fluidize the interior of the CaO preheater 3.

[0070] Preferably, the gas outlet 35 of the CaO preheater 3 is connected to a filter 36, which removes solid particles in the gas phase tail gas.

[0071] Preferably, the oil gas burner 2 can also be connected to the gas outlet 55 or the filter 56 of the carbonization reactor 5 through a pipeline, to receive the pyrolysis tail gas containing combustible oil gas from the carbonization reactor 5.

[0072] The carbonization unit is located downstream of the CaO preheating unit, and comprises a feed system 4 and a carbonization reactor 5. The carbonization reactor 5 has a cylindrical structure, and the height-diameter ratio of the cylindrical structure is between 3:1 and 6:1. The carbonization reactor 5 is provided with a gas inlet 53 at the bottom, which is used to input the carrier gas. The carbonization reactor 5 is provided with a biomass feed inlet 51 at the upper side, which is connected to the feed system 4. The carbonization reactor 5 is provided with a CaO feed inlet 50 at the middle side, which is connected to the discharge outlet 32 of the CaO preheater 3 through a pipeline, to receive the preheated CaO from the CaO preheater 3. The carbonization reactor 5 is provided with a gas outlet 55 at the top, which is used to discharge the pyrolysis gas. The carbonization reactor 5 is also provided with a discharge outlet 52 at the middle side, which is used to discharge the pyrolysis material.

[0073] Preferably, the feed system 4 in the carbonization unit comprises a bin / silo 41 and a feeder / feed pump 42, which supplies the biomass raw material to the carbonization reactor 5 through the feed inlet 51 of the carbonization reactor 5. Further, the feeder / feed pump 42 includes, but is not limited to, pneumatic conveying, screw feeder, or star feeder.

[0074] Preferably, the gas outlet 55 of the carbonization reactor 5 is connected to a filter 56, which removes solid particles in the gas phase mixture.

[0075] Preferably, the carbonization reactor 5 is internally provided with a gas distributor 54 at the lower side, which controls the hot gas flow into the interior of the carbonization reactor 5, so as to uniformly fluidize the interior of the carbonization reactor 5.

[0076] The plasma reactor 6 is located downstream of the CaO preheating unit, and is provided with a plasma generator at the top, at least one feed inlet 60 on the upper side, which is connected to the discharge outlet 52 of the carbonization reactor 5 through a pipeline to receive the carbonized material from the carbonization unit, a gas outlet 65 on the upper side for discharging the gas phase tail gas, and a gas inlet 61 on the bottom side for introducing the carrier gas into the plasma reactor 6. The middle part of the plasma reactor 6 serves as the main reaction zone, and a discharge outlet 62 is provided at the bottom for discharging the mixture containing the product CaC2.

[0077] Preferably, the carrier gas in the plasma reactor 6 can also be introduced into the plasma reactor 6 through the feed inlet 60 together with the material from the carbonization reactor 5 through a pipeline.

[0078] Preferably, the gas outlet 65 of the plasma reactor 6 is connected to a filter 66 for removing solid particles in the gas phase mixture.

[0079] Preferably, the discharge outlet 62 of the plasma reactor 6 is connected to one or more receiving tanks 63 and 64 for receiving and separating the products.

[0080] Preferably, the CaO preheater 3 and the carbonization reactor 5 are fluidized bed reactors.

[0081] Preferably, the gas distributors 34 and 54 provided in the CaO preheater 3 and the carbonization reactor 5 include but are not limited to perforated plates, sieve plates, bubble cap plates, etc.

[0082] Preferably, the filters 36, 56 and 66 include but are not limited to screens with corresponding pore sizes, cyclone separators, etc.

[0083] Preferably, according to the needs, monitoring elements such as valves, thermometers, pressure gauges, etc. can be provided on each pipeline in the device for continuously preparing calcium carbide according to the present application, for monitoring the delivery of the material and the operation of the system, for example, for controlling the flow of the material or the on-off of the pipeline.

[0084] Reference Figure 1 The method for continuously preparing calcium carbide from biomass according to the present application comprises the following steps:

[0085] 1) CaO particles are added to the CaO preheater 3 in the feed system of the silo 11, biomass particles are added to the carbonization reactor 5 in the feed system of the silo 41, and then the entire continuous calcium carbide production device is sealed, the connecting pipeline valve between the CaO preheater 3 and the carbonization reactor 5 is closed, the connecting pipeline valve between the carbonization reactor 5 and the plasma reactor 6 is closed, and the gas tightness of each unit is checked, the gas is replaced, and the CO2 gas is introduced into the CaO preheater 3, the carbonization reactor 5 and the plasma reactor 6 respectively, and the gas tightness of each unit is checked;

[0086] 2) After the entire reaction device is qualified for gas phase sampling, the continuous calcium carbide production device is started;

[0087] 3) The oil and gas burner 2 of the CaO preheating unit is started, air and necessary fuel gas are introduced into it, the generated high-temperature flue gas is cut into the CaO preheater 3, and when the specified reaction temperature is reached, the feed system 1 is opened, and CaO is added to the CaO preheater 3 at a certain rate;

[0088] 4) When the CaO preheater 3 is normally fluidized and reaches the specified temperature and material level, the connecting pipeline between the CaO preheater 3 and the carbonization reactor 5 is connected, the preheated CaO is introduced into the carbonization reactor 5, the feed system 4 of the carbonization unit is opened at the same time, and the biomass particles are sent into the carbonization reactor 5 to mix with the high-temperature CaO from the CaO preheater 3 to occur carbonization reaction. After a certain time of fluidized reaction, the solid mixture of biomass coke powder and CaO is led out of the carbonization reactor 5 with the carrier gas, introduced into the plasma reactor 6 through the pipeline, and the pyrolysis gas is discharged through the outlet gas 55 at the top of the carbonization reactor 5. After condensation recovery, the pyrolysis oil or combustible gas in the fuel gas is recovered and returned to the oil and gas burner 2 for heating of the CaO preheater;

[0089] 5) The plasma reactor 6 receives the solid mixture of biomass coke powder and CaO from the carbonization reactor 5 through the connecting pipeline, and the CaO and biomass coke powder in the mixture are reacted in the plasma reactor 6 by high-frequency discharge of the plasma generator to generate CaC2, and the reaction tail gas is discharged through the gas outlet 65 at the top of the carbonization reactor 6.

[0090] 6) The product solid-phase mixture containing CaC2 discharged from the discharge port 62 of the plasma reactor 6 is cooled, the product is subjected to flotation solid-phase separation, and the calcium carbide product with a purity of more than 98% is obtained after treatment.

[0091] Preferably, the tail gas discharged from the gas outlet 55 at the top of the carbonization reactor 5 is filtered to remove dust and then pressurized to return to the oil gas burner 2 of the CaO preheating unit as fuel to provide part of the heat energy for the system.

[0092] Preferably, the biomass particles are selected from one or more of corn stalks, rice husks, etc., wood chips, fruit shells, and other agricultural and forestry crops, and the average particle size is between 0.1 and 2 mm, and the optimal particle size is between 0.2 and 1 mm. Using raw materials in this particle size range can optimize the pyrolysis carbonization rate of biomass particles, the rate of CaC2 generation in the plasma reactor, and energy consumption.

[0093] Preferably, the reaction temperature of the CaO preheater is between 500°C and 1200°C, preferably between 800°C and 1000°C, and the reaction pressure is between 0.001 MPa and 0.1 MPa, preferably between 0.005 MPa and 0.05 MPa. Within this preferred range, the conversion rate of the reaction product, the yield of the product, and the energy output are optimal.

[0094] Preferably, the feeding rate of CaO into the CaO preheater is between 3 kg / h and 10 kg / h, and the feeding speed is controlled to be between 1:1 and 5:1 with respect to the mass of the fuel.

[0095] Preferably, the mass ratio of CaO to biomass particles in the carbonization reactor is between 1:1 and 4:1, and the preferred mass ratio is between 1.5:1 and 2:1. The solid phase residence time is between 1 s and 30 s, and the preferred residence time is between 5 s and 20 s. Within this residence time range, the conversion rate of the reaction product, the yield of the product, and the energy output are optimal.

[0096] Preferably, the carrier gas used in the method is selected from CO2, N2, Ar gas, or a combination thereof.

[0097] Preferably, the relationship between the feeding rate and the reactor power in the plasma reactor is between 1 g / kw and 100 g / kw, and the optimal feeding rate is between 5 g / kw and 50 g / kw. Within this optimal ratio range, the same output, raw material consumption, and system energy consumption are optimal.

[0098] Preferably, the reaction temperature in the plasma reactor is between 1200°C and 2400°C, and the preferred reaction temperature is between 1400°C and 1800°C. Within this reaction condition, the conversion rate of the product, the yield of the product, and the energy output are optimal.

[0099] Preferably, the plasma generator in the plasma reactor preferably uses abandoned electricity from wind power or solar power generation as energy.

[0100] Preferably, after the tail gas discharged from the gas outlet of the plasma reactor passes through the filter, it enters the separation system, collects combustible gas, and is introduced into the oil gas burner for use as fuel.

[0101] The following examples are only listed as examples of embodiments of the present application, and do not constitute any limitation on the present application, and those skilled in the art can understand that modifications within the scope of the essence and concept of the present application fall within the protection scope of the present application. Unless otherwise specified, the reagents and instruments used in the following examples are commercially available products.

[0102] Example 1:

[0103] The CaO preheater is selected as: the reaction section is Φ100mm, the total length is about 800mm, it is a single-stage pressurized fluidized bed reactor, the material loading is about 3kg, the carbonization reactor is the same size as the CaO preheater, and the power of the plasma reactor is 10kW.

[0104] 1) After the system gas is replaced, start the oil gas burner 2 of the CaO preheating unit, introduce high temperature flue gas into the CaO preheater 3 through the gas inlet 33 of the CaO preheater 3, control the fuel flow at 0.1L / min, open the feeding system 1 to introduce CaO into the CaO preheater 3, and the addition rate is 3-10kg / h. When the CaO preheater 3 reaches the specified temperature, open the slide valve on the connecting pipeline between the CaO preheater 3 and the carbonization reactor 5, and continuously introduce the material into the carbonization reactor 5, and the discharge rate is equal to the feeding rate;

[0105] 2) Synchronously open the feeding system 4 of the carbonization reactor 5, introduce biomass particles between 0.1-2mm, and the optimal particle size is between 0.2-1mm, into the carbonization reactor 5, the biomass addition rate is 3-10kg / h, and the solid phase residence time is 10-100s. When the specified temperature is reached, open the connecting pipeline between the carbonization reactor 5 and the plasma reactor 6, and introduce the material into the plasma reactor 6;

[0106] 3) Start the plasma reactor 6, the plasma reactor power comes from new energy abandoned electricity, i.e. new energy electricity that cannot be connected to the grid. When the CaO and biomass carbon mixture is introduced into the plasma reactor 6, it reacts under the action of high-frequency current to generate CaC2, CO, H2 and other substances. CaC2 is liquid at high temperature, CaC2 small droplets enter the receiving tanks 63 and 64 through the discharge port 62, and become solid CaC2 particles under the action of cooling gas CO2, and are collected after cooling;

[0107] 4) The tail gas of the carbonization reactor 5 is biomass oil gas, which is returned to the oil gas burner 2 of the CaO preheating unit after purification, and is further burned to generate high temperature flue gas for heating CaO.

[0108] The above plasma reaction was carried out with three different ratios of CaO and biomass char, respectively, when the space velocity of the carbonization reactor 5 was 0.01 h -1 , the reaction temperature was 550°C, the pressure was 0.1 MPa, the reaction temperature of the plasma reactor 6 was 1500°C, and the pressure was 0.01 MPa, and the results were as follows:

[0109] Result 1: CaO and biomass char mass ratio was 2:1: biomass char conversion rate was 75%, CaC2 selectivity was 68%, and by-product selectivity was 32%;

[0110] Result 2: CaO and biomass char mass ratio was 3:1: biomass char conversion rate was 75%, CaC2 selectivity was 82%, and by-product selectivity was 18%;

[0111] Result 3: CaO and biomass char mass ratio was 4:1: biomass char conversion rate was 75%, CaC2 selectivity was 79%, and by-product selectivity was 21%.

[0112] Example 2:

[0113] The CaO preheater was selected as: reaction section Φ100 mm, total length about 800 mm, single-stage pressurized fluidized bed reactor, material loading about 3 kg, carbonization reactor and CaO preheater same size, plasma reactor power 10 kW.

[0114] 1) After the system gas is replaced, the oil gas burner 2 of the CaO preheating unit is started, high temperature flue gas is introduced into the CaO preheater 3 through the gas inlet 33 of the CaO preheater 3, the fuel flow is controlled at 0.1 L / min, the feeding system 1 is opened, CaO is introduced into the CaO preheater 3, the addition rate is 3-10 kg / h, when the CaO preheater 3 reaches the specified temperature, the slide valve on the connecting pipeline between the CaO preheater 3 and the carbonization reactor 5 is opened, and the material is continuously introduced into the carbonization reactor 5, and the discharge rate is equal to the feeding rate;

[0115] 2) The feeding system 4 of the carbonization reactor 5 is opened synchronously, biomass particles between 0.1-2 mm, and optimal particle size between 0.2-1 mm are introduced into the carbonization reactor 5, the biomass addition rate is 3-10 kg / h, and the solid phase residence time is 10-100 s, when the specified temperature is reached, the connecting pipeline between the carbonization reactor 5 and the plasma reactor 6 is opened, and the material is introduced into the plasma reactor 6;

[0116] 3) Start the plasma reactor 6. The power for the plasma reactor comes from renewable energy curtailment, i.e. renewable energy that cannot be connected to the grid. When the mixture of CaO and biomass carbon is introduced into the plasma reactor 6, it reacts under the action of high-frequency current to generate substances such as CaC2, CO, and H2. At high temperature, CaC2 is liquid. Small CaC2 droplets enter the receiving tanks 63 and 64 through the discharge port 62. Under the action of cooling gas CO2, they become solid CaC2 particles and are collected after cooling.

[0117] 4) The tail gas of the carbonization reactor 5 is biomass oil and gas. After purification, it is returned to the oil and gas burner 2 of the CaO preheating unit for further combustion to generate high-temperature flue gas, which is used to heat CaO.

[0118] The above-mentioned iso-CaC2 reaction was carried out using three different ratios of CaO and biochar, with the space velocity in the carbonization reactor being 0.01 h⁻¹. -1 The reaction temperature was 600℃ and the pressure was 0.1MPa. The reaction temperature in the plasma reactor was 1800℃ and the pressure was 0.01MPa. The results are as follows:

[0119] Result 1: The mass ratio of CaO to biomass carbon was 2:1; the biomass carbon conversion rate was 85%, the CaC2 selectivity was 70%, and the by-product selectivity was 30%.

[0120] Result 2: The mass ratio of CaO to biomass carbon was 3:1; the biomass carbon conversion rate was 89%, the CaC2 selectivity was 84%, and the by-product selectivity was 16%.

[0121] Result 3: The mass ratio of CaO to biomass carbon was 4:1; the biomass carbon conversion rate was 86%, the CaC2 selectivity was 80%, and the by-product selectivity was 20%.

[0122] Example 3:

[0123] The selected CaO preheater is a single-stage pressurized fluidized bed reactor with a reaction section of 100mm and a total length of about 800mm. The material loading is about 3kg. The carbonization reactor is the same size as the CaO preheater. The plasma reactor has a power of 10kW.

[0124] 1) After the system gas replacement, start the oil and gas burner 2 of the CaO preheating unit. High temperature flue gas is introduced into the CaO preheater 3 through the air inlet 33. The fuel flow rate is controlled at 0.1L / min. Start the feeding system 1 and introduce CaO into the CaO preheater 3 at a rate of 3-10kg / h. When the CaO preheater 3 reaches the specified temperature, open the slide valve on the connecting pipeline between the CaO preheater 3 and the carbonization reactor 5 to continuously introduce the material into the carbonization reactor 5. The discharge rate is controlled to be equal to the feeding rate.

[0125] 2) Synchronously open the feeding system 4 of the carbonization reactor 5, and introduce the biomass particles between 0.1 and 2 mm, preferably between 0.2 and 1 mm, into the carbonization reactor 5 at a rate of 3 to 10 kg / h, and the solid-phase residence time is 10 to 100 s. When the specified temperature is reached, open the connecting pipeline between the carbonization reactor 5 and the plasma reactor 6, and introduce the material into the plasma reactor 6;

[0126] 3) Open the plasma reactor 6, and the electric energy of the plasma reactor comes from new energy abandoned electricity, i.e. new energy electricity that cannot be connected to the grid. When the CaO and biomass carbon mixture is introduced into the plasma reactor 6, a reaction occurs under the action of high-frequency current, generating CaC2, CO, H2 and other substances. CaC2 is a liquid at high temperature, and the small droplets of CaC2 enter the receiving tanks 63 and 64 through the discharge port 62, and become solid-phase CaC2 particles under the action of the cooling gas CO2, and are collected after cooling;

[0127] 4) The tail gas of the carbonization reactor 5 is biomass oil gas, which is returned to the oil gas burner 2 of the CaO preheating unit after purification, and is further burned to generate high-temperature flue gas for heating CaO;

[0128] The above CaC2 reaction is carried out by using three different ratios of CaO and biomass carbon respectively. When the space velocity of the carbonization reactor is 0.01 h -1 -1, the reaction temperature is 550°C, the pressure is 0.1 MPa, the reaction temperature of the plasma reactor is 1500°C, and the pressure is 0.01 MPa, the following results are obtained:

[0129] Result 1: The mass ratio of CaO to coal coke is 3:1, the biomass carbon conversion rate is 75%, the CaC2 selectivity is 74%, and the byproduct selectivity is 26%;

[0130] Result 2: The mass ratio of CaO to biomass carbon is 3:1, the biomass carbon conversion rate is 75%, the CaC2 selectivity is 88%, and the byproduct selectivity is 12%;

[0131] Result 3: The mass ratio of CaO to petroleum coke is 3:1, the biomass carbon conversion rate is 75%, the CaC2 selectivity is 79%, and the byproduct selectivity is 21%.

[0132] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the present application. Although the present application is described in detail with reference to the above embodiments, those skilled in the art should understand that, within the scope of the spirit and principle of the present application defined by the claims, the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features thereof can be replaced by equivalent technical features, and these modifications or replacements are still within the scope of the present application defined by the claims.

Claims

1. A device for continuously preparing calcium carbide, comprising a CaO preheating unit, a carbonization unit and a plasma reactor; wherein The CaO preheating unit comprises a feeding system, a CaO preheater and an oil-gas burner system; The CaO preheater is in a cylindrical structure, and a feeding port is arranged on the upper side of the CaO preheater and connected with the feeding system; An air inlet is arranged at the bottom of the CaO preheater and connected with the outlet of the oil-gas burner, and an air outlet is arranged at the top of the CaO preheater for discharging tail gas; A discharging port is arranged on the side of the middle part of the CaO preheater for discharging preheated materials; The carbonization unit is located downstream of the CaO preheating unit and comprises a feeding system and a carbonization reactor; The carbonization reactor is in a cylindrical structure, and the height-diameter ratio of the cylindrical structure is 3: 1-6: 1; An air inlet is arranged at the bottom of the carbonization reactor for inputting carrier gas; A biomass feeding port is arranged on the upper side of the carbonization reactor and connected with the feeding system; A CaO feeding port is arranged on the side of the middle part of the carbonization reactor and connected with the discharging port of the CaO preheater through a pipeline to receive preheated CaO from the CaO preheater; An air outlet is arranged at the top of the carbonization reactor for discharging pyrolysis gas; A discharging port is arranged on the side of the middle part of the carbonization reactor for discharging pyrolyzed materials; The plasma reactor is located downstream of the CaO preheating unit, and a plasma generator is arranged at the top of the plasma reactor; At least one feeding port is arranged on the upper side of the plasma reactor and connected with the discharging port of the carbonization reactor through a pipeline to receive carbonized materials from the carbonization unit; An air outlet is arranged on the upper side of the plasma reactor for guiding gaseous tail gas out of the plasma reactor; An air inlet is arranged on the side of the bottom of the plasma reactor for inputting carrier gas into the plasma reactor; The middle part of the plasma reactor serves as a main reaction zone; A discharging port is arranged at the bottom of the plasma reactor for discharging a mixture containing product CaC2.

2. The apparatus for continuously producing calcium carbide according to claim 1, characterized by, The feeding system in the CaO preheating unit comprises a stock bin and a feeder, and the feeder supplies materials to the CaO preheater through the feeding port of the CaO preheater; The feeder is one of a pneumatic conveyor, a screw feeder and a star feeder; A gas distributor is arranged on the inner side of the lower part of the CaO preheater for controlling the uniformity of air flow in the CaO preheater; The air outlet of the CaO preheater is connected with a filter for removing solid particles in gaseous tail gas; The oil-gas burner is connected with the air outlet of the carbonization reactor through a pipeline to receive pyrolysis tail gas from the air outlet of the carbonization reactor; The feeding system in the carbonization unit comprises a stock bin and a feeder, and the feeder supplies biomass raw materials to the carbonization reactor through the feeding port of the carbonization reactor; The feeder is one of a pneumatic conveyor, a screw feeder and a star feeder. The gas outlet of the carbonization reactor is connected with a filter for removing solid particles in the gas phase mixture; A gas distributor is arranged inside the lower part of the carbonization reactor for controlling the uniformity of gas flow inside the carbonization reactor; The gas outlet of the plasma reactor is connected with a filter for removing solid particles in the gas phase mixture; The filter comprises a cyclone separator and a screen with a corresponding pore size; The discharge outlet of the plasma reactor is connected with one or more receiving tanks for receiving and separating the product; The CaO preheater and the carbonization reactor are fluidized bed reactors; The gas distributor arranged in the CaO preheater and the carbonization reactor is one of a perforated plate, a sieve plate and a bubble cap plate; Valves, thermometers and pressure gauges are arranged on each pipeline of the device for monitoring the delivery of materials and the operation of the system.

3. A method for continuously preparing calcium carbide by using the device of claim 2 and taking biomass as raw material, the method comprising the following steps: 1) CaO particles are added to the hopper of the feeding system of the CaO preheater, biomass particles are added to the hopper of the feeding system of the carbonization reactor, then the entire device for continuously preparing calcium carbide is sealed and the air tightness of each unit is checked; 2) carrier gas is introduced into the CaO preheater through the gas inlet, carrier gas is introduced into the carbonization reactor through the gas inlet, and carrier gas is introduced into the plasma reactor through the gas inlet, each unit is replaced, and the device for continuously preparing calcium carbide is started after the entire reaction device is qualified for gas phase sampling; 3) the oil gas burner of the CaO preheating unit is started, high temperature flue gas is introduced into the CaO preheater, and the feeding system is opened when the specified reaction temperature is reached, and CaO is added into the CaO preheater at a certain rate; 4) after the CaO preheater is normally fluidized and reaches the specified temperature and material level, the connecting pipeline between the CaO preheater and the carbonization reactor is connected, the preheated CaO is introduced into the carbonization reactor, the feeding system of the carbonization unit is opened at the same time, biomass particles are sent into the carbonization reactor, mixed with high temperature CaO from the CaO preheater, and carbonization reaction occurs, after a certain time of fluidized reaction, the solid mixture of biomass coke powder and CaO is introduced into the plasma reactor through the pipeline, the pyrolysis gas is discharged through the gas outlet at the top of the carbonization reactor, the pyrolysis oil or combustible gas in the fuel gas is recovered through condensation, and returned to the oil gas burner for heating of the CaO preheater; 5) the plasma reactor receives the solid mixture of biomass coke powder and CaO from the carbonization reactor through the connecting pipeline, the CaO and biomass coke powder in the mixture react to generate CaC2 in the plasma reactor through high frequency discharge of the plasma generator, and the reaction tail gas is discharged through the gas outlet at the top of the carbonization reactor. 6) The CaC2-containing product solid-phase mixture discharged from the discharge port of the plasma reactor is cooled, and the product is subjected to floatation solid-phase separation to obtain a calcium carbide product with a purity of 98% or higher.

4. The method for continuously producing calcium carbide using biomass as a raw material according to claim 3, characterized by, The tail gas discharged from the gas outlet at the top of the carbonization reactor is filtered to remove dust and then pressurized and returned to the oil-gas burner of the CaO preheating unit as fuel to provide part of the heat energy for the system; The biomass particles are selected from one or more of corn stalks, rice husks, wood chips, and fruit shells, and have an average particle size of 0.1-2 mm; The reaction temperature of the CaO preheater is 500-1200°C, and the reaction pressure is 0.001-0.1 MPa; The CaO addition rate in the CaO preheater is 3-10 kg / h; The mass ratio of CaO to biomass particles in the carbonization reactor is 1:1-4:1, and the solid-phase residence time is 1-30 s; The carrier gas used in the method is selected from CO2, N2, Ar gas, or a combination thereof; The relationship ratio between the feed rate and the reactor power in the plasma reactor is 1-100 g / kw; The reaction temperature in the plasma reactor is 1200-2400°C; The plasma generator in the plasma reactor uses abandoned electricity from wind power or solar power generation as energy; After the tail gas discharged from the gas outlet of the plasma reactor passes through the filter, it enters the separation system, collects combustible gas, and is introduced into the oil-gas burner for use as fuel.

5. The method for continuously preparing calcium carbide from biomass according to claim 4, characterized in that, The biomass particles have a particle size of 0.2-1 mm; The reaction temperature of the CaO preheater is 800-1000°C, and the reaction pressure is 0.005-0.05 MPa; The mass ratio of CaO to biomass particles in the carbonization reactor is 1.5:1-2:1, and the solid-phase residence time is 5-20 s; The relationship ratio between the feed rate and the reactor power in the plasma reactor is 5-50 g / kw; The reaction temperature in the plasma reactor is 1400-1800°C.

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