Novel electric heating tetrafluoroethylene cracking furnace

Abstract

The novel cracking furnace comprises an electric heating reactor, a mixer, an electric heating R22 preheater, an electric heating high-temperature steam furnace and a temperature control system, and the temperature control system is composed of a DCS control module, an R22 power supply control module, a power supply module, a steam furnace control module, a reactor power supply control module and a temperature signal transfer module; the DCS control module controls the R22 power supply control module, the power supply module, the steam furnace control module and the reactor power supply control module, and the temperature signal transfer module receives temperature information of the electric heating reactor, the electric heating R22 preheater and the electric heating high-temperature steam furnace in real time and transmits the temperature information to the DCS control module in real time. Through the temperature control system, accurate control over the temperature is achieved, byproducts are reduced, raw materials are saved, the product quality is improved, carbon emission is reduced, the system is more environmentally friendly, generation of waste acid water is reduced, the hazardous waste treatment cost is reduced, flammable and explosive fuel is not needed, an anti-explosion environment is changed into a common environment on site, the danger level is lowered, and the production safety is higher.

Description

Technical Field

[0001] The invention relates to the technical field of tetrafluoroethylene production equipment, in particular to a new type of cracking furnace for producing tetrafluoroethylene by electric heating. Background Art

[0002] Tetrafluoroethylene (TFE), a colorless and odorless gas, has a melting point of -142.5°C and a boiling point of -76.3°C. It is an important monomer for synthesizing polytetrafluoroethylene resin, as well as a monomer for synthesizing other fluoroplastics, fluororubbers, and perfluoropropylene. It is widely used in fluorosurfactants, fine chemicals, and medicines.

[0003] At present, the preparation method of tetrafluoroethylene at home and abroad mainly uses difluorochloromethane (R22) as raw material and undergoes thermal decomposition reaction at high temperature.

[0004] Reaction equation: 2CHClF2→CF2=CF2+2HCl. A platinum-lined tube is used as the cracking reaction tube, and superheated steam is used as the diluent. The cracking is carried out at a temperature of 600-900°C to obtain tetrafluoroethylene. After cooling and separation, water washing and alkali washing are performed to remove the hydrogen chloride therein, and then pressure distillation is performed at -20°C and 2.02MPa to obtain a polymerization grade pure product with a content of more than 99.9%.

[0005] However, the existing production process of tetrafluoroethylene cracking has the following defects:

[0006] 1. At present, the cracking furnace used in tetrafluoroethylene production uses natural gas or oil as fuel. The waste gas generated by its combustion is discharged into the atmosphere from the chimney, which will pollute the environment. Secondly, the use of natural gas or oil as fuel requires higher safety measures in the production workshop. The equipment and facilities used in the workshop must be explosion-proof. The price of explosion-proof equipment is high, which leads to increased production costs;

[0007] 2. The cracking furnace uses natural gas or oil as fuel, which results in uneven heating and makes it difficult to accurately control the temperature in the furnace. The temperatures in different areas of the furnace are different, and the by-products at different temperatures are also different, which leads to complex by-products during the cracking reaction, thus affecting the quality of the product.

[0008] 3. For cracking furnaces that use natural gas or oil as fuel, a large amount of waste acid water is produced after production, and the cost of hazardous waste treatment is high. Summary of the invention

[0009] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a new type of electric heating tetrafluoroethylene cracking furnace. Compared with the traditional production process, the system can achieve accurate control of the reaction temperature, reduce by-products, save raw materials, and improve product quality; there is no waste gas emission from fuel combustion, which reduces the generation of waste acid water and reduces environmental pollution; no flammable and explosive fuel is required, the site is changed from an explosion-proof environment to a general environment, the danger level is reduced, and the production safety is higher.

[0010] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0011] A novel electric heating tetrafluoroethylene cracking furnace comprises a cracking furnace body, wherein the cracking furnace body is composed of an electric heating reactor, a mixer, an electric heating R22 preheater, an electric heating high-temperature steam furnace and a temperature control system, wherein the temperature control system is composed of a DCS control module, an R22 power supply control module, a power supply module, a steam furnace control module, a reactor power supply control module and a temperature signal transfer module;

[0012] The DCS control module is used to control the R22 power supply control module, the power supply module, the steam furnace control module and the reactor power supply control module;

[0013] The temperature signal transfer module is used to receive the temperature information transmitted by the electric reactor, the electric R22 preheater and the electric high-temperature steam furnace in real time, and the temperature signal transfer module transmits the received temperature information to the DCS control module in real time;

[0014] The R22 power supply control module is used to control the heating of the electric R22 preheater and set the temperature of the electric R22 preheater;

[0015] The power supply module is used to supply power to the DCS control module, the R22 power supply control module, the steam furnace control module and the reactor power supply control module;

[0016] The steam furnace control module is used to control the heating of the electric high-temperature steam furnace and set the temperature of the electric high-temperature steam furnace;

[0017] The reactor power supply control module is used to control the heating of the electrothermal reactor and set the temperature of the electrothermal reactor;

[0018] The mixer is connected in series with the electrothermal reactor.

[0019] Further, the DCS control module controls the R22 power supply control module and the steam furnace control module to respectively start the electric R22 preheater and the electric high-temperature steam furnace for heating, and sets the temperatures of the electric R22 preheater and the electric high-temperature steam furnace to 450° C. and 950° C. respectively, and the temperature signal transfer module receives the temperature information at the outlets of the electric R22 preheater and the electric high-temperature steam furnace in real time, and transmits the received temperature information to the DCS control module in real time;

[0020] When in use, the DCS control module sets the temperature of the electric R22 preheater and the electric high-temperature steam furnace to 450°C and 950°C respectively through the R22 power supply control module and the steam furnace control module, and the temperature signal transfer module receives the temperature information at the outlet of the electric R22 preheater and the electric high-temperature steam furnace in real time;

[0021] 1. If the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric R22 preheater and the electric high-temperature steam furnace is lower than the set temperature, the DCS control module controls the electric R22 preheater and the electric high-temperature steam furnace to continue heating through the R22 power supply control module and the steam furnace control module respectively, until the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric R22 preheater and the electric high-temperature steam furnace reaches the set temperature, then the 950°C steam branches and the 450°C R22 branches are respectively merged and then enter the mixer for mixing, after proper heating, the mixed 950°C steam and 450°C R22 reach the reaction temperature, enter the electric reactor to start the electric thermal cracking reaction, and produce tetrafluoroethylene, and finally tetrafluoroethylene enters the cooling system and separation treatment equipment in turn;

[0022] 2. If the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric R22 preheater is lower than the set temperature, and the temperature at the outlet of the electric high-temperature steam furnace has reached the set temperature, the DCS control module controls the electric R22 preheater to continue heating through the R22 power supply control module, and the steam furnace control module controls the electric heating to reduce the input power, reduce the heating efficiency of the electric high-temperature steam furnace, and keep warm. After the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric R22 preheater reaches the set temperature, the 950°C steam branches and the 450°C R22 branches are respectively merged and then enter the mixer for mixing. After proper heating, the mixed 950°C steam and 450°C R22 reach the reaction temperature, and then enter the electric reactor to start the electric thermal cracking reaction to produce tetrafluoroethylene. Finally, tetrafluoroethylene enters the cooling system and separation treatment equipment in turn.

[0023] 3. If the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric high-temperature steam furnace is lower than the set temperature, and the temperature at the outlet of the electric R22 preheater has reached the set temperature, the DCS control module controls the electric high-temperature steam furnace through the steam furnace control module to continue heating, and the R22 power supply control module controls the electric R22 preheater to reduce the input power, reduce the heating efficiency of the electric R22 preheater, and keep warm. After the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric high-temperature steam furnace reaches the set temperature, the 950°C steam branches and the 450°C R22 branches are respectively merged and then enter the mixer for mixing. After proper heating, the mixed 950°C steam and 450°C R22 reach the reaction temperature, enter the electric reactor to start the electric thermal cracking reaction, and produce tetrafluoroethylene. Finally, tetrafluoroethylene enters the cooling system and separation and processing equipment in turn.

[0024] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0025] Compared with the traditional combustion cracking furnace;

[0026] 1. The temperature is precisely controlled by the temperature control system. The electric heating method is adopted to heat evenly, with small temperature differences in different areas, reducing by-products, saving raw materials and improving product quality;

[0027] 2. The electric heating method is adopted, which does not need to discharge combustion exhaust gas, reduces carbon emissions, is more environmentally friendly, and creates a green factory. At the same time, the temperature of R22 is accurately controlled to achieve an immediate reaction after confluence with high-temperature steam, which makes the reaction more complete, reduces steam waste, and thus reduces the generation of waste acid water and reduces the cost of hazardous waste treatment;

[0028] 3. The electric heating reactor adopts electric heating, which does not require flammable and explosive fuels. The site changes from an explosion-proof environment to a general environment, the danger level is reduced, and production safety is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and constitute limitations of the present invention. In the accompanying drawings:

[0030] Figure 1 It is a flow chart of the cracking furnace control system of the present invention. DETAILED DESCRIPTION

[0031] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as being limited to the examples set forth herein; on the contrary, these embodiments are provided so that the present invention will be more comprehensive and complete, and the concept of the example embodiments will be fully conveyed to those skilled in the art. The described features, structures, or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present invention. However, those skilled in the art will appreciate that the technical solutions of the present invention may be practiced while omitting one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known technical solutions are not shown or described in detail to avoid obscuring various aspects of the present invention.

[0032] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be fixedly connected or set, or it can be detachably connected or set, or connected or set in one piece. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0033] According to an embodiment of the present invention, a new type of cracking furnace for producing tetrafluoroethylene by electric heating is provided.

[0034] Example:

[0035] like Figure 1 As shown, a new type of electric heating tetrafluoroethylene cracking furnace includes a cracking furnace body, which is composed of an electric heating reactor, a mixer, an electric heating R22 preheater, an electric heating high-temperature steam furnace and a temperature control system. The temperature control system is composed of a DCS control module, an R22 power supply control module, a power supply module, a steam furnace control module, a reactor power supply control module and a temperature signal transfer module;

[0036] The DCS control module is used to control the R22 power control module, power supply module, steam furnace control module and reactor power control module;

[0037] The temperature signal transfer module is used to receive the temperature information transmitted by the electric reactor, electric R22 preheater and electric high-temperature steam furnace in real time. The temperature signal transfer module transmits the received temperature information to the DCS control module in real time;

[0038] The R22 power supply control module is used to control the heating of the electric R22 preheater and set the temperature of the electric R22 preheater;

[0039] The power supply module is used to supply power to the DCS control module, the R22 power supply control module, the steam boiler control module and the reactor power supply control module. The power supply module is a 10 / 0.38kV dedicated substation without a magnetic voltage regulator, eliminating the primary loss and reducing power loss. The R22 power supply control module, the steam boiler control module and the reactor power supply control module supply electricity to the electric R22 preheater, the electric high-temperature steam boiler and the electric reactor respectively;

[0040] The steam furnace control module is used to control the heating of the electric high-temperature steam furnace and set the temperature of the electric high-temperature steam furnace;

[0041] The reactor power control module is used to control the heating of the electric reactor and set the temperature of the electric reactor. The electric reactor adopts electric heating. The heat distribution in the reactor is uniform, and the temperature difference in each area is small, which reduces by-products, saves raw materials, and improves product quality. In addition, no flammable and explosive fuel is required. There are no flammable and explosive materials in the workshop, the danger level is reduced, and production safety is higher. At the same time, all lighting fixtures, maintenance boxes, socket boxes, terminal boxes, control boxes, cable connectors, substations, etc. do not need to use explosion-proof equipment, and the cost of equipment and facilities is reduced;

[0042] The mixer is connected in series with the electric heating reactor. Six main branch pipes are arranged on the mixer. Two branch pipes are arranged at the other end of each group of main branch pipes. One branch pipe is connected to high-temperature steam, and the other branch pipe is connected to high-temperature R22. High-temperature steam and high-temperature R22 are respectively introduced into the main branch pipe through their respective branch pipes, and then mixed in the main branch pipe and then mixed in the mixer. Finally, they are concentrated from the mixer into the electric heating reactor.

[0043] Compared with the traditional mixer with only two large pipes (one for high-temperature steam and one for high-temperature R22, the high-temperature steam and high-temperature R22 are mixed in the mixer), the mixer with six main branch pipes has more uniform contact and mixing, which is conducive to faster reaction in subsequent steps;

[0044] The DCS control module controls the R22 power supply control module and the steam furnace control module to start the electric R22 preheater and the electric high-temperature steam furnace heating respectively, and sets the temperatures of the electric R22 preheater and the electric high-temperature steam furnace to 450°C and 950°C respectively. The temperature signal transfer module receives the temperature information at the outlets of the electric R22 preheater and the electric high-temperature steam furnace in real time, and transmits the received temperature information to the DCS control module in real time.

[0045] When in use, the DCS control module sets the temperature of the electric R22 preheater and the electric high-temperature steam furnace to 450°C and 950°C respectively through the R22 power supply control module and the steam furnace control module, and accurately controls the temperature of R22 and high-temperature steam, so that R22 and high-temperature steam react immediately after merging, steadily reducing the waste of high-temperature steam, and thus reducing the generation of waste acid water;

[0046] If the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperatures at the outlets of the electric R22 preheater and the electric high-temperature steam furnace are both lower than the set temperature, the DCS control module controls the electric R22 preheater and the electric high-temperature steam furnace to continue heating through the R22 power supply control module and the steam furnace control module respectively, until the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperatures at the outlets of the electric R22 preheater and the electric high-temperature steam furnace reach the set temperature, and then the 950°C steam branches and the 450°C R22 branches are respectively merged and then mixed in the mixer, and after proper heating, the mixed 950°C steam and 450°C R22 reach the reaction temperature, and then enter the electric reactor to start the electric thermal cracking reaction to produce tetrafluoroethylene, and finally the tetrafluoroethylene enters the cooling system and the separation and processing equipment in sequence;

[0047] If the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric R22 preheater is lower than the set temperature, and the temperature at the outlet of the electric high-temperature steam furnace has reached the set temperature, the DCS control module controls the electric R22 preheater to continue heating through the R22 power supply control module, and the steam furnace control module controls the electric heating to reduce the input power, reduce the heating efficiency of the electric high-temperature steam furnace, and keep warm. After the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric R22 preheater reaches the set temperature, the 950°C steam branches and the 450°C R22 branches are respectively merged and then enter the mixer for mixing. After proper heating, the mixed 950°C steam and 450°C R22 reach the reaction temperature, and then enter the electric reactor to start the electric thermal cracking reaction to produce tetrafluoroethylene. Finally, tetrafluoroethylene enters the cooling system and separation treatment equipment in sequence.

[0048] If the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric high-temperature steam furnace is lower than the set temperature, and the temperature at the outlet of the electric R22 preheater has reached the set temperature, the DCS control module controls the electric high-temperature steam furnace through the steam furnace control module to continue heating, and the R22 power supply control module controls the electric R22 preheater to reduce the input power, reduce the heating efficiency of the electric R22 preheater, and keep warm. After the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric high-temperature steam furnace reaches the set temperature, then the 950°C steam branches and the 450°C R22 branches are respectively merged and then enter the mixer for mixing. After proper heating, the mixed 950°C steam and 450°C R22 reach the reaction temperature, and then enter the electric reactor to start the electric thermal cracking reaction to produce tetrafluoroethylene. Finally, tetrafluoroethylene enters the cooling system and separation treatment equipment in turn.

[0049] Working principle of the present invention:

[0050] The power supply module composed of 10 / 0.38kV special substation is used to supply power to the DCS control module, R22 power control module, steam furnace control module and reactor power control module, and then the R22 power control module, steam furnace control module and reactor power control module supply electricity to the electric R22 preheater, electric high-temperature steam furnace and electric reactor respectively;

[0051] The DCS control module controls the heating of the electric reactor by controlling the reactor power control module and sets the temperature of the electric reactor. It starts the electric R22 preheater and the electric high-temperature steam furnace for heating respectively by controlling the R22 power control module and the steam furnace control module. At the same time, the temperatures of the electric R22 preheater and the electric high-temperature steam furnace are set to 450°C and 950°C respectively. The temperature signal transfer module receives the temperature information at the outlets of the electric R22 preheater and the electric high-temperature steam furnace and the temperature information of the electric reactor in real time, and transmits the received temperature information to the DCS control module in real time.

[0052] If the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperatures at the outlets of the electric R22 preheater and the electric high-temperature steam furnace are both lower than the set temperature, the DCS control module controls the electric R22 preheater and the electric high-temperature steam furnace to continue heating through the R22 power supply control module and the steam furnace control module respectively, until the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperatures at the outlets of the electric R22 preheater and the electric high-temperature steam furnace reach the set temperature, and then the 950°C steam branches and the 450°C R22 branches are respectively merged and then mixed in the mixer, and after proper heating, the mixed 950°C steam and 450°C R22 reach the reaction temperature, and then enter the electric reactor to start the electric thermal cracking reaction to produce tetrafluoroethylene, and finally the tetrafluoroethylene enters the cooling system and the separation and processing equipment in sequence;

[0053] If the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric R22 preheater is lower than the set temperature, and the temperature at the outlet of the electric high-temperature steam furnace has reached the set temperature, the DCS control module controls the electric R22 preheater to continue heating through the R22 power supply control module, and the steam furnace control module controls the electric heating to reduce the input power, reduce the heating efficiency of the electric high-temperature steam furnace, and keep warm. After the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric R22 preheater reaches the set temperature, the 950°C steam branches and the 450°C R22 branches are respectively merged and then enter the mixer for mixing. After proper heating, the mixed 950°C steam and 450°C R22 reach the reaction temperature, and then enter the electric reactor to start the electric thermal cracking reaction to produce tetrafluoroethylene. Finally, tetrafluoroethylene enters the cooling system and separation treatment equipment in sequence.

[0054] If the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric high-temperature steam furnace is lower than the set temperature, and the temperature at the outlet of the electric R22 preheater has reached the set temperature, the DCS control module controls the electric high-temperature steam furnace through the steam furnace control module to continue heating, and the R22 power supply control module controls the electric R22 preheater to reduce the input power, reduce the heating efficiency of the electric R22 preheater, and keep warm. After the temperature information transmitted to the DCS control module by the temperature signal transfer module shows that the temperature at the outlet of the electric high-temperature steam furnace reaches the set temperature, then the 950°C steam branches and the 450°C R22 branches are respectively merged and then enter the mixer for mixing. After proper heating, the mixed 950°C steam and 450°C R22 reach the reaction temperature, and then enter the electric reactor to start the electric thermal cracking reaction to produce tetrafluoroethylene. Finally, tetrafluoroethylene enters the cooling system and separation treatment equipment in turn.

[0055] Therefore, compared with the traditional combustion cracking furnace, the present invention realizes precise temperature control through the temperature control system, adopts the heating method of electric heating, and heats evenly, with small temperature differences in various areas, reducing by-products, saving raw materials, and improving product quality; the heating method of electric heating does not need to discharge combustion exhaust gas, reduces carbon emissions, is more environmentally friendly, and creates a green factory. At the same time, the temperature of R22 is precisely controlled to achieve immediate reaction after merging with high-temperature steam, which makes the reaction more complete, reduces steam waste, and further reduces the generation of waste acid water, reducing the cost of hazardous waste treatment; the electric thermal reactor adopts an electric heating method, does not require flammable and explosive fuels, and the site is changed from an explosion-proof environment to a general environment, the danger level is reduced, and the production safety is higher.

[0056] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0057] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, 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 novel electric heating tetrafluoroethylene cracking furnace, comprising a cracking furnace body, characterized in that: The cracking furnace body is composed of an electric reactor, a mixer, an electric R22 preheater, an electric high-temperature steam furnace and a temperature control system, and the temperature control system is composed of a DCS control module, an R22 power supply control module, a power supply module, a steam furnace control module, a reactor power supply control module and a temperature signal transfer module; The DCS control module is used to control the R22 power supply control module, the power supply module, the steam furnace control module and the reactor power supply control module; The temperature signal transfer module is used to receive the temperature information transmitted by the electric reactor, the electric R22 preheater and the electric high-temperature steam furnace in real time, and the temperature signal transfer module transmits the received temperature information to the DCS control module in real time; The R22 power supply control module is used to control the heating of the electric R22 preheater and set the temperature of the electric R22 preheater; The power supply module is used to supply power to the DCS control module, the R22 power supply control module, the steam furnace control module and the reactor power supply control module; The steam furnace control module is used to control the heating of the electric high-temperature steam furnace and set the temperature of the electric high-temperature steam furnace; The reactor power supply control module is used to control the heating of the electrothermal reactor and set the temperature of the electrothermal reactor; The mixer is connected in series with the electrothermal reactor.

2. The novel electric heating tetrafluoroethylene cracking furnace according to claim 1 is characterized in that: The DCS control module controls the R22 power supply control module and the steam furnace control module to respectively start the electric R22 preheater and the electric high-temperature steam furnace for heating, and sets the temperatures of the electric R22 preheater and the electric high-temperature steam furnace to 450°C and 950°C respectively. The temperature signal transfer module receives the temperature information at the outlets of the electric R22 preheater and the electric high-temperature steam furnace in real time, and transmits the received temperature information to the DCS control module in real time.

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