Process device and method for synthesizing chloroethylene by mercury-free catalysis
阅读说明：本技术 一种无汞催化合成氯乙烯的工艺装置及方法 (Process device and method for synthesizing chloroethylene by mercury-free catalysis ) 是由 宁小钢 刘延财 张宇 陈鹏 熊磊 慕毅 任志荣 叶鹏云 陈树培 刘建 袁丽华 于 2019-11-07 设计创作，主要内容包括：本发明公开了一种无汞催化合成氯乙烯的工艺装置,包括原料混合器和热水泵,原料混合器连接有混合气预热器,混合气预热器分别连接在前台转化器和后台转化器的物料进口,前台转化器和后台转化器的物料出口互连后连接在吸附装置上。本发明还提供了一种无汞催化合成氯乙烯的方法,乙炔与氯化氢在经原料气混合器混合后进入混合气预热器,预热后温度升至80-100℃；升温后的混合气进入前后台转化器进行催化反应。前后台转化器可根据工艺要求实现串联、并联或串并结合三种模式。无汞催化剂前期活性较高时,采用并联运行模式；进入后期活性较低时,采用串联或串并运行模式；这三种模式调节可充分发挥前台转化器中无汞催化剂催化能力,延长无汞催化剂的的运行寿命。(The invention discloses a process device for synthesizing chloroethylene by mercury-free catalysis, which comprises a raw material mixer and a hot water pump, wherein the raw material mixer is connected with a mixed gas preheater, the mixed gas preheater is respectively connected with material inlets of a foreground converter and a background converter, and material outlets of the foreground converter and the background converter are connected with each other and then connected onto an adsorption device. The invention also provides a method for synthesizing chloroethylene by mercury-free catalysis, wherein acetylene and hydrogen chloride are mixed by a raw material gas mixer and then enter a mixed gas preheater, and the temperature is raised to 80-100 ℃ after preheating; the heated mixed gas enters a front converter and a rear converter to carry out catalytic reaction. The front and back converters can realize three modes of series connection, parallel connection or series-parallel connection according to the process requirements. When the early activity of the mercury-free catalyst is higher, a parallel operation mode is adopted; when the activity is lower in the later period, a series or series-parallel operation mode is adopted; the three modes can fully exert the catalytic capability of the mercury-free catalyst in the front converter and prolong the service life of the mercury-free catalyst.)
1. The process device for synthesizing chloroethylene by mercury-free catalysis is characterized by comprising a raw material mixer (1) and a hot water pump (5), wherein the raw material mixer (1) is connected with a mixed gas preheater (2), the mixed gas preheater (2) is respectively connected with material inlets of a foreground converter (3) and a background converter (4), a material outlet of the foreground converter (3) is connected with a material inlet of the background converter (4), material outlets of the foreground converter (3) and the background converter (4) are connected with each other and then connected onto an adsorption device (9), an adsorption layer is arranged in the adsorption device (9), and columnar activated carbon and activated carbon fibers are filled in the adsorption layer;
a water return pipe port of the foreground converter (3) is connected with a steam-water mixer a (7), and the steam-water mixer a (7) is also connected with a steam bag a (10);
a water return pipe port of the background converter (4) is connected with a steam-water mixer b (8), and the steam-water mixer b (8) is also connected with a steam bag b (11);
the steam outlets of the steam packet a (10) and the steam packet b (11) are connected to a steam pipe network, the hot water outlet of the steam packet a (10) is communicated with the water feeding pipe port of the foreground converter (3) through a pipeline a, and the hot water outlet of the steam packet b (11) is communicated with the water feeding pipe port pipeline b of the background converter (4);
one end of the hot water pump (5) is connected with a hot water tank (6), the other end of the hot water pump is connected to a pipeline a and a pipeline b through pipelines, and each connecting pipeline is provided with a water replenishing valve;
a regulating valve c and a mixer (12) are sequentially arranged on a pipeline between the mixed gas preheater (2) and the background converter (4), and the mixer (12) is arranged close to the background converter (4); a switching valve f is arranged on a material outlet connecting pipeline of the foreground converter (3) and the background converter (4), a branch is also arranged on the material outlet connecting pipeline of the foreground converter (3) and the background converter (4), and is arranged in front of the switching valve f, and a regulating valve e is arranged on the branch and can be used for communicating the foreground converter (3) and the mixer (12);
a flow regulating valve a and a switch valve b are arranged on a pipeline connecting the material inlet and the material outlet of the foreground converter (3); and a switching valve d is arranged on a pipeline connected with a material outlet of the background converter (4).
2. A process unit for the mercury-free catalytic synthesis of vinyl chloride according to claim 1, characterized in that the adsorption unit (9) is adapted to adsorb active components lost during the reaction of the noble metal catalyst or in abnormal situations.
3. The process unit for synthesizing vinyl chloride by using mercury-free catalysis as claimed in claim 1, wherein pipelines of the steam outlets of the steam drum a (10) and the steam drum b (11) are respectively provided with a flow regulating valve g and a flow regulating valve h, and the flow regulating valves g and h are used for regulating the steam pressures of the steam drum a (10) and the steam drum b (11).
4. The process unit for mercury-free catalytic synthesis of vinyl chloride according to claim 1, wherein the temperature of the hot water in the converter is raised to the temperature required by the mercury-free catalyst by introducing steam into the steam-water mixer a (7) and the steam-water mixer b (8).
5. The method for synthesizing chloroethylene by mercury-free catalysis is characterized by comprising the following specific operation steps:
step 1: filling mercury-free catalysts in the tubes of the foreground converter and the background converter, respectively injecting hot water in a hot water tank into shells of the foreground converter and the background converter, a steam bag a and a steam bag b by using a hot water pump, and controlling the liquid levels of the two steam bags at 30-70%;
step 2: introducing steam through the two steam-water mixers to respectively heat the hot water sides of the two converters, wherein the temperature of the hot water sides of the converters is 110-185 ℃;
and step 3: mixing raw material gas acetylene and hydrogen chloride by a mixer, then preheating the mixture in a mixed gas preheater, and raising the temperature of the mixed gas to 80-100 ℃;
and 4, step 4: the gas preheated in the step 3 enters a foreground converter and a background converter, mercury-free catalysts are filled in the tubes of the foreground converter and the background converter, the reaction temperature of the tube pass of the converter is controlled at 260 ℃ under the action of 110 ℃ and 260 ℃ according to the performance requirements of different mercury-free catalysts, and the gas reacts to synthesize crude chloroethylene under the action of the mercury-free catalysts;
and 5: crude chloroethylene coming out from the front converter and the background converter enters an adsorption device through a pipeline, and the adsorption device adsorbs lost active components and then the active components come out of the device and enter a subsequent purification and rectification system to finally obtain refined chloroethylene.
6. The method for mercury-free catalytic synthesis of vinyl chloride according to claim 5, wherein the molar ratio of acetylene to hydrogen chloride in step 1 is 1: 1.05-1.25.
7. The method for the mercury-free catalytic synthesis of vinyl chloride according to claim 5, wherein the mercury-free catalyst is a series of catalysts for acetylene hydrochlorination, which do not contain mercury and other harmful heavy metals.
8. The method for mercury-free catalytic synthesis of vinyl chloride according to claim 5, wherein step 4 is specifically performed as follows:
when the early-stage activity of the mercury-free catalyst is high, a parallel operation mode is adopted, namely the regulating valves a and c and the switch valves b, d and f are opened, and the switch valve e is closed, so that the problem of low capacity during low-load operation in the induction period of the mercury-free catalyst can be solved; when the content of acetylene at the outlet of the parallel operation of the current background converter is higher than the process control index, a series-parallel combination operation mode is adopted, namely regulating valves a and c and switch valves b, d and e are opened, and a switch valve f is closed; when the activity of the mercury-free catalyst is low in the later operation stage or the single operation can not meet the process requirements, a series operation mode is adopted, namely the regulating valve c and the switch valve f are closed, and the regulating valve a and the switch valves b, d and e are opened.
9. The method for the mercury-free catalytic synthesis of vinyl chloride according to claim 5, wherein the heat of the converter reaction is carried into the steam drum a (10) and the steam drum b (11) mainly by the natural circulation of hot water, and then the heat is carried out by the steam generated by the steam-liquid separation.
Technical Field
The invention belongs to the technical field of acetylene method chloroethylene synthesis methods, and particularly relates to a process device for synthesizing chloroethylene by mercury-free catalysis, and a method for synthesizing chloroethylene by mercury-free catalysis.
Background
The production process of chloroethylene mainly comprises an acetylene method and an ethylene method in China, and is limited by the conditions of raw materials, and most of chloroethylene is prepared by the acetylene method in China, namely, chloroethylene is prepared by the synthetic reaction of acetylene gas and hydrogen chloride gas under the action of a catalyst. In fact, after the "water guarantee convention for mercury" comes into effect, the domestic calcium carbide process PVC industry is facing a great pressure on mercury pollution control, and reducing mercury consumption and mercury pollution is a problem to be solved urgently in health development of calcium carbide process PVC enterprises. In recent years, the research direction of domestic mercury-free catalysts is mainly divided into non-noble metal catalysts, noble metal catalysts and non-metal catalysts. At present, the activity, stability and activation conditions of different types of mercury-free vinyl chloride catalysts are greatly different. If the catalyst with higher reaction activity has more concentrated heat release, the requirement on the heat transfer capacity of the converter is correspondingly improved; for the catalyst with lower reaction activity, multi-stage conversion is needed to meet the requirements of process indexes; for the catalyst with the activation condition higher than that of the existing mercury catalyst, the temperature requirement on a heat transfer medium is relatively high; and for part of noble metal catalysts, the loss of active components still exists, which inevitably causes the increase of application cost. Based on this, the application requirement of the novel mercury-free catalyst cannot be met by adopting the existing mercury catalyst synthesis process. On the basis of the research of the mercury-free catalyst, the development of the matched application process technology is developed, which is beneficial to breaking through the technical bottleneck of the application of the mercury-free catalyst as soon as possible and realizing the industrialization of the mercury-free catalyst.
Disclosure of Invention
The invention aims to provide a process device for synthesizing chloroethylene by mercury-free catalysis, and solves the problem that the existing mercury catalyst synthesis process cannot meet the application of a novel mercury-free catalyst.
The invention also aims to provide a method for synthesizing vinyl chloride by mercury-free catalysis.
The first technical scheme adopted by the invention is that the process device for synthesizing vinyl chloride by mercury-free catalysis comprises a raw material mixer and a hot water pump, wherein the raw material mixer is connected with a mixed gas preheater, the mixed gas preheater is respectively connected with material inlets of a foreground converter and a background converter, material outlets of the foreground converter and the background converter are connected with each other and then connected onto an adsorption device, an adsorption layer is arranged in the adsorption device, and columnar activated carbon and activated carbon fibers are filled in the adsorption layer;
the water return pipe port of the foreground converter is connected with a steam-water mixer a which is also connected with a steam bag a,
a water return pipe port of the background converter is connected with a steam-water mixer b, and the steam-water mixer b is also connected with a steam bag b;
the steam outlets of the steam bag a and the steam bag b are connected to a steam pipe network, the hot water outlet of the steam bag a is communicated with the water feeding pipe port of the foreground converter through a pipeline a, and the hot water outlet of the steam bag b is communicated with the water feeding pipe port pipeline b of the background converter;
one end of the hot water pump is connected with a hot water tank, the other end of the hot water pump is respectively connected to the pipeline a and the pipeline b through connecting pipelines, and each connecting pipeline is provided with a water replenishing valve;
a regulating valve c and a mixer are sequentially arranged on a pipeline between the mixed gas preheater and the background converter, and the mixer is arranged close to the background converter; a gas phase outlet connecting pipeline of the foreground converter and the gas phase outlet connecting pipeline of the background converter are provided with a switch valve f, a material outlet connecting pipeline of the foreground converter and the material outlet connecting pipeline of the background converter are also provided with a branch, the branch is arranged in front of the regulating valve f, and a switch valve e is arranged on the branch and can be communicated with the foreground converter and the
the pipelines connected with the material inlet and the material outlet of the front converter are respectively provided with a flow regulating valve a and a switch valve b; and a flow regulating valve c and a switch valve d are arranged on a pipeline connected with a material outlet of the background converter.
The present invention is also characterized in that,
the adsorption device is used for adsorbing active components lost in the reaction process or abnormal conditions of the noble metal catalyst.
And the pipelines of the steam outlets of the steam packet a and the steam packet b are respectively provided with a flow regulating valve g and a flow regulating valve h, the flow regulating valves g and h are used for regulating the steam pressure of the steam packet a and the steam packet b, and the hot water temperature of the converter is controlled by regulating the pressure of the steam packet so as to adapt to the requirements of different mercury-free catalysts on the bed temperature.
The second technical scheme adopted by the invention is a method for synthesizing chloroethylene by mercury-free catalysis, which comprises the following specific operation steps:
step 1: filling mercury-free catalysts in the tubes of the foreground converter and the background converter, respectively injecting hot water in a hot water tank into shell sides of the foreground converter and the background converter, a steam bag a and a steam bag b by using a hot water pump, and controlling the liquid levels of the two steam bags at 30-70%;
step 2: introducing steam through the two steam-water mixers to respectively heat the hot water sides of the two converters, wherein the temperature of the hot water sides of the converters is 110-185 ℃;
and step 3: mixing raw material gas acetylene and hydrogen chloride by a mixer, then preheating the mixture in a mixed gas preheater, and raising the temperature of the mixed gas to 80-100 ℃;
and 4, step 4: the gas preheated in the step 3 enters a foreground converter and a background converter, mercury-free catalysts are filled in the tubes of the foreground converter and the background converter, the reaction temperature of the tube pass of the converter is controlled at 260 ℃ under the action of 110 ℃ and 260 ℃ according to the performance requirements of different mercury-free catalysts, and the gas reacts to synthesize crude chloroethylene under the action of the mercury-free catalysts;
and 5: crude chloroethylene coming out from the front converter and the background converter enters an adsorption device through a pipeline, and the adsorption device adsorbs lost active components and then the active components come out of the device and enter a subsequent purification and rectification system to finally obtain refined chloroethylene.
The present invention is also characterized in that,
in the
The mercury-free catalyst refers to a series of acetylene hydrochlorination catalysts which do not contain mercury and other harmful heavy metals.
The specific operation of the step 4 is as follows:
when the early-stage activity of the mercury-free catalyst is high, a parallel operation mode is adopted, namely the regulating valves a and c and the switch valves b, d and f are opened, and the switch valve e is closed, so that the problem of low capacity during low-load operation in the induction period of the mercury-free catalyst can be solved; when the content of acetylene at the parallel operation outlet of the current background converter is higher than a process control index, a series-parallel operation process is adopted, namely regulating valves a and c and switch valves b, d and e are opened, and a switch valve f is closed; when the activity of the mercury-free catalyst is low in the later operation stage or the single operation can not meet the process requirements, a series operation mode is adopted, namely the regulating valve c and the switch valve f are closed, and the regulating valve a and the switch valves b, d and e are opened.
The temperature of the hot water of the converter is raised to the temperature required by the mercury-free catalyst by introducing steam into the steam-water mixer a and the steam-water mixer b.
The heat of the converter reaction is mainly carried into the steam drum a and the steam drum b by means of natural circulation of hot water, and then steam is generated by steam-liquid separation to carry away the heat.
The invention has the beneficial effects that: the process device of the invention
1. The temperature control mode is flexible, the requirements of different mercury-free catalysts on the activation temperature and the reaction temperature can be met, and the method has wide applicability;
2. the process device can effectively solve the problems of low load in induction period and the influence of the serial operation of front and rear converters on the capacity of the device;
3. the process device adopts hot water natural circulation to transfer heat, avoids the problems of difficult type selection, high failure rate and high energy consumption of a hot water pump adopting a forced circulation mode, and simultaneously has good economical efficiency as byproduct steam enters a steam pipe network and is used for other production devices;
4. the process device effectively solves the problem of loss of active components of the noble metal catalyst, and reduces the cost of recycling the noble metal catalyst.
Drawings
FIG. 1 is a schematic structural diagram of a process unit for mercury-free catalytic synthesis of vinyl chloride according to the present invention.
In the figure, 1, a raw material gas mixer, 2, a mixed gas preheater, 3, a front stage converter, 4, a back stage converter, 5, a hot water pump, 6, a hot water tank, 7, steam-water mixers a and 8, steam-water mixers b and 9, an adsorption device, 10, steam bags a and 11, steam bags b and 12 and a mixer.
Detailed Description
The invention provides a process device for synthesizing chloroethylene by mercury-free catalysis, which has a specific structure shown in figure 1 and comprises a
the water return pipe mouth of the foreground converter 3 is connected with a steam-water mixer a7, the steam-water mixer a7 is also connected with a steam bag a10,
a water return pipe port of the background converter 4 is connected with a steam-water mixer b8, and a steam bag b11 is also connected with the steam-
the steam outlets of the steam bag a10 and the steam bag b11 are connected to a steam pipe network, the hot water outlet of the steam bag a10 is communicated with the water feeding pipe port of the front converter 3 through a pipeline a, and the hot water outlet of the steam bag b11 is communicated with the water feeding pipe port pipeline b of the background converter 4;
one end of the
a regulating valve c and a
the pipelines connected with the material inlet and the material outlet of the foreground converter 3 are provided with a flow regulating valve a and a switch valve b; and a flow switch d is arranged on a pipeline connected with a material outlet of the background converter 4.
An adsorption layer is arranged in the adsorption device, and columnar activated carbon and activated carbon fibers are filled in the adsorption layer and used for adsorbing active components lost in the reaction process or abnormal conditions of the noble metal catalyst.
The pipelines of the steam packet a10 and the steam packet b11 are also respectively provided with a flow regulating valve g and a regulating valve h, and the flow regulating valves are used for regulating the steam pressure of the steam packet a10 and the steam packet b11 so as to control the hot water temperature of the converter.
A method for synthesizing chloroethylene by mercury-free catalysis comprises the following specific operation steps:
step 1: filling mercury-free catalysts in the tubes of the foreground converter and the background converter, respectively injecting hot water in a hot water tank into shells of the foreground converter and the background converter, a steam bag a and a steam bag b by using a hot water pump, and controlling the liquid levels of the two steam bags at 30-70%;
step 2: introducing steam through the two steam-water mixers to respectively heat the hot water sides of the two converters, wherein the temperature of the hot water sides of the converters is 110-185 ℃;
and step 3: mixing raw material gas acetylene and hydrogen chloride by a mixer, then preheating the mixture in a mixed gas preheater, and raising the temperature of the mixed gas to 80-100 ℃;
and 4, step 4: the gas preheated in the step 3 enters a foreground converter and a background converter, mercury-free catalysts are filled in the tubes of the foreground converter and the background converter, the reaction temperature of the tube pass of the converter is controlled at 260 ℃ under the action of 110 ℃ and 260 ℃ according to the performance requirements of different mercury-free catalysts, and the gas reacts to synthesize crude chloroethylene under the action of the mercury-free catalysts;
and 5: crude chloroethylene coming out from the front converter and the background converter enters an adsorption device through a pipeline, and the adsorption device adsorbs lost active components and then the active components come out of the device and enter a subsequent purification and rectification system to finally obtain refined chloroethylene.
In the
The mercury-free catalyst refers to a series of acetylene hydrochlorination catalysts which do not contain mercury and other harmful heavy metals.
The specific operation of the step 4 is as follows:
when the early-stage activity of the mercury-free catalyst is high, a parallel operation mode is adopted, namely the regulating valves a and c and the switch valves b, d and f are opened, and the switch valve e is closed, so that the problem of low capacity during low-load operation in the induction period of the mercury-free catalyst can be solved; when the content of acetylene at the parallel operation outlet of the current background converter is higher than a process control index, a series-parallel operation process is adopted, namely regulating valves a and c and switch valves b, d and e are opened, and a switch valve f is closed; when the activity of the mercury-free catalyst is low in the later operation stage or the single operation can not meet the process requirements, a series operation mode is adopted, namely the regulating valve c and the switch valve f are closed, and the regulating valve a and the switch valves b, d and e are opened.
The heat of the reaction of the converter is mainly carried into the steam pocket a10 and the steam pocket b11 by the natural circulation of hot water, and then the steam is generated by the steam-liquid separation to carry the heat away.
The technology of the invention is that acetylene and hydrogen chloride are mixed by a raw material gas mixer (the molar ratio of the acetylene to the hydrogen chloride is 1: 1.05-1.25, preferably 1: 1.05-1.1) and then enter a mixed gas preheater, and the temperature is raised to 80-100 ℃ after preheating; the heated mixed gas enters a front converter and a rear converter to carry out catalytic reaction. The front and back converters can realize three operation modes of series connection, parallel connection and series-parallel combination according to the process requirements. When the mercury-free catalyst is high in early activity, a parallel operation mode (namely, the regulating valves a and c and the switch valves b, d and f are opened, and the switch valve e is closed) is adopted, so that the influence of low-load operation in the induction period of the mercury-free catalyst and the influence of series operation of front and rear converters on the productivity can be avoided; when the content of acetylene at the parallel operation outlet of the current background converter is higher than a process control index, a series-parallel combined operation process is adopted, namely regulating valves a and c and switch valves b, d and e are opened, and a switch valve f is closed; according to the operating temperature of the background converter, a certain amount of mixed gas is supplemented through the regulating valve c, the mixed gas enters the background converter after being mixed by the
The temperature control method of the process system adopts natural circulation heat exchange, and the heat transfer medium is pure water. The reaction temperature of the converter can be flexibly controlled between 100 ℃ and 260 ℃ according to the performance requirement of the mercury-free catalyst. After filling of the mercury-free catalyst is finished, injecting pure water into a shell pass of the converter and a steam drum by using a hot water pump, wherein the liquid level of the steam drum is controlled to be 30-70%; then the hot water side of the converter is heated by introducing steam through a steam-water mixer. The temperature control mode solves the application problem of the mercury-free catalyst with higher activation temperature and reaction temperature, and is beneficial to the mercury-free catalyst to play a role of catalysis rapidly after the mixed gas is introduced.
The steam pocket in the process system is used for controlling the temperature of hot water of the converter, and the pressure of the steam pocket is adjusted by the flow adjusting valve on the steam outlet pipeline of the steam pocket in the operation process, so that the temperature of the hot water is adjusted, and the performance and the process control requirements of different mercury-free catalysts are met. The adjusting mode is flexible, simple and efficient.
The reaction heat in the process system is removed by the shell-side hot water of the converter, gas-liquid separation is realized in the steam bag, and the byproduct steam enters a steam pipe network through a pipeline and is used for other production devices. Meanwhile, a hot water pump continuously injects pure water to the hot water side of the converter so as to maintain the liquid level of the steam drum at 30-70%. The invention effectively solves the problem of utilization of synthesis reaction heat, and further improves the operation economy of the mercury-free catalyst.
The active carbon component in the adsorption device is used for adsorbing active components lost in the reaction process or abnormal conditions of the noble metal catalyst. The absorbent can be replaced after saturated absorption, and the active components absorbed in the absorbent are recovered, thereby solving the problem of higher production cost caused by the loss of the active components of the mercury-free catalyst.
- 上一篇：一种医用注射器针头装配设备
- 下一篇：一种液相法管道化连续分离生产氟化烷烃的装置