Method for controlling three-stage carbon dioxide hydrogenation reactor, electronic device, storage medium and ethylene production method by acetylene hydrogenation refining

Abstract

This invention discloses a control method, electronic equipment, storage medium, and a method for acetylene hydrogenation to ethylene production from a three-stage C2 hydrogenation reactor. The control method includes: controlling the inlet temperature of the first-stage C2 hydrogenation reactor based on the volume fraction of the product emanating from the first-stage reactor; controlling the inlet temperature of the second-stage C2 hydrogenation reactor based on the volume fraction of the product emanating from the second-stage reactor; and controlling the inlet temperature of the third-stage C2 hydrogenation reactor based on the volume fraction of the product emanating from the third-stage reactor. This invention solves the problem of ethylene loss due to over-hydrogenation in three-stage pre-hydrogenation C2 hydrogenation reactors, increasing the stability of ethylene production, lowering the reaction temperature compared to traditional methods, reducing the risk of temperature runaway, improving the selectivity and operational stability of the C2 hydrogenation reactor, and simultaneously reducing steam consumption by lowering the reaction temperature.

Description

Technical Field

[0001] This invention relates to the field of chemical engineering, and in particular to a control method, electronic equipment, storage medium, and method for acetylene hydrogenation to ethylene in a three-stage C2 hydrogenation reactor. Background Technology

[0002] The petrochemical industry plays a pivotal role in national economic and social development, contributing significantly to the country's economic progress. Ethylene is one of the most important products of the petrochemical industry. The three alkenes (ethylene, propylene, and butene) and three benzenes (benzene, toluene, and xylene) produced by ethylene plants are the most basic raw materials for petrochemicals and the foundation for producing various important organic chemical products. The level of ethylene production is a major indicator of a country's petrochemical development level.

[0003] The main feedstocks for ethylene plants include ethane, propane, butane, natural gasoline, naphtha, diesel, and hydrotreated tail oil. After steam cracking and separation, the C2 fraction contains ethylene, ethane, and a small amount of acetylene, with an acetylene content of approximately 0.2% to 1% (by volume). In the downstream polymerization reaction, ethylene poisons the polyolefin catalyst; therefore, acetylene must be removed to obtain polymerization-grade ethylene.

[0004] Currently, the removal of acetylene from cracked gas mainly employs two processes: solvent absorption and catalytic selective hydrogenation. Solvent absorption uses solvents such as dimethylformamide (DMF), acetone, and N-methylpyrrolidone (NMP) to absorb acetylene in the cracked gas for purification. Catalytic selective hydrogenation refers to the hydrogenation of acetylene to ethylene and ethane under specific process conditions in the presence of a hydrogenation catalyst, thereby achieving purification. The most widely used method for acetylene removal is catalytic selective hydrogenation, which can be further divided into pre-hydrogenation and post-hydrogenation depending on the process route. Pre-hydrogenation is suitable for pre-ethane removal and pre-propane removal processes. In this process, after alkaline washing, the cracked gas undergoes hydrogenation to remove alkynes without further distillation. The feed entering the reactor contains not only acetylene, ethylene, ethane, propylene, and propane, but also hydrogen and methane. Post-hydrogenation processes are applicable to sequential processes, hydrogenation processes after ethane removal, and hydrogenation processes after propane removal. They are processes in which the C2 fraction is separated and then an appropriate amount of hydrogen is added for hydrogenation.

[0005] Pre-hydrogenation processes utilize the hydrogen already present in the feedstock, eliminating the need for additional hydrogen in the C2 hydrogenation reactor. This simplifies the separation process, reduces equipment investment, and lowers energy consumption. Compared to post-hydrogenation, ethylene distillation columns do not require a pasteurization section or a second demethanizer to separate residual hydrogen and methane. Ethylene products are unaffected by impurities introduced with hydrogen, resulting in higher purity. However, pre-hydrogenation reactors have fewer control methods than post-hydrogenation reactors. The presence of a large amount of hydrogen in the feedstock, coupled with poor catalyst selectivity, can easily lead to over-hydrogenation, ethylene loss, or runaway reaction temperatures, resulting in catalyst bed overheating. Nevertheless, considering the investment and operating costs of the plant, pre-hydrogenation processes are currently widely adopted.

[0006] Under the action of a catalyst, acetylene in the C2 fraction is selectively hydrogenated to ethylene. The C2 hydrogenation reactor unit is a crucial step in the refining of ethylene products. Excessive hydrogenation of acetylene can lead to the formation of ethane from acetylene and ethylene, resulting in ethylene loss; or acetylene or dienes can undergo polymerization reactions to form oligomers or polymers, affecting the product's lifespan; or the catalyst activity can decrease, causing excessive acetylene concentration in the ethylene product, rendering it substandard. Therefore, the proper operation of the C2 hydrogenation reactor directly affects the operational stability and ethylene yield of the ethylene plant.

[0007] Currently, the active component of C2 hydrogenation catalysts is mainly palladium-based metals, with suppliers including CLARIANT, PHILLIPS, and Sinopec. The adsorption-desorption rates, thermodynamic parameters, process operating parameters, and process parameter sensitivity of C2 hydrogenation catalysts vary among companies, requiring precise adjustments and optimizations to ensure optimal hydrogenation performance, maximize ethylene selectivity, and increase ethylene production.

[0008] Currently, the parameters of C2 hydrogenation reactors are generally controlled manually by operators. Due to the long process, numerous control points, and complex processes in ethylene plants, and the limited manpower of personnel, it is impossible to monitor and optimize the C2 hydrogenation reactors in real time. At the same time, in order to ensure the quality of ethylene products and prevent acetylene leakage, operators make manual adjustments based on experience, which leads to the over-hydrogenation of acetylene to ethane, resulting in ethylene product loss, affecting ethylene yield, and causing one reactor bed to operate under overload, affecting the catalyst life cycle. At the same time, the ethane circulation volume increases, increasing the energy consumption of the unit. Summary of the Invention

[0009] Therefore, it is necessary to address the technical problem of existing C2 hydrogenation reactors requiring manual control of parameters by providing a control method, electronic equipment, storage medium, and acetylene hydrogenation refining method for a three-stage C2 hydrogenation reactor.

[0010] This invention provides a control method for a three-stage C2 hydrogenation reactor, comprising:

[0011] A method for controlling a three-stage C2 hydrogenation reactor, the three-stage C2 hydrogenation reactor comprising a first-stage C2 hydrogenation reactor, a second-stage C2 hydrogenation reactor, and a third-stage C2 hydrogenation reactor connected in series, the method comprising:

[0012] Monitor the volume fraction of the product effluent from the first-stage C2 hydrogenation reactor, and control the inlet temperature of the first-stage C2 hydrogenation reactor based on the volume fraction of the product effluent from the first-stage C2 hydrogenation reactor.

[0013] Monitor the volume fraction of the product effluent from the second-stage C2 hydrogenation reactor, and control the inlet temperature of the second-stage C2 hydrogenation reactor based on the volume fraction of the product effluent from the second-stage C2 hydrogenation reactor.

[0014] Monitor the volume fraction of acetylene at the outlet of the third-stage C2 hydrogenation reactor, and control the inlet temperature of the third-stage C2 hydrogenation reactor based on the volume fraction of the product at the outlet of the third-stage C2 hydrogenation reactor.

[0015] Further, controlling the inlet temperature of the first-stage C2 hydrogenation reactor based on the volume fraction of the product emanating from the first-stage C2 hydrogenation reactor includes:

[0016] The inlet temperature of the first-stage C2 hydrogenation reactor is gradually increased at a preset heating rate until the first-stage stopping heating condition is met. Then, the increase in the inlet temperature of the first-stage C2 hydrogenation reactor is stopped. The first-stage stopping heating condition is as follows:

[0017] After the ethylene volume fraction at the outlet of the first-stage C2 hydrogenation reactor begins to decrease, and the acetylene volume fraction is detectable at the outlet of the first-stage C2 hydrogenation reactor; or

[0018] After the volume fraction of ethane at the outlet of the first-stage C2 hydrogenation reactor begins to rise, and the volume fraction of acetylene at the outlet of the first-stage C2 hydrogenation reactor becomes detectable.

[0019] Furthermore, the step of controlling the inlet temperature of the first-stage C2 hydrogenation reactor based on the volume fraction of the product emanating from the first-stage C2 hydrogenation reactor further includes:

[0020] After stopping the increase in the inlet temperature of the first-stage C2 hydrogenation reactor, obtain the set range of acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor corresponding to the inlet temperature of the first-stage C2 hydrogenation reactor;

[0021] Calculate the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor based on the acetylene volume fraction at the inlet and outlet of the first-stage C2 hydrogenation reactor.

[0022] If the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor is not within the set range of the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor, an alarm operation will be executed.

[0023] Further, controlling the inlet temperature of the second-stage C2 hydrogenation reactor based on the volume fraction of the product emanating from the second-stage C2 hydrogenation reactor includes:

[0024] The inlet temperature of the second-stage C2 hydrogenation reactor is gradually increased at a preset heating rate until the second-stage heating stop condition is met. Then, the increase in the inlet temperature of the second-stage C2 hydrogenation reactor is stopped. The second-stage heating stop condition is as follows:

[0025] After the ethylene volume fraction at the outlet of the second-stage C2 hydrogenation reactor begins to decrease, and the acetylene volume fraction is detectable at the outlet of the second-stage C2 hydrogenation reactor; or

[0026] After the volume fraction of ethane at the outlet of the second-stage C2 hydrogenation reactor begins to rise, and the volume fraction of acetylene at the outlet of the second-stage reactor's C2 hydrogenation reactor becomes detectable.

[0027] Furthermore, the method of controlling the inlet temperature of the second-stage C2 hydrogenation reactor based on the volume fraction of the product emanating from the second-stage C2 hydrogenation reactor further includes:

[0028] After stopping the increase in the inlet temperature of the second-stage C2 hydrogenation reactor, obtain the set range of acetylene hydrogenation conversion rate of the second-stage C2 hydrogenation reactor corresponding to the inlet temperature of the second-stage C2 hydrogenation reactor;

[0029] Calculate the acetylene hydrogenation conversion rate of the second-stage C2 hydrogenation reactor based on the acetylene volume fraction at the inlet of the first-stage C2 hydrogenation reactor, the acetylene volume fraction at the outlet of the second-stage C2 hydrogenation reactor, and the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor.

[0030] If the acetylene hydrogenation conversion rate in the second-stage C2 hydrogenation reactor is not within the set range for the acetylene hydrogenation conversion rate in the second-stage C2 hydrogenation reactor, an alarm operation will be executed.

[0031] Further, controlling the inlet temperature of the third-stage C2 hydrogenation reactor based on the volume fraction of the product emanating from the third-stage C2 hydrogenation reactor includes:

[0032] The inlet temperature of the third-stage C2 hydrogenation reactor is gradually increased at a preset heating rate until the acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor is within the preset three-stage acetylene volume fraction range. Then, the increase in the inlet temperature of the third-stage C2 hydrogenation reactor is stopped. The three-stage acetylene volume fraction range is between (0, 1) ppm.

[0033] When there is no acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor, the inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor is calculated. If the inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor is greater than the temperature difference threshold, the inlet temperature of the third-stage C2 hydrogenation reactor is reduced until the inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor is less than or equal to the temperature difference threshold.

[0034] Furthermore, the temperature difference threshold is:

[0035]

[0036] Where △T is the temperature difference threshold, V 总 ΔH represents the molar flow rate of the feed to the third-stage C2 hydrogenation reactor. C2H2 The heat of hydrogenation of acetylene, ΔH MA The heat of hydrogenation of methylacetylene is ΔH. PD The heat of hydrogenation of propadiene, ΔH BD For the heat of hydrogenation of butadiene, F 总 M3 represents the mass flow rate of the feed to the third-stage C2 hydrogenation reactor, and Cp represents the mass of the third-stage C2 hydrogenation reactor. 总 To determine the specific heat capacity of the cracked gas entering the three-stage C2 hydrogenation reactor, C P3 Let X be the total specific heat capacity of the third-stage C2 hydrogenation reactor, k be the first temperature rise constant of the third-stage C2 hydrogenation reactor, l be the second temperature rise constant of the third-stage C2 hydrogenation reactor, m be the third temperature rise constant of the third-stage C2 hydrogenation reactor, a be the first heat coefficient of reaction of the third-stage C2 hydrogenation reactor, b be the second heat coefficient of reaction of the third-stage C2 hydrogenation reactor, c be the third heat coefficient of reaction of the third-stage C2 hydrogenation reactor, d be the fourth heat coefficient of reaction of the third-stage C2 hydrogenation reactor, and X be the... 3.C2H2 X represents the acetylene content at the inlet of the third-stage C2 hydrogenation reactor. 3.MA X represents the methylacetylene content at the inlet of the third-stage C2 hydrogenation reactor. 3.PD X represents the propadiene content at the inlet of the third-stage C2 hydrogenation reactor. 3.BD This refers to the butadiene content at the inlet of the third-stage C2 hydrogenation reactor.

[0037] This invention provides an electronic device, comprising:

[0038] At least one processor; and,

[0039] A memory communicatively connected to at least one of the processors; wherein,

[0040] The memory stores instructions that can be executed by at least one of the processors to enable at least one of the processors to perform the control method for the three-stage C2 hydrogenation reactor as described above.

[0041] The present invention provides a storage medium that stores computer instructions, which, when executed by a computer, are used to perform all steps of the control method for the three-stage C2 hydrogenation reactor as described above.

[0042] This invention provides a method for refining ethylene by hydrogenation of acetylene, applied to the hydrogenation process before an ethylene plant. The method employs the control method of the three-stage C2 hydrogenation reactor described above in the C2 hydrogenation system of the hydrogenation process before the ethylene plant.

[0043] This invention adjusts the operating conditions of each stage of the C2 hydrogenation reactor based on the changes in the inlet and outlet data of each stage. This allows for a reasonable distribution and setting of the load on each stage of the C2 hydrogenation reactor, solving the problem of ethylene loss caused by over-hydrogenation in the three-stage pre-hydrogenation C2 hydrogenation reactor. This results in increased and more stable ethylene production, a lower reaction temperature than traditional methods, and reduced risk of temperature runaway. It also improves the selectivity and operational stability of the C2 hydrogenation reactor. Furthermore, the lower reaction temperature reduces steam consumption and lowers the overall steam consumption of the reactor. Attached Figure Description

[0044] Figure 1 This is a flowchart illustrating the control method of a three-stage C2 hydrogenation reactor according to an embodiment of the present invention.

[0045] Figure 2 This is a flowchart illustrating the control method for a three-stage C2 hydrogenation reactor according to another embodiment of the present invention.

[0046] Figure 3 This is a schematic diagram of the three-stage C2 hydrogenation reactor of the present invention;

[0047] Figure 4 This is a schematic diagram of the hardware structure of an electronic device according to the present invention. Detailed Implementation

[0048] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. Identical components are indicated by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, while the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0049] like Figure 1 The diagram shown is a flowchart of a control method for a three-stage C2 hydrogenation reactor according to an embodiment of the present invention. The three-stage C2 hydrogenation reactor includes a first-stage C2 hydrogenation reactor, a second-stage C2 hydrogenation reactor, and a third-stage C2 hydrogenation reactor connected in series. The method includes:

[0050] Step S101: Monitor the volume fraction of the product at the outlet of the first-stage C2 hydrogenation reactor, and control the inlet temperature of the first-stage C2 hydrogenation reactor based on the volume fraction of the product at the outlet of the first-stage C2 hydrogenation reactor.

[0051] Step S102: Monitor the volume fraction of the product at the outlet of the second-stage C2 hydrogenation reactor, and control the inlet temperature of the second-stage C2 hydrogenation reactor based on the volume fraction of the product at the outlet of the second-stage C2 hydrogenation reactor.

[0052] Step S103: Monitor the volume fraction of acetylene at the outlet of the third-stage C2 hydrogenation reactor, and control the inlet temperature of the third-stage C2 hydrogenation reactor based on the volume fraction of the product at the outlet of the third-stage C2 hydrogenation reactor.

[0053] Specifically, the present invention can be applied to electronic devices with processing capabilities, such as the controller of a three-stage C2 hydrogenation reactor.

[0054] like Figure 3 The diagram shows a three-stage C2 hydrogenation reactor of the present invention, including a first-stage C2 hydrogenation reactor 1, a second-stage C2 hydrogenation reactor 2, and a third-stage C2 hydrogenation reactor 3. The initial feed temperature of the C2 hydrogenation reactors is lower than the starting temperature of the hydrogenation reaction, and the materials between each stage pass through a cooler process. The cracked gas enters the first-stage C2 hydrogenation reactor 1 through a heater 4, and after being cooled by a cooler 5, it enters the second-stage C2 hydrogenation reactor 2. Then, after being cooled by a cooler 6, it enters the third-stage C2 hydrogenation reactor 3, from which the product is output.

[0055] The control method first executes step S101, monitoring the volume fraction of the product emanating from the first-stage C2 hydrogenation reactor, and then controlling the inlet temperature of the first-stage C2 hydrogenation reactor based on this volume fraction. Specifically,

[0056] Specifically, the inlet temperature of the first-stage C2 hydrogenation reactor is gradually increased by 2℃ / h, for example, by increasing the inlet temperature of the first-stage C2 hydrogenation reactor through heater 4. Analytical data of the inlet and outlet of the first-stage C2 hydrogenation reactor are obtained, including the volume fractions of acetylene, ethylene, ethane, propylene, MAPD, and propane. The inlet temperature of the first-stage C2 hydrogenation reactor is controlled based on the volume fraction of the product at the outlet of the first-stage C2 hydrogenation reactor.

[0057] Then, step S102 is executed to monitor the volume fraction of the product emanating from the second-stage C2 hydrogenation reactor and control the inlet temperature of the second-stage C2 hydrogenation reactor based on the volume fraction of the product emanating from the second-stage C2 hydrogenation reactor.

[0058] Specifically, the inlet temperature of the second-stage C2 hydrogenation reactor is gradually increased by 2℃ / h, for example, by gradually increasing the inlet temperature of the second-stage C2 hydrogenation reactor through cooler 5. Analytical data of the inlet and outlet of the second-stage C2 hydrogenation reactor are obtained, including the volume fractions of acetylene, ethylene, ethane, propylene, MAPD, and propane. The inlet temperature of the second-stage C2 hydrogenation reactor is controlled based on the volume fraction of the product at the outlet of the second-stage C2 hydrogenation reactor.

[0059] Finally, step S103 is executed to monitor the acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor, and the inlet temperature of the third-stage C2 hydrogenation reactor is controlled based on the volume fraction of the product at the outlet of the third-stage C2 hydrogenation reactor.

[0060] Specifically, the inlet temperature of the third-stage C2 hydrogenation reactor is gradually increased by 2℃ / h, for example, by gradually increasing the inlet temperature of the second-stage C2 hydrogenation reactor through cooler 6. Analytical data of the inlet and outlet of the third-stage C2 hydrogenation reactor are obtained, including the volume fractions of acetylene, ethylene, ethane, propylene, MAPD, and propane. The inlet temperature of the third-stage C2 hydrogenation reactor is controlled based on the volume fraction of the product at the outlet of the third-stage C2 hydrogenation reactor.

[0061] This invention adjusts the operating conditions of each stage of the C2 hydrogenation reactor based on analytical data changes at the inlet and outlet. This allows for a more rational distribution and setting of the load on each stage, solving the problem of ethylene loss caused by over-hydrogenation in the pre-hydrogenation stage of the C2 hydrogenation reactor. This results in increased and more stable ethylene production, a lower reaction temperature compared to traditional methods, reduced temperature runaway, and improved selectivity and operational stability of the C2 hydrogenation reactor. Simultaneously, the lower reaction temperature reduces steam consumption, thus lowering the reactor's steam usage. Selectivity refers to the proportion of reactants that produce a specific target product. In this embodiment, acetylene hydrogenation can produce either ethylene or ethane; selectivity is the proportion of acetylene that produces ethylene.

[0062] like Figure 2 The diagram shown illustrates a workflow of a control method for a three-stage C2 hydrogenation reactor according to another embodiment of the present invention. The three-stage C2 hydrogenation reactor includes a first-stage C2 hydrogenation reactor, a second-stage C2 hydrogenation reactor, and a third-stage C2 hydrogenation reactor connected in series. The method includes:

[0063] Step S201: Monitor the volume fraction of the product emanating from the first-stage C2 hydrogenation reactor. Gradually increase the inlet temperature of the first-stage C2 hydrogenation reactor at a preset heating rate until the first-stage stopping heating condition is met. Then, stop increasing the inlet temperature of the first-stage C2 hydrogenation reactor. The first-stage stopping heating condition is:

[0064] After the ethylene volume fraction at the outlet of the first-stage C2 hydrogenation reactor begins to decrease, and the acetylene volume fraction is detectable at the outlet of the first-stage C2 hydrogenation reactor; or

[0065] After the volume fraction of ethane at the outlet of the first-stage C2 hydrogenation reactor begins to rise, and the volume fraction of acetylene at the outlet of the first-stage C2 hydrogenation reactor can be detected.

[0066] In one embodiment, controlling the inlet temperature of the first-stage C2 hydrogenation reactor based on the volume fraction of the product emanating from the first-stage C2 hydrogenation reactor further includes:

[0067] After stopping the increase in the inlet temperature of the first-stage C2 hydrogenation reactor, obtain the set range of acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor corresponding to the inlet temperature of the first-stage C2 hydrogenation reactor;

[0068] Calculate the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor based on the acetylene volume fraction at the inlet and outlet of the first-stage C2 hydrogenation reactor.

[0069] If the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor is not within the set range of the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor, an alarm operation will be executed.

[0070] Step S202: Monitor the volume fraction of the product emanating from the second-stage C2 hydrogenation reactor. Gradually increase the inlet temperature of the second-stage C2 hydrogenation reactor at a preset heating rate until the second-stage heating stop condition is met. Then, stop increasing the inlet temperature of the second-stage C2 hydrogenation reactor. The second-stage heating stop condition is:

[0071] After the ethylene volume fraction at the outlet of the second-stage C2 hydrogenation reactor begins to decrease, and the acetylene volume fraction is detectable at the outlet of the second-stage C2 hydrogenation reactor; or

[0072] After the volume fraction of ethane at the outlet of the second-stage C2 hydrogenation reactor begins to rise, and the volume fraction of acetylene at the outlet of the second-stage reactor's C2 hydrogenation reactor becomes detectable.

[0073] In one embodiment, controlling the inlet temperature of the second-stage C2 hydrogenation reactor based on the volume fraction of the product exiting the second-stage C2 hydrogenation reactor further includes:

[0074] After stopping the increase in the inlet temperature of the second-stage C2 hydrogenation reactor, obtain the set range of acetylene hydrogenation conversion rate of the second-stage C2 hydrogenation reactor corresponding to the inlet temperature of the second-stage C2 hydrogenation reactor;

[0075] Calculate the acetylene hydrogenation conversion rate of the second-stage C2 hydrogenation reactor based on the acetylene volume fraction at the inlet of the first-stage C2 hydrogenation reactor, the acetylene volume fraction at the outlet of the second-stage C2 hydrogenation reactor, and the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor.

[0076] If the acetylene hydrogenation conversion rate in the second-stage C2 hydrogenation reactor is not within the set range for the acetylene hydrogenation conversion rate in the second-stage C2 hydrogenation reactor, an alarm operation will be executed.

[0077] Step S203: Monitor the acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor, and gradually increase the inlet temperature of the third-stage C2 hydrogenation reactor at a preset heating rate until the acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor is within the preset three-stage acetylene volume fraction range. Then, stop increasing the inlet temperature of the third-stage C2 hydrogenation reactor. The three-stage acetylene volume fraction range is between (0, 1) ppm.

[0078] Step S204: When there is no acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor, calculate the inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor. If the inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor is greater than the temperature difference threshold, reduce the inlet temperature of the third-stage C2 hydrogenation reactor until the inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor is less than or equal to the temperature difference threshold.

[0079] In one embodiment, the temperature difference threshold is:

[0080]

[0081] Where △T is the temperature difference threshold, V 总 ΔH represents the molar flow rate of the feed to the third-stage C2 hydrogenation reactor. C2H2 The heat of hydrogenation of acetylene, ΔH MA The heat of hydrogenation of methylacetylene is ΔH. PD The heat of hydrogenation of propadiene, ΔH BD For the heat of hydrogenation of butadiene, F 总 M3 represents the mass flow rate of the feed to the third-stage C2 hydrogenation reactor, and Cp represents the mass of the third-stage C2 hydrogenation reactor. 总 To determine the specific heat capacity of the cracked gas entering the three-stage C2 hydrogenation reactor, C P3 Let X be the total specific heat capacity of the third-stage C2 hydrogenation reactor, k be the first temperature rise constant of the third-stage C2 hydrogenation reactor, l be the second temperature rise constant of the third-stage C2 hydrogenation reactor, m be the third temperature rise constant of the third-stage C2 hydrogenation reactor, a be the first heat coefficient of reaction of the third-stage C2 hydrogenation reactor, b be the second heat coefficient of reaction of the third-stage C2 hydrogenation reactor, c be the third heat coefficient of reaction of the third-stage C2 hydrogenation reactor, d be the fourth heat coefficient of reaction of the third-stage C2 hydrogenation reactor, and X be the... 3.C2H2X represents the acetylene content at the inlet of the third-stage C2 hydrogenation reactor. 3.MA X represents the methylacetylene content at the inlet of the third-stage C2 hydrogenation reactor. 3.PD X represents the propadiene content at the inlet of the third-stage C2 hydrogenation reactor. 3.BD This refers to the butadiene content at the inlet of the third-stage C2 hydrogenation reactor.

[0082] Specifically, such as Figure 3 The diagram shows a three-stage C2 hydrogenation reactor of the present invention, including a first-stage C2 hydrogenation reactor 1, a second-stage C2 hydrogenation reactor 2, and a third-stage C2 hydrogenation reactor 3. The initial feed temperature of the C2 hydrogenation reactors is lower than the starting temperature of the hydrogenation reaction, and the materials between each stage pass through a cooler process. The cracked gas enters the first-stage C2 hydrogenation reactor 1 through a heater 4, and after being cooled by a cooler 5, it enters the second-stage C2 hydrogenation reactor 2. Then, after being cooled by a cooler 6, it enters the third-stage C2 hydrogenation reactor 3, from which the product is output.

[0083] First, step S201 is executed, monitoring the volume fraction of the product emanating from the first-stage C2 hydrogenation reactor. The inlet temperature of the first-stage C2 hydrogenation reactor is gradually increased at a preset heating rate until the first-stage stopping heating condition is met, at which point the increase in the inlet temperature of the first-stage C2 hydrogenation reactor is stopped. The first-stage stopping heating condition is as follows:

[0084] After the ethylene volume fraction at the outlet of the first-stage C2 hydrogenation reactor begins to decrease, and the acetylene volume fraction is detectable at the outlet of the first-stage C2 hydrogenation reactor; or

[0085] After the volume fraction of ethane at the outlet of the first-stage C2 hydrogenation reactor begins to rise, and the volume fraction of acetylene at the outlet of the first-stage C2 hydrogenation reactor can be detected.

[0086] Specifically, the inlet temperature of the first-stage C2 hydrogenation reactor was gradually increased by 2℃ / h to obtain analytical data at the inlet and outlet of the first-stage C2 hydrogenation reactor, including the volume fractions of acetylene, ethylene, ethane, propylene, MAPD, and propane.

[0087] Once the ethylene volume fraction at the outlet of the first-stage C2 hydrogenation reactor begins to decrease and the acetylene volume fraction at the outlet of the first-stage C2 hydrogenation reactor becomes detectable, the temperature increase is stopped. At this point, the inlet temperature of the first-stage C2 hydrogenation reactor is T1; or

[0088] Once the ethane volume fraction at the outlet of the first-stage C2 hydrogenation reactor begins to rise and the acetylene volume fraction at the outlet of the first-stage reactor is detectable, the temperature increase is stopped. At this point, the inlet temperature of the first-stage C2 hydrogenation reactor is T1'.

[0089] Therefore, when the heating stop condition is met, the inlet temperature T of the first stage C2 hydrogenation reactor is...1入 =min(T1, T) 1` ).

[0090] This embodiment increases the selectivity of acetylene hydrogenation to ethylene, with a low reaction temperature, stable operation, and steam saving.

[0091] In one embodiment, controlling the inlet temperature of the first-stage C2 hydrogenation reactor based on the volume fraction of the product emanating from the first-stage C2 hydrogenation reactor further includes:

[0092] After stopping the increase in the inlet temperature of the first-stage C2 hydrogenation reactor, obtain the set range of acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor corresponding to the inlet temperature of the first-stage C2 hydrogenation reactor;

[0093] Calculate the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor based on the acetylene volume fraction at the inlet and outlet of the first-stage C2 hydrogenation reactor.

[0094] If the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor is not within the set range of the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor, an alarm operation will be executed.

[0095] Specifically, the inlet temperature T of the first-stage C2 hydrogenation reactor is obtained. 1入 Below is the acetylene volume fraction at the outlet of the first-stage C2 hydrogenation reactor. Based on its hydrogenation reaction characteristics, the conversion rate is determined. Since the reaction temperature and conversion rate are basically correlated, the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor can be adjusted by controlling the inlet temperature of the first-stage C2 hydrogenation reactor, thereby keeping the difference in acetylene volume content between the inlet and outlet of the first-stage C2 hydrogenation reactor within a preset range.

[0096] Different inlet temperatures of the first-stage C2 hydrogenation reactor correspond to a specific acetylene hydrogenation conversion rate. This acetylene hydrogenation conversion rate ± error value represents the set range for the acetylene hydrogenation conversion rate corresponding to the inlet temperature of that first-stage C2 hydrogenation reactor. During normal operation, the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor is within the set range corresponding to its inlet temperature. If the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor is outside this set range, a fault occurs, and an alarm is triggered.

[0097] In some embodiments, calculating the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor based on the acetylene volume fraction at the inlet and outlet of the first-stage C2 hydrogenation reactor includes:

[0098] The acetylene hydrogenation conversion rate in the first stage C2 hydrogenation reactor is calculated as follows:

[0099] Y1=(XX 1出 ) / X;

[0100] Where Y1 is the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor, and X is the acetylene volume fraction at the inlet of the first-stage C2 hydrogenation reactor. 1出 This represents the volume fraction of acetylene at the outlet of the first-stage C2 hydrogenation reactor.

[0101] Preferably, 0.2% ≤ X ≤ 1%, 0.3X ≤ X 1出 ≤0.6X.

[0102] This embodiment determines whether the first-stage C2 hydrogenation reactor is malfunctioning by monitoring the acetylene hydrogenation conversion rate in the first-stage C2 hydrogenation reactor.

[0103] Then, step S202 is executed, monitoring the volume fraction of the product emanating from the second-stage C2 hydrogenation reactor. The inlet temperature of the second-stage C2 hydrogenation reactor is gradually increased at a preset heating rate until the second-stage heating stop condition is met, at which point the increase in the inlet temperature of the second-stage C2 hydrogenation reactor is stopped. The second-stage heating stop condition is as follows:

[0104] After the ethylene volume fraction at the outlet of the second-stage C2 hydrogenation reactor begins to decrease, and the acetylene volume fraction is detectable at the outlet of the second-stage C2 hydrogenation reactor; or

[0105] After the volume fraction of ethane at the outlet of the second-stage C2 hydrogenation reactor begins to rise, and the volume fraction of acetylene at the outlet of the second-stage reactor's C2 hydrogenation reactor becomes detectable.

[0106] Specifically, the inlet temperature of the second-stage C2 hydrogenation reactor was gradually increased by 2℃ / h to obtain analytical data at the inlet and outlet of the second-stage C2 hydrogenation reactor, including the volume fractions of acetylene, ethylene, ethane, propylene, MAPD, and propane.

[0107] Once the ethylene volume fraction at the outlet of the second-stage C2 hydrogenation reactor begins to decrease and the acetylene volume fraction at the outlet of the second-stage C2 hydrogenation reactor becomes detectable, the temperature increase is stopped. At this point, the inlet temperature of the second-stage C2 hydrogenation reactor is T2; or

[0108] Once the ethane volume fraction at the outlet of the second-stage C2 hydrogenation reactor begins to rise and the acetylene volume fraction at the outlet of the second-stage reactor is detectable, the temperature increase is stopped. At this point, the inlet temperature of the second-stage C2 hydrogenation reactor is T2'.

[0109] Therefore, when the first stage of the heating stop condition is met, the inlet temperature T of the second stage C2 hydrogenation reactor is... 2入 =min(T2, T2`).

[0110] This embodiment further increases the selectivity of acetylene hydrogenation to ethylene, with a low reaction temperature, stable operation, and steam saving.

[0111] In one embodiment, controlling the inlet temperature of the second-stage C2 hydrogenation reactor based on the volume fraction of the product exiting the second-stage C2 hydrogenation reactor further includes:

[0112] After stopping the increase in the inlet temperature of the second-stage C2 hydrogenation reactor, obtain the set range of acetylene hydrogenation conversion rate of the second-stage C2 hydrogenation reactor corresponding to the inlet temperature of the second-stage C2 hydrogenation reactor;

[0113] Calculate the acetylene hydrogenation conversion rate of the second-stage C2 hydrogenation reactor based on the acetylene volume fraction at the inlet of the first-stage C2 hydrogenation reactor, the acetylene volume fraction at the outlet of the second-stage C2 hydrogenation reactor, and the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor.

[0114] If the acetylene hydrogenation conversion rate in the second-stage C2 hydrogenation reactor is not within the set range for the acetylene hydrogenation conversion rate in the second-stage C2 hydrogenation reactor, an alarm operation will be executed.

[0115] Specifically, the inlet temperature T of the second-stage C2 hydrogenation reactor is obtained. 2入 The acetylene volume fraction at the outlet of the second-stage C2 hydrogenation reactor can be adjusted by controlling the inlet temperature of the second-stage C2 hydrogenation reactor, thereby keeping the difference in acetylene volume content between the inlet and outlet of the second-stage bed C2 hydrogenation reactor within a preset range.

[0116] Different inlet temperatures of the second-stage C2 hydrogenation reactor correspond to a specific acetylene hydrogenation conversion rate. This acetylene hydrogenation conversion rate ± error value represents the set range for the acetylene hydrogenation conversion rate corresponding to the inlet temperature of that second-stage C2 hydrogenation reactor. During normal operation, the acetylene hydrogenation conversion rate of the second-stage C2 hydrogenation reactor is within the set range corresponding to the inlet temperature. If the acetylene hydrogenation conversion rate of the second-stage C2 hydrogenation reactor is outside this set range, a fault occurs, and an alarm is triggered.

[0117] In some embodiments, calculating the acetylene hydrogenation conversion rate of the second-stage C2 hydrogenation reactor based on the acetylene volume fraction at the inlet and outlet of the second-stage C2 hydrogenation reactor includes:

[0118] The acetylene hydrogenation conversion rate in the second-stage C2 hydrogenation reactor is calculated as follows:

[0119] Y2=((1-Y1)XX 2出 ) / X;

[0120] Where Y2 is the acetylene hydrogenation conversion rate in the second-stage C2 hydrogenation reactor, Y1 is the acetylene hydrogenation conversion rate in the first-stage C2 hydrogenation reactor, and X is the acetylene volume fraction at the inlet of the first-stage C2 hydrogenation reactor. 2出 This represents the volume fraction of acetylene at the outlet of the second-stage C2 hydrogenation reactor.

[0121] Preferably, 0.2% ≤ X ≤ 1%, 0.05X ≤ X 2出 ≤0.1X.

[0122] Optional analysis data includes:

[0123] The inlet material temperature, inlet material pressure, inlet material flow rate, inlet acetylene volume fraction, and outlet acetylene volume fraction of the first and second stage C2 hydrogenation reactors.

[0124] This embodiment determines whether the second-stage C2 hydrogenation reactor is malfunctioning by monitoring the acetylene hydrogenation conversion rate in the second-stage C2 hydrogenation reactor.

[0125] Then, step S203 is executed, monitoring the acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor. The inlet temperature of the third-stage C2 hydrogenation reactor is gradually increased at a preset heating rate until the acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor is within a preset range of three-stage acetylene volume fractions. At this point, the increase in the inlet temperature of the third-stage C2 hydrogenation reactor is stopped. The range of three-stage acetylene volume fractions is between (0, 1) ppm. Wherein ppm is parts per million (ppm).

[0126] Specifically, when the inlet temperature of the third-stage C2 hydrogenation reactor increases, the acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor gradually decreases. When the acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor decreases to within the preset range of the three-stage acetylene volume fraction, the increase in the inlet temperature of the third-stage C2 hydrogenation reactor is stopped.

[0127] In some embodiments, the preset third acetylene volume fraction range is (0 to 0.5) ppm.

[0128] Specifically, the inlet temperature of the third-stage C2 hydrogenation reactor was gradually increased by 2℃ / h to obtain analytical data at the inlet and outlet of the third-stage C2 hydrogenation reactor, including the volume fractions of acetylene, ethylene, ethane, propylene, MAPD, and propane.

[0129] When the acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor is less than 0.5 ppm, the increase in the inlet temperature T3 of the third-stage C2 hydrogenation reactor is stopped. At this time, the outlet temperature of the third-stage C2 hydrogenation reactor is T. 3出 That is, when the acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor is (0–0.5) ppm, the inlet temperature T of the third-stage C2 hydrogenation reactor is...3入 It is T3.

[0130] Then, the acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor is monitored. When there is no acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor, step S204 is executed to calculate the inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor. If the inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor is greater than the temperature difference threshold, the inlet temperature of the third-stage C2 hydrogenation reactor is reduced until the inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor is less than or equal to the temperature difference threshold.

[0131] Specifically, the volume fraction of acetylene at the outlet of the third-stage C2 hydrogenation reactor will gradually decrease. When there is no volume fraction of acetylene at the outlet of the third-stage C2 hydrogenation reactor, the inlet temperature of the third-stage C2 hydrogenation reactor will be adjusted according to the temperature difference between the inlet and outlet of the third-stage C2 hydrogenation reactor.

[0132] The inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor is the outlet temperature of the third-stage C2 hydrogenation reactor minus the inlet temperature of the third-stage C2 hydrogenation reactor, i.e., T. 3出 -T3.

[0133] When T 3出 When -T3>ΔT, the inlet temperature of the three-stage C2 hydrogenation reactor is reduced to the temperature difference threshold ΔT.

[0134] When the acetylene volume fraction at the outlet of the three-stage C2 hydrogenation reactor is (0–0.5) ppm, it is not necessary to calculate the inlet and outlet temperature difference of the three-stage C2 hydrogenation reactor.

[0135] This embodiment reduces the over-hydrogenation of acetylene to ethane and the hydrogenation of ethylene to ethane by lowering the inlet temperature of the third-stage C2 hydrogenation reactor to a temperature difference threshold less than or equal to the inlet temperature difference threshold, thereby increasing the ethylene yield.

[0136] In one embodiment, the temperature difference threshold is:

[0137]

[0138] Where △T is the temperature difference threshold, V 总 ΔH represents the molar flow rate of the feed to the third-stage C2 hydrogenation reactor. C2H2 The heat of hydrogenation of acetylene, ΔH MA The heat of hydrogenation of methylacetylene is ΔH. PD The heat of hydrogenation of propadiene, ΔH BD For the heat of hydrogenation of butadiene, F 总 M3 represents the mass flow rate of the feed to the third-stage C2 hydrogenation reactor, and Cp represents the mass of the third-stage C2 hydrogenation reactor. 总To determine the specific heat capacity of the cracked gas entering the three-stage C2 hydrogenation reactor, C P3 Let X be the total specific heat capacity of the third-stage C2 hydrogenation reactor, k be the first temperature rise constant of the third-stage C2 hydrogenation reactor, l be the second temperature rise constant of the third-stage C2 hydrogenation reactor, m be the third temperature rise constant of the third-stage C2 hydrogenation reactor, a be the first heat coefficient of reaction of the third-stage C2 hydrogenation reactor, b be the second heat coefficient of reaction of the third-stage C2 hydrogenation reactor, c be the third heat coefficient of reaction of the third-stage C2 hydrogenation reactor, d be the fourth heat coefficient of reaction of the third-stage C2 hydrogenation reactor, and X be the... 3.C2H2 X represents the acetylene content at the inlet of the third-stage C2 hydrogenation reactor. 3.MA X represents the methylacetylene content at the inlet of the third-stage C2 hydrogenation reactor. 3.PD X represents the propadiene content at the inlet of the third-stage C2 hydrogenation reactor. 3.BD This refers to the butadiene content at the inlet of the third-stage C2 hydrogenation reactor.

[0139] Preferably, the inlet temperature of each section of the C2 hydrogenation reactor is adjusted within the range of 35-80℃, and more preferably 45-70℃.

[0140] No hydrogenation modifier is required in any of the C2 hydrogenation reactors.

[0141] The hydrogen-to-acetylene ratio cannot be adjusted in any of the C2 hydrogenation reactors, resulting in all reactors being over-hydrogenated.

[0142] The inlet material temperature adjustment rate for each stage of the C2 hydrogenation reactor is 0.5-10℃ / h, preferably 2-4℃ / h.

[0143] The inlet materials for each section of the C2 hydrogenation reactor include at least hydrogen, methane, carbon monoxide, acetylene, ethylene, ethane, MA, PD, propylene, and propane.

[0144] The volume fraction of acetylene in the inlet feed of the first-stage C2 hydrogenation reactor is between 0.2% and 1%.

[0145] This embodiment, based on the analysis data changes at the inlet and outlet of each stage of the C2 hydrogenation reactor, combined with the hydrogenation reaction rates and heats of reaction of carbon monoxide, acetylene, MA, PD, and ethylene, adjusts the operating conditions of each stage of the hydrogenation reactor. This allows for the rational allocation and setting of the load on each stage of the C2 hydrogenation reactor, solving the problem of ethylene loss caused by over-hydrogenation in the three-stage pre-hydrogenation C2 hydrogenation reactor. This increases the stability of ethylene production, lowers the reaction temperature compared to traditional methods, reduces the risk of temperature runaway, and improves the selectivity and operational stability of the C2 hydrogenation reactor. At the same time, the lower reaction temperature reduces steam consumption and lowers the steam usage of the reactor.

[0146] The following example illustrates a control method for a three-stage C2 hydrogenation reactor according to an embodiment of the present invention. The reactor feed used in the following examples is cracked gas with a CO content of 200 ppm, and the catalyst used is a Pd-based catalyst from PHILLIPS.

[0147] Example 1

[0148] The feed to the C2 hydrogenation reactor contained 0.28% acetylene, 28.41% ethylene, 4.58% ethane, and 200 ppm CO. The inlet temperature of the first-stage C2 hydrogenation reactor was increased at a rate of 2℃ / h, with a temperature control range of 50℃-65℃. Analytical data, including the volume fractions of acetylene, ethylene, ethane, propylene, MAPD, and propane, were obtained at the inlet and outlet of the reactor. Within the temperature control range, the ethylene volume fraction in the cracked gas at the outlet of the first-stage C2 hydrogenation reactor was higher than that at the inlet, eliminating the risk of over-hydrogenation. When the feed temperature exceeded 55℃, the ethylene volume fraction at the reactor outlet decreased. The temperature was controlled at approximately 55℃. At this feed temperature, an acetylene volume fraction of 900 ppm at the reactor outlet was optimal. When the feed temperature of the C2 hydrogenation reactor exceeds 58°C, the volume fraction of ethane at the reactor outlet increases. When the temperature is controlled at around 58°C, the volume fraction of acetylene at the reactor outlet is approximately 600 ppm.

[0149] Optionally, the inlet temperature T of the first-stage C2 hydrogenation reactor 1入 =min(T1, T1`), the inlet temperature is 55℃, the outlet acetylene volume fraction is 900ppm, and the hydrogenation distribution load of the first stage C2 hydrogenation reactor, i.e., the acetylene hydrogenation conversion rate, is 70%.

[0150] Under these operating conditions, at this inlet temperature, the ethylene selectivity of the first-stage C2 hydrogenation reactor is 95%, which is higher than that of other inlet temperatures.

[0151] Example 2

[0152] The feed to the C2 hydrogenation reactor contained 0.09% acetylene, 28.60% ethylene, 4.60% ethane, and 200 ppm CO. The inlet temperature of the second-stage C2 hydrogenation reactor was increased at a rate of 2℃ / h, with a temperature control range of 50℃-70℃. Analytical data, including the volume fractions of acetylene, ethylene, ethane, propylene, MAPD, and propane, were obtained at the inlet and outlet of the C2 hydrogenation reactor. Within the temperature control range, when the inlet temperature of the C2 hydrogenation reactor exceeded 63℃, the ethylene volume fraction was lower than the inlet temperature, posing a risk of over-hydrogenation. When the feed temperature of the C2 hydrogenation reactor exceeded 60℃, the ethylene volume fraction at the outlet of the second-stage C2 hydrogenation reactor decreased. At this feed temperature, an acetylene volume fraction of approximately 100 ppm at the outlet of the C2 hydrogenation reactor was optimal. When the feed temperature of the C2 hydrogenation reactor exceeded 61℃, the ethane volume fraction at the outlet of the C2 hydrogenation reactor increased. With the temperature controlled at approximately 61℃, the acetylene volume fraction at the outlet of the C2 hydrogenation reactor was approximately 50 ppm.

[0153] Optionally, the inlet temperature T of the second-stage C2 hydrogenation reactor 2入 =min(T2, T2`), the inlet temperature is 60℃, the outlet acetylene volume fraction is 130ppm, and the hydrogenation distribution load of the first stage C2 hydrogenation reactor is 25%.

[0154] Under these operating conditions, at this inlet temperature, the ethylene selectivity of the second-stage C2 hydrogenation reactor is 95%, which is higher than at other inlet temperatures.

[0155] Example 3

[0156] The feed to the third-stage C2 hydrogenation reactor contained 0.01% acetylene, 28.64% ethylene, 4.65% ethane, and 200 ppm CO. The inlet temperature of the C2 hydrogenation reactor was increased at a rate of 2℃ / h, with a temperature control range of 50℃-70℃. Analytical data were obtained at the inlet and outlet of the C2 hydrogenation reactor, including the volume fractions of acetylene, ethylene, ethane, propylene, MAPD, and propane. Within the temperature control range, at an inlet temperature of 62℃, the acetylene volume fraction at the outlet was (0-0.5) ppm, meeting the hydrogenation target. The ethylene selectivity of the third-stage C2 hydrogenation reactor was 80%. Further increasing the inlet temperature resulted in an acetylene volume fraction of 0% at the outlet, a decrease in the ethylene volume fraction, and a decline in the ethylene selectivity. At this point, the temperature rise of the C2 hydrogenation reactor was 2.3℃.

[0157] The hydrogenation temperature difference threshold when there is no acetylene at the outlet is:

[0158]

[0159] Where △T is the temperature difference threshold, V 总ΔH represents the molar flow rate of the feed to the third-stage C2 hydrogenation reactor. C2H2 The heat of hydrogenation of acetylene, ΔH MA The heat of hydrogenation of methylacetylene is ΔH. PD The heat of hydrogenation of propadiene, ΔH BD For the heat of hydrogenation of butadiene, F 总 M3 represents the mass flow rate of the feed to the third-stage C2 hydrogenation reactor, and Cp represents the mass of the third-stage C2 hydrogenation reactor. 总 To determine the specific heat capacity of the cracked gas entering the three-stage C2 hydrogenation reactor, C P3 Let X be the total specific heat capacity of the third-stage C2 hydrogenation reactor, k be the first temperature rise constant of the third-stage C2 hydrogenation reactor, l be the second temperature rise constant of the third-stage C2 hydrogenation reactor, m be the third temperature rise constant of the third-stage C2 hydrogenation reactor, a be the first heat coefficient of reaction of the third-stage C2 hydrogenation reactor, b be the second heat coefficient of reaction of the third-stage C2 hydrogenation reactor, c be the third heat coefficient of reaction of the third-stage C2 hydrogenation reactor, d be the fourth heat coefficient of reaction of the third-stage C2 hydrogenation reactor, and X be the... 3.C2H2 X represents the acetylene content at the inlet of the third-stage C2 hydrogenation reactor. 3.MA X represents the methylacetylene content at the inlet of the third-stage C2 hydrogenation reactor. 3.PD X represents the propadiene content at the inlet of the third-stage C2 hydrogenation reactor. 3.BD This refers to the butadiene content at the inlet of the third-stage C2 hydrogenation reactor.

[0160] Analytical data was obtained from the inlet of the C2 hydrogenation reactor, including the volume fractions of acetylene, ethylene, ethane, propylene, MAPD, and propane. The highest temperature rise without over-hydrogenation was 1.9°C. "No over-hydrogenation" indicates that no acetylene or ethylene was hydrogenated to produce ethane.

[0161] T3 出 -T3>ΔT, reduce the inlet temperature of the third-stage C2 hydrogenation reactor to ΔT, the inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor is 74%, and the ethylene selectivity of the third-stage C2 hydrogenation reactor is 74%.

[0162] When the acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor is (0–0.5) ppm, the inlet temperature T3 of the third-stage C2 hydrogenation reactor... 入 Based on T3.

[0163] Example 4

[0164] A 1 million-ton-per-year ethylene plant has six cracking furnaces, primarily using propane as the cracking feedstock. It employs a pre-propane removal and pre-hydrogenation process, with the C2 hydrogenation reactor located before the pre-cooler. It utilizes excess hydrogen from the feed without separate hydrogen supply and uses a three-stage reactor series design. Each reactor is adiabatic. The inlet temperature of the first-stage reactor is increased by steam heating, while circulating water cooling is used between stages to control the inlet temperature of each C2 hydrogenation reactor. The catalyst is a Pd-based catalyst from PHILLIPS. During operation of the C2 hydrogenation reactors, the distributed control system (DCS) is connected to an online chromatograph. Online chromatographic analysis data can be directly input into the DCS to obtain the inlet and outlet component analysis data of each C2 hydrogenation reactor stage.

[0165] The feed to the C2 hydrogenation reactor contained 0.28% acetylene, 28.41% ethylene, 4.58% ethane, and 200 ppm CO. The control methods described in Examples 1, 2, and 3 were used to control the first, second, and third stages of the C2 hydrogenation reactor. Y1 = 70%, X... 1出 =900ppm, Y2=25%, X 2出 =130ppm, Y3=5%, X 3出 = (0~0.5)ppm, ΔT3 = 1.9℃. This control method can control the inlet material temperature of each stage of the C2 hydrogenation reactor, avoiding full-load acetylene hydrogenation in the first stage C2 hydrogenation reactor and excessive hydrogenation in the second and third stage C2 hydrogenation reactors, which would cause ethylene to hydrogenate into ethane and result in ethylene loss. The selectivity of this three-stage C2 hydrogenation reactor is increased to 90%, and the steam consumption is reduced by 30%.

[0166] Comparative Example

[0167] This comparative example uses the same process, C2 hydrogenation reactor, and catalyst as Example 4. The feed contains 0.28% acetylene, 28.41% ethylene, 4.58% ethane, and 200 ppm CO. However, the control method of Example 4 was not used, resulting in the first-stage C2 hydrogenation reactor being fully loaded with acetylene hydrogenation, and the second and third-stage C2 hydrogenation reactors being overloaded with hydrogen. Y1 = 95%, X... 1出 =100ppm, Y2=5%, X 2出 =0ppm, Y3=0, X 3出 =0ppm, ΔT3=3℃. Although the acetylene content at the outlet of the C2 hydrogenation reactor is 0, which meets the product index requirements, some ethylene is hydrogenated to ethane, resulting in ethylene loss. The selectivity of the third-stage C2 hydrogenation reactor is only 45%, and the steam consumption at the inlet of the first-stage reactor has increased.

[0168] The comparative results show that the control method of this embodiment can significantly improve the selectivity of the C2 hydrogenation reactor in the pre-propane dehydrogenation process.

[0169] like Figure 4 The diagram shown is a hardware structure schematic of an electronic device according to the present invention, comprising:

[0170] At least one processor 401; and,

[0171] A memory 402 is communicatively connected to at least one of the processors 401; wherein,

[0172] The memory 402 stores instructions that can be executed by at least one of the processors to enable the at least one processor to perform the control method for the three-stage C2 hydrogenation reactor as described above.

[0173] Figure 4 Take a processor 401 as an example.

[0174] The electronic device may also include an input device 403 and a display device 404.

[0175] The processor 401, memory 402, input device 403 and display device 404 can be connected by a bus or other means. The figure shows an example of connection by bus.

[0176] Memory 402, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules, such as the program instructions / modules corresponding to the control method of the three-stage C2 hydrogenation reactor in the embodiments of this application. Figure 1 , Figure 2 The method flow is shown. The processor 401 executes various functional applications and data processing by running non-volatile software programs, instructions, and modules stored in the memory 402, thereby realizing the control method of the three-stage C2 hydrogenation reactor in the above embodiment.

[0177] The memory 402 may include a program storage area and a data storage area. The program storage area may store an operating system and an application program required for at least one function. The data storage area may store data created based on the use of the control method for the three-stage C2 hydrogenation reactor. Furthermore, the memory 402 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 402 may optionally include memory remotely located relative to the processor 401, and these remote memories may be connected via a network to the apparatus executing the control method for the three-stage C2 hydrogenation reactor. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0178] Input device 403 can receive user clicks and generate signal inputs related to user settings and function control of the three-stage C2 hydrogenation reactor. Display device 404 may include display screens or other display devices.

[0179] When one or more modules are stored in the memory 402 and are run by one or more processors 401, the control method of the three-stage C2 hydrogenation reactor in any of the above method embodiments is executed.

[0180] This invention adjusts the operating conditions of each stage of the C2 hydrogenation reactor based on the changes in the inlet and outlet data of each stage. This allows for a reasonable distribution and setting of the load on each stage of the C2 hydrogenation reactor, solving the problem of ethylene loss caused by over-hydrogenation in the three-stage pre-hydrogenation C2 hydrogenation reactor. This results in increased and more stable ethylene production, a lower reaction temperature than traditional methods, and reduced risk of temperature runaway. It also improves the selectivity and operational stability of the C2 hydrogenation reactor. Furthermore, the lower reaction temperature reduces steam consumption and lowers the overall steam consumption of the reactor.

[0181] One embodiment of the present invention provides a storage medium that stores computer instructions, which, when executed by a computer, are used to perform all steps of the control method for the three-stage C2 hydrogenation reactor as described above.

[0182] One embodiment of the present invention provides a method for refining ethylene by hydrogenation of acetylene, which is applied to the hydrogenation process before an ethylene plant. The method for controlling the three-stage C2 hydrogenation reactor in the C2 hydrogenation system of the hydrogenation process before the ethylene plant is as described above.

[0183] Specifically, the ethylene refining hydrogenation and acetylene removal method of this embodiment is applied to the hydrogenation process before the ethylene unit, mainly including the hydrogenation process before ethane removal and the hydrogenation process before propane removal. It utilizes the hydrogen contained in the material itself, eliminating the need for additional hydrogen supply to the hydrogenation reactor, thus reducing the difficulty of operation. The control method of the three-stage C2 hydrogenation reactor as described above is used in the C2 hydrogenation system of the hydrogenation process before the ethylene unit.

[0184] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A control method for a three-stage C2 hydrogenation reactor, wherein the three-stage C2 hydrogenation reactor comprises a first-stage C2 hydrogenation reactor, a second-stage C2 hydrogenation reactor, and a third-stage C2 hydrogenation reactor connected in series, characterized in that, The method includes: Monitor the volume fraction of the product effluent from the first-stage C2 hydrogenation reactor, and control the inlet temperature of the first-stage C2 hydrogenation reactor based on the volume fraction of the product effluent from the first-stage C2 hydrogenation reactor. Monitor the volume fraction of the product effluent from the second-stage C2 hydrogenation reactor, and control the inlet temperature of the second-stage C2 hydrogenation reactor based on the volume fraction of the product effluent from the second-stage C2 hydrogenation reactor. Monitor the volume fraction of acetylene at the outlet of the third-stage C2 hydrogenation reactor, and control the inlet temperature of the third-stage C2 hydrogenation reactor based on the volume fraction of the product at the outlet of the third-stage C2 hydrogenation reactor. The method of controlling the inlet temperature of the third-stage C2 hydrogenation reactor based on the volume fraction of the effluent from the third-stage C2 hydrogenation reactor includes: The inlet temperature of the third-stage C2 hydrogenation reactor is gradually increased at a preset heating rate until the acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor is within the preset three-stage acetylene volume fraction range. Then, the increase in the inlet temperature of the third-stage C2 hydrogenation reactor is stopped. The three-stage acetylene volume fraction range is between (0, 1) ppm. When there is no acetylene volume fraction at the outlet of the third-stage C2 hydrogenation reactor, the inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor is calculated. If the inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor is greater than the temperature difference threshold, the inlet temperature of the third-stage C2 hydrogenation reactor is reduced until the inlet and outlet temperature difference of the third-stage C2 hydrogenation reactor is less than or equal to the temperature difference threshold.

2. The control method for the three-stage C2 hydrogenation reactor according to claim 1, characterized in that, The method of controlling the inlet temperature of the first-stage C2 hydrogenation reactor based on the volume fraction of the effluent from the first-stage C2 hydrogenation reactor includes: The inlet temperature of the first-stage C2 hydrogenation reactor is gradually increased at a preset heating rate until the first-stage stopping heating condition is met. Then, the increase in the inlet temperature of the first-stage C2 hydrogenation reactor is stopped. The first-stage stopping heating condition is as follows: After the ethylene volume fraction at the outlet of the first-stage C2 hydrogenation reactor begins to decrease, and the acetylene volume fraction is detectable at the outlet of the first-stage C2 hydrogenation reactor; or After the volume fraction of ethane at the outlet of the first-stage C2 hydrogenation reactor begins to rise, and the volume fraction of acetylene at the outlet of the first-stage C2 hydrogenation reactor becomes detectable.

3. The control method for the three-stage C2 hydrogenation reactor according to claim 2, characterized in that, The method of controlling the inlet temperature of the first-stage C2 hydrogenation reactor based on the volume fraction of the effluent from the first-stage C2 hydrogenation reactor further includes: After stopping the increase in the inlet temperature of the first-stage C2 hydrogenation reactor, obtain the set range of acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor corresponding to the inlet temperature of the first-stage C2 hydrogenation reactor; Calculate the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor based on the acetylene volume fraction at the inlet and outlet of the first-stage C2 hydrogenation reactor. If the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor is not within the set range of the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor, an alarm operation will be executed.

4. The control method for the three-stage C2 hydrogenation reactor according to claim 1, characterized in that, The method of controlling the inlet temperature of the second-stage C2 hydrogenation reactor based on the volume fraction of the effluent from the second-stage C2 hydrogenation reactor includes: The inlet temperature of the second-stage C2 hydrogenation reactor is gradually increased at a preset heating rate until the second-stage heating stop condition is met. Then, the increase in the inlet temperature of the second-stage C2 hydrogenation reactor is stopped. The second-stage heating stop condition is as follows: After the ethylene volume fraction at the outlet of the second-stage C2 hydrogenation reactor begins to decrease, and the acetylene volume fraction is detectable at the outlet of the second-stage C2 hydrogenation reactor; or After the volume fraction of ethane at the outlet of the second-stage C2 hydrogenation reactor begins to rise, and the volume fraction of acetylene at the outlet of the second-stage reactor's C2 hydrogenation reactor becomes detectable.

5. The control method for the three-stage C2 hydrogenation reactor according to claim 4, characterized in that, The method of controlling the inlet temperature of the second-stage C2 hydrogenation reactor based on the volume fraction of the effluent from the second-stage C2 hydrogenation reactor further includes: After stopping the increase in the inlet temperature of the second-stage C2 hydrogenation reactor, obtain the set range of acetylene hydrogenation conversion rate of the second-stage C2 hydrogenation reactor corresponding to the inlet temperature of the second-stage C2 hydrogenation reactor; Calculate the acetylene hydrogenation conversion rate of the second-stage C2 hydrogenation reactor based on the acetylene volume fraction at the inlet of the first-stage C2 hydrogenation reactor, the acetylene volume fraction at the outlet of the second-stage C2 hydrogenation reactor, and the acetylene hydrogenation conversion rate of the first-stage C2 hydrogenation reactor. If the acetylene hydrogenation conversion rate in the second-stage C2 hydrogenation reactor is not within the set range for the acetylene hydrogenation conversion rate in the second-stage C2 hydrogenation reactor, an alarm operation will be executed.

6. The control method for the three-stage C2 hydrogenation reactor according to claim 1, characterized in that, The temperature difference threshold is: ； Where △T is the temperature difference threshold, V 总 ΔH represents the molar flow rate of the feed to the third-stage C2 hydrogenation reactor. C2H2 The heat of hydrogenation of acetylene, ΔH MA The heat of hydrogenation of methylacetylene is ΔH. PD The heat of hydrogenation of propadiene, ΔH BD For the heat of hydrogenation of butadiene, F 总 M3 represents the mass flow rate of the feed to the third-stage C2 hydrogenation reactor, and Cp represents the mass of the third-stage C2 hydrogenation reactor. 总 To determine the specific heat capacity of the cracked gas entering the three-stage C2 hydrogenation reactor, C P3 Let X be the total specific heat capacity of the third-stage C2 hydrogenation reactor, k be the first temperature rise constant of the third-stage C2 hydrogenation reactor, l be the second temperature rise constant of the third-stage C2 hydrogenation reactor, m be the third temperature rise constant of the third-stage C2 hydrogenation reactor, a be the first heat coefficient of reaction of the third-stage C2 hydrogenation reactor, b be the second heat coefficient of reaction of the third-stage C2 hydrogenation reactor, c be the third heat coefficient of reaction of the third-stage C2 hydrogenation reactor, d be the fourth heat coefficient of reaction of the third-stage C2 hydrogenation reactor, and X be the... 3.C2H2 X represents the acetylene content at the inlet of the third-stage C2 hydrogenation reactor. 3.MA X represents the methylacetylene content at the inlet of the third-stage C2 hydrogenation reactor. 3.PD X represents the propadiene content at the inlet of the third-stage C2 hydrogenation reactor. 3.BD This refers to the butadiene content at the inlet of the third-stage C2 hydrogenation reactor.

7. An electronic device, characterized in that, include: At least one processor; as well as, A memory communicatively connected to at least one of the processors; wherein, The memory stores instructions executable by at least one of the processors, which enable the at least one processor to perform the control method for the three-stage C2 hydrogenation reactor as described in any one of claims 1 to 6.

8. A storage medium, characterized in that, The storage medium stores computer instructions, which, when executed by the computer, are used to perform all steps of the control method for the three-stage C2 hydrogenation reactor as described in any one of claims 1 to 6.

9. A method for refining ethylene by hydrogenation of acetylene, applied to the hydrogenation process before an ethylene plant, characterized in that, The control method of the three-stage C2 hydrogenation reactor as described in any one of claims 1 to 6 is adopted in the C2 hydrogenation system of the hydrogenation process before the ethylene unit.

Images