Process and plant for the production of methane chlorides with selective product regulation

Abstract

The application discloses a product selective adjustable methane chloride production process and device. The product selective adjustable methane chloride production process adjusts target product composition by changing the form of chlorine gas feed into gas, liquid or gas-liquid mixed state. The product selective adjustable methane chloride production device comprises a chlorine gas inlet which can switch each other in the form of gas, liquid or gas-liquid mixed state. The application can flexibly regulate and control the selectivity of product dichloromethane, chloroform and carbon tetrachloride according to different feed states, and flexibly adapt to market changes.

Description

Technical Field

[0001] This invention relates to the field of methane chloride production technology, specifically to a methane chloride production process and apparatus with adjustable product selectivity. Background Technology

[0002] Methane chloride, as a crucial basic chemical raw material, involves various processes such as thermal chlorination and liquid-phase chlorination in its production. The core reaction is the stepwise chlorination reaction between chlorine and chloromethane. The products, dichloromethane, trichloromethane, and carbon tetrachloride, are obtained through separation. However, current production technologies generally face challenges such as high energy consumption, large-scale generation of byproducts (such as carbon tetrachloride), inability of dichloromethane and trichloromethane selectivity to adapt to changing market demands, and excessively complex system structures.

[0003] The downstream products of dichloromethane and trichloromethane are mostly fine chemicals, with a wide variety but relatively low individual outputs. Therefore, market demand for dichloromethane and trichloromethane is highly variable. Currently, without significant modifications, the proportion of these two compounds in the product mix cannot be drastically adjusted.

[0004] In chlorination reaction feed design, current mainstream designs primarily use gaseous chlorine feed, such as CN204583128U (reactor for the liquid-phase preparation of methane chloride) and CN104785170A (reactor and method), both of which employ gaseous chlorine feed distributors. By promoting the uniform distribution of gaseous chlorine and chloromethane, they effectively improve reaction efficiency. However, this technical approach also has significant drawbacks. Obtaining gaseous chlorine requires vaporization equipment such as evaporators to convert liquid chlorine into a gaseous state. The latent heat of vaporization in this process is approximately 280 kJ / kg, leading to a substantial increase in energy consumption. Furthermore, to effectively remove the heat generated by the reaction, complex heat transfer structures such as serpentine coils are typically required in the reactor (e.g., CN204583128U and CN104785170A), which not only complicates the equipment structure but also significantly increases the heat transfer load.

[0005] Among the products, carbon tetrachloride has the highest chlorine consumption but the lowest value, making it a byproduct that methane chlorination units often aim to reduce. Patent CN115850014B (Energy-Saving Refining Process) reduces carbon tetrachloride production to some extent through optimization of the distillation process; however, it unfortunately does not address the suppression of side reactions during the reaction stage. In existing processes, both domestic and international technologies use separate feeds for chlorine and chloromethane (e.g., in CN204583128U, gaseous chlorine and chloromethane are fed through different distributors). This feeding method easily leads to uneven local reactant concentrations, thus exacerbating side reactions. For example, in the CN104785170A technology, the selectivity for carbon tetrachloride is as high as 8%, requiring additional processing steps (such as a process for preparing chloromethane from carbon tetrachloride), undoubtedly increasing production costs.

[0006] After obtaining the crude product, residual hydrogen chloride needs to be removed to reduce corrosion of subsequent distillation equipment. Currently, the mainstream approach still involves neutralizing the residual hydrogen chloride with alkali (e.g., in CN110183304A, the acidity reaches 200 ppm). This not only leads to redundant setups in equipment such as azeotropic dehydration towers and regeneration units, increasing equipment costs, but also results in high wastewater treatment costs. Patent CN110183304A (energy-saving alkali washing process) uses low-concentration alkali to reduce the decomposition of methane chloride, but this does not fundamentally address the core requirements of the alkali washing process. Summary of the Invention

[0007] Firstly, this invention provides a methane chloride production process with adjustable product selectivity, which adjusts the target product composition by changing the chlorine feed form to gas, liquid, or a gas-liquid mixture. Liquid chlorine feed reduces carbon tetrachloride selectivity, gaseous chlorine feed increases carbon tetrachloride selectivity, and chlorine feed in a gas-liquid mixture provides moderate carbon tetrachloride selectivity. This invention allows for flexible adjustment of the selectivity of dichloromethane, trichloromethane, and carbon tetrachloride products according to different feed states, flexibly adapting to market changes.

[0008] In this invention, selectivity refers to the proportion of one or two of dichloromethane, trichloromethane, and carbon tetrachloride, based on a total mass of 100%.

[0009] In some preferred embodiments, in the methane chloride production process described in the first aspect, the chlorine gas feed is in liquid form, and the target product is mainly composed of dichloromethane, or at least one of chloroform and carbon tetrachloride, with carbon tetrachloride accounting for less than 5% based on the total mass of dichloromethane, chloroform, and carbon tetrachloride (100%). Further, when the target product is mainly composed of dichloromethane, the carbon tetrachloride content is less than 5% based on the total mass of dichloromethane, chloroform, and carbon tetrachloride (100%).

[0010] In this invention, the main components of the target product refer to one or two of the following, based on the total mass of dichloromethane, trichloromethane, and carbon tetrachloride as 100%, with a total proportion of more than 50% among dichloromethane, trichloromethane, and carbon tetrachloride. It can be understood that the above description also covers the case where one or two of dichloromethane, trichloromethane, and carbon tetrachloride have a proportion of 0.

[0011] In some preferred embodiments, in the methane chloride production process described in the first aspect, the chlorine feed is in gaseous form, and the target product mainly consists of at least one of chloroform and carbon tetrachloride, with carbon tetrachloride accounting for more than 10% based on the total mass of dichloroform, chloroform, and carbon tetrachloride being 100%.

[0012] In some preferred embodiments, in the methane chloride production process described in the first aspect, the chlorine feed is in the form of a gas-liquid mixture, and the target product mainly consists of at least one of chloroform and carbon tetrachloride, with carbon tetrachloride accounting for 5% to 10% based on the total mass of dichloroform, chloroform, and carbon tetrachloride as 100%.

[0013] In some embodiments, the methane chloride production process described in the first aspect employs a chlorination reaction tower. Optionally, the chlorination reaction tower contains a heat exchange coil.

[0014] In some preferred embodiments, in the methane chloride production process described in the first aspect, the chlorination reaction temperature in the chlorination reaction tower is 70~120°C, more preferably 100~115°C, for example, a reaction temperature of 105°C.

[0015] In some preferred embodiments, in the methane chloride production process described in the first aspect, the chlorination reaction tower is connected to a chlorine inlet, a chloromethane inlet, a dichloromethane inlet, and an initiator / solvent inlet. The composition of the target product can be adjusted by changing the feeding method of the chlorine inlet, chloromethane inlet, dichloromethane inlet, and initiator / solvent inlet to either enter the chlorination reaction tower independently or be mixed before entering the chlorination reaction tower.

[0016] The initiator / solvent inlet refers to the inlet through which one or more of the initiator and solvent can be introduced.

[0017] Increasing the selectivity of carbon tetrachloride by having chlorine, chloromethane, dichloromethane, and initiator / solvent inlets fed into the chlorination tower independently can improve the selectivity of carbon tetrachloride. Increasing the selectivity of carbon tetrachloride by having chlorine, chloromethane, dichloromethane, and initiator / solvent inlets blended before feeding into the chlorination tower can reduce the selectivity of carbon tetrachloride.

[0018] In some preferred embodiments, in the methane chloride production process described in the first aspect, the chlorine inlet, chloromethane inlet, dichloromethane inlet and initiator / solvent inlet are fed into the chlorination reaction tower independently, and the target product mainly consists of at least one of chloroform and carbon tetrachloride, with carbon tetrachloride accounting for more than 10% based on the total mass of dichloromethane, chloroform and carbon tetrachloride as 100%.

[0019] In some preferred embodiments, in the methane chloride production process described in the first aspect, the chlorine, monochloromethane, dichloromethane, and initiator / solvent are fed into the chlorination reaction tower after being blended. The target product is mainly composed of dichloromethane, or at least one of trichloromethane and carbon tetrachloride, with carbon tetrachloride accounting for no more than 10% and further no more than 5% based on the total mass of dichloromethane, trichloromethane, and carbon tetrachloride (100%). Further, when the target product is mainly composed of dichloromethane, the carbon tetrachloride accounts for no more than 10% and further no more than 5% based on the total mass of dichloromethane, trichloromethane, and carbon tetrachloride (100%).

[0020] In some preferred embodiments, the methane chloride production process described in the first aspect employs a topologically optimized mixing feed distributor to achieve the blending. More preferably, the mixing feed distributor includes a conical main structure, comprising a bottom annular tube and multiple uniformly distributed connecting tubes coinciding with the generatrix of the conical main structure; one end of each connecting tube is connected to the main feed pipe, and the other end is connected to the annular tube; chlorine inlet, monochloromethane inlet, dichloromethane inlet, and initiator / solvent inlet are connected and converged to the main feed pipe; multiple outlet holes are uniformly distributed at the bottom of the annular tube. This invention, by mixing liquid chlorine with initiator / solvent, monochloromethane, and dichloromethane and designing an optimized distributor structure, controls the selectivity of carbon tetrachloride and reduces the proportion of carbon tetrachloride byproducts.

[0021] In some preferred embodiments, in the methane chloride production process described in the first aspect, the chlorination reaction tower includes a gas phase outlet, which is sequentially connected to a primary condenser and a secondary condenser. The composition of the target product can be adjusted by changing the connection method between the primary and secondary condensers, either by connecting the gas phase outlet of the primary condenser to the inlet of the secondary condenser or by connecting the liquid phase outlet of the primary condenser to the inlet of the secondary condenser.

[0022] Connecting the vapor phase outlet of the primary condenser to the inlet of the secondary condenser can reduce the selectivity of carbon tetrachloride; connecting the liquid phase outlet of the primary condenser to the inlet of the secondary condenser can improve the selectivity of carbon tetrachloride.

[0023] In some preferred embodiments, in the methane chloride production process described in the first aspect, the chlorination reaction tower includes a liquid phase reflux port, a gas phase outlet of the primary condenser connected to the inlet of the secondary condenser, and a liquid phase outlet of the secondary condenser connected to the liquid phase reflux port, which is at least used for heat transfer within the chlorination reaction tower. The target product is mainly composed of dichloromethane, or at least one of trichloromethane and carbon tetrachloride, with carbon tetrachloride accounting for less than 10% and further less than 5% based on the total mass of dichloromethane, trichloromethane, and carbon tetrachloride (100%). Further, when the target product is mainly composed of dichloromethane, the carbon tetrachloride accounting for less than 10% and further less than 5% based on the total mass of dichloromethane, trichloromethane, and carbon tetrachloride (100%).

[0024] In some preferred embodiments, in the methane chloride production process described in the first aspect, the chlorination reaction tower includes a liquid phase reflux port, the liquid phase outlet of the primary condenser is connected to the inlet of the secondary condenser, the liquid phase outlet of the secondary condenser is connected to the liquid phase reflux port, the secondary condenser is selectively turned on or off according to the heat exchange requirements of the chlorination reaction tower, so that the material at the liquid phase outlet of the secondary condenser is subcooled and saturated and refluxed to adjust the temperature inside the chlorination reaction tower, and the target product mainly consists of at least one of trichloromethane and carbon tetrachloride, and the proportion of carbon tetrachloride is not less than 10% based on the total mass of dichloromethane, trichloromethane and carbon tetrachloride as 100%.

[0025] In some preferred embodiments, in the methane chloride production process described in the first aspect, the liquid phase outlet or the gas phase outlet of the primary condenser is connected to a dehydrochlorination unit and can be switched between each other. That is, the liquid phase outlet and the gas phase outlet of the primary condenser can be arbitrarily switched to connect to the dehydrochlorination unit according to the composition of the target product. For example, when reducing the selectivity of carbon tetrachloride, the gas phase outlet of the primary condenser is connected to the inlet of the secondary condenser, and the liquid phase outlet of the primary condenser is connected to the dehydrochlorination unit; when increasing the selectivity of carbon tetrachloride, the liquid phase outlet of the primary condenser is connected to the inlet of the secondary condenser, and the gas phase outlet of the primary condenser is connected to the dehydrochlorination unit. Further, the dehydrochlorination unit can be the dehydrochlorination high-pressure tower described below.

[0026] In some preferred embodiments, in the methane chloride production process described in the first aspect, the vapor phase outlet of the secondary condenser is connected to a dehydrochlorination unit. Further, the dehydrochlorination unit may be the dehydrochlorination high-pressure tower described below.

[0027] In some preferred embodiments, in the methane chloride production process of the first aspect, the chlorination reaction tower includes a chlorination product outlet, which is sequentially connected to a high-pressure dehydrochlorination tower, a low-pressure dehydrochlorination tower, a monochloromethane tower, and an acid flash evaporator. The high-pressure dechlorination tower, the low-pressure dechlorination tower, and the acid flash evaporator are at least used to remove hydrogen chloride from the chlorination products and / or remove hydrogen chloride generated from the decomposition of the chlorination products. The monochloromethane tower is used at least to remove monochloromethane from the chlorination products; The chlorination reaction tower, the high-pressure dechlorination tower, the low-pressure dechlorination tower, the monochloromethane tower, and the acid flash evaporator are set with pressures following the pressure drop gradient.

[0028] This invention optimizes the entire system, making full use of energy and eliminating the need for alkaline washing and water washing; it designs a system-wide circulation scheme to achieve energy saving, consumption reduction, and flexible control of the selectivity of dichloromethane, trichloromethane, and carbon tetrachloride in the products.

[0029] The chlorinated product obtained after the chlorination reaction in the chlorination tower is discharged through the chlorinated product outlet and enters the dehydrochlorination high-pressure tower to remove hydrogen chloride. Pure hydrogen chloride is collected from the top of the dehydrochlorination high-pressure tower, while the bottom contains high-boiling-point substances entrained with hydrogen chloride. These high-boiling-point substances entrained with hydrogen chloride enter the dehydrochlorination low-pressure tower for further hydrogen chloride removal. The bottom of the dehydrochlorination low-pressure tower contains high-boiling-point substances without hydrogen chloride, while the top contains hydrogen chloride entrained with high-boiling-point substances. The high-boiling-point substances without hydrogen chloride enter the monochloromethane tower to remove monochloromethane. The material after monochloromethane removal enters the acid flash evaporator for further removal of hydrogen chloride and other substances produced by the decomposition of the chlorination products. The resulting material can be directly sent to the polychlorinated compound purification unit without alkaline washing / water washing.

[0030] In some preferred embodiments, in the methane chloride production process described in the first aspect, the liquid phase outlet or the gas phase outlet of the primary condenser is connected to the dehydrochlorination high-pressure tower and can be switched between each other.

[0031] In some preferred embodiments, in the methane chloride production process described in the first aspect, the gas phase outlet of the secondary condenser is connected to the dehydrochlorination high-pressure tower.

[0032] In some preferred embodiments, in the methane chloride production process described in the first aspect, the chlorination reaction pressure in the chlorination reaction tower is 10 to 50 bar, for example 26 bar, and more preferably 25 to 30 bar.

[0033] In some preferred embodiments, in the methane chloride production process described in the first aspect, the operating pressure of the dehydrochlorination high-pressure tower is 5 to 40 bar, for example 20 bar, 22 bar, etc., and more preferably 10 to 20 bar.

[0034] In some preferred embodiments, in the methane chloride production process described in the first aspect, the operating temperature of the dehydrochlorination high-pressure tower is above 0°C, for example, 32°C.

[0035] In some preferred embodiments, in the methane chloride production process described in the first aspect, the operating pressure of the dehydrochlorination low-pressure tower is 1 to 15 bar, for example 5 bar, 10 bar, etc., and more preferably 5 to 10 bar.

[0036] In some preferred embodiments, in the methane chloride production process described in the first aspect, the operating pressure of the monochloromethane tower is 0.5 to 10 bar, for example 4 bar, 5 bar, etc., and more preferably 0.5 to 5 bar.

[0037] In some preferred embodiments, in the methane chloride production process described in the first aspect, the operating pressure of the acid flash evaporator is 0.1 to 2 bar, for example 0.5 bar, 0.7 bar, etc., and more preferably 0.2 to 1 bar.

[0038] In some preferred embodiments, in the methane chloride production process described in the first aspect, the acid flash evaporator operates at a negative pressure.

[0039] In some preferred embodiments, the methane chloride production process described in the first aspect does not involve alkali washing and / or water washing processes.

[0040] In some preferred embodiments, in the methane chloride production process of the first aspect, the dehydrochlorination high-pressure tower includes a first hydrogen chloride outlet connected to a methanol chlorination unit, the methanol chlorination unit being used at least for the chlorination reaction of methanol and hydrogen chloride to produce chloromethane.

[0041] Preferably, the hydrogen chloride carrying high-boiling-point substances at the top of the low-pressure dechlorination tower is returned to the high-pressure dechlorination tower. In some preferred embodiments, in the methane chloride production process of the first aspect, the low-pressure dechlorination tower includes a second hydrogen chloride outlet connected to the high-pressure dechlorination tower, which is used to separate hydrogen chloride and high-boiling-point substances from the hydrogen chloride carrying high-boiling-point substances discharged from the second hydrogen chloride outlet.

[0042] In some preferred embodiments, in the methane chloride production process described in the first aspect, the monochloromethane tower includes a monochloromethane outlet, which is connected to the chlorination reaction tower to achieve the recycling of monochloromethane.

[0043] In some preferred embodiments, in the methane chloride production process of the first aspect, the acid flash evaporator includes a third hydrogen chloride outlet connected to a methanol chlorination unit, which is used at least for the chlorination reaction of methanol and hydrogen chloride to produce chloromethane.

[0044] In some preferred embodiments, in the methane chloride production process of the first aspect, the acid flash evaporator is connected to a polychlorinated compound refining unit, and the composition of the target product is adjusted by changing the composition of the material recycled back to the chlorination reaction tower from the high-pressure dehydrochlorination tower and / or the low-pressure dehydrochlorination tower and / or the monochloromethane tower, as well as the refining target of the polychlorinated compound refining unit.

[0045] In some preferred embodiments, in the methane chloride production process described in the first aspect, the material composition recycled back to the chlorination reaction tower from the high-pressure dehydrochlorination tower and / or the low-pressure dehydrochlorination tower and / or the monochloromethane tower includes dichloromethane, and the polychlorinated compound refining unit refines trichloromethane and / or carbon tetrachloride, with the target product mainly composed of at least one of trichloromethane and carbon tetrachloride.

[0046] Secondly, this invention provides a methane chloride production apparatus with adjustable product selectivity, including a chlorine inlet that allows for switching between gaseous, liquid, or gas-liquid mixed chlorine feed states. Specifically, the chlorine feed state can be arbitrarily selected from gaseous, liquid, and gas-liquid mixed states. The target product composition can be adjusted by changing the chlorine feed state. Liquid chlorine feed can reduce carbon tetrachloride selectivity, gaseous chlorine feed can increase carbon tetrachloride selectivity, and chlorine feed in a gas-liquid mixed state can achieve moderate carbon tetrachloride selectivity. This invention allows for flexible control of the selectivity of products dichloromethane, trichloromethane, and carbon tetrachloride by adjusting the chlorine feed state at the chlorine inlet, adapting flexibly to market changes.

[0047] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the chlorine feed is in liquid form, and the target product is mainly composed of dichloromethane, or at least one of trichloromethane and carbon tetrachloride, with carbon tetrachloride accounting for less than 5% based on the total mass of dichloromethane, trichloromethane, and carbon tetrachloride (100%). Further, when the target product is mainly composed of dichloromethane, the carbon tetrachloride content is less than 5% based on the total mass of dichloromethane, trichloromethane, and carbon tetrachloride (100%).

[0048] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the chlorine feed is in gaseous form, and the target product mainly consists of at least one of chloroform and carbon tetrachloride, with carbon tetrachloride accounting for more than 10% based on the total mass of dichloroform, chloroform, and carbon tetrachloride as 100%.

[0049] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the chlorine feed is in the form of a gas-liquid mixture, and the target product mainly consists of at least one of chloroform and carbon tetrachloride, with carbon tetrachloride accounting for 5% to 10% based on the total mass of dichloroform, chloroform, and carbon tetrachloride as 100%.

[0050] In some preferred embodiments, the methane chloride production apparatus described in the second aspect includes a chlorination reaction tower, with the chlorine inlet connected to the chlorination reaction tower. Optionally, a heat exchange coil is installed inside the chlorination reaction tower.

[0051] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the chlorination reaction temperature in the chlorination reaction tower is 70~120°C, more preferably 100~115°C, for example, a reaction temperature of 105°C.

[0052] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the chlorination reaction tower is further connected to a chloromethane inlet, a dichloromethane inlet, and an initiator / solvent inlet. The chlorine, chloromethane, dichloromethane, and initiator / solvent inlets can be fed into the chlorination reaction tower independently or mixed before entering, and these methods can be switched. That is, the feeding methods of the chlorine, chloromethane, dichloromethane, and initiator / solvent inlets can be arbitrarily selected from either independent feeding or mixed feeding. The composition of the target product can be adjusted by changing the feeding methods of the chlorine, chloromethane, dichloromethane, and initiator / solvent inlets to either independent feeding or mixed feeding. Increasing the selectivity of carbon tetrachloride by having chlorine, chloromethane, dichloromethane, and initiator / solvent inlets fed into the chlorination tower independently can improve the selectivity of carbon tetrachloride. Increasing the selectivity of carbon tetrachloride by having chlorine, chloromethane, dichloromethane, and initiator / solvent inlets blended before feeding into the chlorination tower can reduce the selectivity of carbon tetrachloride.

[0053] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the chlorine inlet, chloromethane inlet, dichloromethane inlet and initiator / solvent inlet are fed into the chlorination reaction tower independently, and the target product mainly consists of at least one of chloroform and carbon tetrachloride, with carbon tetrachloride accounting for more than 10% based on the total mass of dichloromethane, chloroform and carbon tetrachloride as 100%.

[0054] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the chlorine inlet, chloromethane inlet, dichloromethane inlet, and initiator / solvent inlet are fed into the chlorination reaction tower after being blended. The target product is mainly composed of dichloromethane, or at least one of chloroform and carbon tetrachloride, with carbon tetrachloride accounting for no more than 10% and further no more than 5% based on the total mass of dichloromethane, chloroform, and carbon tetrachloride (100%). Further, when the target product is mainly composed of dichloromethane, the carbon tetrachloride accounts for no more than 10% and further no more than 5% based on the total mass of dichloromethane, chloroform, and carbon tetrachloride (100%).

[0055] In some preferred embodiments, the methane chloride production apparatus described in the second aspect includes a topologically optimized mixing feed distributor for achieving the blending. More preferably, the mixing feed distributor includes a conical main structure, comprising an annular tube at the bottom and multiple uniformly distributed connecting pipes coinciding with the generatrix of the conical main structure; one end of each connecting pipe is connected to the main feed pipe, and the other end is connected to the annular tube; chlorine inlet, chloromethane inlet, dichloromethane inlet, and initiator / solvent inlet are connected and converged to the main feed pipe; multiple outlet holes are uniformly distributed at the bottom of the annular tube. This invention, by mixing liquid chlorine with initiator / solvent, chloromethane, and dichloromethane and designing an optimized distributor structure, controls the selectivity of carbon tetrachloride and reduces the proportion of carbon tetrachloride byproducts.

[0056] In some preferred embodiments, the methane chloride production apparatus described in the second aspect includes a chlorination reaction tower comprising a gas phase outlet connected in sequence to a primary condenser and a secondary condenser. The primary and secondary condensers are connected in a manner that allows for switching between the primary condenser gas phase outlet and the secondary condenser inlet, or vice versa. That is, the connection method can be arbitrarily selected between either the primary condenser gas phase outlet and the secondary condenser inlet or the primary condenser liquid phase outlet and the secondary condenser inlet. The target product composition can be adjusted by changing the connection method between the primary and secondary condensers. Connecting the primary condenser gas phase outlet to the secondary condenser inlet or vice versa. Connecting the primary condenser gas phase outlet to the secondary condenser inlet reduces the selectivity for carbon tetrachloride; connecting the primary condenser liquid phase outlet to the secondary condenser inlet increases the selectivity for carbon tetrachloride.

[0057] In some preferred embodiments, in the methane chloride production apparatus of the second aspect, the chlorination reaction tower includes a liquid phase reflux port, and the liquid phase outlet of the secondary condenser is connected to the liquid phase reflux port for at least heat transfer within the chlorination reaction tower.

[0058] When the gas phase outlet of the primary condenser is connected to the inlet of the secondary condenser and the liquid phase outlet of the secondary condenser is connected to the liquid phase reflux port, the target product mainly consists of dichloromethane, or at least one of trichloromethane and carbon tetrachloride, with carbon tetrachloride accounting for less than 10% and further less than 5% based on the total mass of dichloromethane, trichloromethane, and carbon tetrachloride (100%). Furthermore, when the target product mainly consists of dichloromethane, the carbon tetrachloride accounting for less than 10% and further less than 5% based on the total mass of dichloromethane, trichloromethane, and carbon tetrachloride (100%).

[0059] When the liquid phase outlet of the primary condenser is connected to the inlet of the secondary condenser and the liquid phase outlet of the secondary condenser is connected to the liquid phase reflux port, the secondary condenser can be turned on or off according to the heat exchange requirements of the chlorination reaction tower, so that the material at the liquid phase outlet of the secondary condenser is subcooled and refluxed or saturated to regulate the temperature inside the chlorination reaction tower. The target product mainly consists of at least one of trichloromethane and carbon tetrachloride, and the proportion of carbon tetrachloride is not less than 10% based on the total mass of dichloromethane, trichloromethane and carbon tetrachloride as 100%.

[0060] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the liquid phase outlet or the gas phase outlet of the primary condenser is connected to a dehydrochlorination unit and can be switched between each other. That is, the liquid phase outlet and the gas phase outlet of the primary condenser can be arbitrarily switched to connect to the dehydrochlorination unit according to the composition of the target product. For example: when reducing the selectivity of carbon tetrachloride, the gas phase outlet of the primary condenser is connected to the inlet of the secondary condenser, and the liquid phase outlet of the primary condenser is connected to the dehydrochlorination unit; when increasing the selectivity of carbon tetrachloride, the liquid phase outlet of the primary condenser is connected to the inlet of the secondary condenser, and the gas phase outlet of the primary condenser is connected to the dehydrochlorination unit. Further, the dehydrochlorination unit can be the dehydrochlorination high-pressure tower.

[0061] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the gas phase outlet of the secondary condenser is connected to a dehydrochlorination unit. Further, the dehydrochlorination unit may be the aforementioned high-pressure dehydrochlorination tower.

[0062] In some preferred embodiments, the methane chloride production apparatus of the second aspect includes a chlorination reaction tower comprising a chlorination product outlet, the chlorination product outlet being sequentially connected to a high-pressure dehydrochlorination tower, a low-pressure dehydrochlorination tower, a monochloromethane tower, and an acid flash evaporator. The high-pressure dechlorination tower, the low-pressure dechlorination tower, and the acid flash evaporator are at least used to remove hydrogen chloride from the chlorination products and / or remove hydrogen chloride generated from the decomposition of the chlorination products. The monochloromethane tower is used at least to remove monochloromethane from the chlorination products; The chlorination reaction tower, the high-pressure dechlorination tower, the low-pressure dechlorination tower, the monochloromethane tower, and the acid flash evaporator are set with pressures following the pressure drop gradient.

[0063] This invention optimizes the entire system, making full use of energy and eliminating the need for alkaline washing and water washing; it designs a system-wide circulation scheme to achieve energy saving, consumption reduction, and flexible control of the selectivity of dichloromethane, trichloromethane, and carbon tetrachloride in the products.

[0064] The chlorinated product obtained after the chlorination reaction in the chlorination tower is discharged through the chlorinated product outlet and enters the dehydrochlorination high-pressure tower to remove hydrogen chloride. Pure hydrogen chloride is collected from the top of the dehydrochlorination high-pressure tower, while the bottom contains high-boiling-point substances entrained with hydrogen chloride. These high-boiling-point substances entrained with hydrogen chloride enter the dehydrochlorination low-pressure tower for further hydrogen chloride removal. The bottom of the dehydrochlorination low-pressure tower contains high-boiling-point substances without hydrogen chloride, while the top contains hydrogen chloride entrained with high-boiling-point substances. The high-boiling-point substances without hydrogen chloride enter the monochloromethane tower to remove monochloromethane. The material after monochloromethane removal enters the acid flash evaporator for further removal of hydrogen chloride and other substances produced by the decomposition of the chlorination products. The resulting material can be directly sent to the polychlorinated compound purification unit without alkaline washing / water washing.

[0065] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the liquid phase outlet or the gas phase outlet of the primary condenser is connected to the dehydrochlorination high-pressure tower and can be switched between each other.

[0066] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the gas phase outlet of the secondary condenser is connected to the high-pressure dechlorination tower.

[0067] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the chlorination reaction pressure in the chlorination reaction tower is 10 to 50 bar, more preferably 25 to 30 bar.

[0068] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the operating pressure of the dehydrochlorination high-pressure tower is 5 to 40 bar, more preferably 10 to 20 bar.

[0069] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the operating temperature of the dehydrochlorination high-pressure tower is above 0°C.

[0070] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the operating pressure of the dehydrochlorination low-pressure tower is 1 to 15 bar, more preferably 5 to 10 bar.

[0071] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the operating pressure of the monochloromethane tower is 0.5 to 10 bar, more preferably 0.5 to 5 bar.

[0072] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the operating pressure of the acid flash evaporator is 0.1 to 2 bar, more preferably 0.2 to 1 bar.

[0073] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the acid flash evaporator operates at a negative pressure.

[0074] In some preferred embodiments, the methane chloride production apparatus described in the second aspect is free of alkali washing and / or water washing devices.

[0075] In some preferred embodiments, in the methane chloride production apparatus of the second aspect, the dehydrochlorination high-pressure tower includes a first hydrogen chloride outlet connected to a methanol chlorination unit, the methanol chlorination unit being used at least for the chlorination reaction of methanol and hydrogen chloride to produce chloromethane.

[0076] Preferably, the hydrogen chloride carrying high-boiling-point substances at the top of the low-pressure dechlorination tower is returned to the high-pressure dechlorination tower. In some preferred embodiments, in the methane chloride production apparatus of the second aspect, the low-pressure dechlorination tower includes a second hydrogen chloride outlet connected to the high-pressure dechlorination tower, which is used to separate hydrogen chloride and high-boiling-point substances from the hydrogen chloride carrying high-boiling-point substances discharged from the second hydrogen chloride outlet.

[0077] In some preferred embodiments, in the methane chloride production apparatus of the second aspect, the monochloromethane tower includes a monochloromethane outlet connected to the chlorination reaction tower to achieve monochloromethane recycling.

[0078] In some preferred embodiments, in the methane chloride production apparatus of the second aspect, the acid flash evaporator includes a third hydrogen chloride outlet connected to a methanol chlorination unit, which is used at least for the chlorination reaction of methanol and hydrogen chloride to produce chloromethane.

[0079] In some preferred embodiments, in the methane chloride production apparatus described in the second aspect, the acid flash evaporator is connected to a polychlorinated compound refining unit, and the composition of the material recycled back to the chlorination reaction tower from the high-pressure dehydrochlorination tower and / or the low-pressure dehydrochlorination tower and / or the monochloromethane tower, as well as the refining target of the polychlorinated compound refining unit, are adjustable. The target product composition can be adjusted by changing the composition of the material recycled back to the chlorination reaction tower from the high-pressure dehydrochlorination tower and / or the low-pressure dehydrochlorination tower and / or the monochloromethane tower, as well as the refining target of the polychlorinated compound refining unit.

[0080] Thirdly, the present invention provides the application of the methane chloride production apparatus described in the second aspect in the production of methane chloride.

[0081] Fourthly, the present invention provides a methane chloride production process with adjustable product selectivity, which uses the methane chloride production apparatus described in the second aspect to produce methane chloride.

[0082] The methane chloride production process described in the fourth aspect can be further selected and optimized by referring to the methane chloride production process described in the first aspect.

[0083] Fifthly, the present invention provides a methane chloride production process with adjustable product selectivity, employing a chlorination reaction tower connected to a chlorine inlet, a monochloromethane inlet, a dichloromethane inlet, and an initiator / solvent inlet. The target product composition can be adjusted by changing the feeding method of the chlorine inlet, monochloromethane inlet, dichloromethane inlet, and initiator / solvent inlet to either enter the chlorination reaction tower independently or be mixed before entering the chlorination reaction tower.

[0084] Increasing the selectivity of carbon tetrachloride by having chlorine, chloromethane, dichloromethane, and initiator / solvent inlets fed into the chlorination tower independently can improve the selectivity of carbon tetrachloride. Increasing the selectivity of carbon tetrachloride by having chlorine, chloromethane, dichloromethane, and initiator / solvent inlets blended before feeding into the chlorination tower can reduce the selectivity of carbon tetrachloride.

[0085] The methane chloride production process described in the fifth aspect can be further selected and optimized by referring to the methane chloride production process described in the first aspect.

[0086] Sixthly, the present invention provides a methane chloride production apparatus with adjustable product selectivity, comprising a chlorination reaction tower connected to a chlorine inlet, a monochloromethane inlet, a dichloromethane inlet, and an initiator / solvent inlet. The chlorine, monochloromethane, dichloromethane, and initiator / solvent inlets can be fed into the chlorination reaction tower independently or mixed before entering, and these feeding methods can be switched. Specifically, the feeding methods of the chlorine, monochloromethane, dichloromethane, and initiator / solvent inlets can be arbitrarily switched between independent feeding and mixed feeding. The target product composition can be adjusted by changing the feeding methods of the chlorine, monochloromethane, dichloromethane, and initiator / solvent inlets to either independent feeding or mixed feeding. Increasing the selectivity of carbon tetrachloride by having chlorine, chloromethane, dichloromethane, and initiator / solvent inlets fed into the chlorination tower independently can improve the selectivity of carbon tetrachloride. Increasing the selectivity of carbon tetrachloride by having chlorine, chloromethane, dichloromethane, and initiator / solvent inlets blended before feeding into the chlorination tower can reduce the selectivity of carbon tetrachloride.

[0087] The methane chloride production apparatus described in the sixth aspect can be further selected and optimized with reference to the methane chloride production apparatus described in the second aspect.

[0088] In a seventh aspect, the present invention provides the application of the methane chloride production apparatus described in the sixth aspect in the production of methane chloride.

[0089] Eighthly, the present invention provides a methane chloride production process with adjustable product selectivity, which uses the methane chloride production apparatus described in the sixth aspect to produce methane chloride.

[0090] Ninthly, the present invention provides a methane chloride production process with adjustable product selectivity, employing a chlorination reaction tower, the chlorination reaction tower including a gas phase outlet, the gas phase outlet being sequentially connected to a primary condenser and a secondary condenser, the target product composition being adjusted by changing the connection method of the primary condenser and the secondary condenser to either connecting the gas phase outlet of the primary condenser to the inlet of the secondary condenser or connecting the liquid phase outlet of the primary condenser to the inlet of the secondary condenser.

[0091] Connecting the vapor phase outlet of the primary condenser to the inlet of the secondary condenser can reduce the selectivity of carbon tetrachloride; connecting the liquid phase outlet of the primary condenser to the inlet of the secondary condenser can improve the selectivity of carbon tetrachloride.

[0092] In some preferred embodiments, in the methane chloride production process described in aspect nine, the liquid phase outlet or the gas phase outlet of the primary condenser is connected to a dehydrochlorination unit and can be switched between each other. That is, the liquid phase outlet and the gas phase outlet of the primary condenser can be arbitrarily switched to connect to the dehydrochlorination unit according to the composition of the target product. For example: when reducing the selectivity of carbon tetrachloride, the gas phase outlet of the primary condenser is connected to the inlet of the secondary condenser, and the liquid phase outlet of the primary condenser is connected to the dehydrochlorination unit; when increasing the selectivity of carbon tetrachloride, the liquid phase outlet of the primary condenser is connected to the inlet of the secondary condenser, and the gas phase outlet of the primary condenser is connected to the dehydrochlorination unit. Further, the dehydrochlorination unit can be the aforementioned high-pressure dehydrochlorination tower.

[0093] The methane chloride production process described in the ninth aspect can be further selected and optimized with reference to the methane chloride production process described in the first aspect.

[0094] In a tenth aspect, the present invention provides a methane chloride production apparatus with adjustable product selectivity, comprising a chlorination reaction tower, wherein the chlorination reaction tower includes a gas phase outlet, the gas phase outlet being sequentially connected to a primary condenser and a secondary condenser, the connection method of the primary and secondary condensers being either the gas phase outlet of the primary condenser connected to the inlet of the secondary condenser or the liquid phase outlet of the primary condenser connected to the inlet of the secondary condenser, and being switchable between the two; that is, the connection method of the primary and secondary condensers can be arbitrarily switched between the two: the gas phase outlet of the primary condenser connected to the inlet of the secondary condenser and the liquid phase outlet of the primary condenser connected to the inlet of the secondary condenser. The target product composition can be adjusted by changing the connection method of the primary and secondary condensers to either the gas phase outlet of the primary condenser connected to the inlet of the secondary condenser or the liquid phase outlet of the primary condenser connected to the inlet of the secondary condenser. Connecting the gas phase outlet of the primary condenser to the inlet of the secondary condenser can reduce the selectivity of carbon tetrachloride; connecting the liquid phase outlet of the primary condenser to the inlet of the secondary condenser can increase the selectivity of carbon tetrachloride.

[0095] In some preferred embodiments, in the methane chloride production apparatus described in aspect ten, the liquid phase outlet or the gas phase outlet of the primary condenser is connected to a dehydrochlorination unit and can be switched between each other. That is, the liquid phase outlet and the gas phase outlet of the primary condenser can be arbitrarily switched to connect to the dehydrochlorination unit according to the composition of the target product. For example: when reducing the selectivity of carbon tetrachloride, the gas phase outlet of the primary condenser is connected to the inlet of the secondary condenser, and the liquid phase outlet of the primary condenser is connected to the dehydrochlorination unit; when increasing the selectivity of carbon tetrachloride, the liquid phase outlet of the primary condenser is connected to the inlet of the secondary condenser, and the gas phase outlet of the primary condenser is connected to the dehydrochlorination unit. Further, the dehydrochlorination unit can be the dehydrochlorination high-pressure tower.

[0096] The methane chloride production apparatus described in the tenth aspect can be further selected and optimized with reference to the methane chloride production apparatus described in the second aspect.

[0097] Eleventhly, the present invention provides the application of the methane chloride production apparatus described in the tenth aspect in the production of methane chloride.

[0098] In a twelfth aspect, the present invention provides a methane chloride production process with adjustable product selectivity, using the methane chloride production apparatus described in the tenth aspect to produce methane chloride.

[0099] In a thirteenth aspect, the present invention provides a methane chloride production process with adjustable product selectivity, employing a chlorination reaction tower, the chlorination reaction tower including a chlorinated product outlet, the chlorinated product outlet being sequentially connected to a high-pressure dehydrochlorination tower, a low-pressure dehydrochlorination tower, a monochloromethane tower and an acid flash evaporator. The high-pressure dechlorination tower, the low-pressure dechlorination tower, and the acid flash evaporator are at least used to remove hydrogen chloride from the chlorination products and / or remove hydrogen chloride generated from the decomposition of the chlorination products. The monochloromethane tower is used at least to remove monochloromethane from the chlorination products; The chlorination reaction tower, the high-pressure dechlorination tower, the low-pressure dechlorination tower, the monochloromethane tower, and the acid flash evaporator are set with pressures following the pressure drop gradient.

[0100] This invention optimizes the entire system, making full use of energy and eliminating the need for alkaline washing and water washing; it designs a system-wide circulation scheme to achieve energy saving, consumption reduction, and flexible control of the selectivity of dichloromethane, trichloromethane, and carbon tetrachloride in the products.

[0101] The chlorinated product obtained after the chlorination reaction in the chlorination tower is discharged through the chlorinated product outlet and enters the dehydrochlorination high-pressure tower to remove hydrogen chloride. Pure hydrogen chloride is collected from the top of the dehydrochlorination high-pressure tower, while the bottom contains high-boiling-point substances entrained with hydrogen chloride. These high-boiling-point substances entrained with hydrogen chloride enter the dehydrochlorination low-pressure tower for further hydrogen chloride removal. The bottom of the dehydrochlorination low-pressure tower contains high-boiling-point substances without hydrogen chloride, while the top contains hydrogen chloride entrained with high-boiling-point substances. The high-boiling-point substances without hydrogen chloride enter the monochloromethane tower to remove monochloromethane. The material after monochloromethane removal enters the acid flash evaporator for further removal of hydrogen chloride and other substances produced by the decomposition of the chlorination products. The resulting material can be directly sent to the polychlorinated compound purification unit without alkaline washing / water washing.

[0102] The methane chloride production process described in the thirteenth aspect can be further selected and optimized by referring to the methane chloride production process described in the first aspect.

[0103] In a fourteenth aspect, the present invention provides a methane chloride production apparatus with adjustable product selectivity, comprising a chlorination reaction tower, the chlorination reaction tower including a chlorinated product outlet, the chlorinated product outlet being sequentially connected to a high-pressure dehydrochlorination tower, a low-pressure dehydrochlorination tower, a monochloromethane tower and an acid flash evaporator. The high-pressure dechlorination tower, the low-pressure dechlorination tower, and the acid flash evaporator are at least used to remove hydrogen chloride from the chlorination products and / or remove hydrogen chloride generated from the decomposition of the chlorination products. The monochloromethane tower is used at least to remove monochloromethane from the chlorination products; The chlorination reaction tower, the high-pressure dechlorination tower, the low-pressure dechlorination tower, the monochloromethane tower, and the acid flash evaporator are set with pressures following the pressure drop gradient.

[0104] This invention optimizes the entire system, making full use of energy and eliminating the need for alkaline washing and water washing; it designs a system-wide circulation scheme to achieve energy saving, consumption reduction, and flexible control of the selectivity of dichloromethane, trichloromethane, and carbon tetrachloride in the products.

[0105] The chlorinated product obtained after the chlorination reaction in the chlorination tower is discharged through the chlorinated product outlet and enters the dehydrochlorination high-pressure tower to remove hydrogen chloride. Pure hydrogen chloride is collected from the top of the dehydrochlorination high-pressure tower, while the bottom contains high-boiling-point substances entrained with hydrogen chloride. These high-boiling-point substances entrained with hydrogen chloride enter the dehydrochlorination low-pressure tower for further hydrogen chloride removal. The bottom of the dehydrochlorination low-pressure tower contains high-boiling-point substances without hydrogen chloride, while the top contains hydrogen chloride entrained with high-boiling-point substances. The high-boiling-point substances without hydrogen chloride enter the monochloromethane tower to remove monochloromethane. The material after monochloromethane removal enters the acid flash evaporator for further removal of hydrogen chloride and other substances produced by the decomposition of the chlorination products. The resulting material can be directly sent to the polychlorinated compound purification unit without alkaline washing / water washing.

[0106] The methane chloride production apparatus described in the fourteenth aspect can be further selected and optimized with reference to the methane chloride production apparatus described in the second aspect.

[0107] In a fifteenth aspect, the present invention provides the application of the methane chloride production apparatus described in the fourteenth aspect in the production of methane chloride.

[0108] In a sixteenth aspect, the present invention provides a methane chloride production process with adjustable product selectivity, using the methane chloride production apparatus described in the fourteenth aspect to produce methane chloride.

[0109] Each example, technical solution, technical means, and technical feature listed in this invention can be arbitrarily selected to form a single technical solution or arbitrarily combined to form a combined technical solution.

[0110] Compared with the prior art, the beneficial effects of this invention are as follows: 1) This invention can solve the problems of high energy consumption, complex system and uncontrollable product ratio in existing processes. Under the appropriate product selectivity requirements, liquid chlorine is selected as feed, and the heat of reaction is removed by vaporization, which saves the energy consumption of the original liquid chlorine vaporization and vaporization equipment.

[0111] 2) Based on reaction kinetics research, reactor flow field research, and full-process simulation optimization, the proposed methane chloride production process and equipment have adjustable product selectivity and are highly efficient and energy-saving.

[0112] 3) The chlorine feed form of this invention can be gas, liquid, or a gas-liquid mixture, and the chlorine feed form can be switched and adjusted according to the composition of the target product. By controlling the chlorine feed state, product selectivity can be adjusted to adapt to flexible and ever-changing market demands. If the target product is mainly composed of dichloromethane, and low production of trichloromethane and carbon tetrachloride is required, liquid feed is preferred; if the target product is mainly composed of trichloromethane and / or carbon tetrachloride, and the mass ratio of carbon tetrachloride in the three products (dichloromethane, trichloromethane, and carbon tetrachloride) is required to be greater than 10%, gas feed is preferred; if the target product is mainly composed of trichloromethane and / or carbon tetrachloride, and the mass ratio of carbon tetrachloride in the three products (dichloromethane, trichloromethane, and carbon tetrachloride) is required to be controlled between 5% and 10%, a gas-liquid mixture feed is preferred; if the target product is mainly composed of trichloromethane and / or carbon tetrachloride, and the mass ratio of carbon tetrachloride in the three products (dichloromethane, trichloromethane, and carbon tetrachloride) is required to be less than 5%, liquid feed is preferred.

[0113] 4) When the main components of the target product are chloroform and / or carbon tetrachloride, and the mass ratio of carbon tetrachloride in the three products (dichloroform, chloroform, and carbon tetrachloride) is required to be greater than 10%, the chlorine, chloroform, dichloroform, and initiator / solvent inlets shall be fed into the reaction system independently. When the main component of the target product is dichloroform, or when the main components of the target product are chloroform and / or carbon tetrachloride, and the mass ratio of carbon tetrachloride in the three products (dichloroform, chloroform, and carbon tetrachloride) is required to be less than 10%, mixed feeding is preferred.

[0114] 5) Points 3) and 4) above utilize the dual-variable adjustment of the chlorine feed phase and feeding method to regulate the mixing efficiency within the reaction system. Without major modifications to the equipment or system, the reaction can be directed towards either the main reaction or the side reactions, achieving flexible control over the target product ratio. Simultaneously, the chlorine feed state can be precisely specified according to product selectivity requirements, maximizing the utilization of its latent heat of vaporization and reducing the heat transfer load on the reactor, resulting in significant energy savings.

[0115] 6) The structure of the mixing feed distributor adopts a topology optimization form to premix four feed streams, which are then evenly dispersed by a conical distributor, effectively improving the mixing efficiency and avoiding the problem of uneven flow rate and pressure drop in traditional ring-type flow distributors.

[0116] 7) The shell-side gas and liquid phase inlets and outlets of both the primary and secondary condensers can be freely connected, allowing for flexible control of temperature and concentration distribution within the reaction system. Specifically: If the selectivity of carbon tetrachloride in the target product is required to be less than 10%, the liquid phase outlet of the primary condenser is sent to the post-separation system, and the gas phase outlet is connected to the inlet of the secondary condenser. The liquid phase outlet of the secondary condenser is then refluxed back into the chlorination reaction tower for heat removal, while the gas phase outlet is sent to the post-separation system. This reduces the reflux of chloroform into the reactor and suppresses the side reaction that generates carbon tetrachloride. If the target product is primarily composed of chloroform and / or carbon tetrachloride, and the total mass of dichloromethane, chloroform, and carbon tetrachloride is 100%, with carbon tetrachloride accounting for no less than 10%, the gas phase outlet of the primary condenser is sent to the post-separation system, and the liquid phase outlet is connected to the inlet of the secondary condenser. The liquid phase outlet of the secondary condenser is then refluxed back into the chlorination reaction tower for heat removal. The secondary condenser can be selectively opened or closed according to the heat exchange requirements of the reaction system, allowing for subcooled or saturated reflux of the material to regulate the temperature within the reaction system.

[0117] 8) The present invention sets the pressure of each unit according to the pressure drop gradient, so as to minimize the power transmission equipment of the whole system and make full use of the high pressure energy of the reactor.

[0118] 9) The liquid outlet from the acid flash evaporator of this invention can be directly sent to the polychlorinated compound refining unit without alkaline washing / water washing. The optimized design of the entire process eliminates the need for alkaline washing / water washing units, saving equipment investment and operating costs, and reducing wastewater discharge.

[0119] 10) This invention reduces the operating pressure of the chloromethane tower and adds an acid flash evaporator, eliminating the need for alkali / water washing to remove hydrogen chloride. Current alkali washing primarily removes hydrogen chloride produced by the decomposition of chlorides in the chloromethane tower bottom. This invention lowers the chloromethane tower pressure and bottom temperature, while simultaneously increasing the distillate recovery rate, allowing some dichloromethane to be carried back to the reaction system with the chloromethane, ensuring sufficient removal of hydrogen chloride. Furthermore, a negative-pressure acid flash evaporator is installed to ensure that the material is free of hydrogen chloride before entering the refining unit. Therefore, alkali and water washing are unnecessary, making the system simpler, more efficient, and reducing wastewater discharge.

[0120] 11) This invention employs a coupling of low-pressure and high-pressure hydrogen chloride towers to maintain high pressure in the rectification section, thereby increasing the hydrogen chloride separation temperature to above zero and reducing the energy consumption of the condenser; while maintaining low pressure in the stripping section to reduce the reboiling temperature of chloromethane and reduce the energy consumption of the reboiler.

[0121] 12) When the target product mainly consists of chloroform and / or carbon tetrachloride, with dichloromethane as an intermediate, the dichloromethane separation unit in the purification unit can be eliminated. Instead, crude dichloromethane can be directly extracted from the lower part of the dehydrochlorination tower and the middle part of the monochloromethane tower and recycled back to the reaction system. This design saves on the number of system units and energy consumption in dichloromethane purification; furthermore, the temperature of the reaction system and the selectivity of the outlet product can be controlled by adjusting the temperature and flow rate of the reflux stream. Attached Figure Description

[0122] Figure 1 This is a schematic diagram of the chlorine inlet structure of the methane chloride production unit with adjustable product selectivity in Example 1.

[0123] Figure 2 This is a schematic diagram of the chlorination reaction tower, chlorine inlet, monochloromethane inlet, dichloromethane inlet, and initiator / solvent inlet of the methane chloride production apparatus with adjustable product selectivity in Example 2.

[0124] Figure 3 This is a schematic diagram of the topology-optimized mixing feed distributor structure in the methane chloride production unit with adjustable product selectivity in Example 3.

[0125] Figure 4 This is a schematic diagram of the connection method between the gas phase outlet of the primary condenser and the inlet of the secondary condenser in the methane chloride production unit with adjustable product selectivity, as shown in Example 4.

[0126] Figure 5 This is a schematic diagram of the connection relationship of the methane chloride production unit with adjustable product selectivity in Example 5. Detailed Implementation

[0127] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0128] Unless otherwise specified, the operating methods in the following examples are generally performed under conventional conditions or as recommended by the manufacturer.

[0129] Example 1: See Figure 1A methane chloride production apparatus with adjustable product selectivity includes a chlorine inlet 1, which is connected to a gaseous chlorine pipeline 101 and a liquid chlorine pipeline 102. A gaseous chlorine regulating valve 103 is installed on the gaseous chlorine pipeline 101, and a liquid chlorine regulating valve 104 is installed on the gaseous chlorine pipeline 102. This design allows the chlorine feed form of the chlorine inlet 1 to be arbitrarily switched between gaseous, liquid, and gas-liquid mixtures. For example, when the chlorine feed form is gaseous, the liquid chlorine regulating valve 104 is closed. 04. Open the gaseous chlorine regulating valve 103, and the gaseous chlorine pipeline 101 supplies gaseous chlorine to the chlorine inlet 1; when the chlorine feed form is liquid, close the gaseous chlorine regulating valve 103, open the liquid chlorine regulating valve 104, and the liquid chlorine pipeline 102 supplies liquid chlorine to the chlorine inlet 1; when the chlorine feed form is a gas-liquid mixture, open the liquid chlorine regulating valve 104 and the gaseous chlorine regulating valve 103 at the same time, and the gaseous chlorine pipeline 101 and the liquid chlorine pipeline 102 simultaneously supply gaseous chlorine and liquid chlorine to the chlorine inlet 1 to form a gas-liquid mixture.

[0130] The opening degrees of the gaseous chlorine regulating valve 103 and the liquid chlorine regulating valve 104 are adjustable, thereby adjusting the ratio of gaseous chlorine and liquid chlorine in the gas-liquid mixture.

[0131] The methane chloride production apparatus of this embodiment can adjust the composition of the target product by changing the chlorine feed form to gas, liquid, or gas-liquid mixture.

[0132] A methane chloride production process with adjustable product selectivity adjusts the composition of the target product by changing the form of chlorine feed to gas, liquid, or gas-liquid mixture. Specifically, the methane chloride production apparatus of this embodiment can be used.

[0133] Using the methane chloride production apparatus and process of this embodiment, liquid chlorine feed can reduce carbon tetrachloride selectivity, gaseous chlorine feed can increase carbon tetrachloride selectivity, and chlorine feed in a gas-liquid mixed state can achieve moderate carbon tetrachloride selectivity. By adjusting the chlorine feed form at the chlorine inlet, the selectivity of dichloromethane, trichloromethane, and carbon tetrachloride can be flexibly controlled according to different feed states, adapting flexibly to market changes.

[0134] Example 2: like Figure 2As shown, a methane chloride production apparatus with adjustable product selectivity includes a chlorination reaction tower 5. The chlorination reaction tower 5 is connected to a chlorine inlet 1, a monochloromethane inlet 2, a dichloromethane inlet 3, and an initiator / solvent inlet 4. Switching valves 105 are installed on the connecting pipelines of chlorine inlet 1, monochloromethane inlet 2, dichloromethane inlet 3, and initiator / solvent inlet 4 to the chlorination reaction tower 5. By controlling the switching valves 105, the feeding method of each inlet can be controlled to either enter the chlorination reaction tower 5 independently or be mixed before entering the chlorination reaction tower 5. This design allows for arbitrary switching between the two feeding methods: independent entry into the chlorine inlet 1, monochloromethane inlet 2, dichloromethane inlet 3, and initiator / solvent inlet 4, and the method of mixed entry into the chlorination reaction tower 5. The target product composition can be adjusted by changing the feeding method of chlorine inlet 1, monochloromethane inlet 2, dichloromethane inlet 3, and initiator / solvent inlet 4 to either enter the chlorination reaction tower 5 independently or be mixed before entering the chlorination reaction tower 5.

[0135] A methane chloride production process with adjustable product selectivity employs a chlorination reaction tower connected to a chlorine inlet, a monochloromethane inlet, a dichloromethane inlet, and an initiator / solvent inlet. The target product composition can be adjusted by changing the feeding methods of these inlets—either allowing them to enter the chlorination reaction tower independently or to blend them before entering. Specifically, the methane chloride production apparatus of this embodiment can be used.

[0136] Using the methane chloride production apparatus and process of this embodiment, chlorine inlet 1, monochloromethane inlet 2, dichloromethane inlet 3 and initiator / solvent inlet 4 are fed into the chlorination reaction tower 5 in their own independent manner, which can improve the selectivity of carbon tetrachloride; chlorine inlet 1, monochloromethane inlet 2, dichloromethane inlet 3 and initiator / solvent inlet 4 are fed into the chlorination reaction tower 5 in a mixed manner, which can reduce the selectivity of carbon tetrachloride.

[0137] Example 3: like Figure 3 As shown, a methane chloride production apparatus with adjustable product selectivity is provided. Based on the methane chloride production apparatus of Example 2, a topology-optimized mixing feed distributor is added to achieve the aforementioned blending. The mixing feed distributor includes a conical main structure 106, which can be installed inside the chlorination reaction tower 5. The conical main structure 106 includes a bottom annular pipe 107 and multiple evenly distributed connecting pipes 108 coinciding with the generatrix of the conical main structure 106. One end of each connecting pipe 108 is connected to a main feed pipe 109, and the other end is connected to the annular pipe 107. Chlorine inlet 1, monochloromethane inlet 2, dichloromethane inlet 3, and initiator / solvent inlet 4 converge to the main feed pipe 109. Multiple outlet holes (not shown) are evenly distributed at the bottom of the annular pipe 107.

[0138] A methane chloride production process with adjustable product selectivity can be implemented using the methane chloride production apparatus of this embodiment.

[0139] In this embodiment, liquid chlorine is mixed with initiator / solvent, chloromethane, and dichloromethane as feedstock, and an optimized distributor structure is designed to control the selectivity of carbon tetrachloride and reduce the proportion of carbon tetrachloride byproducts.

[0140] Example 4: A methane chloride production apparatus with adjustable product selectivity includes a chlorination reaction tower 5. The chlorination reaction tower 5 includes a gas phase outlet, which is sequentially connected to a primary condenser 6 and a secondary condenser 7. The chlorination reaction tower 5 also includes a liquid phase reflux port, and the liquid phase outlet of the secondary condenser 7 is connected to the liquid phase reflux port, which is used for at least heat transfer within the chlorination reaction tower 5. The primary condenser 6 and the secondary condenser 7 are connected in a manner where the gas phase outlet of the primary condenser 6 is connected to the inlet of the secondary condenser 7, or the liquid phase outlet of the primary condenser 6 is connected to the inlet of the secondary condenser 7, and these connections can be switched between each other. In other words, the connection method of the primary condenser 6 and the secondary condenser 7 can be arbitrarily selected from either the gas phase outlet of the primary condenser 6 connected to the inlet of the secondary condenser 7 or the liquid phase outlet of the primary condenser 6 connected to the inlet of the secondary condenser 7. Figure 4 This embodiment illustrates the connection method of the methane chloride production apparatus with adjustable product selectivity, where the gas phase outlet of the primary condenser 6 is connected to the inlet of the secondary condenser 7. The liquid phase output from the primary condenser 6 mixes with the liquid phase output from the chlorination reaction tower 5 to form the first chlorinated product 9. The gas phase outlet of the secondary condenser 7 discharges the second chlorinated product 8, which has a higher hydrogen chloride content than the first chlorinated product 9. The target product composition can be adjusted by changing the connection method between the primary condenser 6 and the secondary condenser 7, either connecting the gas phase outlet of the primary condenser 6 to the inlet of the secondary condenser 7 or connecting the liquid phase outlet of the primary condenser 6 to the inlet of the secondary condenser 7.

[0141] The liquid phase outlet or gas phase outlet of the first-stage condenser 6 is connected to the dehydrochlorination unit and can be switched between each other. That is, the liquid phase outlet and the gas phase outlet of the first-stage condenser 6 can be arbitrarily switched to connect to the dehydrochlorination unit according to the composition of the target product. For example: when reducing the selectivity of carbon tetrachloride, the gas phase outlet of the first-stage condenser 6 is connected to the inlet of the second-stage condenser 7, and the liquid phase outlet of the first-stage condenser 6 is connected to the dehydrochlorination unit; when increasing the selectivity of carbon tetrachloride, the liquid phase outlet of the first-stage condenser 6 is connected to the inlet of the second-stage condenser 7, and the gas phase outlet of the first-stage condenser 7 is connected to the dehydrochlorination unit.

[0142] A methane chloride production process with adjustable product selectivity, using the methane chloride production apparatus of this embodiment.

[0143] The gas phase outlet of the first-stage condenser 6 is connected to the inlet of the second-stage condenser 7, which can reduce the selectivity of carbon tetrachloride; the liquid phase outlet of the first-stage condenser 6 is connected to the inlet of the second-stage condenser 7, which can improve the selectivity of carbon tetrachloride.

[0144] Example 5: like Figure 5 As shown, a methane chloride production apparatus with adjustable product selectivity, without alkali washing and / or water washing devices, includes a chlorination reaction tower 5. The chlorination reaction tower 5 includes a chlorinated product outlet, which is sequentially connected to a high-pressure dehydrochlorination tower 10, a low-pressure dehydrochlorination tower 11, a monochloromethane tower 12, an acid flash evaporator 13, and a polychlorinated compound purification unit. The high-pressure dehydrochlorination tower 10, the low-pressure dehydrochlorination tower 11, and the acid flash evaporator 13 are used to remove at least the hydrogen chloride from the chlorinated product and / or the hydrogen chloride generated from the decomposition of the chlorinated product. The monochloromethane tower 12 is used at least to remove monochloromethane from the chlorinated product. The chlorination reaction tower 5, the high-pressure dehydrochlorination tower 10, the low-pressure dehydrochlorination tower 11, the monochloromethane tower 12, and the acid flash evaporator 13 are arranged with pressures following a pressure drop gradient.

[0145] The chlorinated product obtained after the chlorination reaction in chlorination tower 5 is discharged through the chlorinated product outlet and enters the dehydrochlorination high-pressure tower 10 to remove hydrogen chloride. Pure hydrogen chloride is collected from the top of the dehydrochlorination high-pressure tower 10, while the bottom contains high-boiling-point substances entrained with hydrogen chloride. These high-boiling-point substances entrained with hydrogen chloride enter the dehydrochlorination low-pressure tower 11 for further hydrogen chloride removal. The bottom of the dehydrochlorination low-pressure tower 11 contains high-boiling-point substances without hydrogen chloride, while the top contains hydrogen chloride entrained with high-boiling-point substances. The high-boiling-point substances without hydrogen chloride enter the monochloromethane tower 12 to remove monochloromethane. The material after monochloromethane removal enters the acid flash evaporator 13 for further removal of hydrogen chloride and other substances produced by the decomposition of the chlorination products. The resulting material can be directly sent to the polychlorinated compound purification unit 14 without alkaline washing / water washing.

[0146] The dehydrochlorination high-pressure tower 10 includes a first hydrogen chloride outlet, which is connected to a methanol chlorination unit 15. The methanol chlorination unit 15 is used at least for the chlorination reaction of methanol and hydrogen chloride to produce chloromethane.

[0147] The hydrogen chloride entrained with high-boiling substances at the top of the low-pressure dechlorination tower 11 is returned to the high-pressure dechlorination tower 10. The low-pressure dechlorination tower 11 includes a second hydrogen chloride outlet, which is connected to the high-pressure dechlorination tower 10. The high-pressure dechlorination tower 10 is used to separate the hydrogen chloride and high-boiling substances from the hydrogen chloride entrained with high-boiling substances discharged from the second hydrogen chloride outlet.

[0148] The monochloromethane tower 12 includes a monochloromethane outlet, which is connected to the chlorination reaction tower 5 to realize the recycling of monochloromethane.

[0149] The acid flash evaporator 13 includes a third hydrogen chloride outlet, which is connected to a methanol chlorination unit 15, which is used at least for the chlorination reaction of methanol and hydrogen chloride to produce chloromethane.

[0150] The composition of the materials recycled back to the chlorination reaction tower 5 from the high-pressure dechlorination tower 10 and / or the low-pressure dechlorination tower 11 and / or the monochloromethane tower 12, as well as the refining target of the polychlorinated compound refining unit 14, are adjustable. The composition of the target product can be adjusted by changing the composition of the materials recycled back to the chlorination reaction tower 5 from the high-pressure dechlorination tower 10 and / or the low-pressure dechlorination tower 11 and / or the monochloromethane tower 12, as well as the refining target of the polychlorinated compound refining unit 14.

[0151] A methane chloride production process with adjustable product selectivity, using the methane chloride production apparatus of this embodiment.

[0152] The methane chloride production unit and process in this embodiment are optimized as a whole system, making full use of energy and eliminating alkaline washing and water washing; a whole system circulation scheme is designed to achieve energy saving and consumption reduction and flexible control of the selectivity of products dichloromethane, trichloromethane and carbon tetrachloride.

[0153] Example 6: See Figures 1 to 5 In conjunction with Examples 1 to 5, a methane chloride production apparatus with adjustable product selectivity includes an alkali-free washing and / or water washing device, comprising a chlorination reaction tower 5 with a heat exchange coil inside. The chlorination reaction tower 5 includes a chlorinated product outlet, which is sequentially connected to a high-pressure dehydrochlorination tower 10, a low-pressure dehydrochlorination tower 11, a monochloromethane tower 12, an acid flash evaporator 13, and a polychlorinated compound purification unit. The high-pressure dehydrochlorination tower 10, the low-pressure dehydrochlorination tower 11, and the acid flash evaporator 13 are used at least to remove hydrogen chloride from the chlorinated product and / or to remove hydrogen chloride generated from the decomposition of the chlorinated product. The monochloromethane tower 12 is used at least to remove monochloromethane from the chlorinated product. The chlorination reaction tower 5, the high-pressure dehydrochlorination tower 10, the low-pressure dehydrochlorination tower 11, the monochloromethane tower 12, and the acid flash evaporator 13 are configured with pressures following a pressure drop gradient.

[0154] The chlorinated product obtained after the chlorination reaction in chlorination tower 5 is discharged through the chlorinated product outlet and enters the dehydrochlorination high-pressure tower 10 to remove hydrogen chloride. Pure hydrogen chloride is collected from the top of the dehydrochlorination high-pressure tower 10, while the bottom contains high-boiling-point substances entrained with hydrogen chloride. These high-boiling-point substances entrained with hydrogen chloride enter the dehydrochlorination low-pressure tower 11 for further hydrogen chloride removal. The bottom of the dehydrochlorination low-pressure tower 11 contains high-boiling-point substances without hydrogen chloride, while the top contains hydrogen chloride entrained with high-boiling-point substances. The high-boiling-point substances without hydrogen chloride enter the monochloromethane tower 12 to remove monochloromethane. The material after monochloromethane removal enters the acid flash evaporator 13 for further removal of hydrogen chloride and other substances produced by the decomposition of the chlorination products. The resulting material can be directly sent to the polychlorinated compound purification unit 14 without alkaline washing / water washing.

[0155] The dehydrochlorination high-pressure tower 10 includes a first hydrogen chloride outlet, which is connected to a methanol chlorination unit 15. The methanol chlorination unit 15 is used at least for the chlorination reaction of methanol and hydrogen chloride to produce chloromethane.

[0156] The hydrogen chloride entrained with high-boiling substances at the top of the low-pressure dechlorination tower 11 is returned to the high-pressure dechlorination tower 10. The low-pressure dechlorination tower 11 includes a second hydrogen chloride outlet, which is connected to the high-pressure dechlorination tower 10. The high-pressure dechlorination tower 10 is used to separate the hydrogen chloride and high-boiling substances from the hydrogen chloride entrained with high-boiling substances discharged from the second hydrogen chloride outlet.

[0157] The monochloromethane tower 12 includes a monochloromethane outlet, which is connected to the chlorination reaction tower 5 to realize the recycling of monochloromethane.

[0158] The acid flash evaporator 13 includes a third hydrogen chloride outlet, which is connected to a methanol chlorination unit 15, which is used at least for the chlorination reaction of methanol and hydrogen chloride to produce chloromethane.

[0159] The composition of the materials recycled back to the chlorination reaction tower 5 from the high-pressure dechlorination tower 10 and / or the low-pressure dechlorination tower 11 and / or the monochloromethane tower 12, as well as the refining target of the polychlorinated compound refining unit 14, are adjustable. The composition of the target product can be adjusted by changing the composition of the materials recycled back to the chlorination reaction tower 5 from the high-pressure dechlorination tower 10 and / or the low-pressure dechlorination tower 11 and / or the monochloromethane tower 12, as well as the refining target of the polychlorinated compound refining unit 14.

[0160] By optimizing the entire system and making full use of energy, the alkaline washing and water washing processes are eliminated; a system-wide circulation scheme is designed to achieve energy saving, consumption reduction, and flexible control of the selectivity of dichloromethane, trichloromethane, and carbon tetrachloride in the products.

[0161] The chlorination reaction tower 5 is connected to chlorine inlet 1, chloromethane inlet 2, dichloromethane inlet 3, and initiator / solvent inlet 4. The chlorine inlet 1 is connected to a gaseous chlorine pipeline 101 and a liquid chlorine pipeline 102. A gaseous chlorine regulating valve 103 is installed on the gaseous chlorine pipeline 101, and a liquid chlorine regulating valve 104 is installed on the gaseous chlorine pipeline 102. This design allows the chlorine feed form of the chlorine inlet 1 to be arbitrarily switched between gaseous, liquid, and gas-liquid mixed states. For example: when the chlorine feed form is gaseous, the liquid chlorine regulating valve 104 is closed and the gaseous chlorine regulating valve 103 is opened, and the gaseous chlorine pipeline 101 supplies gaseous chlorine to the chlorine inlet 1; when the chlorine feed form is liquid, the gaseous chlorine regulating valve 103 is closed and the liquid chlorine regulating valve 104 is opened, and the liquid chlorine pipeline 102 supplies liquid chlorine to the chlorine inlet 1; when the chlorine feed form is gas-liquid mixed state, the liquid chlorine regulating valve 104 and the gaseous chlorine regulating valve 103 are opened simultaneously, and the gaseous chlorine pipeline 101 and the liquid chlorine pipeline 102 simultaneously supply gaseous chlorine and liquid chlorine to the chlorine inlet 1, forming a gas-liquid mixed state. The opening degrees of the gaseous chlorine regulating valve 103 and the liquid chlorine regulating valve 104 are adjustable, thereby allowing adjustment of the ratio of gaseous chlorine to liquid chlorine in the gas-liquid mixture. The composition of the target product can be adjusted by changing the chlorine feed form to gas, liquid, or a gas-liquid mixture. Liquid chlorine feed can reduce carbon tetrachloride selectivity, gaseous chlorine feed can increase carbon tetrachloride selectivity, and chlorine feed in a gas-liquid mixture can achieve moderate carbon tetrachloride selectivity. By adjusting the chlorine feed form at the chlorine inlet, the selectivity of dichloromethane, trichloromethane, and carbon tetrachloride can be flexibly controlled according to different feed states, adapting flexibly to market changes.

[0162] Switching valves 105 are installed on the connecting pipelines of chlorine inlet 1, chloromethane inlet 2, dichloromethane inlet 3, and initiator / solvent inlet 4 to the chlorination reaction tower 5. By controlling the switching valves 105, the feeding method of each inlet can be controlled to either enter the chlorination reaction tower 5 independently or be mixed before entering. This design allows for arbitrary switching between two feeding methods: independent entry into the chlorine inlet 1, chloromethane inlet 2, dichloromethane inlet 3, and initiator / solvent inlet 4, and blending before entering the chlorination reaction tower 5. The composition of the target product can be adjusted by changing the feeding method of chlorine inlet 1, chloromethane inlet 2, dichloromethane inlet 3, and initiator / solvent inlet 4 to either enter the chlorination reaction tower 5 independently or be blended before entering. Chlorine inlet 1, chloromethane inlet 2, dichloromethane inlet 3, and initiator / solvent inlet 4 are fed into chlorination reaction tower 5 independently, which can improve the selectivity of carbon tetrachloride; chlorine inlet 1, chloromethane inlet 2, dichloromethane inlet 3, and initiator / solvent inlet 4 are fed into chlorination reaction tower 5 in a mixed manner, which can reduce the selectivity of carbon tetrachloride.

[0163] Furthermore, a topologically optimized mixing feed distributor is employed to achieve the blending. The mixing feed distributor includes a conical main structure 106, which can be installed inside the chlorination reaction tower 5. The conical main structure 106 includes a bottom annular pipe 107 and multiple evenly distributed connecting pipes 108 coinciding with the generatrix of the conical main structure 106. One end of each connecting pipe 108 is connected to the main feed pipe 109, and the other end is connected to the annular pipe 107. Chlorine inlet 1, chloromethane inlet 2, dichloromethane inlet 3, and initiator / solvent inlet 4 converge to the main feed pipe 109. Multiple outlet holes (not shown) are evenly distributed at the bottom of the annular pipe 107. By mixing liquid chlorine with the initiator / solvent, chloromethane, and dichloromethane, and designing an optimized distributor structure, the selectivity of carbon tetrachloride is controlled, and the proportion of carbon tetrachloride byproducts is reduced.

[0164] The chlorination reaction tower 5 includes a gas phase outlet, which is sequentially connected to a primary condenser 6 and a secondary condenser 7. The chlorination reaction tower 5 also includes a liquid phase reflux port, with the liquid phase outlet of the secondary condenser 7 connected to the liquid phase reflux port, serving at least for heat transfer within the chlorination reaction tower 5. The primary condenser 6 and the secondary condenser 7 are connected in a manner where either the gas phase outlet of the primary condenser 6 is connected to the inlet of the secondary condenser 7, or vice versa, and these connections can be switched. In other words, the connection method of the primary condenser 6 and the secondary condenser 7 can be arbitrarily selected between either the gas phase outlet of the primary condenser 6 connected to the inlet of the secondary condenser 7, or the liquid phase outlet of the primary condenser 6 connected to the inlet of the secondary condenser 7. The composition of the target product can be adjusted by changing the connection method of the primary condenser 6 and the secondary condenser 7, either by connecting the gas phase outlet of the primary condenser 6 to the inlet of the secondary condenser 7, or by connecting the liquid phase outlet of the primary condenser 6 to the inlet of the secondary condenser 7.

[0165] The liquid phase outlet or gas phase outlet of the first-stage condenser 6 is connected to the dehydrochlorination high-pressure tower 10 and can be switched between each other. That is, the liquid phase outlet and the gas phase outlet of the first-stage condenser 6 can be arbitrarily switched to connect to the dehydrochlorination high-pressure tower 10 according to the composition of the target product. For example: when reducing the selectivity of carbon tetrachloride, the gas phase outlet of the first-stage condenser 6 is connected to the inlet of the second-stage condenser 7, and the liquid phase outlet of the first-stage condenser 6 is connected to the dehydrochlorination high-pressure tower 10; when increasing the selectivity of carbon tetrachloride, the liquid phase outlet of the first-stage condenser 6 is connected to the inlet of the second-stage condenser 7, and the gas phase outlet of the first-stage condenser 7 is connected to the dehydrochlorination high-pressure tower 10.

[0166] The gas phase outlet of the first-stage condenser 6 is connected to the inlet of the second-stage condenser 7, which can reduce the selectivity of carbon tetrachloride; the liquid phase outlet of the first-stage condenser 6 is connected to the inlet of the second-stage condenser 7, which can improve the selectivity of carbon tetrachloride.

[0167] Figure 4This embodiment illustrates the connection between the gaseous outlet of the primary condenser 6 and the inlet of the secondary condenser 7 in a methane chloride production apparatus with adjustable product selectivity. The liquid phase output from the primary condenser 6 mixes with the liquid phase output from the chlorination reaction tower 5 to form the first chlorinated product 9. The gaseous outlet of the secondary condenser 7 discharges the second chlorinated product 8, which has a higher hydrogen chloride content than the first chlorinated product 9. Both the second chlorinated product 8 and the first chlorinated product 9 are sent to the hydrogen chloride high-pressure tower 10 to remove hydrogen chloride.

[0168] A methane chloride production process with adjustable product selectivity, using the methane chloride production apparatus of this embodiment.

[0169] Example 7: Dichloromethane was produced using the methane chloride production apparatus and process described in Example 6. The chlorination reaction pressure in the chlorination tower was 26 Bar, the operating pressure of the high-pressure dehydrochlorination tower was 20 Bar, the operating temperature of the high-pressure dehydrochlorination tower was 32°C, the operating pressure of the low-pressure dehydrochlorination tower was 5 Bar, the operating pressure of the monochloromethane tower was 4 Bar, and the operating pressure of the acid flash evaporator was negative, specifically 0.5 Bar. The gas phase outlet of the chlorination tower was sequentially connected to a primary condenser and a secondary condenser. The primary and secondary condensers were connected as follows: the gas phase outlet of the primary condenser was connected to the inlet of the secondary condenser, and the liquid phase outlet of the primary condenser was connected to the high-pressure dehydrochlorination tower. Liquid chlorine and liquid monochloromethane were used as raw materials, and azobisisobutyronitrile (AIBN) was used as the initiator. Figure 3 The distributor shown mixes the feed, and the reaction temperature is 105℃. After 72 hours of stable operation, the selectivity of dichloromethane, trichloromethane, and carbon tetrachloride in the final product was 75.3%, 23.2%, and 1.5%, respectively. The total circulating water flow rate of the heat exchange coils and two-stage condensers in the chlorination reaction tower was 50.6 m³. 3 / h.

[0170] Example 8: The system, apparatus, feed rate, and operating conditions were the same as in Example 7, except that gaseous chlorine was used as the feed. After 72 hours of stable operation, the selectivity of dichloromethane, trichloromethane, and carbon tetrachloride in the final product was 63.9%, 25.1%, and 11%, respectively. The total circulating water flow rate of the heat exchange coils and two-stage condensers in the chlorination reaction tower was 100.8 m³. 3 / h.

[0171] Example 9: The system, apparatus, feed rate, and operating conditions were the same as in Example 7, except that a mixed feed of gaseous and liquid chlorine (gas-liquid mass ratio 1:1) was used. After 72 hours of stable operation, the selectivity of dichloromethane, trichloromethane, and carbon tetrachloride in the final product was 68.2%, 24.6%, and 7.2%, respectively. The total circulating water flow rate of the heat exchange coils and two-stage condensers in the chlorination reaction tower was 75.3 m³.3 / h.

[0172] Example 10: The system, apparatus, feed rate, and operating conditions are the same as in Example 7, except that the following method is not used. Figure 3 The distributor shown is used for mixed feeding, and each inlet material is fed separately. After stable operation for 72 hours, the selectivity of dichloromethane, trichloromethane, and carbon tetrachloride in the final product is 73.8%, 23.1%, and 3.1%, respectively. The total flow rate of circulating water in the heat exchange coils and two-stage condensers of the chlorination reaction tower is 51.5 m³. 3 / h.

[0173] Examples 7, 8, and 9 demonstrate that the apparatus and process of the present invention can flexibly adjust product selectivity by controlling the chlorine feed state, and that the use of liquid chlorine significantly reduces the heat transfer energy consumption of the reactor.

[0174] Examples 7 and 10 demonstrate that the mixed feed of the present invention can significantly improve the selectivity of the main reaction and reduce the selectivity of chloroform and carbon tetrachloride byproducts.

[0175] Examples 7-10 together illustrate that the high-efficiency device and process proposed in this invention can operate stably and achieve energy conservation and emission reduction.

[0176] Example 11: Trichloromethane was produced using the methane chloride production apparatus and process described in Example 6. The chlorination reaction pressure in the chlorination tower was 26 Bar, the operating pressure of the high-pressure dehydrochlorination tower was 22 Bar, the operating temperature of the high-pressure dehydrochlorination tower was 32°C, the operating pressure of the low-pressure dehydrochlorination tower was 10 Bar, the operating pressure of the monochloromethane tower was 5 Bar, and the operating pressure of the acid flash evaporator was negative, specifically 0.7 Bar. The gas phase outlet of the chlorination tower was sequentially connected to a primary condenser and a secondary condenser. The primary and secondary condensers were connected as follows: the gas phase outlet of the primary condenser was connected to the inlet of the secondary condenser, and the liquid phase outlet of the primary condenser was connected to the high-pressure dehydrochlorination tower. Liquid chlorine and liquid monochloromethane were used as raw materials, dichloromethane was completely recycled, and azobisisobutyronitrile (AIOBR) was used as the initiator. The materials passed through… Figure 3 The distributor shown mixes the feed, and the reaction temperature is 105°C. After 72 hours of stable operation, the selectivity of chloroform and carbon tetrachloride in the final product is 94.8% and 5.2%, respectively.

[0177] Example 12: The system, apparatus, feed rate, and operating conditions were the same as in Example 11, except that each inlet material was fed separately. The system and apparatus operated stably for 72 hours, and the selectivity of chloroform and carbon tetrachloride in the final product was 93.1% and 6.9%, respectively.

[0178] Example 13: The system, apparatus, feed rate, and operating conditions were the same as in Example 11, except that chlorine was fed in a gaseous state. The system and apparatus operated stably for 72 hours, and the selectivity of chloroform and carbon tetrachloride in the final product was 82.6% and 17.4%, respectively.

[0179] Examples 11-13 illustrate that the efficient apparatus and process for producing trichloromethane as the target product of the present invention can operate stably, save energy and reduce emissions, and achieve the goal of high production of trichloromethane while low production of carbon tetrachloride.

[0180] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A process for producing methane chloride, characterized in that, A chlorination reaction tower is used, which is connected to a chlorine inlet, a chloromethane inlet, and an initiator / solvent inlet. The chlorine inlet, chloromethane inlet, and initiator / solvent inlet are fed into the chlorination reaction tower after being mixed. The chlorine gas is fed in liquid form, and the main component of the target product is dichloromethane, with carbon tetrachloride accounting for less than 5% based on the total mass of dichloromethane, trichloromethane, and carbon tetrachloride as 100%. The blending is achieved using a topology-optimized mixing feed distributor. The mixing feed distributor includes a conical main structure, which comprises a bottom annular tube and multiple evenly distributed connecting tubes coinciding with the generatrix of the conical main structure. One end of each connecting tube is connected to the main feed pipe, and the other end is connected to the annular tube. A chlorine inlet, a chloromethane inlet, and an initiator / solvent inlet converge to the main feed pipe. Multiple outlet holes are evenly distributed at the bottom of the annular tube. The chlorination reaction tower includes a gas phase outlet, which is connected in sequence to a primary condenser and a secondary condenser. The gas phase outlet of the primary condenser is connected to the inlet of the secondary condenser. The chlorination reaction temperature inside the chlorination reaction tower is 70~120℃; The chlorination reaction tower includes a liquid phase reflux port, and the liquid phase outlet of the secondary condenser is connected to the liquid phase reflux port, which is used at least for heat removal within the chlorination reaction tower; The liquid phase outlet of the primary condenser is connected to a hydrogen chloride removal unit. The vapor phase outlet of the secondary condenser is connected to a hydrogen chloride removal unit. The chlorination reaction tower includes a chlorination product outlet, which is sequentially connected to a high-pressure dehydrochlorination tower, a low-pressure dehydrochlorination tower, a chloromethane tower, and an acid flash evaporator. The high-pressure dechlorination tower, the low-pressure dechlorination tower, and the acid flash evaporator are at least used to remove hydrogen chloride from the chlorination products and / or remove hydrogen chloride generated from the decomposition of the chlorination products. The monochloromethane tower is used at least to remove monochloromethane from the chlorination products; The chlorination reaction tower, the high-pressure dehydrochlorination tower, the low-pressure dehydrochlorination tower, the monochloromethane tower, and the acid flash evaporator are set with pressures following the pressure drop gradient. The chlorination reaction pressure inside the chlorination reaction tower is 10~50 bar.

2. The methane chloride production process according to claim 1, characterized in that, The chlorination reaction temperature inside the chlorination reaction tower is 100~115℃.

3. The methane chloride production process according to claim 1, characterized in that, The chlorination reaction pressure inside the chlorination reaction tower is 25~30 bar.

4. The methane chloride production process according to claim 1, characterized in that, The operating pressure of the hydrogen chloride removal high-pressure tower is 5~40 bar.

5. The methane chloride production process according to claim 4, characterized in that, The operating pressure of the dehydrochlorination high-pressure tower is 10~20 bar.

6. The methane chloride production process according to claim 1, characterized in that, The operating temperature of the hydrogen chloride removal high-pressure tower is above 0°C.

7. The methane chloride production process according to claim 1, characterized in that, The operating pressure of the dehydrochlorination low-pressure tower is 1~15 bar.

8. The methane chloride production process according to claim 7, characterized in that, The operating pressure of the dehydrochlorination low-pressure tower is 5~10 bar.

9. The methane chloride production process according to claim 1, characterized in that, The operating pressure of the monochloromethane tower is 0.5~10 bar.

10. The methane chloride production process according to claim 9, characterized in that, The operating pressure of the monochloromethane tower is 0.5~5 bar.

11. The methane chloride production process according to claim 1, characterized in that, The working pressure of the acid flash evaporator is 0.1~2 bar.

12. The methane chloride production process according to claim 11, characterized in that, The working pressure of the acid flash evaporator is 0.2~1 bar.

13. The methane chloride production process according to claim 1, characterized in that, The working pressure of the acid flash evaporator is negative.

14. The methane chloride production process according to claim 1, characterized in that, The methane chloride production process does not involve alkali washing and / or water washing.

15. The methane chloride production process according to claim 1, characterized in that, The dehydrochlorination high-pressure tower includes a first hydrogen chloride outlet, which is connected to a methanol chlorination unit. The methanol chlorination unit is used at least for the chlorination reaction of methanol and hydrogen chloride to produce chloromethane.

16. The methane chloride production process according to claim 1, characterized in that, The dehydrochlorination low-pressure tower includes a second hydrogen chloride outlet, which is connected to the dehydrochlorination high-pressure tower. The dehydrochlorination high-pressure tower is used to separate hydrogen chloride and high-boiling substances from the hydrogen chloride containing high-boiling substances discharged from the second hydrogen chloride outlet.

17. The methane chloride production process according to claim 1, characterized in that, The monochloromethane tower includes a monochloromethane outlet, which is connected to the chlorination reaction tower to achieve the recycling of monochloromethane.

18. The methane chloride production process according to claim 1, characterized in that, The acid flash evaporator includes a third hydrogen chloride outlet, which is connected to a methanol chlorination unit. The methanol chlorination unit is used at least for the chlorination reaction of methanol and hydrogen chloride to produce chloromethane.

Images