Cold recovery system and process in hydrogen chloride and acetylene gas dehydration process

Abstract

The present disclosure relates to a polyvinyl chloride production process, and specifically provides a system and process for recovering cold in a hydrogen chloride and acetylene gas dehydration process. It comprises a mixing unit, a deep cooling deacidification unit and a heat exchange unit in sequence; the mixing unit comprises an acetylene cooler, a hydrogen chloride cooler and a mixer, the mixer mixes the acetylene in the acetylene cooler with the hydrogen chloride in the hydrogen chloride cooler, and transports the mixture to the deep cooling deacidification unit; the deep cooling deacidification unit comprises a graphite cooler and an acid mist collector. The heat exchange unit heats the gas mixture at the outlet of the deep cooling deacidification unit, and the heat exchange unit is divided into a primary heat exchange unit and a secondary heat exchange unit. The problem that the cold collection in the polyvinyl chloride production process in the prior art cannot be applied to actual industrial production is solved.

Description

Technical Field

[0001] The present invention relates to a polyvinyl chloride production process, and specifically provides a system and process for recovering cold in a hydrogen chloride and acetylene gas dehydration process. Background Art

[0002] The statements herein merely provide background information related to the present disclosure and may not necessarily constitute prior art.

[0003] Polyvinyl chloride is the world's largest-volume general-purpose plastic with a wide range of applications. It is widely used in building materials, industrial products, daily necessities, floor coverings, floor tiles, artificial leather, pipes, wires and cables, packaging films, bottles, foaming materials, sealing materials, fibers, etc. In the prior art, other ingredients are often added to enhance its heat resistance, toughness, ductility, etc. It is a popular and widely used synthetic material in the world today. Its global usage ranks second among various synthetic materials.

[0004] With the development of my country's industry, the domestic production of polyvinyl chloride has increased dramatically. The commonly used process is to preliminarily cool acetylene and hydrogen chloride gas and mix them, then cool them in a deep cooling deacidification system, and after deacidification in an acid mist collector, send them to a hot water preheater for heating, synthesize vinyl chloride monomer in a converter, and polymerize the monomer to generate polyvinyl chloride. The production of vinyl chloride monomer consumes a lot of energy, especially a large amount of cold energy is consumed during the gas cooling process, and a large amount of heat is consumed during the heating process. For this reason, the present invention uses the cold energy of the mixed gas after deep cooling deacidification to preliminarily cool acetylene and hydrogen chloride gas. The prior art provides an energy-saving device for dehydrating acetylene and hydrogen chloride mixed gas in polyvinyl chloride production. However, the inventor found that on the one hand, because the total heat transfer coefficient of gas-to-gas heat exchange is about 10 to 50 W / (m 2 ·℃), the heat exchange coefficient is low. If gas-to-gas heat exchange is used in the prior art, a larger heat exchanger is required to meet the heat exchange requirements, and the mixed gas pipeline is thicker and the investment is higher. When the original device is modified, the larger size of the heat exchanger and pipeline makes it difficult to install the equipment and pipe, or even impossible to install. On the other hand, the mixed gas pressure is low, and an additional fan is required for pressurization, which increases power consumption. In addition, the mixed gas contains hydrogen chloride and acetylene, which requires acid-resistant and explosion-proof fans. The fan investment is high and the selection is difficult, which cannot be applied to normal production. Summary of the invention

[0005] In the prior art, hydrogen chloride and acetylene gases are first cooled with 7°C cold water, and then the mixed gas is heated with hot water after deep cooling and deacidification. This process does not optimize the heat exchange network, and the use of cold and heat is unreasonable, resulting in a huge waste of energy. On the other hand, the low-temperature mixed gas after deep cooling and deacidification is directly sent to the hot water preheater for heating. Due to the large temperature difference experienced by the equipment, it is not conducive to the long-term operation of the equipment.

[0006] In one or some embodiments of the present disclosure, a cold recovery and utilization system in a hydrogen chloride and acetylene gas dehydration process is provided, comprising a mixing unit, a deep cooling deacidification unit and a heat exchange unit connected in sequence;

[0007] The mixing unit comprises an acetylene cooler, a hydrogen chloride cooler and a mixer. The mixer mixes the acetylene in the acetylene cooler with the hydrogen chloride in the hydrogen chloride cooler and transports the mixture to a deep cooling deacidification unit. The cold medium in the acetylene cooler and the hydrogen chloride cooler is an ethylene glycol solution.

[0008] The deep cooling deacidification unit comprises a graphite cooler and an acid mist collector. The acid mist collector is used to remove hydrochloric acid mist in the mixture. The cold medium in the graphite cooler is frozen brine.

[0009] The heat exchange unit heats the gas mixture at the outlet of the deep cooling deacidification unit. The heat exchange unit is divided into a primary heat exchange unit and a secondary heat exchange unit. The primary heat exchange unit preliminarily heats the mixture, and the secondary heat exchange unit heats the mixture to the final temperature. The heat medium in the primary heat exchange unit comes from the cold medium that has undergone heat exchange in the acetylene cooler and the hydrogen chloride cooler.

[0010] In one or some embodiments of the present disclosure, a cold recovery and utilization process in a hydrogen chloride and acetylene gas dehydration process is provided, comprising the following steps: acetylene and hydrogen chloride are cooled separately, and after cooling, they are mixed into a mixture in a mixer, the mixed mixture is entered into a deep cooling deacidification unit for deacidification treatment, the mixture after deep cooling deacidification enters a heat exchange unit for heat exchange, the heat exchange unit heats the mixture and then discharges the material, and the heat medium in the heat exchange unit comes from the cold medium after the acetylene and hydrogen chloride are cooled and heat exchanged.

[0011] One or some of the above technical solutions have the following advantages or beneficial effects:

[0012] 1) The present invention optimizes the heat exchange process, performs heat exchange between the mixed gas after deep cooling and deacidification and hydrogen chloride and acetylene gas, and adopts ethylene glycol aqueous solution as the heat exchange medium. After the ethylene glycol aqueous solution and the mixed gas after deep cooling and deacidification are heat exchanged, they are respectively transported to the acetylene cooler and the hydrogen chloride cooler for cooling the acetylene and hydrogen chloride, thereby reducing energy consumption.

[0013] 2) While improving the process, the present disclosure re-planned the applicable temperature of the process due to the change in process conditions. The planned temperature makes it just right for the cold and hot media to not need external heat exchange, and completely realizes self-circulation. After the process is improved, the water content in the acetylene gas is reduced, thereby reducing the output of waste acid in the deep cold deacidification system and saving the cost of waste acid treatment.

[0014] 3) The present disclosure can reduce the temperature difference variation suffered by the primary graphite heat exchanger, thereby allowing the equipment to operate for a long period of time. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure.

[0016] Figure 1 This is a production process flow chart implemented before the modification of the present disclosure.

[0017] Figure 2 The present invention is a production process flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present disclosure are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of them. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0019] In the prior art, when the low-temperature mixed gas after deep cooling and deacidification is directly sent to the hot water preheater for heating, not only the cooling capacity is wasted, but also a large amount of heat energy is required to heat the low-temperature mixed gas to the set temperature, which consumes a lot of energy. In the prior art, gas-to-gas heat exchange is adopted. Due to the small heat exchange coefficient between gas and gas, the heat exchanger is too large, the mixed gas pipeline is thick, the investment is large, the piping is difficult, and the mixed gas pressure is low, and a fan is required for pressurization. The mixed gas is highly corrosive, which causes corrosion to the heat exchanger wall.

[0020] In one or some embodiments of the present disclosure, a cold recovery and utilization system in a hydrogen chloride and acetylene gas dehydration process is provided, comprising a mixing unit, a deep cooling deacidification unit and a heat exchange unit connected in sequence;

[0021] The mixing unit comprises an acetylene cooler, a hydrogen chloride cooler and a mixer. The mixer mixes the acetylene in the acetylene cooler with the hydrogen chloride in the hydrogen chloride cooler and transports the mixture to a deep cooling deacidification unit. The cold medium in the acetylene cooler and the hydrogen chloride cooler is an ethylene glycol solution.

[0022] The deep cooling deacidification unit comprises a graphite cooler and an acid mist collector. The acid mist collector is used to remove hydrochloric acid mist in the mixture. The cold medium in the graphite cooler is frozen brine.

[0023] The heat exchange unit heats the gas mixture at the outlet of the deep cooling deacidification unit. The heat exchange unit is divided into a primary heat exchange unit and a secondary heat exchange unit. The primary heat exchange unit preliminarily heats the mixture, and the secondary heat exchange unit heats the mixture to the final temperature. The heat medium in the primary heat exchange unit comes from the cold medium that has undergone heat exchange in the acetylene cooler and the hydrogen chloride cooler.

[0024] The present invention optimizes the heat exchange process, performs heat exchange between the mixed gas after deep cooling and deacidification and hydrogen chloride and acetylene gas, adopts ethylene glycol aqueous solution as the heat exchange medium, and after the ethylene glycol aqueous solution and the mixed gas after deep cooling and deacidification are heat exchanged, they are respectively transported to the acetylene cooler and the hydrogen chloride cooler for cooling the acetylene and hydrogen chloride, thereby reducing energy consumption.

[0025] Preferably, the cooling medium in the acetylene cooler and the hydrogen chloride cooler is ethylene glycol. The total heat transfer coefficient of gas-to-gas heat exchange is about 10 to 50 W / (m 2 ·℃), the total heat transfer coefficient of gas and water is about 20~300W / (m 2 ·℃), it is obvious that the gas-liquid heat transfer coefficient is much greater than the heat transfer coefficient between gases. The present disclosure adopts ethylene glycol aqueous solution to exchange heat with gas, which is similar to the total heat transfer coefficient of cold water and gas in the existing process. The heat exchanger can use the original heat exchanger after calculation and verification, and the pipeline can also use the original pipeline. There is no need to replace equipment and pipelines, and the transformation is simple with low investment.

[0026] Moreover, ethylene glycol solution is a commonly used antifreeze solution in industry and is easily available.

[0027] Preferably, the primary heat exchange unit is a primary graphite heat exchanger and an ethylene glycol solution storage tank, the ethylene glycol solution storage tank provides heat medium for the primary graphite heat exchanger, the primary graphite heat exchanger is connected to the deep cooling deacidification unit, and the ethylene glycol solution storage tank is respectively connected to the cold medium outlets of the acetylene cooler and the hydrogen chloride cooler.

[0028] The present invention replaces the steel preheater in the existing process with a graphite preheater to prevent the mixed gas after deep cooling and deacidification from carrying trace amounts of hydrogen chloride and causing corrosion to the equipment.

[0029] Two circulating pumps are added between the primary graphite heat exchanger and the ethylene glycol solution storage tank, one for operation and one for standby. The ethylene glycol solution from the storage tank and the mixed gas after deep cooling and deacidification are heat exchanged in the primary graphite heat exchanger.

[0030] Preferably, the hot medium outlet of the primary graphite heat exchanger is connected to the cold medium inlet of the acetylene cooler and the hydrogen chloride cooler respectively.

[0031] Preferably, the secondary heat exchange unit is a secondary graphite heat exchanger, the mixture after preliminary preheating enters the secondary graphite heat exchanger, and the heat medium in the secondary graphite heat exchanger is hot water.

[0032] Preferably, the heat exchange unit is also connected to the converter.

[0033] In one or some embodiments of the present disclosure, a cold recovery and utilization process in a hydrogen chloride and acetylene gas dehydration process is provided, comprising the following steps: acetylene and hydrogen chloride are cooled separately, and after cooling, they are mixed into a mixture in a mixer, the mixed mixture is entered into a deep cooling deacidification unit for deacidification treatment, the mixture after deep cooling deacidification enters a heat exchange unit for heat exchange, the heat exchange unit heats the mixture and then discharges the material, and the heat medium in the heat exchange unit comes from the cold medium after the acetylene and hydrogen chloride are cooled and heat exchanged.

[0034] Preferably, the cold medium is an ethylene glycol solution, and the temperature of the ethylene glycol solution when entering the acetylene cooler and the hydrogen chloride cooler is 2-5°C, preferably 3°C;

[0035] Preferably, the temperature of the ethylene glycol solution after heat exchange from the acetylene cooler and the hydrogen chloride cooler is 18-25°C, preferably 20°C;

[0036] Preferably, the initial temperature of the acetylene and hydrogen chloride entering the cooler is 25-35°C, preferably 30°C.

[0037] Preferably, the temperature of the acetylene and hydrogen chloride after cooling is 10-15°C, preferably 12°C;

[0038] The temperature of the acetylene and hydrogen chloride mixture after deep cooling and deacidification is -20 to -8°C, preferably -12°C.

[0039] Preferably, the method further comprises a medium circulation step: using the hot medium after heat exchange in the heat exchange unit as a cold medium in the cooling process of acetylene and hydrogen chloride.

[0040] Preferably, the heat exchange is carried out in two steps. The heat exchange medium in the first step is the cold medium after cooling and heat exchange between acetylene and hydrogen chloride. The temperature of the mixture after heat exchange is 10-20°C, preferably 15°C. The heat exchange medium in the second step is hot water. The temperature of the mixture after heat exchange is 75-90°C, more preferably 80°C. Preferably, the temperature of the hot water is 90-100°C, more preferably 95°C.

[0041] Hydrogen chloride and acetylene gas are first preliminarily cooled. The lower the gas cooling temperature, the lower the water content in the gas, which reduces the load of the deep cold deacidification system and reduces the amount of frozen brine used. The scheme in the comparative example of the present disclosure is limited by the cold water temperature (7°C) and the heat exchange area of ​​the heat exchanger, and the outlet temperature of hydrogen chloride and acetylene gas cannot be further reduced. The present disclosure uses an ethylene glycol aqueous solution with a temperature of 3°C (if it is below 0°C, the water in the gas may freeze and block the pipeline; this technology uses 3°C to avoid the freezing of water in hydrogen chloride and acetylene gas), which can further reduce the outlet temperature of hydrogen chloride and acetylene gas to 12°C, so that the cold capacity in the system can be fully recycled and utilized, reducing energy consumption. On the other hand, the water content in acetylene gas is reduced, which reduces the output of waste acid in the deep cold deacidification system and saves the cost of waste acid treatment.

[0042] In addition, in the comparative example, the primary graphite heat exchanger is heated by 95°C hot water, and the outlet temperature of the mixed gas is 70°C; the present technology uses 20°C ethylene glycol aqueous solution for heat exchange, and the outlet temperature of the mixed gas is 15°C. Due to the change in process conditions, the original temperature cannot be used. The present disclosure can reduce the temperature difference change suffered by the primary graphite heat exchanger, so that the equipment can operate for a long period of time.

[0043] Example 1

[0044] This embodiment provides a cold recovery and utilization system in a hydrogen chloride and acetylene gas dehydration process, comprising a mixing unit, a deep cooling deacidification unit, a heat exchange unit and a converter connected in sequence;

[0045] The mixing unit comprises an acetylene cooler, a hydrogen chloride cooler and a mixer. The mixer mixes the acetylene in the acetylene cooler with the hydrogen chloride in the hydrogen chloride cooler and transports the mixture to a deep cooling deacidification unit. The cold medium in the acetylene cooler and the hydrogen chloride cooler is an ethylene glycol solution.

[0046] The deep cooling deacidification unit comprises a graphite cooler and an acid mist collector. The acid mist collector is used to remove hydrochloric acid mist in the mixture. The cold medium in the graphite cooler is frozen brine.

[0047] The heat exchange unit heats the gas mixture at the outlet of the deep cold deacidification unit. The heat exchange unit includes a primary graphite heat exchanger and a secondary graphite heat exchanger. The primary graphite heat exchanger preliminarily heats the mixture, and the secondary graphite heat exchanger heats the mixture to the final temperature. The heat medium in the primary graphite heat exchanger comes from the cold medium that has undergone heat exchange in the acetylene cooler and the hydrogen chloride cooler. The heat medium in the secondary graphite heat exchanger is hot water.

[0048] The primary graphite heat exchanger is also connected to an ethylene glycol solution storage tank, and the ethylene glycol solution storage tank is respectively connected to the cooling medium outlets of the acetylene cooler and the hydrogen chloride cooler.

[0049] The primary graphite heat exchanger is connected to the deep cooling deacidification unit.

[0050] Example 2

[0051] like Figure 2 As shown, this embodiment provides a cold recovery and utilization process in the hydrogen chloride and acetylene gas dehydration process. The process is carried out in the cold recovery and utilization system in the hydrogen chloride and acetylene gas dehydration process described in Example 1, and includes the following steps:

[0052] Acetylene and hydrogen chloride at 30°C are cooled separately in a cooler, the medium in the cooler is ethylene glycol at 3°C, the acetylene and hydrogen chloride after cooling are both 12°C, and after cooling, they enter a mixer to be mixed into a mixture, and the mixed mixture enters a deep cooling deacidification unit for deacidification treatment, the mixture after deep cooling deacidification is -12°C, and then enters a heat exchange unit for heat exchange, and the heat exchange is carried out in two steps. The first step of heat exchange is carried out in a primary graphite heat exchanger, and the temperature of the mixture after heat exchange is 15°C, and the second step of heat exchange is carried out in a secondary graphite heat exchanger, and the temperature of the mixture after heat exchange is 80°C, and the temperature of hot water is 95°C.

[0053] Example 3

[0054] like Figure 2 As shown, this embodiment provides a cold recovery and utilization process in the hydrogen chloride and acetylene gas dehydration process. The process is carried out in the cold recovery and utilization system in the hydrogen chloride and acetylene gas dehydration process described in Example 1, and includes the following steps:

[0055] Acetylene and hydrogen chloride at 30°C are cooled separately in a cooler, the medium in the cooler is ethylene glycol at 5°C, the acetylene and hydrogen chloride after cooling are both 10°C, and after cooling, they enter the mixer to be mixed into a mixture, and the mixed mixture enters the deep cooling deacidification unit for deacidification treatment, the mixture after deep cooling deacidification is -15°C, and then enters the heat exchange unit for heat exchange, and the heat exchange is carried out in two steps. The first step of heat exchange is carried out in a primary graphite heat exchanger, and the temperature of the mixture after heat exchange is 10°C, and the second step of heat exchange is carried out in a secondary graphite heat exchanger, and the temperature of the mixture after heat exchange is 85°C, and the temperature of hot water is 95°C.

[0056] Comparative Example 1

[0057] like Figure 1As shown in the figure, in the polyvinyl chloride synthesis conversion process, the temperature of acetylene and hydrogen chloride gas from outside the boundary area is 30℃, and they are cooled to 18℃ respectively with 7℃ cold water for preliminary dehydration. After preliminary dehydration, they enter the mixer for mixing, and then enter the deep cooling deacidification system for heat exchange with -35℃ frozen brine. The strong water absorption of hydrogen chloride is used to fully remove the moisture in the mixed gas. The temperature of the mixed gas after deep cooling is -12℃, and it enters the first-level graphite heat exchanger to heat exchange with 95℃ hot water to 70℃, and then enters the steel preheater to heat exchange with 95℃ hot water to above 80℃, and finally enters the converter for conversion reaction.

[0058] From the process of comparative example 1, the mixed gas entering the boundary zone is first cooled with 7°C cold water for preliminary dehydration, and the mixed gas after deep cooling and deacidification (-12°C) is then heated with hot water. In this process, the heat exchange network is not optimized, and the use of cold and heat is unreasonable, resulting in a huge waste of energy.

[0059] Through the transformation of Examples 1-3, the new process no longer uses 7°C cold water and reduces the use of hot water. The company can save more than 1 million yuan in electricity costs each year.

[0060] The above disclosure is only the preferred embodiment of the present disclosure, which certainly cannot be used to limit the scope of rights of the present disclosure. Therefore, equivalent changes made according to the scope of the patent application of the present disclosure are still within the scope covered by the present disclosure.

Claims

1. A system for recovering cold energy in a hydrogen chloride and acetylene gas dehydration process, characterized in that: It includes a mixing unit, a deep cooling deacidification unit and a heat exchange unit connected in sequence; The mixing unit comprises an acetylene cooler, a hydrogen chloride cooler and a mixer. The mixer mixes the acetylene in the acetylene cooler with the hydrogen chloride in the hydrogen chloride cooler and transports the mixture to a deep cooling deacidification unit. The cold medium in the acetylene cooler and the hydrogen chloride cooler is an ethylene glycol solution. The deep cooling deacidification unit comprises a graphite cooler and an acid mist collector, wherein the acid mist collector is used to remove hydrochloric acid mist in the mixture, and the cold medium in the graphite cooler is frozen brine; The heat exchange unit heats the gas mixture at the outlet of the deep cooling deacidification unit. The heat exchange unit is divided into a primary heat exchange unit and a secondary heat exchange unit. The primary heat exchange unit preliminarily heats the mixture, and the secondary heat exchange unit heats the mixture to the final temperature. The heat medium in the primary heat exchange unit comes from the cold medium that has undergone heat exchange in the acetylene cooler and the hydrogen chloride cooler. The cooling medium in the acetylene cooler and the hydrogen chloride cooler is ethylene glycol solution; The cold medium in the deep cooling deacidification unit is frozen brine; The primary heat exchange unit is a primary graphite heat exchanger and an ethylene glycol solution storage tank, the ethylene glycol solution storage tank provides heat medium for the primary graphite heat exchanger, the primary graphite heat exchanger is connected to a deep cooling deacidification unit, and the ethylene glycol solution storage tank is respectively connected to the cold medium outlets of the acetylene cooler and the hydrogen chloride cooler; The heat exchange unit is also connected to the converter.

2. The cold recovery and utilization system in the hydrogen chloride and acetylene gas dehydration process according to claim 1, characterized in that: The hot medium outlet of the primary graphite heat exchanger is connected to the cold medium inlet of the acetylene cooler and the hydrogen chloride cooler respectively.

3. The cold recovery and utilization system in the hydrogen chloride and acetylene gas dehydration process according to claim 1, characterized in that: The secondary heat exchange unit is a secondary graphite heat exchanger. The mixture after preliminary preheating enters the secondary graphite heat exchanger, and the heat medium in the secondary graphite heat exchanger is hot water.

4. A process for recovering cold from a hydrogen chloride or acetylene gas dehydration process based on the system for recovering cold from a hydrogen chloride or acetylene gas dehydration process according to claim 1, characterized in that: The method comprises the following steps: cooling acetylene and hydrogen chloride respectively, and mixing them into a mixture in a mixer after cooling; the mixed mixture enters a deep cooling deacidification unit for deacidification treatment; the mixture after deep cooling deacidification enters a heat exchange unit for heat exchange; the heat exchange unit heats the mixture and then discharges the mixture; the heat medium in the heat exchange unit comes from the cold medium after the acetylene and hydrogen chloride are cooled and heat exchanged.

5. The cold recovery and utilization process in the hydrogen chloride and acetylene gas dehydration process according to claim 4, characterized in that: The cold medium is an ethylene glycol solution, and the temperature of the ethylene glycol solution when entering the acetylene cooler and the hydrogen chloride cooler is 2-5°C.

6. The cold recovery and utilization process in the hydrogen chloride and acetylene gas dehydration process according to claim 5, characterized in that: The temperature of the ethylene glycol solution when entering the acetylene cooler and the hydrogen chloride cooler is 3°C.

7. The cold recovery and utilization process in the hydrogen chloride and acetylene gas dehydration process according to claim 4, characterized in that: The temperature of the ethylene glycol after heat exchange from the acetylene cooler and the hydrogen chloride cooler is 18-25°C; The initial temperature of the acetylene and hydrogen chloride entering the cooler is 25-35°C.

8. The cold recovery and utilization process in the hydrogen chloride and acetylene gas dehydration process according to claim 7, characterized in that: The temperature of the ethylene glycol after heat exchange from the acetylene cooler and the hydrogen chloride cooler is 20°C; The initial temperature of the acetylene and hydrogen chloride entering the cooler is 30°C.

9. The cold recovery and utilization process in the hydrogen chloride and acetylene gas dehydration process according to claim 4, characterized in that: The temperature of the acetylene and hydrogen chloride after cooling is 10-15°C; The temperature of the acetylene and hydrogen chloride after deep cooling and deacidification is -20~-8°C.

10. The cold recovery and utilization process in the hydrogen chloride and acetylene gas dehydration process according to claim 9, characterized in that: The temperature of the acetylene and hydrogen chloride after entering the cooling is 12°C; The temperature of the acetylene and hydrogen chloride after deep cooling and deacidification is -12°C.

11. The cold recovery and utilization process in the hydrogen chloride and acetylene gas dehydration process according to claim 4, characterized in that: The method also includes a medium circulation step: using the hot medium after heat exchange in the heat exchange unit as a cold medium in the cooling process of acetylene and hydrogen chloride.

12. The cold recovery and utilization process in the hydrogen chloride and acetylene gas dehydration process according to claim 4, characterized in that: The heat exchange is carried out in two steps. The first step heat exchange medium comes from the cold medium after the cooling and heat exchange of acetylene and hydrogen chloride. The temperature of the mixture after the heat exchange is 10-20°C. The second step heat exchange medium is hot water. The temperature of the mixture after the heat exchange is 75-90°C, and the temperature of the hot water is 90-100°C.

13. The cold recovery and utilization process in the hydrogen chloride and acetylene gas dehydration process according to claim 12, characterized in that: The temperature of the mixture after the first step of heat exchange is 15°C, the temperature of the mixture after the second step of heat exchange is 80°C, and the temperature of the hot water is 95°C.

Images