Production system of food-grade hydrochloric acid

Abstract

The utility model provides a production system of food-grade hydrochloric acid. The system comprises a vinyl chloride production device, a pressure swing adsorption device, an electrolysis device, a washing tower, a hydrogen buffer tank, a chlorine buffer tank, a liquid chlorine compression device, a hydrogen chloride synthesis furnace and a hydrogen chloride falling film absorber. An outlet of the vinyl chloride production device is connected with the pressure swing adsorption device, a hydrogen outlet of the pressure swing adsorption device is connected with the hydrogen buffer tank, a hydrogen outlet of the electrolysis device is connected with a gas inlet of the washing tower, and an outlet of the washing tower is connected with the hydrogen buffer tank. A tail gas outlet of the liquid chlorine compression device is connected with the chlorine buffer tank, outlets of the hydrogen buffer tank and the chlorine buffer tank are connected with a gas inlet of the hydrogen chloride synthesis furnace, and a gas outlet of the hydrogen chloride synthesis furnace is connected with the hydrogen chloride falling film absorber. According to the invention, efficient production of food-grade hydrochloric acid is realized.

Description

Technical Field

[0001] The present application relates to the technical field of hydrogen chloride synthesis, and in particular to a production system of food-grade hydrochloric acid. Background Art

[0002] Hydrochloric acid is a colorless liquid with a pungent odor. It turns slightly yellow when there are impurities. It is highly corrosive. Concentrated hydrochloric acid will smoke in the air and produce white clouds when it comes into contact with ammonia vapor. Hydrochloric acid is an extremely strong inorganic acid that is corrosive to skin and fibers. It can react chemically with many metals to produce metal chlorides and release hydrogen. It reacts with metal oxides and alkalis to produce salts and water.

[0003] Hydrochloric acid includes industrial grade hydrochloric acid and food grade hydrochloric acid. Among them, food grade hydrochloric acid is mainly used in food processing, medicine and other industries. The most common use is as an acidifier, which is used in pickled food and making condiments. When making chemical soy sauce, the steamed bean cake and other raw materials can be soaked in a solution containing a certain amount of hydrochloric acid and maintained at a certain temperature. Hydrochloric acid has a catalytic effect and can promote the hydrolysis of complex proteins. After a certain period of time, amino acids with umami flavor are generated, and then neutralized with caustic soda (or soda ash) to obtain amino acid sodium. Food grade hydrochloric acid is also used in some peeling processes and cleaning of equipment on food manufacturing production lines.

[0004] The hydrogen chloride synthesis furnace is used to introduce hydrogen and chlorine into the reactor for synthesis reaction to produce hydrogen chloride gas. Generally, the produced hydrogen and chlorine with higher purity are directly input into the synthesis furnace for ignition. This will result in a large amount of hydrogen and chlorine being required in the production process of food-grade hydrochloric acid. In addition, hydrogen is generally in excess compared to chlorine, resulting in a greater demand for hydrogen. In long-term operation, hydrogen consumption is large, which in turn leads to higher costs in the production of food-grade hydrochloric acid. Utility Model Content

[0005] The present application provides a food-grade hydrochloric acid production system to solve the above-mentioned problems mentioned in the background technology.

[0006] The present application provides a food-grade hydrochloric acid production system, comprising: a vinyl chloride production device, a pressure swing adsorption device, an electrolysis device, a scrubbing tower, a hydrogen buffer tank, a chlorine buffer tank, a liquid chlorine compression device, a hydrogen chloride synthesis furnace and a hydrogen chloride falling film absorber.

[0007] The outlet of the vinyl chloride production device is connected to the pressure swing adsorption device, the hydrogen outlet of the pressure swing adsorption device is connected to the hydrogen buffer tank, the hydrogen outlet of the electrolysis device is connected to the gas inlet of the washing tower, and the outlet of the washing tower is also connected to the hydrogen buffer tank.

[0008] The tail gas outlet of the liquid chlorine compression device is connected to the chlorine buffer tank, the outlets of the hydrogen buffer tank and the chlorine buffer tank are both connected to the air inlet of the hydrogen chloride synthesis furnace, and the gas outlet of the hydrogen chloride synthesis furnace is connected to the hydrogen chloride falling film absorber.

[0009] Optionally, the hydrogen chloride synthesis furnace includes a graphite cylinder, a steel cylinder, a combustion lamp holder and a cooling unit, the steel cylinder is arranged on the periphery of the graphite cylinder, and the combustion lamp holder is located at the bottom of the graphite cylinder.

[0010] The cooling unit comprises a jacket, a cavity formed between the steel cylinder and the graphite cylinder is the jacket, a cooling water inlet is provided at the bottom of the steel cylinder, and a cooling water outlet is provided at the top of the steel cylinder.

[0011] Optionally, the cooling unit further comprises a graphite heat exchange plate, which is located at the upper part of the graphite cylinder, and the graphite heat exchange plate comprises a horizontal cooling water flow channel and a hydrogen chloride through hole penetrating from top to bottom.

[0012] The cooling water circulation channel includes a cooling water through-pipe horizontally opened in the graphite heat exchange plate, the cooling water through-pipe is connected with a plurality of annular cooling water branch pipes, the outlet ends of the plurality of annular cooling water branch pipes are all connected with a cooling water outlet pipe, a plurality of hydrogen chloride through-holes are vertically penetrated in the graphite heat exchange plate, and the plurality of hydrogen chloride through-holes are staggered with the cooling water through-pipe, the annular cooling water branch pipe and the cooling water outlet pipe.

[0013] Optionally, a first regulating valve is provided at the cooling water inlet, and a second regulating valve is provided on the cooling water through pipe.

[0014] Optionally, the combustion lamp holder includes three layers of coaxially sleeved gas pipes with different diameters, which are respectively a first hydrogen gas pipe, a chlorine gas pipe and a second hydrogen gas pipe from the inside to the outside.

[0015] Optionally, the outlet end of the first hydrogen gas pipeline is connected to an arc-shaped cover body, on which a plurality of air holes are evenly formed, and the outlet end of the chlorine gas pipeline is connected to a plurality of air guide plates, which are spirally gathered along the outlet direction of the chlorine gas movement.

[0016] Optionally, the diameter of the outlet end of the second hydrogen gas pipeline is smaller than the diameter of the pipe body of the second hydrogen gas pipeline.

[0017] Optionally, the liquid phase outlet of the hydrogen chloride falling film absorber is connected to a food-grade hydrochloric acid storage tank, the gas phase outlet of the hydrogen chloride falling film absorber is connected to an alkali solution absorption tank, and the alkali solution absorption tank is connected to an alkali solution circulation tank via an alkali solution pump.

[0018] The food-grade hydrochloric acid production system provided in this application realizes the efficient production of food-grade hydrochloric acid and has the following beneficial effects compared with the prior art:

[0019] (1) The hydrogen in the vinyl chloride production process is purified by a pressure swing adsorption device to obtain a first hydrogen, and the hydrogen produced in the electrolysis process is washed by a washing tower to obtain a second hydrogen, and the first hydrogen and the second hydrogen are used together to synthesize hydrogen chloride. At the same time, the chlorine tail gas in the liquid chlorine compression device in the chlorine hydraulic process is burned with the first hydrogen and the second hydrogen in a hydrogen chloride synthesis furnace to generate crude hydrogen chloride, which is then passed through a hydrogen chloride falling film absorber so that the desalted water absorbs the hydrogen chloride to obtain food-grade hydrochloric acid. This not only helps to recycle hydrogen, but also avoids hydrogen waste and reduces production costs, which has good economic benefits for enterprises.

[0020] (2) The temperature of hydrogen chloride generated by combustion is reduced by arranging a jacket and a graphite heat exchange plate. The graphite heat exchange plate includes a horizontal cooling water flow channel and a hydrogen chloride through hole that runs through the graphite heat exchange plate from bottom to top, so that the hydrogen chloride generated by combustion passes through the hydrogen chloride through hole from bottom to top to reach the top of the graphite heat exchange plate. In the process of hydrogen chloride passing through the hydrogen chloride through hole, condensed water flows horizontally in the graphite heat exchange plate through the cooling water through pipe, the annular cooling water branch pipe and the cooling water outlet pipe. At this time, the condensed water and hydrogen chloride are further exchanged with heat, so that the temperature of hydrogen chloride is reduced again, which is convenient for the subsequent absorption of hydrogen chloride gas, and then it is convenient to produce food-grade hydrochloric acid.

[0021] (3) The outlet end of the first hydrogen gas pipeline is provided with an arc-shaped cover body, and a plurality of air holes are evenly opened on the arc-shaped cover body. The outlet end of the chlorine gas pipeline is connected with a plurality of air guide plates, and the plurality of air guide plates are arranged in a spiral gathering manner along the direction of movement of the chlorine gas. In this way, the chlorine gas is output while moving upward in a spiral motion. At the same time, when the chlorine gas is moving in a spiral motion, a negative pressure is formed at the outlet end of the chlorine gas pipeline, which generates an attraction force on the hydrogen gas at the outlet end of the first hydrogen gas pipeline and the hydrogen gas at the outlet end of the second hydrogen gas pipeline, so that the hydrogen gas at the two outlet ends and the chlorine gas rise in a spiral together, thus further improving the mixing degree of hydrogen and chlorine, facilitating the combustion of hydrogen and chlorine, generating hydrogen chloride to the maximum extent, improving the utilization rate of the raw gas hydrogen and chlorine, and improving the generation efficiency of hydrogen chloride, thereby improving the production efficiency of food-grade hydrochloric acid. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of the structure of a food-grade hydrochloric acid production system provided in one embodiment of the present application;

[0024] Figure 2 A schematic diagram of the structure of a hydrogen chloride synthesis furnace provided in one embodiment of the present application;

[0025] Figure 3 A schematic diagram of the structure of a graphite heat exchange plate provided in one embodiment of the present application;

[0026] Figure 4 A schematic diagram of the structure of a graphite heat exchange plate provided in another embodiment of the present application;

[0027] Figure 5 A schematic diagram of the structure of a burning lamp holder provided in one embodiment of the present application;

[0028] Figure 6 A schematic diagram of the structure of a food-grade hydrochloric acid production system provided in another embodiment of the present application;

[0029] Description of reference numerals:

[0030] 1: Vinyl chloride production unit, 2: Electrolysis unit, 3: Hydrogen buffer tank, 4: Chlorine buffer tank, 5: Hydrogen chloride synthesis furnace, 6: Hydrogen chloride falling film absorber, 7: Food grade hydrochloric acid storage tank, 8: Alkali liquid absorption tank, 110: Pressure swing adsorption unit, 210: Scrubber, 410: Liquid chlorine compression unit, 510: Graphite cylinder, 520: Steel cylinder, 530: Jacket, 531: Water inlet, 532: Water outlet, 533: First regulating valve , 540: graphite heat exchange plate, 541: condensate water pipe, 542: condensate water branch pipe, 543: condensate water outlet pipe, 544: second regulating valve, 550: hydrogen chloride through hole, 560: combustion lamp holder, 561: first hydrogen gas pipeline, 562: chlorine gas pipeline, 563: second hydrogen gas pipeline, 810: alkali liquid pump, 820: alkali liquid circulation tank, 5601: arc cover, 5602: air hole, 5603: air guide plate. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0032] like Figure 1 As shown, the present application provides a food-grade hydrochloric acid production system, including: a vinyl chloride production device 1, a pressure swing adsorption device 110, an electrolysis device 2, a washing tower 210, a hydrogen buffer tank 3, a chlorine buffer tank 4, a liquid chlorine compression device 410, a hydrogen chloride synthesis furnace 5 and a hydrogen chloride falling film absorber 6.

[0033] The outlet of the vinyl chloride production device 1 is connected to the pressure swing adsorption device 110, the hydrogen outlet of the pressure swing adsorption device 110 is connected to the hydrogen buffer tank 3, the hydrogen outlet of the electrolysis device 2 is connected to the gas inlet of the washing tower 210, and the outlet of the washing tower 210 is also connected to the hydrogen buffer tank 3.

[0034] The tail gas outlet of the liquid chlorine compression device 410 is connected to the chlorine buffer tank 4, the outlets of the hydrogen buffer tank 3 and the chlorine buffer tank 4 are both connected to the air inlet of the hydrogen chloride synthesis furnace 5, and the gas outlet of the hydrogen chloride synthesis furnace 5 is connected to the hydrogen chloride falling film absorber 6.

[0035] Specifically, the production of food-grade hydrochloric acid in the present application first generates hydrogen chloride gas by igniting hydrogen and chlorine in a hydrogen chloride synthesis furnace 5, and then absorbs the obtained hydrogen chloride gas by desalting water to obtain food-grade hydrochloric acid with a hydrochloric acid concentration of ≥32%. The hydrogen used in the present application comes from two processes. First, there is a vinyl chloride production line in the factory site. Vinyl chloride production is generated by the reaction of hydrogen chloride and acetylene. Hydrogen chloride comes from an industrial hydrogen chloride synthesis furnace. In the industrial hydrogen chloride synthesis furnace, excess hydrogen and chlorine are ignited to generate hydrogen chloride gas. Due to the excess hydrogen, the hydrogen chloride entering the vinyl chloride production process contains a certain amount of hydrogen. In the vinyl chloride production process, hydrogen chloride containing hydrogen reacts with acetylene to generate hydrogen in addition to the target product vinyl chloride. If these hydrogens are vented, a large amount of hydrogen will be wasted. Therefore, the hydrogen in the vinyl chloride production process is purified and used in the production of food-grade hydrochloric acid, which not only helps to recycle hydrogen, but also avoids hydrogen waste and reduces production costs, which has good economic benefits for enterprises.

[0036] Another source of hydrogen in the present application is hydrogen produced in the electrolysis process, and the hydrogen from the electrolysis process is washed and used together with hydrogen from the vinyl chloride production process to synthesize hydrogen chloride.

[0037] The chlorine in the present application comes from the tail gas of chlorine liquefaction, which not only provides raw materials for the production of food-grade hydrochloric acid, but also avoids the treatment of chlorine liquefaction tail gas, which not only improves the utilization rate of liquefied tail gas, but also further reduces production costs.

[0038] When producing,

[0039] (1) The vinyl chloride mixed gas containing hydrogen obtained in the vinyl chloride production device 1 is transported to the pressure swing adsorption device 110, and the vinyl chloride is subjected to pressure swing adsorption to separate hydrogen from the vinyl chloride to obtain the first hydrogen. The temperature of the pressure swing adsorption is 20-40°C, and the pressure of the raw gas (the vinyl chloride mixed gas containing hydrogen) in each process of the pressure swing adsorption is 0.47-0.55MPa, the pressure of the analysis gas (recovered vinyl chloride) is ≤55KPa, the pressure of the purified gas (recovered hydrogen delivery) is 0.45-0.55MPa, and the pressure of the product hydrogen (first hydrogen) is 0.45-0.5MPa. The pressure swing adsorption process is a relatively mature technology in the industry and will not be described in detail here.

[0040] (2) The hydrogen generated by the electrolysis device 2 is washed through the washing tower 210. During washing, water is sprayed from top to bottom through the top of the washing tower 210, and the electrolyzed hydrogen is introduced from the lower part of the washing tower 210. The electrolyzed hydrogen moves from bottom to top, and the sprayed water falls from top to bottom, so that the electrolyzed hydrogen and the sprayed water are in countercurrent contact, and the alkali entrained in the electrolyzed hydrogen is dissolved in the water, completing the purification and washing of the electrolyzed hydrogen, and obtaining the second hydrogen at the top of the washing tower 210, and the first hydrogen and the second hydrogen are both transported to the hydrogen buffer tank 3 for temporary storage, so as to facilitate the subsequent synthesis of hydrogen chloride. Due to the need to be applied to food production, in the production process of food-grade hydrochloric acid, the electrolyzed hydrogen and the hydrogen in the production of vinyl chloride are purified to ensure the purity of the raw hydrogen, so as to reduce impurities in the food-grade hydrochloric acid product and avoid excessive impurities in the food-grade hydrochloric acid.

[0041] The purity of hydrogen produced by the pressure swing adsorption device 110 and the washing tower 210 is ≥ 99.5%, thereby reducing impurities in the target product, food-grade hydrochloric acid. The temperature of the hydrogen at the outlet of the washing tower 210 is 20-45° C., which facilitates safe and stable storage of hydrogen in the hydrogen buffer tank 3.

[0042] (3) The chlorine tail gas from the liquid chlorine compression device 410 during the chlorine hydraulic process is transported to the chlorine buffer tank 4 for temporary storage to facilitate the subsequent synthesis of hydrogen chloride. The purity of the chlorine from the liquid chlorine compression device 410 is ≥80.0%.

[0043] (4) The chlorine in the chlorine buffer tank 4 is transported to the hydrogen chloride synthesis furnace 5 through the hydrogen pipeline from the bottom of the hydrogen chloride synthesis furnace 5, and at the same time, the hydrogen in the hydrogen buffer tank 3 is transported to the hydrogen chloride synthesis furnace through the hydrogen pipeline from the bottom of the hydrogen chloride synthesis furnace 5, so that the hydrogen and chlorine are burned to generate raw hydrogen chloride gas.

[0044] (5) The crude hydrogen chloride gas in the hydrogen chloride synthesis furnace 5 is transported to the hydrogen chloride falling film absorber 6. The desalted water enters the hydrogen chloride falling film absorber 6 from top to bottom and flows along the tube bundle in a film-like manner. The hydrogen chloride gas flows in the reverse direction to achieve mass transfer and heat transfer. The hydrogen chloride gas is absorbed by the desalted water to obtain food-grade hydrochloric acid. The temperature during the hydrogen chloride falling film absorption process is ≤55°C.

[0045] Wherein, a plurality of hydrogen chloride falling film absorbers 6 are arranged in series according to actual on-site working conditions.

[0046] The present application realizes the efficient production of food-grade hydrochloric acid through the above scheme. The hydrogen in the vinyl chloride production process is purified by a pressure swing adsorption device to obtain a first hydrogen, and the hydrogen produced in the electrolysis process is washed by a washing tower to obtain a second hydrogen, and the first hydrogen and the second hydrogen are used together for the synthesis of hydrogen chloride. At the same time, the chlorine tail gas in the liquid chlorine compression device in the chlorine hydraulic process is burned with the first hydrogen and the second hydrogen in a hydrogen chloride synthesis furnace to generate crude hydrogen chloride, and then passes through a hydrogen chloride falling film absorber 6, so that the desalted water absorbs the hydrogen chloride to obtain food-grade hydrochloric acid. This not only helps to recycle hydrogen, but also avoids hydrogen waste, while reducing production costs, and has good economic benefits for enterprises.

[0047] like Figure 2 As shown, optionally, the hydrogen chloride synthesis furnace 5 includes a graphite cylinder 510 , a steel cylinder 520 , a combustion lamp holder 560 and a cooling unit, the steel cylinder 520 is arranged on the periphery of the graphite cylinder 510 , and the combustion lamp holder 560 is located at the bottom of the graphite cylinder 510 .

[0048] The cooling unit includes a jacket 530 . The cavity formed between the steel cylinder 520 and the graphite cylinder 510 is the jacket 530 . A cooling water inlet 531 is provided at the bottom of the steel cylinder 520 , and a cooling water outlet 532 is provided at the top of the steel cylinder 520 .

[0049] Specifically, the interior of the hydrogen chloride synthesis furnace 5 is a graphite cylinder 510. The use of graphite makes the synthesis furnace have good heat resistance, thermal conductivity and chemical stability, is not easy to corrode, and improves the operation cycle and stability of the hydrogen chloride synthesis furnace 5. At the same time, the graphite cylinder 510 makes the generated hydrogen chloride free of Fe 3+ Pollution is eliminated, and the purity of food-grade hydrochloric acid is further improved. The combustion lamp holder 560 is used to ignite hydrogen and chlorine to generate hydrogen chloride. The combustion lamp holder 560 is located at the bottom of the graphite cylinder 510. The hydrogen chloride generated by the combustion moves from bottom to top in the graphite cylinder 510. At the same time, a large amount of heat is generated during the combustion. The cooling unit is used to perform heat exchange on the generated heat to cool the hydrogen chloride. The gas outlet at the top of the hydrogen chloride synthesis furnace 5 is connected to the hydrogen chloride falling film absorber 6. The desalted water in the hydrogen chloride falling film absorber 6 absorbs the hydrogen chloride to obtain food-grade hydrochloric acid.

[0050] Cooling water is introduced from the cooling water inlet 531, and the cooling water performs heat exchange with the hydrogen chloride in the graphite cylinder 510 in the jacket 530, so that the temperature of the hydrogen chloride is reduced, and the temperature of the cooling water is increased, and is output from the cooling water outlet 532. Furthermore, the increased temperature cooling water is input to the cooling unit for cooling, and then input back to the jacket 530 for heat exchange, so that the cooling water is recycled and water resources are avoided from being wasted.

[0051] like Figure 2 , Figure 3 and Figure 4 As shown, optionally, the cooling unit further includes a graphite heat exchange plate 540, which is located at the upper part of the graphite cylinder 510, and the graphite heat exchange plate 540 includes a horizontal cooling water flow channel and a hydrogen chloride through hole 550 that penetrates from top to bottom.

[0052] The cooling water circulation channel includes a cooling water through pipe 541 horizontally opened in the graphite heat exchange plate 540, and the cooling water through pipe 541 is connected to a plurality of annular cooling water branch pipes 542, and the outlet ends of the plurality of annular cooling water branch pipes 542 are all connected to a cooling water outlet pipe 543. A plurality of hydrogen chloride through holes 550 are penetrated from top to bottom in the graphite heat exchange plate 540, and the plurality of hydrogen chloride through holes 550 and the cooling water through pipe 541, the annular cooling water branch pipe 542 and the cooling water outlet pipe 543 are all staggered.

[0053] Specifically, the hydrogen chloride generated by combustion moves from bottom to top in the graphite cylinder 510, and the temperature gradually decreases during the movement. The graphite heat exchange plate 540 is arranged at the upper part of the graphite cylinder 510 to further cool the hydrogen chloride. The cooling water circulation channel includes a cooling water pipe 541 horizontally opened in the graphite heat exchange plate 540, and the cooling water pipe 541 is connected to the external cooling water pipe. The cooling water enters the graphite heat exchange plate 540 through the cooling water pipe 541, flows to multiple annular cooling water branches 542, and finally is concentrated and discharged through the cooling water outlet pipe 543. The cooling water flows horizontally in the graphite heat exchange plate 540. At the same time, the graphite heat exchange plate 540 is provided with a hydrogen chloride through hole 550 that penetrates from top to bottom, so that the hydrogen chloride generated by combustion passes through the hydrogen chloride through hole 550 from bottom to top to reach the top of the graphite heat exchange plate 540. In the process of hydrogen chloride passing through the hydrogen chloride through hole 550, condensed water flows horizontally in the graphite heat exchange plate 540 through the cooling water through pipe 541, the annular cooling water branch pipe 542 and the cooling water outlet pipe 543. At this time, the condensed water further exchanges heat with the hydrogen chloride, so that the temperature of the hydrogen chloride is reduced again, and finally output from the top of the hydrogen chloride synthesis furnace 5. Among them, the temperature of the hydrogen chloride gas output from the top of the hydrogen chloride synthesis furnace 5 is ≤50°C, which is convenient for the subsequent absorption of the hydrogen chloride gas, and then convenient for the production of food-grade hydrochloric acid.

[0054] The plurality of hydrogen chloride through holes 550 and the cooling water through pipe 541, the annular cooling water branch pipe 542 and the cooling water outlet pipe 543 are all staggered to avoid direct contact between hydrogen chloride gas and condensed water, thereby facilitating cooling of hydrogen chloride.

[0055] In the present application, a graphite heat exchange plate 540 is used, and a cooling water circulation channel is opened in the horizontal direction of the graphite heat exchange plate 540, and a hydrogen chloride through hole 550 is opened on the graphite heat exchange plate 540 to penetrate from top to bottom. First, the graphite material is used to prevent the rising hydrogen chloride gas from corroding the graphite heat exchange plate 540, and graphite has good thermal conductivity, which can accelerate the heat exchange between hydrogen chloride and condensed water in the graphite heat exchange plate 540, and help the hydrogen chloride gas to further quickly cool down. In addition, the hydrogen chloride gas moves from bottom to top, the condensed water moves from left to right (or from right to left), and the heat transfer medium is the graphite heat exchange plate 540, which improves the heat exchange efficiency.

[0056] like Figure 3 and Figure 4 As shown, optionally, the cooling water inlet 531 is provided with a first regulating valve 533 , and the cooling water through pipe 541 is provided with a second regulating valve 544 .

[0057] Specifically, adjusting the opening of the first regulating valve 533 can adjust the amount of cooling water entering the jacket 530, and adjusting the opening of the second regulating valve 544 can adjust the amount of cooling water entering the graphite heat exchange plate 540, thereby facilitating the adjustment of the temperature of the hydrogen chloride.

[0058] like Figure 5 As shown, optionally, the burning lamp holder 560 includes three layers of coaxially sleeved gas pipes with different diameters, which are respectively a first hydrogen gas pipe 561, a chlorine gas pipe 562 and a second hydrogen gas pipe 563 from the inside to the outside.

[0059] Specifically, the burning lamp holder 560 is coaxially sleeved with a first hydrogen gas pipe 561, a chlorine gas pipe 562 and a second hydrogen gas pipe 563. This arrangement helps to mix hydrogen and chlorine evenly and allows hydrogen and chlorine to burn fully, thereby reducing waste of gas raw materials.

[0060] like Figure 5 As shown, optionally, the outlet end of the first hydrogen gas pipeline 561 is connected to an arc-shaped cover body 5601, and a plurality of air holes 5602 are evenly opened on the arc-shaped cover body 5601. The outlet end of the chlorine gas pipeline 562 is connected to a plurality of air guide plates 5603, and the plurality of air guide plates 5603 are spirally gathered along the outlet direction of the chlorine gas movement.

[0061] Specifically, the outlet end of the first hydrogen gas delivery pipe 561 is connected to an arc-shaped cover body 5601, and an air hole 5602 is opened on the arc-shaped cover body 5601. When the first hydrogen is output, it is output through the air hole 5602 on the arc-shaped cover body 5601, so that the hydrogen output from the first hydrogen gas delivery pipe 561 is more uniform. At the same time, a plurality of air guide plates 5603 at the outlet end of the chlorine gas delivery pipe 562 are spirally gathered along the direction of movement of the chlorine gas, so that when the chlorine gas is output, it moves upward while moving in a spiral motion. At the same time, the chlorine gas spirally moves. At the same time, negative pressure is formed at the outlet end of the chlorine gas pipeline 562, which generates attraction for the hydrogen at the outlet end of the first hydrogen gas pipeline 561 and the hydrogen at the outlet end of the second hydrogen gas pipeline 563, so that the hydrogen and chlorine at the two outlet ends spiral upward together, thereby further improving the mixing degree of hydrogen and chlorine, facilitating the combustion of hydrogen and chlorine, generating hydrogen chloride to the greatest extent, improving the utilization rate of the raw gas hydrogen and chlorine, and at the same time improving the generation efficiency of hydrogen chloride, thereby improving the production efficiency of food-grade hydrochloric acid.

[0062] Optionally, the diameter of the outlet end of the second hydrogen gas delivery pipe 563 is smaller than the diameter of the pipe body of the second hydrogen gas delivery pipe 563 .

[0063] Specifically, this helps to improve the mixing degree of the hydrogen and chlorine output by the second hydrogen gas transmission pipe 563, and helps to fully burn the hydrogen and chlorine during combustion.

[0064] like Figure 6 As shown, optionally, the liquid phase outlet of the hydrogen chloride falling film absorber 6 is connected to a food-grade hydrochloric acid storage tank 7, the gas phase outlet of the hydrogen chloride falling film absorber 6 is connected to an alkali solution absorption tank 8, and the alkali solution absorption tank 8 is connected to an alkali solution circulation tank 820 via an alkali solution pump 810.

[0065] Specifically, the desalted water in the hydrogen chloride falling film absorber 6 absorbs hydrogen chloride to form food-grade hydrochloric acid, which is then transported to the food-grade hydrochloric acid storage tank 7 for storage. There is still a small amount of non-condensable gas in the hydrogen chloride falling film absorber 6, including a small amount of acidic gas and a trace amount of hydrogen. These gases are transported to the gas phase outlet alkali liquid absorption tank 8, where the acidic gas is absorbed by the alkali liquid, and the remaining gas after absorption is discharged through the top of the alkali liquid absorption tank 8. The alkali liquid in the alkali liquid circulation tank 820 is transported to the alkali liquid absorption tank 8 for utilization by the alkali liquid pump 810, wherein the concentration of the alkali liquid is not limited here and is determined by the actual working conditions. And when the alkali liquid concentration in the alkali liquid circulation tank 820 is ≤3%, the alkali liquid in the alkali liquid circulation tank 820 is transported to the wastewater treatment process for treatment, and new alkali liquid is input into the alkali liquid circulation tank 820.

[0066] The technical solution of the present application is described in detail below with reference to specific embodiments.

[0067] The production system of food-grade hydrochloric acid in this embodiment has the following operation flow during specific operation:

[0068] (1) The vinyl chloride mixed gas containing hydrogen obtained in the vinyl chloride production device 1 is transported to the pressure swing adsorption device 110, and the vinyl chloride is subjected to pressure swing adsorption to separate hydrogen from the vinyl chloride to obtain the first hydrogen. The temperature of the pressure swing adsorption is 20-40°C.

[0069] (2) The hydrogen generated by the electrolysis device 2 is washed by a washing tower 210. During washing, water is sprayed from top to bottom through the top of the washing tower 210, and the electrolyzed hydrogen is introduced from the bottom of the washing tower 210. The electrolyzed hydrogen moves from bottom to top, and the sprayed water falls from top to bottom, so that the electrolyzed hydrogen and the sprayed water are in countercurrent contact, and the alkali entrained in the electrolyzed hydrogen is dissolved in the water, completing the purification and washing of the electrolyzed hydrogen. A second hydrogen is obtained at the top of the washing tower 210, and the first hydrogen and the second hydrogen are both transported to the hydrogen buffer tank 3 for temporary storage, so as to facilitate the subsequent synthesis of hydrogen chloride.

[0070] The purity of hydrogen produced by the pressure swing adsorption device 110 and the washing tower 210 is ≥ 99.5%, thereby reducing impurities in the target product, food-grade hydrochloric acid. The temperature of the hydrogen at the outlet of the washing tower 210 is 20-45° C., which facilitates safe and stable storage of hydrogen in the hydrogen buffer tank 3.

[0071] (3) The chlorine tail gas from the liquid chlorine compression device 410 during the chlorine hydraulic process is transported to the chlorine buffer tank 4 for temporary storage to facilitate the subsequent synthesis of hydrogen chloride. The purity of the chlorine from the liquid chlorine compression device 410 is ≥80.0%.

[0072] (4) The chlorine in the chlorine buffer tank 4 is transported to the hydrogen chloride synthesis furnace 5 through the hydrogen pipeline from the bottom of the hydrogen chloride synthesis furnace 5, and the hydrogen in the hydrogen buffer tank 3 is transported to the hydrogen chloride synthesis furnace 5 through the hydrogen pipeline from the bottom of the hydrogen chloride synthesis furnace 5, so that the hydrogen and the chlorine are burned to generate raw hydrogen chloride gas. During the combustion process, cooling water is introduced from the cooling water inlet 531, and the cooling water performs heat exchange with the hydrogen chloride in the graphite cylinder 510 in the jacket 530, so that the temperature of the hydrogen chloride is reduced, the temperature of the cooling water is increased, and the cooling water is output from the cooling water outlet 532.

[0073] The cooling water enters the graphite heat exchange plate 540 through the cooling water pipe 541, flows to a plurality of annular cooling water branches 542, and finally is discharged through the cooling water outlet pipe 543. The cooling water flows horizontally in the graphite heat exchange plate 540. At the same time, the graphite heat exchange plate 540 is provided with a hydrogen chloride through hole 550 which runs through from top to bottom, so that the hydrogen chloride generated by combustion passes through the hydrogen chloride through hole 550 from bottom to top to reach the top of the graphite heat exchange plate 540. In the process of hydrogen chloride passing through the hydrogen chloride through hole 550, the condensed water flows horizontally in the graphite heat exchange plate 540 through the cooling water pipe 541, the annular cooling water branch pipe 542 and the cooling water outlet pipe 543. At this time, the condensed water further exchanges heat with the hydrogen chloride and is finally discharged from the top of the hydrogen chloride synthesis furnace 5. By adjusting the opening of the first regulating valve 533, the amount of cooling water entering the jacket 530 can be adjusted. By adjusting the opening of the second regulating valve 544, the amount of cooling water entering the graphite heat exchange plate 540 can be adjusted, so that the temperature of the hydrogen chloride gas output from the top of the hydrogen chloride synthesis furnace 5 is ≤50°C.

[0074] (5) The crude hydrogen chloride gas in the hydrogen chloride synthesis furnace 5 is transported to the hydrogen chloride falling film absorber 6. The desalted water enters the hydrogen chloride falling film absorber 6 from top to bottom and flows along the tube bundle in a film-like manner. The hydrogen chloride gas flows in the reverse direction to achieve mass transfer and heat transfer. The hydrogen chloride gas is absorbed by the desalted water. During the hydrogen chloride falling film absorption process, the temperature is ≤55°C, and the concentration of the obtained hydrochloric acid is regularly detected. When the concentration of the hydrochloric acid (total acidity) is ≥32%, food-grade hydrochloric acid is obtained and transported to the food-grade hydrochloric acid storage tank 7 for storage. A small amount of non-condensable gas in the hydrogen chloride falling film absorber 6 is transported to the gas phase outlet alkali liquid absorption tank 8, and the acidic gas therein is absorbed by the alkali liquid. The remaining gas after absorption is discharged through the top of the alkali liquid absorption tank 8. The alkali liquid in the alkali liquid circulation tank 820 is transported to the alkali liquid absorption tank 8 for utilization through the alkali liquid pump 810. When the alkali liquid concentration in the alkali liquid circulation tank 820 is ≤3%, the alkali liquid in the alkali liquid circulation tank 820 is transported to the wastewater treatment process for treatment, and new alkali liquid is input into the alkali liquid circulation tank 820.

[0075] The test results of various indicators of the obtained food-grade hydrochloric acid are shown in Table 1.

[0076] Table 1

[0077] project unit index Product analysis results Color / Colorless or light yellow Colorless or light yellow state / Transparent liquid Transparent liquid Total acidity (as HCl) W / ％ ≥31.0 32 Iron (as Fe) W / ％ ≤0.0005 0.00005 <![CDATA[Sulfate (calculated as SO 4 calculated)]]> W / ％ ≤0.007 0.005 Free chlorine (as Cl) W / ％ ≤0.003 0.002 <![CDATA[Reduced substance (calculated as SO 3 count)]]> W / ％ ≤0.007 / Non-volatile matter W / ％ ≤0.05 ＜0.01 Arsenic (As) mg / kg ≤1.0 ＜1.0 Heavy metals (measured in Pb) mg / kg ≤5 ＜1.0

[0078] The food-grade hydrochloric acid produced by the food-grade hydrochloric acid production system and method provided in the present application is tested based on the national standard "Food Additive Hydrochloric Acid GB 1886.9-2016". All indicators of the food-grade hydrochloric acid produced in this embodiment meet the national standard. The present application uses recycled hydrogen and liquid chlorine tail gas to produce food-grade hydrochloric acid, which not only realizes the efficient production of food-grade hydrochloric acid, but also enables the by-product hydrogen and liquid chlorine tail gas in the production of vinyl chloride to be recycled and utilized, thereby avoiding waste of resources and greatly reducing the production cost of food-grade hydrochloric acid.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A production system for food-grade hydrochloric acid, characterized in that: include: A vinyl chloride production device (1), a pressure swing adsorption device (110), an electrolysis device (2), a washing tower (210), a hydrogen buffer tank (3), a chlorine buffer tank (4), a liquid chlorine compression device (410), a hydrogen chloride synthesis furnace (5) and a hydrogen chloride falling film absorber (6); The outlet of the vinyl chloride production device (1) is connected to the pressure swing adsorption device (110), the hydrogen outlet of the pressure swing adsorption device (110) is connected to the hydrogen buffer tank (3), the hydrogen outlet of the electrolysis device (2) is connected to the gas inlet of the washing tower (210), and the outlet of the washing tower (210) is also connected to the hydrogen buffer tank (3); The tail gas outlet of the liquid chlorine compression device (410) is connected to the chlorine buffer tank (4), the outlets of the hydrogen buffer tank (3) and the chlorine buffer tank (4) are both connected to the air inlet of the hydrogen chloride synthesis furnace (5), the gas outlet of the hydrogen chloride synthesis furnace (5) is connected to the hydrogen chloride falling film absorber (6), and the liquid phase outlet of the hydrogen chloride falling film absorber (6) is connected to a food-grade hydrochloric acid storage tank (7).

2. The production system of food-grade hydrochloric acid according to claim 1, characterized in that: The hydrogen chloride synthesis furnace (5) comprises a graphite cylinder (510), a steel cylinder (520), a combustion lamp holder (560) and a cooling unit, wherein the steel cylinder (520) is arranged on the outer periphery of the graphite cylinder (510), and the combustion lamp holder (560) is located at the bottom of the graphite cylinder (510); The cooling unit comprises a jacket (530), a cavity formed between the steel cylinder (520) and the graphite cylinder (510) being the jacket (530), a cooling water inlet (531) being provided at the bottom of the steel cylinder (520), and a cooling water outlet (532) being provided at the top of the steel cylinder (520).

3. The production system of food-grade hydrochloric acid according to claim 2, characterized in that: The cooling unit further comprises a graphite heat exchange plate (540), the graphite heat exchange plate (540) being located at the upper portion of the graphite cylinder (510), the graphite heat exchange plate (540) comprising a horizontal cooling water flow channel and a hydrogen chloride through hole (550) penetrating vertically; The cooling water circulation channel comprises a cooling water pipe (541) horizontally opened in the graphite heat exchange plate (540); the cooling water pipe (541) is connected to a plurality of annular cooling water branch pipes (542); outlet ends of the plurality of annular cooling water branch pipes (542) are all connected to a cooling water outlet pipe (543); a plurality of hydrogen chloride through holes (550) are vertically penetrated in the graphite heat exchange plate (540); the plurality of hydrogen chloride through holes (550) are staggered with the cooling water pipe (541), the annular cooling water branch pipe (542) and the cooling water outlet pipe (543).

4. The production system of food-grade hydrochloric acid according to claim 3, characterized in that: The cooling water inlet (531) is provided with a first regulating valve (533), and the cooling water through pipe (541) is provided with a second regulating valve (544).

5. The production system of food-grade hydrochloric acid according to claim 4, characterized in that: The combustion lamp holder (560) comprises three layers of coaxially sleeved gas pipes with different diameters, which are respectively a first hydrogen gas pipe (561), a chlorine gas pipe (562) and a second hydrogen gas pipe (563) from the inside to the outside.

6. The production system of food-grade hydrochloric acid according to claim 5, characterized in that: The outlet end of the first hydrogen gas transmission pipe (561) is connected to an arc-shaped cover body (5601), and a plurality of air holes (5602) are evenly arranged on the arc-shaped cover body (5601). The outlet end of the chlorine gas transmission pipe (562) is connected to a plurality of air guide plates (5603), and the plurality of air guide plates (5603) are spirally gathered along the outlet direction of the chlorine gas movement.

7. The production system of food-grade hydrochloric acid according to claim 6, characterized in that: The diameter of the outlet end of the second hydrogen gas transmission pipe (563) is smaller than the diameter of the pipe body of the second hydrogen gas transmission pipe (563).

8. The production system of food-grade hydrochloric acid according to any one of claims 1 to 7, characterized in that: The gas phase outlet of the hydrogen chloride falling film absorber (6) is connected to an alkali solution absorption tank (8), and the alkali solution absorption tank (8) is connected to an alkali solution circulation tank (820) via an alkali solution pump (810).

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