System for purifying high-purity hydrogen from chlor-alkali byproduct hydrogen

Abstract

The utility model discloses a system for purifying high-purity hydrogen from chlor-alkali by-product hydrogen, which comprises a purification process, an electrolytic bath of the purification process is used for electrolyzing to generate by-product hydrogen, the by-product hydrogen is conveyed to a gas-liquid separator through a pipeline, and the gas-liquid separator is used for removing liquid water and conveying the by-product hydrogen to a washing tower through a pipeline; the washing tower is used for removing alkali mist and conveying byproduct hydrogen to the condenser through a pipeline; the condenser conveys the condensed byproduct hydrogen to the molecular sieve adsorption tower through a pipeline; the molecular sieve adsorption tower conveys purified byproduct hydrogen to the PSA purification system through a first compressor; according to the device disclosed by the utility model, the byproduct H2 of the electrolytic bath is conveyed to the washing tower for washing after liquid water is removed through the gas-liquid separator, alkali mist carried by the H2 is removed through the washing tower, water in a gas phase is condensed and discharged through the condenser after washing is completed, then the water is purified through the molecular sieve adsorption tower, and then the purified water is conveyed to the purification system through the first compressor, so that the yield of the H2 is increased.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical industry, in particular to a system for purifying high-purity hydrogen from chlorine-alkali byproduct hydrogen. Background Art

[0002] High-purity hydrogen is an important type of industrial gas and is widely used in many fields such as chemical industry, petrochemical industry, petroleum, energy, electronics, metallurgy, food, machinery, aerospace, nuclear industry, etc. At present, the hydrogen containing saturated water vapor coming out of the electrolyzer of chlor-alkali enterprises is used for the production of hydrochloric acid, vinyl chloride monomer and hydrogen peroxide after being treated in the chlorine-hydrogen section. Many chlor-alkali enterprises have a large amount of hydrogen venting, and some have to use it as boiler fuel, but compared with coal, its value is far lower than the added value of bottled hydrogen and hydrogen-consuming products.

[0003] The hydrogen produced by salt electrolysis in chlor-alkali enterprises is of high purity and simple impurity composition. Generally, the H2 content is greater than 90%, and even reaches over 98%. It mainly contains oxygen, water and chlorine. The carbon monoxide, carbon dioxide, methane content and high-purity hydrogen indicators are very low on the same order of magnitude. Recycling and preparing high-purity hydrogen has high commercial value.

[0004] At present, the main method for preparing high-purity hydrogen is pressure swing adsorption (PSA). Pressure swing adsorption uses the difference in adsorption characteristics of gas components on adsorbents and the principle that the adsorption amount changes with pressure to achieve gas separation through a periodic pressure change process. The technology has the advantages of low energy consumption, high product purity, relatively simple process flow, low pretreatment requirements, convenient and reliable operation, and a high degree of automation. It is widely used in the field of gas separation. The PSA method for hydrogen production can use various hydrogen-containing gas sources as raw materials. Depending on the raw hydrogen and the process route, high-purity hydrogen can be obtained without pretreatment in one step, or it can be refined in an adsorption tower after simple pretreatment. The main disadvantage of PSA technology is the low recovery rate and the inability to achieve good economic benefits.

[0005] Based on the above situation, the utility model proposes a system for purifying high-purity hydrogen from chlor-alkali by-product hydrogen, which can effectively solve the above problems. Utility Model Content

[0006] The purpose of the utility model is to provide a system for purifying high-purity hydrogen from chlorine-alkali byproduct hydrogen. The utility model provides a system for purifying high-purity hydrogen from chlorine-alkali byproduct hydrogen. The utility model electrolytic cell 1 produces H2 byproduct, which is transported to a washing tower for washing after removing the entrained liquid water through a gas-liquid separator. The washing tower removes the alkaline mist (OH) in H2. -), after washing is completed, the water in the gas phase is condensed and discharged through the condenser, and then the impurities such as H2O and NaCl in H2 are purified by the molecular sieve adsorption tower, and then transported to the purification system through the first compressor; the purification system adopts a two-stage adsorption process, and the tail gas that is not adsorbed by the first-stage PSA adsorption unit can continue to be adsorbed by the second-stage PSA adsorption unit, thereby increasing the yield of H2.

[0007] The utility model is realized by the following technical solutions:

[0008] A system for purifying high-purity hydrogen from chlorine-alkali byproduct hydrogen comprises a purification process and a purification and compression process; the purification process comprises an electrolytic cell, a gas-liquid separator, a washing tower, a condenser and a molecular sieve adsorption tower; the purification and compression process comprises a PSA purification system and a second compressor; the electrolytic cell is used for electrolysis to generate byproduct hydrogen, and the electrolytic cell transports the byproduct hydrogen to the gas-liquid separator through a pipeline, the gas-liquid separator is used for removing liquid water in the byproduct hydrogen, and transporting the byproduct hydrogen to the washing tower through a pipeline; the washing tower is used for removing alkali mist in the byproduct hydrogen, and transporting the byproduct hydrogen to the condenser through a pipeline; the condenser transports the condensed byproduct hydrogen to the molecular sieve adsorption tower through a pipeline; the molecular sieve adsorption tower is used for purifying the byproduct hydrogen, and transporting the purified byproduct hydrogen to the PSA purification system through a first compressor, and the PSA purification system is connected to the second compressor through a pipeline; the second compressor transports the pressurized hydrogen to a storage tank through a pipeline.

[0009] According to the above technical scheme, as a further preferred technical scheme of the above technical scheme, the PSA purification system includes a primary PSA adsorption unit and a secondary PSA adsorption unit connected to each other, the inlet end of the primary PSA adsorption unit is connected to the first compressor through a pipeline; the outlet ends of the primary PSA adsorption unit and the secondary PSA adsorption unit are connected to the second compressor through a pipeline.

[0010] According to the above technical solution, as a further preferred technical solution of the above technical solution, a tail gas output pipeline is arranged on the top of the secondary PSA adsorption unit.

[0011] According to the above technical solution, as a further preferred technical solution of the above technical solution, the outlet pressure of the first compressor is 1Mpa.

[0012] According to the above technical solution, as a further preferred technical solution of the above technical solution, the outlet pressure of the second compressor is 20Mpa or 50Mpa.

[0013] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0014] The utility model provides a system for purifying high-purity hydrogen from chlorine-alkali byproduct hydrogen. The byproduct H2 of the electrolytic cell 1 is transported to a washing tower for washing after removing the entrained liquid water through a gas-liquid separator. The washing tower removes the alkaline mist (OH) - ), after washing is completed, the water in the gas phase is condensed and discharged through the condenser, and then the impurities such as H2O and NaCl in H2 are purified by the molecular sieve adsorption tower, and then transported to the purification system through the first compressor; the purification system adopts a two-stage adsorption process, and the tail gas that is not adsorbed by the first-stage PSA adsorption unit can continue to be adsorbed by the second-stage PSA adsorption unit, thereby increasing the yield of H2. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the utility model. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand the technical solution of the utility model, the preferred implementation scheme of the utility model is described below in conjunction with specific embodiments. However, it should be understood that the drawings are only used for illustrative purposes and cannot be understood as a limitation on this patent. In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationship described in the drawings is only used for illustrative purposes and cannot be understood as a limitation on this patent.

[0017] A system for purifying high-purity hydrogen from byproduct hydrogen of chlor-alkali, comprising a purification process and a purification and compression process; the purification process comprises an electrolytic cell 1, a gas-liquid separator 2, a washing tower 3, a condenser 4 and a molecular sieve adsorption tower 5; the purification and compression process comprises a PSA purification system 7 and a second compressor 8; the electrolytic cell 1 is used for electrolysis to generate byproduct hydrogen, and the electrolytic cell 1 transports the byproduct hydrogen to the gas-liquid separator 2 through a pipeline, the gas-liquid separator 2 is used to remove liquid water in the byproduct hydrogen, and transport the byproduct hydrogen to the washing tower through a pipeline. The washing tower 3 is used to remove the alkaline mist in the by-product hydrogen, and transport the by-product hydrogen to the condenser 4 through a pipeline; the condenser 4 transports the condensed by-product hydrogen to the molecular sieve adsorption tower 5 through a pipeline; the molecular sieve adsorption tower 5 is used to purify the by-product hydrogen, and transport the purified by-product hydrogen to the PSA purification system 7 through the first compressor 6, and the PSA purification system 7 is connected to the second compressor 8 through a pipeline; the second compressor 8 transports the pressurized hydrogen to the storage tank 9 through a pipeline.

[0018] Embodiment 2:

[0019] A system for purifying high-purity hydrogen from byproduct hydrogen of chlor-alkali, comprising a purification process and a purification and compression process; the purification process comprises an electrolytic cell 1, a gas-liquid separator 2, a washing tower 3, a condenser 4 and a molecular sieve adsorption tower 5; the purification and compression process comprises a PSA purification system 7 and a second compressor 8; the electrolytic cell 1 is used for electrolysis to generate byproduct hydrogen, and the electrolytic cell 1 transports the byproduct hydrogen to the gas-liquid separator 2 through a pipeline, the gas-liquid separator 2 is used to remove liquid water in the byproduct hydrogen, and transport the byproduct hydrogen to the washing tower through a pipeline. The washing tower 3 is used to remove the alkaline mist in the by-product hydrogen and transport the by-product hydrogen to the condenser 4 through a pipeline; the condenser 4 transports the condensed by-product hydrogen to the molecular sieve adsorption tower 5 through a pipeline; the molecular sieve adsorption tower 5 is used to purify the by-product hydrogen and transport the purified by-product hydrogen to the PSA purification system 7 through the first compressor 6, and the PSA purification system 7 is connected to the second compressor 8 through a pipeline; the second compressor 8 transports the pressurized hydrogen to the storage tank 9 through a pipeline. The PSA purification system 7 includes a first-level PSA adsorption unit 71 and a second-level PSA adsorption unit 72 connected to each other, the inlet end of the first-level PSA adsorption unit 71 is connected to the first compressor 6 through a pipeline; the outlet ends of the first-level PSA adsorption unit 71 and the second-level PSA adsorption unit 72 are connected to the second compressor 8 through a pipeline.

[0020] The utility model electrolytic cell 1 produces H2 by-product, and after the entrained liquid water is removed by the gas-liquid separator 2, it is transported to the washing tower 3 for washing. The washing tower removes the alkaline mist (OH) - ), after washing is completed, the water in the gas phase is condensed and discharged through the condenser 4, and then the H2O, NaCl and other impurities in the H2 are purified through the molecular sieve adsorption tower 5, and then transported to the purification system through the first compressor 6; the purification system adopts a two-stage adsorption process, and the tail gas that is not adsorbed by the first-stage PSA adsorption unit 71 can continue to be adsorbed by the second-stage PSA adsorption unit 72, thereby improving the yield of H2.

[0021] Furthermore, in another embodiment, a tail gas output pipeline 73 is disposed on the top of the secondary PSA adsorption unit 72 .

[0022] Further, in another embodiment, the outlet pressure of the first compressor 6 is 1 MPa.

[0023] By adopting the above technical solution, the outlet pressure of the first compressor 6 is set to 1 MPa, thereby satisfying the outlet pressure adsorption condition of the PSA purification system 7 .

[0024] Further, in another embodiment, the outlet pressure of the second compressor 8 is 20 MPa or 50 MPa.

[0025] By adopting the above technical solution, the outlet pressure is set to 20Mpa or 50Mpa, so that the purified hydrogen can be stored in two specifications.

[0026] According to the description and drawings of the utility model, those skilled in the art can easily manufacture or use the system of the utility model for purifying high-purity hydrogen from chlor-alkali byproduct hydrogen, and can produce the positive effects recorded in the utility model.

[0027] Unless otherwise specified, in the present invention, the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicating orientation or positional relationships are based on the orientation or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the orientation or positional relationship in the present invention are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood in conjunction with the drawings and according to specific circumstances.

[0028] Unless otherwise specified and limited, in the present invention, the terms "disposed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A system for purifying high-purity hydrogen from chlor-alkali byproduct hydrogen, characterized in that: The invention comprises a purification process and a purification and compression process; the purification process comprises an electrolytic cell (1), a gas-liquid separator (2), a washing tower (3), a condenser (4) and a molecular sieve adsorption tower (5); the purification and compression process comprises a PSA purification system (7) and a second compressor (8); the electrolytic cell (1) is used for electrolysis to generate by-product hydrogen, and the electrolytic cell (1) transports the by-product hydrogen to the gas-liquid separator (2) through a pipeline, the gas-liquid separator (2) is used for removing liquid water in the by-product hydrogen, and transports the by-product hydrogen to the washing tower (3) through a pipeline; the washing The tower (3) is used to remove alkaline mist in the by-product hydrogen and transport the by-product hydrogen to the condenser (4) through a pipeline; the condenser (4) transports the condensed by-product hydrogen to the molecular sieve adsorption tower (5) through a pipeline; the molecular sieve adsorption tower (5) is used to purify the by-product hydrogen and transport the purified by-product hydrogen to the PSA purification system (7) through a first compressor (6); the PSA purification system (7) is connected to the second compressor (8) through a pipeline; the second compressor (8) transports the pressurized hydrogen to the storage tank (9) through a pipeline.

2. A system for purifying high-purity hydrogen from chlor-alkali byproduct hydrogen according to claim 1, characterized in that: The PSA purification system (7) comprises a primary PSA adsorption unit (71) and a secondary PSA adsorption unit (72) which are connected to each other, wherein the inlet end of the primary PSA adsorption unit (71) is connected to the first compressor (6) via a pipeline; and the outlet ends of the primary PSA adsorption unit (71) and the secondary PSA adsorption unit (72) are connected to the second compressor (8) via pipelines.

3. A system for purifying high-purity hydrogen from chlor-alkali byproduct hydrogen according to claim 2, characterized in that: A tail gas output pipeline (73) is arranged at the top of the secondary PSA adsorption unit (72).

4. The system for purifying high-purity hydrogen from chlor-alkali byproduct hydrogen according to claim 1, characterized in that: The outlet pressure of the first compressor (6) is 1 MPa.

5. The system for purifying high-purity hydrogen from chlor-alkali byproduct hydrogen according to claim 1, characterized in that: The outlet pressure of the second compressor (8) is 20 MPa or 50 MPa.

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