Hydrogen gas purification method, hydrogen gas purification system, hydrogen gas regeneration method, and hydrogen gas regeneration system

Abstract

Disclosed is a hydrogen gas purification method for increasing the recovery rate and purity of purified hydrogen gas. According to one aspect, provided is a hydrogen gas purification method comprising purifying a mixed gas produced by an electrolysis method and containing chlorine gas and hydrogen gas.

Description

Hydrogen gas purification method, hydrogen gas purification system, hydrogen gas regeneration method and hydrogen gas regeneration system

[0001] The present disclosure relates to a method for purifying hydrogen gas, and more specifically, to a method for purifying hydrogen gas, a hydrogen gas purification system, a method for regenerating hydrogen gas, and a hydrogen gas regeneration system.

[0002] Electrolysis refers to the phenomenon in which when an electric current is passed through an electrolyte solution, cations are attracted to the (-) pole and anions are attracted to the (+) pole, and are broken down into their constituent substances by gaining or losing electrons. For example, when hydrochloric acid is electrolyzed, a reaction can occur in which chloride ions lose electrons at the (+) pole and are transformed into chlorine gas, and a reaction can occur in which hydrogen ions gain electrons and are transformed into hydrogen gas at the (-) pole. In this way, when hydrochloric acid is electrolyzed, chlorine gas and hydrogen gas are simultaneously produced, making it difficult to recover hydrogen gas, and there was a problem in that stability was reduced due to the possibility of explosion when hydrogen gas and chlorine gas come into contact.

[0003] According to one aspect of the present invention, a method for purifying hydrogen gas is provided, which can safely recover and purify hydrogen gas generated during electrolysis of hydrochloric acid.

[0004] According to another aspect of the present invention, a method for purifying hydrogen gas is provided, which can simultaneously increase the recovery rate of hydrogen gas and the purity of the recovered hydrogen gas.

[0005] According to another aspect of the present invention, a method for purifying hydrogen gas is provided, which can synthesize a foaming agent having various application fields and simultaneously obtain purified hydrogen gas.

[0006] According to another aspect of the present invention, a method for purifying hydrogen gas capable of reusing recovered high-purity hydrogen gas is provided.

[0007] According to another aspect of the present invention, a hydrogen gas purification system capable of safely purifying hydrogen gas generated during electrolysis of hydrochloric acid is provided.

[0008] According to another aspect of the present invention, a hydrogen gas purification system capable of recovering high-purity hydrogen gas is provided.

[0009] According to another aspect of the present invention, a method for regenerating hydrogen gas capable of reusing hydrogen gas in various application fields is provided.

[0010] According to another aspect of the present invention, a hydrogen gas regeneration system for implementing the above hydrogen gas regeneration method is provided.

[0011] The purposes of the present invention are not limited to those mentioned above, and other unmentioned purposes and advantages of the present invention can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the purposes and advantages of the present invention can be realized by the means and combinations thereof described in the specification.

[0012] According to a first aspect of the present invention, a method for purifying hydrogen gas is provided, which comprises purifying a mixed gas containing chlorine gas and hydrogen gas generated by an electrolysis method.

[0013] According to a second aspect of the present invention, the method for purifying hydrogen gas in the first aspect further includes electrolyzing first hydrochloric acid to produce hydrogen gas, first chlorine gas, and second chlorine gas; and obtaining second hydrochloric acid by reacting the first chlorine gas with a hydrazo compound, wherein the chlorine gas may include the second chlorine gas.

[0014] According to a third aspect of the present invention, in the second aspect, the second hydrochloric acid may be circulated and included in the first hydrochloric acid.

[0015] According to a fourth aspect of the present invention, in the third aspect, one cycle consisting of electrolyzing the first hydrochloric acid to produce hydrogen gas, first chlorine gas, and second chlorine gas, and obtaining second hydrochloric acid by reacting the first chlorine gas with a hydrazo compound can be repeatedly performed.

[0016] According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the content of the chlorine gas based on the total volume of the mixed gas may be 200 ppm or less.

[0017] According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the volume ratio of the chlorine gas and the hydrogen gas may be 1:1500 or more and 1:2000 or less.

[0018] According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the mixed gas further includes at least one sub-gas selected from nitrogen gas, oxygen gas, carbon dioxide, hydrogen chloride (HCl(g)), and water (H2O(g)), and the content of the sub-gas may be 30% (v / v) or less based on the total volume of the mixed gas.

[0019] According to an eighth aspect of the present invention, purifying the mixed gas in any one of the first to seventh aspects includes introducing the mixed gas into a scrubber to remove a first gas and obtain a second gas, wherein the first gas may include the chlorine gas. Here, the first gas may further include at least one of hydrogen chloride (HCl(g)) and water (H2O(g)) in addition to the chlorine gas.

[0020] According to a ninth aspect of the present invention, in the eighth aspect, the scrubber may include a first scrubber and a second scrubber connected to the first scrubber, and purifying the mixed gas may include removing the first gas as an absorbent liquid in the first scrubber and cooling the second gas in the second scrubber to obtain a liquid and a third gas.

[0021] According to the tenth aspect of the present invention, in the ninth aspect, the absorbent liquid may include a basic aqueous solution having a pH of 10 or higher.

[0022] According to an eleventh aspect of the present invention, in any one of the eighth to tenth aspects, the content of chlorine gas in the second gas may be less than 20 ppm.

[0023] According to a twelfth aspect of the present invention, purifying the mixed gas in the ninth or tenth aspect further includes removing a fourth gas from the third gas, and the fourth gas may include at least one selected from nitrogen gas, oxygen gas, and carbon dioxide.

[0024] According to the 13th aspect of the present invention, in the 12th aspect, the fourth gas may be removed by an adsorption method.

[0025] According to the fourteenth aspect of the present invention, in the thirteenth aspect, the adsorption method may include a pressure cycling adsorption method.

[0026] According to a fifteenth aspect of the present invention, a first hydrochloric acid is electrolyzed to generate hydrogen gas, a first chlorine gas, a second chlorine gas, and a sub-gas; a second hydrochloric acid is obtained by a reaction of the first chlorine gas with a hydrazo compound; a mixed gas including the second chlorine gas, the hydrogen gas, and the sub-gas is introduced into a first scrubber to remove the first gas and obtain a second gas; the second gas is introduced into the second scrubber and cooled to obtain a liquefied liquid and a third gas; the third gas is introduced into a hydrogen gas collector; And the third gas discharged from the hydrogen gas collector is introduced into a gas adsorption device to remove a fourth gas, wherein the sub-gas includes at least one selected from nitrogen gas, oxygen gas, carbon dioxide, hydrogen chloride (HCl(g)), and water (H2O(g)), the fourth gas includes nitrogen gas, oxygen gas, and carbon dioxide, and the second hydrochloric acid is circulated and included in the first hydrochloric acid. The present invention provides a method for purifying hydrogen gas.

[0027] According to a sixteenth aspect of the present invention, a hydrogen gas purification system is provided, comprising: an electrolysis reaction unit; a gas-liquid separator connected to the electrolysis reaction unit; a scrubber connected to the gas-liquid separator; a hydrogen gas collector connected to the scrubber; and a gas adsorption device connected to the hydrogen gas collector.

[0028] According to the 17th aspect of the present invention, in the 16th aspect, the electrolysis reaction unit includes a reaction tank and an electrolytic tank, and the reaction tank and the electrolytic tank may be non-separated or separated from each other.

[0029] According to the 18th aspect of the present invention, in the 17th aspect, a hydrazo compound may be included inside the reaction tank, and a hydrochloric acid solution may be included inside the electrolytic tank.

[0030] According to the 19th aspect of the present invention, in the 18th aspect, the reaction tank includes a first electrode and a second electrode, and the first electrode and the second electrode can be in direct contact with the hydrazo compound.

[0031] According to a 20th aspect of the present invention, in the 18th aspect, the electrolytic cell includes a third electrode and a fourth electrode, and the third electrode and the fourth electrode can be in direct contact with the hydrochloric acid solution. When the reaction cell and the electrolytic cell are not separated from each other as described in the 16th aspect, the third electrode and the fourth electrode can be the same as the first electrode and the second electrode, respectively. When the reaction cell and the electrolytic cell are separated from each other, the third electrode and the fourth electrode can be different from the first electrode and the second electrode, respectively.

[0032] According to a twenty-first aspect of the present invention, in any one of the sixteenth to twentieth aspects, the scrubber may include a first scrubber for removing first chlorine gas and hydrogen chloride (HCl(g)) and a second scrubber for removing second chlorine gas and water (H2O(g)).

[0033] According to a twenty-second aspect of the present invention, a method for regenerating hydrogen gas is provided, comprising a method for purifying hydrogen gas according to any one of the first to fifteenth aspects.

[0034] According to the 23rd aspect of the present invention, the method for regenerating the hydrogen gas in the 22nd aspect may include reacting the purified hydrogen gas with oxygen gas to produce hydrogen peroxide.

[0035] According to the 24th aspect of the present invention, a hydrogen gas regeneration system is provided, including a hydrogen gas purification system according to any one of the 16th to 21st aspects.

[0036] According to the 25th aspect of the present invention, a hydrogen gas regeneration system can be provided, further comprising a hydrogen peroxide generating device connected to the hydrogen gas purification system in the 24th aspect.

[0037] The solutions to the above problems do not enumerate all features of the present invention. The various features of the present invention, along with their corresponding advantages and effects, can be understood in more detail by referring to the detailed description below.

[0038] According to one aspect of the present invention, a method for purifying hydrogen gas can be implemented, which can safely recover and purify hydrogen gas generated during electrolysis of hydrochloric acid.

[0039] According to another aspect of the present invention, a method for purifying hydrogen gas can be implemented that can increase the recovery rate and purity of hydrogen gas.

[0040] According to another aspect of the present invention, a method for purifying hydrogen gas can be implemented that can simultaneously obtain purified hydrogen gas and a foaming agent with various applications.

[0041] According to another aspect of the present invention, purified hydrogen gas can be applied to various industrial fields to significantly improve manufacturing costs and process efficiency.

[0042] In addition to the aforementioned effects, specific effects of the present invention are described below along with specific details for implementing the invention. Furthermore, the effects of the present invention are not limited to the effects described above and can be readily achieved using the means and combinations thereof described in the specification.

[0043] Figure 1 is a flow chart showing a method for purifying hydrogen gas according to one embodiment of the present invention.

[0044] Figure 2 is a flow chart showing a method for purifying hydrogen gas according to another embodiment of the present invention.

[0045] Figure 3 is a flow chart showing a hydrogen gas purification system of one embodiment of the present invention.

[0046] Figure 4 is an electrolysis reaction unit according to one embodiment of the present invention.

[0047] Figure 5 is a hydrogen gas purification system according to another embodiment of the present invention.

[0048] Figure 6 is an electrolysis reaction unit according to another embodiment of the present invention.

[0049] Figure 7 is a hydrogen gas purification system according to another embodiment of the present invention.

[0050] Figure 8 is a flow chart showing a hydrogen gas regeneration system according to one embodiment of the present invention.

[0051] Figure 9 is a flow chart showing a hydrogen gas regeneration system according to another embodiment of the present invention.

[0052] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0053] In this specification, “At least one of a, b and c” is defined as one or more selected from the group consisting of a, b and c.

[0054] The term "connection" as used herein means not only that a component is directly connected to another component, but also includes an indirect connection where another component is interposed between the two components.

[0055] If a term expressed as a component in this specification includes a functional expression, it may be defined to encompass not only the function in question but also other functions that can be clearly understood by a person skilled in the art.

[0056] When multiple embodiments are described in this specification, the embodiments may be organically combined, and the effects of the present invention may be defined to include effects that arise when the embodiments are organically combined. For example, even if Embodiments 1 and 2 are independently described in this specification, unless the context clearly indicates otherwise, effects that arise when Embodiments 1 and 2 are organically combined may also be included in the effects of the present invention.

[0057] The numerical range indicated by the term "to" in this specification refers to a numerical range that includes the values ​​stated before and after the term as the lower and upper limits, respectively. For example, if "a" and "b" are stated in the specification, it can be understood that "a" and "b" are stated.

[0058] In the present specification, when multiple numerical values ​​are disclosed as the upper and lower limits of any numerical range, the numerical range disclosed in the present specification can be understood as any numerical range that has any one of the multiple lower limit values ​​and any one of the multiple upper limit values ​​as the lower limit value and the upper limit value, respectively. For example, when a or more, or b or more; and c or less or d or less are described, it can be understood that a or more and c or less, a or more and d or less, b or more and c or less, or b or more and d or less are described.

[0059] As used herein, terms such as "about" or "substantially" mean a reasonable amount of variation from the term that does not significantly alter the final result. These terms may be interpreted to include a variation of at least ±5% or at least ±10%, provided that such variation does not alter the meaning of the term and render it invalid.

[0060] Previously, electrolysis of hydrochloric acid produced both chlorine and hydrogen gas simultaneously, making it difficult to recover the hydrogen gas. Furthermore, the potential for hydrogen and chlorine to explode led to safety issues. The explosion of a mixture of hydrogen and chlorine gases stemmed from the high concentration of chlorine gas, which reacts with hydrogen. If most of the chlorine gas, which can react with hydrogen, were removed through other routes, the risk of explosion could be significantly reduced.

[0061] Meanwhile, azodicarbonamide (ADCA), a type of azo compound, is currently the most widely used foaming agent. The foaming agent is an additive that is mixed with synthetic resin to produce a porous foam. Azodicarbonamide is self-extinguishing and non-toxic, and is used for the purposes of lightweighting, cushioning, buoyancy, absorbency, decoration, touch, cost reduction, and dimensional stability of the product. In addition, the foaming of the above azodicarbonamide is mainly used for polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), rubber, ethylene-vinyl acetate copolymer (EVA), polystyrene (PS), polyurethane (PU), transparent silicone, etc. In addition, the azodicarbonamide is known as an excellent blowing agent because it rapidly generates nitrogen gas when heated, and its decomposition products are non-flammable and non-toxic. Furthermore, the azodicarbonamide is also used as a heat-regulating agent or bleaching agent for wheat flour (45 ppm or less, US FDA standards). Such useful azodicarbonamide (ADCA) can be produced, for example, by the reaction of hydrazodicarbonamide (HDCA) and chlorine gas.

[0062] According to one aspect of the present invention, a method for purifying hydrogen gas is provided, which comprises purifying a mixed gas containing chlorine gas and hydrogen gas generated by an electrolytic method. Specifically, by using a majority of the chlorine gas generated by electrolyzing hydrochloric acid as chlorine gas for oxidizing a hydrazo compound, the content of chlorine gas in the mixed gas containing hydrogen gas and chlorine gas to be purified can be significantly reduced. Accordingly, the risk of an explosive reaction occurring during the electrolysis of hydrochloric acid can be significantly reduced, while at the same time, the recovery rate and purity of the hydrogen gas to be purified can be further increased.

[0063] According to another aspect of the present invention, by re-electrolyzing hydrochloric acid, which is generated as a by-product in the process of synthesizing an azo compound, the efficiency of the hydrogen gas purification process can be improved, thereby significantly reducing the process cost, and a useful material, a foaming agent, can also be synthesized at the same time.

[0064] 1. Method for purifying hydrogen gas

[0065] A method for purifying hydrogen gas according to the present invention comprises purifying a mixed gas containing chlorine gas and hydrogen gas generated by an electrolytic method. Purifying the mixed gas, as used herein, is not particularly limited and may include any process for increasing the purity of hydrogen gas in the mixed gas, and more specifically, may include a process for removing gases other than hydrogen gas using various methods.

[0066] The mixed gas according to the present invention includes chlorine gas and hydrogen gas generated by electrolysis of hydrochloric acid. Specifically, the mixed gas may further include at least one of nitrogen gas, oxygen gas, carbon dioxide, hydrogen chloride (HCl(g)), and water (H2O(g)), and specifically may include nitrogen gas, oxygen gas, carbon dioxide, hydrogen chloride (HCl(g)), and water (H2O(g)). Here, the nitrogen gas and oxygen gas may be gases introduced from the air, the carbon dioxide may be a gas generated by a byproduct of the electrolysis process, the hydrogen chloride (HCl(g)) may be a gas generated by a reaction of chlorine gas with water, and the water (H2O(g)) may be derived from a reactant of the electrolysis reaction.

[0067] In some examples, the above electrolysis method may be a method in which chloride ions lose electrons at the (+) pole and are converted into chlorine gas, and hydrogen ions gain electrons at the (-) pole and are converted into hydrogen gas.

[0068] Hereinafter, the configuration of the present invention will be described in more detail with reference to Fig. 1.

[0069] Figure 1 is a flow chart showing a method for purifying hydrogen gas according to one embodiment of the present invention.

[0070] Referring to FIG. 1, a method for purifying hydrogen gas (S10) of one embodiment of the present invention may include electrolyzing first hydrochloric acid to generate hydrogen gas and first and second chlorine gases (S11), obtaining second hydrochloric acid by a reaction of the first chlorine gas and a hydrazo compound (S12), purifying a mixed gas containing chlorine gas and hydrogen gas, which is generated by the electrolysis method, including the second chlorine gas (S13), and obtaining purified hydrogen gas (S14).

[0071] (S11) Electrolyze the first hydrochloric acid to produce hydrogen gas and first and second chlorine gases.

[0072] Meanwhile, the reaction for electrolyzing the first hydrochloric acid can proceed according to the following reaction formula 1.

[0073] [Reaction Formula 1]

[0074] 2HCl→H2+Cl2

[0075] The first chlorine gas and the second chlorine gas are in a mixed gaseous state, but can travel through different routes. For example, the first chlorine gas can be used immediately as a reactant to react with a hydrazo compound as soon as it is generated by electrolysis of the first hydrochloric acid, and the second chlorine gas can be a gas to be purified together with the hydrogen gas generated by electrolysis without being used as a reactant to react with the hydrazo compound.

[0076] In some embodiments of the present invention, the content of the first chlorine gas relative to the total chlorine gas produced by electrolysis of the first hydrochloric acid may be higher than the content of the second chlorine gas. According to some embodiments of the present invention, the content of the first chlorine gas relative to the total chlorine gas produced by electrolysis of the first hydrochloric acid may be higher than the content of the second chlorine gas, thereby reducing the content of the second chlorine gas mixed with the hydrogen gas, thereby further reducing the risk of explosion. Accordingly, the stability of the hydrogen gas purification process may be further improved.

[0077] In some embodiments of the present invention, the volume ratio of the first chlorine gas and the second chlorine gas (first chlorine gas: second chlorine gas) may be 1:0.0001 or more and 1:0.0010 or less, specifically 1:0.0001 or more and 1:0.0005 or less, and more specifically 1:0.0001 or more and 1:0.0003 or less. According to some embodiments of the present invention, when the volume ratio of the first chlorine gas and the second chlorine gas satisfies the numerical range, the possibility of explosion that may occur due to the reaction of hydrogen gas generated by electrolysis with a small amount of second chlorine gas is significantly reduced, and at the same time, the efficiency of producing an azo compound can be further improved by sufficiently oxidizing the hydrazo compound through the first chlorine gas.

[0078] In some embodiments of the present invention, the content of the second chlorine gas may be 200 ppm or less, 100 ppm or less, 90 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, 10 ppm or less, or 1 ppm or less, based on the total volume of the mixed gas, and specifically may be 0.001 ppm or more and any one of the plurality of arbitrary values. According to some embodiments of the present invention, since the content of the second chlorine gas satisfies the numerical range, the possibility of explosion that may occur when the hydrogen gas generated by electrolysis and the second chlorine gas react is significantly reduced, and at the same time, the reaction efficiency of generating an azo compound by the reaction of the hydrazo compound and the first chlorine gas can be further increased. For example, the content of the second chlorine gas can be measured by capturing the second chlorine gas in a cylinder and then using GC / TCD (Gas Chromatography / Thermal Conductivity Detector).

[0079] Meanwhile, the yield of hydrogen gas can be defined as the number of moles of hydrogen gas produced relative to the number of moles of the first hydrochloric acid (liquid). According to the above reaction formula 1, if the yield of hydrogen gas is 100%, 1 mole of hydrogen gas can be produced per 2 moles of the first hydrochloric acid.

[0080] [Formula 1]

[0081] Hydrogen gas yield (%) = [(moles of hydrogen gas produced (mol) × 2) / (moles of first hydrochloric acid introduced (mol))] × 100

[0082] In some embodiments of the present invention, the yield of hydrogen gas produced by the electrolysis of the first hydrochloric acid may be 90% or more, 91% or more, 92% or more, 93% or more, or 94% or more, and specifically, may be 90 to 95%, 91 to 95%, 92 to 95%, 93 to 95%, or 94 to 95%. Here, the yield of hydrogen gas produced by the electrolysis of the first hydrochloric acid refers to the ratio of hydrogen gas produced to the content of the first hydrochloric acid introduced, and a higher yield may mean that the first hydrochloric acid is electrolyzed to produce hydrogen gas corresponding to the theoretical mole. For example, the yield of hydrogen gas may be analyzed using GC (Gas chromatography). According to some embodiments of the present invention, since the yield of hydrogen gas produced by the electrolysis of the first hydrochloric acid satisfies the above numerical range, the purity of the hydrogen gas that is ultimately purified may be further increased.

[0083] (S12) A second hydrochloric acid is obtained by the reaction of the first chlorine gas and the hydrazo compound.

[0084] In some embodiments of the present invention, the method for purifying hydrogen gas may include (S12) obtaining a second hydrochloric acid by reacting the first chlorine gas with a hydrazo compound. Specifically, according to the following reaction scheme 2, the first chlorine gas may react with a hydrazo compound to produce an azo compound and a second hydrochloric acid. For example, the hydrazo compound may be hydrazodicarbonamide (HDCA), and the azo compound may be azodicarbonamide (ADCA).

[0085] [Reaction Formula 2]

[0086] HDCA+2Cl2(g)→ADCA+2HCl(l)

[0087] According to some embodiments of the present invention, the first chlorine gas generated by electrolyzing the first hydrochloric acid can be directly used as a reactant required for the synthesis process of the azo compound, thereby generating the azo compound, and the second hydrochloric acid generated according to the reaction formula 2 can be electrolyzed again, thereby generating hydrogen gas.

[0088] In some embodiments of the present invention, the second hydrochloric acid may be circulated and included in the first hydrochloric acid. Here, the second hydrochloric acid being circulated and included in the first hydrochloric acid may mean that, similarly to the first hydrochloric acid, the second hydrochloric acid is electrolyzed to produce hydrogen gas, first chlorine gas, and second chlorine gas. According to some embodiments of the present invention, since the second hydrochloric acid is circulated and included in the first hydrochloric acid, the reaction of producing an azo compound and the reaction of producing hydrogen gas due to the electrolysis of hydrochloric acid are performed in one cycle, so that hydrochloric acid that produces hydrogen gas to be purified can be continuously supplied. Accordingly, the efficiency of the synthesis process of an azo compound and the efficiency of the purification process of hydrogen gas can be further increased on a large scale.

[0089] In some embodiments of the present invention, one cycle (C1) consisting of electrolyzing the first hydrochloric acid to produce hydrogen gas, first chlorine gas, and second chlorine gas, and obtaining second hydrochloric acid by reacting the first chlorine gas with a hydrazo compound may be repeatedly performed. According to some embodiments of the present invention, one cycle (C1) consisting of electrolyzing the first hydrochloric acid to produce hydrogen gas, first chlorine gas, and second chlorine gas, and obtaining second hydrochloric acid by reacting the first chlorine gas with a hydrazo compound is repeatedly performed, so that the reaction for producing an azo compound and the reaction for producing hydrogen gas by electrolysis of hydrochloric acid are performed in one cycle, and hydrochloric acid that produces hydrogen gas to be purified can be continuously supplied. Accordingly, the efficiency of the synthesis process of an azo compound and the efficiency of the purification process of hydrogen gas can be further increased on a large scale.

[0090] In some embodiments of the present invention, the weight ratio of the obtained second hydrochloric acid to the weight of the first hydrochloric acid subjected to electrolysis may be 80% or more, 90% or more, specifically 100%. In this case, the weight ratio of the obtained second hydrochloric acid to the weight of the first hydrochloric acid subjected to electrolysis means the ratio of the amount of the recovered second hydrochloric acid to the amount of the first hydrochloric acid input, i.e., the recovery rate of the hydrochloric acid. When the weight ratio of the obtained second hydrochloric acid to the weight of the first hydrochloric acid subjected to electrolysis satisfies the above numerical range, the amount of hydrochloric acid newly input for generating hydrogen gas can be reduced. Accordingly, the efficiency of the synthesis process of an azo compound and the efficiency of the purification process of hydrogen gas can be further improved on a large scale.

[0091] In some examples, the above cycle can be repeated infinitely.

[0092] In some examples, the above cycle may be [(S11)-(S12)]n (where n is an integer greater than or equal to the number of cycles) n cycles. The number of cycles n may be 10 or more, specifically 10 to 50, and more specifically 10 to 30. In this case, by satisfying the number of cycles within the above numerical range, the efficiency of the synthesis process of the azo compound and the efficiency of the purification process of the hydrogen gas can be further increased in a large scale.

[0093] In some embodiments of the present invention, the hydrogen gas purification method can satisfy the following equation 2.

[0094] [Formula 2]

[0095] 0.9 ≤ A / B ≤1 (0.8≤A≤1, 0.8≤B≤1)

[0096] Here, A is the electrolysis rate of hydrochloric acid, which is defined as the molar ratio of chlorine gas actually produced to the theoretical moles of chlorine gas that hydrochloric acid can produce relative to the applied electricity (actual moles of chlorine gas produced / theoretically moles of chlorine gas produced). B is the recovery rate of hydrochloric acid.

[0097] The theoretical number of moles of chlorine gas produced can be calculated by the following equation 3, and the actual number of moles of chlorine gas produced is measured using a detector tube.

[0098] [Formula 3]

[0099] Theoretical number of moles of chlorine gas produced (mol) × 96500 / 3600 (C / mol·s) × 2 = Amount of electricity applied (A)

[0100] The above B is as defined above as the recovery rate of hydrochloric acid.

[0101] By satisfying the above equation 3, the amount of electrical power applied can be adjusted to an appropriate range, thereby maximizing the efficiency of the azo compound synthesis process and the efficiency of the hydrogen gas purification process.

[0102] If the value of the above A / B is less than 0.9, the electrolysis rate of hydrochloric acid with respect to the recovery rate of hydrochloric acid may not be maximized, resulting in loss of hydrochloric acid, and the production efficiency of hydrogen and azo compounds for the recovered hydrochloric acid may also be reduced.

[0103] (S13) Purifying the mixed gas containing the chlorine gas and the hydrogen gas, which is generated by the electrolysis method, and

[0104] In some embodiments of the present invention, the method for purifying hydrogen gas may include (S13) purifying a mixed gas comprising chlorine gas containing the second chlorine gas and the hydrogen gas, which are generated by an electrolysis method. According to some embodiments of the present invention, by using most of the chlorine gas generated by electrolysis of hydrochloric acid as chlorine gas for oxidizing a hydrazo compound, the content of chlorine gas in the mixed gas comprising hydrogen gas and chlorine gas to be purified can be significantly reduced. Accordingly, the risk of an explosive reaction occurring during the electrolysis of hydrochloric acid can be significantly reduced, and at the same time, the recovery rate and purity of the hydrogen gas to be purified can be further increased. In addition, by reusing hydrochloric acid, which is generated as a byproduct during the synthesis of an azo compound, as a reactant in the electrolysis reaction, the efficiency of the hydrogen gas purification process can be improved, thereby significantly reducing the process cost, and a useful material, a blowing agent, can be synthesized at the same time. Accordingly, the advantage of being able to infinitely reuse hydrochloric acid can be realized, which can significantly reduce the manufacturing cost of the process.

[0105] In some embodiments of the present invention, the content of the chlorine gas based on the total volume of the mixed gas may be 200 ppm or less, 100 ppm or less, 90 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, 10 ppm or less, or 1 ppm or less, and specifically may be 0.001 ppm or more and any one of the above-described multiple numerical values ​​or less. According to some embodiments of the present invention, since the content of the chlorine gas satisfies the numerical range, the possibility of explosion that may occur when the hydrogen gas generated by electrolysis and the chlorine gas react is significantly reduced, and at the same time, the reaction efficiency of generating an azo compound by the reaction of the hydrazo compound and the first chlorine gas can be further increased. For example, the chlorine gas may be the same as the second chlorine gas described above.

[0106] In some embodiments of the present invention, the volume ratio of the chlorine gas and the hydrogen gas may be 1:1500 or more and 1:2000 or less, 1:1600 or more and 1:1900 or less, 1:1600 or more and 1:1800 or less, or 1:1600 or more and 1:1700 or less. Here, the chlorine gas and the hydrogen gas may be gases to be purified and may be transferred to a purification facility through a gas-liquid separator to be described later. According to some embodiments of the present invention, since the volume ratio of the chlorine gas and the hydrogen gas satisfies the numerical range, the possibility of an explosion that may occur due to the reaction of the hydrogen gas and the chlorine gas generated by the electrolysis may be significantly reduced. In some examples, the reason why the volume ratio of the chlorine gas and the hydrogen gas may be adjusted to the numerical range may be because most of the chlorine gas generated by the electrolysis immediately reacts with the hydrazo compound. Accordingly, the content of the chlorine gas to be purified may be an extremely small amount in the ppm unit as described above. For example, the volume ratio of the chlorine gas and the hydrogen gas can be analyzed by collecting the chlorine gas and the hydrogen gas in a cylinder using GC / TCD (Gas Chromatography / Thermal Conductivity Detector) and then calculating the content of each gas as a volume %.

[0107] In some embodiments of the present invention, the mixed gas may further include one or more sub-gases selected from nitrogen gas, oxygen gas, carbon dioxide, hydrogen chloride (HCl(g)), and water (H2O(g)). Here, the sub-gas may be a gas to be removed to increase the purity of the hydrogen gas. Specifically, the content of the sub-gas may be 30% (v / v) or less, specifically 25% (v / v) or less, and more specifically 20% (v / v) to 25% (v / v) based on the total volume of the mixed gas. According to some embodiments of the present invention, when the content of the sub-gas satisfies the numerical range, the purity of the hydrogen gas may be further increased, and the regeneration efficiency of the hydrogen gas may be further increased.

[0108] In some examples, the content of the oxygen gas may be 0.1 to 1.1% (v / v) based on the total volume of the mixed gas, the content of the nitrogen gas may be 1.9 to 2.9% (v / v), the content of the water (H2O(g)) may be 10 to 16% (v / v), the content of the carbon dioxide may be 8 to 16% (v / v), and the content of the hydrogen chloride (HCl(g)) may be 0.02% or less (v / v). However, the technical idea of ​​the present invention is not limited thereto, and the content of the sub-gas may be variously modified.

[0109] In some examples, the method for purifying the mixed gas is not particularly limited and may be any one method selected from the group consisting of physical removal methods, chemical removal methods, and combinations thereof commonly used in the relevant technical field. Specifically, the physical removal method may be a method for removing gases other than hydrogen gas from the mixed gas through an adsorption method or the like, and the chemical removal method is not particularly limited and may be a method for removing gases other than hydrogen gas from the mixed gas through various chemical reactions or absorbents.

[0110] In some embodiments of the present invention, purifying the mixed gas may include introducing the mixed gas into a scrubber to remove the first gas and obtain a second gas. Specifically, the first gas may include the chlorine gas. Here, the chlorine gas may include the second chlorine gas described above.

[0111] The scrubber according to the present invention may include a cooling scrubber, and specifically, may include a wet scrubber that removes chlorine gas and hydrogen chloride (HCl(g)) with an absorbent liquid, and a cooling scrubber connected to the wet scrubber. Specifically, the cooling scrubber may be a device that removes chlorine gas and water (H2O(g)) in the mixed gas by cooling and liquefying them, and the wet scrubber may be a device that removes chlorine gas to be removed by dissolving it in an absorbent liquid. According to some embodiments of the present invention, since the scrubber includes the wet scrubber and the cooling scrubber, the removal efficiency for chlorine gas can be further increased, and the recovery rate and purity of recovered hydrogen gas can be further increased.

[0112] In some embodiments of the present invention, the scrubber may include a first scrubber and a second scrubber connected to the first scrubber. Here, the first scrubber may be the wet scrubber, and the second scrubber may be the cooling scrubber. Specifically, purifying the mixed gas may include removing the first gas with an absorbent liquid in the first scrubber and cooling the second gas in the second scrubber to obtain a liquid and a third gas. Here, the liquid may be a liquefied portion of the second gas.

[0113] In some embodiments of the present invention, the chlorine gas and water (H2O(g)) in the mixed gas can be removed at atmospheric pressure conditions and -80 to -10°C in the cooling scrubber (or the second scrubber). According to some embodiments of the present invention, by cooling the chlorine gas and water (H2O(g)) in the mixed gas in the cooling scrubber under the pressure and temperature conditions, the chlorine gas and water (H2O(g)) can be cooled more effectively, thereby further increasing the purity and recovery rate of hydrogen gas.

[0114] According to some embodiments of the present invention, in the wet scrubber (or the first scrubber), the absorbent may include an alkaline aqueous solution having a pH of 8 or higher, an alkaline aqueous solution having a pH of 9 or higher, specifically an alkaline aqueous solution having a pH of 10 or higher, and more specifically an aqueous solution having a pH of 10 to 14. According to some embodiments of the present invention, when the pH of the alkaline aqueous solution satisfies the above numerical range, chlorine gas among the gases introduced into the wet scrubber may be more easily dissolved in the absorbent, thereby further increasing the recovery rate and purity of hydrogen gas. In some examples, the alkaline aqueous solution may include at least one of a monovalent base, a divalent base, and a trivalent base, specifically at least one of a monovalent base and a divalent base, and more specifically a monovalent base. According to some embodiments of the present invention, by including at least one of the monovalent base and the divalent base in the basic aqueous solution, an effect of significantly lowering the concentration of residual chlorine after passing through the scrubber can be achieved.

[0115] Specifically, the basic aqueous solution is NaOH, KOH, Li(OH), RbOH, FrOH, NH4OH, CsOH, Be(OH)2, Mg(OH)2, Ca(OH)2, Ba(OH)2, Ra(OH)2, Sr(OH) 2, Cu(OH)2, Zn(OH)2, Ni(OH)2, Mn(OH)2, Sn(OH) 2, Mo(OH) 2, Fe(OH) 3, Al(OH) 3, La(OH) 3, Cr(OH) 3, and It may include at least one selected from the group consisting of Cu2(OH)3.

[0116] In some embodiments of the present invention, based on the total weight of the basic aqueous solution, the content of the above-mentioned base may be 0.1 wt% or more, 1 wt% or more, 5 wt% or more, 10 wt% or more, 20 wt% or more, 30 wt% or more, 40 wt% or more, 50 wt% or more, 60 wt% or more, 70 wt% or more, 80 wt% or more, 90 wt% or more, or 99 wt% or more; 0.1 wt% or less, 1 wt% or less, 5 wt% or less, 10 wt% or less, 20 wt% or less, 30 wt% or less, 40 wt% or less, 50 wt% or less, 60 wt% or less, 70 wt% or less, 80 wt% or less, 90 wt% or less, or 99 wt% or less; or any one of the plurality of lower limits may be at least one and any one of the plurality of upper limits may be at most one. According to some embodiments of the present invention, when the content of the above-described base based on the total weight of the basic aqueous solution satisfies the above numerical range, the concentration of residual chlorine after passing through the scrubber can be further reduced.

[0117] In some embodiments of the present invention, the content of chlorine gas in the second gas may be less than 20 ppm, 19 ppm or less, 18 ppm or less, 17 ppm or less, 16 ppm or less, 15 ppm or less, 14 ppm or less, 13 ppm or less, 12 ppm or less, 11 ppm or less, 10 ppm or less, 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, or 1 ppm or less, and more specifically, 0.01 ppm or less. According to some embodiments of the present invention, when the content of chlorine gas in the second gas satisfies the above numerical range, corrosion of subsequent process equipment, such as a hydrogen gas collector and a gas adsorption device, can be effectively prevented.

[0118] In some embodiments of the present invention, purifying the mixed gas may further include removing a fourth gas from the third gas. In some examples, the third gas is a gas discharged from the cooling scrubber (or the second scrubber) and may include at least one selected from hydrogen gas, nitrogen gas, carbon dioxide, and oxygen gas, and may specifically include hydrogen gas, nitrogen gas, carbon dioxide, and oxygen gas. In some examples, the fourth gas is a gas to be removed and may include at least one selected from nitrogen gas, oxygen gas, and carbon dioxide, and may specifically include all of nitrogen gas, oxygen gas, and carbon dioxide, and may more specifically be composed of nitrogen gas, oxygen gas, and carbon dioxide.

[0119] In some embodiments of the present invention, a hydrogen gas holder commonly used in the art may be used to capture hydrogen gas among the third gases. The hydrogen gas holder may be a storage tank that temporarily stores hydrogen gas among the third gases. If necessary, the hydrogen gas may be automatically discharged when the internal pressure exceeds a predetermined pressure.

[0120] In another embodiment of the present invention, a membrane separation method commonly used in the art may be used to capture and concentrate hydrogen gas among the third gases. Specifically, the membrane separation method may be a method of separating and concentrating hydrogen gas using a polymer membrane. In some examples, the polymer membrane is not particularly limited and may include at least one selected from the group consisting of polysulfone, polyimide, and polybenzimidazole as a membrane having excellent selectivity for hydrogen gas. The hydrogen gas separated and concentrated through the membrane separation method may be in a mixed state with the fourth gas.

[0121] In some embodiments of the present invention, purifying the mixed gas may include removing the fourth gas by an adsorption method. The adsorption method may be a method of removing the fourth gas using an adsorbent commonly used in the relevant technical field. According to some embodiments of the present invention, by removing the fourth gas by an adsorption method, the recovery rate and purity of hydrogen gas can be further increased.

[0122] In some embodiments of the present invention, the adsorption method may include a pressure swing adsorption (PSA) method. Here, the pressure swing adsorption method may be a method in which a raw material gas passes through an adsorption tower filled with an adsorbent at a high pressure, and components with high selectivity are adsorbed on the adsorbent and gases with low selectivity are discharged to the outside of the adsorption tower. Specifically, the raw material gas may be a gas discharged from the hydrogen gas collector. According to some embodiments of the present invention, since the adsorption method includes a pressure swing adsorption (PSA) method, the removal efficiency of the fourth gas is further increased, and the recovery rate and purity of the hydrogen gas can be further increased.

[0123] In some examples, the adsorbent is not particularly limited and may include at least one selected from the group consisting of zeolite, activated carbon, mesoporous carbon, alumina, and silica. Specifically, the adsorbent may be packed in a single layer or multiple layers. For example, zeolite may be used under conditions of 1 to 7 atm to remove oxygen gas, activated carbon or zeolite may be used under conditions of 0.06 to 7 atm to remove nitrogen gas, and zeolite, silica, alumina, etc. may be used under conditions of 0.1 atm or less to remove carbon dioxide.

[0124] In some examples, the pressure swing adsorption method is performed at an adsorption pressure of 1 bar or more, 2 bar or more, 3 bar or more, 4 bar or more, 5 bar or more, 6 bar or more, 7 bar or more, 8 bar or more, 9 bar or more, 10 bar or more, 11 bar or more, 12 bar or more, 13 bar or more, 14 bar or more, 15 bar or more, 16 bar or more, 17 bar or more, 18 bar or more, 19 bar or more, 20 bar or more, 21 bar or more, 22 bar or more, 23 bar or more, 24 bar or more, or 25 bar or more; 2 bar or less, 3 bar or less, 4 bar or less, 5 bar or less, 6 bar or less, 7 bar or less, 8 bar or less, 9 bar or less, 10 bar or less, 11 bar or less, 12 bar or less, 13 bar or less, 14 bar or less, 15 bar or less, 16 bar or less, 17 bar or less, 18 bar or less, 19 bar or less, 20 bar or less, 21 bar or less, 22 bar or less, 23 bar or less, 24 bar or less, or 25 bar or less; or any one or more of the plurality of lower limits and any one or more of the plurality of upper limits, and specifically may be 1 to 25 bar.

[0125] In some examples, the pressure swing adsorption method may have a desorption pressure of 0.01 bar or more, 0.1 bar or more, 1.0 bar or more, 1.5 bar or more, 1.8 bar or more, or 2 bar or more; 0.1 bar or less, 1.0 bar or less, 1.5 bar or less, 1.8 bar or less, or 2 bar or less; or any one or more of the plurality of lower limits and any one or less of the plurality of upper limits, and specifically may be 0.01 to 2 bar. Specifically, when the process conditions of the pressure swing adsorption method satisfy the pressure condition range, sub-gases other than hydrogen gas can be effectively removed by the adsorption method. In addition, the gas adsorption device can be reused by controlling the desorption pressure.

[0126] (S14) Obtain purified hydrogen gas

[0127] In some embodiments of the present invention, the method for purifying hydrogen gas may include obtaining purified hydrogen gas.

[0128] In some examples, the purity of the purified hydrogen gas may be 90% or greater, 91% or greater, 92% or greater, 93% or greater, 94% or greater, 95% or greater, 96% or greater, 97% or greater, 98% or greater, 99% or greater, 99.00 to 99.99%, 99.80 to 99.99%, or 99.90 to 99.99%.

[0129] The purity of the above hydrogen gas refers to the ratio (%) of the volume of hydrogen gas to the volume of the total gas obtained.

[0130] Specifically, the purity of the purified hydrogen gas can be measured using GC (Gas Chromatography).

[0131] In some examples, the weight ratio of the azo compound produced and the purified hydrogen gas may be 1000:10 to 1000:30, 1000:15 to 1000:25, 1000:17 to 1000:23, or 1000:17 to 1000:20. For example, the weight ratio of the azo compound produced and the purified hydrogen gas may be analyzed by collecting the gas in a cylinder and then converting the volume ratio measured by GC / TCD (Gas Chromatography / Thermal Conductivity Detector) into a weight ratio.

[0132] In some examples, the obtained purified hydrogen gas may be at least 80 mol%, at least 85 mol%, at least 90 mol%, at least 95 mol%, or at least 99 mol%, based on the total moles of hydrogen gas contained in the mixed gas, and specifically, any one or more of the plurality of lower limits may be at most 99.9 mol%. For example, the obtained purified hydrogen gas may be collected in a cylinder based on the total moles of hydrogen gas contained in the mixed gas, and then analyzed using GC / TCD (Gas Chromatography / Thermal Conductivity Detector).

[0133] In some examples, the molar ratio of the introduced hydrazo compound to the purified hydrogen gas may be 1:0.9 to 1:1. The hydrazo compound reacts with chlorine gas electrolyzed from hydrochloric acid to produce an azo compound and hydrochloric acid, and the produced hydrochloric acid is electrolyzed again to produce chlorine and hydrogen, so that purified hydrogen gas can be obtained in an amount equal to the number of moles of the introduced hydrazo compound.

[0134] Figure 2 is a flow chart illustrating a hydrogen gas purification method according to another embodiment of the present invention. Parts that are repeated in the description above are briefly explained or omitted.

[0135] Referring to FIG. 2, a method for purifying hydrogen gas (S20) of another embodiment of the present invention may include electrolyzing first hydrochloric acid to generate hydrogen gas, first chlorine gas, second chlorine gas, and a sub-gas (S21), obtaining second hydrochloric acid by a reaction of the first chlorine gas and a hydrazo compound (S22), introducing a mixed gas including the second chlorine gas and the hydrogen gas into a first scrubber to remove the first gas and obtain a second gas (S23), introducing the second gas into the second scrubber and cooling it to obtain a liquefied liquid and a third gas (S24), introducing the third gas into a hydrogen gas collector (S25), introducing the third gas discharged from the hydrogen gas collector into a gas adsorption device to remove a fourth gas (S26), and obtaining purified hydrogen gas (S27). Here, the sub-gas includes at least one selected from nitrogen gas, oxygen gas, carbon dioxide, hydrogen chloride (HCl(g)), and water (H2O(g)), and specifically may include all of nitrogen gas, oxygen gas, carbon dioxide, hydrogen chloride (HCl(g)), and water (H2O(g)). And the second hydrochloric acid is circulated and included in the first hydrochloric acid.

[0136] As described above, the first scrubber may be a wet scrubber, and the second scrubber may be a cooling scrubber. According to some embodiments of the present invention, by connecting the first scrubber and the second scrubber, the removal efficiency of chlorine gas may be increased, thereby further increasing the recovery rate and purity of hydrogen gas.

[0137] 2. Hydrogen gas purification system

[0138] Figure 3 is a flow chart showing a hydrogen gas purification system of one embodiment of the present invention.

[0139] Figure 4 is an electrolysis reaction unit according to one embodiment of the present invention.

[0140] A hydrogen gas purification system (1000) according to the present invention includes an electrolysis reaction unit (200), a gas-liquid separator (250), a scrubber (300), a hydrogen gas collector (400), and a gas adsorption device (500).

[0141] Electrolysis reaction unit (200)

[0142] Referring to FIGS. 3 and 4, the electrolysis reaction unit (200, Electrolysis reactor) according to the present invention may be a reactor in which a reaction in which an azo compound is generated by a reaction between a hydrazo compound and chlorine gas (the first chlorine gas) and a reaction in which hydrochloric acid is electrolyzed occur. Here, the reaction in which the azo compound is generated may occur in a reaction tank, and the reaction in which the hydrochloric acid is electrolyzed may occur in an electrode tank. At this time, the electrolytic tank and the reaction tank are not separated, and the reaction in which the azo compound is generated and the reaction in which hydrochloric acid is electrolyzed may proceed using the same electrode.

[0143] The electrolysis reaction unit (200) according to the present invention may include a first electrode (60A), a second electrode (60B), a reactant (100) filled in the reactor, and a stirrer (75).

[0144] The first electrode and the second electrode (60A, 60B) according to the present invention are electrodes capable of electrolyzing hydrochloric acid and can be electrically connected to each other. Here, being electrically connected may mean a series connection, a parallel connection, or a mixed connection of a series connection and a parallel connection. Specifically, the first and second electrodes (60A, 60B) can be immersed in the reactant (100), and more specifically, a portion of the first and second electrodes (60A, 60B) can be immersed in the reactant (100) and come into direct contact with the reactant (100).

[0145] In some examples, when the reactant (100) includes hydrochloric acid, the first electrode (60A) and the second electrode (60B) can electrolyze the hydrochloric acid. In this case, the first electrode (60A) may be a cathode where a reduction reaction in which hydrogen ions gain electrons occurs to generate hydrogen gas, and the second electrode (60B) may be an anode where an oxidation reaction in which chloride ions lose electrons occurs to generate chlorine gas. At this time, at least one of the first and second electrodes (60A, 60B) may be in direct contact with the hydrochloric acid, and specifically, the first and second electrodes (60A, 60B) may be in direct contact with the hydrochloric acid. The reason why at least one of the first and second electrodes (60B) may be in direct contact with the hydrochloric acid may be because a separation membrane is not provided in the electrolysis reaction unit (200) described above. According to some embodiments of the present invention, by having at least one of the first and second electrodes (60A, 60B) in direct contact with the hydrochloric acid, the manufacturing process and process management can be facilitated, and the cost of replacing the separator due to breakage of the separator can be reduced.

[0146] In some examples, the first electrode (60A) may be a cathode and may include stainless steel, titanium, aluminum, iron, copper, Hastelloy, or an alloy or composite material including at least one of these.

[0147] In some examples, the second electrode (60B) may be an anode, and may be one selected from the group consisting of titanium, Hastelloy, platinum, stainless steel, gold, silver, iridium, iridium coated metal, ruthenium, chromium, nickel, manganese, iron, rubidium or oxides thereof, graphite, and carbon lead; two or more alloys; or two or more physical mixtures.

[0148] In some examples, when the reactant (100) includes a hydrazo compound, the first and second electrodes (60A, 60B) can oxidize the hydrazo compound with chlorine gas generated by the electrolysis to generate an azo compound. At this time, at least one of the first and second electrodes (60A, 60B) can be in direct contact with the hydrazo compound, and specifically, the first and second electrodes (60A, 60B) can be in direct contact with the hydrazo compound. The reason why at least one of the first and second electrodes (60B) can be in direct contact with the hydrazo compound may be because a separator is not provided in the electrolysis reaction unit (200) described above. According to some embodiments of the present invention, since at least one of the first and second electrodes (60B) is in direct contact with the hydrazo compound, the manufacturing process and process management can be facilitated, and the cost of replacing the separator due to breakage of the separator can be reduced.

[0149] In some examples, the reactant (100) may include a solvent or dispersion medium in a slurry or solution state. For example, the solvent or dispersion medium may include at least one of water, alcohol, and an organic solvent.

[0150] In some examples, electrical energy is applied to the electrolysis reaction unit (200) for the electrolysis reaction, wherein the power applied to the electrolysis reaction unit (200) may be about 1 W to 10 W per 1 g of the azo compound. In this case, the electrolysis reaction may take, for example, about 4 to 6 hours to be completed. As a specific example, when a current of about 10 A is applied per 100 g of the hydrazo compound, it may take about 4 to 6 hours.

[0151] In some examples, the voltage applied to the electrolysis reaction unit (200) may be 1 V or more, 2 V or more, 3 V or more, 4 V or more, 5 V or more, 6 V or more, 7 V or more, 8 V or more, 9 V or more, 10 V or more, 11 V or more, 12 V or more, or 13 V or more; 2 V or less, 3 V or less, 4 V or less, 5 V or less, 6 V or less, 7 V or less, 8 V or less, 9 V or less, 10 V or less, 11 V or less, 12 V or less, or 13 V or less; or any one or more of the plurality of lower limits and any one or less of the plurality of upper limits. Specifically, the voltage applied to the electrolysis reaction unit (200) may be about 1 V to 13 V, and specifically, 2 V to 12 V. Because these power and voltage ranges are relatively low, power consumption can be reduced and manufacturing costs can be reduced.

[0152] In some examples, the reaction temperature in the electrolysis reaction unit (200) may be 10°C or higher, 20°C or higher, 30°C or higher, 40°C or higher, 45°C or higher, 50°C or higher, 60°C or higher, or 70°C or higher; 20°C or lower, 30°C or lower, 40°C or lower, 50°C or lower, 60°C or lower, 70°C or lower, or 80°C or lower; or any one or more of the plurality of lower limits and any one or less of the plurality of upper limits. In some examples, the reaction temperature in the electrolysis reaction unit (200) may be performed at 10 to 80°C, specifically, 10 to 45°C. When the reaction temperature satisfies the numerical range, the azo compound is not decomposed by heat, so the yield of the azo compound is sufficiently high, and at the same time, the required power per weight of the azo compound can be adjusted to an appropriate level.

[0153] The stirrer (75) according to the present invention can promote the electrolysis reaction of the hydrochloric acid and the production reaction of the azo compound. In particular, when the reactant (100) is in a slurry state rather than a solution state, the stirrer (75) is provided in the electrolysis reaction unit (200), so that both reactions can proceed more smoothly. However, the stirrer (75) illustrated in FIG. 4 is an exemplary form, and is not particularly limited and may be a wing-type stirrer or a magnetic bar type of various forms. The stirring speed (rpm) of the stirrer (75) can be appropriately modified depending on the type of stirrer.

[0154] According to another embodiment of the present invention, unlike the embodiment shown in FIG. 4, the stirrer (75) may be omitted.

[0155] Figure 5 is a hydrogen gas purification system according to another embodiment of the present invention.

[0156] Referring to FIG. 5, the electrolysis reaction unit (200) according to the present invention may include a reaction tank (25) and an electrolytic tank (55) connected to the reaction tank (25). Specifically, the reaction tank (25) and the electrolytic tank (55) may be separated from each other. Here, the separation of the reaction tank (25) and the electrolytic tank (55) may mean that the electrolysis reaction of hydrochloric acid occurs in a physically separated space. Specifically, the electrolytic tank (55) may perform an electrolysis reaction of first hydrochloric acid to generate hydrogen gas, first chlorine gas, second chlorine gas, and a sub-gas, and may primarily react the second chlorine gas with a hydrazo compound to generate an azo compound. Specifically, the reaction tank (25) may react the first chlorine gas supplied from the electrolytic tank (55) with the hydrazo compound to generate an azo compound.

[0157] In another embodiment of the present invention, the hydrazo compound may include a first hydrazo compound and a second hydrazo compound different from the first hydrazo compound. Specifically, the first hydrazo compound may be used as a reactant in the synthesis process of the azo compound in the electrolytic cell (55), and the second hydrazo compound is a hydrazo compound that is not used in the synthesis process of the azo compound, and may be transferred from the electrolytic cell (55) to the reaction cell (25) together with unreacted chlorine gas to allow further reaction to proceed.

[0158] According to some embodiments of the present invention, since the reaction tank (25) and the electrolytic tank (55) are configured to be separated from each other, the electrolytic tank can include two or more pairs of electrodes (anode, cathode), thereby further increasing the yield of the azo compound and the recovery rate and purity of hydrogen gas.

[0159] Figure 6 is an electrolysis reaction unit according to another embodiment of the present invention. Parts that are repeated from the above description are briefly described or omitted.

[0160] Referring to FIG. 6, in another embodiment of the present invention, the electrolysis reaction unit (200) may be such that, unlike the embodiment illustrated in FIG. 4, the electrolytic cell (55) and the reaction cell (25) are separated from each other.

[0161] As described above, the reaction tank (25) according to the present invention includes a first electrode (60A) and a second electrode (60B) facing the first electrode (60A), and the first and second electrodes (60A, 60B) can be in direct contact with the hydrazo compound. The reason why at least one of the first and second electrodes (60A, 60B) can be in direct contact with the hydrazo compound may be because a separation membrane is not provided within the reaction tank (25).

[0162] An electrolytic cell (55) according to the present invention includes a third electrode (65A) and a fourth electrode (65B) facing the third electrode (65A), and the third electrode (65A) and the fourth electrode (65B) can directly contact at least one of a hydrochloric acid solution and a hydrazo compound, and specifically, can contact both the hydrochloric acid solution and the hydrazo compound. The reason why the third and fourth electrodes (65A, 65B) can directly contact the hydrochloric acid solution and the hydrazo compound may be because a separator is not provided in the electrolytic cell (55) described above. According to some embodiments of the present invention, since the third and fourth electrodes (65A, 65B) directly contact the hydrochloric acid solution and the hydrazo compound, the manufacturing process and process management become easier, and the cost of replacing the separator due to breakage of the separator can be reduced. In some examples, the third electrode (65A) and the fourth electrode (65B) may be a plurality of electrodes arranged alternately.

[0163] In some examples, the third electrode (65A) and the fourth electrode (65B) may be made of the same or different materials as the first electrode (60A) and the second electrode (60B), respectively.

[0164] The electrolysis reaction unit (200) according to the present invention may further include first and second connecting parts (35a, 35b), a discharge part (6), a dehydration part (7), and an input part (3A, 3B).

[0165] The first connecting portion (35a) according to the present invention can provide a path for transporting hydrochloric acid, a by-product generated in the reaction tank (25), to the electrolytic tank (55). Specifically, the first connecting portion (35a) can provide power to transport the hydrochloric acid generated in the reaction tank (25) to the electrolytic tank (55) and to transport the first chlorine gas generated in the electrolytic tank (55) to the reaction tank (25) by having a pump (45).

[0166] The second connection unit (35b) according to the present invention can provide a path for moving the first chlorine gas generated in the electrolytic cell (55) to the reaction tank (25). In some examples, a gas treatment unit (85) can be provided in the second connection unit (35b). At this time, the gas treatment unit (85) can capture various types of gases such as ammonia gas, nitrogen gas, hydrogen gas, chlorine gas, or bromine gas generated in the process of performing the method for producing an azo compound. In some examples, the gases captured through the gas treatment unit (85) can be transferred to a scrubber (300) described below and undergo the hydrogen gas purification process described above.

[0167] The discharge unit (6) according to the present invention can contribute to the discharge of the azo compound being produced. For example, the discharge unit (6) can be connected to one end of the reaction tank (25), and specifically, can be directly connected.

[0168] The dehydration unit (7) according to the present invention can remove water and the like obtained during the process of producing an azo compound. For example, the dehydration unit (7) may be a centrifuge or a depressurizing filter. Specifically, the dehydration unit (7) may be directly connected to the discharge unit (6).

[0169] The input unit (3A, 3B) according to the present invention may include a first input unit (3A) for inputting a hydrazo compound in the form of a slurry, and a second input unit (3B) for inputting a hydrochloric acid solution. Specifically, the hydrochloric acid solution inputted through the second input unit (3B) may be electrolyzed to produce chlorine gas, and by oxidizing the hydrazo compound with the generated chlorine gas, an azo compound and hydrochloric acid may be obtained. Here, the obtained hydrochloric acid may be transferred to the electrolytic cell (55) through the first connecting unit (35a) and used as a reactant in the electrolysis reaction of hydrochloric acid.

[0170] According to another embodiment of the present invention, unlike the embodiment shown in FIG. 6, the stirrer (75) may be omitted.

[0171] Gas-liquid separator (250)

[0172] The gas-liquid separator (250) according to the present invention can induce a purification process of removing the second chlorine gas and the sub-gas by transferring the mixed gas including the hydrogen gas, the second chlorine gas, and the sub-gas generated when electrolyzing the first hydrochloric acid to a scrubber (300) to be described later. In some examples, the gas-liquid separator (250) can separate the unnecessary liquid generated during the electrolysis process of the first hydrochloric acid from the mixed gas in order to selectively input the mixed gas into the purification process. If necessary, the unnecessary liquid can be discharged by various discharge means in the relevant technical field.

[0173] Specifically, the above-described gas-liquid separator (250) can be connected to the electrolysis reaction unit (200) and the scrubber (300) described later, and more specifically, can be directly connected to them.

[0174] Scrubber (300)

[0175] The scrubber (300) according to the present invention may be a device that removes at least one of chlorine gas, hydrogen chloride (HCl(g)), and water (H2O(g)) from the mixed gas. Specifically, the scrubber (300) may be connected to the gas-liquid separator (250), and more specifically, may be directly connected to the gas-liquid separator (250).

[0176] Figure 7 illustrates a hydrogen gas purification system according to another embodiment of the present invention. Parts described above and repeated descriptions are briefly described or omitted.

[0177] Referring to FIG. 7, in some embodiments of the present invention, the scrubber (300) may include a first scrubber (301) for removing first chlorine gas and hydrogen chloride (HCl(g)) and a second scrubber (302) for removing second chlorine gas and water (H2O(g)). Specifically, the first scrubber (301) may be directly connected to the second scrubber (302). According to some embodiments of the present invention, by combining the first and second scrubbers (301, 302), the chlorine gas removal efficiency may be further increased, and the recovery rate and purity of hydrogen gas may be further increased.

[0178] In some examples, the first scrubber (301) may be the wet scrubber, and the second scrubber (302) may be the cooling scrubber.

[0179] Hydrogen gas collector (400)

[0180] The hydrogen gas collector (400) according to the present invention may be a device that stores hydrogen gas among the gases discharged from the scrubber (300). Specifically, the hydrogen gas collector (400) may be connected to the scrubber (300), and more specifically, may be directly connected.

[0181] Gas adsorption device (500)

[0182] The gas adsorption device (500) according to the present invention can remove the fourth gas. Specifically, the fourth gas may include nitrogen gas, oxygen gas, and carbon dioxide. In some examples, the gas adsorption device (500) may be a device capable of implementing the pressure-cycling adsorption method described above.

[0183] In some examples, the gas adsorption device (500) can effectively remove a fourth gas including nitrogen gas, oxygen gas, and carbon dioxide by having an adsorption tower filled with the above-described adsorbent. Accordingly, the recovery rate and purity of hydrogen gas can be further increased.

[0184] 3. Hydrogen gas regeneration method and hydrogen gas regeneration system

[0185] According to another aspect of the present invention, a method for regenerating hydrogen gas is provided, comprising a method for purifying hydrogen gas according to some embodiments.

[0186] The method for regenerating hydrogen gas according to the present invention is not particularly limited, and may refer to a method for utilizing purified and recovered hydrogen gas in various ways according to the purpose. In some examples, the purified hydrogen gas can be used in various fields such as crude oil refining, steel manufacturing, foundry manufacturing, manufacturing processes for semiconductors, computers, mobile phones, etc., optical fiber manufacturing processes, glass manufacturing processes, hydrogen fuel cell vehicles, rocket fuel, ammonia, hydrochloric acid, methanol, etc., synthesis reactions, hydrogen peroxide production reaction raw materials, metal heat treatment processes, polysilicon manufacturing processes, nuclear power plant raw materials, solar power generators, petroleum manufacturing processes, manufacturing processes for platinum, gold, quartz, etc., and fat addition during food manufacturing. Specifically, the purified hydrogen gas can be regenerated by a method for reacting with oxygen gas to produce hydrogen peroxide. Here, hydrogen peroxide is widely used in bleaching agents, oxidizing agents, derivative manufacturing, etc., and therefore, when the method for regenerating hydrogen gas according to the present invention is used, the effect of producing azo compounds and hydrogen peroxide with high production efficiency in various fields of application can be realized.

[0187] In some examples, the weight ratio of the azo compound and hydrogen peroxide produced above (azo compound:hydrogen peroxide) may be 1000:200 or more and 1000:400 or less.

[0188] According to some embodiments of the present invention, the hydrogen peroxide generated from the purified hydrogen gas can react with a hydrazodicarbonamide to generate an azo compound. For example, the hydrogen peroxide can react with hydrazodicarbonamide (HDCA) as an oxidizing agent to generate azodicarbonamide (ADCA).

[0189] According to some embodiments of the present invention, the azo compound produced by reacting the hydrogen peroxide generated from the purified hydrogen gas with the hydrazo compound has a thermal decomposition temperature (Temperature of Decomposition, T) that is 3°C or higher, specifically 5°C or higher, and more specifically 5°C to 15°C higher than the conventional azo compound produced by reacting the hydrazo compound with chlorine gas, because it is synthesized using hydrogen peroxide. d ) can have. For example, the thermal decomposition temperature can be analyzed using TGA (Thermo Gravimetric Analysis). Therefore, it has the advantage of diversifying the application fields by increasing the types of synthetic resins that can be mixed during the manufacture of foam. For example, the azo compound produced by reacting the hydrogen peroxide generated from the purified hydrogen gas with the hydrazo compound can be mixed with polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), rubber, ethylene-vinyl acetate copolymer (EVA), polystyrene (PS), polyurethane (PU), transparent silicone, etc.

[0190] According to another aspect of the present invention, a hydrogen gas regeneration system including a hydrogen gas purification system of several embodiments is provided.

[0191] Figure 8 is a flowchart illustrating a hydrogen gas regeneration system according to one embodiment of the present invention. Figure 9 is a flowchart illustrating a hydrogen gas regeneration system according to another embodiment of the present invention. Parts that have been described above and are repeated are briefly described or omitted.

[0192] Referring to FIGS. 8 and 9, the hydrogen gas regeneration system (2000) according to the present invention may include the above-described hydrogen gas purification system (1000) and a hydrogen peroxide generation device (600) connected to the hydrogen gas purification system (1000).

[0193] The hydrogen peroxide generator (600) according to the present invention may be, for example, a device that generates hydrogen peroxide by reacting hydrogen gas purified through the hydrogen gas purification system (1000) with oxygen gas introduced from the outside. In some examples, the hydrogen peroxide generator (600) is not particularly limited and may be a device that synthesizes hydrogen peroxide by directly reacting oxygen gas and hydrogen gas in the presence of a catalyst. Specifically, the catalyst is not particularly limited and may be various catalysts such as a Pd catalyst and a Pt-Au alloy catalyst.

[0194] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, this is merely an example, and the scope of the present invention is not limited by the following contents.

[0195] <Examples 1 to 12: Chlorine removal using a scrubber absorbent containing a monovalent base or a divalent base>

[0196] A 100 L reaction tank in an electrolysis reaction unit was filled with 12 wt% hydrochloric acid, 20 wt% HDCA (hydrazodcarbonamide), and water to prepare a total of 70 kg of reaction solution.

[0197] Then, the reaction solution was moved from the reactor to the electrolytic cell using a pump, and direct current of 300 A was applied to each of the eight cells to cause an electrolysis reaction.

[0198] As the electrolysis reaction progresses, an oxidation reaction occurs in HDCA and gas is generated. The gas generated at this time is 80 m 3The air was circulated in the tank of the first scrubber at a rate of / min, and an alkaline aqueous solution was added to the reaction liquid in the tank of the first scrubber at the concentrations shown in Table 1 below.

[0199] Afterwards, the concentration of residual chlorine gas in the gas discharged from the first scrubber was measured using a chlorine gas detector (GASTEC of Chosun Measuring Instrument Co., Ltd.), and the results are shown in Table 1 below.

[0200] <Comparative examples and examples 13 to 15: Chlorine removal using a scrubber absorbent containing or not containing a trivalent base>

[0201] The concentration of residual chlorine gas discharged from the first scrubber was measured in the same manner as in Example 1, except that no base reagent was used instead of NaOH (comparative example) or a trivalent base reagent (Examples 13 to 15) was added to the reaction solution instead of NaOH.

[0202] Classification Absorbent base Base content (wt%) Residual chlorine concentration after passing through the scrubber (ppm) Example 1 NaOH 20 10 Example 2 NaOH 10 70 Example 3 NaOH 5 12 1 Example 4 KOH 20 10 Example 5 KOH 10 65 Example 6 KOH 5 11 5 Example 7 Mg(OH) 2 20 30 Example 8 Mg(OH) 2 10 10 8 Example 9 Mg(OH) 2 5 13 3 Example 10 Ca(OH) 2 20 29 Example 11 Ca(OH) 2 10 10 1 Example 12 Ca(OH) 2 5 12 7 Comparative example-- 20 0 Example 13 Al(OH) 3 20 18 5 Example 14 Cr(OH) 3 20 18 8 Example 15 Fe(OH) 3 20 19 9

[0203] Referring to Table 1 above, it was confirmed that the chlorine removal effect was better when a monovalent base or divalent base was used as the absorbent when removing chlorine using a scrubber.

[0204] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

[0205] [Explanation of symbols]

[0206] 3A: 1st input 3B: 2nd input

[0207] 6: Discharge section 7: Dehydration section

[0208] 25: Reactor 35a: First connection

[0209] 35b: Second connection 45: Pump

[0210] 55: Electrolytic cell 60A: First electrode

[0211] 60B: Second electrode 65A: Third electrode

[0212] 65B: 4th electrode 75: Stirrer

[0213] 85: Gas treatment unit 100: Reactant

[0214] 200: Electrolysis reaction unit 250: Gas-liquid separator

[0215] 300: Scrubber 301: First scrubber

[0216] 302: Second scrubber 400: Hydrogen gas collector

[0217] 500: Gas adsorption device 1000: Hydrogen gas purification system

[0218] 600: Hydrogen peroxide generator 2000: Hydrogen gas regeneration system

Claims

1. Purifying a mixed gas containing chlorine gas and hydrogen gas generated by an electrolytic method; Including; Method for purifying hydrogen gas.

2. In paragraph 1, Electrolyzing the first hydrochloric acid to produce hydrogen gas, first chlorine gas, and second chlorine gas; and Further comprising obtaining second hydrochloric acid by reaction of the first chlorine gas and a hydrazo compound; The above chlorine gas comprises the second chlorine gas, Method for purifying hydrogen gas.

3. In paragraph 2, The above second hydrochloric acid is circulated and included in the above first hydrochloric acid. Method for purifying hydrogen gas.

4. In paragraph 3, One cycle is performed repeatedly, which consists of electrolyzing the first hydrochloric acid to produce hydrogen gas, first chlorine gas, and second chlorine gas, and obtaining the second hydrochloric acid by reacting the first chlorine gas with a hydrazo compound. Method for purifying hydrogen gas.

5. In paragraph 1, The content of chlorine gas based on the total volume of the above mixed gas is 200 ppm or less. Method for purifying hydrogen gas.

6. In paragraph 1, The volume ratio of the above chlorine gas and the above hydrogen gas is 1:1500 or more and 1:2000 or less, Method for purifying hydrogen gas.

7. In paragraph 1, The above mixed gas is, It further comprises at least one sub-gas selected from nitrogen gas, oxygen gas, carbon dioxide, hydrogen chloride (HCl(g)), and water (H2O(g)). The content of the above sub-gas is 30% (v / v) or less based on the total volume of the above mixed gas. Method for purifying hydrogen gas.

8. In paragraph 1, Purifying the above mixed gas is as follows: Including: injecting the above mixed gas into a scrubber to remove the first gas and obtain the second gas; The first gas comprises chlorine gas, Method for purifying hydrogen gas.

9. In paragraph 8, The above scrubber, comprising a first scrubber and a second scrubber connected to the first scrubber; Purifying the above mixed gas is as follows: Removing the first gas with an absorbent in the first scrubber; Comprising cooling the second gas in the second scrubber to obtain a liquid and a third gas, Method for purifying hydrogen gas.

10. In paragraph 9, The above absorbent liquid contains a basic aqueous solution having a pH of 10 or higher. Method for purifying hydrogen gas.

11. In paragraph 8, The content of chlorine gas in the second gas is less than 20 ppm, Method for purifying hydrogen gas.

12. In paragraph 9, Purifying the above mixed gas is as follows: Further comprising removing a fourth gas from the third gas; The above fourth gas is, Containing at least one selected from nitrogen gas, oxygen gas and carbon dioxide, Method for purifying hydrogen gas.

13. In paragraph 12, The above fourth gas is removed by an adsorption method. Method for purifying hydrogen gas.

14. In paragraph 13, The above adsorption method includes a pressure cycling adsorption method. Method for purifying hydrogen gas.

15. Electrolyze the first hydrochloric acid to produce hydrogen gas, first chlorine gas, second chlorine gas, and a sub-gas; A second hydrochloric acid is obtained by the reaction of the first chlorine gas and a hydrazo compound; A mixed gas including the second chlorine gas, the hydrogen gas, and the sub gas is introduced into a first scrubber to remove the first gas and obtain a second gas; The second gas is injected into a second scrubber and cooled to obtain a liquefied liquid and a third gas; Injecting the above third gas into a hydrogen gas collector; and Including: removing the fourth gas by injecting the third gas discharged from the hydrogen gas collector into a gas absorption device; The above sub-gas contains at least one selected from nitrogen gas, oxygen gas, carbon dioxide, hydrogen chloride (HCl(g)), and water (H2O(g)). The fourth gas includes nitrogen gas, oxygen gas, and carbon dioxide, The above second hydrochloric acid is circulated and included in the above first hydrochloric acid. Method for purifying hydrogen gas.

16. Electrolysis reaction unit; A gas-liquid separator connected to the above electrolysis reaction unit; A scrubber connected to the above gas-liquid separator; A hydrogen gas collector connected to the above scrubber; and A gas absorption device connected to the above hydrogen gas collector; including; Hydrogen gas purification system.

17. In paragraph 16, The above electrolysis reaction unit is, Including a reactor and an electrolytic tank, The above reaction tank and the above electrolytic tank are not separated from each other or are separated, Hydrogen gas purification system.

18. In paragraph 17, A hydrazo compound is contained inside the above reactor, A hydrochloric acid solution is contained inside the above electrolytic cell, Hydrogen gas purification system.

19. In Article 18, The above reaction tank is, comprising a first electrode and a second electrode, The first electrode and the second electrode are in direct contact with the hydrazo compound. Hydrogen gas purification system.

20. In paragraph 18, The above electrolytic cell, Including a third electrode and a fourth electrode, The third electrode and the fourth electrode are in direct contact with the hydrochloric acid solution. Hydrogen gas purification system.

21. In paragraph 16, The above scrubber, A first scrubber for removing first chlorine gas and hydrogen chloride (HCl(g)), and Including a second scrubber for removing second chlorine gas and water (H2O(g)). Hydrogen gas purification system.

22. A method for regenerating hydrogen gas, comprising a method for purifying hydrogen gas according to any one of claims 1 to 15.

23. In paragraph 22, The above hydrogen gas regeneration method is, Comprising reacting the purified hydrogen gas and oxygen gas to produce hydrogen peroxide. Method for regenerating hydrogen gas.

24. A hydrogen gas purification system according to any one of claims 16 to 21; including; Hydrogen gas regeneration system.

25. In paragraph 24, Further comprising a hydrogen peroxide generating device connected to the above hydrogen gas purification system; Hydrogen gas regeneration system.

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