Method for reducing material consumption in chlorine preparation through hydrogen chloride oxidation

Abstract

The invention relates to a method for reducing material consumption in preparation of chlorine by oxidizing hydrogen chloride, which comprises the following steps: mixing hydrogen chloride containing doped components, oxygen and recycle gas, then carrying out catalytic oxidation reaction, and sequentially carrying out impurity removal treatment and doped component removal on the obtained reaction gas to obtain recycle gas and chlorine, recycling part of the obtained recycle gas in the mixture, and absorbing part of the recycle gas as tail gas through absorption liquid; according to the method, the oxygen feeding amount and the absorption liquid consumption amount are adjusted in real time by monitoring the content of doped components in hydrogen chloride and the content of components in circulating gas. The pure oxygen consumption and the absorption liquid consumption are reduced while the high conversion rate is maintained only by establishing the logic relation of key parameters, equipment modification or reaction accelerant introduction or catalyst replacement is not needed, the original process is not modified, and the method has the advantage of being simple in process.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen chloride oxidation reaction, and in particular to a method for reducing material consumption in hydrogen chloride oxidation to prepare chlorine. Background Art

[0002] In the process of producing isocyanates by the phosgene method, most of the chlorine atoms are discharged in the form of hydrogen chloride after carbonyl substitution. The treatment of a large amount of by-product hydrogen chloride requires relatively high costs, which directly restricts the development of the isocyanate industry.

[0003] At present, the main methods for treating by-product hydrogen chloride include: using absorption method to produce hydrochloric acid, acid-base neutralization method, manufacturing vinyl chloride products, using Deacon method to produce chlorine gas through hydrogen chloride oxidation, etc. Among them, the Deacon method hydrogen chloride oxidation process can realize the recycling of chlorine resources, which is in line with the economic development model of resource recycling and is crucial to promoting the sustainable development of chlorine-related industries and protecting the environment; at the same time, the Deacon method hydrogen chloride oxidation process has many advantages such as no other side reactions, simple process flow, and high efficiency.

[0004] In the conventional process of catalytic oxidation of hydrogen chloride using oxygen, different types of catalysts are usually used, such as ruthenium catalysts, chromium catalysts or copper catalysts. For example, CN101125297A discloses an oxychlorination catalyst and its application, the catalyst comprising salts and / or oxides of copper, phosphorus, alkali metals, rare earth metals and an inert carrier, wherein the content of copper element accounts for 2-15wt% of the weight of the catalyst, the content of phosphorus element accounts for 1-10wt%, the content of alkali metal element accounts for 1-10wt%, the content of rare earth metal element accounts for 0-5wt%, and the rest is an inert carrier; CN104549360A discloses a catalyst used in the process of catalytic oxidation of hydrogen chloride to produce chlorine, specifically a catalyst containing ruthenium, copper element, alkali metal element and rare earth metal element prepared by a double impregnation method, the catalyst having a core-shell structure. Among them, copper-based catalysts have relatively low manufacturing costs, and the preparation of chlorine by catalytic oxidation of hydrogen chloride is the most promising green chemical process for resource recycling.

[0005] At present, the composition of raw material hydrogen chloride is usually fixed in the process of hydrogen chloride oxidation to produce chlorine, and the oxygen feed amount and tail gas emission are fixed by the chlorine-oxygen ratio. For example, CN 108928803A discloses a method for producing chlorine by hydrogen chloride oxidation, in which hydrogen chloride and oxygen pass through a hydrogen chloride catalytic oxidation unit, a deoxygenation unit, a hydrogen chloride removal unit and a drying unit in sequence. However, in the process of hydrogen chloride oxidation to produce chlorine, on the one hand, the reaction conversion rate may be reduced, the chlorine yield may be reduced, and on the other hand, pure oxygen consumption and tail gas treatment agent may be wasted, thereby increasing the production cost of hydrogen chloride oxidation to prepare chlorine.

[0006] Therefore, in view of the shortcomings of the prior art, it is necessary to provide a method for producing chlorine gas by oxidizing hydrogen chloride with high conversion rate and reducing material consumption. Summary of the invention

[0007] The object of the present invention is to provide a method for reducing material consumption in the production of chlorine by hydrogen chloride oxidation, which can maintain a high conversion rate in the hydrogen chloride oxidation reaction process while reducing pure oxygen consumption and waste of tail gas absorption liquid.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for reducing material consumption in the process of preparing chlorine by oxidation of hydrogen chloride, the method comprising the following steps:

[0010] The hydrogen chloride containing doping components, oxygen and circulating gas are mixed and then subjected to catalytic oxidation reaction, and the obtained reaction gas is subjected to impurity removal treatment and doping component removal in sequence to obtain circulating gas and chlorine; part of the obtained circulating gas is recycled in the mixing, and part of it is absorbed by an absorption liquid as tail gas;

[0011] In the method, the oxygen feed amount and the absorption liquid consumption are adjusted in real time by monitoring the content of the doping component in the hydrogen chloride and the component content of the circulating gas.

[0012] The method for reducing material consumption in preparing chlorine by hydrogen chloride oxidation provided by the present invention can adjust the molar ratio of hydrogen chloride to oxygen and the reaction temperature by monitoring the content of doping components in hydrogen chloride, maintain a high conversion rate, and further optimize the oxygen feed amount in real time, thereby reducing the oxygen unit consumption; by monitoring the component content of the circulating gas, the optimal circulating gas volume can be adjusted in real time, and the consumption of the absorption liquid can be controlled in combination with the tail gas emission. The method only maintains a high conversion rate while reducing the consumption of pure oxygen and the absorption liquid by establishing a logical relationship between key parameters, without the need to modify the equipment or introduce a reaction promoter or replace the catalyst, and without modifying the original process, and has the characteristics of simple process.

[0013] The catalytic oxidation reaction of the present invention will produce hydrochloric acid as a by-product.

[0014] The doping components in the hydrogen chloride include carbon monoxide, carbon dioxide and nitrogen, and the mass fraction of the doping components is ≤5%, for example, it can be 5%, 4%, 3%, 2% or 1%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] Preferably, based on the total mass fraction of 100%, the circulating gas includes: 40-60% oxygen, ≤35% nitrogen, ≤40% carbon dioxide, and 5-10% chlorine;

[0016] The component content of the tail gas is the same as the component content of the circulating gas.

[0017] The mass fraction of oxygen in the circulating gas is 40-60%, for example, 40%, 45%, 50%, 52%, 56% or 60%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] The mass fraction of nitrogen in the circulating gas is ≤35%, for example, it can be 35%, 33%, 29%, 10% or 5%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0019] The mass fraction of carbon dioxide in the circulating gas is ≤40%, for example, it can be 40%, 15%, 11%, 10% or 5%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] The mass fraction of chlorine in the circulating gas is 5-10%, for example, 5%, 6%, 7%, 8% or 10%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] Preferably, the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing the doping component to the total amount of oxygen after mixing is (1-4):1, for example, it can be 1:1, 1.5:1, 1.8:1, 2:1, 3:1 or 4:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably (1.5-2):1.

[0022] Preferably, the feed temperature after mixing is 20-200°C, for example, 20°C, 40°C, 80°C, 100°C, 150°C or 200°C, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable, preferably 40-100°C;

[0023] The temperature of the catalytic oxidation reaction is 300-500°C and the pressure is 100-600kPa(G);

[0024] The catalyst for catalyzing the oxidation reaction includes a ruthenium-based catalyst and / or a copper-based catalyst, preferably a copper-based catalyst.

[0025] The temperature of the catalytic oxidation reaction is 300-500°C, for example, 300°C, 330°C, 400°C, 450°C or 500°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 330-450°C.

[0026] The pressure of the catalytic oxidation reaction is 100-600 kPa (G), for example, it can be 100 kPa (G), 200 kPa (G), 300 kPa (G), 500 kPa (G) or 600 kPa (G), but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 200-500 kPa (G).

[0027] Preferably, the ruthenium-based catalyst is a supported ruthenium catalyst, comprising an active component and a carrier, wherein the active component comprises ruthenium dioxide, and the carrier comprises at least one of aluminum oxide, titanium oxide, zirconium oxide or cobalt oxide.

[0028] Preferably, based on the total mass percentage as 100wt%, the active component in the supported ruthenium catalyst is 0.1-10wt%, for example, it can be 0.1wt%, 5wt% or 10wt%, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, and the rest are carriers and additives.

[0029] Preferably, the copper-based catalyst is a supported copper catalyst, comprising an active component and a carrier, wherein the active component comprises cupric chloride, and the carrier comprises at least one of aluminum oxide, iron oxide or silicon dioxide.

[0030] Preferably, based on the total mass percentage as 100wt%, the active component in the supported copper catalyst is 1-20wt%, for example, it can be 1wt%, 10wt% or 20wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, and the rest are carriers and additives.

[0031] Preferably, the impurity removal treatment method includes any one of condensation, adsorption, distillation or membrane separation or a combination of at least two of them. Typical but non-limiting combinations include a combination of condensation and adsorption, a combination of distillation and membrane separation, or a combination of condensation, adsorption, distillation and membrane separation.

[0032] The method of removing the doping components includes any one of distillation, adsorption or membrane separation or a combination of at least two of them. Typical but non-limiting combinations include a combination of distillation and adsorption, a combination of adsorption and membrane separation, or a combination of distillation, adsorption and membrane separation, preferably distillation.

[0033] Preferably, the absorption liquid comprises sodium hydroxide solution and / or potassium hydroxide solution, preferably sodium hydroxide solution.

[0034] Preferably, the calculation formula for the oxygen feed amount is as follows:

[0035] V 1 =V 2 ×(1-a) / bV 3 ×c;

[0036] Where: V 1 Indicates the oxygen feed rate in Nm 3 / h; V 2 Indicates the amount of hydrogen chloride feed containing doping components, in Nm 3 / h; a represents the mass fraction of the doping component in hydrogen chloride, in %; b represents the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing the doping component to the total amount of oxygen after mixing; V 3 Indicates the circulating gas volume in Nm 3 / h; c represents the mass fraction of oxygen in the circulating gas, in %.

[0037] In the calculation formula, the oxygen feed amount V 1 , the amount of hydrogen chloride feed containing doping components V 2 And the circulating gas volume V 3 The mass fraction a of the doping component in the hydrogen chloride and the mass fraction c of the oxygen in the circulating gas are measured by an online gas chromatograph.

[0038] Preferably, the calculation formula for the absorption liquid consumption is as follows:

[0039] m=k×V 4 ×(e+f);

[0040] Where: m represents the absorption liquid consumption, in g / h; k represents the absorption liquid coefficient, when the absorption liquid is sodium hydroxide solution, k = 3.571; when the absorption liquid is potassium hydroxide solution, k = 5; V 4 Indicates exhaust gas emissions in Nm 3 / h; e represents the mass fraction of chlorine in the tail gas, in %; f represents the mass fraction of carbon dioxide in the tail gas, in %.

[0041] The absorption liquid coefficient k is calculated by the theoretical consumption and surplus coefficient of chlorine and carbon dioxide corresponding to different absorption liquids.

[0042] Preferably, the circulating gas volume V 3 and exhaust emissions V 4 It is the component of the circulating gas obtained after the reaction gas is treated with impurities and doped components. The total volume fraction of the circulating gas is 100%. The circulating gas volume V 3 30-80%, preferably 40-70%, the remainder is the exhaust gas emission V 4 .

[0043] The circulating gas volume V 3The volume fraction is 30-80%, for example, 30%, 40%, 50%, 70% or 80%, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 40-70%.

[0044] In the calculation formula, the exhaust emission V 4 The mass fraction e of chlorine in the tail gas and the mass fraction f of carbon dioxide in the tail gas are measured by an online gas chromatograph.

[0045] Preferably, as a preferred technical solution of the method described in the present invention, the method comprises the following steps:

[0046] The hydrogen chloride containing doping components, oxygen and circulating gas are mixed, and the feed temperature after mixing is 20-200°C; then a catalytic oxidation reaction is carried out at 300-500°C and 100-600kPa(G), and the obtained reaction gas is subjected to impurity removal treatment and doping component removal in turn to obtain circulating gas and chlorine; part of the obtained circulating gas is recycled in the mixing, and part of it is absorbed by an absorption liquid as tail gas;

[0047] The doping components in the hydrogen chloride include carbon monoxide, carbon dioxide and nitrogen, and the mass fraction of the doping components is ≤5%; based on the total mass fraction of 100%, the circulating gas includes: 40-60% oxygen, ≤35% nitrogen, ≤40% carbon dioxide, and 5-10% chlorine; the component content of the tail gas is the same as the component content of the circulating gas; the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing the doping components to the total amount of oxygen after mixing is (1-4):1;

[0048] In the method, the oxygen feed amount and the absorption liquid consumption are adjusted in real time by monitoring the content of the doping component in the hydrogen chloride and the component content of the circulating gas;

[0049] The calculation formula of the oxygen feed amount is as follows:

[0050] V 1 =V 2 ×(1-a) / bV 3 ×c;

[0051] Where: V 1 Indicates the oxygen feed rate in Nm 3 / h; V 2 Indicates the amount of hydrogen chloride feed containing doping components, in Nm 3 / h; a represents the mass fraction of the doping component in hydrogen chloride, in %; b represents the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing the doping component to the total amount of oxygen after mixing; V 3 Indicates the circulating gas volume in Nm 3 / h; c represents the mass fraction of oxygen in the circulating gas, in %;

[0052] The calculation formula of the absorption liquid consumption is as follows:

[0053] m=k×V 4 ×(e+f);

[0054] Where: m represents the absorption liquid consumption, in g / h; k represents the absorption liquid coefficient, when the absorption liquid is sodium hydroxide solution, k = 3.571; when the absorption liquid is potassium hydroxide solution, k = 5; V 4 Indicates exhaust gas emissions in Nm 3 / h; e represents the mass fraction of chlorine in the tail gas, in %; f represents the mass fraction of carbon dioxide in the tail gas, in %.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] The method for reducing material consumption in the production of chlorine by oxidation of hydrogen chloride provided by the present invention can adjust the molar ratio of hydrogen chloride to oxygen and the reaction temperature by monitoring the content of doping components in hydrogen chloride, maintain the conversion rate at 70-75%, and further optimize the oxygen feed amount in real time, thereby reducing the oxygen consumption by 5-20 Nm 3 / t(Cl 2 ); By monitoring the content of circulating gas components, the optimal circulating gas volume can be adjusted in real time. Combined with the tail gas emission, the absorption liquid consumption can be reduced by 0.002-0.03t (absorption liquid) / t (Cl 2 ); The method only maintains a high conversion rate while reducing pure oxygen consumption and absorption liquid consumption by establishing a logical relationship between key parameters, without the need to modify the equipment or introduce a reaction promoter or replace the catalyst, and without modifying the original process, and has the characteristics of simple process. DETAILED DESCRIPTION

[0057] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0058] In the following examples, the concentration and flow rate of the byproduct hydrochloric acid obtained by the catalytic oxidation reaction are converted into the amount of unreacted hydrogen chloride, and the reaction conversion rate is calculated as follows: (1-amount of unreacted hydrogen chloride / amount of hydrogen chloride feed containing doping components)×100%, oxygen feed amount V 1 , the amount of hydrogen chloride feed containing doping components V 2 , Circulating gas volume V 3 And exhaust emissions V 4The mass fraction a of the doping component in the hydrogen chloride, the mass fraction c of the oxygen in the circulating gas, the mass fraction e of the chlorine in the tail gas and the mass fraction f of the carbon dioxide in the tail gas are measured by an online gas chromatograph.

[0059] Example 1

[0060] This embodiment provides a method for reducing material consumption in the production of chlorine by oxidation of hydrogen chloride, the method comprising the following steps:

[0061] The hydrogen chloride containing doping components, oxygen and circulating gas are mixed, and the feed temperature after mixing is 60°C; then a catalytic oxidation reaction is carried out under the action of a supported ruthenium catalyst, the temperature is 400°C, and the pressure is 300kPa(G); the obtained reaction gas is successively subjected to adsorption and rectification to obtain circulating gas and chlorine; part of the obtained circulating gas is recycled in the mixing, and part of it is absorbed by a sodium hydroxide solution as tail gas;

[0062] The doping components in the hydrogen chloride include carbon monoxide, carbon dioxide and nitrogen, and the mass fraction of the doping components is 2%; based on the total mass fraction of 100%, the circulating gas includes: 50% oxygen, 33% nitrogen, 10% carbon dioxide, and 7% chlorine; the component content of the tail gas is the same as the component content of the circulating gas; the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing the doping components to the total amount of oxygen after mixing is 2:1; based on the total mass percentage of 100wt%, the supported ruthenium catalyst includes 5wt% of ruthenium dioxide active components, and the rest is alumina carrier;

[0063] In the method, the content of doping components in hydrogen chloride and the content of components in the circulating gas are monitored to adjust the oxygen feed amount and the consumption of sodium hydroxide solution in real time; the oxygen feed amount V is obtained by calculation. 1 =15000×(1-0.02) / 2-5600×0.5=4550Nm 3 / h, oxygen consumption 142Nm 3 / t(Cl 2 ); The calculated sodium hydroxide solution consumption is m = 3.571 × 2400 × (0.07 + 0.1) = 1457 g / h, and the sodium hydroxide solution consumption is 0.045 t (NaOH) / t (Cl 2 ); the reaction conversion rate is 75%.

[0064] Example 2

[0065] This embodiment provides a method for reducing material consumption in the production of chlorine by oxidation of hydrogen chloride, the method comprising the following steps:

[0066] The hydrogen chloride containing doping components, oxygen and circulating gas are mixed, and the feed temperature after mixing is 40°C; then a catalytic oxidation reaction is carried out under the action of a supported ruthenium catalyst, the temperature is 330°C, and the pressure is 500kPa(G); the obtained reaction gas is subjected to membrane separation and rectification in sequence to obtain circulating gas and chlorine; part of the obtained circulating gas is recycled in the mixing, and part of it is absorbed by a sodium hydroxide solution as tail gas;

[0067] The doping components in the hydrogen chloride include carbon monoxide, carbon dioxide and nitrogen, and the mass fraction of the doping components is 1%; based on the total mass fraction of 100%, the circulating gas includes: 52% oxygen, 29% nitrogen, 11% carbon dioxide, and 8% chlorine; the component content of the tail gas is the same as the component content of the circulating gas; the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing doping components to the total amount of oxygen after mixing is 2:1; based on the total mass percentage of 100wt%, the supported ruthenium catalyst includes 0.1wt% of ruthenium dioxide active component, and the rest is alumina carrier;

[0068] In the method, the content of doping components in hydrogen chloride and the content of components in the circulating gas are monitored to adjust the oxygen feed amount and the consumption of sodium hydroxide solution in real time; the oxygen feed amount V is obtained by calculation. 1 =12000×(1-0.01) / 2-4000×0.52=3860Nm 3 / h, oxygen consumption 154Nm 3 / t(Cl 2 ); The calculated sodium hydroxide solution consumption is m = 3.571 × 2667 × (0.08 + 0.11) = 1809 g / h, and the sodium hydroxide solution consumption is 0.072 t (NaOH) / t (Cl 2 ); the reaction conversion rate was 73%.

[0069] Example 3

[0070] This embodiment provides a method for reducing material consumption in the production of chlorine by oxidation of hydrogen chloride, the method comprising the following steps:

[0071] The hydrogen chloride containing doping components, oxygen and circulating gas are mixed, and the feed temperature after mixing is 100°C; then a catalytic oxidation reaction is carried out under the action of a supported ruthenium catalyst, the temperature is 450°C, and the pressure is 200kPa(G); the obtained reaction gas is successively subjected to adsorption and rectification to obtain circulating gas and chlorine; part of the obtained circulating gas is recycled in the mixing, and part of it is absorbed by a sodium hydroxide solution as tail gas;

[0072] The doping components in the hydrogen chloride include carbon monoxide, carbon dioxide and nitrogen, and the mass fraction of the doping components is 3%; based on the total mass fraction of 100%, the circulating gas includes: 56% oxygen, 29% nitrogen, 10% carbon dioxide, and 5% chlorine; the component content of the tail gas is the same as the component content of the circulating gas; the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing doping components to the total amount of oxygen after mixing is 1.5:1; based on the total mass percentage of 100wt%, the supported ruthenium catalyst includes 10wt% of ruthenium dioxide active components, and the rest is alumina carrier;

[0073] In the method, the content of doping components in hydrogen chloride and the content of components in the circulating gas are monitored to adjust the oxygen feed amount and the consumption of sodium hydroxide solution in real time; the oxygen feed amount V is obtained by calculation. 1 =12000×(1-0.03) / 1.5-4200×0.56=5408Nm 3 / h, oxygen consumption 216Nm 3 / t(Cl 2 ); The calculated sodium hydroxide solution consumption is m = 3.571 × 4200 × (0.05 + 0.1) = 2250 g / h, and the sodium hydroxide solution consumption is 0.090 t (NaOH) / t (Cl 2 ); the reaction conversion rate was 73%.

[0074] Example 4

[0075] This embodiment provides a method for reducing material consumption in the production of chlorine by oxidation of hydrogen chloride, the method comprising the following steps:

[0076] The hydrogen chloride containing doping components, oxygen and circulating gas are mixed, and the feed temperature after mixing is 20°C; then a catalytic oxidation reaction is carried out under the action of a supported copper catalyst, the temperature is 300°C, and the pressure is 600kPa(G); the obtained reaction gas is subjected to adsorption and rectification in sequence to obtain circulating gas and chlorine; part of the obtained circulating gas is recycled in the mixing, and part of it is absorbed by a sodium hydroxide solution as tail gas;

[0077] The doping components in the hydrogen chloride include carbon monoxide, carbon dioxide and nitrogen, and the mass fraction of the doping components is 4%; based on the total mass fraction of 100%, the circulating gas includes: 60% oxygen, 15% nitrogen, 15% carbon dioxide, and 10% chlorine; the component content of the tail gas is the same as the component content of the circulating gas; the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing the doping components to the total amount of oxygen after mixing is 1:1; based on the total mass percentage of 100wt%, the supported copper catalyst includes 20wt% of the copper chloride active component, and the rest is the iron oxide carrier;

[0078] In the method, the content of doping components in hydrogen chloride and the content of components in the circulating gas are monitored to adjust the oxygen feed amount and the consumption of sodium hydroxide solution in real time; the oxygen feed amount V is obtained by calculation. 1 =5000×(1-0.04) / 1-1600×0.6=3840Nm 3 / h, oxygen consumption Nm 3 / t(Cl 2 ); The calculated sodium hydroxide solution consumption is m = 3.571 × 1067 × (0.1 + 0.15) = 952 g / h, and the sodium hydroxide solution consumption is 0.094 t (NaOH) / t (Cl 2 ); the reaction conversion rate was 71%.

[0079] Example 5

[0080] This embodiment provides a method for reducing material consumption in the production of chlorine by oxidation of hydrogen chloride, the method comprising the following steps:

[0081] The hydrogen chloride containing doping components, oxygen and circulating gas are mixed, and the feed temperature after mixing is 200°C; then a catalytic oxidation reaction is carried out under the action of a supported copper catalyst, the temperature is 500°C, and the pressure is 100kPa(G); the obtained reaction gas is sequentially subjected to adsorption and membrane separation to obtain circulating gas and chlorine; part of the obtained circulating gas is recycled in the mixing, and part of it is absorbed by a sodium hydroxide solution as tail gas;

[0082] The doping components in the hydrogen chloride include carbon monoxide, carbon dioxide and nitrogen, and the mass fraction of the doping components is 5%; based on the total mass fraction of 100%, the circulating gas includes: 40% oxygen, 30% nitrogen, 15% carbon dioxide, and 15% chlorine; the component content of the tail gas is the same as the component content of the circulating gas; the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing the doping components to the total amount of oxygen after mixing is 4:1; based on the total mass percentage of 100wt%, the supported copper catalyst includes 1wt% of the copper chloride active component, and the rest is the iron oxide carrier;

[0083] In the method, the content of doping components in hydrogen chloride and the content of components in the circulating gas are monitored to adjust the oxygen feed amount and the consumption of sodium hydroxide solution in real time; the oxygen feed amount V is obtained by calculation. 1 =8000×(1-0.05) / 4-300×0.4=1780Nm 3 / h, oxygen consumption 137Nm 3 / t(Cl 2 ); The calculated sodium hydroxide solution consumption is m = 3.571 × 1200 × (0.15 + 0.15) = 1286 g / h, and the sodium hydroxide solution consumption is 0.099 t (NaOH) / t (Cl2 ); The reaction conversion rate was 57%, which could not maintain a high conversion rate, and the by-product hydrochloric acid was high and the chlorine yield was low.

[0084] Example 6

[0085] This embodiment provides a method for reducing material consumption in the oxidation of hydrogen chloride to produce chlorine, which is different from Embodiment 1 in that, except for adjusting the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing doping components to the total amount of oxygen after mixing to 0.5:1, the rest is the same as Embodiment 1.

[0086] In this embodiment, the oxygen feed amount V is calculated 1 =15000×(1-0.02) / 0.5-20000×0.5=19400Nm 3 / h, oxygen consumption 605Nm 3 / t(Cl 2 ), indicating that the molar ratio of hydrogen chloride to oxygen is too low. While maintaining the reaction conversion rate, it will lead to a significant increase in oxygen consumption and increase the cost of chlorine production.

[0087] Example 7

[0088] This embodiment provides a method for reducing material consumption in the oxidation of hydrogen chloride to produce chlorine, which is different from Embodiment 1 in that, except for adjusting the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing doped components to the total amount of oxygen after mixing to 5:1, the rest is the same as Embodiment 1.

[0089] In this embodiment, the oxygen feed amount V is calculated 1 =15000×(1-0.02) / 5-300×0.5=2790Nm 3 / h, oxygen consumption 130Nm 3 / t(Cl 2 ), the reaction conversion rate is 50%, indicating that the molar ratio of hydrogen chloride to oxygen is too high, which will lead to a very low reaction conversion rate, a high by-product of hydrochloric acid and a low chlorine yield.

[0090] Example 8

[0091] This embodiment provides a method for reducing material consumption in preparing chlorine by oxidation of hydrogen chloride, which is different from Embodiment 1 in that, except that the temperature of the catalytic oxidation reaction is adjusted to 250° C., the rest is the same as Embodiment 1.

[0092] In this embodiment, the temperature of the catalytic oxidation reaction is too low, which will cause the reaction to not proceed, and ultimately cause the device to fail to operate normally.

[0093] Example 9

[0094] This embodiment provides a method for reducing material consumption in preparing chlorine by oxidation of hydrogen chloride, which is different from Embodiment 1 in that, except for adjusting the temperature of the catalytic oxidation reaction to 550° C., the rest is the same as Embodiment 1.

[0095] In this embodiment, the temperature of the catalytic oxidation reaction is too high, which will cause the catalyst to be destroyed and eventually cause the device to fail to operate normally.

[0096] Comparative Example 1

[0097] This comparative example provides a method for reducing material consumption in the production of chlorine by oxidation of hydrogen chloride. The difference from Example 1 is that the content of doping components in hydrogen chloride and the content of components in the circulating gas are not monitored, and the rest are the same as Example 1.

[0098] Fixed oxygen feed rate V 1 =15000 / 2-4000×0.5=5500Nm 3 / h, oxygen consumption 174Nm 3 / t(Cl 2 ); Fixed sodium hydroxide solution consumption 0.077t(NaOH) / t(Cl 2 ); the reaction conversion rate was 74%.

[0099] In this comparative example, since the content of doping components in hydrogen chloride and the content of components in the circulating gas are no longer monitored, the oxygen feed amount and tail gas emission are fixed by the chlorine-oxygen ratio, which will reduce the reaction conversion rate and cause pure oxygen consumption and sodium hydroxide solution waste.

[0100] In summary, the method for reducing material consumption in the production of chlorine by oxidation of hydrogen chloride provided by the present invention can adjust the molar ratio of hydrogen chloride to oxygen and the reaction temperature by monitoring the content of the doping component in hydrogen chloride, maintain the conversion rate at 70-75%, and further optimize the oxygen feed amount in real time, thereby reducing the oxygen consumption by 5-20 Nm 3 / t(Cl 2 ); By monitoring the content of circulating gas components, the optimal circulating gas volume can be adjusted in real time. Combined with the tail gas emission, the absorption liquid consumption can be reduced by 0.002-0.03t (absorption liquid) / t (Cl 2 ); The method only maintains a high conversion rate while reducing pure oxygen consumption and absorption liquid consumption by establishing a logical relationship between key parameters, without the need to modify the equipment or introduce a reaction promoter or replace the catalyst, and without modifying the original process, and has the characteristics of simple process.

[0101] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for reducing material consumption in the production of chlorine by oxidation of hydrogen chloride, characterized in that: The method comprises the following steps: The hydrogen chloride containing doping components, oxygen and circulating gas are mixed and then subjected to catalytic oxidation reaction, and the obtained reaction gas is subjected to impurity removal treatment and doping component removal in sequence to obtain circulating gas and chlorine; part of the obtained circulating gas is recycled in the mixing, and part of it is absorbed by an absorption liquid as tail gas; In the method, the oxygen feed amount and the absorption liquid consumption are adjusted in real time by monitoring the content of the doping component in the hydrogen chloride and the component content of the circulating gas.

2. The method according to claim 1, characterized in that The doping components in the hydrogen chloride include carbon monoxide, carbon dioxide and nitrogen, and the mass fraction of the doping components is ≤5%, preferably 1-2%.

3. The method according to claim 2, characterized in that The method satisfies at least one of the following ab: a. Based on the total mass fraction of 100%, the circulating gas includes: 40-60% oxygen, ≤35% nitrogen, ≤40% carbon dioxide, and 5-10% chlorine; preferably, based on the total mass fraction of 100%, the circulating gas includes: 45-52% oxygen, 29-33% nitrogen, 10-11% carbon dioxide, and 7-8% chlorine; b. The component content of the tail gas is the same as the component content of the circulating gas.

4. The method according to claim 3, characterized in that: The molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing the doping component to the total amount of oxygen after mixing is (1-4):1; preferably 2:

1.

5. The method according to claim 1, characterized in that The method satisfies at least one of the following AC: A. The feed temperature after mixing is 20-200°C; preferably 40-150°C; B. The temperature of the catalytic oxidation reaction is 300-500°C, preferably 380-450°C; the pressure is 100-600 kPa(G); preferably 200-500 kPa(G); C. The catalyst for the catalytic oxidation reaction includes a ruthenium-based catalyst and / or a copper-based catalyst.

6. The method according to claim 1, characterized in that The impurity removal treatment method includes any one of condensation, adsorption, distillation or membrane separation or a combination of at least two thereof; and / or, The method of removing the doping components includes any one of distillation, adsorption or membrane separation or a combination of at least two of them.

7. The method according to claim 1, characterized in that The absorption liquid includes sodium hydroxide solution and / or potassium hydroxide solution.

8. The method according to claim 1, characterized in that The calculation formula of the oxygen feed amount is as follows: V1=V2×(1-a) / b-V3×c; Where: V1 represents the oxygen feed rate, in Nm 3 / h; V2 represents the feed amount of hydrogen chloride containing doping components, in Nm 3 / h; a represents the mass fraction of the doping component in hydrogen chloride, in %; b represents the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing the doping component to the total amount of oxygen after mixing; V3 represents the circulating gas volume, in Nm 3 / h; c represents the mass fraction of oxygen in the circulating gas, in %.

9. The method according to claim 7, characterized in that: The calculation formula of the absorption liquid consumption is as follows: m = k × V4 × (e + f); Where: m represents the absorption liquid consumption, in g / h; k represents the absorption liquid coefficient, when the absorption liquid is sodium hydroxide solution, k = 3.571; when the absorption liquid is potassium hydroxide solution, k = 5; V4 represents the exhaust gas emission, in Nm 3 / h; e represents the mass fraction of chlorine in the tail gas, in %; f represents the mass fraction of carbon dioxide in the tail gas, in %.

10. The method according to claim 1, characterized in that The method comprises the following steps: The hydrogen chloride containing doping components, oxygen and circulating gas are mixed, and the feed temperature after mixing is 20-200°C; then a catalytic oxidation reaction is carried out at 300-500°C and 100-600kPa(G), and the obtained reaction gas is subjected to impurity removal treatment and doping component removal in turn to obtain circulating gas and chlorine; part of the obtained circulating gas is recycled in the mixing, and part of it is absorbed by an absorption liquid as tail gas; The doping components in the hydrogen chloride include carbon monoxide, carbon dioxide and nitrogen, and the mass fraction of the doping components is ≤5%; Taking the total mass fraction as 100%, the circulating gas comprises: 40-60% oxygen, ≤35% nitrogen, ≤40% carbon dioxide, and 5-10% chlorine; the component content of the tail gas is the same as the component content of the circulating gas; the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing doped components to the total amount of oxygen after mixing is (1-4):1; In the method, the oxygen feed amount and the absorption liquid consumption are adjusted in real time by monitoring the content of the doping component in the hydrogen chloride and the component content of the circulating gas; The calculation formula of the oxygen feed amount is as follows: V1=V2×(1-a) / b-V3×c; Where: V1 represents the oxygen feed rate, in Nm 3 / h; V2 represents the feed amount of hydrogen chloride containing doping components, in Nm 3 / h; a represents the mass fraction of the doping component in hydrogen chloride, in %; b represents the molar ratio of the total amount of hydrogen chloride in the hydrogen chloride containing the doping component to the total amount of oxygen after mixing; V3 represents the circulating gas volume, in Nm 3 / h; c represents the mass fraction of oxygen in the circulating gas, in %; The calculation formula of the absorption liquid consumption is as follows: m = k × V4 × (e + f); Where: m represents the absorption liquid consumption, in g / h; k represents the absorption liquid coefficient, when the absorption liquid is sodium hydroxide solution, k = 3.571; when the absorption liquid is potassium hydroxide solution, k = 5; V4 represents the exhaust gas emission, in Nm 3 / h; e represents the mass fraction of chlorine in the tail gas, in %; f represents the mass fraction of carbon dioxide in the tail gas, in %.