CN114426256B - Gas phase hydrogen sulfide coupling hydrogen production system and method - Google Patents

Abstract

The invention discloses a gas phase hydrogen sulfide coupling hydrogen production system and a method, comprising an acid gas input pipeline, a gas phase reaction tower, a cyclone separator, a primary heater, a secondary heater, a decomposition tower, a primary condenser and a secondary condenser; the top outlet of the cyclone separator is communicated with the heat absorption side inlet of the primary heater, the heat absorption side outlet of the primary heater is communicated with the inlet of the secondary heater, the outlet of the secondary heater is communicated with the inlet of the decomposing tower, the bottom outlet of the decomposing tower is communicated with the heat emission side inlet of the primary condenser, the heat emission side outlet of the primary condenser is communicated with the inlet of the secondary condenser, the outlet of the secondary condenser is communicated with the inlet of the gas phase reaction tower, and the acid gas input pipeline is communicated with the inlet of the gas phase reaction tower; low cost, simple separation and good economical efficiency.

Description

A gas-phase hydrogen sulfide coupled hydrogen production system and method

technical field

The invention belongs to the technical field of chemical engineering and environmental protection, and relates to a gas-phase hydrogen sulfide coupled hydrogen production system and method.

Background technique

Sulfur is associated with coal, petroleum, and natural gas. Hydrogen sulfide is a by-product in the process of coal chemical industry, petroleum cracking, and natural gas production. Hydrogen sulfide is a highly toxic gas and an important source of pollution in the chemical industry. Hydrogen sulfide needs to be recovered in the end. deal with. There are several methods for hydrogen sulfide recovery.

At present, sulfur-iodine cycle high-temperature hydrolysis hydrogen production is one of the research hotspots of green hydrogen production. The reaction formula is shown in formula (1-3). The hydrogen production process requires a high temperature above 850°C to pyrolyze sulfuric acid into sulfur dioxide, water, sulfur dioxide and iodine. Hydrogen iodide is produced at room temperature, and hydrogen iodide decomposes into iodine and hydrogen at temperatures above 300°C. The difficulty in realizing this process lies in:

1) The high temperature of 850°C required for pyrolysis of sulfuric acid has high energy consumption and is difficult to meet;

2) Sulfuric acid is a highly corrosive substance, and materials that can resist high temperature corrosion are very expensive;

3) sulfuric acid and hydroiodic acid belong to azeotrope, and separation is difficult;

4) The economy of hydrogen production by pyrolysis of sulfuric acid is poor.

2H ₂ SO ₄ =2SO ₂ +O ₂ +2H ₂ O

SO ₂ +2H ₂ O+I ₂ ＝H ₂ SO ₄ +2HI

2HI=H ₂ +I ₂ .

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art, and provide a gas-phase hydrogen sulfide coupled hydrogen production system and method, which has the characteristics of low energy consumption, low cost, simple separation and good economy.

In order to achieve the above object, the gas phase hydrogen sulfide coupled hydrogen production system of the present invention includes an acid gas input pipeline, a gas phase reaction tower, a cyclone separator, a primary heater, a secondary heater, a decomposition tower, a primary condenser and secondary condenser;

The top outlet of the cyclone separator is connected to the heat-absorbing side inlet of the primary heater, the heat-absorbing side outlet of the primary heater is connected to the inlet of the secondary heater, and the outlet of the secondary heater is connected to the inlet of the decomposition tower The outlet at the bottom of the decomposition tower is connected with the heat release side inlet of the primary condenser, the heat release side outlet of the primary condenser is connected with the entrance of the secondary condenser, and the outlet of the secondary condenser is connected with the gas phase reaction tower. The inlet is connected, and the acid gas input pipeline is connected with the inlet of the gas phase reaction tower.

The heat release side of the primary heater communicates with the heat absorption side of the primary condenser.

The gas phase reaction tower adopts shell and tube reactor.

The secondary heater adopts high-temperature steam or electric heating.

The secondary condenser is cooled by circulating water.

The outlet of the secondary condenser communicates with the inlet of the gas phase reaction tower through a liquid iodine pump.

The method for gas-phase hydrogen sulfide coupling hydrogen production described in the present invention comprises the following steps:

Hydrogen sulfide and iodine vapor react in the gas phase reaction tower to generate sulfur element and hydrogen iodide. Among them, the hydrogen iodide, sulfur element and excess iodine vapor generated by the reaction are mixed into the cyclone separator for separation, and the separated sulfur The elemental substance is discharged, and the separated hydrogen iodide and excess iodine vapor enter the primary heater to heat up, then enter the secondary heater to heat up, and finally enter the decomposition tower, where hydrogen iodide decomposes under the action of the catalyst , generate iodine vapor and hydrogen, wherein, the generated hydrogen is discharged from the top of the decomposition tower, and the generated iodine vapor is discharged from the bottom of the decomposition tower into the primary condenser for cooling, and then enters the secondary condenser for cooling to become The liquid iodine is then transported to the gas phase reaction tower.

The molar ratio of iodine to hydrogen sulfide in the gas phase reaction tower is 3-5.

The present invention has the following beneficial effects:

The gas-phase hydrogen sulfide coupled hydrogen production system and method of the present invention use a gas-phase reaction tower and a decomposition tower as reactors during specific operations. Compared with the sulfur-iodide cycle hydrogen production process, there is no separation process between sulfuric acid and hydroiodic acid. Sulfuric acid-free decomposition process, simple equipment, reduced operation and maintenance costs. Compared with the reaction process of liquid hydrogen sulfide and iodine solution at normal temperature, the present invention has relatively simple equipment. In addition, compared with hydrogen production by sulfur-iodine cycle high-temperature hydrolysis, the present invention does not need the high temperature of 850°C required by pyrolysis of sulfuric acid, and reduces energy consumption. At the same time, it should be noted that the present invention will not produce sulfuric acid or other pollution during the whole process, and the manufacturing and operating costs are relatively low; at the same time, the present invention uses hydrogen sulfide coupled with a green hydrogen production process to reuse highly toxic waste, Turning waste into treasure has high environmental protection benefits.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Among them, 1 is a gas phase reaction tower, 2 is a cyclone separator, 3 is a primary heater, 4 is a secondary heater, 5 is a decomposition tower, 6 is a primary condenser, 7 is a secondary condenser, and 8 is a liquid iodine pump.

Detailed ways

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only The embodiments are a part of the present invention, not all embodiments, and are not intended to limit the scope of the present invention. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

The schematic diagrams of the structures according to the disclosed embodiments of the present invention are shown in the accompanying drawings. The figures are not drawn to scale, with certain details exaggerated and possibly omitted for clarity of presentation. The shapes of various regions and layers shown in the figure and their relative sizes and positional relationships are only exemplary, and may deviate due to manufacturing tolerances or technical limitations in practice, and those skilled in the art may Regions/layers with different shapes, sizes, and relative positions can be additionally designed as needed.

With reference to Fig. 1, the system of gas phase hydrogen sulfide coupled hydrogen production of the present invention comprises acid gas input pipeline, gas phase reaction tower 1, cyclone separator 2, primary heater 3, secondary heater 4, decomposition tower 5, a Stage condenser 6, secondary condenser 7 and liquid iodine pump 8;

The top outlet of the cyclone separator 2 is connected with the endothermic side inlet of the primary heater 3, the endothermic side outlet of the primary heater 3 is connected with the inlet of the secondary heater 4, and the outlet of the secondary heater 4 is connected with the The inlet of decomposition tower 5 is connected, and the bottom outlet of decomposition tower 5 is connected with the heat release side inlet of primary condenser 6, and the heat discharge side outlet of primary condenser 6 is connected with the entrance of secondary condenser 7, two The outlet of the first stage condenser 7 is connected with the inlet of the gas phase reaction tower 1 through the liquid iodine pump 8, the heat release side of the first stage heater 3 is connected with the heat absorption side of the first stage condenser 6, and the acid gas input pipeline is reacted with the gas phase The entrance of Tower 1 is connected.

It should be noted that, in the present invention, the gas phase reaction tower 1 is used for the reaction of _H2S in acid gas and _I2 steam to generate HI and S simple substances, and the reaction temperature is controlled at (120°C-180°C), and the gas phase reaction tower 1 can A tubular reactor or other types of reactors are used to control the molar ratio of iodine to hydrogen sulfide to be 3-5.

Cyclone separator 2 is used to separate sulfur particles from other gases, wherein hydrogen iodide, small sulfur particles and excess iodine vapor are mixed and output from gas phase reaction tower 1, and then enter cyclone separator 2 to separate sulfur particles from other gases Separation, the sulfur is discharged after being deposited at the bottom of the cyclone separator 2.

The primary heater 3 is used to heat the decomposed high-temperature iodine vapor (400°C-480°C) into hydrogen iodide, and at the same time cool down the high-temperature iodine vapor. The temperature of the heated hydrogen iodide is about 320°C-480°C. The steam temperature is reduced to 200°C-280°C, and the heat exchange of the system itself is used to save energy consumption.

The secondary heater 4 is used to reheat the hydrogen iodide output from the primary heater 3 to 400°C-480°C, and the secondary heater 4 adopts high-temperature steam or electric heating.

The decomposition tower 5 is used to decompose high-temperature hydrogen iodide (400°C-480°C) into hydrogen and iodine vapor under the conditions of a pressure of 0.1MPa-2.7MPa and a catalyst, wherein the hydrogen gas is discharged from the top of the decomposition tower 5, and the high-temperature iodine vapor Discharge from the bottom of decomposition tower 5;

The primary condenser 6 is used to transfer the heat of the high-temperature iodine vapor (400°C-480°C) to the primary heater 3;

The secondary condenser 7 is used to further cool down the iodine vapor output from the primary condenser 6 to 130°C-170°C to become liquid iodine. The secondary condenser 7 uses circulating water or other methods to cool down.

Concrete work process of the present invention is:

The temperature in the gas phase reaction tower 1 is between 120°C and 180°C, and the pressure is between 0.1MPa-2.7MPa. Hydrogen sulfide and iodine vapor react to generate sulfur element and hydrogen iodide, wherein the hydrogen iodide, sulfur The elemental substance and excess iodine vapor are mixed into the cyclone separator 2 for separation, wherein the separated sulfur elemental substance is discharged, and the separated 120°C-180°C hydrogen iodide and excess iodine vapor enter the primary heater 3 and heat up to 320°C-380°C, then enter the secondary heater 4 to heat up to 400°C-480°C, and finally enter the decomposition tower 5, and decompose hydrogen iodide under the action of the catalyst to generate iodine vapor and hydrogen gas, among which , the generated hydrogen is discharged from the top of the decomposition tower 5, and the iodine vapor generated is discharged through the bottom of the decomposition tower 5 and enters the primary condenser 6 to cool down to 200°C-280°C, and then enters the secondary condenser 7 to cool down to Between 130°C and 170°C to become liquid iodine, and then transported to the gas phase reaction tower 1 through the liquid iodine pump 8, and after expansion in the gas phase reaction tower 1, it becomes iodine vapor and reacts with hydrogen sulfide in the acid gas to complete a cycle process.

Wherein, the chemical reaction involved in the present invention is:

H ₂ S+I ₂ =2HI+S↓ (1)

2HI＝H ₂ +I ₂ (2)

I ₂ +I ⁻ =I ₃ ⁻ (3).

Claims (2)

1. the system for preparing hydrogen by coupling gas-phase hydrogen sulfide is characterized by comprising an acid gas input pipeline, a gas-phase reaction tower (1), a cyclone separator (2), a primary heater (3), a secondary heater (4), a decomposition tower (5), a primary condenser (6) and a secondary condenser (7);

the top outlet of the cyclone separator (2) is communicated with the heat absorption side inlet of the primary heater (3), the heat absorption side outlet of the primary heater (3) is communicated with the inlet of the secondary heater (4), the outlet of the secondary heater (4) is communicated with the inlet of the decomposing tower (5), the bottom outlet of the decomposing tower (5) is communicated with the heat emission side inlet of the primary condenser (6), the heat emission side outlet of the primary condenser (6) is communicated with the inlet of the secondary condenser (7), the outlet of the secondary condenser (7) is communicated with the inlet of the gas phase reaction tower (1), and the acid gas input pipeline is communicated with the inlet of the gas phase reaction tower (1);

the heat-absorbing side of the primary condenser (6) is communicated with the heat-releasing side of the primary heater (3);

the gas phase reaction tower (1) adopts a tubular reactor;

the secondary heater (4) adopts high-temperature steam or electric heating mode;

the secondary condenser (7) is cooled by circulating water;

the outlet of the secondary condenser (7) is communicated with the inlet of the gas phase reaction tower (1) through a liquid iodine pump (8).

2. A method for preparing hydrogen by coupling gas phase hydrogen sulfide, which is characterized by comprising the following steps:

hydrogen sulfide and iodine vapor react in a gas phase reaction tower (1) to generate elemental sulfur and hydrogen iodide, wherein the elemental sulfur, elemental sulfur and excessive iodine vapor generated by the reaction are mixed and enter a cyclone separator (2) for separation, the separated elemental sulfur is discharged, the separated elemental sulfur and excessive iodine vapor enter a first-stage heater (3) for heating, then enter a second-stage heater (4) for heating, finally enter a decomposition tower (5), the hydrogen iodide is decomposed under the action of a catalyst to generate iodine vapor and hydrogen, the generated hydrogen is discharged from the top of the decomposition tower (5), the generated iodine vapor is discharged from the bottom of the decomposition tower (5) for cooling, and then enters a second-stage condenser (7) for cooling to become liquid iodine, and the liquid iodine is conveyed into the gas phase reaction tower (1);

the molar ratio of iodine to hydrogen sulfide in the gas phase reaction tower (1) is 3-5.

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