CN114426256A - A gas-phase hydrogen sulfide coupled hydrogen production system and method - Google Patents

Abstract

The invention discloses a system and a method for preparing hydrogen by coupling gas-phase hydrogen sulfide, which comprises 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 first-stage heater, the heat absorption side outlet of the first-stage heater is communicated with the inlet of the second-stage heater, the outlet of the second-stage heater is communicated with the inlet of the decomposing tower, the bottom outlet of the decomposing tower is communicated with the heat release side inlet of the first-stage condenser, the heat release side outlet of the first-stage condenser is communicated with the inlet of the second-stage condenser, the outlet of the second-stage 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 environmental protection, and relates to a gas-phase hydrogen sulfide coupling hydrogen production system and method.

Background technique

Sulfur co-exists in coal, oil and natural gas. In the process of coal chemical industry, oil cracking, and natural gas production, most of the by-product hydrogen sulfide is generated. Hydrogen sulfide is a highly toxic gas and an important source of pollution in the chemical industry. Finally, hydrogen sulfide needs to be recovered. deal with. There are various methods for recovering hydrogen sulfide.

At present, hydrogen production by high-temperature hydrolysis of sulfur-iodine cycle is one of the hot spots in green hydrogen production research. Hydrogen iodide is generated at room temperature, and hydrogen iodide is decomposed into iodine and hydrogen at temperatures above 300 °C. The difficulty in realizing this process is:

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

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

3) Sulfuric acid and hydroiodic acid belong to azeotrope and are difficult to separate;

4) The economical efficiency of pyrolysis of sulfuric acid for hydrogen production 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 .

SUMMARY OF THE INVENTION

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

In order to achieve the above-mentioned purpose, the system of the gas phase hydrogen sulfide coupling hydrogen production system of the present invention comprises 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 with the heat-absorbing side inlet of the primary heater, the heat-absorbing side outlet of the primary heater is connected with the inlet of the secondary heater, and the outlet of the secondary heater is connected with the inlet of the decomposition tower The bottom outlet of the decomposition tower is communicated with the exothermic side inlet of the primary condenser, the exothermic side outlet of the primary condenser is communicated with the inlet of the secondary condenser, and the outlet of the secondary condenser is communicated with the outlet of the gas phase reaction column. The inlet is communicated, and the acid gas input pipeline is communicated 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 a tubular reactor.

The secondary heater adopts high temperature steam or electric heating.

The secondary condenser is cooled with circulating water.

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

The method for producing hydrogen by coupling gas-phase hydrogen sulfide according to the present invention comprises the following steps:

Hydrogen sulfide and iodine vapor react in a gas-phase reaction tower to generate elemental sulfur and hydrogen iodide, wherein the hydrogen iodide, elemental sulfur and excess iodine vapor generated by the reaction are mixed into a cyclone for separation, wherein 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 heat up, and finally enter the decomposition tower, and the hydrogen iodide is decomposed 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 to cool down, and then enters the secondary condenser to cool down to become The liquid iodine is then sent 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 adopts the gas-phase reaction tower and the decomposition tower as the reactor during the specific operation. The decomposition process without sulfuric acid, the equipment is simple, and the operation and maintenance cost is reduced. Compared with the reaction process of liquid hydrogen sulfide and iodine solution at normal temperature, the device of the invention is relatively simple. In addition, compared with the sulfur-iodine cycle high-temperature hydrolysis to produce hydrogen, the present invention does not require a high temperature of 850° C. required by sulfuric acid pyrolysis, and reduces energy consumption. At the same time, it should be noted that the present invention will not produce sulfuric acid or other pollution in the whole process, and the manufacturing and operating costs are low; Turning waste into treasure has high environmental protection benefits.

Description of drawings

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

Wherein, 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 make those skilled in the art 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 with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only The embodiments are part of the present invention, not all of the embodiments, and are not intended to limit the scope of the present disclosure. Furthermore, 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 creative efforts shall fall within the protection scope of the present invention.

The accompanying drawings show a schematic structural diagram of an embodiment according to the disclosure of the present invention. The figures are not to scale, some details have been exaggerated for clarity, and some details may have been omitted. The shapes of various regions and layers shown in the figures and their relative sizes and positional relationships are only exemplary, and in practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art should Regions/layers with different shapes, sizes, relative positions can be additionally designed as desired.

Referring to Fig. 1 , the system for coupling gas-phase hydrogen sulfide to hydrogen production according to the present invention comprises an acid gas input pipeline, a gas-phase reaction tower 1, a cyclone 2, a primary heater 3, a secondary heater 4, a decomposition tower 5, a Stage condenser 6, secondary condenser 7 and liquid iodine pump 8;

The top outlet of the cyclone separator 2 is communicated with the heat-absorbing side inlet of the primary heater 3, the heat-absorbing side outlet of the primary heater 3 is communicated with the inlet of the secondary heater 4, and the outlet of the secondary heater 4 is communicated with the inlet of the secondary heater 4. The inlet of the decomposition tower 5 is communicated, the bottom outlet of the decomposition tower 5 is communicated with the heat release side inlet of the primary condenser 6, and the heat release side outlet of the primary condenser 6 is communicated with the inlet of the secondary condenser 7, and two The outlet of the stage condenser 7 is communicated with the inlet of the gas phase reaction tower 1 through the liquid iodine pump 8, the exothermic side of the primary heater 3 is communicated with the heat absorption side of the primary 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 H ₂ S and I ₂ steam in the acid gas to generate HI and S elemental substances, and the reaction temperature is controlled at (120°C-180°C), and the gas phase reaction tower 1 can Using a tubular reactor or other types of reactors, the molar ratio of iodine to hydrogen sulfide is controlled to be 3-5.

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

The first-stage 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 the high-temperature iodine vapor. The heated hydrogen iodide temperature is about 320°C-480°C, and the iodine The steam temperature is reduced to 200°C-280°C, and the system's own heat is used for heat exchange to save energy.

The secondary heater 4 is used to reheat the hydrogen iodide output by 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 the 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 is discharged from the top of the decomposition tower 5, and the high-temperature iodine vapor is discharged. 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 the iodine vapor output from the primary condenser 6 to 130°C-170°C to become liquid iodine, and the secondary condenser 7 uses circulating water or other methods to cool down.

The concrete working 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 and 2.7MPa. The hydrogen sulfide reacts with the iodine vapor to generate elemental sulfur and hydrogen iodide. The elemental substance and the 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 warm up to 100°C. 320 ℃-380 ℃, then enter the secondary heater 4 to heat up to 400 ℃-480 ℃, and finally enter the decomposition tower 5, and the hydrogen iodide is decomposed under the action of the catalyst to generate iodine vapor and hydrogen, among which , the generated hydrogen is discharged from the top of the decomposition tower 5, and the generated iodine vapor is discharged through the bottom of the decomposition tower 5 and enters the primary condenser 6 to be cooled to 200 ℃-280 ℃, 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, after the expansion in the gas phase reaction tower 1, it becomes the reaction between iodine vapor and 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 (8)

1. a system for producing 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 decomposition tower (5), the bottom outlet of the decomposition tower (5) is communicated with the heat release side inlet of the primary condenser (6), the heat release 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).

2. A system for the production of hydrogen gas by coupling gaseous phase hydrogen sulfide according to claim 1, wherein the exothermic side of the primary heater (3) is in communication with the endothermic side of the primary condenser (6).

3. The system for producing hydrogen gas by coupling gas-phase hydrogen sulfide as claimed in claim 1, wherein the gas-phase reaction tower (1) adopts a tubular reactor.

4. The system for producing hydrogen gas by coupling gas-phase hydrogen sulfide as claimed in claim 1, wherein the secondary heater (4) adopts high-temperature steam or electric heating mode.

5. A system for the production of hydrogen from gas phase hydrogen sulfide coupled with the production of hydrogen according to claim 1, wherein the secondary condenser (7) is cooled with circulating water.

6. The system for producing hydrogen gas by coupling gas phase hydrogen sulfide as claimed in claim 1, wherein 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).

7. A method for producing hydrogen by coupling gas-phase hydrogen sulfide 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, hydrogen iodide, sulfur simple substance and excessive iodine steam generated by the reaction are mixed and enter a cyclone separator (2) for separation, wherein the separated elemental sulfur is discharged, the separated hydrogen iodide and excessive iodine vapor enter a primary heater (3) for heating, then enter a secondary heater (4) for heating and heating, finally enter a decomposition tower (5) and are 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 steam is discharged from the bottom of the decomposition tower (5), enters a primary condenser (6) for cooling, enters a secondary condenser (7) for cooling to form liquid iodine, and then is conveyed to the gas phase reaction tower (1).

8. The method for producing hydrogen from gas phase hydrogen sulfide coupled with claim 7, wherein the molar ratio of iodine to hydrogen sulfide in the gas phase reaction tower (1) is 3-5.

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