DE202020005861U1 - Hydrogen sulphide thermal cracking reactor to obtain sulfur and hydrogen - Google Patents

Abstract

Reactor for the thermal cracking of hydrogen sulphide to obtain sulfur and hydrogen, in which a gas (3) containing hydrogen sulphide or a gas mixture is introduced into a chamber (1, 4), heated in a manner known per se and thermally broken down into its components sulfur and hydrogen , whereby the gas (3) in the chamber (1, 4) is kept under constant rotation and undergoes a separation of the colder and therefore heavier gas layer and the hotter and therefore lighter gas layer due to the action of centrifugal force, and the hotter (lighter) gas layer is thereby displaced Gas in the direction of the axis of rotation of the chamber (1.4) and the colder (heavier) gas in the direction of the chamber wall, with the consequences that heat losses through the colder gas layer in the area of the chamber walls are minimized due to the low thermal conductivity of the gases and thus high temperatures in the Area of the axis of rotation of the chamber can be achieved, with no plasma in the working area of the comb it (1, 4) is present, characterized in that heavier sulfur is displaced towards the chamber walls under the action of centrifugal force and lighter hydrogen collects in the region of the axis of rotation of the chamber (1, 4).

Description

The invention relates to a reactor for the production of sulfur and hydrogen from gases containing hydrogen sulfide by thermal cracking of the hydrogen sulfide.

Sulfur is an important raw material in both the chemical and pharmaceutical industries and is used in the production of sulfuric acid, dyes, pesticides and artificial fertilizers, among other things. Sulfur is produced in large quantities in the separation of hydrogen sulfide from natural gases and in the hydrodesulfurization of petroleum in refineries, where the hydrogen sulfide is oxidized to liquid sulfur using the Claus process. For environmental and safety reasons, sulfur or hydrogen sulfide must be removed from sulphur-containing raw materials before such materials are used or released into the atmosphere.

The modified Claus process is currently the most widely used process for obtaining sulfur from H ₂ S-containing gases. The Claus process consists of several stages: in the thermal stage, H ₂ S is oxidized by partial combustion with the air and up to 70% sulfur is recovered. More sulfur is recovered in the next two or three catalytic stages. The remaining sulfur compounds are then removed from the Claus tail gases using various fine desulfurization processes. The costs of sulfur production increase significantly due to the catalytic stages and the fine desulfurization. Another disadvantage of the process is that no hydrogen can be obtained in the Claus process, since hydrogen is converted into water.

In numerous patents, such as US4632818A , US4684514A , US20050201924A1 , US7226572B1 , US7501111B2 , various improvements to the Claus method have been proposed. However, the disadvantage of the Claus process is that it has multiple stages with numerous heating and cooling processes at individual stages, which reduces the overall process efficiency and increases production costs.

In DE2915210A1 discloses a process for producing hydrogen and sulfur from hydrogen sulfide by thermal cracking, where the gas containing hydrogen sulfide is passed through a cracking zone maintained at a temperature of 850 to 1600°C, the cracked gas is cooled to temperatures in the range of 110 to 150°C, the elementary sulfur condensed in the process is separated from the cracked gas, the hydrogen sulfide which has not been cracked is separated from the cracked gas, the separated hydrogen sulfide is returned to the cracking zone and the gas remaining in the separation is drawn off as a hydrogen-rich gas. The disadvantage of this process is that after cooling, only part of the sulfur is present in elemental form and hydrogen sulfide that has not been split must be fed back into the cracking zone several times, so that the process remains uneconomical.

It is an object of the invention to provide a highly efficient thermal reactor for the recovery of elemental sulfur from hydrogen sulfide with an effective separation of fission products, whereby hydrogen can be produced as a by-product. Another task is to ensure insulation of hot gases from construction walls and thereby high gas temperatures with minimal heat loss in the work area.

The object is achieved with a method which is characterized in that a gas containing hydrogen sulfide is heated to a temperature of >800 °C in a chamber and kept under constant rotation, with the rotating gas being separated from colder gas by the action of centrifugal force and thus heavier and hotter and thus lighter gas layers, causing the hotter (lighter) gas to be displaced into the center of rotation of the chamber and the colder (heavier) gas toward the chamber wall. Since gases have a very low thermal conductivity, a heat-insulating gas layer forms in the center between the chamber walls and the hot gas masses, which minimizes heat losses and prevents the chamber walls from overheating. High temperatures can be reached in the central area of the chamber, so that hydrogen sulfide is thermally broken down into sulfur and hydrogen. The cleavage proceeds according to the reaction equation: $$H_{2}S\rightleftarrows \raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="DE202020005861U1\_0002.png"\; state="\{\{state\}\}">S</figure-callout>}}_2+{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="DE202020005861U1\_0002.png"\; state="\{\{state\}\}">H</figure-callout>}}_2.$$

Since the sulfur gas is 32 times heavier than hydrogen gas, it is thrown towards the chamber walls under the action of centrifugal force and hydrogen remains in the central area of the chamber. This ensures effective separation of the reaction products. The sulfur separated by centrifugal force is then discharged from the reactor in the form of a gas or liquid (at a wall temperature below the sulfur boiling point of 444.6 °C) and treated depending on the intended use.

The invention is illustrated schematically in the drawings 1 until 5 explained.

1 Figure 1 shows an embodiment 1 with a rotating tube (1) with open ends (2), wherein a gas (3) containing hydrogen sulfide is introduced at one end of the tube and heated in a manner known per se. The reaction products flow out at the other end. Inside the tube (1), the gas is kept at a high temperature according to the invention and the tube walls remain at a lower temperature thanks to the heat-insulating gas layer, with hydrogen sulfide being broken down into its components and the resulting elemental sulfur and hydrogen being separated according to the invention and discharged separately.

In the 2 Example 2 of the invention is shown where the gas containing hydrogen sulfide (3) is rotated in a non-rotating tube (4) by a bladed impeller or fan (5). The gas is heated as in Example 1 and the reaction products formed are separated and removed according to the invention.

3 represents an example 3 for a closed container (6), the interior of the container (6) being under normal, negative or positive pressure. According to the invention, a gas (3) containing hydrogen sulfide is kept at a high temperature in the container (6) according to exemplary embodiment 1 or 2, i.e. in a rotating tube (1) or in the non-rotating tube (4), and the reaction products are separated and discharged according to the invention .

During rotary motion, the centrifugal force acts only in the radial direction, which means that the thermal insulation according to the invention does not function in the axial direction. In order to minimize this disadvantage, the tube length can be selected to be significantly larger than the tube diameter (eg in a ratio of 10 to 1). This disadvantage cannot arise when a chamber is annular, such as a torus or two tubes connected at both ends, so that there are no free ends of the hot gas vortex. The embodiment 4 ( 4 ) shows possible configurations (4.1, 4.2, 4.3).

The chamber (1, 4) can be oriented horizontally or with an inclination, see 5 . If the outlet end of the chamber is directed downwards (5.1), discharge of solid or liquid reaction products is facilitated thanks to the action of earth gravity. On the other hand, with an orientation upwards (5.2), lighter gaseous products can escape better. If the chamber (4) is built according to example 2 and has a kinked shape (5.3), liquid reaction products can advantageously be collected in the middle and be better discharged from there.

The present invention offers several advantages. The entire process can be carried out in one step up to the complete decomposition of hydrogen sulphide into elementary sulfur and hydrogen gas, there is no need for fine desulfurization. No catalysts are required, compared to the Claus process there are significantly lower investment and operating costs, which leads to a significant reduction in the production costs of sulfur production.

By using a reactor constructed in accordance with the invention for sulfur production, heat losses and thereby energy consumption can be significantly reduced. To reduce energy demand and environmental emissions, part of the hydrogen produced in the reactor can be used as fuel to generate the temperature needed for hydrogen sulfide decomposition.

While the Claus process is suitable for gas streams with more than 30% H ₂ S content, gases with lower concentrations of hydrogen sulphide can also be used in the patenting reactor, so that the reactor can be used for fine desulfurization, for example in oil refineries .

Reference List

1

rotating chamber

2

chamber end

3

gas

4

Non-rotating chamber

4.1

Structure 1

4.2

design 2

4.3

Structure 3

5

Impeller with blades or fan

5.1

Orientation down

5.2

Orientation up

5.3

Kinked construction

6

container

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US4632818A [0004]
• US4684514A [0004]
• US20050201924A1 [0004]
• US7226572B1 [0004]
• US7501111B2 [0004]
• DE 2915210 A1 [0005]

Claims (11)

Reactor for the thermal cracking of hydrogen sulphide to obtain sulfur and hydrogen, in which a gas (3) containing hydrogen sulphide or a gas mixture is introduced into a chamber (1, 4), heated in a manner known per se and thermally broken down into its components sulfur and hydrogen , whereby the gas (3) in the chamber (1, 4) is kept under constant rotation and undergoes a separation of the colder and therefore heavier gas layer and the hotter and therefore lighter gas layer due to the action of centrifugal force, and the hotter (lighter) gas layer is thereby displaced Gas in the direction of the axis of rotation of the chamber (1.4) and the colder (heavier) gas in the direction of the chamber wall, with the consequences that heat losses through the colder gas layer in the area of the chamber walls are minimized due to the low thermal conductivity of the gases and thus high temperatures in the Area of the axis of rotation of the chamber can be achieved, with no plasma in the working area of the comb it (1, 4) is present, characterized in that heavier sulfur is displaced towards the chamber walls under the effect of centrifugal force and lighter hydrogen collects in the region of the axis of rotation of the chamber (1, 4). reactor after claim 1 , characterized in that the sulfur produced is discharged from the chamber (1, 4) as a gas. reactor after claim 1 , characterized in that the resulting sulfur is discharged from the chamber (1, 4) as a liquid. reactor after claim 2 or 3 , characterized in that the rotation of the gas (3) is achieved by rotation of the chamber (1) and/or by at least one impeller with blades (5) and/or at least one fan (5) and/or by gas flows. Reactor after one of Claims 1 until 4 , characterized in that the rotational speed is set to at least 50 revolutions per minute. Reactor after one of Claims 1 until 5 , characterized in that the temperature in the central area of the chamber (1, 4) is adjusted to 800 to 1600 °C, preferably to 900 to 1100 °C. Reactor after one of Claims 1 until 5 , characterized in that the temperature in the central area of the chamber (1, 4) is set to less than 800 °C or greater than 1600 °C. Reactor after one of Claims 1 until 7 , characterized in that for heating the gas (3) in the chamber (1, 4) part of the generated hydrogen is burned. Reactor after one of Claims 1 until 8th , characterized in that the gas (3) in the chamber (1, 4) installed in a closed container (6) is under normal, negative or positive pressure. Reactor after one of Claims 1 until 9 , characterized in that the chamber (1.4) is directed horizontally or at an angle of inclination from 0° to 90° (5.1) or from 0° to -90° (5.2) or the chamber (4) has a kinked shape (5.3 ) Has. Reactor after one of Claims 1 until 10 , characterized in that the gas (3) in the chamber (1, 4) contains other sulfur compounds, hydrocarbons, water vapor, ammonia and/or mixtures thereof in addition to the hydrogen sulphide.

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