RU2535041C2 - Gas flow desulfurisation procedure - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is related to petrochemical and gas industries and may be used during wells development at deposits of natural hydrocarbon gases. Hydrogen sulfide and mercaptans are oxidised (P-1) in presence of catalyst with production of elemental sulfur and sulfur dioxide. The received gas is cooled till elemental sulfur is condensed and delivered to tandem layer of adsorbent (A-1), (A-2). At input temperature of the adsorbent is maintained at temperature of 130-150°C and at the output - 100-120°C.

EFFECT: invention allows continuous treatment of gas flows from hydrogen sulfide with variable flow rate and composition.

5 cl, 8 ex, 8 tbl, 2 dwg

Description

The invention relates to the petrochemical and gas industries and can be used in well development in natural hydrocarbon gas fields.

The invention may find application in the purification of associated petroleum gases generated during the extraction and processing of sulphurous oils, in the purification of coke and shale gases, as well as emissions from chemical industries.

Currently, the method of direct heterogeneous-catalytic oxidation of hydrogen sulfide by oxygen to elemental sulfur is used to purify gases from sulfur compounds. Using this method, a high degree of purification of the source gases is achieved at a sufficiently low energy consumption.

A known method of purification of gases from sulfur compounds (RF 2144495, С01В 17/04, B01D 53/48, 01/20/2000), according to which gases are purified from sulfur compounds by their oxidation with oxygen to sulfur and / or disulfides in the oxide catalyst layer with subsequent separation sulfur from purified gas. The catalyst contains 5-100 wt.% Of the active component and is a monolithic block assembled from individual porous elements with through channels, and at least 50% of the pores contained in these elements have a size of 1000 to 5000 Ǻ, and the pore volume is 0 , 15-0.50 cm ³ / g.

The closest in technical essence to the claimed method is a method for producing elemental sulfur from hydrogen sulfide (RF 1627507, С01В 17/04, 15.02.91), based on heterogeneous-catalytic oxidation of hydrogen sulfide, which is carried out in two stages. At the 1st stage, the oxidation is carried out in a fluidized bed of the catalyst at 250-300 ° C, at the 2nd stage - in the reactor with a stationary catalyst bed at 140-155 ° C. The ratio of oxygen to hydrogen sulfide in the 1st stage is 0.5. The method allows you to clean gases containing up to 50 vol.% Hydrogen sulfide, the total degree of conversion of hydrogen sulfide to sulfur reaches 99.99%, while strictly observing the specified ratio of oxygen to hydrogen sulfide in the first stage.

The efficiency of the process of direct oxidation of hydrogen sulfide substantially depends on the stability of the parameters of the initial gas mixture (concentration of hydrogen sulfides and mercaptans, consumption), which leads to the fact that the developed methods of direct oxidation of hydrogen sulfide do not allow a stable residual content of sulfur compounds, the total concentration of which in the purified gas should exceed 20 ppm., which is a regulated requirement.

In this regard, it is necessary to develop combined technologies, including direct oxidation stages, followed by post-treatment to sanitary standards, which implies the development of multifunctional adsorbents that can effectively absorb sulfur compounds of various classes.

The problem solved by the invention is the provision of continuous cleaning of hydrogen sulfide gas streams with a variable flow rate and composition, environmental reliability and process safety.

To solve this problem, a method for purifying gas streams from hydrogen sulfide with a variable flow rate and composition is proposed, including oxidation of hydrogen sulfide and mercaptans with oxygen in the presence of a catalyst to produce elemental sulfur and sulfur dioxide, the gas after the direct oxidation step is cooled to condense elemental sulfur and is fed into a sequentially located layer multifunctional adsorbent.

The temperature of the adsorbent at the inlet is maintained equal to 130-150 ° C, and at the exit is equal to 100-120 ° C.

As an adsorbent, a material is used that contains ferromanganese nodules and has the following composition in terms of oxides, wt.%: Fe ₂ O ₃ 20.0-35.0; MnO ₂ 20.0-35.0; SiO ₂ 10.0-25.0; ZnO 5-10, Al ₂ O ₃ 5.0-10.0; Na ₂ O 2.0-5.0; K ₂ O 1.5-5.0; MgO 1.5-3.0; CaO 1.5-3.0; P ₂ O ₅ 3.0-10.0.

The adsorbent may further comprise a binder. As a binder, it may contain inorganic compounds, such as aluminum hydroxide, magnesium oxide or calcium oxide, in an amount of 15-25, mainly 20 wt.%, In terms of anhydrous substance, as well as inorganic acids in an amount of 3-5 wt. %, calculated on the anhydrous substance. As a binder, it may also contain organic macromolecular compounds in an amount of 4-5 wt.%, In terms of anhydrous substance.

Conceptually, the process of cleaning gas streams from sulfur compounds is described as follows.

Partial oxidation of hydrogen sulfide to elemental sulfur (1) and deep oxidation of light mercaptans with the formation of sulfur dioxide (2) occur in the R-1 reactor during the interaction of sulfur compounds of the gas to be purified with oxygen.

$$H_{2}S+0.5{\mathrm{<figure-callout\; id="2"\; label="O"\; filenames="00000004.png"\; state="\{\{state\}\}">O</figure-callout>}}_2\Rightarrow S_r+H_{2}O+Q\begin{array}{ccc}& & \end{array}\left(\mathrm{one}\right)$$

$$RSH+{\mathrm{<figure-callout\; id="2"\; label="O"\; filenames="00000004.png"\; state="\{\{state\}\}">O</figure-callout>}}_2\Rightarrow \mathrm{<figure-callout\; id="2"\; label="S\; O"\; filenames="00000004.png"\; state="\{\{state\}\}">S\; </figure-callout>}{O}_{}{}_2+C{O}_2+H_{2}O\begin{array}{ccc}& & \end{array}\left(2\right)$$

Due to the fact that the reaction indices 1 (selectivity with respect to sulfur formation) are quite sensitive to the hydrogen sulfide / oxygen ratio, and the parameters of the initial gas mixture (concentration of hydrogen sulfides and mercaptans, flow rate) are usually unstable, it is rather complicated from the point of view of hardware design provide a clear stoichiometric oxygen / hydrogen sulfide ratio.

Thus, if oxygen is in excess, SO ₂ is formed, and with a lack of O ₂ , a breakdown of hydrogen sulfide occurs. As a result, the adsorbent loaded in the apparatus A-1 and A-2 must have multifunctional properties and provide a high adsorption capacity both in respect of hydrogen sulfide and sulfur dioxide.

It is proposed to consider two options for the regeneration of saturated adsorbents:

A) Regeneration by exposure to water vapor. In this case, the preferred product is hydrogen sulfide, the stream of which is mixed with the main stream of the gas to be purified.

B) Oxidative regeneration, when the adsorbent is exposed to atmospheric oxygen at a temperature of 500-600 ° C. In this case, sulfur dioxide is formed, which is sent for reduction utilization to obtain elemental sulfur.

To illustrate the proposed method, we give examples of its implementation.

Studies of the process of oxidation of hydrogen sulfide are carried out in a laboratory setup, a diagram of which is shown in Figure 1.

A feature of the laboratory setup is the possibility of carrying out the direct oxidation of hydrogen sulfide both in a fixed and in a fluidized bed of catalyst granules, which allows to achieve high isothermality of the catalyst layer (maintaining a given process temperature) at hydrogen sulfide concentrations in the feed gas mixture up to 100%.

Figure 1 presents a block diagram of a combined installation with an adsorber and a direct oxidation unit.

Figure 2 presents a diagram of a laboratory setup, where: 1 - a reactor with the possibility of fluidization of the catalyst bed, 2 - a furnace with a fluidized bed of quartz sand, 3 - a trap for liquid sulfur, 4 - adsorber.

Example 1

A gas simulating the actual composition of associated petroleum or natural gas at a pressure of 0.5 atm and air is fed into a laboratory direct oxidation reactor. The total gas mixture consumption is 3.6 dm ³ / h.

1 g of direct oxidation catalyst is charged to the reactor. In the direct oxidation reactor, under optimal conditions established during the experiments on the direct oxidation of sulfur compounds, hydrogen sulfide is oxidized to elemental sulfur, and mercaptan to sulfur dioxide. The vapor-gas mixture enters a cooled trap, where its temperature drops to 150 ° C, the sulfur condenses, and the gas stream enters the adsorber, where 5 g of the adsorbent of the composition are loaded, wt.%: Fe ₂ O ₃ 20.0; MnO ₂ 20.0; SiO ₂ 25.0; ZnO - 6, Al ₂ O ₃ 10.0; Na ₂ O 5.0; K ₂ O 5.0; MgO 3.0; CaO 3.0; P ₂ O ₅ 8.0.

The temperature in the adsorber is maintained at the beginning along the gas 130-150 ° C, at the end 100-120 ° C.

To control the pressure in the system, a valve is installed at the inlet from the adsorber. The gas mixture after the trap and adsorber is fed for analysis to the Crystal 2000 M chromatograph.

The experimental results are shown in table 1.

Table 1 The results of the study of the combined process for the purification of hydrocarbon mixtures (model mixture associated petroleum gas, natural gas, pressure g. - 0.5 ati) The components of the gas mixture,% vol. Gas composition (dry gas) To the reactor
ref. mixture After the reactor
Sampling point No. 1 After adsorber
Sampling point No. 2 100 hours of continuous operation H ₂ s 1,0 <0.01 (80 ppm) <5 ppm RSH 100ppm (0.01%) - - CO ₂ 1,1 1,2 1,2 O ₂ 0.52 0.02 0.02 N ₂ 10.1 10.3 10.3 CH ₄ 80.2 80.9 80.9 C ₂ -C ₅ 7.1 7.25 7.25 SO ₂ - 97 ppm (0.0097%) <5 ppm

Example 2

Similar to example 1, differs in excess pressure, which is 4 ati.

The results are shown in table 2.

table 2 The results of the study of the combined process of cleaning hydrocarbon mixtures (model mixture associated petroleum gas, natural gas, pressure gage - 4 ati) The components of the gas mixture,% vol. Gas composition (dry gas) To the reactor
ref. mixture After the reactor
Sampling point No. 1 After adsorber
Sampling point No. 2 100 hours of continuous operation H ₂ s 1,0 <0.01 (40 ppm) <5 ppm RSH 100 ppm (0.01%) - - CO ₂ 1.1 1,2 1,2 O ₂ 0.52 0.02 0.02 N ₂ 10.1 10.3 10.3 CH ₄ 80.2 80.9 80.9 C ₂ -C ₅ 7.1 7.25 7.25 SO ₂ - 100 ppm (0.01%) <5 ppm

Example 3

Similar to example 1, it differs in that gas simulating the tail gases of the Klaus process or ventilation emissions is supplied to the reactor. The experimental results are shown in table 3.

Table 3 The results of the study of the combined cleaning process of mixtures simulating the tail gases of the Klaus process or ventilation emissions (pressure h. - 0.5 ati) The components of the gas mixture,% vol. Gas composition (dry gas) To the reactor
ref. mixture After the reactor
Sampling point No. 1 After adsorber
Sampling point No. 2 100 hours of continuous operation H ₂ s 0.8 <0.01 (90 ppm) <5 ppm RSH 100ppm (0.01%) - - CO ₂ 5,0 5.0 5.0 O ₂ 0.41 0.01 0,0 N ₂ rest Rest rest SO ₂ -0.1 0.07% <5 ppm

Example 4

Similar to example 1, characterized in that the reactor serves gas simulating coke oven gas.

The experimental results are shown in table 4.

Table 4 The results of the study of the combined cleaning process of mixtures simulating coke oven gas (pressure h. - 0.5 ati) The components of the gas mixture,% vol. Gas composition (dry gas) To the reactor
ref. mixture After the reactor
Sampling point No. 1 After adsorber
Sampling point No. 2 100 hours of continuous operation H ₂ s 0.16 <0.005 (50 ppm) <5 ppm H ₂ 57 57 57 CO ₂ 2.2 2.2 2.2 O ₂ 0.4 0.3 0.3 N ₂ rest rest rest CH ₄ 24 24 24 With 8.0 8.0 8.0 SO ₂ - 120ppm (0.12% vol.) <7ppm

Example 5

Similar to example 1, it differs in that a gas simulating acid gas generated during the amine purification of hydrogen sulfide-containing streams is fed into the reactor.

The experimental results are shown in table 5.

Table 5 The results of the study of the combined process of purification of mixtures simulating acid gases formed during the amine purification of hydrogen sulfide-containing streams (pressure gage - 0.4 ati) The components of the gas mixture,% vol. Gas composition (dry gas) To the reactor
ref. mixture After the reactor Sampling point No. 1 After adsorber
Sampling point No. 2 10 hours of continuous operation H ₂ s fifteen 50 ppm <5 ppm CO ₂ 60 58.85 58.85 O ₂ 8 0.00 0.00 N ₂ rest rest rest CH ₄ one 1.28 24 SO ₂ - 1.28 <10 ppm

Example 6

Similar to example 1, characterized in that the reactor serves gas simulating shale gas

The experimental results are shown in table 6.

Table 6 The results of the study of the combined process for the purification of hydrocarbon mixtures (model mixture is shale gas, pressure h. - 0.5 ati) The components of the gas mixture,% vol. Gas composition (dry gas) To the reactor
ref. mixture After the reactor
Sampling point No. 1 After adsorber
Sampling point No. 2 100 hours of continuous operation H ₂ s 1,0 <0.01 (40ppm) <5 ppm CO ₂ 1,1 1,2 1,2 O ₂ 0.52 0.02 0.02 N ₂ 10.1 10.3 10.3 CH ₄ 80.2 80.9 80.9 C ₂ -C ₅ 7.1 7.25 7.25 SO ₂ - 100 ppm (0.01%) <8 ppm

Example 7

Similar to example 1, differs in the composition of the adsorbent

Use an adsorbent of the following composition, wt.%: Fe ₂ O ₃ 35,0; MnO ₂ 35.0; SiO ₂ 10.0; ZnO 5, Al ₂ O ₃ 5.0; Na ₂ O 2.0; K ₂ O 2.0; MgO 1.5; CaO 1.5; P ₂ O ₅ 3.0. The experimental results are shown in table 7.

Table 7 The results of the study of the combined process for the purification of hydrocarbon mixtures (model mixture associated petroleum gas, natural gas, pressure gage - 0.5 ati). The components of the gas mixture,% vol. Gas composition (dry gas) To the reactor
ref. mixture After the reactor
Sampling point No. 1 After adsorber
Sampling point No. 2 100 hours of continuous operation H ₂ s 1,0 <0.01 (80 ppm) <4 ppm RSH 100 ppm (0.01%) - - CO ₂ 1,1 1,2 1,2 O ₂ 0.52 0.02 0.02 N ₂ 10.1 10.3 10.3 CH ₄ 80.2 80.9 80.9 C ₂ -C ₅ 7.1 7.25 7.25 SO ₂ - 100 ppm (0.01%) <5 ppm

Example 8

Similar to example 1, differs in the composition of the adsorbent. Use an adsorbent of the following composition, wt.%: Fe ₂ O ₃ 25,0; MnO ₂ 25.0; SiO ₂ 15.0; ZnO 9.5; Al ₂ O ₃ 7.5; Na ₂ O 3,5; K ₂ O 3.0; MgO 2.5; CaO 2.0; P ₂ O ₅ 7.0.

The experimental results are shown in table 8.

Table 8 The results of the study of the combined process for the purification of hydrocarbon mixtures (model mixture associated petroleum gas, natural gas, pressure g. - 0.5 ati) The components of the gas mixture,% vol. Gas composition (dry gas) To the reactor
ref. mixture After the reactor
Sampling point No. 1 After adsorber
Sampling point No. 2 100 hours of continuous operation H ₂ s 1,0 <0.01 (80ppm) <8 ppm RSH 100 ppm (0.01%) - - CO ₂ 1,1 1,2 1,2 O ₂ 0.52 0.02 0.02 N ₂ 10.1 10.3 10.3 CH ₄ 80.2 80.9 80.9 C ₂ -C ₅ 7.1 7.25 7.25 SO ₂ - 100 ppm (0.01%) <5 ppm

As can be seen from the presented data, the developed combined method allows purifying model gases of various compositions to the required regulated norms.

Claims (5)

1. A method of purifying gas flows from hydrogen sulfide with a variable flow rate, composition and pressure, including direct oxidation of hydrogen sulfide and mercaptans with oxygen in the presence of a catalyst to produce elemental sulfur and sulfur dioxide, characterized in that the gas after the direct oxidation step is cooled to condense elemental sulfur and serves in a sequentially located adsorbent layer. 2. The method according to claim 1, characterized in that the temperature of the adsorbent at the inlet is maintained equal to 130-150 ° C, and at the exit equal to 100-120 ° C. 3. The method according to claim 1, characterized in that as the adsorbent use a material that contains ferromanganese compositions and has the following composition in terms of oxides, wt.%: Fe ₂ O ₃ 20,0-35,0; MnO ₂ 20.0-35.0; SiO ₂ 10.0-25.0; ZnO 5-10, Al ₂ O ₃ 5.0-10.0; Na ₂ O 2.0-5.0; K ₂ O 1.5-5.0; MgO 1.5-3.0; CaO 1.5-3.0; P ₂ O ₅ 3.0-10.0. 4. The method according to claim 3, characterized in that the adsorbent may further comprise a binder. 5. The method according to claim 1, characterized in that the direct oxidation process is carried out in a fluidized bed of catalyst.

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