The method of decomposition of hydrogen sulfide and/or mercaptans

 

(57) Abstract:

The invention relates to the field of gas and oil, and in particular to methods of decomposition and recycling of hydrogen sulfide and/or mercaptans, and can be used for the production of hydrogen and sulfur from hydrogen sulfide, and also for purification from hydrogen sulfide and mercaptans gas mixtures. The described method of decomposition of hydrogen sulfide and/or mercaptans, comprising passing the hydrogen sulfide and/or mercaptoacetate gas through the layer of solid material capable of decomposing hydrogen sulfide release of hydrogen and/or hydrocarbon gas and the formation of sulfur-containing compounds on the surface of the material. At this stage of the decomposition is carried out in hemosorption-catalytic mode at a temperature below the melting point of sulfur to produce hydrogen and/or hydrocarbons and surface chemisorbing sulfur-containing compounds. The reactivation is carried out at a temperature below the melting point of sulfur, and the regeneration is carried out at a temperature above the melting point of sulfur. The technical result - the decomposition process is carried out at a low temperature, such as a room, there is no need for frequent regeneration rolled, and in particular to methods of decomposition and recycling of hydrogen sulfide and mercaptans (thiols), and can be used for the production of hydrogen and sulfur from hydrogen sulfide, and also for purification from hydrogen sulfide and mercaptans gas mixtures.

Hydrogen sulfide is the main byproduct of oil refining, and hydrometallurgy, in large quantities up to 50 vol.% contained in gas condensate deposits of natural gas is the main product of decomposition of many mineral and organic substances. Simultaneously, hydrogen sulfide is a strong toxic poison, causing poisoning of living organisms. Therefore, the exhaust gases of industrial plants must be thoroughly cleaned from hydrogen sulfide. At the same time, the hydrogen sulfide can be the feedstock for production of valuable chemical product hydrogen.

Mercaptans are byproducts of the decomposition of mineral and organic substances which are present as impurities in the gaseous oil products in large quantities may be present in gas condensate natural gas fields. Mercaptans are toxic substances with a very unpleasant smell, so exhaust gases industry is out as odorants household gases, where they are used for detection of leakage. The presence of mercaptans in hydrocarbon gases leads to deactivation of the catalysts for the conversion of these gases into valuable products, so these gases should also be thoroughly cleaned from mercaptans.

Direct thermal decomposition of hydrogen sulfide into hydrogen and sulfur by the reaction:

H2SH2+S-Q (1)

is a highly endothermic process and can be very noticeable speed to occur only at high temperatures. The known method of thermal decomposition of hydrogen sulfide into hydrogen and sulfur, including the transmission of sulfurous gas through the reaction zone at a temperature 850-1600°C, where the decomposition of H2S to hydrogen and sulfur and subsequent cooling of the specified gas to a temperature of 110-150°C for condensing the formed sulfur (US 4302434, 01 17/04, 24.11.81). The disadvantages of this method are: high temperature required to achieve a high degree of decomposition of hydrogen sulfide; high energy consumption on the implementation of the reaction and the possible compensation of heat losses; the possibility of reducing the degree of decomposition of hydrogen sulfide due to the reverse reaction between hydrogen and sulfur cooling gas; possible in order to ergatis pyrolysis at high temperature; the low efficiency of the process by reducing the concentration of hydrogen sulfide in the hydrogen sulfide-containing source gas; the need to use special expensive structural materials with high temperature resistance for the design of high-temperature reaction zone. Besides, the decomposition reaction of hydrogen sulfide at high temperature leads to the formation of gaseous sulfur consisting of saturated molecules S2. The latter circumstance adversely affect thermodynamics of the whole process, because it is known that obtaining less energy efficient products in the condensed (liquid or solid) state conducive to shift the equilibrium of the reaction towards formation of reaction products.

It is known that catalysts do not affect the displacement of the equilibrium of reaction (1), but their use allows, in some cases, to shift the equilibrium of reaction (1) in the direction of formation of products. One of the known methods demonstrates how the catalytic decomposition of hydrogen sulfide into hydrogen and sulfur, including circulation sulfurous gas through the catalyst bed at a temperature of 450-800°With removal of the formed sulfur of compasses is of decomposition reaction of hydrogen sulfide. The disadvantage of this method is the low equilibrium degree of decomposition of hydrogen sulfide in the specified temperature range of not more than 15%.

There is a method of decomposition of hydrogen sulfide into hydrogen and sulfur, including periodic transmission of sulfurous gas through the bed of sorbent, containing sulfides of iron, cobalt or Nickel, at a temperature 258-536°C, which alternated with periodic heating the sorbent to a temperature of about 700°C for regeneration (US 2979384, 423/573, 01.04.61). During the transmission of sulfurous gas specified components of the sorbent interact with the hydrogen sulfide with the formation of gaseous hydrogen and solid polysulfides of these metals. During regeneration of the sorbent is thermal decomposition of these polysulfides with the formation of the original sulfides and elemental sulfur vapor. The advantage of this method is the possibility of achieving a high degree of decomposition of hydrogen sulfide. The disadvantage of this method is the relatively high temperature decomposition of hydrogen sulfide, a further reduction which is limited by low flow velocity, these chemical reactions at low temperature, and high-Chu (1) by a new route, that can significantly lower the temperature of reaction (1). It is this feature incorporated in this invention. In this case, the technical effect of the developed method consists in the combination of the paired hemosorption-catalytic decomposition of hydrogen sulfide and/or mercaptans on the catalyst surface at a temperature below the melting point of sulfur, followed by periodic removal of sulfur from the catalyst surface at a temperature above its melting point. The developed method allows to reduce the temperature hemosorption-catalytic stage below the melting point of sulfur (110-120°C), and the decrease in temperature favors the increase in the degree of surface coating dissociatively hammarbyhamnen hydrogen sulfide, and, consequently, increases the capacity of the catalyst with respect to adsorbed hydrogen sulphide. In addition, thermodynamic effect is achieved by the sulfur in the condensed state, thus substantially lowering the temperature of the regeneration of the catalyst above 110°C, but below 350°C and condensation of solid sulfur. Similarly, the process of decomposition of mercaptans. This allows you to simplify the process and reduce the cost of equipment is no possibility of recycling the hydrogen sulfide and mercaptoundecanoic gases without prior concentration of H2S and mercaptans, as well as without the removal of hydrocarbons and other impurities.

The method is as follows.

Hydrogen sulfide and/or mercaptoacetate gas with an initial temperature below the melting point of sulfur is passed through the layer of the solid catalyst with the ability to dissociatively chemosensitivity hydrogen sulfide and/or mercaptan in this temperature region. When this is coupled chemisorption of hydrogen sulfide and/or mercaptan with the formation of gaseous hydrogen and/or hydrocarbon and solid sulfur-containing products chemisorption on the surface of the solid catalyst. Exiting the solid catalyst, the hydrogen and/or hydrocarbon gas is directed to the selection of product hydrogen or hydrocarbon, or use any other method. As you fill the chemisorption capacity of the catalyst and the appearance of hydrogen sulfide or mercaptan in the gas phase at the outlet of the layer of the solid catalyst, passing the gas through a layer of solid catalyst cease and begin to pass through the layer reactivating gas not containing hydrogen sulfide, or containing a concentration not exceeding its concentration is of sulfur 110-120°C therefore, sulfur is not removed from the catalyst surface, but condenses on the catalyst surface, freeing the catalytically active centers. Thus, there is a reactivation of the catalyst. Then again serves the source gas, after filling the surface of the catalyst hammarbyhamnen hydrogen sulfide and/or mercaptan begin again to skip reactivating gas at a temperature below the melting point of sulfur, thus there is an accumulation of solid sulfur on the catalyst surface. This cycle chemisorption - reactivation of the catalyst is continued repeatedly without changing the chemisorption capacity of the catalyst, with solid sulfur accumulates on the catalyst surface in an amount up to 50-100 wt.%. After solid sulfur will block the active centers of the catalyst, the temperature of regeneration is increased to a temperature above the melting point of sulfur, liquid sulfur flows from the catalyst surface and condenses in the condenser, located directly behind the layer of catalyst. Thus, the regeneration of the catalyst. Cycle processes chemisorption - reactivation - the regeneration is carried out repeatedly without changing the chemisorption capacity and the activity of the catalyst. If it is conduct in parallel in at least two layers of the solid catalyst, each of which alternately alternate modes of transmission source gas, revitalizing and regenerating gas.

One of the options for the implementation of the developed method is contacting sulfurous and/or mercaptoacetate gas with a catalyst in a confined space with the circulation of the gas phase, or without it. Similarly, the reactivation of the catalyst can be carried out in a confined space with a circulation of gas through the layer of chemical sorbent - catalyst, or without it. Similarly, stage catalyst regeneration can also be carried out in a confined space with a circulation of gas through the layer of chemical sorbent - catalyst, or without it.

The main advantage of the proposed method is the possibility of decomposition of hydrogen sulfide and/or mercaptans at a low temperature, e.g. room temperature and below, with the resulting sulfur accumulates on the catalyst surface, but not by disabling the active component of the catalyst. As the surface coverage of the catalyst solid gray to such a level, when it comes to blocking of the active component of solid sulfur, the catalyst is heated in the atmosphere of the regenerating gas to tempera is instore, located directly behind the catalytic zone. Thus, freed the surface of the catalyst and the regeneration of the active component.

The invention is illustrated by the following examples.

Example 1. Processing is subjected to natural gas containing 3 vol.% of hydrogen sulfide, and nitrogen, carbon dioxide and water vapor. The specified gas is passed at a temperature of 25°With through a layer of granular graphite-like carbon material obtained by a known method (US 4978649, C 01 31/10, 18.12.90). Leaving a layer of the specified material gas contains hydrogen at a concentration of up to 3 vol.%, as well as nitrogen, carbon dioxide and water vapor, hydrogen sulfide is absent. After 45 min after the start of transmission of sulfurous gas when exiting a specified catalyst gas begins to decrease the concentration of hydrogen, and unreacted hydrogen sulfide, cease transmission of sulfurous gas and start the transmission of reactivating gas containing nitrogen, methane and carbon dioxide with a temperature of 40°C. the Reactivation finish after 30 min, the catalyst was cooled to room temperature and again submit the original servodio is another advantage of hydrogen sulfide, therefore, the gas supply is stopped. Through the catalyst begin to pass the reactivating gas at a temperature of 40°C, after 30 min reactivation stop and begin again to submit the original hydrogen sulfide-containing gas at room temperature. The capacity of the catalyst to hydrogen sulfide does not change. This procedure chemisorption - reactivation continue repeatedly without reducing the capacity of the catalyst to hydrogen sulfide. After accumulation on the catalyst surface of solid sulfur in the amount of more than 20 wt.%, the capacity of the catalyst to hydrogen sulfide begins to decrease, therefore, carry out the procedure for catalyst regeneration. For this purpose through the catalyst bed begin to pass the reactivating gas at a temperature of 150°With liquid sulfur flows from the catalyst surface and condenses in the condenser, located directly behind the layer of catalyst and cooled to room temperature. Passing a regenerating gas is carried out for 30 minutes, after which it re-produce the transmission of sulfurous gas and so on.

Example 2. Processing is subjected to a gas containing 5 vol.% of hydrogen sulfide, and nitrogen, oxygen and a mixture of light hydrocarbons. The specified gas is passed PR who holds the hydrogen in an amount of 5 vol.%, as well as nitrogen, oxygen and a mixture of light hydrocarbons, hydrogen sulfide is absent. After 40 min after the start of transmission of sulfurous gas at the outlet of the layer of this material appears sulfide, therefore, the supply of the source gas stop and start feeding reactivating gas is nitrogen at a temperature of 50°C. After 20 min reactivation finish and begin again to submit the original hydrogen sulfide-containing gas at 0°C. Cycles chemisorption - reactivation repeat repeatedly to fill the surface of the molybdenum disulfide solid grey. Then through a layer of specified material serves regenerating gas is nitrogen at a temperature of 175°C, liquid sulfur flows from the catalyst surface and condenses in the condenser, located directly after the catalytic layer and cooled to 0°C. the Regeneration is carried out for 15 min, then through a layer of specified material resumed the supply of the source gas mixture containing hydrogen sulfide. This cycle hemosorption-catalytic decomposition of hydrogen sulfide - reactivation of the solid catalyst - regeneration of the catalyst with sulfur condensation in the condenser, located directly behind the catalytic zone, carry out mnogokriterial 3. Processing is subjected to natural gas, containing 40 vol.% of hydrogen sulfide. The specified gas is passed through the layer hemosorption-catalytic material is a sulfide of cobalt CoxSyat a temperature of -5°C. Exiting sulfide catalyst natural gas contains up to 40% vol. hydrogen sulfide is absent. After 20 min after the start of transmission of the specified gas at the outlet of the layer of sulfide catalyst begins to decrease the concentration of hydrogen and appears sulfide, therefore, the transmission source gas stop and isolate the reaction volume by known methods. After that begin to circulate the gas phase through the catalyst bed at a temperature of 45°C. After 40 min reactivation finish and begin again to submit the original hydrogen sulfide-containing gas at a temperature of -5°C. Cycles chemisorption - reactivation repeat repeatedly to fill the surface of the catalyst solid grey. Then through a layer of the specified catalyst serves regenerating gas is nitrogen at a temperature of 190°C, liquid sulfur flows from the catalyst surface and condenses in the condenser, located directly after the catalytic layer and cooled to 0°C. After 10 min after the beginning of Rashi gas. The process is carried out in periodic mode repeatedly without reducing the 100% conversion of hydrogen sulfide and without reducing the chemisorption capacity of the catalyst.

Example 4. Processing is subjected to gas consisting of a mixture of synthesis gas (CO+H2) and 0.1% vol. of hydrogen sulfide. The specified gas is passed through a layer of sulfide catalyst composition of COxMOySzcooled to -10°C. At the exit from the layer specified recyclable material gas contains CO and hydrogen, hydrogen sulfide is absent. After 45 min after the start of transmission in the outgoing gas appears sulfide, therefore, the supply of the source gas stop and start feeding reactivating gas is nitrogen at a temperature of 60°C. After 20 min reactivation finish and begin again to submit the original gas mixture at a temperature of -10°C. Cycles chemisorption - reactivation repeat repeatedly to fill the surface of the catalyst solid grey. Then a layer of the specified catalyst is isolated and heated at a temperature of 120°C, liquid sulfur flows from the catalyst surface and condenses in the condenser, located directly after the catalytic layer and cooled to 0°C. After 50 min after the start of regeneration of the catalyst the reduction 100% conversion of hydrogen sulfide and without reducing the chemisorption capacity of the catalyst.

Example 5. Processing is subjected to gas consisting of a mixture of 90 vol.% nitrogen and 10% vol. of hydrogen sulfide. The specified gas is passed through the layer hemosorption-catalytic material is porous Nickel metal, cooled to -20°C. At the exit from the layer specified recyclable material gas contains nitrogen and hydrogen, the hydrogen sulfide is absent. After 100 min after the start of transmission in the outgoing gas appears sulfide, therefore, the supply of the source gas stop and start feeding reactivating gas is hydrogen at a temperature of 60°C. After 20 min reactivation finish and begin again to submit the original gas mixture at a temperature of -20°C. Cycles chemisorption - reactivation repeat repeatedly to fill the surface of the catalyst solid grey. Then through a layer of the specified catalyst serves regenerating gas is nitrogen at a temperature of 300°C, liquid sulfur flows from the catalyst surface and condenses in the condenser, located directly after the catalytic layer and cooled to 0°C. After 50 min after the start of regeneration of the catalyst, the flow of regenerating gas stop and re serves the original hydrogen sulfide-containing gas at a temperature of -20°C. the Process Provo is evident capacity of the catalyst.

Example 6. Processing is subjected to gas consisting of a mixture of oxygen and 0.01 vol.% of hydrogen sulfide. The specified gas is passed through the layer hemosorption-catalytic material is porous bored Nickel, cooled to 20°C. At the exit from the layer specified recyclable material gas contains oxygen and hydrogen, the hydrogen sulfide is absent. After 10 min after the start of transmission in the outgoing gas appears sulfide, therefore, the supply of the source gas stop and start feeding reactivating gas is nitrogen at a temperature of 60°C. After 20 min reactivation finish and begin again to submit the original gas mixture at a temperature of 20°C. Cycles chemisorption - reactivation repeat repeatedly to fill the surface of the catalyst solid grey. Then through a layer of the specified catalyst serves regenerating gas is nitrogen at a temperature of 140°C, liquid sulfur flows from the catalyst surface and condenses in the condenser, located directly after the catalytic layer and cooled to 0°C. After 20 min after the start of regeneration of the catalyst, the flow of regenerating gas stop and re serves the original hydrogen sulfide-containing gas. The process is carried out in periodic mode a lot of the LASS="ptx2"> Example 7. Processing is subjected to a natural gas containing methane, 5% vol. hydrogen sulfide and 0.3 vol.% the mercaptan (methanethiol). The specified gas is passed at room temperature through a layer of sulfide catalyst composition of CoxMoySzdeposited on a porous carrier is alumina. The output from the layer specified recyclable material gas contains methane and hydrogen, hydrogen sulfide and methyl mercaptan are missing. After 90 min after the start of transmission in the outgoing gas appear sulfide and methylmercaptan, therefore, the supply of the source gas stop and start feeding reactivating gas is nitrogen at a temperature of 50°C. After 20 min reactivation finish and begin again to submit the original gas mixture at room temperature. Cycles chemisorption - reactivation repeat repeatedly to fill the surface of the catalyst solid grey. Then a layer of the specified catalyst is isolated and heated at a temperature of 120°C, liquid sulfur flows from the catalyst surface and condenses in the condenser, located directly after the catalytic layer and cooled to 0°C. After 50 min after the start of regeneration of the catalyst is recycled to the original sulfide and netelmer odorata and without reducing the chemisorption capacity of the catalyst.

Example 8. Processing is subjected to a gas containing ethane and 5% vol. ethyl mercaptan (ethandiol). The specified gas is passed at room temperature through a layer of sulfide catalyst composition NixMOySzdeposited on a porous carrier is silica gel. The output from the layer specified recyclable material gas contains ethane, ethyl mercaptan is missing. After 90 min after the start of transmission in the outgoing gas appear ethyl mercaptan, therefore, the supply of the source gas stop and start feeding reactivating gas is nitrogen at a temperature of 60°C. After 30 min reactivation finish and begin again to submit the original gas mixture at room temperature. Cycles chemisorption - reactivation repeat repeatedly to fill the surface of the catalyst solid grey. Then a layer of the specified catalyst is isolated and heated at a temperature of 120°C, liquid sulfur flows from the catalyst surface and condenses in the condenser, located directly after the catalytic layer and cooled to 0°C. After 50 min after the start of regeneration of the catalyst is recycled source ethane and ethyl mercaptan. The process is carried out in periodic mode repeatedly without reducing 100% of the AK seen from the above examples, the proposed method allows the decomposition of hydrogen sulfide and/or mercaptans at a low temperature, e.g. room, there is no need for frequent regeneration of the catalyst after each stage chemisorption.

The method of decomposition of hydrogen sulfide and/or mercaptans comprising contacting the hydrogen sulfide - and/or mercaptoacetate gas through the layer of solid material capable of decomposing hydrogen sulfide and/or mercaptan release of hydrogen and/or hydrocarbon gas and the formation of sulfur-containing compounds on the surface of the material, periodic regeneration of the material by decomposition of these sulfur-containing compounds and sulphur separation, characterized in that the stage of decomposition is carried out in hemosorption-catalytic mode at a temperature below the melting point of sulfur to produce hydrogen and/or hydrocarbon gas and surface chemisorbing sulfur-containing compounds, the reactivation is carried out at a temperature below the melting point of sulfur, and regeneration is carried out at a temperature above the melting point of sulfur.



 

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