The present invention relates to the disciplinary field of chemistry and physics materials. Because the objective of the present invention is to describe the removal of H2S by using nanoparticles of nanometer-sized ferrites and synthesized by the modified chemical co-precipitation method. The removal is carried out of gas containing high concentrations of H2S and is developed by continuous flow in a reactor and at room temperature.
CH4 has a greenhouse effect 21 times greater than CO2 in the atmosphere, which makes it preferable to use its energy power and emit CO2 into the environment from its combustion. An attached problem in the production and use of biogas is hydrogen sulfide (H2S) present in the gas mixture. H2S is produced naturally during the reduction of sulfate and sulfur-containing organic compounds, it is associated with the metabolism of anaerobic bacteria and archaea. H2S is an unwanted compound in biogas as it generates corrosion and wear in combustion engines, which results in high maintenance costs. Various minerals have been tested for desulfurization of biogas in situ, adding them in anaerobic reactors, such as iron ores (magnetite, magemite, hematite), at a dose of 5 g in 250 ml of an experimental reactor.
The addition of these minerals in larger reactors could promote the production of higher quality biogas. The most used systems to treat the gas mixture, coming from the bioreactor, are adsorption systems based on beds of activated carbon and metal oxides; Adsorption in iron oxides is a viable alternative in the removal of H2S in biogas, removal efficiencies of up to 99% have been reported, in addition to its low cost. In terms of removal, there is a direct relationship between the amount of H2S removed and the surface area of the adsorbent material. However, conventional iron oxides have the limitation that their surface area hardly exceeds 82 m2 g−1.
There are patents that talk about the modification of the surface area by different methods, some of them are mentioned below:
EP87856A1 discusses the removal of H2S normally present in gas by means of an absorbent solution containing amino groups and is selective for H2S where the gas also contains CO2. In the process of removal, it is carried out in a tower that is capable of removing CO2 and H2S in some conditions.
In patent EP0962147A1 he describes a method to generate a substance based on regenerated and submerged cellulose to generate a coagulate that can be regenerated when subjected to baths in stages or heating by means of tubes that carry bituminous carbon to react in an intermediate zone and that treats CO2 and H2S emissions.
US2005003515 talks about a system for removing H2S from methane which includes at least one cartridge-type biofilter that works to sustain microbial activity by consuming H2S contained in methane gas. The H2S contained in methane is transported directly to the biofilter and which contains at least one cartridge containing microorganisms and whose function is to biodegrade the H2S. Then the treated methane is recirculated and stored in a reservoir for later use.
Patent U.S. Pat. No. 4,532,117 talks about a method to remove H2S using a regenerable accusation system capable of absorbing H2S and converting to elemental sulfur, this is provided to recondition contaminated systems with the feeding of bacteria and keeps the system sustainably free of bacteria. The aqueous solution is regenerated with aliphatic acid.
Patent CN103706230A talks about a method for removing H2S from geothermal steam under vacuum. A thin curtain of water-acrolein drops is atomized while the geothermal vapor is condensed in an approximate amount of 2:1 in molar ratio of acrolein and H2S.
The removal range is approximately 0.1 ppm to 500 ppm H2S. The acrolein allows to react with the H2S gas in a non-volatile way and is directed to a tower to be cooled and the compound separated.
The 20090188164 patent relates to a method for removing H2S from an acid gas mixture, and reacts with a metal oxide where the gas reacts with the valence state of the metal in a reactor containing an aqueous solution. A REDOX electrochemical reaction is carried out including the compound in a reduced state for subsequent regeneration between an anode and a cathode.
Patent AU1994059391 talks about the removal of H2S and S in liquid oil by adding soluble oil of a composition with alkyl groups containing 7 to 22 carbon in its structure.
U.S. Pat. No. 5,700,438 describes a process for removing H2S and mercaptans from steam, the process is carried out by contacting an aqueous solution containing copper and a group of water-insoluble amines with copper sulfate and which can be regenerated. Copper sulfate is removed from the system and recovered. Finally, another water-soluble copper compound is generated.
U.S. Pat. No. 4,537,753 describes the removal of CO2 and H2S from natural gases by means of an absorption process with a temperature range of 40-100° C. and containing 20 to 70% by weight of methyl groups. H2S is removed from the bottom of the column and then regenerated to be used in another absorption stage.
U.S. Pat. No. 3,205,164 relates the process of removing H2S from hydrocarbons by the reaction t absorption in an alkyl amine and which is capable of being recycled.
U.S. Pat. No. 3,435,590 shows a process for removing H2S and CO2 as a mixture at low temperature. Liquid polypropylene carbonate, acetone or alcohol is used. Some of these reagents or in mixture are applied to absorb H2S and CO2 and then release hot H2. The residual gases are removed by a bath where a boiling process is generated.
U.S. Pat. No. 5,096,589 describes a method for treating water containing H2S, the system includes demineralized water to remove mineral impurities. The demineralized water is then treated with chlorine to convert the H2S into hydrochloric acid and sulfuric acid water while the pH is changed. The water is then neutralized with sodium hydroxide.
U.S. Pat. No. 5,738,834 details the removal of H2S from gas vapor contained in natural gas. It contacts a non-aqueous substance which reacts the H2S to generate elemental sulfur, then an organic base is used to promote the reactions. H2S is sipped in the liquid and then reacts with a sulfate to form other molecules. Cooling is performed to obtain sulfide crystals that are easily separated.
U.S. Pat. No. 5,976,373 relates how the treatment of anaerobic systems and other contaminants is carried out. The chemical equation reaches the reaction of H2S with oxygen until elemental sulfur is formed. A filter is used to remove solids and drag liquid and solids towards an oxygen-rich flow, the flow is directed to a bed of activated carbon where a reaction occurs.
U.S. Pat. No. 6,881,389 B2 explains the process for removing H2S and CO2 from natural gas through contact with seawater. A set of stages where a gas washing is performed is described, each stage has a loss of pressure.
U.S. Pat. No. 8,404,031 B1 describes the removal of H2S and describes the manufacturing process of the system. The material captures the iron to be solubilized with hydrochloric acid. The resulting solution is treated with a caustic soda solution to increase the pH and then neutralized.
The characteristic details of the removal process from nanometric ferrites are presented in the description of the figures; the nanoparticles used are MnxFe3-xO4 Manganese Ferrite with x=0%, 0.1%, 0.3% and 0.5%.; the average size of the nanoparticles is 10 nm; the surface area of the nanoparticles used is 142 to 240 m2/gr; the density of the material is 6,700 to 9,700 kg/m3.
In order to fully appreciate the entire process, I will allow myself to present a brief description. Based on the figures presented, the invention refers to the H2S removal process by using nanometric ferrites obtained at temperatures below 100° C. The process of obtaining the nanoparticles is through the modified process of chemical co-precipitation where the speed of agitation in the mixture of the chlorides used for the precipitation of ferrites is varied. The speed variation is in a range of 20,000 to 48,000 RPM. After obtaining the material, it should be washed until a pH in the range of 7-8 is reached, and then dried for 3 days at a temperature of 70° C.
The synthesis of the ferrite nanoparticles with high surface area is carried out by a chemical method, with the help of a high RPM device and with a constant heating system.
Said method of
In order to specify some results, he following results are presented, but not limited to, the following results,
The graph of
Number | Date | Country | Kind |
---|---|---|---|
MX/A/2017/002349 | Feb 2017 | MX | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/MX2018/000014 | 2/19/2018 | WO | 00 |