Download or read book Hydrogen Sulfide Decomposition to Hydrogen Via a Sulfur Looping Scheme written by Kalyani Vijay Jangam and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogen sulfide (H2S) is a hazardous pollutant, primarily formed during the processing of crude fossil fuels. Considering the detrimental effects of H2S, it is imperative to decompose it into harmless products. The state-of-the-art Claus process enables elemental sulfur recovery from H2S but converts H-content into low-value product- steam instead of valuable hydrogen (H2) due to its oxidative chemistry route. In this research work, H2S decomposition into H2 and elemental sulfur is explored using a sulfur looping scheme through two sub-steps—sulfidation and regeneration. The commercially viable H2 production from H2S demands superior H2S conversion and a sulfur carrier design exhibiting good reactivity and recyclability at minimal energy consumption. Additionally, understanding H2S decomposition reaction mechanism at the molecular scale as well as system level investigations are crucial for the material optimization and process design. The research work presented in the thesis thus focuses on the sulfur carrier design and process development which are investigated from both the fundamental and commercial aspects to meet these requirements. Chapter 2 focuses on the development of iron sulfide (FeS)-based sulfur carriers wherein the inherent low reactivity of FeS towards H2S decomposition is modified through dopant incorporation. A low concentration (2%) dopant addition is found to cause a dramatic reactivity improvement without much increase in material cost while preserving the phase integrity of FeS. The reaction pathways and electronic structures are analyzed using density functional theory to understand the role of dopants towards reactivity improvement. Additionally, a preliminary strategy is proposed for potential dopant selection through experimental and theoretical techniques. In Chapter 3, an innovative approach with nickel sulfide (Ni3S2)-based sulfur carriers utilizing CO2 for its regeneration is explored to reduce the overall energy footprint of the H2S decomposition scheme. Ni3S2 is impregnated on highly stable supports to tackle its thermal instability and enhance the active material dispersion. The synergistic effect of Ni3S2 and support towards H2S decomposition is unraveled through experiments and density functional theory calculations and general guidelines for effective support selection are established for a high-performance carrier design. Chapter 4 delves into analyzing this Ni3S2-based sulfur looping scheme from thermodynamic and reaction kinetic perspectives. The optimum reaction conditions are determined for fixed bed operation of the scheme. Moreover, system level investigations are performed to establish the advantages of the scheme over the Claus process in terms of energy and exergy efficiencies. Chapter 5 aims to enhance the reactivity of supported Ni3S2-based sulfur carrier through the carrier modification using a low concentration Titanium dopant. The reactivity and recyclability improvements are successfully substantiated using thermogravimetric experiments and solid characterization analysis. Thus, this research work provides new insights aiding the design of a robust and efficient sulfur carrier and demonstrates different innovative strategies for H2S upgradation into H2.

Download or read book Energy and Exergy Analysis of Chemical Looping Systems for Hydrogen and Sulfur Recovery written by Sharath Reddy and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fossil fuel power plants often generate sulfur species such as hydrogen sulfide or sulfur dioxide due to the sulfur content of the raw feedstocks. To combat the associated environmental, processing, and corrosion issues, facilities commonly utilize a Claus process to convert hydrogen sulfide to elemental sulfur and water. Unfortunately, the Claus process suffers in efficiency from a thermal oxidation, or combustion, step and high equilibrium reaction temperatures. In this work, two different chemical looping process configurations towards recovering sulfur and H2 are investigated: (1) 3 reactor system (SR) for sulfur recovery; (2) 2 reactor system (SHR) for sulfur and H2 recovery. Since, H2 yield and sulfur recovery in a single thermal decomposition reactor in the SHR system is limited by low H2S equilibrium conversion, a staged H2 separation approach is used to increase H2S conversion to H2 using a staged separation methodology. Steady-state simulations and optimization of process conditions are conducted in Aspen Plus v10 simulation software for the chemical looping process configurations and the Claus process. An energy and exergy analysis is done for the chemical looping and Claus processes to demonstrate the relative contribution to exergy destruction from different unit operations as well as overall exergy and energy efficiency. The two chemical looping process configurations are compared against the Claus process for similar sulfur recovery in a 629 MW integrated combined cycle gasification power plant. The SHR system is found to be the most attractive option due to a 97.11% exergy efficiency with 99.31% H2 recovery. The overall energy and exergy efficiencies of this chemical looping system are 14.74% and 21.54% points higher than the Claus process, respectively, suggesting more efficient use of total input energy.

Download or read book Hydrogen Sulfide Decomposition Into Hydrogen and Sulfur by Quinone Cycles written by M. A. Plummer and published by . This book was released on 1993 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The HYSULF process decomposes hydrogen sulfide using mild conditions. In this process, hydrogen sulfide is first reacted with a quinone in an organic solvent to produce sulfur and hydroquinone. After sulfur removal, hydroquinone is catalytically processed to recover hydrogen and recycle quinone-solvent. The produced sulfur is of excellent quality and easily recoverable from the solvent. The organic solvent should eliminate corrosion problems associated with commercial aqueous redox systems which produce only sulfur. Since air oxidation is used, the sulfite-sulfate salt problems of aqueous systems will be avoided. The purpose of this GRI contract was to develop a better mechanistic understanding of process chemical reactions and economics. This was to result ina) Increased quinone conversion and sulfur precipitation rates; b) Determining the effect of carbon dioxide on first stage chemistry; c) Eliminating the anthrone by-product produced in the dehydrogenation step. Essentially, all the objectives of the project were completed. This report covers the non-confidential work performed at the Colorado School of Mines. Additional results obtained by Marathon are and will remain proprietary unless written permission is obtained from Marathon.

Download or read book Hydrogen Sulfide Generation by Reaction of Natural Gas Sulfur and Steam written by Stanley R. Crane and published by . This book was released on 1981 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Production of Hydrogen by Superadiabatic Decomposition of Hydrogen Sulfide Final Technical Report for the Period June 1 1999 September 30 2000 written by and published by . This book was released on 2000 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this program is to develop an economical process for hydrogen production, with no additional carbon dioxide emission, through the thermal decomposition of hydrogen sulfide (H2S) in H2S-rich waste streams to high-purity hydrogen and elemental sulfur. The novel feature of the process being developed is the superadiabatic combustion (SAC) of part of the H2S in the waste stream to provide the thermal energy required for the decomposition reaction such that no additional energy is required. The program is divided into two phases. In Phase 1, detailed thermochemical and kinetic modeling of the SAC reactor with H2S-rich fuel gas and air/enriched air feeds is undertaken to evaluate the effects of operating conditions on exit gas products and conversion efficiency, and to identify key process parameters. Preliminary modeling results are used as a basis to conduct a thorough evaluation of SAC process design options, including reactor configuration, operating conditions, and productivity-product separation schemes, with respect to potential product yields, thermal efficiency, capital and operating costs, and reliability, ultimately leading to the preparation of a design package and cost estimate for a bench-scale reactor testing system to be assembled and tested in Phase 2 of the program. A detailed parametric testing plan was also developed for process design optimization and model verification in Phase 2. During Phase 2 of this program, IGT, UIC, and industry advisors UOP and BP Amoco will validate the SAC concept through construction of the bench-scale unit and parametric testing. The computer model developed in Phase 1 will be updated with the experimental data and used in future scale-up efforts. The process design will be refined and the cost estimate updated. Market survey and assessment will continue so that a commercial demonstration project can be identified.

Download or read book The Decomposition of Hydrogen Sulphide written by Charles Francis Pickett and published by . This book was released on 1927 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Decomposition of Hydrogen Sulfide in an Electrical Discharge written by Larry A. Haas and published by . This book was released on 1973 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Development of Processes for the Recovery of Sulfur from Acid Gases Part 1 Development of a High temperature Process for Removal of H2S from Coal Gas Using Limestone Thermodynamic and Kinetic Considerations Part 2 Development of a Zero emissions Process for Recovery of Sulfur from Acid Gas Streams written by and published by . This book was released on 1993 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Limestone can be used more effectively as a sorbent for H2S in high-temperature gas-cleaning applications if it is prevented from undergoing calcination. Sorption of H2S by limestone is impeded by sintering of the product CaS layer. Sintering of CaS is catalyzed by CO2, but is not affected by N2 or H2. The kinetics of CaS sintering was determined for the temperature range 750--900°C. When hydrogen sulfide is heated above 600°C in the presence of carbon dioxide elemental sulfur is formed. The rate-limiting step of elemental sulfur formation is thermal decomposition of H2S. Part of the hydrogen thereby produced reacts with CO2, forming CO via the water-gas-shift reaction. The equilibrium of H2S decomposition is therefore shifted to favor the formation of elemental sulfur. The main byproduct is COS, formed by a reaction between CO2 and H2S that is analogous to the water-gas-shift reaction. Smaller amounts of SO2 and CS2 also form. Molybdenum disulfide is a strong catalyst for H2S decomposition in the presence of CO2. A process for recovery of sulfur from H2S using this chemistry is as follows: Hydrogen sulfide is heated in a high-temperature reactor in the presence of CO2 and a suitable catalyst. The primary products of the overall reaction are S2, CO, H2 and H2O. Rapid quenching of the reaction mixture to roughly 600°C prevents loss Of S2 during cooling. Carbonyl sulfide is removed from the product gas by hydrolysis back to CO2 and H2S. Unreacted CO2 and H2S are removed from the product gas and recycled to the reactor, leaving a gas consisting chiefly of H2 and CO, which recovers the hydrogen value from the H2S. This process is economically favorable compared to the existing sulfur-recovery technology and allows emissions of sulfur-containing gases to be controlled to very low levels.

Download or read book Advances in Hydrogen Sulfide Research and Application 2011 Edition written by and published by ScholarlyEditions. This book was released on 2012-01-09 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Hydrogen Sulfide Research and Application: 2011 Edition is a ScholarlyBrief™ that delivers timely, authoritative, comprehensive, and specialized information about Hydrogen Sulfide in a concise format. The editors have built Advances in Hydrogen Sulfide Research and Application: 2011 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Hydrogen Sulfide in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Advances in Hydrogen Sulfide Research and Application: 2011 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.

Download or read book Decomposition of Hydrogen Sulfide and Methane in Pulsed Corona Discharge Reactors written by Sanil John and published by . This book was released on 2008 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Natural gas typically contains 70-90% methane (CH4) and 0-5% hydrogen sulfide (H2S). The conversion of CH4 to hydrogen and more valuable unsaturated higher hydrocarbons is of great importance to the petrochemical industry. Direct decomposition of H2S to yield hydrogen and sulfur would be more beneficial than the conventional Claus process which converts H2S into sulfur and water. CH4 and H2S have been separately decomposed in our experiments with a wire-in-tube pulsed corona discharge reactor. The pulsed corona discharge is a good source for generating chemically active species at room temperature, which initiate chemical reactions leading to CH4 and H2S conversion. The effect of capacitance, cathode material, gas flow rate, and specific energy input on conversion, energy efficiency, and product selectivity in the CH4 decomposition process was studied. Ethane and acetylene appear to be formed from dimerization of CH3 radicals and CH radicals, respectively, while ethylene is formed mainly from the dehydrogenation of ethane. Platinum coated stainless steel cathodes slightly enhance CH4 conversion relative to stainless steel cathodes, perhaps due to a weak catalytic effect. As specific energy input increases, energy efficiency for CH4 conversion goes through a minimum, while the selectivity of acetylene has a maximum value. Comparison of CH4 conversion for different types of plasma reactors shows that the pulsed corona discharge reactors may provide an attractive alternative method for low temperature CH4 conversion. H2S was diluted with one of the four balance gases (Ar, He, N2 and H2) to initiate a corona discharge in our reactor. Breakdown voltages are proportional to the partial pressure of H2S and balance gas. H2S conversion rates and energy efficiencies depend on the balance gas and inlet H2S concentrations. H2S conversion in atomic balance gases like Ar and He is more efficient than that in diatomic balance gases like N2 and H2. H2S decomposition in a novel pulsed corona wire-in-tube reactor with quartz view-ports allowed visual observation of the effect of charge voltage and gas composition on the corona distribution. The H2S conversion and energy efficiency of H2S decomposition varied at constant power due to the selected values of the electrical parameters of pulse forming capacitance, charge voltage, and pulse frequency. Low pulse forming capacitance, low charge voltage, and high pulse frequency operation produce the highest energy efficiency for H2S conversion at constant power. H2S conversion is more efficient in Ar-N2 gas mixture than in Ar or N2. These results can be explained by corona discharge observations, the electron attachment reactions of H2S at the streamer energies and the proposed reaction mechanism of H2S dissociation. The lowest energy consumption for H2S decomposition in a plasma reactor at non-vacuum pressures was obtained in an equimolar mixture of Ar and N2 at the lowest value of pulse forming capacitance. The results reveal the potential for energy efficient H2S decomposition in pulsed corona discharge reactors.

Download or read book Hydrogen Sulfide Removal from Hot Gas and Concentration to Sulfur Using Electrochemistry written by Jack Winnick and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Detailed Analysis of the Hydrogen Sulfide Production Step in a Sulfur sulfur Thermochemical Water Splitting Cycle written by Kevin R. Caple and published by . This book was released on 2014 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: The production of hydrogen has been one of the most heavily studied, energy related fields over the past half century, yet few methods are commercially or economically viable and none are currently sustainable. Of those aiming at the sustainable production of hydrogen using renewable resources, perhaps the most widely studied are those attempting to thermochemically split water via various chemical intermediates. These provide an attractive conceptual alternative to other methods due to lower energy input requirements and to the production of the targeted hydrogen and oxygen in separate reaction steps. One of the most widely studied thermochemical cycles is the Sulfur-Iodine cycle, the development of which has recently slowed due to the difficulty in the separation of hydrogen iodine from a hydrogen iodide-iodine-water azeotrope, material compatibility issues, and the perceived need use large amounts of iodine in the process. A modification of the Sulfur-Iodine thermochemical cycle that attempts to avoid those issues along with mitigating the need to process large amounts of water in the cycle was developed, in a cycle we describe as the Sulfur-Sulfur cycle. This new thermochemical cycle can be summarized by the reaction sequence shown below. [see abstract for chemical reactions] Previous work in our group demonstrated the viability of implementing the cycle's low temperature reactions (the first reaction pair, which we call the Bunsen reaction and the Hydrogen Sulfide Production (HSP) reactions) in ionic liquids, which removes the need to process large amounts of water and iodine in the reaction sequence, and minimizes the material compatibility issues, and also demonstrated the feasibility of stream reforming hydrogen sulfide. The present work focuses on an exergetic analysis of the Sulfur-Sulfur cycle, the careful determination of reaction kinetics for the HSP reaction, and developing a model of the kinetics of the low temperature reactions. The exergetic analysis was carried out based on the published thermochemical parameters for the species involved. The analysis showed that the maximum theoretical exergetic efficiency of the Sulfur-Sulfur cycle is nearly 70% with a strong dependence on the reaction temperature of the low temperature reactions. The kinetics of the Bunsen and HSP were investigated through iodine colorimetery and the effect of water was determined. This kinetic data was used for the development of a predictive kinetic model that could accurately monitor the progression of iodine through the reaction system. The work showed that the Bunsen reaction is very fast with an activation energy (E[subscript aB]) of 92.83 kJ/mol and a pre-exponential factor (k0) of 7.65E+14 min−1, while for the HSP reaction, they were determined to be 117.09 kJ/mole and 7.73E+16 min−1. Integration of these two reactions into a single differential model based on iodine concentration fit the experimental profile extremely well The effect of including a Lewis base other than water in the reaction mixture yielded promising results that warrant future development. Specifically, the rates of both the Bunsen and HSP reactions increased with an increase in the pK[subscript b] of the added Lewis base. A local protocol to recycle the ionic liquid, enabling it to be reused in new experiments, was successfully developed. When the recycled ionic liquid is employed, effects similar to those found through the inclusion of the Lewis base were observed, suggesting that a decomposition product remains in the recycled ionic liquid. This effect could be minimized by acid washing the recycled ionic liquid prior to use.

Download or read book Hydrogen and Sulfur from Hydrogen Sulfide II Ambient Temperature Electrolysis Using Oxidation of Hydrogen Sulfide by Air as the Prime Energy Source written by Edward A. Fletcher and published by . This book was released on 1983 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogen sulfide recovered from the sweetening of fossil fuels or sought as a mineral for its intrinsic value might be converted, in an electrolytic process which uses atmospheric oxygen, into pipeline pressure hydrogen and sulfur. Such a process may be an alternative to the Claus Process, which recovers only sulfur and uses the hydrogen wastefully. It is also suggested that electrolysis provides a mechanism by which other gaseous products, as well as hydrogen, may be brought to pipeline pressures easily. (Author).

Download or read book The Decomposition of Hydrogen Sulfide with Tungsten Catalyst written by Toby Robert Graves and published by . This book was released on 1970 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hydrogen and Sulfur Recovery from Hydrogen Sulfide Wastes written by and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A process for generating hydrogen and elemental sulfur from hydrogen sulfide waste in which the hydrogen sulfide is associated under plasma conditions and a portion of the hydrogen output is used in a catalytic reduction unit to convert sulfur-containing impurities to hydrogen sulfide for recycle, the process also including the addition of an ionizing gas such as argon to initiate the plasma reaction at lower energy, a preheater for the input to the reactor and an internal adjustable choke in the reactor for enhanced coupling with the microwave energy input.

Download or read book Development of a Continuous Catalytic Process for Recovery of Sulfur from Gas Containing Low Concentrations of Hydrogen Sulfide microform written by Tushar Kanti Ghosh and published by National Library of Canada. This book was released on 1985 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Decomposition of Hydrogen Sulphide written by Charles Francis Pickett and published by . This book was released on 1927 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: