Grantee Research Project Results
Final Report: Photocatalytic Recovery of Sulfur and Hydrogen From Hydrogen Sulfide
EPA Grant Number: R828598C786Subproject: this is subproject number 786 , established and managed by the Center Director under grant R828598
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Center for Science and Policy Applications for Coastal Environments (CSPACE)
Center Director: D'Elia, Christopher F
Title: Photocatalytic Recovery of Sulfur and Hydrogen From Hydrogen Sulfide
Investigators: Linkous, Clovis , T-Rassi, Ali , Murdov, Nazim
Institution: University of Central Florida
EPA Project Officer: Aja, Hayley
Project Period: September 1, 2000 through August 31, 2004
RFA: Gulf Coast Hazardous Substance Research Center (Lamar University) (1996) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , Targeted Research
Objective:
The sulfur content of petroleum can vary from less then 0.05 to more than 14% by weight, but generally falls in the range of 1 to 4% by weight. Most of the sulfur present in petroleum is organically bound in compounds such as thiols, thioethers, disulfides, thiophenes, benzothiophenes, and dibenzothiophenes. Petroleum refiners are under immense pressure to find an economical way to remove more sulfur from gasoline and diesel fuel, as governments worldwide mandate tough new air-quality standards requiring cleaner commercial fuels. To further exacerbate the problem, clean crude oil reserves are becoming less available, so that the sulfur content in the crude coming into the refinery continues to increase, thereby increasing the job of desulfurization.
The conventional approach to desulfurization is to treat the crude feedstock with H2 in the presence of a catalyst at elevated temperature and pressure. The result is purified hydrocarbon with the sulfur content held in the form of hydrogen sulfide, H2S. As a noxious, poisonous gas, the H2S must also be dealt with at the refinery in a subsequent decomposition process.
Various approaches to H2S decomposition that include H2 recovery have been studied. They include thermal decomposition, electrolysis, photocatalysis, and photoelectrolysis. In recent years, a photolytic method for H2S decomposition has been reported, where sodium sulfide was photochemically oxidized and water was reduced to make hydrogen using a high-pressure mercury lamp. This direct photolytic method was advantageous because it was an ambient temperature process, and there were no catalyst or electrode deactivation problems to deal with.
We have continued to develop the UV photolytic process. We have found that when bisulfide ion, HS-, was the predominate sulfur species present, sulfur was produced in equimolar amounts to the evolved H2. In the presence of excess bisulfide, the sulfur would be complexed to form principally disulfide ion, S22-, the simplest of the various polysulfide species. The disulfide species could be broken down by lowering the pH of the solution to recover the sulfur. At pH 9 and below, disulfide solutions become turbid as it frees sulfur to form a yellowish white precipitate. We eventually realized that this function could be performed by a scrubbing action on the H2S itself, leading to the possibility of a closed cycle operation. In addition, study of the absorption characteristics of the various sulfide species suggested that a low pressure mercury lamp, whose spectral distribution favors shorter wavelengths, principally 254 nm, was more effectively absorbed, and thus would provide better illumination of the sulfide solution.
A design of how an industrial plant for UV photolytic H2S decomposition would be configured is shown in Figure 1. The system consists of three major units: A - the scrubber and filtration apparatus; B - an H2S stripper or other outgassing unit; and C - the photoreactor. Hydrogen sulfide, H2S, coming from a hydrodesulfurization plant, a sour natural gas well, or other source, is bubbled into a scrubber where it encounters disulfide solution (10) coming from the photoreactor. An outlet (20) with a control valve (25) is in place to maintain an overpressure of H2S in the headspace and to function as a pressure relief valve. The H2S lowers the pH of the scrubber vessel solution (30), to about 7.0-7.5, whereupon the disulfide anion decomposes, freeing elemental sulfur, S°. The sulfur is collected by filtration (40) of the suspension through a ceramic frit or other fine, porous media.
Figure 1. Schematic of closed cycle UV photolytic H2S decomposition.
The filtrate continues onto the stripper unit (B), where the excess H2S is removed from the sulfide solution. The H2S is returned (50) to the foreline of the scrubber unit, while the sulfide solution (60) is fed to the photoreactor (C). The sulfide solution inside the photoreactor (70), consisting mainly of bisulfide ion, HS-, is oxidatively converted to elemental sulfur and then complexed with excess sulfide ion to make disulfide ion, while water is reduced to make H2, under the action of light source (80). The H2 gas percolates out the top of the photoreactor, while the disulfide solution is returned to the scrubber.
Summary/Accomplishments (Outputs/Outcomes):
1 patent approved: “Closed Cycle Photocatalytic Process for Decomposition of Hydrogen Sulfide to its Constituent Elements,” Clovis A. Linkous and Nazim Z. Muradov, US 6,572,829 B2, June 3, 2003.
2nd patent applied for: “UV Photochemical Option for Closed Cycle Decomposition of Hydrogen Sulfide to its Constituent Elements,” Cunping Huang and Clovis A. Linkous, application number 10/165,843, June 7, 2002.
Potential follow-on funding agencies/collaborators identified:
- FIPR (Florida Institute of Phosphate Research) -- treating H2S off-gassing from phosphate-fertilized landfills.
- Yildiz Technical and Golden Horn Universities, Istanbul, Turkey -- exploiting H2S reservoir in the Black Sea.
- Premcor, Inc., Port Arthur, TX -- potential alternative to Claus process treatment of H2S.
This project served the public interest by developing technologies whereby the emission of air pollutants from oil refineries, sewage treatment plants, and municipal landfills can be reduced. It also expanded our supply of natural gas by enabling the exploitation of gas wells that were formerly considered to be too sour to be of economic value. It also helped lower the cost of making clean diesel and gasoline by recycling process hydrogen within the petroleum refinery.
The system the tested at two different concentrations (0.05 M and 0.1 M) and four different pH values. Even though some colloidal sulfur could be seen as high as pH 9, to achieve a reasonable yield via filtration, the pH of the reactor was typically set in the pH 7-8 range. Even then, a marked dependence of sulfur yield and H2S consumption and coevolution with H2 was observed.
For each trial, a sample of the effluent gas from the photoreactor was analyzed via gas chromatography. Retention times for the various gases of interest had been determined by injections of the respective pure substances. The H2 peak occurred between 2 to 3 min, the N2 peak (residual from initial purge gas) occurred between 4 to 5 min, and H2S occurred between 18 to 20 min.
The chromatogram for pH 7.2 and [HS-] = 0.1 M showed a prominent peak for H2S in addition to the former two gases. For the larger H2S peaks, a small satellite peak between N2 and H2S was observed that seemed to be correlated to the amount of H2S. Its origin and identity at this point has not yet been determined.
A compilation of the trial data is shown in Table 1. The general trends were as expected: lowering pH resulted in increased sulfur and H2 yield, and also increased H2S consumption, but at the price of increasing H2S content in the effluent H2. In order to keep H2S at negligible levels, it was necessary to operate at initial [HS-] = 0.05 M, and at a pH of 7.3 or higher.
On the other hand, small amounts of H2S in the H2 feed to a hydrodesulfurization unit can be tolerated. Hydrogen recycle at a refinery can typically contain 5-15 % impurity species, much of which is H2S. Either way, an industrial unit may well be able to avoid installing an H2S stripping unit between scrubber and photoreactor, making the process more attractive. Continued efforts at developing this UV photolytic approach to making H2 are underway.
[HS-] (M) | pH | H2S scrubbed (ml) | Sulfur collected (g) | H2 collected (ml) | H2S observed in effluent |
---|---|---|---|---|---|
0.05 | 7.5 | 955 | 1.1 | 830 | no |
0.05 | 7.4 | 1400 | 1.21 | 835 | no |
0.05 | 7.3 | 1900 | 1.23 | 840 | no |
0.05 | 7.2 | 2400 | 1.32 | 870 | yes |
0.1 | 7.5 | 2600 | 1.2 | 1060 | yes |
0.1 | 7.4 | 3600 | 1.40 | 1090 | yes |
0.1 | 7.3 | 6100 | 1.64 | 1200 | yes |
0.1 | 7.2 | 7400 | 1.7 | 1180 | yes |
Conclusions:
Offer patented technology to the oil patch or other industry where treatment of hydrogen sulfide is an issue.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other subproject views: | All 5 publications | 1 publications in selected types | All 1 journal articles |
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Other center views: | All 359 publications | 104 publications in selected types | All 90 journal articles |
Type | Citation | ||
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Linkous CA, Huang CP, Fowler JR. UV photochemical oxidation of aqueous sodium sulfide to produce hydrogen and sulfur. Journal of Photochemistry and Photobiology A: Chemistry 2004;168(3):153-160. |
R828598 (Final) R828598C786 (Final) |
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Supplemental Keywords:
Supplemental Keywords: hydrodesulfurization, hydrogen sulfide, hydrogen energy, sulfur recovery, photochemistry,, RFA, Scientific Discipline, Air, Toxics, TREATMENT/CONTROL, POLLUTANTS/TOXICS, Air Quality, Air Pollution, particulate matter, air toxics, Environmental Chemistry, Pollution Control, Chemicals, VOCs, Chemistry, Atmospheric Sciences, Engineering, Engineering, Chemistry, & Physics, Environmental Engineering, emission control strategies, stationary sources, air pollutants, emission control technologies, photocatalytic recovery, industrial emissions, pollution control technologies, emissions, ambient emissions, industrial air pollution, Hydrogen sulfide, PM, sulfur recovery, economic analysis, toxic contaminants, air pollution control technology, Volatile Organic Compounds (VOCs), emissions contol engineeringProgress and Final Reports:
Original AbstractMain Center Abstract and Reports:
R828598 Center for Science and Policy Applications for Coastal Environments (CSPACE) Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
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R822721C627 The Interaction of Microbial Activity and Zero Valent Iron Permeable Barrier Technology
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R822721C633 Catalyst Lifetime Studies for Chlorocarbon Steam Reforming
R822721C635 Electrokinetic/Surfactant-Enhanced Remediation of Hydrophobic Pollutants in Low Permeability Subsurface Environments
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R822721C651 Adjustable Biopolymer Chelators for Cadmium, Lead and Mercury
R822721C653 New Electrochemically Smart Catalysts for Hazardous Waste Management and Development of Capillary Electrophoresis for Analysis of their Products
R822721C655 Soil Sampling in South Alabama Oil Fields
R822721C659 Subsurface Contamination Site Characterization via a Computer-Aided Visual Tool
R822721C661 New Insoluble supports for Protein Immobilization for Use in Metalloprotein Affinity Metal Chromatography
R822721C663 Soil Remediation with Ultra-High-Efficiency Hydrocyclones
R822721C669 Solid Acid Catalyzed Alkylation in Supercritical Fluids
R822721C679 Regeneration/Reactivation of Carbon Adsorbents by Radio Frequency (RF) Induction Heating
R822721C687 Improved Halogen Resistance of Catalytic Oxidation
R822721C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R822721C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R822721C700 Effects of Natural and Cyclic Variations on Contaminant Fate and Transport
R822721C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R826694C620 Colloidal Fouling of Membranes: Implications in the Treatment of Textile Dye Wastes and Water Reuse
R826694C625 Enhanced Treatment of DNAPLs Contaminated Soils and Groundwater Using Biosurfactants: In-Situ Bioremediation
R826694C626 Catalytic Hydroprocessing of Chlorinated Wastes
R826694C627 The Interaction of Microbial Activity and Zero Valent Iron Permeable Barrier Technology
R826694C629 Biofiltration of BTEX in Petroleum-Contaminated Soil Remediation Off-Gas
R826694C630 Microbial Cometabolism of Recalcitrant Chemicals in Contaminated Air Streams
R826694C633 Catalyst Lifetime Studies for Chlorocarbon Steam Reforming
R826694C635 Electrokinetic/Surfactant-Enhanced Remediation of Hydrophobic Pollutants in Low Permeability Subsurface Environments
R826694C636 Transformation Reactions of Nitroaromatic and Nitrogen Heterocyclic Compounds on Granular Activated Carbon (GAC) Surfaces: Enhancement of GAC Adsorption in Natural and Engineered Environmental Systems
R826694C640 Environmentally Friendly Organic Synthesis in Supercritical Fluids
R826694C645 Development and Evaluation of an Integrated Model to Facilitate Risk-Based Corrective Action at Superfund Sites
R826694C651 Adjustable Biopolymer Chelators for Cadmium, Lead, and Mercury Remeidation
R826694C659 Subsurface Contamination Site characterization Via a Computer-Aided Visual Tool
R826694C661 New Insoluble supports for Protein Immobilization for Use in Metalloprotein Affinity Metal Chromatography
R826694C669 Solid Acid Catalyzed Alkylation in Supercritical Reaction Media
R826694C679 Regeneration and Reactivation of Carbon Adsorbents by Radio Frequency Induction Heating
R826694C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R826694C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R826694C700 Effects of Natural Cyclic Variations on Contaminated Fate and Transport
R826694C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R826694C705 A Pilot Plant for Producing Mixed Ketones from Waste Biomass
R826694C722 The Effects of an Oily-Phase on VOC Emissions from Industrial Wastewater
R826694C724 Mercury Removal from Stack Gas by Aqueous Scrubbing
R826694C725 Transport, Fate and Risk Implications of Environmentally Acceptable Endpoint Decisions
R826694C731 Development and Application of a Real-Time Optical Sensor for Atmospheric Formaldehyde
R826694C734 An Advanced System for Pollution Prevention in Chemical Complexes
R828598C001 Field Study Abstract: A Model of Ambient Air Pollution in Southeast Texas Using Artificial Neural Network Technology
R828598C002 Hollow Fiber Membrane Bioreactors for Treating Water and Air Streams Contaminated with Chlorinated Solvents
R828598C003 Fugitive Emissions of Hazardous Air Pollutants from On-Site Industrial Sewers
R828598C004 Biofiltration Technology Development
R828598C005 A Risk-Based Decision Analysis Approach for Aquifers Contaminated with DNAPLs
R828598C006 In-Situ Remediation for Contaminated Soils Using Prefabricated Vertical Drains
R828598C007 Membrane Technology Selection System for the Metal Finishing Industry
R828598C008 Sequential Environments for Enhanced Bioremediation of Chlorinated Aliphatic Hydrocarbons
R828598C009 Waste Minimization in the Magnetic Tape Industry: Waterborne Coating Formulations for Magnetic Tape Manufacture
R828598C010 Soil Remediation by Agglomeration with Petroleum Coke
R828598C011 Recovery of Dilute Phosphoric Acid in Waste Streams Using Waste Gas Ammonia: The Regenerative MAP/DAP Process
R828598C012 Stochastic Risk Assessment for Bioremediation
R828598C013 Selective Removal of Heavy Metals from Wastewater by Chelation in Supercritical Fluids
R828598C014 Optimization of Treatment Technologies for Detoxification of PCB Contaminated Soils
R828598C015 Wastewater Remediation by Catalytic Wet Oxidation
R828598C016 Permanence of Metals Containment in Solidified and Stabilized Wastes
R828598C017 Combustion Enhancement by Radial Jet Reattachment - Low Generation of Hazardous Gases and High Thermal Efficiency
R828598C018 A Process To Convert Industrial Biosludge and Paper Fines to Mixed Alcohol Fuels
R828598C019 Homogeneous Catalysis in Supercritical Carbon Dioxide
R828598C020 Ultrasonic Enhancement of the Removal of Heavy Metals
R828598C021 The Binding Chemistry and Leaching Mechanisms of Advanced Solidification/Stabilization Systems for Hazardous Waste Management
R828598C022 Development of an Air-Stripping and UV/H2O2 Oxidation Integrated Process To Treat a Chloro-Hydrocarbon-Contaminated Ground Water
R828598C023 A Comparative Study of Siting Opposition in Two Counties
R828598C024 Sonochemical Treatment of Hazardous Organic Compounds II: Process Optimization and Pathway Studies
R828598C025 Laser Diagnostics of the Combustion Process within a Rotary Kiln Incinerator
R828598C026 Use of Inorganic Ion Exchangers for Hazardous Waste Remediation
R828598C027 Kaolinite Sorbent for the Removal of Heavy Metals from Incinerated Lubricating Oils
R828598C028 Destruction of Chlorinated Hydrocarbons in Process Streams Using Catalytic Steam Reforming
R828598C029 Integrated Process Treatment Train (Bioremediation {Aerobic/Anaerobic} and Immobilization) for Texas Soils Contaminated with Combined Hazardous Wastes
R828598C030 Photo-Oxidation by H2O2/VisUV of Off-Gas Atmospheric Emissions from Industrial and Environmental Remediation Sources
R828598C031 Concentrated Halide Extraction and Recovery of Lead from Soil
R828598C032 Biodegradable Surfactant for Underground Chlorinated Solvent Remediation
R828598C033 A Software Guidance System for Choosing Analytical Subsurface Fate and Transport Models Including a Library of Computer Solutions for the Analytical Models
R828598C034 Hydrodynamic Modeling of Leachate Recirculating Landfill
R828598C035 Measurement of Oxygen Transfer Rate in Soil Matrices
R828598C036 Sorbent Technology for Multipollutant Control During Fluidized Bed Incineration
R828598C037 Pollution Prevention by Process Modification Using On-Line Optimization
R828598C038 Pollution Prevention by Process Modification
R828598C039 Water Solubility and Henry's Law Constant
R828598C040 Transferring Technical Information on Hazardous Substance Research by Publishing on the World Wide Web
R828598C041 Stress Protein Responses to Multiple Metal Exposure in Grass Shrimp
R828598C042 Life-Cycle Environmental Costing for Managing Pollution Prevention in the Chemical and Petroleum Refining Industries: A Cross-Border Approach
R828598C687 Improved Halogen Resistance of Catalytic Oxidation Through Efficient Catalyst Testing
R828598C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R828598C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R828598C700 Effects of Natural Cyclic Variations on Contaminated Fate and Transport
R828598C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R828598C705 A Pilot Plant for Producing Mixed Ketones from Waste Biomass
R828598C722 The Effects of an Oily-Phase on VOC Emissions from Industrial Wastewater
R828598C724 Mercury Removal from Stack Gas by Aqueous Scrubbing
R828598C725 Transport, Fate and Risk Implications of Environmentally Acceptable Endpoint Decisions
R828598C731 Development and Application of a Real Time Optical Sensor for Atmospheric Formaldehyde
R828598C734 An Advanced System for Pollution Prevention in Chemical Complexes
R828598C743 Field Demonstration of Ultrasound Enhancement of Permeable Treatment Walls
R828598C744 Optical Fibers Coated With Titania Membrane/UV-Generating Crystal in a Distributed-Light Photoreactor for VOC Oxidation
R828598C749 Characterization and Modeling of Indoor Particulate Contaminants In a Heavily Industrialized Community
R828598C753 Adsolubilization and Photocatalysis in a Semiconducting Monolithic Reactor for Wastewater Treatment
R828598C754 Remote Detection of Gas Emissions in Industrial Processes
R828598C759 Searching for Optimum Composition of Phosphogypsum: Fly ash: Cement Composites for Oyster Culch Materials
R828598C761 Development of a Phytologically-Based Biosorptive Water Treatment Process
R828598C766 Chlorinated Solvent Impact and Remediation Strategies for the Dry Cleaning Industry
R828598C769 Soil/Sediment Remediation by Hot Water Extraction Combined with In-Situ Wet Oxidation
R828598C771 Fluoracrylate Polymer Supported Ligands as Catalysts for Environmentally Benign Synthesis in Supercritical Fluids
R828598C774 The Feasibility of Electrophoretic Repair of Impoundment Leaks
R828598C777 Surfactant Enhanced Photo-oxidation of Wastewaters
R828598C778 Stationary Power Generation Via Solid Oxide Fuel Cells: A Response to Pollution and Global Warming
R828598C786 Photocatalytic Recovery of Sulfur and Hydrogen From Hydrogen Sulfide
R828598C787 Biosurfactant Produced from Used Vegetable Oil for removal of Metals From Wastewaters and Soils
R828598C789 Genetic Engineering of Enzymatic Cyanide Clearance
R828598C791 Characterizing the Intrinsic Remediation of MTBE at Field Sites
R828598C799 Simultaneous Water Conservation/Recycling/Reuse and Waste Reduction in Semiconductor Manufacturing
R828598C801 Building Defined Mixed Cultures To Biodegrade Diverse Mixtures Of Chlorinated Solvents
R828598C802 Engineering of Nanocrystal Based Catalytic Materials for Hydroprocessing of Halogenated Organics
R828598C807 Commercial Demonstration of Hydrogen Peroxide Injection to Control NOx Emissions from Combustion Sources
R828598C809 Evaluating Source Grouting and ORC for Remediating MTBE Sites
R828598C810 Application of Total Cost Assessment To Process Design In the Chemical Industry
R828598C846 Quantitative Demonstration of Source-Zone Bioremediation in A Field-Scale Experimental Controlled Release System
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
1 journal articles for this subproject
Main Center: R828598
359 publications for this center
90 journal articles for this center