Liquid redox sulfur recovery processes remove H2S from sour gas streams and produce elemental sulfur for sale or disposal. The Stretford Process is one of the oldest commercial liquid redox processes and it is based on a vanadium and anthraquinone redox system. Improvements in the operability and reliability of the Stretford process would be beneficial to the process user. The report presents results of research focused on developing an understanding of the process parameters and factors that impact sulfur by-product formation (e.g., sodium thiosulfate and sodium sulfate) in the Stretford process. The information in the report can help current Stretford plant process users better understand the operations of their plants, especially with regards to sulfur by-product formation and control strategies.
This project was funded by the U.S. Department of Energy (DOE) to test a hybrid sulfur recovery process for natural gas upgrading. The process concept represents a low cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day. This process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both on-shore and offshore applications. CrystaSulf (service mark of Gas Research Institute) is a new nonaqueous sulfur recovery process that removes hydrogen sulfide (H{sub 2}S) from gas streams and converts it into elemental sulfur. CrystaSulf features high sulfur recovery similar to aqueous-iron liquid redox sulfur recovery processes, but differs from the aqueous processes in that CrystaSulf controls the location where elemental sulfur particles are formed. In the hybrid process, approximately 1/3 of the total H{sub 2}S in the natural gas is first oxidized to SO{sub 2} at low temperatures over a heterogeneous catalyst. Low temperature oxidation is done so that the H{sub 2}S can be oxidized in the presence of methane while avoiding methane oxidation. The project involved the development of a detailed plan for laboratory and bench scale-up application, laboratory/bench-scale catalyst testing, and demonstration of scale-up economic advantages. The bench-scale tests examined two different catalysts that are promoted modifications of TDA's patented partial oxidation catalyst used to make elemental sulfur. The experiments showed that catalyst TDA No.2 is superior for use with the hybrid CrystaSulf process in that much higher yields of SO{sub 2} can be obtained. Continued testing is planned.
This first quarter report of 2001 describes progress on a project funded by the U.S. Department of Energy (DOE) to test a hybrid sulfur recovery process for natural gas upgrading. The process concept represents a low cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day. This process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both on-shore and offshore applications. CrystaSulf (service mark of Gas Research Institute) is a new nonaqueous sulfur recovery process that removes hydrogen sulfide (H{sub 2}S) from gas streams and converts it into elemental sulfur. CrystaSulf features high sulfur recovery similar to aqueous-iron liquid redox sulfur recovery processes, but differs from the aqueous processes in that CrystaSulf controls the location where elemental sulfur particles are formed. In the hybrid process, approximately 1/3 of the total H{sub 2}S in the natural gas is first oxidized to SO{sub 2} at low temperatures over a heterogeneous catalyst. Low temperature oxidation is done so that the H{sub 2}S can be oxidized in the presence of methane and other hydrocarbons without oxidation of the hydrocarbons. The project involves the development of a catalyst using laboratory/bench-scale catalyst testing, and then demonstration of the catalyst at CrystaTech's pilot plant in west Texas. During this reporting period tests were done to determine the effect of hydrocarbons such as n-hexane on catalyst performance with and without H{sub 2}S present. The experiments showed that hexane oxidation is suppressed when H{sub 2}S is present. Hexane represents the most reactive of the C1 to C6 series of alkanes. Since hexane exhibits low reactivity under H{sub 2}S oxidation conditions, and more importantly, does not change the SO{sub 2} selectivity, we can conclude that the C1-C6 hydrocarbons should not significantly interfere with the oxidation of H{sub 2}S into SO{sub 2}. Plans to determine the effect of aromatic compounds on catalyst performance for extended periods, and for catalyst pelletization and continued testing are described.
This second quarter report of 2002 describes progress on a project funded by the U.S. Department of Energy (DOE) to test a hybrid sulfur recovery process for natural gas upgrading. The process concept represents a low cost option for direct treatment of natural gas streams to remove H{sub 2}S in quantities equivalent to 0.2-25 metric tons (LT) of sulfur per day. This process is projected to have lower capital and operating costs than the competing technologies, amine/aqueous iron liquid redox and amine/Claus/tail gas treating, and have a smaller plant footprint, making it well suited to both on-shore and offshore applications. CrystaSulf (service mark of CrystaTech, Inc.) is a new nonaqueous sulfur recovery process that removes hydrogen sulfide (H{sub 2}S) from gas streams and converts it into elemental sulfur. CrystaSulf features high sulfur recovery similar to aqueous-iron liquid redox sulfur recovery processes, but differs from the aqueous processes in that CrystaSulf controls the location where elemental sulfur particles are formed. In the hybrid process, approximately 1/3 of the total H{sub 2}S in the natural gas is first oxidized to SO{sub 2} at low temperatures over a heterogeneous catalyst. Low temperature oxidation is done so that the H{sub 2}S can be oxidized in the presence of methane and other hydrocarbons without oxidation of the hydrocarbons. The project involves the development of a catalyst using laboratory/bench-scale catalyst testing, and then demonstration of the catalyst at CrystaTech's pilot plant in west Texas. Previous reports described development of a catalyst with the required selectivity and efficiency for producing sulfur dioxide from H{sub 2}S. In the laboratory, the catalyst was shown to be robust and stable in the presence of several intentionally added contaminants, including condensate from the pilot plant site. This report describes testing using the laboratory apparatus but operated at the pilot plant using the actual pilot plant gas, which contains far more contaminants than can be simulated in the laboratory. The results are very encouraging, with stable and efficient operation being obtained for a prolonged period of time.
Abstract : High current, short duration pulses were investigated as methods for determining the state-of-charge of nickel-cadmium and zinc-silver oxide batteries. An accurate indicator over the whole state-of-charge range for nickel-cadmium batteries was developed on the basis of a constant voltage discharge pulse and a preconditioning step. The effects of temperature, cycling, and cell variations on test results were determined. The procedure was shown to be able to test cells of unknown background and to detect the presence of weak or defective cells. A constant voltage discharge pulse test was developed to determine if a zinc-silver oxide battery was charged above 80-85% of full capacity.
High current, short duration pulses were investigated as methods for determining the state-of-charge of nickel--cadmium and zinc--silver oxide batteries. An accurate indicator over the whole state-of-charge range for nickel--cadmium batteries was developed on the basis of a constant voltage discharge pulse and a preconditioning step. The effects of temperature, cycling, and cell variations on test results were determined. The procedure was shown to be able to test cells of unknown background and to detect the presence of weak or defective cells. A constant voltage discharge pulse test was developed to determine if a zinc--silver oxide battery was charged above 80--85% of full capacity. (GRA)
This document is the final report for Cooperative Agreement DE-FC26-04NT42314, 'Kinetics Study of Mercury Reactions in FGD Liquors'. The project was co-funded by the U.S. DOE National Energy Technology Laboratory and EPRI. The objective of the project has been to determine the mechanisms and kinetics of the aqueous reactions of mercury absorbed by wet flue gas desulfurization (FGD) systems, and develop a kinetics model to predict mercury reactions in wet FGD systems. The model may be used to determine optimum wet FGD design and operating conditions to maximize mercury capture in wet FGD systems. Initially, a series of bench-top, liquid-phase reactor tests were conducted and mercury species concentrations were measured by UV/visible light spectroscopy to determine reactant and byproduct concentrations over time. Other measurement methods, such as atomic absorption, were used to measure concentrations of vapor-phase elemental mercury, that cannot be measured by UV/visible light spectroscopy. Next, a series of bench-scale wet FGD simulation tests were conducted. Because of the significant effects of sulfite concentration on mercury re-emission rates, new methods were developed for operating and controlling the bench-scale FGD experiments. Approximately 140 bench-scale wet FGD tests were conducted and several unusual and pertinent effects of process chemistry on mercury re-emissions were identified and characterized. These data have been used to develop an empirically adjusted, theoretically based kinetics model to predict mercury species reactions in wet FGD systems. The model has been verified in tests conducted with the bench-scale wet FGD system, where both gas-phase and liquid-phase mercury concentrations were measured to determine if the model accurately predicts the tendency for mercury re-emissions. This report presents and discusses results from the initial laboratory kinetics measurements, the bench-scale wet FGD tests, and the kinetics modeling efforts.
Injection of carbon dioxide (CO/sub 2/) is a promising method for recovering large amounts of oil that cannot be recovered by conventional (primary and secondary) technology. As with any relatively new technology, there are aspects of CO/sub 2/ injection that, without adequate assessment, could discourage its use. One of these aspects is the potential for increased corrosion of oil field equipment that could result from CO/sub 2/ injection. Purpose of this study is to document the specific effects of CO/sub 2/ on corrosion and to identify promising methods for controlling corrosion in fields using CO/sub 2/ injection.
Abstract Mit Hilfe eines neu entwickelten galvanodynamischen Verfahrens, das für die Untersuchung der Lochfraßkorrosion ganz allgemein von Bedeutung sein könnte, wird die Inhibierung des Lochfraßes an rostfreiem Stahl der Type 304L durch den oberflächenaktiven Chelatbildner N‐Laurylsarkosin in wäßrigen CF‐haltigen Lösungen untersucht.
Radian and Ultrasystems performed laboratory and bench-scale studies to obtain operational information on the Hiperion liquid redox sulfur recovery process. Specific activities included analytical methods development and verification, bench-scale testing, 1,4 naphthoquinone disulfonate stability testing, and reoxidation testing. A definite conclusion regarding the suitability of the Hiperion process for natural gas desulfurization could not be reached due to contractual difficulties which led to GRI's deferring the work.
