Abstract Booklet 2006 - Swanson School of Engineering - University ...

More documents

Recommendations

Info

solid sorbents; and separation by membranes. In one concept, a wet scrubbing technique is being investigated that uses a physical solvent process to remove CO 2 from fuel gas of an IGCC system at elevated temperature and pressure. The need to define an ideal solvent has led to the study of the solubility and mass transfer properties of various solvents. Fabrication techniques and mechanistic studies for hybrid membranes separating CO 2 from the fuel gas produced by coal gasification are also being performed. Membranes that consist of CO 2 -philic silanes incorporated into an alumina support or ionic liquids encapsulated into a polymeric substrate have been investigated for permeability and selectivity. An overview of two novel techniques is presented along with a research progress status of each technology. P2-2 Selective Catalytic Oxidation of Hydrogen Sulfide - Systems Analysis for IGCC Application Richard A. Newby, Dale L. Keairns, Science Applications International Corporation, USA Maryanne Alvin, DOE/NETL, USA Selective catalytic oxidation of hydrogen sulfide (SCOHS) has been evaluated conceptually for IGCC applications, and the theoretical limits of reaction performance, process performance, and economic potential in IGCC have been estimated. Syngas conditions that have high partial pressures of total sulfur result in substantial liquid sulfur retention within the catalyst bed, with relatively complex processing being required. Applications that have much lower total sulfur partial pressure in the process gas might permit SCOHS operation under conditions where little liquid sulfur is retained in the catalyst, reducing the processing complexity and possibly improving the desulfurization performance. The results from our recent IGCC process evaluations using the SCOHS technology and conventional syngas cleaning are presented, and alternative SCOHS process configurations and applications that provide greater performance and cost potential are identified. P2-3 Optimization of Heat Recovery Steam Generators for IGCC Power Plants D. N. Reddy, Osmania University, INDIA Basic human needs can be met only through industrial growth, which depends to a great extent on energy supply. The large increase in population during the last few decades and the spun in industrial growth have placed tremendous burden on the electrical utility industry and process plants producing chemicals, fertilizers, petrochemicals, and other essential commodities, resulting in the need for additional capacity in the areas of power and steam generation throughout the world. Steam is used in nearly every industry; and it is well known fact that steam generators and heat recovery boilers are vital to power and process plants. It is no wonder that with rising fuel and energy costs engineers in these, fields are working on innovative methods to generate electricity, improve energy utilization in these plants, recover energy efficiently, from various waste gas sources, and simultaneously minimize the impact these processes have on environmental pollution and the emission of harmful gases to the atmosphere. Heat recovery boilers, also known as waste heat recovery boilers or heat recovery steam generators (HRSGs), form an inevitable part of chemical plants, refineries, power plants, and process systems. They are classified in several ways, according to the application, the type of boiler used, whether the line gas is used for process or mainly for energy recovery, cleanliness of the gas, and boiler configuration, to mention a few. The main clarification is based on whether the boiler is used for process purposes or for energy recovery. Process waste heat boilers are used to cool waste gas streams from a given inlet temperature to a desired exit temperature for further processing purposes. An example can be found in the chemical industry in a sulfuric acid or hydrogen plant- where the gas steam is cooled to a particular gas temperature and then taken to a reactor for further processing. The exit gas temperature from the boiler is an important parameter affecting the downstream process reactions and hence is controlled by using a gas bypass system. Steam generation is of secondary importance in such plants. In energy recovery applications, on the other hand, the gas is cooled as much as possible while avoiding low temperature corrosion and steam generation throughout the world. Steam is used in nearly every industry; and it is well known that steam generators and heat recovery boilers are vital to power and process plants. It is no wonder that with rising fuel and energy cost engineers in these, fields are working on innovative methods to generate electricity, improve energy utilization in these plants, recover energy efficiently, from various waste gas sources, and simultaneously minimize the impact these processes have on environmental pollution and the emission of harmful gases to the atmosphere. P2-4 Thermogravimetric characteristics and kinetic of coal/plastic blends co-pyrolysis Limin Zhou, Yipin Wang, Qunwu Huang, Junqing Cai, Tianjin University, CHINA Co-pyrolytic behaviours of different plastics(high density polyethylene, low density polyethylene and polypropylene) and low volatile coal (LVC) were investigated using TGA. The results indicated that coal was decomposed at in the temperature range 174- 710°C, while the thermal degradation temperature of plastic is 438-521°C. Plastics showed similar pyrolysis behaviors due to similar chemical bonds in their molecular structures. The overlapping degradation temperature interval between coal and plastic is beneficial to hydrogen transfer from plastic to coal. The difference of weight loss (ΔW) between experimental and theoretical ones, calculated as a algebraic sums of those from each separated component, is about 5-6% at 550-650°C. These experimental results indicate on significant synergistic effect during plastic and biomass co-pyrolysis at the high temperature region. In addition, a kinetic analysis was performed to fit thermogavimetric data, the global processes being considered as one to three consecutive first order reactions. A reasonable fit to the experimental data was obtained for all materials and their blends. P2-5 Solvent Extraction of South African Coal-A Review Johan van Dyk, TJ van de Walt, Sasol Technology, SOUTH AFRICA Sasol’s Secunda plants in South Africa are very conveniently placed with respect to the vast coal reserves of the Mpumulanga region. Sasol converts these coal reserves, via its indirect liquefaction process, into liquid fuels and various chemicals. This process is operated under severe process conditions, and the concomitant release of big volumes of CO 2 presents environmental problems. In addition to this, these plants consume utilities other than coal (such as water) and need the support of a well developed infrastructure (like e.g. a good roads network). Other, more remote (with respect to the Secunda plants) coal reserves may be in need of a different kind of coal conversion technology before these can be monetised. Such is the case for the Waterberg coal reserves – coal that is high in vitrinite content and may be eminently suitable for conversion via coal solvent extraction. The coal solvent extraction process is mild (with respect to process conditions) and CO 2 release is low; coal is the major utility consumed in light of the process being self-sustainable in terms of the solvent that is required. The product from solvent extraction (mild coal dissolution) is a lowash and low-sulphur solid or pitch and is suitable for use as a fuel in new technology power generation plants, or as a reductant in the metallurgical industry, and even as a precursor for several carbon products. Coal solvent extraction is a well known technology and the majority of literature is based on vitrinite rich coal. Little work is reported on the mild solvent extraction of inertinite rich coals, or the role of other reactive macerals (besides vitrinite). Thus, work on South African coal, also rich in other reactive macerals, is reviewed. P2-6 Regenerable Sorbent Development for Sulfur and Chloride Removal From Coal-Derived Synthesis Gas Ranjani Siriwardane, DOE/NETL, USA Thomas Webster, Research Development Solutions, USA A large number of components in coal form corrosive and toxic compounds during gasification processes. According to the U.S. Department of Energy, National Energy Technology Laboratory (DOE NETL) goals, contaminants have to be reduced to parts per billion in order to utilize gasification gas streams in fuel cell applications. Even more stringent requirements are expected if the fuel is to be utilized in chemical production applications. Regenerable hydrogen sulfide removal sorbents have been developed at DOE NETL. These sorbents can remove the hydrogen sulfide to parts per billion range at 316°C and at 20 atmospheres. The sorbent can be regenerated with oxygen. Reactivity and physical durability of the sorbent did not change during the multi-cycle tests. Results of the multi-cycle, benchscale tests utilizing simulated coal gas and results of the tests with real coal gas will be discussed in the paper. Regenerable hydrogen chloride removal sorbents have also been developed at DOE NETL. These sorbents can remove HCl to parts per billion range at 300°C to 500°C. The sorbent can be regenerated with oxygen. Results of thermogravimetric analysis and bench-scale flow reactor tests with both regenerable and non-regenerable HCl removal sorbents will be discussed in the paper. P2-7 Assessment and Environmental Performance of Coal and Biomass Based Combined Heat and Power Plants (CHP) D.N. Reddy, K. Basu, Osmania University, INDIA Shortage and quality of grid power prompted Indian Industries to go for captive power plants. For process industries, uninterrupted steam supply becomes a necessity. Generally, coal based captive power plants are employed for these duties. These plants have efficiency range between 5% to 10%. Biomass based Combined Heat and Power plant (CHP) could improve both generation efficiency and environmental performance. Biomass based power generation using reciprocating engine is well established technology. However, low life expectancy and higher cost of generation slowed down the wider adaptation of this technology. Gas turbine manufacturers are pursuing development of burning Low Btu gas in combustor. Biomass gasifier integrated to gas turbine as topping cycle and steam Turbine as bottoming cycle could provide power cycle efficiency of 2% to 4% higher than that of conventional power plant. Centre for Energy Technology carried out designs of a CHP plant utilizing the existing equipment. In spite of limitation on component efficiency, power block can attain a net thermal efficiency of 9.9 and CHP efficiency of 49.79 for a plant capacity of 51.72 kWe. The validation of the mathematical models was carried out by using 50
experimental data available in literature and data from the equipment available at CET. The report presents the considerations for equipment selection and sensivity analysis of down-draft Gasifier and design of HRB. P2-8 Removal of H 2 S in Gas from Coal Gasification Using a Polymer Sorbent Supported on Mesoporous Molecular Sieves Xiaoxing Wang, Xiaoliang Ma, Chunshan Song, The Pennslyvania State University, USA The deep removal of H 2 S from natural gas, coal/biomass gasification gas and the reformate is one of the major challenges in the hydrogen production process and utilization of these fuel gases. In order to develop a more efficient sorbent with high capacity, selectivity and regenerability, a series of polyethylenimine (PEI) sorbents supported on mesoporous molecular sieves, including SBA-15, MCM-41 and MCM- 48, have been prepared and characterized by XRD and N 2 physisorption. The sorption performance of the prepared sorbents for removing H 2 S from a simulated coal gasification gas, which contains 4000 ppmv H 2 S and 20 vol% H 2 in nitrogen, has been tested in a fix-bed system at a temperature range from 22 to 75°C. The effects of operating conditions, including temperature, gas hourly space velocity (GHSV), on the sorption performance have been examined in detail. It is found that the increase in temperature and GHSV resulted in the decrease of the breakthrough capacity. The breakthrough capacity and the saturation capacity of the supported PEI sorbents change with the PEI loading. A positive synergetic effect between SBA-15 support and loading PEI on H 2 S sorption was observed. The maximum breakthrough capacity of 1.97 mmol/g-PEI was obtained at a PEI loading of 50 wt %, while the maximum saturation capacity of 4.65 mmol/g-PEI was obtained at a PEI loading of 65 wt %. The comparison of the supports indicates that the higher porous volume and the threedimension channel structure favor improving the sorption performance. The desorption and regeneration of the spent sorbents have also been conduced in the fix-bed system at 22 and 75°C, respectively. It indicates that desorption of the saturated sorbents can be conducted easily at 75°C and the sorbent is stable during the adsorption-desorption cycles. The results imply that the developed sorbent is a promising sorbent for removing H 2 S from gas streams at more environmentally friendly and energetically efficient conditions. In addition, the mechanism for the sorption of H 2 S on the supported PEI is also discussed on the basis of the experimental and computational results. P2-9 Investigating Reactive Ball Milling of Anthracite Coal Apurba Sakti, Caroline E. Burgess Clifford, Angela D. Lueking, The Pennsylvania State University, USA Development of alternative energy technologies is the key to address future energy concerns of depleting fossil fuel reserves and the hydrogen economy is one of the forerunners amongst the various options being considered. A combined hydrogen production and storage process using coal as a precursor and ball milling it in the presence of a hydrogen donating solvent is investigated here. Tests of our current hypotheses that ball milling induces cross links in the coal structure facilitated by the evolution of hydrogen will be presented. The effect of mineral matter present in the coals has been investigated as well and will be presented along with the possible commercial applications. P2-10 The Impact of Trace Impurities in Coal Gasification Products on the Performance of Solid Acid Catalysts for Phenolics Transformations Jack C. Q. Fletcher, Walter Bohringer, University of Cape Town, SOUTH AFRICA Cathy L. Dwyer, Sasol Technology Research and Development, SOUTH AFRICA The effect of impurities as potential catalyst poisons in the raw phenolics stream from a Lurgi coal gasifier was investigated for the transformation of phenolic compounds over zeolite H-MFI as a solid Brønsted acid catalyst. A model mixture of light phenolics, representing the major constituents of such a stream, was converted at 350ºC and 60 bar in the liquid phase. A series of potential catalyst poisons were added, individually, each representing the ‘parent compound’ of one of the families of typical impurities in such a stream. Conversion of p-cresol was monitored vs. time-on-stream as a catalyst activity indicator. After the introduction of poison, the response in catalyst activity, i.e. the conversion of p-cresol, ranged from a steeply declining behaviour to showing no effect at all. Upon re-introduction of poison-free feed, catalyst activity recovered, completely or in part, and was more or less rapid. Potential poisons that were evaluated, their applied concentrations (in wt -ppm) and the results obtained are as follows: - Pyridine (200), strong poisoning effect, partially reversible - Benzonitrile (3700), strong poisoning effect, presumably by the decomposition co-product NH 3 from hydrolysis with moisture, reversible - Aniline (200), weak poisoning effect, improved activity after removal - Indole (200), very weak poisoning effect, improved activity after removal - Thiophenol (850), no poisoning effect, no effect after removal 51 - Benzothiophene (850), very weak poisoning effect, slightly improved activity after removal. The strength of the poisoning effects reflects the basicity of the respective poison compounds and their adsorptive strength on the acid sites of the catalyst. From these findings it is apparent which gasifier impurities are problematic, and require removal, and which may be adequately managed during solid acid processing. POSTER SESSION 3 GAS TURBINES AND FUEL CELLS FOR SYNTHESIS GAS AND HYDROGEN APPLICATIONS P3-1 Syngas Fuel Composition Sensitivities of Combustor Flashback and Blowout David Noble, Quingguo Zhang, Tim Lieuwen, Georgia Institute of Technology, USA This paper reports experimental data detailing the fuel composition sensitivities of flashback and lean blowout limits of syngas (H 2 /CO/CH 4 mixtures). Data were obtained over a range of fuel compositions at fixed approach flow velocity, reactant temperature, and combustor pressure at several conditions up to 7.1 atm and 500 K inlet reactants temperature. Consistent with prior studies, these results indicate that the percentage of H 2 in the fuel dominates the mixture blowout characteristics. These blowout characteristics can be captured with classical Damköhler number scalings to predict blowoff equivalence ratios to within 10%. Counter-intuitively, the percentage of hydrogen had far less effect on flashback characteristics, at least for fuels with hydrogen mole fractions less than 60%. This is due to the fact that two mechanisms of “flashback” were noted: rapid flashback into the premixer, presumably through the boundary layer, and movement of the static flame position upstream along the centerbody. The former and latter mechanisms were observed at high and low hydrogen concentrations. In the latter mechanism, flame temperature, not flame speed, appears to be the key parameter describing flashback tendencies. P3-2 Effect of Syngas Composition on Emissions from an Idealized Gas Turbine Combustor Timothy C. Williams, Christopher R. Shaddix, Robert W. Schefer, Sandia National Laboratories, USA Future energy systems based on gasification of coal or biomass for co-production of electrical power and gaseous or liquid fuels may require gas turbine operation on unusual fuel mixtures. In addition, global climate change concerns may dictate the production of a CO 2 product stream for end-use or sequestration, with potential impacts on the oxidizer used in the gas turbine. In this study the operation at atmospheric pressure of a small, optically accessible swirl-stabilized premixed combustor, burning fuels ranging from pure methane to conventional and H 2 -rich and H 2 -lean syngas mixtures is investigated. Both air and CO 2 -diluted oxygen are used as the oxidizers. CO and NO x emissions for these flames have been determined over the full range of stoichiometries from the lean blow-off limit to slightly rich conditions (φ ~ 1.03). The presence of hydrogen in the syngas fuel mixtures results in more compact, higher temperature flames, resulting in increased flame stability and higher NO x emissions. The lean blowoff limit and the lean stoichiometry at which CO emissions become significant both decrease with increasing H 2 content in the syngas. For the investigated mixtures, CO emissions near the stoichiometric point do not become significant until φ > 0.95. At this stoichiometric limit, where dilute-oxygen power systems would preferably operate, CO emissions rise more rapidly for combustion in O 2 -CO 2 mixtures than for combustion in air. P3-3 Low Temperature Oxygen Activation and Transport over Doped Lanthanum Ferrites for Use as SOFC Cathodes John Kuhn, Umit Ozkan, The Ohio State University, USA Current Ni-based solid oxide fuel cells (SOFC) anodes deactivate in the presence of coal-derived gas because they are easily poisoned by low levels of sulfur and catalyze coke formation. Their use requires a large steam to carbon ratio to limit coking. In addition to these problems, the Ni-based anodes also lose activity through sintering. All of these processes deactivate the anodic reaction rates, cause low power densities, and increase operation costs due to large steam requirements. Thus, the development of highly active and carbon and sulfur tolerant materials suitable for use as anodes is necessary to bring coal-gas fed SOFC systems closer to commercialization. Ongoing SOFC cathode research shows iron-based perovskite materials are developed as promising materials for use as SOFC cathodes between 500°C and 700°C. The electrochemical activity and oxide ion mobility that make it such a great cathode material can also be harnessed for the oxidation reactions at the anode. The current research demonstrates the iron-based perovskite materials are stable in highly reducing conditions and possess catalytic activity for the direct oxidation of hydrogen and carbon monoxide in the desired temperature range. The effect of the increased lattice oxygen mobility on the water requirements and the influence of hydrogen sulfide
Page 1 and 2: TABLE OF CONTENTS Oral Sessions Pag
Page 3 and 4: 1-1 SESSION 1 GASIFICATION TECHNOLO
Page 5 and 6: The U.S. pioneered development of s
Page 7 and 8: 5-5 Enhanced Hydrogen Production wi
Page 9 and 10: derived synthesis gases employing i
Page 11 and 12: Several physical adsorbents, partic
Page 13 and 14: 13-1 SESSION 13 GASIFICATION TECHNO
Page 15 and 16: promising Clean Coal technologies u
Page 17 and 18: high selectivity (theoretically pro
Page 19 and 20: 19-3 Development of Highly Efficien
Page 21 and 22: The Aim of the project is the impro
Page 23 and 24: 24-3 Development of Fluidizable Lit
Page 25 and 26: the classical Lurgi-gasifcation pro
Page 27 and 28: 28-5 A Kinetic Approach to Catalyti
Page 29 and 30: turbine cycles. The models provide
Page 31 and 32: up to 290 psia and temperatures up
Page 33 and 34: 35-2 Development of Iron-Based Pero
Page 35 and 36: features of the BGL 1000 technology
Page 37 and 38: Heat-exchangers, particle filters,
Page 39 and 40: 41-4 Using Fly Ash-Based Foundry Co
Page 41 and 42: ocks using elemental ratios. Data f
Page 43 and 44: 600-900°C. Changes in the amount o
Page 45 and 46: ATL process has three stages, namel
Page 47 and 48: commercial-scale gasifier was shutd
Page 49 and 50: 52-5 Pilot-Scale Demonstration of U
Page 51: POSTER SESSION 1 COMBUSTION TECHNOL
Page 55 and 56: activation. It was concluded that C

Abstract Booklet 2006 - Swanson School of Engineering - University ...

Create successful ePaper yourself

Delete template?

Save as template?