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

More documents

Recommendations

Info

conditions of SR1=1.0 and SR1=1.2 is significantly larger than that at SR1=1.1 for high volatile coal at a fixed reburning fraction. 16-3 Low-Temperatures Reduction of NO Using V 2 O 5 /AC Catalyst from Flue Gas Zhanggen Huang, Zhenyu Liu, Pingguang Liu, Xianniu Hong, Zenghou Liu, Jue Ge, Chinese Academy of Sciences, CHINA V 2 O 5 /AC catalyst showed higher selective catalytic reduction (SCR) activity of NO in the presence of SO 2 at lower temperatures. Further study showed the V 2 O 5 /AC catalyst deactivated easily in the presence of H 2 O and SO 2 , which is due to the excess position of ammonium-sulfate salts on the catalyst surface. The position rate of ammoniumsulfate salts is governed by the rate difference between its formation and reaction with NO. Through decrease in the formation rate of ammonium-sulfate salts or increase in the reaction rate of ammonium-sulfate salts and NO, such as decrease in V 2 O 5 loading, mineral content of AC and space velocity, or increase in reaction temperature, the catalyst can be used stably at a space velocity of below 9000 h -1 and temperature of 250°C in the presence of SO 2 and H 2 O. In the real existing burner system, a fixed bed reactor, including reaction and regeneration system, is explored and the catalyst shows higher NO conversion at 150°C and 1000 h -1 for 30 day. Argonne National Laboratory (ANL) is developing dense cermet (i.e., ceramic-metal composite) membranes for separating hydrogen from mixed gases, particularly product streams generated during coal gasification and/or methane reforming. Hydrogen separation with these membranes does not require electrodes or an external power supply, and hydrogen separated from the mixed gas stream is of high purity, so post-separation purification steps are unnecessary. Cermet membranes were prepared by mixing ≈50 vol.% Pd with Y 2 O 3 -stabilized ZrO 2 . Using several feed gas mixtures, we measured the nongalvanic hydrogen permeation rate, or flux, for the cermet membranes in the temperature range of 500-900°C. This rate varied linearly with the inverse of membrane thickness and reached ≈33 cm 3 [STP]/min-cm 2 at 900°C for an ≈15-μm-thick membrane on a porous support structure when 100% H 2 at ambient pressure was used as the feed gas. Hydrogen flux measurements in H 2 S-containing atmospheres showed that the cermet membranes are stable for up to 1200 h at 900°C in gases that contain 400 ppm H 2 S. We have also measured the hydrogen flux through the cermet membrane at 500 and 600°C using a feed gas of 73% H 2 /400 ppm H 2 S/balance He. Because formation of palladium sulfide (Pd 4 S) can seriously degrade hydrogen permeation though Pd-containing membranes, we evaluated the chemical stability of the membranes by equilibrating samples in 73% H 2 /400 ppm H 2 S/balance He at temperatures in the range 400-900°C to determine the conditions under which palladium sulfide (Pd 4 S) forms. The present status of membrane development at Argonne will be presented in this paper. 16-4 SCR/SNCR Optimization with In-Situ Ammonium Bisulfate Fouling Measurement Charles Lockert, Breen Energy Solutions, USA 17-2 Single Membrane Reactor Configuration for Separation of Hydrogen, Carbon Dioxide and Hydrogen Sulfide Shain Doong, Raja Jadhav, Gas Technology Institute, USA Ammonia slip has long been considered one of the primary variables relating to overall performance of both SCR and SNCR NO x control processes. However, because ammonium bisulfate generation is related not only to ammonia slip, but the presence of SO 3 , moisture, and excess O 2 as well, its presence cannot be accurately predicted by an ammonia slip instrument alone. A novel technology has been introduced for the direct measurement of ammonium bisulfate related fouling tendencies. This instrument directly measures and reports both the formation temperature and the fouling potential of the ammonium bisulfate based fouling compounds. Data will be presented on the ammonium bisulfate instrument’s response, under full scale plant conditions, to varying levels of ammonia slip, its sensitivity to extremely low levels of ammonia, correlation between detected ammonium bisulfate activity and site specific air heater fouling as well as correlation between detected ammonium bisulfate activity and ammonia-on-ash concentrations. Further, this measurement feedback may be used to optimize the operation of SCR and SNCR systems. The measurement would be used to maximize NO x reduction while minimizing fouling across various loads and operating conditions. The specific control actions that can be taken include: • modifying urea/ammonia injection rates, • controlling air heater gas outlet temperature by controlling the amount of hot flue gas air heater bypass to maintain AH cold-end temperature above the AbS dew point, or • controlling air heater inlet air temperature with air preheating by steam coils to maintain AH cold-end temperature above the AbS dew point. A grid of AbS measurements may also be used to monitor SCR catalyst fouling as part of a catalyst management program. The paper will include performance results from several US generating stations operating either SCR and/or SNCR post combustion NO x systems. 16-5 Current Status of Development of Sieving Electrostatic Precipitator Hajrudin Pasic, Zahirul Khan, Ohio University, USA The paper describes a recently-proposed Sieving Electrostatic Precipitator (SEP)-- a device suitable for efficient, cost-effective cleaning of polluted gases of both large and ultra fine particulates in a very broad temperature range. In the last several years, a large number of fly ash collection-efficiency tests have been conducted, first on a bench-size SEP with 6-by-6 inches screens, at room temperature, high temperature (300-350°F), and several tests at 1500°F. Most recently, the SEP has been demonstrated in a laboratory pilot-scale setting with 6-by-2 foot screens at room temperature. All the results confirm that this technology provides high fly ash collection efficiency, including extremely efficient removal of ultra fine, submicron particulates. Finally, the joint effort of Ohio University (OU), Ohio Coal Research Office (OCDO), American Electric Power (AEP), and Electric Power Research Institute (EPRI) is in progress to build and test the SEP pilot unit as a part of a slipstream in AEP’s Conesville (OH) Power Plant. Some of those preliminary test results will be presented as well. SESSION 17 HYDROGEN FROM COAL: MEMBRANE SEPARATION 17-1 Dense Cermet Membranes for Hydrogen Separation from Mixed Gas Streams U. Balu Balachandran, Tae H. Lee, Ling Chen, Sun-Ju Song, Stephen E. Dorris, Argonne National Laboratory, USA The objective of this research project is to develop a novel single membrane reactor process that can consolidate two or more downstream unit operations of a coal gasification system in a single module for production of a pure stream of hydrogen and a pure stream of carbon dioxide. The overall goals are to achieve higher hydrogen production efficiencies, lower capital costs and a smaller overall footprint than what can be achieved by utilizing separate components for each required unit process/operation in conventional coal to hydrogen systems. This novel membrane reactor process that is under development combines hydrogen sulfide removal, hydrogen separation, carbon dioxide separation and water-gas shift reaction in a single membrane configuration. The carbon monoxide conversion of the water-gas-shift reaction from the coal derived syngas stream is enhanced by the complementary use of two membranes within a single reactor to separate hydrogen and carbon dioxide. Consequently, hydrogen production efficiency is increased. The single membrane reactor configuration produces a pure H 2 product and a pure CO 2 permeate stream that is ready for sequestration. In this work, Gas Technology Institute, partnered with Arizona State University, is evaluating the technical feasibility of this “one-box” concept by focusing on membrane material development. A new class of high-temperature nonporous membranes for separation of CO 2 from coal-derived syngas is being developed. Supported CO 2 membranes are synthesized using a variety of techniques, including in-situ impregnation and vacuum infiltration. Additionally, disc-shaped membranes are prepared by pressure compaction of precursor powders. The prepared membranes are analyzed for physical and chemical properties and evaluated for CO 2 permeation. This paper will discuss the simulation results for this novel single membrane reactor process in comparison with the conventional H 2 -selective or CO 2 -selective membrane reactor process. The modeling approach is based on thermodynamic analysis using a commercial flowsheet simulator to calculate the expected performances. The preliminary results from membrane synthesis and characterization will also be presented. The project is sponsored by DOE’s National Energy Technology Laboratory and Illinois Clean Coal Institute. 17-3 Alloy Membranes for Hydrogen Permeation Gokhan Alptekin, Sarah DeVoss, Robert Amalfitano, TDA Research, USA J. Dough Way, Paul Thoen, Mark Lusk, Colorado School of Mines, USA U.S. coal reserves nearly equal the total proved world conventional oil reserves – a 250-year supply of U.S. coal at today’s domestic production rates. Hydrogen represents a clean alternative fuel and its clean production from coal in tandem with carbon sequestration could reduce the environmental concerns associated with the widespread use of coal energy in stationary power applications. Gasification technologies have shown the potential to produce clean synthesis gas from coal with virtually zero pollutant emissions, including the emissions of carbon dioxide (CO 2 ). In this approach, coal is first gasified to produce a carbon monoxide (CO)-rich synthesis gas. In several processing steps the impurities in the syngas are removed and the CO content of the syngas is reduced by converting CO to hydrogen (H 2 ) in a two-step water-gas-shift reaction. Finally, the hydrogen is separated from other compounds, mainly CO, CO 2 and water. Currently, there are no coal-based facilities that produce both hydrogen and electric power. However, system level studies indicate that the efficiency of the coal-to-hydrogen plant could be enhanced if the WGS and H 2 separation were combined into a single step and carried out at temperatures compatible with the contaminant control step (350-400°C). The hydrogen separation membrane should provide robust performance, high hydrogen throughput, high selectivity and recovery and long-life at low cost. Palladium (Pd) alloy membranes have all these attributes. The hydrogen separation capability of Pd alloy membranes is well known with applications in hydrogenation/dehydrogenation reactions and recovery of hydrogen from petrochemical plant streams. Pd alloy membranes provide very 14
high selectivity (theoretically producing a 100% purity H 2 product). Unlike the ceramic membranes developed to date (which could only achieve up to 90% H 2 selectivity in a single pass and requires cascades of membrane modules to provide higher purities), Pd alloy membranes can achieve high selectivity in a single module. Pd alloy membranes also achieve very high hydrogen flux, with at least an order of magnitude higher flux than the high temperature dense ceramic membranes. The operating temperature of the Pd alloy membranes (300-600°C) is also well matched to that of the WGS process (200-600°C), where the reaction kinetics and the thermodynamic equilibrium both favor formation of hydrogen. The operating temperature for PSA systems (40-80°C) are too low for good WGS reaction kinetics and the equilibrium is unfavorable at the high operating temperature of the dense ceramic membranes (600-800°C). However, in spite of these potential benefits, several hurdles inhibit commercial implementation of this membrane technology. To be commercially viable: 1) the robustness of these membranes must be improved, 2) the cost of the membrane must be reduced, and 3) the sealing problems encountered when integrating the membrane into the process equipment must be eliminated; a key problem for any membrane system. TDA Research Inc., in collaboration with Colorado School of Mines (CSM) is developing a sulfur and CO-tolerant membrane to produce the clean hydrogen from syngas using Pd membrane films prepared on a variety of supports (e.g., symmetric ceramic supports and porous stainless steel supports). This paper summarizes the results of the membrane development and testing efforts. Membranes that showed superior properties in screening tests using hydrogen/nitrogen mixtures were further evaluated under representative conditions (the baseline gas composition used in these evaluations were 51% H 2 , 26% CO 2 , 21% H 2 O and 2% CO vol.). In general, membranes showed very good stability in water gas shift environment and were tested for several days with stable permeance and selectivity. We examined the effect of operating parameters including temperature, pressure and H 2 recovery on membrane performance. We also investigated the impact of CO, CO 2 and H 2 S concentration in the reformate gas on the H 2 permeation and selectivity of the membrane. 17-4 High-Pressure Operation of Dense Hydrogen Transport Membranes for Pure Hydrogen Production and Simultaneous CO 2 Capture Xiaobing Xie, Carl R. Everson IV, Michael V. Mundschau, Harold A. Wright, Paul J. Grimmer, Eltron Research Inc., USA Eltron has developed a family of dense inorganic membranes that enable high H 2 separation rates with essentially 100% selectivity to H 2 . The membranes are designed to operate at the same conditions as high-temperature water-gas shift (WGS) reactors (320−440°C) and can be operated with up to 1,000 psi pressure differential across the membrane. In synthesis gas systems that incorporate WGS, the membranes facilitate efficient, low cost separation of H 2 and CO 2 at high pressure, enabling efficient capture of CO 2 . The membranes are being developed to work with refinery waste streams as well as synthesis gas derived from natural gas, liquid hydrocarbons, coal, petroleum coke and biomass. The membranes may be ideal for natural gas or coal-based IGCC applications with or without hydrogen export. Compared to palladium-based membranes, the Eltron membrane exhibits 20 times the flux for a given set of conditions and costs about 10 times less. The high hydrogen permeability and low cost of the membrane materials allows the use of relatively thick membranes, which is crucial for their operation under high pressure differential. This technology has many advantages over competing hydrogen separation technologies. Advantages are listed as follows: (1) the membranes allow the capture of CO 2 at high pressure. The CO 2 is essentially captured at gasification or reforming pressure; (2) the membrane is low cost with long membrane life. Stability tests have been conducted for over eleven months on line with high flux retained; (3) the membranes, in principle, will work with synthesis gas generated from any source including coal, petroleum coke, natural gas, or biomass; (4) essentially 100% pure hydrogen is separated since the membrane works by transporting dissociated hydrogen across the membrane material; (5) hydrogen recoveries of 90% or higher are possible; (6) the membranes can be operated under high permeate pressures of pure hydrogen, and thus the costs associated with hydrogen compression can be substantially reduced; (7) the membranes can be integrated with commercial high temperature water-gas shift catalysts. The integrated membrane/WGS reactor has been demonstrated capable of achieving significantly higher CO conversion over the thermodynamic equilibrium limitation. Eltron was recently awarded a program from the United States Department of Energy aimed at scaling up these membranes for possible use in the FutureGen coal-based power and hydrogen plant. This paper discusses recent advances in the development of these membranes including experimental demonstrations of the above mentioned advantages, and membrane performance. 17-5 Effect of Nanocrystalline Catalysts on the Desorption Temperature of MgH 2 for Hydrogen Storage Applications M.S. Seehra, P. Dutta, S. Pal, J. Fortune, West Virginia University, USA MgH 2 is an attractive hydrogen storage material with 7.6 wt% hydrogen capacity and with a safe endothermic desorption of hydrogen at Td ≈ 4320°C [1]. However for practical applications, this Td is too high. In this work, we will report recent results of our experiments to lower Td. Our approach is based on the use of nanocrystalline Ni to reduce Td. Our recent experiments using 20 nm Ni nanoparticles mixed ultrasonically in the amount of 1 mol % with a commercial β-MgH 2 followed by ball milling of the mixture for 15 minutes, have yielded Td ≈ 2700°C as revealed by thermogravimetric analysis (TGA) and differential 15 scanning calorimetry (DSC). X-ray diffraction (XRD) of the sample at different stages of the reaction shows that sonicating alone shifts Td to 3400°C, without any chemical changes in Ni or β-MgH 2 . However, milling converts a part of β-MgH 2 to γ-MgH 2 . Additional experiments are underway to determine whether the lower Td ≈ 2700°C corresponds to γ- MgH 2 . From our experiments, it is also evident that lowering the crystalline size of both MgH 2 and the Ni catalyst and thorough mixing is likely to further reduce Td. An additional motivation to lower Td is to avoid the formation of Mg 2 Ni which in our experiments forms at 2700°C. This may be possible if the amount and crystallite size of the Ni catalyst are further reduced. Results of these experiments, now in progress, will be reported. * Work supported by U.S Department of Energy, Contract # DE-FC26-05NT42456. [1] See the review by J. Huot in Nanoclusters and Nanocrystals edited by H.S.Nalwa (Amer. Sci.Publishers, 2003) pages 53-85. SESSION 18 GLOBAL CLIMATE CHANGE: GREENHOUSE GAS UTILIZATION AND NOVEL CONCEPTS 18-1 Use of Coal Mine Methane in a Microturbine at CONSOL Energy’s Bailey Mine Deborah Kosmack, Richard A. Winschel, CONSOL Energy Inc., USA Patrick Rienks, Jay Johnson, Ingersoll-Rand Energy Systems, USA CONSOL Energy Inc Research & Development and Ingersoll Rand Energy Systems, with partial funding by the Clean Air Fund provided by the Pennsylvania Department of Environmental Protection, are installing a low-emission 70 kW microturbine generator on a large underground coal mine in Pennsylvania to reduce emissions of methane by capturing them and converting them into usable electricity. The generator will be fueled with coal mine methane that is currently being vented as part of the mine’s ventilation system. Coal mine methane is one of several major sources of anthropogenic methane, accounting for about 10% of anthropogenic methane emissions in the United States. Methane is the second most important non-water greenhouse gas, with a global warming potential 21 times as great as that of carbon dioxide (CO 2 ) on a mass basis. Thus, any coal mine methane that is emitted rather than utilized simultaneously represents a lost potential resource and the emission of a powerful greenhouse gas. The project objectives are to: 1) convert the low and variable concentrations of methane contained in coal mine methane gas that would otherwise be vented to the atmosphere to electricity; 2) provide the generated electric power to an existing electric power grid; 3) donate the value of the electricity generated during the project period to a local school district; and 4) determine the quantity of useful energy that can be economically produced when processing coal mine methane from a working coal mine and perform a techno-economic evaluation of the system. When operating at 95% capacity factor and a heat rate of 13,550 Btu/kWh HHV (higher heating value), the 70 kW generator will produce 583 MWh of electricity as it consumes 7,954,000 cubic feet of methane, with a global warming potential equivalent to 3,522 short tons of carbon dioxide, each year. Startup and commissioning of the system will be followed by 12 months of operations. 18-2 Green Power Technologies for High Ash Indian Coals-Evaluation of CO 2 Mitigation Options, D.N. Reddy, Centre for Energy Technology, INDIA; V.K. Sethi, Rajiv Gandhi Technological University, INDIA The Global concern for reduction in emission of green house gases (GHG) especially CO 2 emissions are likely to put pressure on Indian Power System for adoption of improved generation technologies. Although India does not have GHG reduction targets, it has actively taken steps to address the climate change issues. Mitigation options for CO 2 reduction which have been taken up vigorously include GHG emission reduction in power sector through adoption of Co-generation, Combined cycle, Clean Coal Technologies and Coal Beneficiation. CO 2 emissions per unit of electricity generated are significantly high in India as large proportion of power generated comes from low sized, old and relatively inefficient generating units which constitute over 50% of our total installed capacity of about 103,000 MW. The technology up gradation through life extension of old polluting units is expected to increase the generating efficiency of these units thereby reducing CO 2 emissions. Presently about 32 power stations with 106 units of various capacities ranging from 30MW to 200MW totaling to about 10,400 MW dated capacities are taken-up for Life extension (LE) during 10 th five year plan (2002-07). In addition to above about 60 Thermal Power plants units (13,900 MW) have been taken up for Renovation and Modernization (R&M) in the country, which is expected to contribute significantly in terms of CO 2 reduction. A major thrust on CO 2 reduction on long term and sustainable basis would however come through adoption of advanced technologies of power generation like Supercritical/Ultrasupercritical power cycles, Integrated Gasification Combined Cycles (IGCC), Fluidized Bed Combustion/Gasification Technologies and so on. A beginning towards adoption of super critical units has already been made in the country and it is foreseen that super critical technology would almost universally be adopted for all large sized pithead units in the country. The attained efficiency gains of these technologies are likely to reduce the environmental emissions especially CO 2 significantly. Adoption of higher parameters for super critical units after sufficient feedback and operational experience would further reduce these emissions to a great extent. A total additional efficiency of about 1.5-2% is normally
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: promising Clean Coal technologies u
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 and 52: POSTER SESSION 1 COMBUSTION TECHNOL
Page 53 and 54: experimental data available in lite
Page 55 and 56: activation. It was concluded that C

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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?