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Demonstration of oxygen-enriched combustion system on a light-duty vehicle to reduce cold-start emissions

Description: The oxygen content in the ambient air drawn by combustion engines can be increased by polymer membranes. The authors have previously demonstrated that 23 to 25% (concentration by volume) oxygen-enriched intake air can reduce hydrocarbons (HC), carbon monoxide (CO), air toxics, and ozone-forming potential (OFP) from flexible-fueled vehicles (FFVs) that use gasoline or M85. When oxygen-enriched air was used only during the initial start-up and warm-up periods, the emission levels of all three regulated pollutants [CO, nonmethane hydrocarbons (NMHC), and NO{sub x}] were lower than the U.S. EPA Tier II (year 2004) standards (without adjusting for catalyst deterioration factors). In the present work, an air separation membrane module was installed on the intake of a 2.5-L FFV and tested at idle and free acceleration to demonstrate the oxygen-enrichment concept for initial start-up and warm-up periods. A bench-scale, test set-up was developed to evaluate the air separation membrane characteristics for engine applications. On the basis of prototype bench tests and from vehicle tests, the additional power requirements and module size for operation of the membrane during the initial period of the cold-phase, FTP-75 cycle were evaluated. A prototype membrane module (27 in. long, 3 in. in diameter) supplying about 23% oxygen-enriched air in the engine intake only during the initial start-up and warm-up periods of a 2.5-L FFV requires additional power (blower) of less than one horsepower. With advances in air separation membranes to develop compact modules, oxygen enrichment of combustion air has the potential of becoming a more practical technique for controlling exhaust emissions from light-duty vehicles.
Date: August 1, 1997
Creator: Sekar, R. & Poola, R.B.
Partner: UNT Libraries Government Documents Department

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL

Description: Increased environmental regulations will require utility boilers to reduce NO{sub x} emissions to less than 0.15lb/MMBtu in the near term. Conventional technologies such as Selective Catalytic Reduction (SCR) and Selective Non-Catalytic Reduction (SNCR) are unable to achieve these lowered emission levels without substantially higher costs and major operating problems. Oxygen enhanced combustion is a novel technology that allows utilities to meet the NO{sub x} emission requirements without the operational problems that occur with SCR and SNCR. Furthermore, oxygen enhanced combustion can achieve these NO{sub x} limits at costs lower than conventional technologies. The objective of this program is to demonstrate the use of oxygen enhanced combustion as a technical and economical method of meeting the EPA State Implementation Plan for NO{sub x} reduction to less than 0.15lb/MMBtu for a wide range of boilers and coal. The oxygen enhanced coal combustion program (Task 1) focused this quarter on the specific objective of exploration of the impact of oxygen enrichment on NO{sub x} formation utilizing small-scale combustors for parametric testing. Research efforts toward understanding any limitations to the applicability of the technology to different burners and fuels such as different types of coal are underway. The objective of the oxygen transport membrane (OTM) materials development program (Task 2.1) is to ascertain a suitable material composition that can be fabricated into dense tubes capable of producing the target oxygen flux under the operating conditions. This requires that the material have sufficient oxygen permeation resulting from high oxygen ion conductivity, high electronic conductivity and high oxygen surface exchange rate. The OTM element development program (Task 2.2) objective is to develop, fabricate and characterize OTM elements for laboratory and pilot reactors utilizing quality control parameters to ensure reproducibility and superior performance. A specific goal is to achieve a material that will sinter to desired density ...
Date: July 1, 2000
Creator: Bool, Lawrence E.; Chen, Jack C. & Thompson, David R.
Partner: UNT Libraries Government Documents Department

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL

Description: This quarterly technical progress report will summarize work accomplished for the Program through the second quarter July--September 2000 in the following task areas: Task 1-Oxygen Enhanced Combustion, Task 2-Oxygen Transport Membranes and Task 4-Program Management. The program is proceeding in accordance with the objectives for the first year. OTM tube characterization is well underway, the design and assembly of the high pressure permeation test facility is complete and the facility will be in full operation during the next quarter. Combustion testing has been initiated at both the University of Arizona and Praxair. Testing at the University of Arizona has experienced some delays; steps have been take to get the test work back on schedule. Completion of the first phase of the testing is expected in next quarter. Combustion modeling has been started at both REI and Praxair, preliminary results are expected in the next quarter.
Date: October 1, 2000
Creator: Bool, Lawrence E.; Chen, Jack C. & Thompson, David R.
Partner: UNT Libraries Government Documents Department

Evaluation of oxygen-enrichment system for alternative fuel vehicles

Description: This report presents results on the reduction in exhaust emissions achieved by using oxygen-enriched intake air on a flexible fuel vehicle (FFV) that used Indolene and M85 as test fuels. The standard federal test procedure (FTP) and the US Environmental Protection Agency`s (EPA`s) off-cycle (REP05) test were followed. The report also provides a review of literature on the oxygen membrane device and design considerations. It presents information on the sources and contributions of cold-phase emissions to the overall exhaust emissions from light-duty vehicles (LDVs) and on the various emission standards and present-day control technologies under consideration. The effects of oxygen-enriched intake air on FTP and off-cycle emissions are discussed on the basis of test results. Conclusions are drawn from the results and discussion, and different approaches for the practical application of this technology in LDVs are recommended.
Date: December 1, 1995
Creator: Poola, R.B.; Sekar, R.R. & Ng, H.K.
Partner: UNT Libraries Government Documents Department

Demonstration of oxygen-enriched air staging at Owens-Brockway glass containers. Final technical report for the period April 1, 1995--February 28, 1997

Description: The overall objective of this program was to demonstrate the use of a previously developed combustion modification technology to reduce NO{sub x} emissions from sideport regenerative container glass melters. Specific objectives were to: acquire baseline operating data on the host sideport furnace, evaluate secondary oxidant injection strategies based on earlier endport furnace results and through modeling of a single port pair, retrofit and test one port pair (the test furnace has six port pairs) with a flexible OEAS system, and select the optimal system configuration, use the results from tests with one port pair to design, retrofit, and test OEAS on the entire furnace (six port pairs), and analyze test results, prepare report, and finalize the business plan to commercialize OEAS for sideport furnaces.
Date: October 1, 1997
Creator: Rue, D. & Abbasi, H.
Partner: UNT Libraries Government Documents Department

Optimal choice of cupola furnace nominal operating point

Description: One of the main goals in the operation of a cupola furnace is to keep the molten iron properties within prescribed bounds while maintaining the most economical operation for the cupola. In this paper the authors present a procedure to obtain the nominal values for the manipulated process variables. The nominal values are calculated by solving a constrained nonlinear programming optimization problem. Two different optimization problems are discussed and examples for using the procedure are presented.
Date: August 1, 1998
Creator: Abdelrahman, M.A. & Moore, K.L.
Partner: UNT Libraries Government Documents Department

Potential benefits of oxygen-enriched intake air in a vehicle powered by a spark-ignition engine

Description: A production vehicle powered by a spark-ignition engine (3.1-L Chevrolet Lumina, model year 1990) was tested. The test used oxygen-enriched intake air containing 25 and 28% oxygen by volume to determine (1) if the vehicle would run without difficulties and (2) if emissions benefits would result. Standard Federal Test Procedure (FTP) emissions test cycles were run satisfactorily. Test results of catalytic converter-out emissions (emissions out of the converter) showed that both carbon monoxide and hydrocarbons were reduced significantly in all three phases of the emissions test cycle. Test results of engine-out emissions (emissions straight out of the engine, with the converter removed) showed that carbon monoxide was significantly reduced in the cold phase. All emission test results were compared with those for normal air (21% oxygen). The catalytic converter also had an improved carbon monoxide conversion efficiency under the oxygen-enriched-air conditions. Detailed results of hydrocarbon speciation indicated large reductions in 1,3-butadiene, formaldehyde, acetaldehyde, and benzene from the engine with the oxygen-enriched air. Catalytic converter-out ozone was reduced by 60% with 25%-oxygen-content air. Although NO{sub x} emissions increased significantly, both for engine-out and catalytic converter-out emissions, we anticipate that they can be ameliorated in the near future with new control technologies. The automotive industry currently is developing exhaust-gas control technologies for an oxidizing environment; these technologies should reduce NO{sub x} emissions more efficiently in vehicles that use oxygen-enriched intake air. On the basis of estimates made from current data, several production vehicles that had low NO{sub x} emissions could meet the 2004 Tier II emissions standards with 25%-oxygen-content air.
Date: April 1, 1994
Creator: Ng, H. K. & Sekar, R. R.
Partner: UNT Libraries Government Documents Department

ADVANCED, LOW/ZERO EMISSION BOILER DESIGN AND OPERATION

Description: This document reviews the work performed during the quarter January-March 2003. The main objectives of the project are: To demonstrate the feasibility of the full-oxy combustion with flue gas recirculation on Babcock & Wilcox's 1.5MW pilot boiler, To measure its performances in terms of emissions and boiler efficiency while selecting the right oxygen injection strategies, To perform an economical feasibility study, comparing this solution with alternate technologies, and To design a new generation, full oxy-fired boiler. The main objective of this quarter was to initiate the project, primarily the experimental tasks. The contractor and its subcontractors have defined a working plan, and the first tasks have been started. Task 1 (Site Preparation) is now in progress, defining the modifications to be implemented to the boiler and oxygen delivery system. The changes are required in order to overcome some current limitations of the existing system. As part of a previous project carried out in 2002, several changes have already been made on the pilot boiler, including the enrichment of the secondary and tertiary air with oxygen or the replacement of these streams with oxygen-enriched recycled flue gas. A notable modification for the current project involves the replacement of the primary air with oxygen-enriched flue gas. Consequently, the current oxygen supply and flue gas recycle system is being modified to meet this new requirement. Task 2 (Combustion and Emissions Performance Optimization) has been initiated with a preliminary selection of four series of tests to be performed. So far, the project schedule is on-track: site preparation (Task 1) should be completed by August 1st, 2003 and the tests (Task 2) are planned for September-October 2003. The Techno-Economic Study (Task 3) will be initiated in the following quarter.
Date: April 1, 2003
Creator: Marin, Ovidiu & Chatel-Pelage, Fabienne
Partner: UNT Libraries Government Documents Department

AISI/DOE Technology Roadmap Program: Development of an O2-Enriched Furnace System for Reduced CO2 and NOx Emissions For the Steel Industry

Description: An oxygen-enriched furnace system for reduced CO2 and NOx emission has been developed. The furnace geometry, with a sidewall-mounted burner, was similar to configurations commonly encountered in a steel reheat furnace. The effect of stack oxygen concentration, oxygen enrichment level and air infiltration on fuel savings/CO2 reduction, NOx emissions and scale formation were investigated. The firing rate required to maintain the furnace temperature at 1100 C decreased linearly with increasing oxygen enrichment. At full oxygen enrichment a reduction of 40-45% in the firing rate was required to maintain furnace temperature. NOx emissions were relatively constant at oxygen enrichment levels below 60% and decreased concentration at all oxygen enrichment levels. Air infiltration also had an effect on NOx levels leading to emissions similar to those observed with no air infiltration but with similar stack oxygen concentrations. At high oxygen enrichment levels, there was a larger variation in the refractory surface-temperature on the roof and blind sidewall of the furnace. Scale habit, intactness, adhesion and oxidation rates were examined for five grades of steel over a range of stack oxygen concentrations and oxygen enrichment levels at 1100 degree C. The steel grade had the largest effect on scaling properties examined in this work. The stack oxygen concentration and the oxygen enrichment level had much smaller effects on the scaling properties.
Date: January 20, 2003
Creator: Grandmaison, Edward W.; Poirier, David J. & Boyd, Eric
Partner: UNT Libraries Government Documents Department

CERAMIC MEMBRANE ENABLING TECHNOLOGY FOR IMPROVED IGCC EFFICIENCY

Description: This quarterly technical progress report will summarize work accomplished for Phase 1 Program during the quarter April to June 2002. In task 1 improvements to the membrane material have shown increased flux, stability and strength. In task 2, composite development has demonstrated the ability to cycle membranes. In task 3, scale-up issues associated with manufacturing large elements have been identified and are being addressed. The work in task 4 has demonstrated that composite OTM elements can produce oxygen at greater than 95% purity after 10 thermal and pressure cycles. In task 5 the multi-tube OTM reactor has been operated and produced oxygen.
Date: August 1, 2002
Creator: Prasad, Ravi
Partner: UNT Libraries Government Documents Department

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL

Description: This quarterly technical progress report will summarize work accomplished for the Program through the ninth quarter April-June 2002 in the following task areas: Task 1--Oxygen Enhanced Combustion, Task 2--Oxygen Transport Membranes, Task 3--Economic Evaluation and Task 4--Program Management. The program is proceeding in accordance with the objectives for the third year. Full-scale testing using the Industrial Boiler Simulation Facility (ISBF) at Alstom Power was completed. The pilot scale experiments to evaluate the effect of air preheat and transport air stoichiometric ratio (SR) on NOx emissions were conducted at the University of Utah. Combustion modeling activities continued with full-scale combustion test furnace simulations. An OTM element was tested in Praxair's single tube high-pressure test facility and two thermal cycles were completed. PSO1d elements of new dimension were tested resulting in a lower flux than previous PSO1d elements of different dimensions, however, no element deformation was observed. Economic evaluation has confirmed the advantage of oxygen-enhanced combustion. Two potential host beta sites have been identified and proposals submitted.
Date: August 1, 2002
Creator: Thompson, David R.; Bool, Lawrence E. & Chen, Jack C.
Partner: UNT Libraries Government Documents Department

Study of using oxygen-enriched combustion air for locomotive diesel engines

Description: A thermodynamic simulation is used to study effects of O2-enriched intake air on performance and NO emissions of a locomotive diesel engine. Parasitic power of the air separation membrane required to supply the O2-enriched air is also estimated. For a given constraint on peak cylinder pressure, gross and net power output of an engine operating under different levels of O2 enrichment are compared with those obtained when a high-boost turbocharged engine is used. A 4% increase in peak cylinder pressure can result in 13% increase in net engine power when intake air with 28 vol% O2 is used and fuel injection timing retarded by 4 degrees. When the engine is turbocharged to a higher inlet boost, the same increase in peak cylinder pressure can result in only 4% improvement in power. If part of the higher exhaust enthalpies from the O2 enrichment is recovered, the power requirements of the air separator membrane can be met. O2 enrichment with its higher combustion temperatures reduces emissions of particulates and visible smoke but increases NO emissions (by up to 3 times at 26% O2 content). Therefore, exhaust gas after-treatment and heat recovery would be required if the full potential of O2 enrichment for improving the performance of locomotive diesel engines is to be realized.
Date: October 1, 1996
Creator: Poola, R.B.; Sekar, R.; Assanis, D.N. & Cataldi, G.R.
Partner: UNT Libraries Government Documents Department

Utilization of oxygen-enriched air in diesel engines: Fundamental considerations

Description: Utilization of oxygen-enriched air in diesel engines holds potential for low exhaust smoke and particulate emissions. The majority of the oxygen-enriched-air combustion-related studies so far are experimental in nature, where the observed results are understood on an overall basis. This paper deals with the fundamental considerations associated with the oxygen-enriched air-fuel combustion process to enhance understanding of the concept. The increase in adiabatic flame temperature, the composition of exhaust gases at equilibrium, and also the changes in thermodynamic and transport properties due to oxygen-enrichment of standard intake air are computed. The effects of oxygen-enrichment on fuel evaporation rate, ignition delay, and premixed burnt fraction are also evaluated. Appropriate changes in the ignition delay correlation to reflect the effects of oxygen-enrichment are proposed. The notion of oxygen-enrichment of standard intake air as being akin to leaning of the fuel-air mixture is refuted on the basis of the fundamentally different requirements for the oxygen-enriched combustion process.
Date: September 1, 1997
Creator: Lahiri, D.; Mehta, P.S.; Poola, R.B. & Sekar, R.
Partner: UNT Libraries Government Documents Department

Evaluation of Pure Oxygen Systems at the Umatilla Hatchery: Task 1-Review and Evaluation of Supplemental O2 Systems, Final Report.

Description: The Northwest Power Planning Council has established a goal of doubling the size of salmon runs in the Columbia River Basin. The achievement of this important goal is largely dependent upon expanding the production of hatchery fish. Pure oxygen has been commonly used to increase the carrying capacity of private sector salmonid hatcheries in the Pacific Northwest. The use of supplemental oxygen to increase hatchery production is significantly less expensive than the construction of new hatcheries and might save up to $500 million in construction costs.
Date: March 1991
Creator: Fish Factory
Partner: UNT Libraries Government Documents Department

Treatment of geothermal condensate to reduce iron chelate consumption. Geothermal power initiative final report, September 30, 1997--March 31, 1998

Description: A portable oxygen generator was constructed and emission tests were run by injecting oxygen into the main steam line. H{sub 2}S was measured before and after oxygen injection, and the iron concentration was monitored with oxygen and air oxidation systems in service and then with oxygen in service and air oxidation out of service. Results were not favorable in either case.
Date: January 1, 1998
Creator: Bahning, T.
Partner: UNT Libraries Government Documents Department

Utilizing intake-air oxygen-enrichment technology to reduce cold- phase emissions

Description: Oxygen-enriched combustion is a proven, serious considered technique to reduce exhaust hydrocarbons (HC) and carbon monoxide (CO) emissions from automotive gasoline engines. This paper presents the cold-phase emissions reduction results of using oxygen-enriched intake air containing about 23% and 25% oxygen (by volume) in a vehicle powered by a spark-ignition (SI) engine. Both engineout and converter-out emissions data were collected by following the standard federal test procedure (FTP). Converter-out emissions data were also obtained employing the US Environmental Protection Agency`s (EPA`s) ``Off-Cycle`` test. Test results indicate that the engine-out CO emissions during the cold phase (bag 1) were reduced by about 46 and 50%, and HC by about 33 and 43%, using nominal 23 and 25% oxygen-enriched air compared to ambient air (21% oxygen by volume), respectively. However, the corresponding oxides of nitrogen (NO{sub x}) emissions were increased by about 56 and 79%, respectively. Time-resolved emissions data indicate that both HC and CO emissions were reduced considerably during the initial 127 s of the cold-phase FTP, without any increase in NO, emissions in the first 25 s. Hydrocarbon speciation results indicate that all major toxic pollutants, including ozone-forming specific reactivity factors, such as maximum incremental reactivity (NUR) and maximum ozone incremental reactivity (MOIR), were reduced considerably with oxygen-enrichment. Based on these results, it seems that using oxygen-enriched intake air during the cold-phase FTP could potentially reduce HC and CO emissions sufficiently to meet future emissions standards. Off-cycle, converter-out, weighted-average emissions results show that both HC and CO emissions were reduced by about 60 to 75% with 23 or 25% oxygen-enrichment, but the accompanying NO{sub x}, emissions were much higher than those with the ambient air.
Date: December 31, 1995
Creator: Poola, R.B.; Ng, H.K.; Sekar, R.R.; Baudino, J.H. & Colucci, C.P.
Partner: UNT Libraries Government Documents Department

OXYGEN TRANSPORT CERAMIC MEMBRANES

Description: In the present quarter, oxygen transport perovskite ceramic membranes are evaluated for strength and fracture in oxygen gradient conditions. Oxygen gradients are created in tubular membranes by insulating the inner surface from the reducing environment by platinum foils. Fracture in these test conditions is observed to have a gradient in trans and inter-granular fracture as opposed to pure trans-granular fracture observed in homogeneous conditions. Fracture gradients are reasoned to be due to oxygen gradient set up in the membrane, variation in stoichiometry across the thickness and due to varying decomposition of the parent perovskite. The studies are useful in predicting fracture criterion in actual reactor conditions and in understanding the initial evolution of fracture processes.
Date: July 1, 2002
Creator: Bandopadhyay, Dr. Sukumar & Nagabhushana, Dr. Nagendra
Partner: UNT Libraries Government Documents Department

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL

Description: This quarterly technical progress report will summarize work accomplished for the Program in the seventh quarter October-December 2001 in the following task areas: Task 1 - Oxygen Enhanced Combustion, Task 2 - Oxygen Transport Membranes, Task 3 - Economic Evaluation and Task 4 - Program Management. Computational fluid dynamic (CFD) modeling of oxygen injection strategies was performed during the quarter resulting in data that suggest the oxygen injection reduces NOx emissions while reducing LOI. Pilot-scale testing activities concluded at the University of Utah this quarter. Testing demonstrated that some experimental conditions can lead to NOx emissions well below the 0.15 lb/MMBtu limit. Evaluation of alternative OTM materials with improved mechanical properties continued this quarter. Powder procedure optimization continued and sintering trial began on an element with a new design. Several OTM elements were tested in Praxair's single tube high-pressure test facility under various conditions. A modified PSO1d element demonstrated stable oxygen product purity of >98% and oxygen flux of 68% of target. Updated test results and projected economic performance have been reviewed with the Utility Industrial Advisors. The economic comparison remains very favorable for O{sub 2} enhanced combustion. Discussions regarding possible Beta sites have been held with three other utilities in addition to the industrial advisors. Proposals will be prepared after the completion of full scale burner testing. Beta test cost estimating work has been initiated.
Date: January 1, 2002
Creator: Thompson, David R.; Bool, Lawrence E. & Chen, Jack C.
Partner: UNT Libraries Government Documents Department

CERAMIC MEMBRANE ENABLING TECHNOLOGY FOR IMPROVED IGCC EFFICIENCY

Description: The objective of this program is to conduct a technology development program to advance the state-of-the-art in ceramic Oxygen Transport Membranes (OTM) to the level required to produce step change improvements in process economics, efficiency, and environmental benefits for commercial IGCC systems and other applications. The IGCC program is focused on addressing key issues in materials, processing, manufacturing, engineering and system development that will make the OTM a commercial reality. The objective of the OTM materials development task is to identify a suitable material that can be formed into a thin film to produce the target oxygen flux. This requires that the material have an adequate permeation rate, and thermo-mechanical and thermo-chemical properties such that the material is able to be supported on the desired substrate and sufficient mechanical strength to survive the stresses involved in operation. The objective of the composite OTM development task is to develop the architecture and fabrication techniques necessary to construct stable, high performance, thin film OTMs supported on suitable porous, load bearing substrates. The objective of the process development task of this program to demonstrate the program objectives on a single OTM tube under test conditions simulating those of the optimum process cycle for the power plant. Good progress has been made towards achieving the DOE-IGCC program objectives. Two promising candidates for OTM materials have been identified and extensive characterization will continue. New compositions are being produced and tested which will determine if the material can be further improved in terms of flux, thermo-mechanical and thermo-chemical properties. Process protocols for the composite OTM development of high quality films on porous supports continues to be optimized. Dense and uniform PSO1 films were successfully applied on porous disc and tubular substrates with good bonding between the films and substrates, and no damage to the substrates or ...
Date: April 1, 2000
Creator: Prasad, Ravi
Partner: UNT Libraries Government Documents Department

Experimental evaluation of oxygen-enriched air and emulsified fuels in a single-cylinder diesel engine. Volume 2, Data sets

Description: This report contains the data gathered from tests conducted on a single-cylinder diesel engine to study the benefits and problems of oxygen-enriched diesel combustion and the use of water-emulsified and low-grade diesel fuels. This research, funded by the Office of Industrial Technologies (OIT) in the United States Department of Energy, is being conducted in support of the Industrial Cogeneration Program. The report is made up of two volumes. Volume 1 contains the description of the experiments, selected data points, discussion of trends, and conclusions and recommendations; Volume 2 contains the data sets. With the two-volume approach, readers can find information at the desired level of detail, depending on individual interest or need.
Date: November 1, 1991
Creator: Sekar, R. R.; Marr, W. W.; Cole, R. L. & Marciniak, T. J.
Partner: UNT Libraries Government Documents Department

Experimental Evaluation of Oxygen-Enriched Air and Emulsified Fuels in a Single-Cylinder Diesel Engine. Volume 1, Concept Evaluation

Description: The performance of a single-cylinder, direct-injection diesel engine was measured with intake oxygen levels of up to 35% and fuel water contents of up to 20%. Because a previous study indicated that the use of a less-expensive fuel would be more economical, two series of tests with No. 4 diesel fuel and No. 2 diesel fuel were conducted. To control the emissions of nitrogen oxides (NO{sub x}), water was introduced into the combustion process in the form of water-emulsified fuel, or the fuel injection timing was retarded. In the first series of tests, compressed oxygen was used; in the second series of tests, a hollow-tube membrane was used. Steady-state engine performance and emissions data were obtained. Test results indicated a large increase in engine power density, a slight improvement in thermal efficiency, and significant reductions in smoke and particulate-matter emissions. Although NO{sub x} emissions increased, they could be controlled by introducing water and retarding the injection timing. The results further indicated that thermal efficiency is slightly increased when moderately water-emulsified fuels are used, because a greater portion of the fuel energy is released earlier in the combustion process. Oxygen-enriched air reduced the ignition delay and caused the heat-release rate and cumulative heat-release rates to change measurably. Even at higher oxygen levels, NO{sub x} emissions decreased rapidly when the timing was retarded, and the amount of smoke and the level of particulate-matter emissions did not significantly increase. The single-cylinder engine tests confirmed the results of an earlier technical assessment and further indicated a need for a low-pressure-drop membrane specifically designed for oxygen enrichment. Extension data set indexed separately. 14 refs.
Date: November 1, 1991
Creator: Sekar, R. R.; Marr, W. W.; Cole, R. L. & Marciniak, T. J.
Partner: UNT Libraries Government Documents Department