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Establishing an energy efficiency recommendation for commercial boilers

Description: To assist the federal government in meeting its energy reduction goals, President Clinton's Executive Order 12902 established the Procurement Challenge, which directed all federal agencies to purchase equipment within the top 25th percentile of efficiency. Under the direction of DOE's Federal Energy Management Program (FEMP), the Procurement Challenge's goal is to create efficiency recommendations for all energy-using products that could substantially impact the government's energy reduction goals, like commercial boilers. A typical 5,000,000 Btuh boiler, with a thermal efficiency of 83.2%, can have lifetime energy cost savings of $40,000 when compared to a boiler with a thermal efficiency of 78%. For the federal market, which makes up 2% of the boiler market, this means lifetime energy cost savings of over $25,600,000. To establish efficiency recommendations, FEMP uses standardized performance ratings for products sold in the marketplace. Currently, the boiler industry uses combustion efficiency and, sometimes, thermal efficiency performance measures when specifying a commercial boiler. For many years, the industry has used these efficiency measures interchangeably, causing confusion about boiler performance measurements, and making it difficult for FEMP to establish the top 25th percentile of efficiency. This paper will illustrate the method used to establish FEMP's recommendation for boilers. The method involved defining a correlation between thermal and combustion efficiency among boiler classifications; using the correlation to model a data set of all the boiler types available in the market; and identifying how the correlation affected the top 25th percentile analysis. The paper also will discuss the applicability of this method for evaluating other equipment for which there are limited data on performance ratings.
Date: August 1, 2000
Creator: Ware, Michelle J.
Partner: UNT Libraries Government Documents Department

Heavy Truck Clean Diesel Cooperative Research Program

Description: This report is the final report for the Department of Energy on the Heavy Truck Engine Program (Contract No. DE-FC05-00OR22806) also known as Heavy Truck Clean Diesel (HTCD) Program. Originally, this was scoped to be a $38M project over 5 years, to be 50/50 co-funded by DOE and Caterpillar. The program started in June 2000. During the program the timeline was extended to a sixth year. The program completed in December 2006. The program goal was to develop and demonstrate the technologies required to enable compliance with the 2007 and 2010 (0.2g/bhph NOx, 0.01g/bhph PM) on-highway emission standards for Heavy Duty Trucks in the US with improvements in fuel efficiency compared to today's engines. Thermal efficiency improvement from a baseline of 43% to 50% was targeted.
Date: December 31, 2006
Creator: Milam, David
Partner: UNT Libraries Government Documents Department

Development of the Radiation Stabilized Distributed Flux Burner, Phase II Final Report

Description: This report covers progress made during Phase 2 of a three-phase DOE-sponsored project to develop and demonstrate the Radiation Stabilized Distributed Flux burner (also referred to as the Radiation Stabilized Burner, or RSB) for use in industrial watertube boilers and process heaters. The goal of the DOE-sponsored work is to demonstrate an industrial boiler burner with NOx emissions below 9 ppm and CO emissions below 50 ppm (corrected to 3% stack oxygen). To be commercially successful, these very low levels of NOx and CO must be achievable without significantly affecting other measures of burner performance such as reliability, turndown, and thermal efficiency. Phase 1 of the project demonstrated that sub-9 ppm NOx emissions and sub-50 ppm CO emissions (corrected to 3% oxygen) could be achieved with the RSB in a 3 million Btu/Hr laboratory boiler using several methods of NOx reduction. The RSB was also tested in a 60 million Btu/hr steam generator used by Chevron for Thermally Enhanced Oil Recovery (TEOR). In the larger scale tests, fuel staging was demonstrated, with the RSB consistently achieving sub-20 ppm NOx and as low as 10 ppm NOx. Large-scale steam generator tests also demonstrated that flue gas recirculation (FGR) provided a more predictable and reliable method of achieving sub-9 ppm NOx levels. Based on the results of tests at San Francisco Thermal and Chevron, the near-term approach selected by Alzeta for achieving low NOx is to use FGR. This decision was based on a number of factors, with the most important being that FGR has proved to be an easier approach to transfer to different facilities and boiler designs. In addition, staging has proved difficult to implement in a way that allows good combustion and emissions performance in a fully modulating system. In Phase 3 of the project, the RSB will be ...
Date: June 1, 1997
Creator: Webb, A. & Sullivan, J.D.
Partner: UNT Libraries Government Documents Department

The effect of air infiltration on the thermal performance of a small metal-framed assembly

Description: Innovative construction materials and systems have generated a need for laboratory scale tests to quantify the effect of air leakage on thermal and moisture performance of building assemblies. Some construction materials and systems are inherently more air tight than others. It is desirable to do laboratory scale measurements on alternative systems so as to rank them with respect to air tightness just as they can be ranked with respect to system R-value. Participants in summer 1995 and 1996 workshops for elementary and secondary school science teachers in the Buildings Technology Center (BTC) at the Oak Ridge National Laboratory sought a way to illustrate basic principles of building science in the classroom. They decided to build a small metal-framed assembly with internal volume of 44 ft{sup 3} (1.25 m{sup 3}) and removable wall sheathing. The assembly included a door and window. Although the door and window were made from 4-in. (10.2-cm) thick foam insulation, the requisite framing for them detracted from the thermal performance of the walls and occupied a disproportionately large fraction of the wall area. The floor and roof of the assembly were also well-insulated so that the walls dominated the conduction heat loss through the assembly. The plan was to test thermal performance of the assembly with the sheathing and without it. Thereby the teachers hoped to show the effects of thermal bridges with metal framing as well as practical yet insightful way to reduce their effects.
Date: March 1997
Creator: Petrie, T. W.; Christian, J. E. & Childs, P. W.
Partner: UNT Libraries Government Documents Department

Evaluation of Gas Reburning and Low-NOx Burners on a Wall-Fired Boiler; a DOE Assessment

Description: The results from the GR-LNB technology demonstrated by EER at Cherokee Station approached, but did not meet, the CCT project's performance objectives. Acceptable unit operability was achieved with both the GR and the LNB components. The gas reburning component of the process appears to be broadly applicable for retrofit NO{sub x} control to most utility boilers and, in particular, to wet-bottom cyclone boilers, which are high NO{sub x} emitters and are difficult to control (LNB technology is not applicable to cyclone boilers). GR-LNB can reduce NO{sub x} to mandated emissions levels under Title IV of the CAAA without significant, adverse boiler impacts. The GR-LNB process may be applicable to boilers significantly larger than the demonstration unit, provided there is adequate dispersion and mixing of injected natural gas. Major results of the demonstration project are summarized as follows: NO{sub x}-emissions reductions averaging 64% were achieved with 12.5% gas heat input in long-term tests on a 158-MWe (net) wall-fired unit. The target reduction level of 70% was achieved only on a short-term basis with higher gas consumption. The thermal performance of coal-fired boilers is not significantly affected by GR-LNB. Convective section steam temperatures can be controlled within acceptable limits. Thermal efficiency is decreased by a small amount (about 0.8%), because of increased dry gas loss and higher moisture in the flue gas as a result of the GR process. Furnace slagging and convective section fouling can be adequately controlled. Because of the higher hydrogen/carbon (H/C) ratio of natural gas compared with coal, use of the GR process results in a modest reduction in CO{sub 2} emissions. SO{sub 2} and particulate emissions are reduced in direct proportion to the fraction of heat supplied by natural gas.
Date: February 28, 2001
Creator: National Energy Technology Laboratory (U.S.)
Partner: UNT Libraries Government Documents Department

A new look at moisture control in low slope roofing

Description: One of the criteria for a moisture-tolerant roof is that moisture accumulation in a roofing system must not be large enough to cause condensation within the roof, since this can damage the insulation and reduce its effectiveness. Failing this criterion would require the inclusion of a vapor retarder into the roofing system. We have tested this requirement using computer simulations for a series of new roofing systems and environmental conditions. This paper uses the database from those simulations to develop a simplified method to predict condensation control using only variables associated with the roof and environmental conditions. This method assesses the potential for condensation within the roof assembly without having to perform a computer simulation. Using the computer simulation output data, the moisture accumulation inside each of the roofing systems was calculated. A critical threshold of moisture accumulation was assigned by analyzing the roofing systems which fail to prevent condensation from occurring within the roofing system. An empirical equation for moisture accumulation as a function of roof system and environmental condition variables is developed. The moisture accumulation calculated using this relationship correlates well with the moisture accumulation based on the results of computer simulations. The ability of these two different relationships for moisture accumulation to predict condensation control using the established critical threshold is assessed. Accuracy of both methods is over 95%.
Date: March 1, 1997
Creator: Desjarlais, A.O. & Byars, N.A.
Partner: UNT Libraries Government Documents Department

Thermal Barrier Coatings for Low Emission, High Efficiency Diesel Engine Applications

Description: Thermal efficiencies of 54% have been demonstrated by single cylinder engine testing of advanced diesel engine concepts developed under Department of Energy funding. In order for these concept engines to be commercially viable, cost effective and durable systems for insulating the piston, head, ports and exhaust manifolds will be required. The application and development of new materials such as thick thermal barrier coating systems will be key to insulating these components. Development of test methods to rapidly evaluate the durability of coating systems without expensive engine testing is a major objective of current work. In addition, a novel, low cost method for producing thermal barrier coated pistons without final machining of the coating has been developed.
Date: April 26, 1999
Creator: Beardsley, M. B.; Happoldt, P. G.; Kelley, K.C.; Rejda, E. F. & Socie, D. F.
Partner: UNT Libraries Government Documents Department

Performance of Charcoal Cookstoves for Haiti Part 1: Results from the Water Boiling Test

Description: In April 2010, a team of scientists and engineers from Lawrence Berkeley National Lab (LBNL) and UC Berkeley, with support from the Darfur Stoves Project (DSP), undertook a fact-finding mission to Haiti in order to assess needs and opportunities for cookstove intervention. Based on data collected from informal interviews with Haitians and NGOs, the team, Scott Sadlon, Robert Cheng, and Kayje Booker, identified and recommended stove testing and comparison as a high priority need that could be filled by LBNL. In response to that recommendation, five charcoal stoves were tested at the LBNL stove testing facility using a modified form of version 3 of the Shell Foundation Household Energy Project Water Boiling Test (WBT). The original protocol is available online. Stoves were tested for time to boil, thermal efficiency, specific fuel consumption, and emissions of CO, CO{sub 2}, and the ratio of CO/CO{sub 2}. In addition, Haitian user feedback and field observations over a subset of the stoves were combined with the experiences of the laboratory testing technicians to evaluate the usability of the stoves and their appropriateness for Haitian cooking. The laboratory results from emissions and efficiency testing and conclusions regarding usability of the stoves are presented in this report.
Date: June 1, 2011
Creator: Booker, Kayje; Han, Tae Won; Granderson, Jessica; Jones, Jennifer; Lsk, Kathleen; Yang, Nina et al.
Partner: UNT Libraries Government Documents Department

Development of the Hybrid Sulfur Thermochemical Cycle

Description: The production of hydrogen via the thermochemical splitting of water is being considered as a primary means for utilizing the heat from advanced nuclear reactors to provide fuel for a hydrogen economy. The Hybrid Sulfur (HyS) Process is one of the baseline candidates identified by the U.S. Department of Energy [1] for this purpose. The HyS Process is a two-step hybrid thermochemical cycle that only involves sulfur, oxygen and hydrogen compounds. Recent work has resulted in an improved process design with a calculated overall thermal efficiency (nuclear heat to hydrogen, higher heating value basis) approaching 50%. Economic analyses indicate that a nuclear hydrogen plant employing the HyS Process in conjunction with an advanced gas-cooled nuclear reactor system can produce hydrogen at competitive prices. Experimental work has begun on the sulfur dioxide depolarized electrolyzer, the major developmental component in the cycle. Proof-of-concept tests have established proton-exchange-membrane cells (a state-of-the-art technology) as a viable approach for conducting this reaction. This is expected to lead to more efficient and economical cell designs than were previously available. Considerable development and scale-up issues remain to be resolved, but the development of a viable commercial-scale HyS Process should be feasible in time to meet the commercialization schedule for Generation IV gas-cooled nuclear reactors.
Date: September 23, 2005
Creator: Summers, William A. & Steimke, John L
Partner: UNT Libraries Government Documents Department


Description: Two hybrid sulfur (HyS) cycle process flowsheets intended for use with high-temperature gas-cooled reactors (HTGRs) are presented. The flowsheets were developed for the Next Generation Nuclear Plant (NGNP) program, and couple a proton exchange membrane (PEM) electrolyzer for the SO2-depolarized electrolysis step with a silicon carbide bayonet reactor for the high-temperature decomposition step. One presumes an HTGR reactor outlet temperature (ROT) of 950 C, the other 750 C. Performance was improved (over earlier flowsheets) by assuming that use of a more acid-tolerant PEM, like acid-doped poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (PBI), instead of Nafion{reg_sign}, would allow higher anolyte acid concentrations. Lower ROT was accommodated by adding a direct contact exchange/quench column upstream from the bayonet reactor and dropping the decomposition pressure. Aspen Plus was used to develop material and energy balances. A net thermal efficiency of 44.0% to 47.6%, higher heating value basis is projected for the 950 C case, dropping to 39.9% for the 750 C case.
Date: July 6, 2011
Creator: Gorensek, M.
Partner: UNT Libraries Government Documents Department

Under-sampling in a Multiple-Channel Laser Vibrometry System

Description: Laser vibrometry is a technique used to detect vibrations on objects using the interference of coherent light with itself. Most vibrometry systems process only one target location at a time, but processing multiple locations simultaneously provides improved detection capabilities. Traditional laser vibrometry systems employ oversampling to sample the incoming modulated-light signal, however as the number of channels increases in these systems, certain issues arise such a higher computational cost, excessive heat, increased power requirements, and increased component cost. This thesis describes a novel approach to laser vibrometry that utilizes undersampling to control the undesirable issues associated with over-sampled systems. Undersampling allows for significantly less samples to represent the modulated-light signals, which offers several advantages in the overall system design. These advantages include an improvement in thermal efficiency, lower processing requirements, and a higher immunity to the relative intensity noise inherent in laser vibrometry applications. A unique feature of this implementation is the use of a parallel architecture to increase the overall system throughput. This parallelism is realized using a hierarchical multi-channel architecture based on off-the-shelf programmable logic devices (PLDs).
Date: August 15, 2006
Creator: Corey, J
Partner: UNT Libraries Government Documents Department

Advanced Turbine Systems (ATS) program conceptual design and product development. Quarterly report, August 25--November 30, 1993

Description: GE has achieved a leadership position in the worldwide gas turbine industry in both industrial/utility markets and in aircraft engines. This design and manufacturing base plus our close contact with the users provides the technology for creation of the next generation advanced power generation systems for both the industrial and utility industries. GE has been active in the definition of advanced turbine systems for several years. These systems will leverage the technology from the latest developments in the entire GE gas turbine product line. These products will be USA based in engineering and manufacturing and are marketed through the GE Industrial and Power Systems. Achieving the advanced turbine system goals of 60% efficiency, 8 ppmvd NOx and 10% electric power cost reduction imposes competing characteristics on the gas turbine system. Two basic technical issues arise from this. The turbine inlet temperature of the gas turbine must increase to achieve both efficiency and cost goals. However, higher temperatures move in the direction of increased NOx emission. Improved coating and materials technologies along with creative combustor design can result in solutions to achieve the ultimate goal.
Date: June 1, 1997
Partner: UNT Libraries Government Documents Department

Prospectus of ignition enhancement in a two-stroke SI engine

Description: Conventional two-stroke spark-ignition (SI) engines have difficulty meeting the ignition requirements of lean fuel-air mixtures and high compression ratios, due to their breaker operated, magneto-coil ignition systems. In the present work, a breakerless, high-energy electronic ignition system was developed and tested with and without a platinum-tipped electrode spark plug. The high-energy ignition system showed an improved lean-burn capability at high compression ratios relative to the conventional ignition system. At a high compression ratio of 9:1 with lean fuel-air mixtures, the maximum percentage improvement in the brake thermal efficiency was about 16.5% at 2.7 kW and 3000 rpm. Cylinder peak pressures-were higher ignition delay was lower, and combustion duration was shorter at both normal and high compression ratios. Combustion stability as measured by the coefficient of variation in peak cylinder pressure was also considerably improved with the high-energy ignition system.
Date: December 1, 1995
Creator: Manivannan, P.V.; Ramesh, A.; Poola, R.B. & Dhinadgar, S.J.
Partner: UNT Libraries Government Documents Department

Development and demonstration of a wood-fired gas turbine system

Description: Power Generating Inc. (PGI) has developed and patented a unique direct-fired gas turbine power system (PGI Power System) that operates on solid wood-based fuels. The PGI Power System is designed to generate from 500 kilowatts to 3.5 megawatts of electrical power and up to 30 million Btu per hour of thermal energy for various industrial and utility applications. The system is expected to operate at thermal efficiency levels greater than 70% through full utilization of both the electrical and thermal energy it generates at a specific host facility. PGI and WRI built a 450-kW prototype system at the Western Research Institute (WRI) facilities in Laramie, Wyoming, to demonstrate the technical and economic viability of the PGI Power System. The plant has undergone a brief shakedown, and is presently being operated on white wood. In previous attempts to develop similar systems, the major technical hindrance to long-term operation of a gas turbine power system has been degradation of the hot section in the gas turbine. This problem is overcome in the PGI Power System through its unique design, by closely controlling fuel specifications, and by developing specialized operating procedures. In wood-fired testing conducted to date, no degradation in the engine performance is obvious.
Date: October 1, 1997
Creator: Sethi, V.
Partner: UNT Libraries Government Documents Department

Coal-water slurry fuel combustion testing in an oil-fired industrial boiler. Semi-annual technical progress report, 15 August 1995--15 February 1996

Description: The Pennsylvania State University is conducting a coal-water slurry fuel (CWSF) program with the US Department of Energy (DOE) and the Commonwealth of Pennsylvania to determine the viability of firing CWSF in an industrial boiler designed for heavy fuel oil. Penn State and DOE have entered into a cooperative agreement to determine if CWSFs prepared from cleaned coal (containing approximately 3.5 wt.% ash and 0.9 wt.% sulfur) can be burned effectively in a heavy fuel oil-designed industrial boiler without adverse impact on boiler rating, maintainability, reliability, and availability. Information will also be generated to help in the design of new systems specifically configured to fire these clean coal-based fuels. The project consists of four phases: (1) design, permitting, and test planning, (2) construction and start up, (3) demonstration and evaluation (1,000-hour demonstration), and (4) expanded demonstration and evaluation (installing a CWSF preparation circuit, performing baseline tests firing No. 6 fuel oil, and conducting additional CWSF testing). The first three phases (i.e., the first 1,000-hour demonstration) have been completed and the combustion performance of the burner that was provided with the boiler did not meet performance goals. A maximum coal combustion efficiency of 95% (compared to a target of 98%) was achieved and natural gas cofiring (15% of the total thermal input) was necessary to maintain a stable flame. Consequently, the first demonstration was terminated after 500 hours. The second CWSF demonstration (Phase 4) will be conducted with a proven CWSF-designed burner. Prior to starting the second demonstration, a CWSF preparation circuit was constructed to provide flexibility in CWSF production. The circuit initially installed involved single-stage grinding. A regrid circuit was recently installed and will be evaluated. A burner was installed from ABB Combustion Engineering (ABB/CE) and will be used to generate baseline data firing No. 6 fuel oil and CWSF. ...
Date: June 3, 1997
Creator: Miller, B.G. & Scaroni, A.W.
Partner: UNT Libraries Government Documents Department

Development of Integrated Motor Assist Hybrid System: Development of the 'Insight', a Personal Hybrid Coupe

Description: This paper presents the technical approach used to design and develop the powerplant for the Honda Insight, a new motor assist hybrid vehicle with an overall development objective of just half the fuel consumption of the current Civic over a wide range of driving conditions. Fuel consumption of 35km/L (Japanese 10-15 mode), and 3.4L/100km (98/69/EC) was realized. To achieve this, a new Integrated Motor Assist (IMA) hybrid power plant system was developed, incorporating many new technologies for packaging and integrating the motor assist system and for improving engine thermal efficiency. This was developed in combination with a new lightweight aluminum body with low aerodynamic resistance. Environmental performance goals also included the simultaneous achievement of low emissions (half the Japanese year 2000 standards, and half the EU2000 standards), high efficiency, and recyclability. Full consideration was also given to key consumer attributes, including crash safety performance, handling, and driving performance.
Date: June 19, 2000
Creator: Aoki, Kaoru; Kuroda, Shigetaka; Kajiwara, Shigemasa; Sato, Hiromitsu & Yamamoto, Yoshio
Partner: UNT Libraries Government Documents Department

Development of METHANE de-NOX reburning process. Quarterly report, October 1 - December 31, 1999

Description: The use of biomass and wood waste solids and sludges as fuel is often hampered by their low heating values and the presence of bound nitrogen that result in inefficient combustion and high NOx emission. Cofiring supplemental fuel through auxiliary burners helps with improving the combustion effectiveness and NOx reduction, but the benefits are limited to the fractional heat input of the auxiliary fuel. Demonstration tests have shown over 60% reduction in NOx, CO and VOC emissions, and a 2% increase in boiler thermal efficiency using only 8 to 13% natural gas.
Date: December 31, 1999
Partner: UNT Libraries Government Documents Department

H gas turbine combined cycle

Description: A major step has been taken in the development of the Next Power Generation System--``H`` Technology Combined Cycle. This new gas turbine combined-cycle system increases thermal performance to the 60% level by increasing gas turbine operating temperature to 1,430 C (2,600 F) at a pressure ratio of 23 to 1. Although this represents a significant increase in operating temperature for the gas turbine, the potential for single digit NOx levels (based upon 15% O{sub 2}, in the exhaust) has been retained. The combined effect of performance increase and environmental control is achieved by an innovative closed loop steam cooling system which tightly integrates the gas turbine and steam turbine cycles. The ``H`` Gas Turbine Combined Cycle System meets the goals and objectives of the DOE Advanced Turbine System Program. The development and demonstration of this new system is being carried out as part of the Industrial/Government cooperative agreement under the ATS Program. This program will achieve first commercial operation of this new system before the end of the century.
Date: December 31, 1995
Creator: Corman, J.
Partner: UNT Libraries Government Documents Department

ALPS - advanced limiter-divertor plasma-facing systems.

Description: The Advanced Limiter-divertor Plasma-facing Systems (ALPS) program was initiated in order to evaluate the potential for improved performance and lifetime for plasma-facing systems. The main goal of the program is to demonstrate the advantages of advanced limiter/divertor systems over conventional systems in terms of power density capability, component lifetime, and power conversion efficiency, while providing for safe operation and minimizing impurity concerns for the plasma. Most of the work to date has been applied to free surface liquids. A multi-disciplinary team from several institutions has been organized to address the key issues associated with these systems. The main performance goals for advanced limiters and diverters are a peak heat flux of >50 MW/m{sup 2},elimination of a lifetime limit for erosion, and the ability to extract useful heat at high power conversion efficiency ({approximately}40%). The evaluation of various options is being conducted through a combination of laboratory experiments, modeling of key processes, and conceptual design studies. The current emphasis for the work is on the effects of free surface liquids on plasma edge performance.
Date: September 15, 1999
Creator: Allain, J. P.; Bastasz, R.; Brooks, J. N.; Evans, T.; Hassanein, A.; Luckhardt, S. et al.
Partner: UNT Libraries Government Documents Department

Evaluation of Foamseal ceiling panels in the large scale climate simulator under winder conditions. Phase I

Description: This report serves to document Phase I of tests on ceiling panels fabricated by Foamseal Urethane Technology, Inc. in the Large Scale Climate Simulator (LSCS). The work reported here was accomplished during August, 1991.
Date: November 1, 1991
Creator: Wilkes, K.E. & Childs, P.W.
Partner: UNT Libraries Government Documents Department

Production of Hydrogen by Superadiabatic Decomposition of Hydrogen Sulfide - Final Technical Report for the Period June 1, 1999 - September 30, 2000

Description: The objective of this program is to develop an economical process for hydrogen production, with no additional carbon dioxide emission, through the thermal decomposition of hydrogen sulfide (H{sub 2}S) in H{sub 2}S-rich waste streams to high-purity hydrogen and elemental sulfur. The novel feature of the process being developed is the superadiabatic combustion (SAC) of part of the H{sub 2}S in the waste stream to provide the thermal energy required for the decomposition reaction such that no additional energy is required. The program is divided into two phases. In Phase 1, detailed thermochemical and kinetic modeling of the SAC reactor with H{sub 2}S-rich fuel gas and air/enriched air feeds is undertaken to evaluate the effects of operating conditions on exit gas products and conversion efficiency, and to identify key process parameters. Preliminary modeling results are used as a basis to conduct a thorough evaluation of SAC process design options, including reactor configuration, operating conditions, and productivity-product separation schemes, with respect to potential product yields, thermal efficiency, capital and operating costs, and reliability, ultimately leading to the preparation of a design package and cost estimate for a bench-scale reactor testing system to be assembled and tested in Phase 2 of the program. A detailed parametric testing plan was also developed for process design optimization and model verification in Phase 2. During Phase 2 of this program, IGT, UIC, and industry advisors UOP and BP Amoco will validate the SAC concept through construction of the bench-scale unit and parametric testing. The computer model developed in Phase 1 will be updated with the experimental data and used in future scale-up efforts. The process design will be refined and the cost estimate updated. Market survey and assessment will continue so that a commercial demonstration project can be identified.
Date: October 1, 2000
Creator: Slimane, Rachid B.; Lau, Francis S. & Abbasian, Javad
Partner: UNT Libraries Government Documents Department


Description: Condensing economizers increase the thermal efficiency of boilers by recovering sensible and latent heat from exhaust gas. These economizers are currently being used commercially for this purpose in a wide range of applications. Performance is dependent upon application-specific factors affecting the utility of recovered heat. With the addition of a condensing economizer boiler efficiency improvements up to 10% are possible. Condensing economizers can also capture flue gas particulates. In this work, the potential use of condensing economizers for both efficiency improvement and control of particulate emissions from small, coal water slurry-fired boilers was evaluated. Analysis was done to predict heat transfer and particulate capture by mechanisms including: inertial impaction, interception, diffusion, thermophoretic forces, and condensation growth. Shell-and-tube geometries were considered with flue gas on the outside of Teflon-covered tubes. Experimental studies were done with both air- and water-cooled economizers refit to a small boiler. Two experimental arrangements were used including oil-firing with injection of flyash upstream of the economizer and direct coal water slurry firing. Firing rates ranged from 27 to 82 kW (92,000 to 280,000 Btu/hr). Inertial impaction was found to be the most important particulate capture mechanism and removal efficiencies to 95% were achieved. With the addition of water sprays directly on the first row of tubes, removal efficiencies increased to 98%. Use of these sprays adversely affects heat recovery. Primary benefits of the sprays are seen to be the addition of small impaction sites and future design improvements are suggested in which such small impacts are permanently added to the highest velocity regions of the economizer. Predicted effects of these added impactors on particulate removal and pressure drop are presented.
Date: January 4, 1994
Creator: BUTCHER,T.A.
Partner: UNT Libraries Government Documents Department