Staged Combustor Evaluation of Low Rank Coal Fuels

The combustion characteristics of fuels derived from low rank, coals have been evaluated at firing conditions representative of an industrial gas turbine engine. Data have been acquired for five fuels containing sub-bituminous coal and one using a lignite. The sub-bituminous fuels were coal-water mixtures differing in either the coal processing or coal loading. One slurry was based on minimally-processed coal which contained relatively high ash and internal moisture levels; the coal loading was limited to 42 pct to sustain acceptable handling. The other four slurries presented different loading of an improved-quality form of the same parent coal; slurry loadings up to 55 pct were achieved, providing nearly 50-pct greater heating value than the minimally-processed fuel. The lignite coal was also processed to produce an improved-quality slurry. Attempts to deliver and combust powdered, sub-bituminous coal were not successful. All tests were performed in a combustor configured to achieve geometrically separated zones of fuel-rich and fuel-lean combustion. Test results indicated a lower limit of fuel energy density as necessary to sustain stable combustion; efficiencies greater than 95 pct were only achieved for improved-quality fuels. The staged combustor approach again demonstrated its ability to control the conversion of fuel-bound nitrogen to NOx as concentrations down to 40 ppm (15 pct 02) were recorded.

Performance Testing of HTHP Electrostatic Precipitator at NYU PFBC Facility

NYU has an ongoing research program which is being funded by DOE to test three types of high-pressure, high-temperature filters. The main objectives of the testing program are: (1) to establish the performance capability of the filters under high-pressure and high-temperature conditions; and (2) to evaluate the dust collection efficiency. Shakedown tests for a duration of about 50 hours was completed during October 1986. Testing of the electrostatic precipitator (ESP) is in progress. The first test with ESP was performed during the middle of November 1986. The operating experience with respect to the test facility, and in particular with the particulate sampling systems, is reported in this paper. Additionally, some test results are also discussed.

U.S. Department of Energy Coal-Fueled Gas Turbine Program: A Status Report

Beginning in 1982, the Department of Energy (DOE), through the Morgantown Energy Technology Center (METC), has been conducting research for the purpose of verifying the feasibility of using coal fuels in heat engine applications. The heat engines of primary concern are the gas turbine and the diesel engine. The overall program objective is to develop the technology base for an environmentally sound, integrated heat engine system which will produce cost-competitive energy from coal. This paper will present the status of the gas turbine portion of this program.

Coal-Fueled Gas Turbine Combustor Island Development

Solar Turbines Incorporated, a subsidiary of Caterpillar Inc., is currently developing under DOE sponsorship a coal-fueled version of its industrial Centaur Model H gas turbine for cogeneration applications. A critical sub-system component is the coal-fueled combustor island consisting of a Two-Stage Slagging Combustor (TSSC) with an integrated Particulate Rejection Impact Separator (PRIS). Earlier development of the TSSC consisted of basic feasibility demonstrations and emissions evaluations and has been reported previously together with preliminary system design and assessment data. This paper reports on the continued bench-scale development of the combustor island with the objective of developing a data base suitable for use in scaling-up the design by an order of magnitude to a rating consistent with application to the 3.8 MW Centaur Model H gas turbine. Development activities have included analytical and flow visualization modeling; sorbent injection tests for control of sulfur oxides; and baseline evaluations of a continuous slag removal system. A preliminary engine-size combustor island design is also presented.

Correlation Between Sodium Sulfate Mass Transfer and Low-Temperature Hot Corrosion

A mass transfer model is developed that considers diffusive and chemical aspects of sodium sulfate formation and deposition on cooled blades of coal-fired gas turbines. The roles of gas phase condensation of sodium sulfate and multicomponent diffusion across a chemically frozen thin boundary layer are elaborated. A rational procedure is presented for correlating material wastage with laboratory weight gain data obtained by exposing alloy specimens pre-coated with a thin film of salt to SO2-SO3 in an oxygen environment. The sodium sulfate mass transfer model is used in conjunction with the correlation to project blade corrosion and lifetime as a function of gas turbine inlet temperature, blade cooling, and sodium and sulfur contaminant concentration.

The Design of a 3MW Kalina Cycle Experimental Plant

An experimental project is now underway to demonstrate the advantages of the Kalina cycle technology. A Kalina Cycle Experimental Plant (KCEP) will be built as a 3 MW bottoming cycle using the waste heat from a facility within the Energy Technology Engineering Center (ETEC), a U.S. Department of Energy laboratory located in Canoga Park, California. The design of the experimental plant is presented, including the process flow diagram, heat and mass balance, and specifications for the plant’s major equipment; the waste heat boiler, turbine generator and distillation/condensation subsystem. Using a mixture of ammonia and water at a mass ratio of 70/30, and a new condenser design based on absorption principles, the Kalina cycle plant will attempt to demonstrate its superiority over the Rankine steam cycle. Based on single pressure designs at comparable peak cycle temperatures, the Kalina cycle’s output should exceed that of the steam cycle by 25 percent.

The Performance of a Surrogate Blend in Simulating the Sooting Behavior of a Practical, Distillate JP-4

A surrogate fuel has been developed to simulate the atomization and combustion performance of a practical, petroleum distillate JP-4. The surrogate is comprised of fourteen pure hydrocarbons and formulated to reproduce the distillation curve and compound class composition of the parent petroleum distillate fuel. In previous work, the atomization performance (evaluated in terms of the atomization quality in an isothermal chamber), and the combustion performance (evaluated in terms of the mean axial velocity and thermal fields in a spray-atomized, swirl-stabilized, model laboratory combustor) were found to be equivalent for the petroleum and surrogate JP-4. The present study addresses the sooting performance of the two fuels, as well as that of two reference fuels (isooctane and a high aromatic petroleum JP-5) of purposefully disparate properties. The sooting performance of the petroleum and surrogate JP-4 are nearly identical, and distinctly different from that of either the isooctane or the JP-5. The surrogate represents, as a result, an attractive fuel blend for the study of fuel compositional effects on the combustion performance of practical fuels in a spray-fired combustor.

Efficiency Enhancement of a Pipeline Turbocompressor With a Gas/Steam Combined Cycle

The problems typically encountered with the basic engineering of a combined-cycle installation are examined here in general; the selection criteria of the operating fluid and determination of the thermodynamic parameters of the steam cycle are also dealt with in the appendix. The combined-cycle gas compression unit at present under construction in SNAM’s Station at Messina is then described extensively; the system, designed to comply with the specific requirements of a gas compression plant (unmanned continuous operation in severe environmental conditions), is characterized by an efficiency higher than 47% at ISO conditions. Special attention is paid to the control system and to the analysis of the dynamic behaviour of the gas / steam unit by which two pipeline compressors (the main one driven by the gas turbine and the auxiliary one driven by the steam turbine) are made to run in parallel.

Increasing the Capacity Factors of Base Load Generating Facilities by Storage of Electrical Energy in Aquifers as Compressed Air

This paper sets out the advantages of using “off-the-shelf” equipment to produce an effective Compressed Air Energy System (CAES) and to develop the storage parameters of those geological entrapments that can be pressurized with air for the generation of electrical energy on demand. The long lead time and the developmental cost needed to perfect turbo-machinery for aquifer storage has been a deterrant on the utilities in their desire to implement air storage in aquifers. Off-the-shelf hardware and predesigned turbo-machinery specified herein is readily adaptable to aquifer storage parameters and can be manufactured without the expense and uncertainty related to developmental hardware. Hence, normal equipment manufacturer’s assurances and guarantees are available for these applications. When compared to the alternative storage opportunities such as; pumped hydro, battery storage and superconducting magnetic storage, the cost of compressed air storage in aquifers is a fraction of the first cost of these alternatives and as good or better in operating costs.

High Operation Flexibility and Reliability by Multi-Unit Compressor Arrangement for Gas Storage Applications

The growing gas market and the increasing ratio of imported gas to gas produced within a country requires an expanded capacity for buffer gas storage to compensate for differences between constant import gas flow and seasonal variances in consumption. For economical operation of the gas storage facility and for moving extensive quantities of gas, high operating flexibility as well as high availability and reliability of gas compression equipment are required. This paper will report on an underground gas storage project and indicate specific objectives for the project in reservoir engineering, gas compression and free-flow withdrawal duties. It will also deal with the sizing and selection of gas turbine driven centrifugal compressor sets, including the required station equipment. Finally, operating experience will be discussed.