Fuels for Heat Engines From Mild Gasification of Coal

The amount of oil imported into the United States in the last few years has increased sharply, and has again reached the point where the U.S. may be faced with an oil embargo by foreign oil suppliers. A large part of this oil is used in heat engines, for transportation and for the production of power during periods of peak demand.

Performance of Hot Gas Clean-Up Devices Tested at the NYU DOE-PFBC Facility

Three hot gas clean up units namely, the Screenless Granular Bed Filter (GBF), Ceramic Cross-flow Filter (CXF) and High Temperature, High Pressure Electrostatic Precipitator (ESP) designed for PFBC combined cycle power applications were tested at the New York University (NYU) DOE-PFBC facility located at Westbury, New York using a 780 mm ID pressurized fluidized bed combustor. The combustor was operated up to 10 atma and 870 °C. With the exception of the ESP whose performance was hampered by persistent electrode bushing failure, the particulate capturing efficiencies of the GBF and the CXF were predominantly in the upper 90 % range. The dust loading leaving the filters was consistently lower than the NSPS particulate emission limit. The results also indicate that the filter exit gas stream may meet the gas turbine particulate tolerance limit. None of the three high temperature, high pressure (HTHP) gas clean up units tested emerges as a favorite for use in cleaning PFBC exhaust stream because, each has mechanical design as well as operational flaws which could be corrected. The Cross-flow filter suffered from filter element cracking or delamination or gasket failure during its short test program. The backpulse cleaning system also needs to be optimized. The GBF is susceptible to media bubbling and granule flow problems through its lower seal leg. The Electrostatic Precipitator tested at NYU failed because its electrode bushings cracked due to overheating and could not hold their designed voltage. Further HTHP filter testing at the sub-pilot plant scale is necessary to optimize filter design and develop effective operational procedures for the hot gas clean up systems that will make them viable for commercial PFBC application.

An Integrated Steam/Gas Turbine-Generator for Combined-Cycle Applications

Combined-cycle power plants have been built with the gas turbine, steam turbine, and generator connected end-to-end to form a machine having a single shaft. To date, these plants have utilized a nonreheat steam cycle and a single-casing steam turbine of conventional design, connected to the collector end of the generator through a flexible shaft coupling. A new design has been developed for application of an advanced gas turbine of higher rating and higher firing temperature and exhaust gas temperature with a reheat steam cycle. The gas turbine and steam turbine are fully integrated mechanically, with solid shaft couplings and a common thrust bearing. This paper describes the new machine, with emphasis on the steam turbine section where the elimination of the flexible coupling created a number of unusual design requirements. Significant benefits in reduced cost and reduced complexity of design, operation, and maintenance are achieved as a result of the integration of the machine and its control and auxiliary systems.

Digital Controls Retrofit of a 290MW Combined Cycle Power Generation Plant

Public Service Company of Oklahoma (PSO) operates a combined cycle, Westinghouse PACE generating station which was commissioned in 1972. The plant consists of two Westinghouse 501B6 gas turbines, two heat recovery steam generation units with afterburners, and a single 120MW steam turbine generator. PSO made the decision to upgrade the complete plant control with a state-of-the-art triple modular redundant control system, designed to provide entire control of the generating station. The paper describes the overall retrofit project, from project conception and justification through installation, commissioning and operating results.

Advanced Particle Control for Coal-Based Power Generation Systems

The Morgantown Energy Technology Center (METC) of the U.S. Department of Energy (DOE) is actively sponsoring research to develop coal-based power generation systems that use coal more efficiently and economically and with lower emissions than conventional pulverized-coal power plants. Some of the more promising of the advanced coal-based power generation systems are shown in Figure 1: pressurized fluidized-bed combustion combined-cycle (PFBC), integrated gasification combined-cycle (IGCC), and direct coal-fueled turbine (DCFT). These systems rely on gas turbines to produce all or a portion of the electrical power generation. An essential feature of each of these systems is the control of particles at high-temperature and high-pressure (HTHP) conditions. Particle control is needed in all advanced power generation systems to meet environmental regulations and to protect the gas turbine and other major system components. Particles can play a significant role in damaging the gas turbine by erosion, deposition, and corrosion. Erosion is caused by the high-speed impaction of particles on the turbine blades. Particle deposition on the turbine blades can impede gas flow and block cooling air. Particle deposition also contributes to corrosive attack when alkali metal compounds adsorbed on the particles react with the gas turbine blades. Incorporation of HTHP particle control technologies into the advanced power generation systems can reduce gas turbine maintenance requirements, increase plant efficiency, reduce plant capital cost, lower the cost of electricity, reduce wastewater treatment requirements, and eliminate the need for post-turbine particle control to meet New Source Performance Standards (NSPS) for particle emissions.

Direct Coal Firing for Large Combustion Turbines: What Do Economic Projections and Subscale Combustor Tests Show?

Westinghouse Electric Corporation and Avco Research Lab/TEXTRON have been working for three years on a Department of Energy program to establish the technology required for commercially viable direct coal-fueled utility-size gas turbine combined cycles. These plants are to meet the EPA’s New Source Performance Standards for coal-fired steam generators and to generate power at a favorable cost-of-electricity relative to steam plants with flue gas desulfurization. Economic projections indicate that the latter goal is achievable by a method of approach which uses inexpensive utility-grade coal, and removes the resulting sulfur and ash through use of a slagging combustor in the gas turbine cycle. High pressure, subscale slagging combustor tests have been underway for several months at Avco Research Laboratory and are encouraging. Experimental highlights are shown here.

The First 200 MWGAS Turbine Ordered in the World

The French generation mix is characterized by a great number of nuclear power plants.