In brief: The Anderson knee stabler restricts the valgus stress to the knee joint, which should decrease the number and severity of collateral ligament injuries and reduce the number of meniscal injuries. The authors reviewed medical records of football players at the University of Southern California (USC) and recorded the number and type of knee surgeries from 1980 to 1984, noting which players wore braces and which did not. Results showed that the Anderson knee stabler is beneficial in preventing collateral ligament and meniscus injuries to the knee. There have been no grade-3 injuries to the collateral ligaments caused by direct contact to the brace. The authors recommend that all USC linebackers and interior linemen wear the Anderson knee stabler during practices and games but say that further longitudinal data are needed.

A program has been underway since 1986 by Westinghouse Electric Corporation, Textron, Inc., and the sponsoring agency, the Morgantown Energy Technology Center (METC) of the U.S. Department of Energy (DOE), as participants, to establish the technology base for coal-fired combustion turbines targeted for power generation (50 to 150 MW size units). The developed system must be able to burn unbeneficiated, low-cost, utility-grade coal and meet the EPA New Source Performance Standards (NSPS) for coal-fired steam generators (Thoman et al., 1987). Development of a high pressure (12 to 16 atms) slagging combustor is the key to making a direct coal-fired combustion turbine a commercial reality. In testing to date, a 6 atm slagging combustor, rated at 12 MMBtu/hr (12.7 MHkJ/hr) has demonstrated its ability to handle high- and low-sulfur bituminous coals, and low-sulfur subbituminous coal. The program objectives relative to combustion efficiency, combustor exit temperature and pattern factor, NOx emissions, carbon burnout, and slag rejection have been met. Today, Northern States Power, working with Westinghouse with assistance from Textron is developing a plan to commercialize a direct coal-fired advanced combined cycle (DCFACC). Included in this plan is a pilot plant (which does not include a combustion turbine) and a demonstration plant that would utilize a 50 MW combustion turbine. The first commercial DCFACC, which would Include a 100 MW combustion turbine, is scheduled to be operational by the year 2001. The cooperative effort among Northern States Power, Westinghouse, and Textron is financially independent of the work now sponsored by DOE/METC. This paper presents the status of the pressurized slagging combustor development program including recent work to reduce alkali, particulates and SOx levels leaving the combustor and gives an overview of our commercialization process and plan.

The objective of this effort is to establish the technology required for private sector use of an advanced coal-fueled gas turbine power system. The system is to burn low-cost, utility-grade coal, and yet comfortably meet the EPA New Source Performance Standard (NSPS) for coal-fired steam generators. Plant thermal efficiency is to surpass competing coal-utilization cycles. Development of a successful high pressure slagging combustor is the key to meeting these objectives. As subcontractor to Westinghouse, Avco Research Laboratory/Textron (ARL) has designed and fabricated a subscale slagging combustor based on earlier MHD and boiler-type units. The new device is currently in a 12½-month developmental series of tests. Based on these series of tests, Westinghouse is to design, manufacture, and test a full-scale slagging combustor in a test cell at nominal field operating conditions. The activities described in this paper are sponsored by the Morgantown Energy Technology Center of the Department of Energy.

An innovative cleanup concept, based on a Confined Vortex Scrubber (CVS), for fine particulate removal from combustion flue gases has been developed, tested and verified. The CVS consists of a cylindrical vortex chamber with multiple tangential flue gas inlets. The clean gas exit is via two central tubes. Water is introduced into the chamber and is confined within the vortex chamber by the extremely high centrifugal forces generated by the gas flow. The confined water forms a layer through which the flue gas is forced to bubble. Due to the high radial acceleration, the bubbles generated are very small, leading to a strong gadliquid interaction, high inertial separation forces and extremely efficient fine particle cleanup. Collection efficiencies in excess of 99.5 percent have been measured f o r extremely fine fly ash (mean particle size 3 microns). A collection efficiency of 98percent has been measured for 0.3 micron diameter particles.

Under sponsorship of the Morgantown Energy Technology Center of the Department of Energy, the Westinghouse Electric Corporation and Avco Research Laboratory/Textron (ARL) are developing a direct coal-fired 80-MW combustion turbine. This is to be an element in a 207-MW direct coal-fired combustion turbine combined cycle, comprising another combustion turbine, a heat-recovery steam generator, and a steam turbine. Following conceptual and economic studies, the first experimental task has been to develop a direct coal-fired slagging combustor in small scale. A year’s testing with this unit has now been accomplished. It is thus possible to discuss experimental results in the areas of slag management, general combustor operability, coal fuel feed, heat loss, pressure loss, combustion efficiency, and emissions. Westinghouse and ARL selected the slagging combustor for use in this program because of its unique ability to accept inexpensive standard utility-type coal without sending excessive pollutants and particulates to the expander-turbine. It accomplishes this by burning the coal at a temperature high enough to melt the ash, and then removing the molten slag with an impact separator. This combustor is also of the rich-lean type, which allows it to emit very low levels of NOx. Sulfur oxides are controlled through injection of a sorbent which combines with gaseous forms of sulfur in the rich zone, and then takes them out with the slag. The plan in this program is to develop the slagging combustor in small scale at 12 million Btu/h (12.66 million kJ/h) heat input, 6 atmospheres pressure, and then move to design and verification testing of a full-scale 70 million Btu/h (73.85 million kJ/h), 14-atmosphere unit. It is with the smaller burner that this paper is concerned. During this period, coals have been fed into the 6-atm combustor exclusively in the dry-pulverized form with air as the carrier gas. To date, high- and low-sulfur eastern bituminous, and low-sulfur western subbituminous coals have been evaluated, with, and without sorbents, which have included various calcium and iron containing minerals. Coal samples have been of the 200 mesh size, and have not been beneficiated. Combustor operation has been efficient and repeatable and slag flow has been symmetrical and manageable. Slag removal has been greater than 90 percent and carbon burnout has been greater than 99 percent. Nitrogen oxide emissions meet the goals of EPA’s NSPS for coal-fired plants. Current tests are focused on the goal of 90 percent sulfur removal. Although some results are available, various sorbents and injection techniques continue under test.