Research Needs of the Power Industry

Abstract

The Clean Air Act of 1990 has changed the way utilities burn coal. Utilities are now studying scrubbers, low NOx burners, fuel switching and fuel blending just to name a few changes. The Clean Air Act Amendments have also changed the way utilities do business.Utilities are now looking to buy and sell emission credits, which may be tied to fuel purchases and fuel contracts. The purchasing or selling of credits may also be tied to interchange of electricity and they are being traded on the open market to other utilities and industries.

Most utilities have boilers that were designed to burn a specific fuel and, in most cases, the fuel was a high sulfur, high Btu, bituminous coal. With fuel switching many boilers are now being required to burn a fuel that is drastically different than that for which the boiler was designed. This is leading to a whole range of new problems. Fuel engineers now are more concerned with the slagging, fouling, corrosion and erosion that can take place in the boiler, and not only how the fuel burns.

Utilities now look not only at the Btu of the fuel but are concerned with the ash chemistry, grindability, and the ultimate analysis, especially nitrogen and oxygen that is inherent in the coal. Many utilities are not geared for and do not have the people and expertise necessary for all of the studies and evaluation that must be done. Some areas that need to be addressed by research are slagging and fouling indices for western coals and blends of eastern and western coals. Corrosion indices are needed which pertain not only to the high temperature superheater and reheat areas of the boiler, but also to the backpasses, the economizer, air heater, and especially the precipitator. The effects of chlorine in a boiler and hazardous air pollutants need to be addressed.

Fuel switching has also caused precipitator problems. Most precipitators are designed to handle a low resistivity, high sulfur coal ash. Most low sulfur coal produces a high resistivity ash which is very difficult to precipitate. Work needs to be done on identifying coals that are difficult to collect as well as those coals that will not accept flue gas conditioning, and why the ash won’t condition.

Conferences of this type are very important for the open exchange of information between researchers and industry. Many times the research that is done is very interesting. It produces a lot of answers academically but is of very little value to industry because it can not be related to a large industrial boiler consuming 3,00010,000 tons of coal per day. The open exchange of information between what industry needs and what research can provide is essential to provide everyone involved with direction. Industry needs answers today, academics need to pursue long term approaches but they also need to address the short term, what industry needs today to answer immediate questions.