Integration of a Process Waste Gas into a Site's Energy Concept

Abstract

In 1996, the BASF Corporation's Geismar, Louisiana site determined that the increased steam demands of their aggressive investment program would require them to expand their steam generation capacity. The site had operated a gas turbine based cogeneration system since 1985 so they naturally reviewed the economics of another such installation. At the same time, a new Acetylene plant was being planned, which generated a large process waste gas stream. Conceptual studies indicated that integrating the two projects would provide significant economic advantages. The new gas turbine is similar to the first unit with a capacity of approximately 37.5 MW. However, there are several factors that make this a unique installation. For one, the new unit has a unique dual fuel capability -natural gas as well as the process waste gas. The waste gas is hydrogen and carbon monoxide rich, and has a much lower heating value per cubic foot than does natural gas. The use of waste gas is a great advantage since it avoids flaring this valuable "fuel" with the associated increased emissions. The innovative fuel system was designed to accommodate a wide range of gas mixes to maximize the amount of waste gas that can be utilized in the unit. The unit is equipped with a state of the art Selective Catalytic Reduction system in the exhaust stack to greatly reduce the amount of NOx emissions produced by the installation. The emissions are a maximum of 8-PPM NOx with natural gas and 25 PPM with 100% waste gas.