Weighing in the environmental Factor
Thermal pollution and process-waste disposal restrictions have forced engineers to replace, reroute, retrofit-and, in some cases, reconsider the need for-a waste-heat recovery system. The following technology overview stresses products that can meet the maintenance demands imposed by these new restrictions.
DECISIONS ABOUT WASTE-heat recovery used to be based on simple economic considerations: Can you use the waste heat? Will the cost of recovering it be outweighed by the energy you will save? Can you afford the ROI you've calculated? Today, decisions about waste-heat recovery are being influenced and complicated by a variety of environmental factors.
Growing awareness of pollution problems and restrictive environmental regulations pose new design and operation challenges for the modern process industrial plant (chemical, pulp and paper, pharmaceutical, food). Depending on the plant's location, heat recovery using waste or process streams may be economically and environmentally efficient. In other instances, however, where waste streams must be treated or sent for disposal, heat-recovery devices must be used to cool the stream. Sometimes, effluent streams that flow into ponds or lakes meet all environmental standards except temperature; these streams must be cooled down to minimize the effect of thermal pollution on the environment.