Opportunities for heat exchanger applications in environmental systems

There is a worldwide interest in using pollution prevention methods to eliminate or lessen air, water, land and thermal pollution problems. Pollution prevention is designing processes that do not create pollution in the first place. Heat exchangers play an essential role in pollution prevention and in the reduction of environmental impact of industrial processes, by reducing energy consumption or recovering energy from processes in which they are used. They are used: (1) in pollution prevention or control systems that decrease volatile organic compounds (VOCs) and other air pollutant emissions; (2) in systems that decrease pollutants in wastewater discharges, the amount of the discharge and thermal pollution; and (3) used to recover energy in facilities that incinerate municipal solid waste and selected industrial hazardous wastes. Heat exchangers are also used in the heating, cooling and concentration of process streams that are part of many other pollution prevention or control related processes. In this paper, first presented is background information on the role of heat exchangers, their types, and a discussion of environment pollution problems. Next, the role of heat exchangers is outlined in the prevention and mitigation of the following pollution problems: air pollution from VOCs, sulphur oxides (SOx), nitrogen oxides (NOx); water pollution from industrial processes, thermal pollution, and land pollution resulting from municipal solid wastes or industrial hazardous wastes. Specific Research and Development needs for environmental heat exchangers are then summarized in the paper. It is hoped that this paper will challenge the heat transfer engineering community to further enhance the role of heat exchangers for pollution prevention and global sustainable development.