ECONOMIC ADVANTAGES OF WASTE HEAT RECOVERY BOILERS OVER COMBUSTION BOILERS IN PLANTS WITH HIGH EXHAUST HEAT

In a sponge iron plant, the exit gases from rotary kiln (pyro processing device) has a peak average temperature of 850°C to 950°C. Although it is possible to convert these waste heat into usable power, such potentials are not fully realized because most of the industries, particularly in Asia, continue to operate with older systems. The appreciable volumes of heat released are cooled by cooling systems before the flue gases are released into the environment. These cooling systems requires power to operate in addition to the power requirements of the plant, which are produced by combustion boilers. However, waste heat recovery boilers (WHRB) converts such heat into functional energy by eliminating the cooling systems. In addition to that, the installation and operation costs of WHRB are lower than combustion boilers. WHRB not only produces operable power but also reduces the emission of pollutants since waste heat acts as the fuel source instead of external fuel source. Therefore, the importance of such conversion techniques are emphasized in terms of economic analysis to reduce the use of conventional energy sources and use the available resources to its maximum potential