Energy recovery waste-heat boilers

Fig. 1. Effect of energy use on total cost where total cost is the sum of capital and energy costs for the lifetime of the plant, discounted to present value. Point D corresponds to the design point if the designer uses an energy price that is low by a factor of four in projected energy price. Effects on costs of (a) pressure drop in piping, (b) pressure drop in exchangers, (c) heat loss through insulation, (d) reflux use, and (e) energy recovery through waste-heat boiler...

Figure 3.12. Reformed gas waste-heat boiler arrangement of vertical U-tube water-tube boiler (Reprinted by permission of the Council of the Institution of Mechanical Engineers from the Proceedings of the Conference on Energy Recovery in the Process Industries, London, 1975.)...

Recovery of a portion of the heat energy available in the hot (>2000°F) syngas stream of the 25 TPD unit is intended to improve the net thermal efficiency of the process by installing a waste heat boiler, which will produce steam for use in process heating. In a larger gasification system, additional energy recovery equipment could be installed to further improve efficiency. However, the capital costs of such equipment are not justified for a small 25 TPD pilot unit. 

Waste-heat and other special-purpose boilers Special designs provide boilers for waste heat and chemical recovery, waste-to-energy, and combined-cycle installations, pulverized-bed, and even biomass applications. 

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