Energy conservation heat recovery

Heve the energy consuming, heat recovery, and other energy conservation facilities been economically optimized for energy cost appropriate for the years in which the system will be operational ... 

An important by-product of most energy technologies is heat. Few energy conversion processes are carried out without heat being rejected at some point in the process stream. Historically, it has been more convenient as weU as less cosdy to reject waste heat to the environment rather than to attempt significant recovery. The low temperatures of waste heat in relation to process requirements often make reuse impractical and disposal the only attractive alternative (see Process energy conservation). 

The first step is energy conservation, which is the subject of Chapter 34. Recovery of rejected or wasted heat requires a careful analysis of the heat flow within the systems under survey Points to examine are ... 

Resource Conservation and Recovery Act Unsaturated Soil Water and Heat Flow United States Department of Agriculture United States Department of Energy United States Environmental Protection Agency... 

Heat recovery (or reuse) is an important and fundamental method of energy conservation. The main limitations of this method are ... 

Heat exchangers are a prime means of conserving energy in process plants by exchanging heat between process streams that need to be cooled and those that need to be heated. Much attention is directed toward optimization of heat conservation and recovery by selecting the proper heat exchanger network. 

Current Economics of Energy Conservation. Gyftopoulos and Widmer presented thirteen examples of the cost effectiveness of energy conservation measures (42-44) including an analysis of heat recovery in cement production. 

Purcupile, J. C. and Stas, J. D.,"Energy Conservation in Coal Conversion and Energy Conservation Potential in Heat Recovery Techniques A Case Study," In reference 16,... 

Heat pipes are particularly useful in energy-conservation equipment. One example is shown in Fig. 12-22 where hot exhaust gases are used to drive a waste heat recovery boiler. The hot gases from a combustion process, which... 

The distillation train first separates the benzene/toluene byproduct from main crude styrene stream (8). Unconverted EB is separated from styrene (9) and recycled to the reaction section. Various heat recovery schemes are used to conserve energy from the EB/SM column system. In the final purification step (10), trace C9 components and heavies are separated from the finished SM. To minimize polymerization in distillation equipment, a dinitrophenolic type inhibitor is co-fed with the crude feed from the reaction section. Typical SM purity ranges between 99.90% and 99.95%. 

This system also demonstrates the latest technologies in heat recovery by heat exchange of the hot oil in the drop tank with the incoming cold oil and by steam generation for reactor cooling. The hydrogenation department becomes a net exporter of steam, the ultimate form of energy conservation. 

The major conclusion is that the mass burning of unprepared municipal solid waste in heat recovery boilers is well established, and can be a technically reliable, environmentally acceptable and economic solution to the problem of disposal of solid wastes. It is not as cheap as is currently available land-filling. However, when the cost is considered of upgrading current landfills and establishing new landfills in accordance with the expected Resource Conservation and Recovery Act (RCRA) provisions, these mass burning waste-to-energy systems are expected to compare more economically with true sanitary landfills. ... 

The lower capital cost figures for various conservation measures (relative to the investment needed for new energy supplies) provide only a rough indication that such measures will yield attractive economic returns to the investor. Detailed payback calculations, similar to those discussed later for waste heat recovery equipment, are needed to establish economic feasibility in each specific case. 

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