Nearly one third of commercial energy used in plants goes to process heating. More efficient use of process heat can result in substantial fuel savings and cost reductions. Completing a detailed analysis of heating needs can help identify the following four critical items to guide optimization:
- Useful heat needed for processing steps or process stages or by the product;
- Heat losses associated with the processes that are unavoidable and unrecoverable;
- Heat losses that can be controlled, reduced or avoided; and
- Heat losses that can be recovered economically.
Industrial process heating is classified in three categories — high-, medium- and low-temperature systems. Processes such as cracking of hydrocarbons and synthesis of ammonia require high-temperature heating, while fractionation of oils and most reaction vessels use medium-temperature heating. All drying, evaporation and sterilization processes require low-temperature heating. Cost reduction and optimization opportunities exist in all three categories