Читать книгу Profit Maximization Techniques for Operating Chemical Plants - Sandip K. Lahiri - Страница 65

What are the major energy and product losses in a process? This is the first question that people should ask before embarking on a significant effort to improve profit. The answer to this question could lead to identification of major improvement opportunities and help to define the need for a large profit improvement effort. In a chemical process, a valuable product can be lost either with wastewater or vent to flare. In this step, a systematic approach is followed to calculate how much money gets lost in USD/h terms due to waste and vent. Not only product loss, but also energy loss, account for a major erosion of profit in many chemical plants. In a process, energy losses consist of both thermal and mechanical losses (Zhu, 2013). Thermal losses typically originate from column overhead condensers, product rundown coolers, furnace stack, steam leaks, poor insulation of heat exchangers/piping and vessels, and so on. Mechanical losses could also be significant, which usually occurs in rotating equipment, pressure letdown valves, control valves, pump spill back, heat exchangers, pipelines, and so on. Some of the wastewater, vent gas to flare, and thermal and mechanical losses are recoverable with a decent payback of investment, but many others do not. An energy and product loss audit seeks to identify key recoverable losses. The audit is relatively quick and is designed to determine improvement potential. If the energy loss audit identifies large energy or product losses, more detailed energy assessment efforts will be undertaken later if so required. After identifying all the product and energy losses in a chemical complex, small improvement projects can be initiated and implemented to stop or reduce these losses. In this way, by reducing the money drain from plants, profit can be increased. Many companies in the world have been able to increase their profit 1–5% by following this simple but effective step.