The Application Research Of Pinch Technology On Dyeing Industry’s Energy-saving Optimization

For process industries with complicated hot streams (releasing heat) and cold streams (requiring heat), heat exchange net works are really difficult to be optimized to minimize the corresponding energy consumption. The pinch point technology, known as the process integration, was proved to be the most efficient method to optimize the heat exchange net work of process industries. By finding the pinch point, the energy target can be achieved using the heat exchangers to recover heat between cold and hot streams in two separate systems, one for temperatures above pinch temperatures and one for temperatures below pinch temperatures. In practice, the pinch point technology has been applied widely in petrochemical and chemical industries, reducing the operating energy consumption by an average of 10～50%. But the pinch point technology has not been used in dyeing industries.Energy integration of dyeing industry was carried out using Pinch technology. The pinch point temperature was analyzed to optimize the heat exchange net work of dyeing industry. The energy targets for the pinch point temperature were computed respectively for hot and cold utilities. Finally the Pinch analysis was then used to modify the core process to improve heat integration of dyeing industry.In this paper, the heat exchange network of San Yuan textile plant was analyzed by using the Pinch technology. The process data was represented as a set of energy streams as a function of heat load against temperature. These data were combined for all the energy streams in the Plant to give composite curves, one for hot streams and one for cold streams. Then the corresponding pinch point was then obtained. The most appropriate set of heat exchange matches was then determined. Compared with the original system, the consumption of steam and water is significantly reduced.All the results of the investigation showed that, comparing to the original method of waste-heat recovery, the innovative application of the Pinch technology regarding how a dyeing plant be modified in order to minimize the energy consumption.