过程设计与合成.doc

The optimal design of the heat integration Abstract The optimal design of the heat integration is about the heat transfer and energy conservation fields. In this article, we discuss the optimal design by applying the Grid diagram method. Reducing the utility steam consumption below the original design (6.12MW) is the ultimate goal of the design. In order to minimize the utilities and operation cost, we had tried kinds of designs to save the steams and cooling water, the result shows us that ideal consumption could not be realized, however, our design could reduce the original design value to 3.36MW. Keywords: Heat process; Grid diagram; Utility consumption; Optimal design Introduction The process of this design is to cool the product streams and heat the cold feed streams, the design applied the heat recovery to save more energy. In the original design, the utility consumption: steam, 6.12MW; cooling water, 3.6MW. However, the improved design reduce the steam consumption to 3.36MW, in addition, the cooling water has decreased to 0.84MW. Thus, the improved design could save more energy and decline the cost of the operation. Design The original flow sheet is showed by the Fig. 1; the duty of the process is to cool the two product streams and heat the two cold feed streams. Fig. 1. The flow sheet of the original design. In that process, the cold Feed 1 is heated from 30℃ to 120℃; Feed 2 is heated form 60℃ to 100℃. Meanwhile, the Product 1 is cooled from 180℃ to 80℃; Product 2 is cooled form 130℃ to 40℃. In order to show that process more carefully, the Table 1 give more specific data of that process. Table 1. The heat exchange information of the streams The schematic diagram of the original design is obtained in Fig. 2, which tells us the basic information, and the Fig. 3 is the improved design, which could save more utility consumptions. Fig. 2. The schematic diagram of original design. Fig. 3. The schematic diagram of improved design. After