MINIMIZATION OF WASTE WATER USING PINCH TECHNOLOGY IN INDUSTRY

Abstract

Water is an important element for many industrial operations. The rapid growth in population, industrialization and urbanization has increased the demand for water, casting adverse effect on environment. The scarcity and high price of water along with stricter regulations on discharge of industrial effluents have emerged as important factors in commodity material manufacturing. With the rise in the cost of water .supply and treatment, there will be elevated pressure on the industries to reduce water consumption. Many types of methodologies are available to save fresh water and thus, decrease waste water generation. Out of these, Water Pinch is one of the most important technologies for waste water minimization. Basically, it is a methodical accounting procedure based entirely on mass conservation. This technology treats the water utilization process of an industry as an organic whole, and considers how to allocate the water quantity and quality to each water using units so that water reuse is maximized within the system and as a result -the waste water generation is minimized simultaneously. In this dissertation, sincere efforts have been put to demonstrate the potential of Water Pinch Technology by taking up real world problems of industries. Two different case studies are discussed in details. All case studies have been considered as retrofitting problems and have been solved meticulously considering existing piping and plant layouts. The cost benefit analysis of the above case studies have also been included. Based on availability of plant data two case studies namely (1) Pragati Power Plant, New Delhi (2) Starch Industry, Ahmedabad, Gujarat have been taken up. Different cases of the above two industries have been solved which are based on conventional water pinch problems. After the analysis of Pragati power station water using network a modified network has been proposed which can save Rs. 7, 09, 317/- as operating cost per year. The Pragati power plant, New Delhi have started experimentation for implementation of the above strategy. The thermal pinch analysis shows that if modified PFD is adopted then the same amount of cooling in the industy can be carried out with the use of far less heat transfer area. The reported area savings are of the tune of 50.7% iv The analysis of water using network of Starch Industry was done using water pinch technology and a modified PFD of water using network was proposed which could save Rs. 8, 44, 923/- as operating cost per year. In view of the prepage, it can be concluded that Water Pinch Technology puts minimal pressure on natural resources and helps to maintain ecological balance and thus conserves the water qualities of rivers, lakes, surface water an