Study On The Industry Water-supply System Based On The Minimum Freshwater Flowrate

Industrial enterprise is the largest water-user for its considerable consumption. Its water-saving performance has direct influence on the community's water-saving work. However, industrial enterprise has a wide range. Different industrial enterprise's requirement on water quantity and water quality varies markedly, and even within the same industrial enterprise, different water-using unit has varied requirements on water quantity and quality. Thus, calculating method for industrial enterprise water-supply system is at all times a concentration of water-supply research. The method must be in response to industrial enterprise water quantity and water quality requirements. This paper proposes a method of industrial water-supply system water quantity calculation whenDuring the research of industrial water supply system, we must clear the classification of industrial water and various water definitions first .As the current standards and literatures have different descriptions on the same water which will cause inconvenience, so this paper unified the classification of industrial water and definitions for various water by referring various nation-level standards. Water brought in by raw material has not been presented in the above standard, but it affects the water quantity calculation. This paper first proposes that water brought by raw material should be regarded as input water and be taken into water balance, and same amount of water should be deducted during the calculation.Water-pinch point technique is the application of pinch point technique in water supply system. During the process of analyzing water-pinch point, first we should draw limiting concentration-composite curve according to the limiting water using statistics for each unit, and then determine the best water-supply line and water-pinch point as well as the smallest amount of fresh water according to the pinch point concentration and mass load. As for single foreign substance water-supply system, first calculate the minimum fresh water using water-pinch point method, and then distribute water-supply system using grid diagram method. As for mass foreign substance water- supply system, the above method is not available to the design of water-supply system directly. However, we can manage the path of wastewater reuse according to the corresponding rules and delete the path which can't be reused. For the water-using unit which has water loss, making it into two virtual units during the analysis of water-pinch point: Set the flow of unit I as same as the wastewater flow of original unit, limit import and export concentration are as same as the original one, too; Unit II is equal to the flow of water loss of water, limit export concentration equals to the original unit, and export concentration is set to limit the export of all units of water the maximum concentration. Connecting the side lines of limiting water profile with the origin of coordinates, take the smallest slope of a straight line as the optimal water supply line, and the "approximation" approach obtained the same results, but better and simpler in operation.According to concentration-composite curve drafted from the example's water-using process, this paper affirms the most appropriate water-supply point and water-pinch point, and then uses grid diagram approach to calculate each unit's water-supply quantity when this factory area's water-supply quantity is at the lowest level. Therefore, calculation of single foreign substance industrial enterprise water-supply system's water quantity design is made available when the fresh water quantity is at the smallest level.This research proves that water-pinch point technique can be applied in the design of single foreign water-consuming industrial enterprises. This calculating method decrease the industrial enterprise's fresh water supply, making water recycling more effective, which fairly resolves the industrial enterprise's water-saving problem in its design course.