Shanghai City Zhangjiang High-Tech Park New Energy Technology Co., Ltd. is referred to as "Zhangjiang Energy Supply". It was established in January 1994. It is a state-owned enterprise affiliated to Shanghai Shenneng Energy Services Co., Ltd., mainly providing centralized energy supply services to enterprises stationed in Zhangjiang High-Tech Park.

 The Zhangjiang Energy Supply and Waste Heat Reutilization Technology is to transform the layout and pipeline structure of the boiler sewage pipe of the company's heat source station. The sewage pipe flows through the bottom of the boiler soft water inlet tank in the form of a coil, and realizes the boiler drainage through heat exchange. Rapid cooling of sewage meets the standards, and use this reduced heat energy to preheat the soft water to achieve cost reduction, efficiency improvement, energy conservation and carbon reduction.

 At present, Shanghai's discharge requirements for industrial sewage include temperature requirements, requiring the temperature of corporate discharge water to be less than 60℃. The boiler sewage from the Zhangjiang Energy Supply Heat Source Station passes through the pressure relief meteorological separation of the continuous discharge expander and flows into the cooling pool. Since the cooling pool is limited by the site and cannot provide effective cooling conditions, it requires neutralization with tap water at normal temperature to make the boiler sewage meet the discharge requirements. Because the temperature of sewage water is too high, discharge after treatment not only wastes production water, but also the abandonment of high-temperature water is a great waste for boilers that require heat energy. Therefore, the company renovated the sewage pipe, passing the sewage pipe through the soft water tank coil, exchanging heat when passing through the water tank, and then entering the boiler sewage cooling pool.

 Before the technical transformation, the boiler sewage pipe of our company was made of DN50 304 stainless steel with a length of 11.4 meters. Since the water inlet and water outlet are at the same level, the continuous drainage sewage cannot fill the entire pipe when discharged through the water tank, resulting in the heat exchange area utilization rate is less than one-third. In addition, due to the uneven distribution of the coils, the heat cannot be fully utilized; after the technological transformation, a 24-meter-long DN50 and 304 stainless steel coil was added, and the water outlet of the heating coil was raised at the same time, so that when boiler sewage flows through the coil, it can fill the entire pipeline, increase the effective area for heat exchange, extend the residence time of the sewage in the coil, and make full use of the heat of the boiler sewage.

 The Zhangjiang energy supply and sewage coil renovation project combines theory and practice and has the following three technical advantages:<o></o>

 1) Make full use of the temperature difference of the boiler water system: the tap water inlet temperature (maximum 30℃) is lower than the boiler's continuous discharge sewage (the temperature at the continuous discharge outlet is 93℃). Conditions are allowed for cold and heat exchange, and the temperature of the continuous discharge water can be exchanged., there is a temperature difference that releases heat.<o></o>

 2) Drainage gradient design: Due to the pressure of drainage sewage discharge, the discharge will not be affected after the outlet level of the heating coil increases and can be discharged;<o></o>

 3) Save equipment investment, short payback period, and technical and economic feasibility. Increasing the length of the heating coil can achieve significant economic benefits and solve the problem of high temperature in sewage.