Reuse of condensate water

Condensate is generally used through staged flash evaporation. The steam resulting from this process, if uncontaminated, can be fed into the steam network; low-pressure steam can go to the deaerator. The condensed liquid obtained after flash evaporation is usually cooled in a heat exchanger before being sent back to the water purification system for further purification and reuse

A small amount of condensed water can be directly recycled to the deaerator as boiler feedwater. For large quantities, it can be recovered through staged flash evaporation to produce steam of different grades for the factory, thereby improving utilization efficiency. Closed-loop recycling is generally used. What are the measures for reusing condensate water, and what equipment is available for this purpose? 1. Directly return to the deaerator ； 2. Use a flash tank for recovery ； 3. Refiner. 3. What is the current status of the application of advanced technologies such as heat pumps and heat pipes in China? As far as I know, this technology is not widely used in large enterprises at present. It is mainly based on investment costs and the consideration of utilizing low-grade heat sources. Large enterprises have many low-grade heat sources, but their utilization remains virtually non-existent at present.

What was said upstairs is great; however, when it comes to energy conservation and emission reduction, much of it remains just talk without any actual action. In my boss’s words, the potential is huge – 20% improvement is definitely achievable! Many advanced technologies and equipment have not been widely adopted quickly; at present, we are using lithium bromide

In our plant, both the ammonia synthesis and urea production units use steam turbines to drive the compressors. The resulting steam is then condensed through surface cooling using circulating cooling water. The condensed water is sent to various units, where it is further treated in deoxidizers before being fed into the corresponding steam drums to generate steam for reuse:handshake :handshake

1. Using closed-loop recovery for condensate can save a large amount of thermal energy and prevent energy waste; for units equipped with boilers, recovering it to the deaerator is the most ideal solution. 2. After the latent heat of vaporization has been utilized, the condensate can be directly used as a heating source in other heat exchange equipment. If the back pressure for vapor condensation is high enough, a flash tank can be installed to produce low-pressure steam for use in the production facilities. Steam and condensate water are utilized step by step according to the actual heat-consuming equipment in the plant. 3. Heat pump technology is used to recover waste heat generated during the production process, enabling the conversion of low-grade thermal energy into higher-grade thermal energy for utilization. However, its thermal conversion efficiency is relatively low; the efficiency of the latest second-generation absorption heat pumps generally does not exceed 55%. It is not advisable to use higher-grade condensed water in heat pumps, as it results in excessive waste. Heat pipe technology is an indirect heat exchange device with high efficiency; it has many advantages, but it cannot transfer the heat from a cold heat source to a hot heat source like a heat pump, and therefore it is not suitable for the recovery of heat from condensate water as mentioned by the poster. Taking all of the above into account, the method with the highest heat utilization efficiency is to recover the condensate using closed-system equipment and send it to the boiler deaerator for reuse ； If no boiler equipment is available in the plant, it is possible to consider exchanging heat gradually with each heat exchanger in the system, in order to reduce the temperature of the condensate water as much as possible and recover heat from it ； If cooling is required for production or office systems, absorption chillers can be considered to recover the thermal energy from hot water; the efficiency of such chillers is currently around 60%.

The reuse of condensate can be done either in an open or closed system. What we refer to as energy conservation and emission reduction mainly involves making use of the latent heat of condensation from the steam generated as a by-product in chemical production processes (such as in drying exhaust gases). The focus here is on how to utilize low-grade thermal energy, with strict requirements regarding the optimization of heat exchangers and industrial processes