Cool the gas with circulating cooling water
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I would like to ask everyone: I want to use the factory’s circulating cooling water to cool flue gas at 200°C. If a shell-and-tube heat exchanger is used, what is generally the temperature difference between the liquid inlet (lower temperature) and the gas outlet (lower temperature)? Also, may I ask what are the typical design temperatures for the inlet and outlet of the circulating cooling water in a factory? My search results show 33 for imports and 43 for exports, with a temperature difference of around 10. Is that correct? I would appreciate some advice from those who are more experienced.
Why use circulating water to cool flue gas? It wastes circulating water and increases the load on the cooling tower; can’t you install a economizer for the flue gas? It can be done using air or water, which helps save energy.
It’s such a waste; it doesn’t fit the current call for energy conservation. Think of other uses – doesn’t your company need hot water?
Generally, in northern regions, the inlet and outlet temperatures of circulating water in design are 42°C and 32°C respectively, with a temperature difference of 10°C℃
From an energy-saving perspective, low-pressure steam can be generated using flue gas. From an energy-saving perspective, using recycled cooling water is also not appropriate, as the temperature difference is too large, making it difficult to design the heat exchanger.
Reply to 1# stony_wanghc: The pressure of the circulating water has a significant impact on the outlet temperature; in western Inner Mongolia, it is 25 degrees in summer and 10 degrees in winter. Cool the flue gas; if the flue gas flows through the shell side, I need to consider the impact of dust, tar, and other substances adhering to the tube walls on heat transfer, as well as the issues related to cleaning during maintenance.
The return water temperature should not be too high, as this can lead to scaling and affect water quality
Thank you all above; I’ve learned so much!
The inlet temperature is 25 degrees, while the outlet temperature depends on the process requirements.
Some circulating water inlets are designed for 32 degrees. We need to consider issues related to the northern and southern areas as well as the type of cooling tower, right?