Process water heat recovery
Process water heat recovery
(OP)
We are plastic foam product manufacturer and for this purpose we use molding machines. This kind of process uses steam for heating plastic and water for cooling purposes.
Returning water after process has the temperature of about 70-75 deg C. Cooling water flow is 120 m3/hr. To reuse this water it needs to be cooled down to about 30 deg C. Cooling towers are used to evaporate some water and bring temperature down to required level. Certain percent of returning water is reheated to fulfill our plant steam requirements. We recognize the amount of energy that possibly can be recovered and reused to produce steam, but we are still looking for suitable solution to produce steam and cool process water at the same time.
We are really open to any help and suggestions.
Returning water after process has the temperature of about 70-75 deg C. Cooling water flow is 120 m3/hr. To reuse this water it needs to be cooled down to about 30 deg C. Cooling towers are used to evaporate some water and bring temperature down to required level. Certain percent of returning water is reheated to fulfill our plant steam requirements. We recognize the amount of energy that possibly can be recovered and reused to produce steam, but we are still looking for suitable solution to produce steam and cool process water at the same time.
We are really open to any help and suggestions.





RE: Process water heat recovery
Mark Hutton
RE: Process water heat recovery
RE: Process water heat recovery
Incoming domestic water will be in the range of 50-55F.
RE: Process water heat recovery
For full recovery of heat you will generate around 8,000kg/hr at 120C/0.198MPa steam. However the condensor for this heat pump would need to operate at around 130C. Most refrigerants at that temperature have very high pressure, so this system may not be economical. As an example for ammonia you would be looking at pressure ratio of around 10. The CoP for a heat pump reduces as pressure rato increases, hence the energy input for compressor and capital cost would not make this attractive.
Mark Hutton
RE: Process water heat recovery
RE: Process water heat recovery
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RE: Process water heat recovery
"Lithium Bromide heat pump" ... I think you are refering to an Absorption Chiller.
Your excess heat might also be of use to your neighbours.
I have heard of projects where excess heat from one company is used by other companies in the same industrial area.
But such a thing might be a large step to take...
5MW would heat a fairly large greenhouse for instance.