JohnWeal
Mechanical
- Dec 16, 2012
- 124
We have 2 sludge digesters on a Wastewater Treatment Plant each requiring 250kW in summer and 1050kW in winter to keep the sludge at 38 deg C.
Heat energy is provided by 3 x CHP engines which have individual Pumps that take hot water from the main circuit. However, when a CHP out for maintenance during colder days, one of two boilers will provide supplementary heat. (Each boiler is capable of replacing all 3 CHPs)
The boilers will therefore have no more than 4 weeks operation per year.
Therefore, the boilers require hot after passing through them all year to prevent corrosion and minimise cycling stress.
Are the any typical circuit designs in publications / specifications I can use to provide a basis for design?
The current proposal to allow system operational flexibility has one pair of main distribution circulators, a shunt pump for each boiler, a pump for supplying water to each CHP, a pump for each of the two heat exchangers. The boilers connect to a common discharge and feed hot water at 85 deg C into a vertical low-loss header to decouple from the main distribution circuit which runs at a temperature of 70 deg C (maximum allowed at the sludge heat exchangers)
Be grateful for any advice if anyone has been involved with similar projects.
Best Regards
Heat energy is provided by 3 x CHP engines which have individual Pumps that take hot water from the main circuit. However, when a CHP out for maintenance during colder days, one of two boilers will provide supplementary heat. (Each boiler is capable of replacing all 3 CHPs)
The boilers will therefore have no more than 4 weeks operation per year.
Therefore, the boilers require hot after passing through them all year to prevent corrosion and minimise cycling stress.
Are the any typical circuit designs in publications / specifications I can use to provide a basis for design?
The current proposal to allow system operational flexibility has one pair of main distribution circulators, a shunt pump for each boiler, a pump for supplying water to each CHP, a pump for each of the two heat exchangers. The boilers connect to a common discharge and feed hot water at 85 deg C into a vertical low-loss header to decouple from the main distribution circuit which runs at a temperature of 70 deg C (maximum allowed at the sludge heat exchangers)
Be grateful for any advice if anyone has been involved with similar projects.
Best Regards
