DIGESTOR HEAT RECOVERY
In the framework of HORIZON 2020 project "LowUP", a RHeX heat exchanger is used as an energy harvester in a Biodigestor environment.
It is physically mounted on the sludge outlet of the digestor in the sewage treatment plant in Collbató y El Bruc (SPAIN) treating the effluents of the city of Madrid.
It works in conjunction with a heat pump to raise the temperature levels of the thermal energy harvested from the outflowing digestor sludge and heat up the incoming flow to the digestor.
This LowUP project is to be integrated with a remote thermal lab, in order to verify all working conditions for the heat recovery exchanger and the heat pump in a safe environment, without affecting productive necessities of the industrial site.
The heat pump - ptimary exchanger data will be totally integrated with the thermal lab both on cold and hot sinks, in order to assess the available resources from the RHeX heat recovery technology and the loads suitable for the water treatment plant.
Heat pump control will be totally integrated with lab supervision system, remotely connected with the industrial site.
Monitored data from individual technologies (regarding energetic most relevant parameters) will be transmitted to the thermal lab, at the same time,monitored data about the necessities of the load (identified in the process itself) will be transmitted to the lab for emulation and validation of the operation of the recovery plant under relevant working conditions.
The Collbató effluent treatment plant
The target effluent treatment plant is located in Collbató y El Bruc (Barcelona - Spain), is operative since 1999 and is actually used for the depuration, via anaerobic digestion, of residual urban water before being discharged into the nearby river.
The treatment capacity is around 35.000 m3 /day, based on biologic operation of activated sludge which requires to be anaerobically digested at constant temperature of 35ºC for the production of biogas (used for cogeneration purposes or directly burned at torch).
The thermal process of sludge heating is achieved via water-to-sludge heat exchanger, where heating can be provided from recovered waste heat upgraded by means of a heat pump, supported by back-up gas boilers, producing water at 70ºC;
The heat exchanger has an exchanging capacity of over 200 kWth.