Disclosed is a method for thermally drying pasty products, in particular wastewater sludge, and a belt dryer implementing such a method. The principle consists of partitioning the drying operations and using, for each of the successive operations, a different quality of air: (i) hot air for “searing” the sludge, (ii) low temperature air, then (iii) cold air for quenching the sludge before the extraction of same. Also proposed are loops of air supply circuits making it possible to optimize the energy consumption of the dryer by reusing energy produced within these circuits. Moreover, the loops make it possible to recover unavoidable low temperature energy or cheap energy, further optimising the consumption of the dryer.

Disclosed is a method for thermally drying pasty products, in particular wastewater sludge, and a belt dryer implementing such a method. The principle consists of partitioning the drying operations and using, for each of the successive operations, a different quality of air: (i) hot air for searing the sludge, (ii) low temperature air, then (iii) cold air for quenching the sludge before the extraction of same. Also proposed are loops of air supply circuits making it possible to optimize the energy consumption of the dryer by reusing energy produced within these circuits. Moreover, the loops make it possible to recover unavoidable low temperature energy or cheap energy, further optimising the consumption of the dryer.

A drying machine includes a liquid accumulator, a circulating pump, a radiator tube and a heat absorber tube connected sequentially through pipelines. A radiator housing is provided outside the radiator tube. A heat absorber housing is provided outside the heat absorber tube. A condenser is arranged between the radiator housing and the heat absorber housing. The radiator housing is connected with an air inlet, and the heat absorber housing is connected with a return air inlet. Energy storage material is driven by carrier liquid to flow along the pipelines.

The invention relates to a lignite fired steam power plant comprising a water/steam power cycle and a lignite dryer system having a heat pump circuit configured and arranged to provide heat energy to a lignite dryer of the dryer system. The heat pump includes a dryer heat exchanger, an expansion device and an evaporator heat exchanger connected to the first outlet line so as to enable heat energy transfer from the vapour of the first outlet line to the first working fluid. A compressor is also included in the heat pump circuit. In addition the heat pump circuit is connected to the water/steam power cycle by a steam makeup line from the pressure series of steam turbines and a condensate return line.