LIGNITE DRYING WITH A HEAT RECOVERY CIRCUIT

摘要

The invention relates to a lignite fired steam power plant comprising a water/steam power cycle, a dryer system for drying lignite coal and a heat recovery system for recovering thermal energy from the dryer system. The heat recovery system vaporises condensate against a vapour line of the dryer steam and then compresses the vaporised condensate for use to preheat either or both combustion air or condensate of the water/steam power cycle.

主权项

1. A lignite fired steam power plant comprising:
a water/steam power cycle having:
a pressure series of steam turbines;a condenser at a low pressure end of pressure series of steam turbines configured and arrange to condense steam exhausted from the low pressure end of the pressure series of steam turbines;a first condensate line connected to the condenser; anda low pressure condensate preheat system, in the first condensate line, adapted to preheat condensate from the condenser; a dryer system for drying lignite coal, the dryer system having:
a dryer; anda vapour outlet line for removing vapour from the dryer, a heat recovery system for recovery of thermal energy from the vapour outlet line, the heat recovery system comprising:
a second condensate line, fluidly spanning between the condenser and the first condensate line so as to at least partially bypass the low pressure condensate preheat system;a third condensate line extending from the condenser to the low pressure condensate preheat system so as to bypass at least a portion of the low pressure condensate preheat system and at least a portion of the second condensate line;a condensate evaporator fluidly connected to the vapour outlet line and the third condensate line so as to enable evaporation of a condensate in the third condensate line against condensing vapour in the vapour outlet line;a first compressor, in the third condensate line downstream of the condensate evaporator, adapted to compress the evaporated condensate from the condensate evaporator; anda first heater connected to and downstream of the first compressor for desuperheating and condensing vapour from the first compressor.