Combustion gas routing method for steam heating boiler

摘要

The method involves a steam boiler flue gas extraction system which has gas flues. One flue is in normal exhaust use and the other may have fresh air introduced through deflector boxes to service air pre-heaters, filters, heat by-pass systems, desulphurisation units or cooling towers. The steam boiler has two parallel flue paths (2,3) having deflector pre-heater units (4,5) and various other conversion units connected, for utilisation of waste heat, and cold (6,27) and hot air inlets (7,24) provided with shutters (7,8,23,24). The deflector units are also shuttered (9,10) from the boiler flue. By-pass ducts (13,14) connect the spaces between the shutters in the hot air intakes and flue ducts, and are also shuttered (15,25). In normal operation both channels are open by manipulation of the shutters. When servicing is required in one pre-heater unit, it may be isolated by use of the shutters but the boiler remains in operation through the other.