Abstract: The invention relates to a process for starting up a heat exchanger system for the generation of steam accommodated in a hot gas line, in particular in an exhaust gas line, conveniently in a waste heat boiler, for instance downstream from a gas turbine, for instance for starting up a circulation system steam generator or a continuous flow (once-through) steam generator, conveniently a natural or forced circulation boiler or once-through boiler, in particular a preheater/evaporator/superheater system provided with a start-up heat exchanger upstream via which the supply of feed medium, in particular water or steam, is effected, and which on start-up dispenses first hot steam and finally water to the heat exchanger system, so that the initially pressureless, void heat exchanger system substantially heated to hot gas temperature is continuously brought to its operative state and its operating temperature, as well as a corresponding heat exchanger system.

Abstract: The invention concerns a fluidized bed process for the gasification and combustion of fuels in differently fluidized zones separate from one another, the fuel being charged into a drying and pyrolysis zone with lower fluidization and solids transport downwards, the solids conveyed downwards being conveyed from the lower part of the drying and pyrolysis zone to the lower part of a combustion zone with higher fluidization and solids transport upwards and recirculating, after passing the combustion zone, from the upper zone thereof to the drying and pyrolysis zone, comprising that the solids are conveyed upwards in a combustion zone operated as a fast or turbulent fluidized bed beyond the bed height in the drying and pyrolysis zone and are subsequently forcibly deflected so that the solids drop down on the surface of the bed in the drying and pyrolysis zone as a shower of particles, that the fuel is metered into the shower of particles and that the gases emerging from the combustion zone are passed under use of