Abstract: A method and a device for temperature measurement of the fluid at the outlet from an evaporator in a boiler of benson type, wherein the evaporator includes one or more inlet headers which are supplied with water passed on to evaporator tubes which communicate with a heat-transferring medium and wherein the water is transformed into a fluid which is then via evaporator stubs passed to one or more outlet headers of the evaporator, the temperature of the fluid being measured with the aid of temperature sensors which are placed on adjacently located evaporator stubs for a number of important and critical parts of the boiler, the measured values for each part being supplied to median value selectors whereafter each median value is supplied to a maximum selector, whereby the maximum temperature (t.sub.max) of any of the outlets from the evaporator is obtained, and to a means temperature (t.sub.mean) of the fluid at the outlet of the evaporator is obtained.

Abstract: In a method and device for controlling power output during combustion in a pressurized fluidized bed, energy developed is taken out by heat transfer surfaces and a gas turbine, and heat is utilized in a steam turbine. The heat transfer surfaces include a high pressure section with one evaporator and a low pressure section with at least one intermediate superheater. In case of changes in the power output, the bed depth of the fluidized bed is varied, whereby heat transfer surfaces included in the evaporator are exposed or covered by the bed and production of high pressure steam, evaporation power, is controlled. Heat taken from the fluidized bed is controlled by controlling the temperature difference between the bed and low pressure stream flowing in the intermediate superheaters. High pressure steam, produced in the evaporator is superheated in a heat exchanger arranged outside the bed by low pressure steam from the intermediate superheaters before it is expanded in a high pressure steam turbine.

Abstract: The invention relates to a power plant for combustion of a fuel, for example carbon, in a combustion chamber (2) in a bed (10) of fluidized particulate material, primarily a PFBC power plant. The plant includes a multi-stage steam turbine (13) and an intermediate superheater (12) for superheating steam between the turbine stages. The combustion chamber (2) is divided into a first and a second part (2a, 2b) by a wall (4) having one or more openings (42, 43) which takes up a minor part of the cross-section in the bed region and makes possible a limited exchange of bed material. The first part (2a) includes a nest of boiler tubes (11) for generating steam. The second combustion chamber part (2b) includes a nest of boiler tubes (12) for intermediate superheating of steam between the turbine stages. The combustion chamber parts (2a, 2b) are each connected to a fuel supply system (20, 21, 22 and 23, 24, 25, respectively).