Abstract: A pneumatic transportation system for transferring particulate material from a storage container at one pressure level to a receiving unit at another pressure level (e.g. in a feeding system for bed material to a combustion chamber of a PFBC plant). The transportation system incorporates a material feeder comprising a housing having a rotor containing two material chambers. The end walls of the housing and the rotor have cooperating sealing surfaces. The inlet opening of one material chamber is positioned opposite to an inlet opening in the upper end wall of the housing, when the outlet opening of the other material chamber is positioned opposite to an outlet opening in the lower end wall of the housing. After rotation of the rotor the inlet opening of the material chamber will be positioned opposite to the inlet opening and the outlet opening of the chamber will be positioned opposite to the outlet opening. Between the actual material chambers and the outlet openings there are cut-off valves.

Abstract: Apparatus for conveying particulate material from a pressurized container (1) to a collecting container (20) under considerably lower pressure, comprises conduit means (17) arranged between the containers (1 and 20) and typically built up of a number of tube parts in such a way that, at the transition between the tube parts, a gas/particulate material stream flowing therethrough is bent through an angle, usually either 90.degree. or 180.degree..

Abstract: A PFBC plant which includes a gas cleaner located inside an air-filled pressure vessel is provided with means to detect erosion damage in the gas cleaner. Portions of the wall of the gas cleaner which are exposed to erosion damage are surrounded by a space defined by a gas-tight mantle. The mantle has an opening which provides a connection between the defined space and the air in the pressure vessel. Adjacent the opening is a device for indicating when air flows through the opening into the defined space.

Abstract: A plant for combustion of a particulate fuel in a fluidized bed in a combustion chamber has the fuel supplied into the bottom of the combustion chamber by means of a pneumatic transportation system via nozzles. Fuel for the plurality of nozzles is transported through a duct to a distributor and from there via individual conduits to the nozzles of the combustion chamber. These conduits include flow-inhibiting, pressure-drop generating means, by means of which a pressure drop is generated between the distributor and the combustion chamber. These pressure-drop inducing means influence the velocity of flow and hence the transport capacity of the transport gas so that a desired, normally uniform, distribution of fuel to the bed is secured.

Abstract: The conveying properties of a particulate fuel during pneumatic transportation to a fluidized bed in a combustion plant, are improved by at least surface drying of the fuel. A calcium-containing bed material is withdrawn from the bed under such conditions that the bed material is calcined to form CaO. This withdrawn bed material is crushed and mixed with fuel, whereby the CaO absorbs water from the fuel in an exothermic reaction forming calcium hydroxide, Ca(OH).sub.2, the released heat evaporating moisture from the fuel. The fuel particles will have reduced surface moisture which reduces the risk of clogging during pneumatic feeding of fuel to a combustion chamber. Due to the intimate contact between the fuel particles and the crushed bed material, the tendency towards reaction between sulfer in the fuel and the bed material increases.

Abstract: A pneumatic transportation system for particulate material, such as powdered or granular materials, with a switching valve (7) for selection of different transport paths within the transportation system. The valve includes a turnable rotor (15) with a bore or a compartment (23), the inner part of which constitutes a blind space for forming an erosion-preventing cushion (26) of powder. An upstream conduit (6) is connected to the valve housing (14) opposite to the blind space of the compartment (23). In dependence on the position of the rotor (15), the compartment (23) or a channel (24) adjacent to this forms a connection to any one of several downstream conduits (20, 21) connected to the valve housing (14).

Abstract: The separating efficiency of a cyclone separator used for removing solid particles from a gas stream (for example ash particles from the combustion gas which is passed to a gas turbine) is increased by retarding the particles before they arrive at the cyclone and thereafter accelerating them over a short distance before they enter the cyclone. In this way large particles will have a lower speed than small particles when entering the cyclone. Despite a high velocity of the transport gas and a high inlet velocity for small particles, it is possible to obtain an inlet velocity for larger particles which is desirably low from the point of view of reducing erosion of the cyclone separator. The separation of fine particles is improved. The retardation of the particles may take place in a T-shaped branch pipe, which has one branch connected to the cyclone, a second branch connected to a conveying pipe and a third branch which is formed as a blind space.

Abstract: The invention relates to a method of igniting, upon start-up, a combustion chamber (8) in a power plant with combustion of fuel in a fluidized bed (14). The air flow through the nozzles (13) of the combustion chamber bottom (12) for fluidization of the bed (14) and for combustion of the fuel can be reduced upon start-up; bed material, which is heated to the ignition temperature of a start-up fuel, is transferred from a storage container (40) to the combustion chamber (8), and fuel is supplied to the bed (14). In those cases where the air flow has been reduced during the transfer of the bed material, it is increased again when the fuel is supplied. The invention also relates to a power plant having means for temporarily bypassing the nozzles (13) of the combustion chamber bottom (12) while transferring hot bed material from a storage container (40) to the combustion chamber (8), and a fuel system (30-38) for the supply of fuel to the combustion chamber (8).

Abstract: To prevent the tube to a pressure measuring means from being blocked by solid material mobile in a pressure container, a small part of the clean pressure medium from a source of such medium is injected into the tube so that the tube is continuously purged with clean pressure medium. By locating the pressure medium input at a suitable position along the tube relative to the pressure measuring means, the desired purging of the tube is obtained without appreciably increasing the pressure in the tube, and thus minimizing possible errors in measurement of the pressure. If, for example, pressure medium is passed into a pressurized combustion chamber through a surrounding pressurized container, and the tube to the pressure-measuring means passes through said surrounding pressurized container, the clean pressure medium can be bled into the tube through a hole bored in the side of the tube within the pressurized container.

Abstract: A power plant with a combustion chamber (8) with a fluidized bed (14) and a device for adjusting the bed height, comprising a storage container (21) for bed material, the storage container (21) being connected to the combustion chamber (8) by a first conduit (22) for feeding out bed compound from the combustion chamber (8) to the container (21) and a second conduit (23) for returning bed compound from the container (21) to the combustion chamber (8). The storage container (21) is connected, via a conduit (34) with a valve, to a space having lower pressure than the pressure in the combustion chamber (8). The return conduit (23) is connected, via a conduit (67) with a valve, to a pressure gas source (10) having higher pressure than the pressure in the combustion chamber (8). Transport of bed compound from the combustion chamber (8) is achieved by reducing the pressure in the storage container (21).

Abstract: A gas turbine plant comprises a compressor, a turbine and, therebetween, a pressurized container containing a combustion chamber with a fluidized bed. The plant further comprises a valve means for shutting off the compressor and the turbine, respectively, from the combustion chamber at a sudden load drop out and a valved by-pass duct for direct connection of the compressor and the turbine.At a rapid load drop out, when the valve means are operated to shut off the combustion chamber from the compressor and the turbine and there is a direct connection between the compressor and the turbine, the fluidized bed of the combustion chamber is passivated, by short-circuiting, by means of a further valve means which connects the pressurized container supplying combustion air to the inlet side of the combustion chamber with the outlet side of the combustion chamber, so that the fluidized bed collapses and the air flow through it is interrupted.

Abstract: In a fluidized bed plant for the combustion of impure solid fuel in the presence of an absorbent material which absorbs and neutralizes the impurities, in particular sulfur, the supply of absorbent material to the fluidized bed is controlled in dependence on the impurity content in the exhaust gases leaving the fluidized bed. To achieve a rapid control, at least part of the absorbent material is supplied to the fluidized bed in a finely ground state. The bed material may consist of coarse-grained absorbent material or a chemically inactive material, or a mixture of these. Coarse-grained absorbent material which is discharged from the fluidized bed can have its particle size reduced and be passed back to the fluidized bed.

Abstract: An electrical power plant with gas turbine plant operating with a fluidized bed combustion chamber and a gas turbine-driven electrical generator includes at least one device for rapidly influencing the speed of the generator upon synchronizing the generator for connecting its output into an electrical network. This device may comprise a resistor connectible to the generator output to decelerate the generator, an electrical machine connectible to the generator which is capable of accelerating or decelerating the generator, flow control valves in various gas conduits to rapidly influence the gas flow through one or more of the turbines thereof, an injection nozzle for the injection of water or steam into the combustion gases from the combustion chamber, or an auxiliary combustion chamber for augmenting the thermal output of the fluidized bed combustion chamber.

Abstract: Apparatus for controlling the flow of fuel supplied via a regulating valve to a gas turbine plant having a compressed-gas generating unit and a power turbine which is driven by the gas from the generating unit. The function of the controlling apparatus is to reduce or cut off the supply of fuel in the event of an overspeed condition of the power turbine. The apparatus includes a first means which is responsive to the angular velocity of a rotor in the power turbine, and a second means which is responsive to the angular acceleration of such rotor. The control means is jointly responsive to the output signals provided by the first and second means so as to control the valve and reduce the rotor's angular velocity when the output signals provided by both the first and second means concurrently exceed predetermined values.