A method of and an apparatus for shot peening an inner surface of a stainless steel tube. A set of at least two electromagnets is arranged around the stainless steel tube and has an iron core with an air gap adjacent to the stainless steel tube. At least one magnetic shot particle is provided inside the stainless steel tube. A controller controls the activation of the electromagnets according to a predetermined sequence, so as to cause the at least one magnetic shot particle to repeatedly hit the inner surface of the tube so as to shot peen the inner surface.
C21D 7/06 - Modifying the physical properties of iron or steel by deformation by cold working of the surface by shot-peening or the like
B23P 9/04 - Treating or finishing by hammering or applying repeated pressure
C21D 9/14 - Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articlesFurnaces therefor for tubular bodies or pipes wear-resistant or pressure-resistant pipes
A radiant superheater (26) arranged to hang at the upper portion of a furnace (12) of a boiler. The radiant superheater (26) is substantially planar and includes a first vertical (34) pass, a first connection pass (36), a second vertical pass (38), a third vertical pass (40), a second connection pass (42), and a fourth vertical pass (44). Each vertical pass includes an upper end and a lower end. The vertical passes are connected in series, so that steam to be superheated enters at the upper end of the first vertical pass and flows through the first vertical pass and from the lower end of the first vertical pass via the first connection pass to the lower end of the second vertical pass and through the second vertical pass and from the upper end of the second vertical pass to the upper end of the third vertical pass and through the third vertical pass and from the lower end of the third vertical pass via the second connection pass to the lower end of the fourth vertical pass and through the fourth vertical pass, to be discharged from the upper end of the fourth vertical pass. The first connection pass is arranged below the second connection pass so as to shield the second connection pass from radiation from the lower portion of the furnace.
A solar heat receiver system includes multiple vertically extending solar heat receiving tubes for transferring solar heat to a heat transfer medium flowing through the solar heat receiving tubes, a rigid support structure, two first connectors to connect two spaced- apart portions of the solar heat receiving tubes to the rigid support structure so as to prevent horizontal movement of the two spaced-apart portions of the solar heat receiving tubes, and a second connector for connecting at least one intermediate portion of the solar heat receiving tubes to the rigid support structure, which intermediate portion is located between the spaced- apart portions. The second connector allows a limited amount of horizontal movement of the at least one intermediate portion of the solar heat receiving tubes due to a thermally induced bow of the solar heat receiving tubes.
A method of selective catalytic NOx reduction in a power boiler (10) and a power boiler with selective catalytic NOx reduction. Fuel is combusted in a furnace (12) of the boiler and a flue gas stream that includes NOx is generated. The flue gas stream is conducted from the furnace along a flue gas channel to a stack (46). The flue gas stream is cooled in a heat recovery area (34), including an economizer section (38), arranged in the flue gas channel. At least a portion of the NOx is reduced to N2 in an NOx catalyst arranged in the flue gas channel downstream of the economizer section. The flue gas is further cooled, and heated air is generated in a gas -to-air heater (50) arranged in the flue gas channel downstream of the economizer section and upstream of the NOx catalyst. The gas -to -air heater may be a tubular air heater or a heat exchanger with a recirculating heat transfer fluid.
F01K 13/00 - General layout or general methods of operation, of complete steam engine plants
F22B 1/18 - Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines
F22B 37/00 - Component parts or details of steam boilers
F01K 3/24 - Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein having heaters with heating by separately-fired heaters
A method of providing a weld overlay structure (10) on a heat transfer tube (12) or a membrane surface. A first continuous bead portion (26, 40) of an overlay material is applied onto the heat transfer tube or membrane surface by using a weld head to melt the overlay material. A second continuous bead portion (26', 40') of the overlay material is applied onto the heat transfer tube or membrane surface by using a weld head to melt the overlay material, in which the second bead portion partially overlaps with the first bead portion, forming a groove (30) between the first bead portion and the second bead portion. A third continuous bead portion (32, 42) of an overlay material is applied onto the heat transfer tube or membrane surface by using a weld head to melt the overlay material into the groove (30) between the first bead portion and the second bead portion, so as to form a relatively smooth surface.
A method of controlling a boiler plant during a switchover period from an air- combustion mode to an oxygen-combustion mode. The method includes steps of feeding fuel into a furnace of the boiler plant at a rate determined by a fuel feeding scheme, feeding air into the furnace at a rate determined by a descending air feeding scheme, feeding substantially pure oxygen into the furnace at a rate determined by an ascending oxygen feeding scheme, and recirculating flue gas into the furnace at a rate determined by an ascending flue gas recirculating scheme. The fuel feeding scheme, the air feeding scheme and the oxygen feeding scheme are such that the fuel is combusted and the flue gas containing residual oxygen is produced. Also, the fuel feeding scheme, the air feeding scheme and the oxygen feeding scheme are such that the content of residual oxygen in the flue gas is, during at least a portion of the switchover period, greater than during any of the air-combustion mode and the oxygen-combustion mode. The method makes it possible to reduce CO2 emissions and O2 consumption quickly during the short switchover period.
A circulating fluidized bed combustor arrangement includes (a) a circulating fluidized bed reactor in which (i) a combustion chamber combusts a fuel material in a suspension of solid particles of a circulating fluidized bed, (ii) a first cyclone separator arrangement receives a mixture of gases and solid particles from the combustion chamber for separating a first fraction of the solid particles from the exhaust gases, and (iii) a solid particle return system connected to the first cyclone separator returns separated solid particles to the combustion chamber, (b) a heat transfer section including a water/steam heat exchanger section arranged after the first cyclone separator arrangement in the exhaust gas flow path, (c) a heat recovery device provided in connection with the combustion chamber, the first cyclone separator arrangement and the heat transfer section being arranged for recovering heat resulting from the combustion process in the combustion chamber, (d) a selective catalytic reduction system arranged in the exhaust gas flow path, after the heat transfer section, for removing NOx from the exhaust gas, (e) a device for injecting NOx reducing agent into the exhaust gases upstream of the selective catalytic reduction system, and (f) a second cyclone separator arrangement provided downstream of the first cyclone separator arrangement and upstream of the heat transfer section, in which a second fraction of the solid particles is separated form the exhaust gases.
F23C 10/00 - Apparatus in which combustion takes place in a fluidised bed of fuel or other particles
F23C 10/10 - Apparatus in which combustion takes place in a fluidised bed of fuel or other particles with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases the separation apparatus being located outside the combustion chamber
F23J 15/00 - Arrangements of devices for treating smoke or fumes
F23J 15/02 - Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material
A wall construction for a boiler arrangement (10). The boiler arrangement is formed of at least a furnace (12) and a separator (16). The furnace has a grid, a bottom part, and an upper part. The separator is arranged by conduits (70) in flow communication with both the upper part and the bottom part of the furnace. The conduits, together with the separator, form an external circulation of bed material. The upper part of the furnace has four vertical walls, and the bottom part of the furnace has a height and four walls extending from the grid up to the vertical walls. The wall construction includes at least one hollow beam being attached to a wall of the bottom part of the furnace and extending substantially over the entire height of the bottom part, and the at least one hollow beam being in flow communication with the external circulation for returning bed material into the furnace.
F23C 10/10 - Apparatus in which combustion takes place in a fluidised bed of fuel or other particles with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases the separation apparatus being located outside the combustion chamber
F23C 10/18 - Apparatus in which combustion takes place in a fluidised bed of fuel or other particles DetailsAccessories
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