A surface condenser is a commonly used term for a water cooled shell and tube heat exchanger installed on the exhaust steam from a steam turbine in thermal power stations. These condensers are heat exchangers which convert steam from its gaseous to its liquid state at a pressure below atmospheric pressure. Where cooling water is in short supply, an air cooled condenser is often used. An air cooled condenser is however, significantly more expensive and cannot achieve as low a steam turbine exhaust pressure (and temperature) as a water cooled surface condenser.
Why it is required
The canada goose steam turbine itself is canadian goose jacket a device to convert the heat in steam to mechanical power. The difference between the heat of steam per unit mass at the inlet to the turbine and the heat of steam per unit mass at the outlet from the turbine represents the heat which canada goose uk black friday is converted to mechanical power. Therefore, the more uk canada goose outlet the conversion of heat per pound or kilogram of steam canada goose store to mechanical power in the turbine, the better canada goose black friday sale is its efficiency. By cheap canada goose uk condensing the exhaust steam of a turbine at a pressure below atmospheric pressure, the steam pressure drop between the inlet and exhaust of the turbine is increased, which increases the amount of heat available for conversion to mechanical power. Most of the heat liberated due to condensation of the exhaust steam is carried away by the cooling medium (water or air) used by the surface condenser. The shell is fabricated from carbon steel plates and is stiffened as needed to provide rigidity for the shell. When required by the selected design, intermediate plates are installed to serve as baffle plates that provide the desired Canada Goose Parka flow path of the Canada Goose Coats On Sale condensing steam. The plates also provide support that help prevent canada goose coats sagging of long tube lengths.
At the Canada Goose Online bottom of the shell, where the condensate collects, an outlet is installed. In some designs, a sump (often referred to as the hotwell) is cheap Canada Goose provided. Condensate is pumped from the outlet or buy canada goose jacket the hotwell for reuse as boiler feedwater.
For most water cooled surface Canada Goose Jackets condensers, the shell is under vacuum during normal operating conditions.
For water cooled surface condensers, the shell’s internal vacuum is most commonly supplied by and maintained by an external steam jet ejector system. Such an ejector system uses steam as the motive fluid to remove any non condensible gases that may be present in the surface condenser. The Venturi effect, which is a particular case of Bernoulli’s principle, applies to the operation of steam jet ejectors. The inlet end of each tube is also bellmouthed for streamlined entry of water. This is to avoid eddies at the inlet of each tube giving rise to erosion, and to reduce flow friction. Some makers also recommend plastic inserts at the entry of tubes to avoid eddies eroding the inlet end. In smaller units some manufacturers use ferrules to seal the tube ends instead of rolling. To take care of length wise canada goose clearance sale expansion of tubes some designs have expansion joint between the shell and the tube sheet allowing the latter to move longitudinally. The use of copper bearing alloys such as brass or cupro nickel is rare in new plants, due to environmental concerns of toxic copper alloys. Also depending on the steam cycle water treatment for the boiler, it may be desirable to avoid tube materials containing copper. Titanium condenser tubes are usually the best technical choice, however the use of titanium condenser tubes has been virtually eliminated by the sharp increases in the costs for this material. The tube lengths range to about 85 (26 m) canada goose uk outlet for modern power plants, depending on the size of the condenser. The size chosen is based on transportability from the manufacturers’ site and ease of erection at the canada goose uk shop installation site. The waterbox is usually provided with man buy canada goose jacket cheap holes on hinged covers to allow inspection and cleaning.
These waterboxes on inlet side will also have flanged canada goose clearance connections for cooling water inlet butterfly valves, small vent pipe with hand valve for air venting at higher level, and hand operated drain valve at bottom to drain the waterbox for maintenance. Similarly on the outlet waterbox the cooling water connection will have large flanges, butterfly valves, vent connection also at higher level and drain connections at lower level. Similarly thermometer pockets are located at inlet and outlet pipes for local measurements of cooling water temperature. This water, depending on its chemical composition, canada goose factory sale will act as an electrolyte between the Canada Goose online metallic composition of tubes and water boxes. This will give rise to electrolytic corrosion which will start from more anodic materials first.
Sea water based condensers, in particular when sea water has added chemical pollutants, have the worst corrosion characteristics. River water with pollutants are also undesirable for condenser cooling water.
The corrosive effect of sea or river water has to be tolerated and remedial methods have to be adopted. One method is the more info use of sodium hypochlorite, or chlorine, to ensure there is no marine growth on the pipes or the tubes. This practice must be strictly regulated to make sure the circulating water returning to the sea or river source is not affected.
On the steam (shell) side of the condenser:
The Canada Goose Outlet concentration of undissolved gases is high over air zone tubes. Therefore these tubes are exposed to higher corrosion rates. uk canada goose Some times these tubes are affected by stress corrosion cracking, if original stress is not fully relieved during manufacture. https://www.canadagooseonlineshop.co.uk To overcome these canada goose coats on sale effects of corrosion some manufacturers provide higher corrosive resistant tubes in this area Canada Goose sale.