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Boilers economizer

This is a term applied to the early freestanding shell boilers of two- and three-pass construction. Originally, they were dry back and later wet back. These boilers superseded the brickset boilers. The earliest economic boilers were also brickset. The gases from the front smokebox returning across the lower external part of the shell were contained within the brick setting to form a third pass. [Pg.345]

Most plants have boilers producing steam for space heating many need steam for other purposes as well. Boiler water requirements for boilers have changed radically over recent years. The old Lancashire and Economic boilers had large heating surfaces and low heat transfer rates scale deposits would do no more harm than reduce their thermal efficiency. [Pg.476]

Further boiler design developments produced various other types of compact, self-supporting, externally fired FT boilers, with the shell mounted over a steel-encased furnace. These designs were loosely called economic boilers and were typically coal- or oil-fired, three-pass boilers with an arched top (the crown sheet) and stayed side-sheets and other flat steel surfaces. [Pg.30]

Economic boiler see also Boiler, fire tube, economic 30 ... [Pg.849]

Askew, T. Selecting Economic Boiler-Water Pretreatment Equipment, Chemical Engineering, Apr. 16, 1973, p. 114. [Pg.235]

Oxygen, even in very small amounts, may cause serious corrosion in feedwater lines, stage heaters, economizers, boiler metal, steam operated equipment and condensable piping. It must, therefore, be removed from the closed system. The solubility of oxygen varies with both pressure... [Pg.369]

Selection of the high pressure steam conditions is an economic optimisation based on energy savings and equipment costs. Heat recovery iato the high pressure system is usually available from the process ia the secondary reformer and ammonia converter effluents, and the flue gas ia the reformer convection section. Recovery is ia the form of latent, superheat, or high pressure boiler feedwater sensible heat. Low level heat recovery is limited by the operating conditions of the deaerator. [Pg.353]

In fossil fuel-fired boilers there are two regions defined by the mode of heat transfer. Fuel is burned in the furnace or radiant section of the boiler. The walls of this section of the boiler are constmcted of vertical, or near vertical, tubes in which water is boiled. Heat is transferred radiatively from the fire to the waterwaH of the boiler. When the hot gas leaves the radiant section of the boiler, it goes to the convective section. In the convective section, heat is transferred to tubes in the gas path. Superheating and reheating are in the convective section of the boiler. The economizer, which can be considered as a gas-heated feedwater heater, is the last element in the convective zone of the boiler. [Pg.358]

Gas leaving the converter is normally cooled to 180—250°C using boiler feedwater in an "economizer." This increases overall plant energy recovery and improves SO absorption by lowering the process gas temperature entering the absorption tower. The process gas is not cooled to a lower temperature to avoid the possibiUty of corrosion from condensing sulfuric acid originating from trace water in the gas stream. In some cases, a gas cooler is used instead of an economizer. [Pg.185]

Standard stainless steels have significantly greater corrosion resistance to oleum than carbon steel, but higher price may make these materials less economical, except for special services such as valves, Hquid distributors, oleum boilers, etc. [Pg.188]

A low calorific value gas, which includes nitrogen from air, could be produced for boiler or turbine use in electric power production, or an intermediate calorific value gas containing no nitrogen for an industrial fuel gas, or synthesis gas for chemical and methane production could be provided. This approach which has been studied in Russia, Europe, Japan, and the United States, is stiU noncommercial in part because it is not economically competitive. [Pg.236]

Feed Composition. Feed composition has a substantial effect on the economics of a distillation. Distillations tend to become uneconomical as the feed becomes dilute. There are two types of dilute feed cases, one in which the valuable recovered component is a low boiler and the second when it is a high boiler. When the recovered component is the low boiler, the absolute distillate rate is low but the reflux ratio and the number of plates is high. An example is the recovery of methanol from a dilute solution in water. When the valuable recovered component is a high boiler, the distillate rate, the reflux relative to the high boiler, and the number of plates all are high. An example for this case is the recovery of acetic acid from a dilute solution in water. For the general case of dilute feeds, alternative recovery methods are usually more economical than distillation. [Pg.175]

Boiler Economizers. Heat exchangers that use boiler flue gases to preheat the boiler feedwater are termed boiler economisers. [Pg.226]

For some applications, either steam or electricity is simply not available and this makes the decision. It is rarely economic to install a steam boiler just for tracing. Steam tracing is generally considered only when a boiler already exists or is going to be installed for some other primary purpose. Additional electric capacity can be provided in most situations for reasonable costs. It is considerably more expensive to supply steam from a long distance than it is to provide electricity. Unless steam is available close to the pipes being traced, the automatic choice is usually electric tracing. [Pg.1013]

Process Water Purification Boiler feed water is a major process apphcation of RO. Sealants and colloids are particularly well rejected by membranes, and TDS is reduced to a level that makes ion exchange or continuous deionization for the residual ions very economic. Even the extremely high quahty water required for nuclear power plants can be made from seawater. The iiltra-high quahty water required for production of electronic microcircuits is usually processed starting with two RO systems operating in series, followeci by many other steps. [Pg.2034]


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See also in sourсe #XX -- [ Pg.399 ]




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