Power plants boiler designs

Power plant boilers are either of the once-through or dmm-type design. Once-through boilers operate under supercritical conditions and have no wastewater streams directly associated with their operation. Drum-type boilers operate under subcritical conditions where steam generated in the drum-type units is in equilibrium with the boiler water. Boiler water impurities are concentrated in the liquid phase. Boiler blowdown serves to maintain concentrations of dissolved and suspended solids at acceptable levels for boiler operation. The sources of impurities in the blowdown are the intake water, internal corrosion of the boiler, and chemicals added to the boiler. Phosphate is added to the boiler to control solids deposition. 

Certain restrictions imposed by nature must be taken into account when designing a new process or analyzing an existing one. You cannot, for example, specify an input to a reactor of 1000 g of lead and an output of 2000 g of lead or gold or anything else. Similarly, if you know that 1500 Ibn of sulfur is contained in the coal burned each day in a power plant boiler, you do not have to analyze the ash and stack gases to know that on the average 1500 lb , of sulfur per day leaves the furnace in one form or another. 

CLC technology is particularly suitable for coal-fired power plants because the reactor loop can be used in two different configurations. In the first case, the CLC occurs with syngas that is previously produced in a coal gasification plant and the power plant is designed as the typical IGCC so that the CLC is carried out at pressurized conditions, as already discussed for NGCC. In the second case, the CLC reactors can substitute the coal boiler and the OCs react with the solid fuel as proposed for the isG-CLC and the CLOU mechanisms. 

Catalysts may therefore be designed for nse in specific duties. For power plant, the design must balance the reaction rates of NOX reduction and sulfur dioxide oxidation in the restricted range of temperature of flue gas leaving the boiler, or at the dust and sulfur dioxide removal stages. A low activity catalyst that reaches maximum NOX reduction between, say 380°-400°C, can be more efficient than a catalyst that is more active between 300°-350°C because, overall, it produces less sulfur trioxide at the fixed operating temperature. ... 

The thermal power plant uses a fired boiler for conversion of fuel to heat. It can be said that there is a design of fired boiler to suit almost all types of fuels, including wastes and vegetable and industrial byproducts. Generally, for oils and gases these can be more readily converted to power in diesels or gas turbines and would not be considered for thermal power plant, unless the station was of significant size. 

Power boilers typically produce one kWh of electricity for every 8,500 to 9,500 Btu (8,968-10,023 kJ) gross fuel input, providing a net thermal efficiency of 34 to 40%. (As a rule, utility power plants are seldom more than 34 to 36% efficient, although some modem designs may go as high as 40%.)... 

All large industrial WT and power boiler plants utilize deaerators and supplement the DO removal process by means of a suitable chemical oxygen scavenger. Many midsize factories operating FT boilers or FT-WT boiler combinations also employ mechanical deaeration. This is especially common in the United States, Germany, and several other industrialized countries where boiler design custom and practice virtually dictate that a deaerator be included in almost every midsize and larger boiler plant facility. 

Mixed plastics waste appears to be well suited for use in energy recovery, either as a co-eombustion fuel in a power plant designed for solid fuels, or as the sole fuel in speeially designed plants. This paper reports test results on the co-combustion of mixed household plasties with eoal. The tests were performed in a bubbling fluidised bed low-pressure steam boiler. The results show that both inorganic and organic total specific emissions were lower for mixed household plasties than for coal. Tabulated data are presented. 3 refs. 

A gas turbine power plant requires hot, high-pressure gases produced by burning oil or natural gas. The hot exhaust gases can be used to create steam in a boiler system. The efficiency can approach 90% if the system is properly designed. 

Furnaces of tbis type, such as the steam locomotive furnace—boiler design, had the obvious disadvantage that pressure was limited to ca 1 MPa (150 psi). The development of seamless, thick-wall tubing for stationary power plants (ie, water-tube furnaces) and other engines for motive power, such as diesel—electric, has in many cases eclipsed the fire-tube boiler. For applications calling for moderate amounts of lower pressure steam, however, the modem fire-tube boiler continues to be the indicated choice (5). 

A key development in water-tube furnace design was the Babcock and Wilcox boiler of 1877 (Fig. 2) (3). This can be considered the direct evolutionary ancestor of the 1000 MW steam power plants a century later (see Steam). 

Engineering Construction Industrial Plant Design Development Energy Methanol Equipment Power Systems Manufacturer Cogeneration Electric Plant Operation Independent Power Plant Operation Renewable Energy Technology Fluidized Bed Conventional Boilers... 

The test was in response to problems resulting from TDF burning in a FBC boiler retrofitted from a spreader/stoker design, and located at a Wisconsin power plant.16 Problems during the commercial test indicated that better tramp metal removal was necessary, combustion was not adequate, and that the particulate control device, an electrified filter bed, was not commensurate with the ash levels generated.16... 

Tires acquired from the "flow" are stored in a specially designated area near the existing tire pile. The tires are fed into a hopper located adjacent to the tire pile. An automated tire feed system singulates tires (spaces them individually) up to 800 tires per hour, to a conveyor belt traveling 420 feet up a hill to the power plant. Tire feed rate averages 350 to 400 tires per hour to each boiler.1... 

Four plants are reported to have considered burning TDF supplementally in boilers with a primary fuel of biomass or refuse-derived fuel. These plants are listed in Table 7-1. Two RDF fired power plants are attempting to obtain permits to bum tires.10 One biomass burner in Maine is reportedly in the permit process, and has been designed with the capability of burning tires.12 Personnel at the State Air Pollution Agency in South Carolina indicated that several municipalities had tried, unsuccessfully, in the past to bum TDF in their RDF incinerators.11 No information was obtained on boiler configuration or air pollution control equipment. 

Boilers are available in two basic designs a fire tube, in which water circulates in tubes heated externally by fire and a water tube, in which hot gases from fire pass through the tubes in the boiler. Fire-tube boilers are generally limited in size to approximately 12,000 kg/h (25,000 lb/h) and to about 20 bar (250 psig). Their size and pressure limitations preclude their use in large industrial facilities or in power plants. 

In this demonstration plant, the boiler feedwater can be preheated by geothermal heat if available. Depending on the availability and temperature of the geothermal heat in the area, the geothermal plant s design would vary. If the groundwater temperature exceeds 150°C (302°F), a "flash steam" power plant would be used, and if it is between 100 and 150°C (212 and 302°F), a "binary cycle" power plant would be used. 

Smith, M. Effects of Condenser Design upon Boiler Feedwater Essergy Costs in Power Plants. M.S. Thes., Ga. Tech, 1981. 

Smith, M. S., "Efforts of Condenser Design Upon Boiler Feedwater Essergy Costs in Power Plants," Master s Thesis, GA Inst, of Technology, Atlanta, GA (1981). 

A power plant for generating electricity is one part of a plant-design proposal. Two alternative power plants with the necessary capacity have been suggested. One uses a boiler and steam turbine while the other uses a gas turbine. The following informa-... 

Steam power plants produce electricity with rather low thermal efficiency. An increase in efficiency leads to savings in fuel costs and minimizes environmental effects. The two basic approaches in increasing the thermal efficiency of a cycle are (i) design a process that transfers heat to the working fluid at high temperature in the boiler and (ii) design a process that transfers heat to the working fluid at low temperature in the condenser. These may decrease the temperature differences, and hence the level of irreversibility. 

The suspended superheater below the furnace roof worked well in regulating the steam temperature. Three 75 t/h CFBC boilers of similar design have been operating in Anshan Second Thermal Power Plant during... 

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