Power plant steels

The environmental pollution in Ukraine has reached critical levels. Vehicles, power plants, steel mills and nonferrous metallurgy works are the major air polluters. Pesticides are responsible for much of the harm done to human health. 

The environmental pollution in transition economy countries has reached critical levels. Vehicles, power plants, steel mills and nonferrous metallurgy works are the major air polluters. Pesticides are responsible for much of the harm done to human health. Water pollution continues on a large scale. Very often the situation is disastrous because this country has a combination of energy-intensive industries, thermal power generation, and intensive agriculture, further aggravated by Chernobyl. 

It is claimed that the recovery of C02 from flue gases emitted by power plants, steel mills, cement kilns and fermentation could become increasingly viable. C02 is not very diluted in these flue gases, with concentration ranging from 10 to 30%. For further utilisation, C02 needs first to be separated and captured, or at least concentrated. Membrane technology based on polymer materials could be promising, but needs much more selective materials. 

These two simple conversions will cover a large part of the stationary equipment. Gas fired home furnaces, water heaters, and stoves will all be handled in this simple manner at low cost. Coal and oil fired equipment will be less simple to convert. It will require the purchase of a low cost gas burner to replace the coal grates and oil injectors. Examples of industrial processes that can be converted in this simple manner include power plants, steel making, glass making, chemical processes, ore refining, and steam for heating. 

Creep of Thick-walled Cylinders. The design of relatively thick-walled pressure vessels for operation at elevated temperatures where creep caimot be ignored is of interest to the oil, chemical, and power industries. In steam power plants, pressures of 35 MPa (5000 psi) and 650°C are used. Quart2 crystals are grown hydrothermaHy, using a batch process, in vessels operating at a temperature of 340—400°C and a pressure of 170 MPa (25,000 psi). In general, in the chemical industry creep is not a problem provided the wall temperature of vessels made of Ni—Cr—Mo steel is below 350°C. 

Chromium is the most effective addition to improve the resistance of steels to corrosion and oxidation at elevated temperatures, and the chromium—molybdenum steels are an important class of alloys for use in steam (qv) power plants, petroleum (qv) refineries, and chemical-process equipment. The chromium content in these steels varies from 0.5 to 10%. As a group, the low carbon chromium—molybdenum steels have similar creep—mpture strengths, regardless of the chromium content, but corrosion and oxidation resistance increase progressively with chromium content. 

Chemical-Process Vessels. Explosion-bonded products are used in the manufacture of process equipment for the chemical, petrochemical, and petroleum industries where the corrosion resistance of an expensive metal is combined with the strength and economy of another metal. AppHcations include explosion cladding of titanium tubesheet to Monel, hot fabrication of an explosion clad to form an elbow for pipes in nuclear power plants, and explosion cladding titanium and steel for use in a vessel intended for terephthaHc acid manufacture. 

The largest consumers of water in the United States are thermal power plants (eg, steam and nuclear power plants) and the iron and steel, pulp and paper, petroleum refining, and food-processing industries. They consume >60% of the total industrial water requirements (see also Power generation Wastes, industrial). 

Hydrauhc transport is used in mines and for lifting coals to the surface in Russia, Poland, and France. Pneumatic transport of coal is used over short distances in power plants and steel mills. The longest (14.5 km) single flight conveyer belt in the world near Uniontown, Kentucky, has a capacity of 1360 t/h. 

Three demonstrations of the LIMB technology have been carried out. The first was a privately funded project in the 75 MWt Boiler 405 at the No. 4 AC Station of Inland Steel Industries, Inc. (56). By injecting 70 wt % minus 200 mesh (74 -lm) limestone, approximately 40% SO2 removal was achieved at a Ca S ratio of 3. This rose to 50% removal when the Ca S ratio was increased to 4. The second LIMB demonstration was the backup desulfurization system installed by B W as part of the relocation, repowering, and reconfiguration of the PCS power plant (46). 

Data for determining the size of natural-draft towers have been presented by Chilton [Proc. Inst. Elec. Eng., 99,440 (1952)] and Rish and Steel (ASCE Swuposium on Thermal Power Plants, October 19.58). Chilton showed that the duty coefficient Df of a tower is approximately constant over its normal range of operation and is related to tower size by an efficiency factor or performance coefficient as follows ... 

FIG. 12-22 Universal performance chart for natural-draft cooling towers. (Risk and Steel, ASCE Symposium on Thermal Power Plants, October 1958. )... 

Another area of success has been in applied materials research. Because of the integral nature of materials to advances in energy production and consumption, the laboratories have developed a number of toughened ceramics. When used as a replacement for steel, they will improve the energy performance characteristics of high-temperature applications for components of combined-cycle power plants and vehicle engines. 

Table 1.29 tabulates most known examples of erosion corrosion problems occuring in aqueous systems. Historically, erosion corrosion first became a problem with the copper alloy (70%Cu 29%Zn l%Sn) condensers of naval shipsErosion corrosion of copper alloys has been an ongoing problem since then. The other major problem areas are (a) power plants where steels are exposed to water or water/steam mixtures in the temperature range 90°-280°C (b) the oil and gas industry where steels are exposed to various liquid, gas, and sometimes solids combinations containing carbon dioxide. 

Griskin et reported that there is no apparent effect of steam pressure on the rate of oxidation of Cr-Ni steels at temperatures between 600°C and 650°C at 10.1-20.2 MPa. Similar observations for Cr-Mo and Cr-Mo-V steels between 500°C and 600°C have been made by Wiles" . She compared low-alloy steel samples exposed to 101 kPa steam with power plant components that had operated for up to 150000b in steam at 17.25 MPa and found no significant difference in the oxidation rates (Fig. 7.11). 

Fig. 7.12 Influence of coal chlorine content on the furnace wall corrosion rates of mild steel tubes in low-pressure coal-fired power plant (Lees, C.E.G.B., private communication)...

Rohrig, van Duzer and Fellows exposed samples in an experimental superheater fed with steam at 2-6MN/m from a power plant. Some 42 materials were tested for periods of up to 16(XX)h, attack being estimated after test by weight loss following descaling. It was concluded that at 593°C attack continues at a high rate on carbon steel, whereas the rate for most alloy steels decreases with time (Table 7.10). 

C02 concentration in the flue gas from a combustion process varies from 4 tol4% in natural gas and coal-power plants, while other industries such as cement, iron and steel and petro-... 

Number 3 fuel oil (30° API) is transferred from a storage tank at 60°F to a feed tank in a power plant at a rate of 2000 bbl/day. Both tanks are open to the atmosphere, and they are connected by a pipeline containing 1200 ft equivalent length of 1 fin. sch 40 steel pipe and fittings. The level in the feed tank is 20 ft higher than that in the storage tank, and the transfer pump is 60% efficient. 

The element molybdenum (Mo) is found in all living organisms and is considered to be an essential or beneficial micronutrient. However, molybdenum poisoning of ruminants has been reported in at least 15 states and 8 foreign countries. Molybdenum is used primarily in the manufacture of steel alloys. Its residues tend to be elevated in plants and soils near molybdenum mining and reclamation sites, fossil-fuel power plants, and molybdenum disposal areas. Concentrations of molybdenum are usually lower in fish and wildlife than in terrestrial macrophytes. 

Stationary sources Waste incineration Steel industry Recycling plants Energy production Municipal solid waste, clinical waste, hazardous waste, sewage sludge Steel mills, sintering plants, hot-strip mills Non-ferrous metals (melting, foundry Al, Cu, Ptx, Zn, Sn) Fossil fuel power plants, wood combustion, landfill gas... 

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