Utilities, See Plant

Biodegradation. The biological mineralization of fixed nitrogen is well studied ammonia is oxidized to nitrite, and nitrite to nitrate, by autotrophic bacteria, and nitrate is reduced to nitrogen by anaerobic bacteria. Urea ia sewage and iadustrial wastes is readily hydrolyzed to ammonia and CO2 by many bacteria, and cyanides and cyanates are used as sole sources of carbon and nitrogen by some organisms. Wastewater treatment faciUties utilize these organisms ia assuting that municipal and iadustrial efflueats meet strict water quaUty standards, but this biological process is outside the scope of this article (see Water, industrial water treatment Water, municipal water treatment). On the other hand, ammonia and nitrate are essential nutrients for plant and bacterial growth, so one option is to use these organisms to take up and use the contaminants.  [c.36]

In late 1997, DSM (Stamicarbons parent company) will start up a new plant utilizing, the next step, a pool reactor (see Figs. 6 and 7). In 1999 this process should be offered for licensing.  [c.304]

Crop Rotation. Prior to about 1945, considerable dependence was placed on crop rotation as a means of supplying nitrogen. Certain plant varieties, particularly legumes such as peas and clovers, through a symbiotic relationship with certain sod bacteria, have the abdity to utilize atmospheric nitrogen for nutrition. Sod bacteria infect the roots of these plants, causing the development of characteristic nodules. At the sites of these nodules, by mechanisms that are quite compHcated, elemental atmospheric nitrogen becomes fixed and is absorbed into the root system of the plant (see Nitrogen fixation). In the farming system known as crop rotation, advantage is taken of this biological fixation by growing first a nitrogen-fixing legume, plowing it into the ground, and foUowing with growth of a nonlegume farm crop. This is an effective system, said to have been recognized even by the early Greeks. However, for modem high yield agriculture, it is inefficient. Alternate growing seasons are, to a large extent, lost by growing the legumes. Also, modern hybrid varieties of grains are voracious consumers of nitrogen, having requirements beyond the supply capabdity of a plowed-under legume crop.  [c.216]

The MCFC appears to be in the final stages of prototype testing, and a 234-ceU MCFC stack (0.37 m cell area, 70 kW) tested at ERC operates with a cross-flow gas distribution pattern (see Fig. 3). A 70-kW stack from ERC was also tested, starting in the fall of 1991, at a site of Pacific Gas and Electric Co. in San Ramon, California. In addition, ERC has tested a 120-kW, 244-ceU MCFC stack (0.56 m electrode area). The purpose of these tests was to demonstrate the feasibility of the technology for scaling up to large size MCFC stacks. A large demonstration plant utilizing the ERC technology in large fuel cell stacks (125 kW stacks, 0.56 m electrode area) to produce a 2-MW power plant in Santa Clara, California is expected to be operational by late 1994 or early 1995.  [c.583]

Energy reserves, production, and consumption in the world economy are given in Tables 11, 12, and 13, respectively. As these tables indicate, the overwhelming sources of petroleum reserves and supply are in the Middle East. Other significant sources of reserves include Russia, the North Sea, North American countries, and parts of southeast Asia. There are also significant concentrations of coal reserves in Russia and China. The dominant coal-producing countries include China and the United States, plus Poland, South Africa, AustraUa, India, Germany, and the United Kingdom. China is the single largest coal producer and consumer, utilizing over 22 EJ/yr (21 x 10 Btu/yr) of this soHd fossil fuel.  [c.6]

Hydrothemial processing encompasses a broad set of technologies which share a range of operating temperatures and pressures and require the use of engineered pressure systems. Table 1 compares the distinguishing features of these technologies, all of which utilize water heated to temperatures above its boiling point (nominally 100°C). These diverse technologies have common needs for equipment and plant design. Many of the designs can be translated from one appHcation to another (see also Highpressuretechnology).  [c.497]

Applications. AppHcations of radiometers and thermal imagers range from energy audits of buildings, to airborne crop surveys, to helping firefighters locate people in smoke-filled rooms. The appHcations related to chemical technology primarily deal with process monitoring and plant maintenance. Historically, many of these appHcations have been more fully utilized in other areas, particularly steel (qv) and electronics, but as engineered materials continue to replace metals and as quaHty control needs become more stringent, they are increasingly being adopted in chemical activities. The most obvious plant inspection tasks that radiometers and thermal imagers can be used for involve elevated or reduced temperature processes (see Temperature measurements). A thermal imager simplifies inspection because large areas can be surveyed rapidly and the image is normally much simpler to interpret than multiple point measurements. Abnormal temperature distributions in heat exchangers or air coolers can indicate blocked or constricted pipes. Leakage by a steam trap produces a local hot spot. Thermal inspection of furnaces can reveal poor flame patterns, inefficient combustion, and coking. The outer shells of insulated vessels inspected during operation show hot or cold spots wherever flaws occur in the refractory or insulating linings. The temperature determined at such a spot is a measure of the threat to the outer shell. A second group of appHcations involve detecting the heat produced by malfunctions or incipient failures. Worn bearings produce hot regions in mechanical equipment. Poor contacts in electrolytic ceUs are observable. Stressed transformers, breakers, and other electrical gear radiate at the stress points (81).  [c.204]

The Reactor. The nuclear power plant reactor types used to produce electricity worldwide are Hsted in Table 2 (see Nuclear reactors, reactor types). The lightwater reactor (LWR) is representative of commercial nuclear power plants. About 80% of the plants worldwide, and all of those in the United States, are LWR (1). The LWR uses ordinary or light water as distinguishable from heavy or deuterated water to transfer the heat generated from fission in the nuclear fuel assembhes, called the core, to make steam. The steam turns the turbine generators, which produce the electricity. Two versions of the LWR are utilized the two-circuit pressurized water reactor (PWR) in which the steam is made by circulating the heated water from the core into heat exchangers (or steam generators), which causes water in a second circuit to be brought to a boil to provide the steam, and the one-circuit boiling water reactor (BWR) in which the steam is generated in the core itself and goes direcdy to the turbine (8,14,32).  [c.239]

Normal Operation. The designer of a chemical plant must provide an adequate interface between the process and the operating employees. This is usually accompHshed by providing instmments to sense pressures, temperatures, flows, etc, and automatic or remote-operated valves to control the process and utility streams. Alarms and interlock systems provide warnings of process upsets and automatic shutdown for excessive deviations from the desired ranges of control, respectively. Periodic intermption of operations is necessary to ensure that instmments are properly caUbrated and that emergency devices would operate if needed (see Flow measurement Temperaturemeasurement).  [c.100]

The most modem smelters (ca 1997) use continuous smelting and converting processes which utilize high levels of oxygen-enriched air to produce a uniform flow of high strength process gas. This allows efficient acid plant design including high levels of energy recovery that was formerly only possible in sulfur-burning acid plants (see Metallurgy, extractive l tallurgy).  [c.184]

Tubulin Active Drugs. Vinblastin (48) and vincristin (49), two very useful natural products derived from Vinca rosea (periwinkle plant), were discovered in the early days of cancer chemotherapy (Table 5), (Fig. 6). (23). Vinblastin and vincristin ate highly cell cycle dependent. They dismpt the mitotic spindle by promoting the disassembly of the microtubules essential for cell division. This results in cell death during repHcation. Vinblastin and vincristin differ minimally from one another stmcturaHy, but have different clinical utilities. A search for additional members of the Vinca alkaloid family has resulted in two new investigational dmgs, vindesine (50) and navelbine (51) (24) (see Alkaloids), cuttendy undergoing clinical trial. Initial results using navelbine indicate that this compound may find use in nonsmaH cell lung cancer (25).  [c.440]

Chemurgy is defined as that branch of appHed chemistry devoted to industrial utilization of organic raw materials, especially from farm products. A more modem and general definition for chemurgy is the use of renewable resources particularly biomass, usually plant or microbial material, for materials and energy (see Fuels frombiomass Fuels fromwaste).  [c.448]

NSP s retrofit conversion is the electric utility iadustry s demonstration of the use of AFBC to repower an aging pulverized-coal furnace usiag a clean combustor, capable of burning fuel of lower quaUty. Pardy funded by the Electric Power Research Institute (EPRI), the 130 MWe FBC unit was constmcted ia 1985 by Foster Wheeler Energy Corp. The new unit is expected to provide a 25-year unit life extension and it has already reduced emissions per unit of electric power produced. Details of startup and equipment performance dufing the first eight months of operation are provided ia Reference 45. Another smaller retrofit project, ia which two bubbling-bed units were iastaHed ia 1990 by Energy Products of Idaho ia the 25 MWe Stream Plant No. 2 of Tacoma City Light, can bum coal, wood (qv), refuse-derived fuel (see Euels fromwaste), or a mixture of all three fuels ia a cost effective, efficient, and environmentally clean manner (43).  [c.260]

High Temperature Winkler Process. The high temperature Winkler (HTW) process developed by Rheinbraun is especially targeted for the gasification of brown and hard coals, peat, and biomasses in a fluidized-bed gasifier (19—25) (see Fuels frombiomass). The raw brown coal containing 50—60% moisture is dried down to 12% using Rheinbraun s drying process (19), which involves a fluidized-bed dryer using immersed heating surfaces for internal waste heat utilization. The vapor produced in this process is cleaned in an electrostatic precipitator that removes the fine coal particles and is then used either for fluidization or, after recompression, for drying the coal. The condensate serves to saturate the cleaned fuel gas before its entry into the gas turbine, thus further increasing the overall plant efficiency.  [c.270]

In 1985, owiag to the declining demand by the nuclear power industry for enriched uranium, the Oak Ridge gaseous diffusion plant was taken out of operation and, subsequently, was shut down. The U.S. gaseous diffusion plants at Portsmouth, Ohio and Paducah, Kentucky remain ia operation and have a separative capacity of 19.6 million SWU (separative work unit) per year which as of this writing is not fully utilized.  [c.87]

Energy management includes energy conservation, but also encompasses utility system rehabiUty the intermesh of process design with utility systems purchasing, including plant location for minimum energy cost environmental impacts of energy use tracking energy performance and the optimisa tion of energy against capital in equipment selection (see also Economic EVALUATION Power generation Process energy conservation).  [c.220]

Packed tower wet scrubbers to a certain degree are considered an outdated technology, although there are still many industrial operations that utilize them throughout the world. The greatest application for scrubbers from an environmental standpoint is likely flue gas scrubbing. Many systems are packaged designs offered by vendors. An example of a packaged system is illustrated in Figure 15. In this case the scrubber cleans 97-100% of the sulphuric dioxide (SO2, causing acid rain) and hydrochloric acid gases out of the flue gas, and also a high percentage of the dust. Since all the sulphur in the flue gas is removed, there are more options when selecting oil quality, as it becomes possible to bum waste oil and oils with a high sulphur content. The flue gas is cooled down towards 30 C making it possible to reduce the oil consumption by up to 20% when using the scrubber. The amount of savings depends on the plant s work efficiency throughout the year and on how effectively the low temperature heat is used. The scrubber is simple, but efficient a liquid flow meets the hot flue gas and particles, dust and water-soluble gases are washed out. The water is neutralized, cooled and reused. The water in the gas condenses when the hot gas meets the cold liquid. This process aids the removal of particles from the flue gas. In order to reduce the acidic content of the gas, lye is added to the water used in the scrubber. The salts formed can be released into the sea where they are found naturally. The scrubber is profitable for larger boiler houses for central heating, district heating, and for boilers of water or steam in industry. It is the oil consumption and the operating time, which determine the  [c.273]

For pipe sizes greater than 2 inches nominal, industry practice is to weld the pipe and fittings into one continuous system, and then use flanged or special bolted connections for attaching the valves, orifices, and connections to vessels or other equipment. For special lethal, high pressure, and steam power plant high tempera-ture/high pressure utility systems, even the valves and connections to vessels are welded into the system (See ASME and ANSI Codes). For these situations of about IJ -inch to 2-inch nominal pipe size and larger, use Figure 2-21 to determine the equivalent pipe lengths for these fittings, valves, etc. For example, a 45° welding elbow, or an open 6-inch gate valve (see line on chart) have an equivalent length of 6-inch pipe of four feet (straight), which is an addition to the actual straight pipe in the system. In  [c.86]

Due to the magnitude of the task of preparing such material in proper detail, it has been necessary to drop several important topics with which every designing engineer must be acquainted, such as corrosion, cost estimating, economics and several others. These are now left to the more specialized works of several fine authors. Recognizing this reduction in content. I m confident that in many petrochemical and chemical processes the designer will find design techniques adaptable to 75-80 percent of his/her requirements. Thus, an effort has been made to place this book in a position of utilization somewhere between a handbook and an applied teaching text. The present work is considered suitable for graduate courses in detailed process design, and particularly if a general course in plant design is available to fill in the broader factors associated with overall plant layout and planning. Also see Volumes 1 and 3 of this series.  [c.501]

Silver-based low-temperature brazing alloys have been known for many years and are widely employed throughout the engineering and chemical industries. Their output is measured in many tonnes per year, and their utility in joining almost all the commonly used materials of construction has made them indispensable for the production of a very wide range of plant, equipment and structures of all kinds. They exhibit a high resistance to corrosion by industrial atmospheres and possess excellent strengths at temperatures considerably higher than may be employed for lead or tin-based solders (see Section 10.5).  [c.937]

Instead of concentrating these functions ia one unit, it is also possible to create semispecific production trains, eg, for hydrogenations, phosgenizations, Friedel-Crafts alkylations (see Friedel-Crafts reactions), and Grignard reactions (see Grignard reaction). The choice between the iategrated and the satelHte plant design depends primarily on the degree of utilization of the various functions (1).  [c.438]

Another method, known as biaary technology, utilizes two fluids to convert hydrothermal energy to electricity. In such an operation, it is possible to extract the energy from hot water without any vaporization of the hydrothermal water. Figure 6 shows a schematic of a biaary plant. Heat from the geothermal water is transferred to a working fluid ia a heat exchanger. The working fluid is thereby vaporized and drives a generator. It is then recondensed and recirculated to be heated again by additional hydrothermal water. Typical working fluids are very volatile, low molecular weight hydrocarbons such as isobutane or fluoriaated hydrocarbons (see Heat-EXCHANGE technology,heat-TRANSFERMEDIA other thanwater). Biaary power geaerators are oftea only 1—2 MW ia capacity and ate usually employed as ganged units ia multimegawatt geothermal power statioas.  [c.266]

Eiae coal is not acceptable as Lurgi-type gasifier (Eig. 6) iaput. Power generation capacity of 240 MW was selected to utilize the fines produced duriag cmshing and handling of the coal. Oxygen (8600 t/d) is needed for the 36 Lurgi 4.0 m diameter gasifiers. High pressure steam requirements are 1230 t/h. Raw gas productionis about 1.65 x 10 m /h (1.4 x 10 ft /d). After quenchiag, this gas is fed to a Rectisol (cold methanol) purification plant to provide ca 1.2 X 10 m /h (1 X 10 ft /d) of pure gas (0.07 ppm S). The pure gas composition is about 1.5% CO2, 84.1% H2 + CO, 13.5% CH, 0.5% N2, and 0.4% C H. An adjacent oxygen plant consists of six units of 2300 t/d capacity, each at 3.45 MPa (500 psi). Steam generation iavolves six boilers produciag 540 t/h of 430°C, 4 MPa (580 psi) steam each. The Rectisol plant discharges H2S to a Claus unit which produces 99.97% pure sulfur (49) (see SULFURREMOVAL AND RECOVERY).  [c.159]

Production and Utilization. Unlike many newly discovered microbial polysaccharides, geUan has become a commercial success in a relatively short period. Discovered in the late 1970s, geUan was patented in 1982 (233,234). It was first marketed as a replacement for agar in microbiological apphcations under the trade name GELRITE (Kelco Division, Monsanto (formerly with Merck Co.)). The advantages of geUan over agar include higher purity, better clarity, and the abUity to obtain strong gels at lower polysaccharide concentrations. GeUan is especiaUy useful in marine microbiology, where agar-degrading microbes are often encountered. GeUan has also found biotechnological apphcations in plant tissue culture and in ceU immobilization (14,230). Another possible use is in air-freshener gels (16). In 1990 the U.S. EDA approved geUan for use as a food additive in icings, frostings, jams, jeUies, and fillings, where it can be used as a replacement for agar and carrageenans (235,236). Use of geUan as a general food additive for stabilizing, thickening, and gelling was approved by the EDA in 1992 (237). Additional apphcations include stmctured meat products, pet foods, candies, cheeses, yogurt, dressings, sauces, and ice cream and other frozen desserts (13,238) (see Eood additives Meatproducts Milkandmilkproducts).  [c.299]

As of 1995, the cost for fuel ceU-based power plants was prohibitive when compared to conventional options. This cost may come down ia the latter 1990s if manufacturers of these devices receive enough orders to achieve economies of scale. Fuel cells have many potential advantages compared to conventional power cycles. For example, fuel cells generate very Httie pollution either ia emissions or noise. Thus these cells are ideal for siting ia populated areas close to loads where it may be difficult to site conventional power sources because of permitting issues. In addition, small fuel cell power plants can potentially mn as unstaffed faciUties. FiaaHy, fuel cells do generate significant levels of waste heat that can be captured and utilized to improve overall plant efficiency (see Process energy conservation).  [c.18]

Production of carbon disulfide expanded rapidly after World War II to supply the growing needs of the viscose rayon industry, which consumes about 0.31 ton CS2 per ton rayon. The high plant capacities obtainable with the methane—sulfur route resulted in consoHdation of the carbon disulfide industries in the United States and Western Europe, where a few producers now account for the bulk of the capacity (see Table 3). Some rayon manufacturers produce their own carbon disulfide. Rayon enjoys an extensive international market that can affect local CS2 manufacturers. Competition from nonceUulosic synthetic fibers has caused a drop in rayon production in the United States since the mid-1960s. One rayon plant in the United States closed in 1989 as a result of environmental concerns. However, plans have been announced to build a new rayon plant in Louisiana (130) that is expected to achieve improved carbon disulfide utilization and low emissions by recovering and recycling carbon disulfide. This pattern of modem viscose rayon plants replacing aging faciUties that cannot be economically upgraded is apt to be repeated in other parts of the world. In a development that could have far-ranging implications, a viscose rayon producer is constmcting a solvent spun ceUulosic fiber plant using an amine oxide solvent rather than carbon disulfide (131,132).  [c.32]

Dry-Process Kilns, Suspension Preheaters, and Precalciners. The dry process for cement manufacture utilizes a dry kiln feed rather than a slurry. Early dry-process kilns were short, and the substantial quantities of waste heat ia the exit gases from such kilns were frequentiy used ia boilers for electric power generation (qv) the power generated was frequentiy sufficient for all electrical needs of the plant. In one modification, the kiln has been lengthened and chains have been added however, these serve almost exclusively a heat-exchange function (see Heatexchangetechnology). Refractory heat-recuperative devices, such as crosses, lifters, and trefoils, have also been iastaHed so that the long dry kiln is energy efficient. Other than the need for evaporation of water, its operation is similar to that of a long wet kiln.  [c.293]

In statistical analyses of the copper, brass, and bronze industry (7), there are five primary markets (/) budding constmction (41%), including budding wiring, plumbing, and heating air conditioning (qv) and commercial refrigeration (see Refrigeration) budders hardware, and architectural materials (see Building materials, survey) (2) electrical and electronic products (23%), for example, power utilities, telecommunications, business electronics, and lighting and wiring devices (see also Electrical connectors Electronic materials) (i) industrial machinery and equipment (14%), such as in-plant equipment, industrial valves and fittings, nonelectrical instmments, off-highway vehicles, and heat exchangers (see Heat exchange technology) (4) transportation (qv) equipment (12%), including automobdes, tmcks and buses, radroads, marine vehicles, aircraft, and aerospace vehicles and (5) consumer and general products (10%), such as apptiances, cord sets, ordnance, consumer electronics, fasteners, coinage, utensds and cutlery, and miscellaneous items.  [c.212]

Natural Circulation Evaporators. Natural ckculation evaporators (Fig. 1) were the first developed commercially and stiU represent probably the largest number of units in operation. These evaporators utilize the density difference between the Hquid and the generated vapor to circulate the Hquid past the heating surface and thereby give good heat-transfer performance. The heat transfer tubes may be either vertical or horizontal, with the Hquor either inside or outside the tubes. The horizontal tube type of Figure la has the heating steam inside the tubes that are immersed in the boiling Hquid. This type was originally built with rectangular cast-iron bodies having a hemicylindrical top that required Httie floor space or headroom. The principal use is for making distilled water for boiler feed. These evaporators are incorporated in the power plant cycle, usually as single effects heated by turbine bleed steam and exhausting vapor to the feed heater circuit (see Power generation). They frequendy operate under considerable pressure, and therefore employ horizontal cylindrical sheUs to better withstand the pressures and give a large Hquid surface area for efficient disengagement. The type shown in Figure lb was developed mainly for use in sugar mills, and was known as the standard evaporator now it is known as the calandria or short-tube vertical (STV) evaporator. It employs fairly large (usually 0.05-m) diameter tubes only about 2 m long that are easily cleaned mechanically. Good heat transfer requites downtakes to permit recitculation through the tubes. The downtakes must have a flow area on the order of 60% or more of the flow area through the tubes themselves. The use of large-diameter short tubes and the need for a large downtake area result in a large body diameter relative to the amount of heating surface provided, usually larger than would be needed for vapor—Hquid disengagement alone.  [c.472]

The human race has now interfered with the environment of its planet to an extent that global environmental catastrophes are a possible consequence. Foremost in the mind of many is the problem of global warming which, if it occurred as rapidly as seems possible, the resultant climatic change, local weather modifications and rises in sea level would overwhelm the institutional capabilities of society to manage change. Other potential environmental catastrophes may be more subtle, however, and the issue of endocrine disrupting chemicals might ultimately prove to be of that kind. It has now been known for more than a decade that some widely used chemicals, when dispersed within the environment, cause changes to the sexual development of exposed organisms. The most acute of these problems, such as that caused by the use of TBTO anti-fouling paint, are fairly well defined and are controllable. What is more worrying is that low level exposure to a wide range of chemicals may be affecting endocrine function, leading to serious outcomes such as reduced fertility and increased reproductive cancers. Some of the chemicals implicated are extremely long-lived, and the ultimate nightmare would be a discovery that contemporary concentrations of an extremely persistent substance could lead to such problems for a large proportion of the global population. At present the evidence to substantiate such fears is weak, but the current level of knowledge is poor and it is unclear what as yet unrecognized problems may arise in the next few years. The endocrine disrupting chemicals issue is undoubtedly a very important one and should be a major concern for all of those producing, distributing or utilizing chemicals in any form.  [c.155]

See pages that mention the term Utilities, See Plant : [c.380]    [c.105]   
Hazardous chemicals handbook Изд.2 (2002) -- [ c.0 ]