Utilities refrigeration


Utilities are varied. The most common hot utility is steam. It is usually available at several levels. High-temperature heating duties require furnace flue gas or a hot oil circuit. Cold utilities might be refrigeration, cooling water, air cooling, furnace air preheating, boiler feedwater preheating, or even steam generation at higher temperatures.  [c.185]

A refrigeration system is a heat pump in which heat is absorbed below ambient temperature. Thus the appropriate placement principle for heat pumps applies in exactly the same way as for refrigeration cycles. The appropriate placement for refrigeration cycles is that they also should be across the pinch. As with heat pumps, refrigeration cycles also can be appropriately placed across utility pinches. It is common for refrigeration cycles to be placed across a utility pinch caused by maximizing cooling water duty.  [c.206]

Wkiterization is a specialized appHcation of fractional crystallization that is utilized to remove saturates or waxes from Hquid oils. Salad oils, which do not cloud at refrigerator temperature, have been produced by winterizing lightly hydrogenated soybean ok. However, many producers now use refined, bleached, deodorized oks for this purpose (24).  [c.127]

The reason for the popularity of anhydrous ammonia is its economy. No further processing is needed and it has a very high (82.2%) nitrogen content. Additionally if held under pressure or refrigerated, ammonia is a Hquid. Being a Hquid, pipeline transport is practical and economical. A network of overland pipelines (Fig. 4) is in operation in the United States to move anhydrous ammonia economically from points of production near natural gas sources to points of utilization in farming areas (see Pipelines).  [c.217]

In all HF processes, the HF leaves the furnace as a gas, contaminated with small amounts of impurities such as water, sulfuric acid, SO2, or SiF. Various manufacturers utilize different gas handling operations, which generally include scmbbing and cooling. Cmde HF is condensed with refrigerant, and is further purified by distillation (qv). Plant vent gases are scmbbed with the incoming sulfuric acid stream to remove the bulk of the HF. The sulfuric acid is then fed to the furnace. Water or alkah scmbbers remove the remainder of the HF from the plant vent stream.  [c.196]

Dehydration may also be accompHshed by expansion refrigeration which utilizes the Joule-Thompson effect. This technique is normally used when the prime objective is hydrocarbon recovery.  [c.171]

Thermal Engine Cycles. Thermal engine cycles operating with organic refrigerants are employed to recover energy from waste heat streams at temperatures below 150°C. Recovery of such heat is justified only when recovery caimot be effected through process-oriented heat utilization. Typical systems employ the Rankine cycle to produce electrical or shaft power. Thermal efficiencies of Rankine cycles are low, but thermal engines are appHed when large quantities of waste heat are available. The most frequently used refrigerants are halocarbons and hydrocarbons. Mixed refrigerants that evaporate and condense over a selected temperature range are used when the available heat source undergoes a wide temperature change as heat is removed. Cascaded systems, ie, thermal engine cycles in series operating at different temperatures, sometimes are employed to increase thermal efficiencies. In such systems, each thermal engine cycle may employ a different refrigerant.  [c.509]

A low temperature of approach for the network reduces utihties but raises heat-transfer area requirements. Research has shown that for most of the pubhshed problems, utility costs are normally more important than annualized capital costs. For this reason, AI is chosen eady in the network design as part of the first tier of the solution. The temperature of approach, AI, for the network is not necessarily the same as the minimum temperature of approach, AT that should be used for individual exchangers. This difference is significant for industrial problems in which multiple shells may be necessary to exchange the heat requited for a given match (5). The economic choice for AT depends on whether the process environment is heater- or refrigeration-dependent and on the shape of the composite curves, ie, whether approximately parallel or severely pinched. In cmde-oil units, the range of AI is usually 10—20°C. By definition, AT A AT. The best relative value of these temperature differences depends on the particular problem under study.  [c.521]

Bulk quantities of helium and argon and smaller quantities of neon are distributed as cryogenic Hquids in insulated containers of Hquid capacities of 10—56,000 L (2.5—14,800 gal). Although the cryogenic refrigeration of the Hquid is sometimes utilized as for magnetic resonance imaging (MRI), another justification for this mode of distribution is the lower transportation costs resulting from reduced ratios of shipping container weight to product weight (see Imaging technology). This factor is particularly important for such a low density material as helium. For example (85), the weight of compressed-gas cylinders is about 45 times that of their helium content on the other hand, the weight of a 500-L cryogenic Hquid container is only about eight times the weight of the helium, and large Hquid—heHum semitrailers are only about four times heavier than their helium load.  [c.12]

Utilities. Electricity, water, steam refrigeration, and compressed air must be provided to the pasteurizer for heating, cooling, and cleaning of water. The water is heated by steam injection or an enclosed heating and circulating unit. The controller, sensing the hot water temperature, permits heating until the preset temperature is reached, usually 1—2°C above the pasteurization temperature. A diaphragm valve, directed by the controUer, maintains the maximum temperature of the hot water by control of the steam. Water is cooled with a direct expansion refrigeration system and may be cooled directiy or over an ice bank formed by direct expansion refrigeration. The compressed air should be clean, relatively dry, and suppHed at - ISS kPa (20 psi) to operate valves and controls.  [c.359]

Pipeline systems for transporting anhydrous ammonia that are urea and ammonium nitrate (UAN) and LNG compatible, exist in Europe, Mexico, and the Soviet Union. Export-oriented ammonia producing countries utilize huge ocean-going tankers that contain up to 50,000 t for distribution of ammonia. Co-shipment in refrigerated LNG tankers is usuaky done.  [c.354]

Absorption chiller units (Fig. 13) need 1.6—1.8 J (0.38—0.43 cal) of waste heat per joule (0.24 cal) of refrigeration. Commercially available LiBr absorption units are suitable for refrigeration down to 4.5°C. For low level waste heat (90—120°C), absorption chillers utilize waste heat as efficientiy as steam turbines using mechanical refrigeration units. Absorption refrigeration using 120°C saturated steam deUvers 4.5°C refrigeration, having an efficiency, with respect to the work potential in the steam of 35%.  [c.92]

Compressors used in a typical refrigerator/freezer are of the positive displacement type, utilizing either reciprocating or rotary motion (Eig. 5) and  [c.62]

To satisfy these conditions, the cascade cycle is utilized (Fig. 8). This consists of two or more separate refrigeration cycles. The cascade condenser-evaporator rejects heat to the evaporator of the high temperature cycle, which condenses the refrigerant of the low temperature cycle. This makes possible the use of refrigerant such as R-13 (see Table 1) in the low stage, with pressure—temperature—volume (P—T—V) characteristics suited to low temperature. Refrigerants with P—T—V characteristics more favorable at higher temperatures, ie, R-12 or R-22, are used in one or more higher stages. For extremely low temperatures, more than two refrigerants maybe cascaded as, for example, methane—ethylene—propane is to produce — 160°C evaporator temperatures. Expansion tanks, sized to handle the low temperature refrigerant as a gas at ambient temperatures, are used during standby to hold pressures at levels suitable for economical equipment design.  [c.66]

Chemical Leavening. Chemical Haveners (primarily baking powders) are utilized in cakes, cookies, some crackers, refrigerated dough, and quick bread manufacturing (9—12). These products make up roughly 39% of the value of the baking industry s total production (see Bakery processes and LEAVENING AGENTS, CHEMICAL LEAVENING AGENTs). Both yeast and chemical Haveners are occasionally used together in the same formulation, for example in the production of certain frozen doughs.  [c.460]

Yeast. Most of the yeast (6,18,19) used by wholesale bakers is available in the form of fresh compressed yeast, granular, or as cream yeast (a slurry). Fresh or creamed yeasts are deflvered at frequent intervals and refrigerated until used. Yeast fermentation leads to gas production which, in turn, leads to leavened dough and bread as well as the development of fermentation flavors. The quantity of yeast added to dough is directly related to the time required for fermentation. Currently, most bread doughs are made with 2 —3% fresh compressed yeast, based on flour. This amount varies depending on the form of yeast utilized. High sugar levels in sweet yeast-raised doughs tend to inhibit yeast activity through increased osmotic pressure and higher yeast levels are necessary to compensate.  [c.461]

Refrigeration for cryogenic appHcations is produced by absorbing or extracting heat at low temperatures and rejecting it to the atmosphere at higher temperatures. Three general methods for producing cryogenic refrigeration in large-scale commercial appHcations are the Hquid vaporization cycle, the Joule-Thomson (J-T) expansion cycle, and the engine expansion cycle. The first two are similar in that they both utilize irreversible isenthalpic expansion of a fluid, usually through a valve. Expansion in an engine approaches reversible isentropic expansion with the performance of work.  [c.326]

The multicomponent (mixed) refrigerant cycle utilizes J-T refrigeration from a mixture including nitrogen and a blend of hydrocarbons from methane to butane or pentane. This cycle has a simplified arrangement compared to the other cycles. The mixture composition is optimized to obtain close temperature approaches to the condensing feed gas, and reduce the power for LNG production. The mixture is compressed to about 3 MPa (435 psi), partially condensed against cooling water, precooled, condensed, and subcooled in a heat exchanger, then reduced in pressure across a J-T valve to about  [c.328]

Except for neon, there are no gases boiling between nitrogen and hydrogen, so cascading of refrigeration by condensing one fluid against another boiling at above ambient pressure is not feasible. Consequentiy, refrigeration below 77 K is provided by expanders, or by vacuum nitrogen (triple point 63.2 K) in combination with expanders. A cycle utilizing only hydrogen expanders for refrigeration (no Hquid nitrogen precooling) is shown in Figure 6 (14—15).  [c.330]

Utilities These include steam, cooling water, process water, electricity, fuel, compressed air, and refrigeration. The consumption of utilities can be estimated from the material and energy balances for the process, together with the equipment flow sheet.  [c.855]

Utilities and yard services (boiler plant, refrigeration, compressed air, water supply and treatment, effluents, fire protection, yard piping, yard electrical, yard materials handling, raw and finished-product storage)  [c.864]

T Utility equipment (boilers, generators, refrigeration)  [c.864]

Ammonia refrigeration plants are almost exclusively built as recirculating systems. The main advantage of recirculating versus direct expansion systems is better utilization of evaporator surface area. The diagram showing influence of quality on the local heat-transfer coefficients is shown in figure 11-90. It is clear that heat-transfer characteristics will be better if the outlet quahty is lower than 1. Circulation could be achieved either by pumping (mechanical or gas) or using gravity (thermosyphon effect density of pure liquid at the evaporator entrance is higher than density of the vapor-liquid mixture leaving the evaporator). The circulation ratio (ratio of actual mass flow rate to the evaporated mass flow rate) is higher than 1 and up to 5. Higher values are not recommended due to a small increase in heat-transfer rate for a significant increase in pumping costs.  [c.1108]

Heat supplied to the generator is boihng weak (dilute) absorbent solution on the outside of the tubes. Evaporated water is condensed on the outside of the condenser tubes. Water utilized to cool the condenser is usually cooled in the coohng tower. Both condenser and generator are located in the same vessel, being at the absolute pressure of about 6 kPa. The water condensate passes through a hquid trap and enters the evaporator. Refrigerant (water) boils on the evaporator tubes and cools the water flow that brings the refrigeration load.  [c.1118]

FIG. 11-113 Claude cycle refrigerator utilizing both expansion processes.  [c.1129]

Ross, I. and Robinson, T., Offshore Gas Conservation Utilizing a Turboexpander Based Refrigeration Extraetion Cyele, Offshore Europe Conferenee, September 1981.  [c.83]

Direct expansion is also possible wherein the refrigerant is used to chill the incoming air directly without the chilled water circuit. Ammonia, which is an excellent refrigerant, is used in this sort of application. Special alarm systems would have to be utilized to detect the loss of the refrigerant into the combustion air and to shut down and evacuate the refrigeration system.  [c.99]

The total plant or train main process bottleneck will probably be identified by the licensor, such as the gasifier for a coal gasification train, the main exchanger for a mixed refrigerant LNG plant train, or the cracked gas compressors for an olefin plant. First and foremost, be sure that the licensor has not made the utility area a bottleneck. This can never be allowed since overloaded utilities could repeatedly shut the entire complex down on a crash basis, adversely impacting economics.  [c.221]

The compressors to be covered in this book are those using mechanical motion to effect the compression. These types of compressors are commonly used in the process and gas transport/distribution industries. A partial list of these industries includes chemical, petrochemical, refinery, pulp and paper, and utilities. A few typical applications are air separation, vapor extraction, refrigeration, steam recompression, process and plant air.  [c.1]

The applieation of aetivated earbons in adsorption heat pumps and refrigerators is diseussed in Chapter 10. Sueh arrangements offer the potential for inereased efficiency because they utilize a primary fuel source for heat, rather than use electrieity, which must first be generated and transmitted to a device to provide mechanical energy. The basic adsorption cycle is analyzed and reviewed, and the ehoiee of refrigerant-adsorbent pairs discussed. Potential improvements in eost effeetiveness are detailed, including the use of improved adsorbent carbons, advanced cycles, and improved heat transfer in the granular adsorbent earbon beds.  [c.557]

Failure of eoolant, refrigerant, or other utilities.  [c.257]

Good temperature control of the plastic and pressure control ahead of the coating die is important to the success of the coating. Variations in temperature lead to irregularities in the coating thickness both in the machine direction and across the web. Variations in the cross-web direction can be reduced by adjusting the slot opening via the adjusting bolts. The extmded film width is adjustable by external deckles to block off the exit of the die. In the laminator the nip helps to promote bonding, before chilling the molten plastic. The driven chill roU is chromium or nickel plated and can have a mirror, matte, or an embossed surface. Once the extmded film passes through the laminating nip, it takes on the finish of the chill roU. The chill roU is 60—90 cm in diameter and utilizes refrigerated water to reduce the film temperature to ca 65°C in the 120° wrap of the chill roU before the film is stripped. To improve adhesion of the extmded film to the substrate, adhesion-promoting primers are usually appHed to the web before the laminator. Priming can be electrostatic, chemical, or in the form of ozone treatment. Coating weights are controlled by the line and extmder speeds. However, in many cases the chill roU capacity limits the maximum thickness to be obtained.  [c.311]

Anhydrous ammonia is a gas at ambient temperatures and pressure, which dictates special procedures for storage, handling, and field appHcation. Both pressure storage and refrigerated storage are utilized to maintain ammonia ia Hquid form. For large storage depots, the preference usually is for refrigerated storage ia large, weU-iasulated vessels at or near atmospheric pressure. The vapor pressure of anhydrous ammonia is such that refrigeration to about —33°C is required to avoid boiling at atmospheric pressure. In the iasulated storage vessels, this refrigeration is accompHshed simply by aHowiag the ammonia to boil ia amounts equivalent to the ia-leakage of heat, and providing compressor and condenser capacity for reHquification of the vapor. Smaller storage depots sometimes use semirefrigerated storage, ie, storage at somewhat elevated pressure but with compressor capacity for some recondensation. The advantage over storage at atmospheric pressure is that a higher storage temperature can be used, with resultant lowered refrigeration requirement (see Refrigeration).  [c.218]

Hydrogen-storage alloys (18,19) are commercially available from several companies in the United States, Japan, and Europe. A commercial use has been developed in rechargeable nickel—metal hydride batteries which are superior to nickel—cadmium batteries by virtue of improved capacity and elimination of the toxic metal cadmium (see BATTERIES, SECONDARYCELLS-ALKALINe). Other uses are expected to develop in nonpolluting internal combustion engines and fuel cells (qv), heat pumps and refrigerators, and electric utility peak-load shaving.  [c.300]

Types of Separations. The first type of adsorption separation is based on differences in the size and shape of molecules (1,23). The molecular sieve separation of hydrocarbons by zeoHte calcium A (5 A) is used in commercial processes for the recovery of normal paraffins from hydrocarbon feedstocks (27) (see Adsorption, liquid separation). Paraffin isomers and cycHc hydrocarbons are too large to be adsorbed and are excluded. The recovered / -paraffins are utilized, for example, in the manufacture of biodegradable detergents. The affinity of zeoHtes for water and other polar molecules, decreases with rising Si02/AI2O2. Therefore, low siUca zeoHtes can be used for drying gases and Hquids. However, in many instances, secondary reactions such as polymerization of a coadsorbed olefin may take place. This is avoided by using the potassium-exchanged form of zeoHte A (3A) for the removal of water from unsaturated hydrocarbon streams. The effective pore size of 3A excludes all hydrocarbons, including ethene. The molecular-sieve effect for water removal is also utilized in the drying of refrigerants. In this instance, zeoHte A (4A) is employed because the size of the refrigerant molecules, such as refrigerant-12 with a kinetic diameter of 0.44 nm, is too large to be adsorbed. The second type of adsorption separation is based on differences in the relative selectivity of two or more coadsorbed gases or vapors. An outstanding example of this type is the production of oxygen-enriched air by the selective adsorption of nitrogen at ambient temperature on various molecular-sieve zeoHtes, including calcium A, calcium X, and various types of mordenite. Many separations based on relative selectivity range from simple drying processes to the separation of sulfur compounds from natural gas, and of aromatics from saturated hydrocarbons.  [c.449]

Polypropylene can be molded into an integral hinge that can be flexed repeatedly without failure. This property is frequently utilized in the design of container closures, lunchboxes, and similar articles. Polypropylene closures are used on a wide variety of containers, including child-proof caps and screw caps on plastic beverage bottles. Medical devices injection molded from polypropylene include syringes, pans, trays, and a variety of utensils. A large variety of toys, cups, dishes, and other household articles are molded from polypropylene. The development of high melt flow rate copolymer grades for thin-waH injection mol ding (159) has increased the use of polypropylene in food containers. Random copolymers are used in containers when high clarity is desired the impact properties of these polymers are acceptable at refrigerator temperatures, but impact modification is required for some freezer appHcations. Filled compositions and the newer high stiffness grades provide the stiffness and high temperature properties desired in dishwashers and other appHances (160). Molded outdoor furniture is also frequently produced with mineral-filled polypropylene.  [c.421]

The Guggenheim process was developed to permit the treatment of low grade caUche ores, making it possible to mine by mechanical methods instead of by hand. Furthermore, this lower grade ore could be leached with only slightly warm solutions, as opposed to the boiling solutions requited for high grade ore, and the nitrate was precipitated by refrigeration, replacing the process of evaporation and cooling in open tanks. In order to provide low cost heat to warm the leach solutions and make subsequent mechanical refrigeration economical, a carefully balanced system of power-plant heat recovery was put into operation (5). The utilization of the Guggenheim process has made it possible commercially to exploit reserves having as low as 7%) NaNO ore. The process used in the mid-1990s is basically the same as the original one. Only a few modifications had been made, eg, those that permit obtaining anhydrous sodium sulfate and iodine as by-products.  [c.193]

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]

Magnetic resonance imaging (MRI) uses cryogenics to cool high conductivity magnets for nonintmsive body diagnostics. Low temperature infrared detectors are utilized in astronomical telescopes. Cryogenic technology is being used to increase the speed of computers. Cryogenic refrigerators have been appHed industrially for cryopumping to yield high pumping speeds and ultrahigh vacuum. With the recent advent of high temperature superconductivity, it is anticipated that appHcations of superconductivity at near Hquid nitrogen temperature have great potential for electric power transmission, magnetic transportation systems, and magnets for energy generation in fusion processes.  [c.326]

Base/oadUSIGp/antsh.a.ve predominandy used variations of the mixed refrigerant cycle, although some have utilized the cascade cycle. The mixed refrigerant cycle can be precooled by a high stage cycle that may be a propane refrigerator, a second separate mixed refrigerant cycle, or even an ammonia absorption system (8—11). The propane precooled mixed refrigerant cycle shown in Figure 3 has low energy requirements, characteristic of the cascade cycle, but a simpler equipment arrangement. Baseload plants generally recover propane and heavier components from the natural gas for internal use in charging the refrigeration systems, or for external use as LPG, butane, or natural gasoline. Baseload LNG plants range in size from about 3 to 10 million STP m per day LNG production. Machinery for the baseload plants is centrifugal or axial compressors driven by steam or gas turbines. Baseload LNG plants serve the trade to Japan, Taiwan, and Korea from Alaska, Malaysia, Borneo, Indonesia, Australia, and the Persian Gulf, as well as trade from North Africa to Europe and the United States.  [c.329]

Predemethanization. The conventional design employs a single-step multiple feed tower. Utilization of a second tower upstream of the existing primary tower reduces the load on the primary tower. This reduces the propylene refrigeration power and reduces the propylene chilling loads. This approach is typically uneconomical with low pressure demethanizers, but has been combined with high pressure demethanizer systems by some Hcensors.  [c.442]

The most common types of water-cooled refrigerant condensers are (1) shell-and-tube, (2) shell-and-coil, (3) tube-in-tube, and (4) brazed-plate. Shell-and-tube condensers are built up to 30 MW capacity. Cooling water flows through the tubes in a single or multipass circuit. Fixed-tube sheet and straight-tube construction are common. Horizontal layout is typical, but sometimes vertical is used. Heat-transfer coefficients for the vertical types are lower due to poor condensate drainage, but less water of lower purity can be utilized. Condensation always occurs on the tubes, aud often the lower portion of the shell is used as a receiver. In shell-and-coil condensers water circulates through one or more continuous or assembled coils contained within the shell while refrigerant condenses outside. The tubes cannot be mechanically cleaned nor replaced. Tube-in-tube condensers could be found in versions where condensation occurs either in the inner tube or in the annulus. Condensing coefficients are more difficult to predic t, especially in the cases where tubes are formed in spiral. Mechanical cleaning is more comphcated, sometimes impossible, and tubes are not replaceable. Brazed-plate condensers are constructed of plates brazed together to make up an assembly of separate channels. The plates are typically stainless steel, wave-style corrugated, enabhng high neat-transfer rates. Performance calculation is difficult, with very few correlations available. The main advantage is the highest performance/volume (mass) ratio and the lowest refrigerant charge. The last mentioned advantage seems to be the most important feature for many apphcations where minimization of charge inventoiy is crucial.  [c.1113]

Freezing as a means of preseivdng food dates back to 1840. However, today the food industiy uses large quantities of hquid nitrogen for this purpose and as a refrigerant in frozen-food transport systems. In biologic apphcations hquid-nitrogen cooled containers are routinely used to presei ve whole blood, tissue, bone marrow, and animal semen for extended periods of time. Cryogenic surgery has become accepted in curing such involuntaiy disorders as Parkinsons disease. Medical analysis of patients has increased in sophistication with the use of magnetic resonance imaging (MRl) which utilizes ciyogenically cooled superconducting magnets. FinaUy, one must recognize the role that ciyogenics plays in the chemical-processing industry with the recoveiy of valuable feedstocks from natural gas streams, upgrading the heat content of fuel gas, purification of various process and waste streams, the production of ethylene, and so on.  [c.1126]

The utilities in our modern society are so much a part of our lives that it is hard to imagine how we survived without them. An electric power plant generates electricity to heat and light our homes in addition to providing power for the television, refrigerator, and electric toothbrush. When our homes were heated with wood fires, home-made candles were used  [c.75]

Non-azeotropic mixtures have been utilized in refrigeration systems for several direct and indirect advantages like, enhanced coefficient of performance, lower power consumption, reduced thermal irreversibility, increased chemical stability, improved oil miscibility, varying condensation temperatures and variable capacity refrigeration systems. All these merits offer rich prospects for the use of mixed component working fluids in heat pumps, power cycles and refrigeration systems. In the mid 1980s, a new thermodynamic power cycle using a multicomponent  [c.52]


See pages that mention the term Utilities refrigeration : [c.525]    [c.85]    [c.1128]    [c.1407]   
Health, safety and accident management in the chemical process industries (2002) -- [ c.157 ]