After-Coolers

Inter-coolers Coolers are primarily used to reduce the operating temperature within a compressor circuit, which allows the use of a smaller machine with fewer cylinders. These coolers may vary in size and type (e.g., shell and tube, air coolers, and U-tube) and 

Operation—The plant operations personnel need room to walk safely around the machine. They must have access to valves, switches, and gauges and must be able to see all gauges, lights, and dials on the control panels. 

Maintenance—All principal components to be removed during major maintenance must be able to be lifted by the traveling crane, swung laterally to the clear area (designated in Exhibit 4-33), and removed from the building. 

Climate conditions—Installation in temperate climates may require only a roof that provides limited 5roteaion from the elements. In warmer climates, a nirtain wall struaure may be the right application, A turtain wall has a complete roof and four sides that ire open from the operating level to a height of 8 ft 2,400 mm). The roof blocks the sun for most of the 

EXHIBIT 4-42 CentriAigai Compressor with Inter-Cooler and Piping Between Stages 

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Applications Two principal applications are rotating equipment oil coolers and compressor inter- and after-coolers. Although seemingly different applications, both rely on the shellside finning to enhance the heat transfer of low heat-transfer characteristic fluids. 

This standard could be adapted to the fuel compressor for the natural gas to be brought up to the injection pressure required for the gas turbine. Covers the minimum requirements for reciprocating compressors and their drivers used in petroleum, chemical, and gas industry services for handling process air or gas with either lubricated or nonlubricated cylinders. Compressors covered by this standard are of moderate-to-low speed and in critical services. The nonlubricated cylinder types of compressors are used for injecting fuel in gas turbines at the high pressure needed. Also covered are related lubricating systems, controls, instrumentation, intercoolers, after-coolers, pulsation suppression devices, and other auxiliary equipment. 

Common TEMA designations are AET and BET, and typical applications include exchangers handling chemical fluids, hydrocarbon fluid condensers, air or gas compressors, and inter-and after-coolers. 

X - HEAT EXCHANGER RB - REBOILER 1C - INTERCOOLED COMPRESOR AC- AFTER COOLER... 

A - ABSORBER FD - FLASH DRUMS C - COMPRESSORS 1C - INTERCOOLED COMPRESSORS P- PUMP T - HYDRAULIC TURBINE D - DEHYDRATOR AC - AFTER COOLERS X- THROTTLE G GENERATOR... 

Uses ten times the oil of a reciprocating. Usually install after-cooler and separator to recycle oil. 

Screw compressors are rotary positive displacement machines. Two helical rotors are rotated by a senes of timing gears as shown in Figure 10-8 so that gas trapped in the space between them is transported from the suction to the discharge piping. In low-pressure air service, non-lubri-cated screw compressors can deliver a clean, oil-free air. In hydrocarbon service most screw compressors require that liquid be injected to help provide a seal. After-coolers and separators are required to separate the seal oil and recirculate it to suction. 

The temperature at the exit of the compressor is cooled with an adjustable cooling system called an aftercooler. Such a system is useful in adjusting the output air for specific application purposes. The after cooling process is assumed to be a constant pressure process. The volumetric flowrate from the fourth stage is (cfm), then the volumetric flowrate after the flow or passed through the after cooler q (cfm) will be... 

The main components of the GM-type PTR are shown in Fig. 5.21(b). From the left to the right, the pulse tube system consists of a compressor (CP), a room temperature heat exchanger or an after-cooler (E,), a rotary valve (RV), a regenerator (RG), a low-temperature heat exchanger (Ej), a pulse tube (PT), another room temperature heat exchanger (E3), two orifices (C and 02) and a buffer volume (BF). 

Several large accidents have been caused by flammable vapors being sucked into the intake of air compressors subsequent compression resulted in autoignition. A compressor is particularly susceptible to autoignition if it has a fouled after-cooler. Safeguards must be included in the process design to prevent undesirable fires that can result from adiabatic compression. 

The principles of fluidisation, discussed in Chapter 6, are applied in this type of dryer, shown typically in Figure 16.25. Heated air, or hot gas from a burner, is passed by way of a plenum chamber and a diffuser plate, fitted with suitable nozzles to prevent any back-flow of solids, into the fluidised bed of material, from which it passes to a dust separator. Wet material is fed continuously into the bed through a rotary valve, and this mixes immediately with the dry charge. Dry material overflows through a downcomer to an integral after-cooler. An alternative design of this type of dryer is one in which a thin bed is used. 

The synthesis of chloromethylsilatrane is carried out in steel enameled reactor 5 with an agitator and a water vapour jacket. First the reactor is loaded with ethyl alcohol and freshly distilled triethanolamine from batch boxes a calculated amount of potassium hydroxide is loaded through a hatch. The mixture is intensively agitated, the temperature raised till KOH dissolves completely, as shown by the appearance of reflux in the rundown box situated after cooler 4. Then chloromethyltriethoxysilane is fed at such speed that the reactive mixture boils uniformly. After the reaction is finished, the mixture is cooled to 15°C, sent to nutsch filter 6 and filtered through coarse calico. The technical chloromethylsilatrane in the nutsch filter is washed with ethyl alcohol twice, thoroughly pressed and dried in draft 7 at a temperature below 100 °C till its weight is constant. 

The product of catalytic regrouping is loaded from collector 15 into tank 18, which has an agitator, a water vapour jacket and packed tower 19. A residual pressure of 0.08-0.09 GPa is created in the tank the contents are heated to 120-150 °C and the volatile products are distilled, until the viscosity is 35-55 mm2/s and active hydrogen content in the oligomer (Hact) reaches 0.13-0.25%. The volatile products after cooler 20 are collected into... 

Fig. 7.6. Spray dryer for production of coarse food powders with instant properties [29]. (1) Liquid feed system. (2) Spray dryer chamber. (3) Drying air heater. (4) Cyclones for fines recovery. (5) Vibrofluidizer as after-dryer. (6) Vibrofluidizer as after-cooler. (7) Fines return to drying chamber.

Additional methanol is injected into the gas between the two reactors. The reactors contain many tubes filled with FK-2 catalyst, where methanol and oxygen react to make formaldehyde. Reaction heat is removed by a bath of boiling heat-transfer oil. Hot oil vapor is condensed in the waste-heat boiler (5), thus generating steam at up to 40 bar pressure. Before entering the absorber (7), the reacted gas is cooled in the after cooler (6) and reheats the circulating oil from the process-gas heater (2). 

Through the final stage of compression and the after cooler, the water content remains unchanged, about 3.65 g/Sm3, and liquid water does not form and there is no need for a scrubber on the discharge. At 50°C and 11 MPa the stream can hold 13.5 g/Sm3 and thus is well under saturated. 

Catalyst lines between the reactor and the stripper had to be lined with Hastelloy B, and Hastelloy B valves had to be used. All nozzles in the reactor were similarly protected. Double extra-heavy 4-in. carbon-steel pipes were used in the reactor after cooler and replaced periodically. 

Pipes in a compressor circuit should connect directly point-to-point. Bends instead of elbows cause less friction loss and less vibration. Angular branch connections eliminate hard tees and give a smoother flow. Double offsets for a directional change should be avoided. Intercoolers closely integrated with the machine minimize piping. Pulsation dampeners should be located on the cylinders without any interconnecting pipe. Knockout drums should be adjacent to the machine. Several after-coolers or exchangers in the circuit should be stacked as much as possible for a direct gas flow. Equipment in the circuit should be in process flow sequence. 

In view of the fact that the water content in the bottoms product of the pressurized column is twice that of the prerun column, the hydrocarbons transferred ftom the prerun column into the pressurized column will reliably be found in the bottoms product, i.e. they are transferred to the atmospheric distillation column. Thus, ethanol becomes the key component for the pressurized column. Since the bottom product of the pressurized column - unlike that of the atmospheric column - does nOt have to meet certain purity requirements, this column need not have a side outlet for ethanol, but the ethanol is quantitatively transferred to the atmospheric columit. The high methanol content in the bottom of the pressurized column facilitates ethanol separation. Nevertheless, for the same number of trays, the pressurized operation of this column leads to a higher reflux than in the atmospheric column. The bottoms product ftom the pressurized column is transferred to the atmospheric column at approximately 125-35°C. The overhead product is obtained at approximately 115-125°C, condensed in the reboiler of the atmospheric column, and fed to the reflux drum of the pressurized column. From there, some of the overhead product is withdrawn by way of an after-cooler as on-spec methanol while the rest is pumped back uncooled as reflux to the column head. 

Also End flash gas used for diyer bed regeneration is currently at higher temperature due to design deficiencies in the EFG compressor after cooler. This is impacting final cooling temperature of the molecular sieve beds. 

Water temperature Before cooler After cooler... 

The very large numbers of installations of the PCHF on offshore platforms has ably demonstrated the PI benefits which result from their use - namely the opportunities given to innovative offshore operators to cut costs through improved safety and greatly reduced topside platform size and weight. This is visible in specific areas such as compressor after coolers, gas coolers, gas dehydration trains and cryogenic processes for the removal of inerts from streams. 

When a gas is compressed, the molecules that make up the gas are moved closer together. This increases the chances of molecular collisions that produce heat and increase the pressure beyond the normal calculated compression ratio. Figure 14-7 shows a typical compressor system, illustrating the various components and process variables associated with the system as it is started up. The scientific comparison is between the initial conditions or process variables and the operating variables. (This figure does not show an inner-cooler or an after-cooler, to illustrate what happens when these systems are not used.) The starting pressure is 14.7 psia and final pressure is 35 psia. Using the formula T2 = P2 x Ti Pi, it is possible to observe the operation of the scientific laws that takes place when the compressor is started up. As the pressure increases, so does the temperature. 

The actual capital expenditure associated with the various types of clinker cooler is liable to vary greatly from one case to another, especially if after-coolers and/or elaborate noise control measures have to be included. In every case where complete utilization of the exhaust air from the cooler is possible, the multiple-stage grate cooler with circulating air system will involve the lowest capital outlay. 

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