Discharge temperature

Filtration and water-knockout systems are used to clean up the gas before it enters a compressor. Cooling systems are sometimes required to maintain compressor discharge temperatures below 54°C to avoid damage to the pipeline s protective coatings. Automated compressor stations are typically staffed by maintenance and repair personnel eight hours per day, five days per week. Other stations are staffed on a 24-hour basis because personnel must start, stop, and regulate compressors in response to orders from the dispatch office. 

A more obvious energy loss is the heat to the stack flue gases. The sensible heat losses can be minimized by reduced total air flow, ie, low excess air operation. Flue gas losses are also minimized by lowering the discharge temperature via increased heat recovery in economizers, air preheaters, etc. When fuels containing sulfur are burned, the final exit flue gas temperature is usually not permitted to go below about 100°C because of severe problems relating to sulfuric acid corrosion. Special economizers having Teflon-coated tubes permit lower temperatures but are not commonly used. 

Two-stage systems should be seriously considered when the evaporating temperature is below—20°C. Such designs will save on power and reduce compressor discharge temperatures, but will increase initial cost. 

With a depth of 5 ft, total volume of the pond would amount to a 45.5-h holdup, which is more than the 24-h holdup required to maintain a fairly constant discharge temperature throughout the day. 

For estimating purposes for direct-heat drying applications, it can be assumed that the average exit-gas temperature leaving the sohds bed wih approach the final solids discharge temperature on an ordi-naiy unit carrying a 5- to 15-cm-deep bed. Calculation of the heat load and selec tion of an inlet-air temperature and superficial velocity (Table 12-32) will then permit approximate sizing, provided an approximation of the minimum required retention time can be made. 

Ethylene oxidation was studied on 8 mm diameter catalyst pellets. The adiabatic temperature rise was limited to 667 K by the oxygen concentration of the feed. With the inlet temperature at 521 K in SS and the feed at po2, o=T238 atm, the discharge temperature was 559 K, and exit Po =1.187 atm. The observed temperature profiles are shown on Figure 7.4.4 at various time intervals. The 61 cm long section was filled with catalyst. 

Monitoring should include the usual parameters worthy of surveillance in high-speed turbo machinery the temperature of journal bearings, vibration and axial position of the pinions, inlet and discharge temperatures combined with discharge pressure from the individual compressor stages, and various lube oil system devices. Competent manufacturers make sure all measurement locations are completely prewired on the machine and made available at predefined interfaces or in terminal boxes for connection at the plant site. 

Several constraints were faced in the design phase of the project. For example, special attention was given to the fact that 400 Series stainless steel, carbon, and some grades of aluminum were not compatible with the process. Additionally, the expander discharge temperature was required to stay between 35-70°F. The operating rpm of the expander wheel was determined by the rpm required by the third stage of the air compressor. 

There are several methods available to avoid problems with low discharge temperature. One solution is auxiliary heating. The gas can be heated upstream of the expander this is called pre-heating. The gas can also be heated downstream of the expander, known as post-heating. 

Composition by mol%, volume %, or weight %. To what extent does composition vary Corrosive effects. Limits to discharge temperature, which may cause problems with the gas. Quantity to Be Handled, for Each Stage Stage quantity and unit of measurement. 

DATA INPUT Ambient Preseure Compressor Inlet Pressure Compressor Discharge Pressure Compressor Inlet Temperature Compressor Discharge Temperature Compressor Speed... 

K = Adiabatic exponent, Cp/Cv N = Polytropic exponent, (N - 1)/N - (K Pi, P- = Suction, discharge pressures, psia Ti, = Suction, discharge temperatures, °R Ep = Polytropic efficiency, fraction... 

Calculate the suction capacity, horsepower, discharge temperature, and piston speed for the following single-stage double acting compressor. 

Step 2. At this point the discharge temperature must be calculated to arrive at a value for the discharge compressibility. 

The discharge temperature should be limited to 300°F as recommended by API 618. Higher temperatures cause problems with lubricant coking and valve deterioration. In nonlube service, the ring material is also a factor in setting the temperature limit. While 300°F doesn t seem all that hot, it should be remembered that this is an average outlet temperature, whereas the cylinder will have hot spots exceeding this temperature. 

Suction temperature Discharge temperature Suction pressure Discharge pressure Isentropic exponent Specific gravity Percent clearance ... 

The screw compressor can be evaluated using the adiabatic work equation. Discharge temperature can be calculated by taking the adiabatic temperature rise and dividing by the adiabatic efficiency then multiplying by the... 

Power requirements and discharge temperatures are calculated using the same relationships as used with the other rotary compressors already discussed. The efficiency is. 80 for air service and pressure in the 30 psig range. The mechanical losses are higher than the other rotaries. The mechanical loss is variable and dependent on gas, lubrication, and other factors. For an estimate, use. 15 of the gas horsepower. This approxuna tion should be close enough for an estimate. 

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