Compressor Power

While theoretical compressor power requirements are reduced slightly by going to lower evaporating temperatures, the volume of vapor to be compressed and hence compressor size and cost increase so rapidly that low-temperature operation is more expensive than high-temperature operation. The requirement of low temperature for fruit-juice concentration has led to the development of an evaporator... 

Ward reported power consumption for a plant using the mixed-refrigerant cycle. Compressor power was 9,460 kw for an LNG production rate of 28,550 m /hr. This converts to 3.37 kw-hr/lb-mole of liquid. The minimum work for a feed-gas pressure of 37 atm, an assumed feed-gas temperature of 80°F, and an assumed heat-sink temperature of 80°F = 1.09 kw-hr/lb-mole of liquid. This gives an efficiency of 32.4%. 

Figure 5-4. Compressor power versus mass flow.

The compressor train is driven by the motor/generator, which has a pair of clutches that enable it to act as a motor when the compressed air is being generated for storage in the cavern, declutches it from the expander train, and connects it to the compressor train. The compressor train consists of a three-section compressor each section having an intercooler to cool the compressed air before it enters the other section, thus reducing the overall compressor power requirements. 

Gas temperature is an important quantity when designing gas transmission lines, since pipelines are designed for large flows and their consequent higher compressor requirements. The compressor power required at each station depends to a great extent on the gas temperature. Rowing gas temperature must be controlled to a... 

Theoretical Compressor Power for a Refrigerant-12 Plant Requiring 10 Tons at 44°F, 30 Tons at 34°F, and 20 Tons at 24°F... 

Make and Model Compressors-Power Cyls. Bore 8 Stroke ... 

Halloran, J., Take a Closer Look at Control of Centrifugal Compressors, Power, Dec. (1986). 

The total compressor power input is the net power delivered to the compressor drive shaft by the prime mover system. This is... 

Evaporator load + compressor power = condenser load... 

Example 6.6 The hardness of water in Coventry is given as a maximum of 560 ppm (parts per million) and the water treatment can permit a concentration of solids to 1200 ppm. The cooling capacity is 700 kW and the compressor power 170 kW. How much water should be bled to waste and what is the total make-up required ... 

In summary, increasing the number of beds in series for the system shown in Figure 12 decreases the volume of recycle somewhat more than proportionately to the number of beds, decreases the recycle compressor power requirements somewhat, and has no effect on the catalyst volume. On balance, it would appear that the capital savings achieved by increasing the number of beds will be minimal. 

A measure of the energy which dissipates in the bubble column can be derived from the adiabatic compressor power ... 

A definite correlation of the results of the measurements can be achieved by using the adiabatic compressor power per unit volume of reactor according to Eq. (10) which is shown in Fig. 15 [27]. The experimentally determined loss factor is required in Eq. (10). The measured data for spargers with holes dL= 0.2 - 2 mm can be correlated with Eq. (24). 

Fig. 15. Reference floe diameter dp for bubble columns versus mass related adiabatic compressor power PJqV...

Calculation of the compressor power and energy requirements (see Chapter 3). 

The compressor efficiency (in this case, isentropic efficiency) can now be calculated and in turn the polytropic coefficient. This allows the outlet temperature to be calculated, together with the compressor power. 

Natural gas (methane) is transported through an uninsulated 6 in. ID commercial steel pipeline, 1 mi long. The inlet pressure is 100 psi and the outlet pressure is 1 atm. What are the mass flow rate of the gas and the compressor power required to pump it T) = 70°F, /rgas = 0.02 cP. 

Air intakes to heating and ventilation systems, air compressors for process, instrument and breathing air, and to prime movers for gas compressors, power generation and pumps should be located as far as practical from contamination by dust, toxic and flammable materials release sources. They should not be located in electrically classified areas. If close to possible vapor releases (as confirmed by dispersion analyses( they should be fitted with toxic or combustible gas detection devices to warn of possible air intakes hazards and snutdown and isolate the incoming air ductwork and fans. 

Volvo is also a partner in another European project, the Capril project, which is managed by Volkswagon. A fuel cell VW Golf was built to run on methanol. Volvo developed the compressor, power converter and energy control system. 

For large quantities of hydrogen, pipeline delivery is cheaper than any other option. Pipelines are characterised by very low operating costs, mainly for compressor power, but high capital costs. The investment for pipelines is in proportion to the delivery distance, while the influence of capacity is lower. 

Cooling towers and utility areas (boilers, air compressors, power generation). 

An engine operates on the open Brayton cycle and has a compression ratio of 8. Air, at a mass flow rate of 0.1 kg/sec, enters the engine at 27°C and 100 kPa. The amount of heat addition is IMJ/kg. Determine the efficiency, compressor power input, turbine power output, back-work ratio, and net power of the cycle. Show the cycle on a T-s... 

An engine operates on the closed Brayton cycle (Fig 4.8) and has a compression ratio of 8. Helium enters the engine at 47°C and 200 kPa. The mass flow rate of helium is 1.2 kg/sec and the amount of heat addition is 1 MJ/kg. Determine the highest temperature of the cycle, the turbine power produced, the compressor power required, the back-work ratio, the rate of heat added, and the cycle efficiency. 

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