Steam intercooled

Space needs to be provided for the auxiliaries, including the lube oil and seal systems, lube oil cooler, intercoolers, and pulsation dampeners. A control panel or console is usually provided as part of the local console. This panel contains instmments that provide the necessary information for start-up and shutdown, and should also include warning and trouble lights. Access must be provided for motor repair and ultimate replacement needs to be considered. If a steam turbine is used, a surface condenser is probably required with a vacuum system to increase the efficiency. AH these additional systems need to be considered in the layout and spacing. In addition, room for pulsation dampeners required between stages has to be included. Aftercoolers may also be required with knockout dmms. Reference 8 describes the requirements of compressor layouts and provides many useful piping hints. 

Figure 6-28E. Steam requirement correction for two-stage unit with barometric intercooling. By permission, Fondrk, V. V., Petroleum Refiner, V. 37, No. 12, 1958 [3].

The second step is to develop several conceptual plants (e.g., cycles A, B, and C) to meet the identified need. One of the several plants is described in Example 5.14. In this example, a three-stage regenerative steam Rankine cycle and a four-stage intercool and four-stage reheat air Brayton cycle are combined to meet the need. 

Figure 7.18. Heavy-duty centrifugal, axial, and reciprocating compressors, (a) Section of a three-stage compressor provided with steam-sealed packing boxes (DeLaval Steam Turbine Co.), (b) An axial compressor (Clark Brothers Co.), (c) Double-acting, two-stage reciprocating compressor with water-cooled jacket and intercooler (Ingersoll-Rand Co.).

A two-stage double-acting compressor with water cooled cylinder jackets and intercooler is shown in Figure 7.18(c). Selected dimensional and performance data are in Table 7.7. Drives may be with steam cylinders, turbines, gas engines or electrical motors. A specification form is included in Appendix B. Efficiency data are discussed in Section 7.6, Theory and Calculations of Gas Compression Temperature Rise, Compression Ratio, Volumetric Efficiency. 

The cooling water circuit provides river water (at 20°C) to the steam condenser and compressor intercooler. The use of stainless... 

The cooling-water circuit provides cooling water for the steam condenser and for the compressor intercooler. Since these units are constructed from mild steel, the cooling water used can be either sea water, river water or scheme water. Probably the second option is best because there are no further equipment materials requirements and this water is free. The total circulation through this cooling-water loop is approximately 120 000 kg (120 cubic metres). 

The synthesis gas is compressed to 80 atm in a two barrel centrifugal compressor driven by an extraction condensing steam turbine. The compressor usually has three stages of intercooling. 

As mentioned in Chap. 3, other means of cooling may be employed besides circulating a fluid around the catalyst tube. Dividing the reactor into parts with intercoolers between each part (see Fig. 13-3) is a common procedure. Another scheme which has worked satisfactorily for reactions of moderate heat of reaction, such as the dehydrogenation of butene, is to add a large quantity of an inert component (steam) to the reaction mixture. 

Power plants under about 350 MWe cannot use the latest high-efficiency combined cycle technologies. Those below about 250 MWe cannot use particularly high-efficiency steam turbines because of friction losses and leaks in small dimension gas paths. Those below about 100 MWe cannot economically use reheat steam cycles, giving a further efficiency drop. Moving further down in size gives a steady reduction in efficiency of the gas turbine, whichever manufacturer is selected. The scale effect of gas turbine efficiencies is due to flow paths and pressure drops and can only be partly compensated for with additional components such as intercoolers or reheaters. 

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