Linde dual-pressure system

Linde dual-pressure system, precooled to 228 K, observed — 3580 0.201... 

Another modification of the basic Claude cycle is the dual-pressure Claude cycle, similar in principle to the Linde dual-pressure system presented in Fig. 4.8. In this dual-pressure cycle, shown in Fig. 4.17, only the gas that is sent through the expansion valve is compressed from the low pressure to the high pressure this reduces the w ork requirement per unit mass of gas liquefied. To illustrate the advantage of the Claude dual-pressure cycle over the Linde dual-pressure cycle, Barron has shown that, in the liquefaction of air, the liquid yield can be doubled while the work per unit mass liquefied can... 

Develop a plot that provides the work required to liquefy a unit mass of nitrogen in the Linde dual-pressure system of Fig. 4.8 as a function of the intermediate pressure for intermediate flow rate ratios, m,/m, of 0.5, 0.6, 0.7, and 0.8. The lower and upper operating pressures of the liquefier are 0.101 and 30.3 MPa, respectively. Assume isothermal and reversible compression at 300 K for the compressors and 100% effectiveness for the heat exchanger. 

A Linde dual-pressure system is used to liquefy air. The high-pressure air leaves the compressor at 20.2 MPa and is cooled to 293 K before entering the counterflow heat exchanger. The returning intermediate pressure air stream leaves the three-channel heat exchanger at... 

Example 4.9. Find the theoretical liquid yield, work per unit mass liquefied, and the figure of merit for a simple Linde dual-pressure liquefaction system using air as the working fluid. The liquefier operates between 0.101 and 20.2 MPa. Inlet and exit temperatures for both compressors are maintained at 293 K. The intermediate pressure is 3.03 MPa and the flow-rate ratio, w,/aw, of this stream is 0.80. What is the work per unit mass liquefied and the figure of merit if the simple Linde cycle had been used to accomplish the liquefaction ... 

The Linde-Frankl system using patented Frankl regenerators was developed in the 1930s to meet the huge demands for oxygen and nitrogen by the steel and chemical industries. The liquefaction part of this system is very similar to an ammonia-precooled dual-pressure Claude liquefaction system and thus operates with about one-half of the power consumed by the Linde double-column system. 

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