Illustrate Refrigeration of Nitrogen-hydrogen by using suitable diagrar
Answers
Explanation:
Energy and Exergy Analyses of Gas Liquefaction Systems
Several cycles, some complex and others simple, exist for the liquefaction of gases. Here, we consider the Linde-Hampson (LH) cycle, shown schematically and on a T-s diagram in Figure 15.1, to illustrate energy and exergy analyses of liquefaction cycles. Makeup gas is mixed with the uncondensed portion of the gas from the previous cycle, and the mixture at state 1 is compressed by an isothermal compressor to state 2. The temperature is kept constant by rejecting compression heat to a coolant. The high-pressure gas is further cooled in a regenerative counterflow heat exchanger by the uncondensed portion of gas from the previous cycle to state 3, and throttled to state 4, which is a saturated liquid–vapor mixture state. The liquid (state 6) is collected as the desired product, and the vapor (state 5) is routed through the heat exchanger to cool the high-pressure gas approaching the throttling valve. Finally, the gas is mixed with fresh makeup gas, and the cycle is repeated.
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FIGURE 15.1. Schematic and temperature-entropy diagram for a simple LH liquefaction cycle.
The refrigeration effect for this cycle may be defined as the heat removed from the makeup gas in order to turn into a liquid at state 6. Assuming ideal operation for the heat exchanger (i.e., the gas leaving the heat exchanger and the makeup gas are at the same state as state 1, which is the compressor inlet state), the refrigeration effect per unit mass of the liquefied gas is given by:
(15.1)