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Unformatted text preview: process from 425.8 to 415.2 kg/m3 (about 3 percent),
which makes us question the validity of the incompressible substance assumption. Still, this assumption enables us to obtain reasonably accurate results
with less effort, which proves to be very convenient in the absence of compressed liquid data. EXAMPLE 7–8 Economics of Replacing a Valve by a Turbine A cryogenic manufacturing facility handles liquid methane at 115 K and 5 MPa
at a rate of 0.280 m3/s . A process requires dropping the pressure of liquid
methane to 1 MPa, which is done by throttling the liquid methane by passing it
through a flow resistance such as a valve. A recently hired engineer proposes to
replace the throttling valve by a turbine in order to produce power while dropping the pressure to 1 MPa. Using data from Table 7–1, determine the maximum amount of power that can be produced by such a turbine. Also, determine
how much this turbine will save the facility from electricity usage costs per year
if the turbine operates continuously (8760 h/yr) and...
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This document was uploaded on 11/28/2012.
- Spring '09