Adiabatic throttle

Process 3 Process without heat exchangers Wl and W2 extraction temperature t equals the solvent exit temperature t2 of the pump or compressor V, separation temperature t equals temperature t5 behind the adiabatic throttle valve D ... 

EX13 incl. REF- PRO 2.91 1.9 + cooling (9-97 MW) by means of a refrigerating process arbitrary choice of parameters NHg-refrigera-tor, low pressure 1.32 bar, pressure ratio 10.8, compression power 1+ -77 MW, adiabatic throttling... 

Steam is produced at 70 bar and some unknown temperature. A small amount of steam is bled off just before entering a turbine and goes through an adiabatic throttling valve to atmospheric pressure. The temperature of the steam exiting the throttling valve is 400°C. The unthrottled steam is fed into the turbine, where it is adiabatically expanded to atmospheric pressure. 

A 0.2-m tank containing helium at 15 bar and 22°C will be used to supply 4.5 moles per minute of helium at atmospheric pressure using a controlled adiabatic throttling valve. 

The adiabatic throttle is a reasonable model for any partially open valve, the... 

Solid carbon dioxide can be manufactured by expanding liquid CO through an adiabatic throttling valve. If CO2 is available for the process as a saturated liquid at 800 psia and the expansion reduces the pressure to 14.7 psia, how many pounds of solid carbon dioxide are produced per pound of liquid CO2 ... 

Here, F, Zf and h are, respectively, the molar flow rate, mole fraction of component of i and total enthalpy, all in cell k their subscripts, ret and perm, refer to retentate and permeate streams. Equations (10.4) and (10.5) are mass balances and mass-transfer equations for each of the components present in the membrane feed. The cross-flow model [Equations (10.3)-(10.7)] was implemented in ACM v8.4 and validated against the experimental data in Pan (1986) and the predicted values of Davis (2002). The Joule-Thompson effect was validated by simulating adiabatic throttling of permeate gas through a valve in Aspen Hysys. Both these validations are described in detail in Appendix lOA. 

For further cooling of a fluid, a common procedure is to use a continuous throttling process in which the fluid is forced to flow through a porous plug, valve, or other constriction that causes an abrupt drop in pressure. A slow continuous adiabatic throttling of a gas is called the Joule-Thomson experiment, or Joule-Kelvin experiment, after the two scientists who collaborated between 1852 and 1862 to design and analyze this procedure. ... 

Steam at 300 psia and 540 F expands through an adiabatic throttling valve to 100 psia ... 

Since the gas spends so little time in the plug, there is no opportunity for heat transfer thus, we consider this process adiabatic. Additionally, the shaft work is zero. If kinetic energy effects are negligible, the first law for this steady-state, adiabatic throttling process reduces to ... 

Steam Rate Enthalpy data can be obtained from Mollier diagrams or from steam tables (see Sec. 2), from which the theoretical steam rate can be calculated. For example, a throttle inlet condition of 4137 kPa (600 psig) and 399° C (750° F) gives an enthalpy of 3.2 MJ/kg (1380 Btu/lb), and if the end point is at 348 kPa (50 psig), then adiabatic expansion is to 2.69 MJ/kg (1157 Btu/lb). This gives 0.52 MJ/kg (223 Btu/lb) available, and the theoretical steam rate is calculated from the Btu equivalent per Idlowatthour or horsepower-hour ... 

Assume a process each for the eight devices (1) turbines as adiabatic with 80% efficiency, (2) splitters as nonisopar-ametric devices, and (3) condensers as isobaric processes. Notice that throttling devices are automatically constant enthalpy processes. 

Find the compressor power required, turbine power produced, heating load, and COP for a heat pump that uses R-12 as the working fluid and is designed to operate at an evaporator saturation temperature of 2°C and a condenser saturation temperature of 39°C. The mass rate flow of R-12 is 0.32 kg/sec. The throttling valve is replaced by an adiabatic turbine with 74% efficiency. 

Assume the throttling process is adiabatic and isenthalpic Guess vapor fraction (x) x = 0.5... 

Saturated steam at 30(psia) is throttled to l(atm) and mixed adiabatically with (and < by) 40-wt-% sulfuric add at 10O(°F) in a flow process that raises the temperature of the 1 180(°F). How much steam is required for each pound mass of entering acid, and what concentration of the hot add ... 

For the throttle and separator, we assume adiabatic operation thus Stotai(throttle) = S4z + S5(l - z) - S3... 

Ten kilograms per second of superheated steam at 400°C and 1 lOOkPa is throttled to 125 kPa adiabatically through a valve. Determine the work loss if the surroundings are at 298.15 K. 

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