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Joule Thomson expansion

Simple Linde or Joule-Thomson Expansion Cycle [Pg.110]

The simple Linde cycle may also be used as a liquefier for fluids that have an inversion temperature that is above ambient temperature. Under such circumstances, the refrigeration duty, Q, is replaced by a draw-off stream of mass rhf representing the liquefied mass of fluid that is continuously withdrawn from the reservoir. Note that under these conditions, only the unliquefied mass of fluid is warmed in the counter-current heat exchanger and returned to the compressor. An energy balance around the heat exchanger, expansion valve, and liquid reservoir now results in [Pg.112]

This is equivalent to saying that the high pressure p2 which minimizes A2 is the pressure at which the Joule-Thomson coefficient is zero for a temperature of. In other words, for maximum liquid yield, point 2 on Fig. 4.4c should [Pg.112]

To account for heat inleak, into the system, the relation in Eq. (4.18) needs to be modified to [Pg.113]

Example 4.3. A simple Linde liquefaction system operates between 290 K and 71.9 K and uses nitrogen as the working fluid. The gas is isothermally and reversibly compressed to 10.1 MPa. The low pressure corresponds to the saturation pressure of liquid nitrogen at 71.9 K (0.05 MPa). Assuming ideal heat exchangers and no heat inleak to the system, what is the liquid yield and FOM for this liquefier  [Pg.113]

An apparatus for the Joule-Thomson expansion of a gas. The apparatus consists of a cylinder with pistons on both ends. Between the pistons is a porous plug which allows gas molecules to pass slowly from one side to the other. By external mechanical means, the pressure on the left is maintained at some value Pj, and the pressure on the right is Pj, with Pj Pj. The whole apparatus is insulated and does not exchange heat with the surroundings. [Pg.73]

Notice that if the choice of piston pressures is such that gas moves from the left to the right, then AVi 0 and AV2 0. Since the process is carried out adiabatically, q = 0, and therefore, AU = w. The enthalpy change for the entire system is zero this is an isenthalpic (constant enthalpy) process. [Pg.74]

when the temperature on the left, Ty is measured and the temperature on the right, T2, is measured, we can evaluate at such instant in the process the quantity (T2 - T])/(P2 - Pj)- If the experiment is repeated with a decreasing difference between the pressure on the left and the pressure on the right, this quantity will approach 3T/9P. The variable that is held constant in this derivative quantity is H because the setup insures an isenthalpic process. This derivative is called the Joule-Thomson coefficient  [Pg.74]

Taking P and T as the independent variables of the enthalpy fimction [i.e., H = H(P, T)], a rule of partial differentiation (see Appendix A) leads to the following relation among partial derivatives. [Pg.74]

The partial derivatives on the right side are the Joule-Thomson coefficient and the constant pressure heat capacity. [Pg.74]

The field of cryogenics involves the production of very low temperatures, and the study of the behavior of matter at these temperatures. These low temperatures are needed to evaluate third-law entropies using calorimetric measurements. There are some additional interesting thermodynamic applications. [Pg.156]

A gas can be cooled by expanding it adiabatically with a piston (Sec. 3.5.3), and a liquid can be cooled by pumping on its vapor to cause evaporation (vaporization). An evaporation procedure with a refrigerant fluid is what produces the cooling in an ordinary kitchen refrigerator. [Pg.156]

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.  [Pg.156]

The principle of the Joule-Thomson experiment is shown in Fig. 6.2. A tube with thermally insulated walls contains a gas maintained at a constant pressure p at the left [Pg.156]

After the gas has been allowed to flow for a period of time, a steady state develops in the tube. In this steady state, the gas is assumed to have a uniform temperature T at the left side of the plug and a uniform temperature T (not necessarily equal to T ) at the right side of the plug. [Pg.157]

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  [Pg.299]

We call a process that occurs at constant enthalpy, such as this one, isenthalpic. [Pg.299]

We can determine the change in temperature that results as the pressure decreases in the isenthalpic throttling process if we know the derivative, dT/dP)h- We call this relation the Joule-Thomson coefficient, /x.jt- [Pg.299]

We can use the thermodynamic web to develop an expression for /tjt in terms of PvT property relations and heat capacities. We begin with Equation (5.37)  [Pg.300]

We must use the real heat capacity given by Equation (5.39). During the Joule-Thomson expansion, dh is zero thus, we can rewrite the previous equation as  [Pg.300]


Hydroearbon dew point eontrol is aehieved by eooling the gas. There are three eooling alternatives free expansion or Joule-Thomson expansion, external refrigeration, and using a turboexpander. Joule-Thomson expansion does not always produee the needed refrigeration over the life of the plant and, henee, is not eonsidered as a viable... [Pg.70]

Option 1 Initial Installation—Joule-Thomson Expansion... [Pg.73]

Figure 3.5 In the Joule-Thomson expansion, a volume of gas V, is pushed through a porous plug by a piston at pressure pt. The gas expands to a volume V2 against a second piston at a pressure p2. Figure 3.5 In the Joule-Thomson expansion, a volume of gas V, is pushed through a porous plug by a piston at pressure pt. The gas expands to a volume V2 against a second piston at a pressure p2.
Thus, the Joule-Thomson expansion is an isenthalpic process. [Pg.140]

Figure 3.6 shows how pressure and temperature are related for a series of isenthalpic (Joule-Thomson) expansions. For example, if we start at the... [Pg.140]

We will show later that /o x. = 0 for an ideal gas. Thus the change in temperature resulting from a Joule-Thomson expansion is associated with the non-ideal behavior of the gas. [Pg.141]

The Joule-Thomson expansion can be used to liquify gases. An expansion at pressure and temperature conditions inside the dashed line envelope where /o r < 0 cools the gas. This gas is used to precool the incoming gas so that the expansion occurs at still lower temperatures. Continuing this process eventually cools the gas until it liquifies. [Pg.141]

Thus, nj T = 0 for the ideal gas, and the change in temperature during the Joule-Thomson expansion depends upon non-ideal behavior of the gas. [Pg.142]

K to 500 K. A Joule-Thomson expansion in this range of pressure and temperature will cool the gas and can be used to liquify Ni.k Equations of state can be used to predict /zjt. and T. ... [Pg.144]

Joule-Thomson expansion 118, 139 45 junction potential in electrochemical cells 490... [Pg.659]

The essential features of the earlier commercial models were that the two piston engines were vertically arranged inside the large finned heat exchanger in a static atmosphere of helium with LHe from the Joule-Thomson expansion collecting in the bottom of the dewar. This liquid could be either used in situ or transferred to all external storage dewar. The energy of expansion was absorbed in a crosshead on top of the dewar assembly. [Pg.140]

For laboratory production of LHe, other so-called Collins-type liquefiers have been built with one or two stages of GM cooling before the Joule-Thomson expansion (e.g. ref. [50]). The thermodynamic analysis of Collins helium liquefaction cycle can be found in ref. [51]. [Pg.140]

Josephson junctions, 23 820, 821 Josephson string, 23 827 Josephson vortex, 23 827 Jost Report, 15 201, 202 Joule-Thompson effect, 12 374 Joule-Thomson expansion, 24 647, 648, 650-651... [Pg.501]

Joule-Thomson expansion cycle, 8 42-43 Joule-Thomson expansion coefficients, for hydrogen, 13 764 Journal bearing, 15 211 Journal of Biotechnology and Bioengineering, 11 10 Journal of Physical and Chemical Reference Data, 15 141, 769 Journal of Research of the National... [Pg.501]

Figure 5.9 The Joule-Thompson cycle (Linde cycle). The gas is first compressed and then cooled in a heat exchanger, before it passes through a throttle valve where it undergoes an isenthalpic Joule-Thomson expansion, producing some liquid. The cooled gas is separated from the liquid and returned to the compressor via the heat exchanger. Figure 5.9 The Joule-Thompson cycle (Linde cycle). The gas is first compressed and then cooled in a heat exchanger, before it passes through a throttle valve where it undergoes an isenthalpic Joule-Thomson expansion, producing some liquid. The cooled gas is separated from the liquid and returned to the compressor via the heat exchanger.
Let us now analyze the conditions of the Joule-Thomson expansion in more detail. From the adiabatic character ([Pg.93]

From (3.63) and (3.64), we recognize that AU = — A(PV), i.e., that Joule-Thomson expansion occurs under conditions of constant enthalpy ... [Pg.93]

The third law is concerned with the nature of entropy (Sidebars 5.10-5.13) and thermodynamic behavior in the limiting approach toward T = OK. Although Joule-Thomson expansion (Section 3.6.3) is a useful refrigeration technique down to about 20K (7J for H2), more specialized cryogenic techniques are required to approach the sub-microkelvin (around 10 6K) domain of extreme low temperatures. The most important such technique, adiabatic demagnetization, is described in Sidebar 5.16. [Pg.183]

Figures 4.7 through 4.9 are provided for hydrate limits to isenthalpic Joule-Thomson expansions, such as that which occurs when a gas with entrained free water droplets flows through a valve. A similar set of charts could in principle be determined for hydrate limits to isentropic (AS = 0) expansions such as would occur when a gas flows through a perfect turboexpander of a modern gas processing plant. To date, however, no such charts have been generated. Figures 4.7 through 4.9 are provided for hydrate limits to isenthalpic Joule-Thomson expansions, such as that which occurs when a gas with entrained free water droplets flows through a valve. A similar set of charts could in principle be determined for hydrate limits to isentropic (AS = 0) expansions such as would occur when a gas flows through a perfect turboexpander of a modern gas processing plant. To date, however, no such charts have been generated.
In Figure 8.1 Notz notes that the gas begins to warm (from mile 30 to mile 45) with shallower, warmer water conditions. From mile 45 to mile 50, however, a second cooling trend is observed due to Joule-Thomson expansion. The methanol exiting the pipeline in the vapor, aqueous, and condensate phases is usually not recovered, due to the expense of separation. [Pg.646]

When water-wet gas expands rapidly through a valve, orifice or other restriction, hydrates form due to rapid gas cooling caused by adiabatic (Joule-Thomson) expansion. Hydrate formation with rapid expansion from a wet line commonly occurs in fuel gas or instrument gas lines. Hydrate formation with high pressure drops can occur in well testing, start-up, and gas lift operations, even when the initial temperature is high, if the pressure drop is very large. [Pg.651]

Figure 8.1 shows the pressure and temperature of a pipeline production stream during normal flow with entry into the hydrate formation region. If the gas expands more rapidly, the normal pipeline cooling curve of Figure 8.1 will take on a much steeper slope, but the hydrate formation line remains the same. Two rapid Joule-Thomson expansion curves for a 0.6 gravity gas are shown in Figure 8.7. Intersections of the gas expansion curves with the hydrate formation line (bounding the shaded area) limits the expansion discharge pressures from two different high initial pressure/temperature conditions. Figure 8.1 shows the pressure and temperature of a pipeline production stream during normal flow with entry into the hydrate formation region. If the gas expands more rapidly, the normal pipeline cooling curve of Figure 8.1 will take on a much steeper slope, but the hydrate formation line remains the same. Two rapid Joule-Thomson expansion curves for a 0.6 gravity gas are shown in Figure 8.7. Intersections of the gas expansion curves with the hydrate formation line (bounding the shaded area) limits the expansion discharge pressures from two different high initial pressure/temperature conditions.
Cooling curves such as the two in Figure 8.7 were determined for constant enthalpy (or Joule-Thomson) expansions, obtained from the First Law of Thermodynamics for a system flowing at steady-state, neglecting kinetic and potential energy changes ... [Pg.651]

An alternative, and much more accurate, method for obtaining information on the interactions between molecules is the Joule-Thomson expansion, shown in Fig. 5. This process also forms the experimental basis for much of the science of cryogenics (the study of phenomena at low temperatures), which we will discuss in Chapter 4. Industrially, cryogenic liquids, such as liquid N2, 02, H2, and He, are produced by the Linde process, which uses Joule-Thomson expansions. N2 and 02 (and noble gases) are obtained in this process by producing and then... [Pg.72]

Thus, the initial and final states of a Joule-Thomson expansion he on a curve of constant enthalpy (isoenthalp) and the Joule-Thomson process occurs at constant enthalpy. The Joule-Thomson coefficient, pJT, is defined as... [Pg.74]

We have already seen how gases below their Joule-Thomson inversion temperature (7)) cool upon rapid expansion. By Joule-Thomson expansion, N2 can be liquefied (77 K). Liquid N2 can be used to cool H2 below its Tt (195 K), and then further Joule-Thomson expansion can produce liquid H2 (20.4 K), which can be used to cool He below its Tt (44.8 K). Joule-Thomson expansion of this cooled He can produce liquid He (4.2 K), and reducing the pressure above the liquid can conveniently produce temperatures as low as about 1 K. [Pg.107]

For a single-component, single-phase system or a system at material equilibrium, the change of internal energy is completely determined by the change in two state variables. Thus, Eq. (20) is valid for any process that goes between the initial and final states of the infinitesimal process its application is not limited to reversible processes. It would, for example, apply to a Joule-Thomson expansion, a distinctly nonreversible process. [Pg.115]

Joule-Thomson expansion Expression representing an isenthalpic throttling process. [Pg.170]


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