Liquifier

Calor gas, Calor propane The trade name for a liquified petroleum gas (LPG) sold in cylinders for domestic and industrial healing. Calor gas is the name used for commercial butane while commercial propane is sold as Calor propane. 

This equation describes the additional amount of gas adsorbed into the pores due to capillary action. In this case, V is the molar volume of the gas, y its surface tension, R the gas constant, T absolute temperature and r the Kelvin radius. The distribution in the sizes of micropores may be detenninated using the Horvath-Kawazoe method [19]. If the sample has both micropores and mesopores, then the J-plot calculation may be used [20]. The J-plot is obtained by plotting the volume adsorbed against the statistical thickness of adsorbate. This thickness is derived from the surface area of a non-porous sample, and the volume of the liquified gas. 

Notes. (1) the acid mixture may be prepared (compare Section 11,49,1) by placing 120g. (37.5ml) of bromine and 130g. of crushed ice in a 500ml. flask, cooling the latter in ice, and passing sulphur dioxide (from a siphon of the liquified gas) into the bromine layer at such a rate that the gas is completely absorbed. The flask is shaken occasionally, and the flow of gas is stopped immediately the red colour due to free bromine has disappeared the mixture... 

Many commercial gases are generated by burning hydrocarbons (qv) eg, natural gas or propanes, in air (see Gas, natural Liquified petroleum gas). The combustion process, especially the amount of air used, determines the gas composition. For a given fuel-to-air ratio, the gas composition can be used to determine the water vapor content required to achieve a desired equiUbrium carbon content of the austenite (see Combustiontechnology). 

A good example is liquid nitrogen, which liquifies, at atmospheric pressure, at -198°C glued by Van der Waals forces between the covalently bonded N2 molecules. The... 

Figure 3-6. Scheme for liquifying methane using the cascade refrigeration system. 

In summary, starting with 105°F gas at atmospheric pressure, the theoretical work necessary to liquify one pound of methane is 510.8 Btu or 352 hp/MMcfd. The simplified liquefaction process, as illustrated, uses a turboexpander/compressor and a small propane refrigeration unit. The 41.25% efficiency breaks down as follows one-fourth contributed by the turboexpander/compressor at 35.8% efficiency one-sixteenth contributed by the mechanical propane refrigeration unit at 43% efficiency, at a moderate temperature where its efficiency is high and a large fraction—eleven-sixteenths—contributed at 58.2% efficiency by compression and Joule-Thomson condensation energy. 

Dr. Judson Swearingen ealeulated the power requirement of his eyele to be 900 hp/MMsefd of gas liquified. In other units this figure beeomes 1,239 Btu/lb or 5.80 kw-hr/lb-mole. This eorresponds to a thermodynamie effieieney of 41.25% based on the minimum possible work for a eompletely reversible eyele. As before, this is ealeulated by means of the following equation readily derived from the two laws of thermodynamies ... 

Cryogenic processes using turboexpanders facilitate high levels of ethylene recovery from refinery gas while producing byproducts of hydrogen- and methane-rich gas. In a cryogenic process, most of the ethylene and almost all of the heavier components are liquified and ethylene is separated from this liquid. 

Power is generated by the pressurized gas expanding through an 11,000 rpm single-stage, radial-inflow turbine expander, which drives a synchronous generator. Exhaust gas from the expander is liquified by air-cooled condensers and is pumped back to the heat exchangers to repeat the cycle. 

As stated earlier, turboexpanders are normally used in cryogenic processes to produce isentropic expansion to cool down the process gas. Two common applications are natural gas processing plants and chemical plants. In natural gas processing plants, turboexpanders are installed to liquify heavier hydrocarbon components and produce lean natural gas with specified dew point limits to meet required standards. 

The turboexpander lowers the temperature of the product to -100°F, causing it to liquify. Now at 350 psig pressure, the liquid from this process enters the demethanizer tower where it mingles with the previously introduced stream of liquid. The turboexpanders provide a 92% recovery rate while the former system, a backup Joule-Thomson valve, was able to provide only a 60% recovery rate. The volume of gas entering the turboexpanders can vary up to 10% yet, the different flowrates do not significantly affect the efficiency of these units, which are rated at 2,400 hp at 16,000 rpm. 

The Satanta plant went online in September 1993, processing natural gas from some 1,000 wells drilled in the Hugoton fields of southern Kansas. A day s production yields 13,000 bbl of liquified natural gas (LNG), 5.1 million Nm (190 MMscf) of residue natural gas, and 21,600 Nm (800,000 scf) of helium. 

The extraction process at BP-Amoco Empress begins with natural gas arriving at the plant at about 15°C and 600 psi pressure. The gas is dehydrated to a -90°C dewpoint by means of molecular sieves. Still at 600 psi, the gas is introduced into heat exchangers and cooled to -70°C, at which point it begins to liquify in a separator. 

Propane is the next hydrocarbon in this series, and its molecular formula is CjHg which is one carbon and two hydrogen atoms different from ethane. Propane is an easily liquified gas which is used as fuel. 

The next hydrocarbon in the series is butane, another rather easily liquified gas used as a fuel. Together, butane and propane are known as the LP (liquified petroleum) gases. Butane s molecular formula is C4H,q, which is CHj bigger than propane. 

ESTIMATING EVAPORATION LOSSES FROM LIQUIFIED GASES... 

Liquified gases are sometimes stored in well-insulated spherical containers that are vented to the atmosphere. Examples in the industry are the storage of liquid oxygen and liquid ammonia in spheres. If the radii of the inner and outer walls are r, and r, and the temperatures at these sections are T, and T, an expression for the steady-state heat loss from the walls of the container may be obtained. A key assumption is that the thermal conductivity of the insulation varies linearly with the temperature according to the relation ... 

The inputs required for the calculation are the radii, iimer and outer temperatures, and thermal conductivities at the two temperatures. This expression enables an estimate of the heat flow into a spherical storage tank containing liquified gas. 

Observable Characteristics - Physical State (as normally shipped) Compressed liquified gas Color. Colorless Odor. Pungent extremely pungent. 

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