Linde liquefaction process

Grassmann diagram for the Linde liquefaction process of methane. One thousand exergy units of compression energy result in 53 exergy units of liquid methane. The thermodynamic efficiency of this process is 5.3%. The arrowed curves, bent to the right, show the losses in the various process steps. 

The Linde liquefaction process, which depends solely on throttling expansion, is shown in Fig. 9.6. After compression, the gas is precooled to ambient temperature. It may be even further cooled by refrigeration. The lower the temperature of the gas entering the throttle valve, the greater the fraction of gas that is liquefied. For example, a refrigerant evaporating in the cooler at 233.15 K (—40°C) provides a lower temperature at the valve than if water at 294.15 K (21°C) is the cooling medium. 

Comparing the Efficiency of the Simple and Linde Liquefaction Processes... 

Figure 5.1-2 The more efficient Linde liquefaction process.

The most important part of the physical processing of the gases was their compression. To achieve this under previously untried industrial conditions Bosch had to seek out powerful leak-proof gas compressors, far more robust than those employed in mines and the low temperature Linde liquefaction process."... 

The industry got its start in 1895 when Dr. Carl von Linde, a pioneer in refrigeration technology, received the first patent for the liquefaction and rectification of air into its major components oxygen and nitrogen (Almqvist, E., IOMA). Georges Claude soon developed this work further in Paris, France, improving the efficiency of the liquefaction process. 

Hydrogen and helium have very low inversion temperatures, i.e., -80°C, and -240°C, respectively. Thus, at ordinary temperatures, these gases get heated up instead of being cooled in Joule-Thomson s expansion. But, if hydrogen is first cooled below -80°C and helium below -240°C, then these gases also get cooled down on Joule-Thomson expansion. Joule-Thomson effect was used by Linde in the liquefaction of the gases. The Linde s process is described below ... 

Brodyanskii, V. M., "Thermodynamic Analysis of Gas-Liquefaction Processes Part I. Basic Methods of Analysis and Part II. Analysis of Air Liquefaction by Linde Process," Inzhnerno-Fizicheskii Zhurnal, (>, No. 7 and... 

Linde Also called Hampson-Linde. A process for separating oxygen and nitrogen from air by liquefaction followed by fractional distillation. Developed by K.P.G. von Linde in Germany and W. Hampson in England at the start of the 20th century. 

Fig. 4.7. Schematic for precooled Linde air liquefaction process described in Example 4.6.

Application of this method to an actual process can best be demonstrated by a numerical example. Consider a simple nitrogen liquefaction process using the simple Linde cycle shown previously in Fig. 4.4b. Conditions for this process are indicated in Table 4.2. Assuming, for simplicity, that there is no heat... 

Table 4.3. Summary of Losses Associated with Simple Linde Nitrogen Liquefaction Process...

The Linde single-column separation system is obtained by replacing the liquid reservoir of the simple Linde liquefaction cycle with a stripping column. However, any of the other liquefaction processes could be used just as well to furnish liquid for the column. 

Figure 5.11 Liquefaction of gases using Joule—Thomson expansion, (a) Basic liquefaction process using Joule-Thomson expansion and b) Linde process.

Claude process A process similar to the Linde process for the liquefaction of air, except that additional cooling is produced by allowing the expanding gas to do external work. 

Linde-Frank- Caro Process.—The most important ethod of producing hydrogen, in which chemical and lysical methods are employed, is one in which the emical process results in the production of blue water 5, and the physical in the separation of the chemical mpounds (chiefly carbon monoxide) from the hydrogen liquefaction. 

Figure 6.38 is the Claude gas liquefaction system, a modification of the Hampson-Linde gas liquefaction system. The Claude system has a turbine in the expansion process to replace a part of the highly irreversible throttling process of the Hampson-Linde system. From state 1 to state 10, the Claude system processes are the same as those of the Hampson-Linde system. After the gas is cooled to state by the regenerative cooler (heat... 

The liquefaction train is the novel mixed fluid cascade process (MFCP) patented by Statoil/Linde. It is the first LNG base-load plant ever to employ electric drive for the compressors. Today the Oman plant (Shell) is claimed to be world s most efficient LNG plant as it consumes only 8% of the gas for its operation. When Snohvit goes on stream (2006) it is expected to become even more efficient as it will consume only 5% of the feed gas for the liquefaction. This means that Snohvit will constitute the most efficient LNG plant ever. The high efficiency is attainable much owing to the low temperature of the ambient air and the cooling water in the artic region. 

Linde-Frank-Caro A process for extracting hydrogen from water-gas by liquefaction. 

The efficiency of this process, that is, the amount of liquefied gas produced for each unit of work done in the compressor, can be improved upon by better engineering design. For example, instead of merely discarding the low-temperature, low-pressure gas leaving the flash drum (stream 5), the gas can be used to cool the high-pressure gas upstream of the throttle valve and then returned to the compressor, so that none of the gas is wasted or exhausted to the atmosphere. This process, referred to as the Linde process, is shown in Fig. 5.1-2. In this way the only stream leaving the liquefaction plant is liquefied gas. and, as shown in Illustration 5.1-1, more liquefied gas is produced per unit of energy expended in the compressor. 

The 99.8 per cent pure nitrogen necessary for the nitrification of the carbide is separated froiii the atmosphere through a liquefaction and distillation process. Either one of two systems is generally used, the Claude or the Linde. The cost of the nitrogen is exceedingly small as compared with its fixation cost. When nitrogen fixation is spoken of, the accent should be on the fixation, rather than the nitrogen from a cost consideration. 

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