HIGH PRESSURE TECHNOLOGY

Design of thick-walled cylinders, Design of removable closures, Manufacture of pressure vessels. Manufacture of tubing. 

During the nineteenth century the growth of thermodynamics and the development of the kinetic theory marked the beginning of an era in which the physical sciences were given a quantitative foundation. In the laboratory, extensive researches were carried out to determine the effects of pressure and temperature on the rates of chemical reactions and to measure the physical properties of matter. Work on the critical properties of carbon dioxide and on the continuity of state by van der Waals provided the stimulus for accurate measurements on the compressibiUty of gases and Hquids at what, in 1885, was a surprisingly high pressure of 300 MPa (- 3,000 atmor 43,500 psi). This pressure was not exceeded until about 1912. 

High Pressure in the Chemical Industry. The use of high pressure in industry may be traced to early efforts to Hquefy the so-called permanent gases using a combination of pressure and low temperature. At about the same time the chemical industry was becoming involved in high pressure processes. The discovery of mauveine in 1856 led to the development of the synthetic dye industry which was well estabUshed, particularly in Germany, by the end of the century. Some of the intermediate compounds required for the production of dyes were produced, in autoclaves, at pressures of 5-8 MPa (725-1160 psi). 

Imperial Chemical Industries (ICI) operated a coal hydrogenation plant at a pressure of 20 MPa (2900 psi) and a temperature of 400—500°C to produce Hquid hydrocarbon fuel from 1935 to the outbreak of World War II. As many as 12 such plants operated in Germany during World War II to make the country less dependent on petroleum from natural sources but the process was discontinued when hostihties ceased (see Coal conversion PROCESSES,liquefaction). Currentiy the Fisher-Tropsch process is being used at the Sasol plants in South Africa to convert synthesis gas into largely ahphatic hydrocarbons at 10—20 MPa and about 400°C to supply 70% of the fuel needed for transportation. 

Other Industrial Applications. High pressures are used industrially for many other specialized appHcations. Apart from mechanical uses in which hydrauhc pressure is used to supply power or to generate Hquid jets for mining minerals or cutting metal sheets and fabrics, most of these other operations are batch processes. Eor example, metallurgical appHcations include isostatic compaction, hot isostatic compaction (HIP), and the hydrostatic extmsion of metals. Other appHcations such as the hydrothermal synthesis of quartz (see Silica, synthetic quartz crystals), or the synthesis of industrial diamonds involve changing the phase of a substance under pressure. In the case of the synthesis of diamonds, conditions of 6 GPa (870,000 psi) and 1500°C are used (see Carbon, diamond, synthetic). 

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I. L. Spaia and J. P. Paauwe, High Pressure Technology, Marcel Dekker, Inc., New York, 1977. 

Pressure Vessels and Piping. Some of the most critical components of a chemical plant involve pressure vessels. A thorough knowledge of the American Society of Mechanical Engineers (ASME) Pressure Vessel Code (75) is essential for design and maintenance of chemical plants. Some states have their own codes, which usually conform closely to the ASME version (see High pressure technology Tanks and pressure vessels). 

Berty, J. M., J. O. Hambrick, T. R. Malone, and D. S. Ullock, 1969, Reactor for Vapor-Phase Catalytic Studies Paper No. 42 E, presented at the Symposium on Advances of High Pressure Technology, Part II, 64th Nat. Meeting of AIChE, New Orleans, LA, March 16-20. 

High Pressure Technology Association (1975) High Pressure Safety Code, Leeds. 

R.A. Graham, in High Pressure Technology, Sixth AIRAPT Conference, Vol. 2, Applications and Mechanical Properties, edited by K.D. Timmerhaus and... 

The methods reported in these and other patents are plagued by low yields furthermore they normally necessitate the use of high pressure technology. The expensive precious metal catalyst must be recovered and reused. In most cases, selectivity and reaction rates deteriorate when recycled catalyst is used. No reports of adequate recovery of catalyst activity have been found. 

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