Phosphoric acid process technology

Production Technology. Processes for extraction of P2O3 from phosphate rock by sulfuric acid vary widely, but all produce a phosphoric acid—calcium sulfate slurry that requires soHds-Hquid separation (usually by filtration (qv)), countercurrent washing of the soHds to improve P2O3 recovery, and concentration of the acid. Volatilized fluorine compounds are scmbbed and calcium sulfate is disposed of in a variety of ways. 

Jacobs-Dorr An alternative name for the Dorr-01iver process for making phosphoric acid, adopted since the technology was acquired by the Jacobs Company in 1974. Twenty seven plants were operating in 1989. 

B. Roland, J. Scholta, H. Wendt, "Phosphoric Acid Fuel Cells - Materials Problems, Process Techniques and Limits of the Technology," in The International Fuel Cell Conference Proceedings, NEDO/MITI, Tokyo, Japan, 1992. 

Lewis and protic acids, usually AICI3 and H2SO4, are used in the liquid phase at temperatures of 40-70°C and at pressures of 5-15 atm. Phosphoric acid on kieselguhr promoted with BF3 (UOP process)309 319 is used in gas-phase alkylation (175-225°C, 30-40 atm). In addition to the large excess of benzene, propane as diluent is also used to ensure high (better than 94%) propylene conversion. This solid phosphoric acid technology accounts for 80-90% of the world s cumene production. 

Figure 19.18. Data of electrochemical fuel cells, (a) Processes in a fuel cell based on the reaction between hydrogen and oxygen, (b) Voltage-current characteristic of a hydrogen-air fuel cell operating at 125°C with phosphoric acid electrolyte [Adlharl, in Energy Technology Handbook (Considine, Ed.), 1977, p. 4.61). (c) Theoretical voltages of fuel cell reactions over a range of temperatures, (d) Major electrochemical systems for fuel cells (Adlharl, in Considine, loc. cit., 1977, p. 4.62).

Higher-purity industrial and food-grade phosphates, until recently, were most often derived from furnace processes. New plants recover purified phosphoric acid suitable for food-grade uses from relatively impure wet process acid, using solvent extraction technology. 

In the case of cumene, UOP introduced a liquid-phase process in the 1940s to compete with aluminum chloride technology. The catalyst is SPA, a solid phosphoric acid catalyst in which the phosphoric acid is supported on silica. Many improvements were made to the SPA catalyst and process over the years, leading to 70% of the world s cumene being produced with SPA by the 1990s. In 1996, UOP introduced the Q-Max process, featuring a zeolitic catalyst and operating in the liquid phase (21). A new Q-Max catalyst, QZ-2001 , was introduced in 2001. 

Cumene capacity topped 9.5 million metric tons in 1998 and is projected to reach 10.4 million metric tons by the end of 2003 (19). Like ethylbenzene, cumene is used almost exclusively as a chemical intermediate. Its primary use is in the coproduction of phenol and acetone through cumene peroxidation. Phenolic resins and bisphenol A are the main end uses for phenol. Bisphenol A, which is produced from phenol and acetone, has been the main driver behind increased phenol demand. Its end use applications are in polycarbonate and epoxy resins. The growth rate of cumene is closely related to that of phenol and is expected to be approximately 5.1% per year worldwide over the next five years. Process technologies for both chemicals have been moving away from conventional aluminum chloride and phosphoric acid catalyzed Friedel-Crafts alkylation of benzene, toward zeolite-based processes. 

Inoue, K. and Nakashio, F., Technology of Uranium recovery from wet-process phosphoric acid (in Japanese). Kemikaru Enjiniaringu 27 (1982) 59-65. 

Hayworth, H.C., Advantages of hquid membrane technology for the extraction of uranium from wet process phosphoric acid. 2nd Chemical Congress of the North American Continent, Division of Fertilizer and Soil Chemistry, 1980. 

Hydrocarbon Technologies, Inc. integrated gasification combined-cycle Kellogg-Rust-Westinghouse process molten carbonate fuel cell methanol-to-gasoline process once-through Fischer-Tropsch process phosphoric acid fuel cell pulverized coal polymer electrolyte fuel cell pressurized fluidized bed combustion 1015 Btu... 

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