Townsend process

Townsend Process, 841 IFP Clauspol 1500 Process, 843 Wiewiorowski Process, 846 UCBSRP Process, 846... 

The first sulfur dioxide-based process was the Townsend process, developed in 1958. This process never advanced beyond the pilot-plant stage due to mechanical and corrosion problems. It was followed by the IFF Clauspol 1500 and the Wiewiorowski processes in 1969. The IFF process is closely related to the Townsend process, but is restricted in application to the treatment of Claus tail gas. The low cost and simplicity of the IFF process has attracted some commercial interest however, the Wiewiorowski process was never commercialized. 

In 1986, the University of California at Berkeley conducted extensive bench scale research on a process similar to the original Townsend process, but using a different physical solvent and a new catalyst formulation. This process has been named the UCBSRP process, but in spite of its scientific interest, it has not attracted the funding needed to be scaled up to the pilot-plant stage. 

The Townsend process, which was disclosed by Reid and Townsend (1958) and Townsend and Reid (1958), and described in a patent granted to Townsend (1965), was proposed as a method for high-pressure natural gas desulfurization and elemental sulfur production in one operation, thus combining the conventional process of absorbing hydrogen sulfide in an aqueous alkaline solution (e.g., ethanolamine), followed by processing the stripped H2S in a Claus-type sulfur plant. However, the process is claimed to be equally applicable to the treatment of acid-gas streams, such as the effluents from ethanolamine plant regenerators. In this application, the Townsend process would be a substitute for the Claus plant. 

Figure 9-47. Typical flow diagram of Townsend process for high-pressure natural gas treating.

A process, very similar to the Townsend process, was disclosed by Renault (1969) and Barthel et al. (1971) of Institut Francais du Petrole (IFP). This process was named Clauspol 1500 and developed specifically for the removal of hydrogen sulfide and sulfur dioxide from Claus unit tail gases. 

This region is often referred to as the Townsend breakdown region, in which — with little or no further change in voltage — the current can rise by several orders of magnitude, e.g., from Kh to 10" A. There is usually a spark produced during the initiation of this process. The current flow is controlled by the size of the resistance in the external voltage circuit. 

Townsend, D., Ferguson, El., and Kohlhrand, El., Applieation of ARCtm Thermokinetie Data to the Design of Safety Sehemes for Indusuial Reaetors, Process Safety Progress, 14 (1), pp. 71-76, 1995. 

Townsend, G. F. (1975). Processing and storing liquid honey. In "Book of Honey", (E. Crane, Ed.), pp. 269-292. Oxford University Press, Oxford. 

The use of the pinch technology method in the design of heat exchanger networks has been outlined in Sections 3.17.1 to 3.17.6. The method can also be applied to the integration of other process units such as, separation column, reactors, compressors and expanders, boilers and heat pumps. The wider applications of pinch technology are discussed in the Institution of Chemical Engineers Guide, IChemE (1994) and by Linnhoff et al. (1983), and Townsend and Linnhoff (1982), (1983), (1993). 

Townsend, D. W. and Linnhoff, B. (1983) AIChEJI 29, 742. Heat and power networks in processes design. 

Dearden, J. C. Townsend, M. S., Digital computer simulation of the drug transport process, in Proc. 2nd Symp. Chemical Structure-Biological Activity Relationships Quantitative Approaches (Suhl), Akademie-Verlag, Berlin, 1978, pp. 387-393. 

Linnhoff B, Townsend DW, Boland D, Hewitt GF, Thomas BEA, Guy AR and Marsland RH (1982) A User Guide on Process Integration for the Efficient Use of Energy, IChemE, Rugby, UK. 

Townsend DW and Linnhoff B (1983) Heat and Power Networks in Process Design, AIChE J, 29 742. 

Satzger H, Townsend D, Zgierski MZ, Patchkovskii S, Ullrich S, Stolow A (2006) Primary processes underlying the photostability of isolated DNA bases adenine. Proc Natl Acad Sci USA 103 10196-10201... 

The few examples of deliberate investigation of dynamic processes as reflected by compression/expansion hysteresis have involved monolayers of fatty acids (Munden and Swarbrick, 1973 Munden et al., 1969), lecithins (Bienkowski and Skolnick, 1974 Cook and Webb, 1966), polymer films (Townsend and Buck, 1988) and monolayers of fatty acids and their sodium sulfate salts on aqueous subphases of alkanolamines (Rosano et al., 1971). A few of these studies determined the amount of hysteresis as a function of the rate of compression and expansion. However, no quantitative analysis of the results was attempted. Historically, dynamic surface tension has been used to study the dynamic response of lung phosphatidylcholine surfactant monolayers to a sinusoidal compression/expansion rate in order to mimic the mechanical contraction and expansion of the lungs. 

Townsend A process for removing hydrogen sulfide from natural gas by absorption in triethylene glycol containing sulfur dioxide. Part of the sulfur produced is burnt to sulfur dioxide in order to provide this solution. The hydrogen sulfide and sulfur dioxide react in the presence of water to generate elemental sulfur. Invented in 1959 by F. M. Townsend. 

In order to achieve breakdown, electrons (either from the air or from the body) must be accelerated to a sufficient velocity to ionize the air and breed more electrons by any one of several processes. In an actual gas, however, some of the kinetic energy of the electrons is lost in collisions with air molecules without resulting in ionization. This combined effect has been expressed in terms of the Townsend ionization coefficient. As a body becomes smaller, its curvature increases and the electric field intensity drops off more rapidly with distance from the surface consequently, to accelerate electrons a given amount, the body surface field intensity must be higher than for a flat surface. Actually, because of increased attenuation resulting from the increased distance that an electron must travel through air to achieve a given acceleration, the required surface intensity must increase even faster. 

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