Steam ethylene

The accumulation of di(2-ethylhexyl) phthalate in platelet-poor plasma stored for seven and 14 days in PVC bags sterilized by steam, ethylene oxide or irradiation revealed seven-day storage levels of di(2-ethylhexyl) phthalate of 378 19, 362 10 and 275 15 mg/L, respectively, and 14-day storage levels of 432 24, 428 22 and 356 23 mg/L, respectively (Dine et al., 1991). 

Plastic components (whether container or closure) can be sterilized using steam, ethylene oxide, hydrogen peroxide, or ionizing radiation. The y irradiation is accomplished off-site by a subcontractor with appropriate expertise as these methods are considered the province of specialists because of the extreme health hazards directly related to the sterilization method. Electron beam sterilization may also be done by a contractor, although compact lower energy electron beam systems have been introduced that allow sterilization in-house. Steam sterilization is ordinarily performed in house, though many common components are becoming available presterilized by the supplier. Preparation steps prior to sterilization vary with the component and the methods used to produce the component. Rubber components are washed to reduce particles, while this is less common with plastic materials. 

Table 1. Manufacturers of Steam, Ethylene Oxide Sterilizers, and Dry Heat Sterilizers...

Exercise 3.7.7. Calculate the maximum conversion of ethylene to alcohol by catalytic vapor-phase hydration at 300°C and 30 atm using an initial steam-ethylene mole ratio of 10. Assume the vapors behave as ideal gases. The following thermodynamic data are available ... 

If the initial steam-ethylene ratio is 5 and a basis of 1 mole of ethylene is chosen, a material balance gives the following results for equilibrium conditions ... 

Steam + Ethylene - Carbon monoxide + Hydrogen Reaction (5) ... 

The Shell process, now in commercial operation (see process description) uses a phosphoric acid-on Celite catalyst to effect a 4.2 per cent once-through conversion. Mace and Bonilla showed that a tungsten oxfde-on silica gel catalyst was the most effective of several types investigated. Yields of 4.6 mole per cent were obtained at optimum conditions of 580 F (300 C), 2,000 psi pressure, steam ethylene mole ratio of 1, and a space velocity of 1,500 reciprocal hours. 

Effect of Operating Variables. The direct hydration of ethylene is an equilibrium i eaction (see Sec. V) which is favored by low temperatures, high pressures, and high steam. ethylene ratios. He catalytic activity of the phosphoric acid catalyst increases with increasing temperature, decreases with increasing pressure because of lower concentration, and decreases with high steam ethylene ratios at hi pressures because of moisture absorption. Thus, the process conditions that favor ethanol production adversely affect the catalyst activity. For this reason, operating conditions must necessarily be chosen on the basis of economic considerations. 

There are times when a researcher wants to predict a specific x value from a y value as well as generate confidence intervals for that estimated x value. For example, in microbial death kinetic studies (D values), a researcher often wants to know how much exposure time (x) is required to reduce a microbial population, say, three logs from the baseline value. Alternatively, a researcher may want to know how long an exposure time (x) is required for an antimicrobial sterilant to reduce the population to zero. In these situations, the researcher will predict x from y. Many microbial death kinetic studies, including those using dry heat, steam, ethylene oxide, and gamma radiation. 

Traditional applications of polycarbonate in the medical market, such as filter housings, tubing connectors, and surgical staplers, have relied on the materials unique combination of strength, purity, transparency, and ability to stand all sterili2ation methods (steam, ethylene oxide gas, and gamma radiation). Polycarbonate-based blends blends and copolymers have further extended the materials usefulness to medical applications. 

As a function of the temperature, at 30 atm, and steam/ethylene molar ratio equals... 

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