Propylene and propane

Some small amount of byproduct formation occurs. The principal byproduct is di-isopropyl ether. The reactor product is cooled, and a phase separation of the resulting vapor-liquid mixture produces a vapor containing predominantly propylene and propane and a liquid containing predominantly the other components. Unreacted propylene is recycled to the reactor, and a purge prevents the buildup of propane. The first distillation in Fig. 10.3a (column Cl) removes... 

After epoxidation, propylene oxide, excess propylene, and propane are distilled overhead. Propane is purged from the process propylene is recycled to the epoxidation reactor. The bottoms Hquid is treated with a base, such as sodium hydroxide, to neutralize the acids. Acids in this stream cause dehydration of the 1-phenylethanol to styrene. The styrene readily polymerizes under these conditions (177—179). Neutralization, along with water washing, allows phase separation such that the salts and molybdenum catalyst remain in the aqueous phase (179). Dissolved organics in the aqueous phase ate further recovered by treatment with sulfuric acid and phase separation. The organic phase is then distilled to recover 1-phenylethanol overhead. The heavy bottoms are burned for fuel (180,181). 

Because of the low relative volatiHty, fractionation of propylene and propane is even more difficult than the fractionation of ethylene and ethane. 

Although the blast effects of the East St. Louis tank-car accident (NTSB 1973) were found to be highly asymmetric, average TNT equivalencies of 10% on an energy basis and 109% on a mass basis were found. These equivalencies were calculated based on the assumption of a full tank-car inventory (55,000 kg) of a mixture of propylene and propane. 

The use of methane, ethane, ethylene, propylene, and propane pure light hydrocarbons as refrigerants is quite common, practical, and economical for many hydrocarbon processing plants. Examples include ethylene manufacture from cracking some feedstock, ethylene or other hydrocarbon recycle purification plants, gas-treating plants, and petroleum refineries. 

Methane, carbon dioxide, ethylene, propylene, and propane 25 m Poraplot R column, 30-100° at 5°/min. 

Alkanes and Alkenes. For this study, C150-1-01 and C150-1-03 were tested under primary wet gas conditions with ethylene, ethane, propylene, and propane being added to the feed gas. This study was made in order to determine whether these hydrocarbons would deposit carbon on the catalyst, would reform, or would pass through without reaction. The test was conducted using the dual-reactor heat sink unit with a water pump and vaporizer as the source of steam. All gas analyses were performed by gas chromatography. The test was stopped with the poisons still in the feed gas in order to preserve any carbon buildup which may have occurred on the catalysts. 

Stream 4. At 245 K, chlorine, ammonia, propylene and propane could all be chosen. In principle, ethane and ethylene could also have been included but at 245 K they are too close to their critical temperature and would require significantly higher refrigeration power than the other options. The safety problems associated with chlorine are likely to be greater than ammonia. Thus, ammonia might be a suitable choice of refrigerant. Choosing a component already in the process would be desirable. 

From the values of y and the pressure ratios, it is clear that the pressure ratio for ammonia is very high for a single-stage compression. The guidelines for gas compression given in Chapter 13 indicate that propylene and propane compressions should be able to be achieved in a single compression stage, but the ammonia would seem to require two compression... 

In principle, ammonia is the best refrigerant fluid in terms of power requirement. However, this conclusion disregards the potential practical problems associated with compression. There is little to choose between propylene and propane in terms of the power requirements. 

The influence of soot on NO removal in non-thermal plasma has been investigated by Dorai and Kushner and Dorai et al. [88,89] in the presence of propylene and propane. Soot particles were assumed to contain only C and H atoms, and were denoted (C Hy). Soot may undergo oxidation when reacting with O and OH radicals generated in the... 

A 50-50 mixture of propylene and propane is charged at 100 lbmol/hr at 300 F and 365 psia. Propylene conversion of 80% is required. A 25 75 mixture of C6 and C9 is made. Find the volume of catalyst needed at constant temperature. 

Martin and coworkers described an application of optimization to an existing tower separating propane and propylene. The lighter component (propylene) is more valuable than propane. For example, propylene and propane in the overhead product were both valued at 0.20/lb (a small amount of propane was allowable in the overhead), but propane in the bottoms was worth 0.12/lb and propylene 0.09/lb. The overhead stream had to be at least 95 percent propylene. Based on the data in Table E12.4A, we will determine the optimum reflux ratio for this column using derivations provided by McAvoy (personal communication, 1985). He employed correlations for column performance (operating equations) developed by Eduljee (1975). 

The distillation column used in this example separated a binary mixture of propylene and propane. Because of the low relative volatility and large number of trays, the dominant time constant is very large (500 minutes). Despite this large time constant, a sampling period of 9.6 minutes gave poor results. The period had to be reduced to 1,8 minutes to get good identification, both dynamic and steadystate gain. 

The reasons for the three grades are very practical. For the first two, refinery and chemical, that s the way they re made. Refinery grade propylene streams are generally by-products of a refinery s cat cracker, and the propane/propylene ration is determined by the way the cat cracker is run to make gasoline, not propylene. Chemical grade propylene is usually produced in a naphtha or gas oil cracker. The ratio of propylene and propane is about 92 8 over most of the operating conditions. 

Soil Boesten et al. (1992) investigated the transformation of [ C]l,2-dichloropropane under laboratory conditions of three subsoils collected from the Netherlands (Wassenaar low-humic sand, Kibbelveen peat, Noord-Sleen humic sand podsoil). The groundwater saturated soils were incubated in the dark at 9.5-10.5 °C. In the Wassenaar soil, no transformation of 1,2-dichloropropane was observed after 156 d of incubation. After 608 and 712 d, however, >90% degraded to nonhalogenated volatile compounds, which were detected in the headspace above the soil. These investigators postulated that these compounds can be propylene and propane in a ratio of 8 1. Degradation of 1,2-dichloropropane in the Kibbelveen peat and Noord-Sleen humic sand podsoil was not observed, possibly because the soil redox potentials in both soils (50-180 and 650-670 mV, respectively) were higher than the redox potential in the Wassenaar soil (10-20 mV). 

Pawela Crew and Madix [144] have investigated desorption of propylene and propane from Ag(llO) with the emphasis put on the anomalous effects of weak chemisorption on desorption kinetics of alkenes. Molecular conformation of styrene on Ag(lOO) related to the catalytic epoxidation of terminal alkenes has been studied by Williams etal. [145]. IR studies of the adsorption structures of 1,3-butadiene at Ag(lll) and Au(lll) surfaces have been published by Osaka et al. [146]. 

Processes based on propane ammoxidation to manufacture acrylonitrile have also been developed,915 966 and BP has announced commercialization.966 Dehydrogenation at high reaction temperature (485-520°C), which is about 100°C higher than for propylene ammoxidation, results in the formation of propylene, which subsequently undergoes normal ammoxidation. Despite higher investments and the markedly lower selectivity (30-40%), the process can be economical because of the price difference between propylene and propane.966 Better selectivites can be achieved at lower (40-60%) conversions. 

Very low-boiling hydrocarbons, such as methane, are normally distilled at pressures of about 70% of their critical pressure. Of course, all distillations must be carried out below the critical temperature in order to provide liquid reflux. Ethylene and ethane are usually distilled at 40%-55% of critical pressure, while propylene and propane are distilled at 35%-50% of critical pressure. 

One possible arrangement for a hydrofluoric acid alkylation unit is shown schematically in Fig. 1. Feedstocks are pretreated, mainly to remove sulfur compounds. The hydrocarbons and acid are intimately contacted in the reactor to form an emulsion, within which the reaction occurs. The reaction is exothermic and temperature must be controlled by cooling water. After reaction, the emulsion is allowed to separate in a settler, the hydrocarbon phase rising to the top. The acid phase is recycled. Hydrocarbons from the settler pass to a fractionator which produces an overhead stream rich in isobutane. The isobutane is recycled to the reactor. The alkylate is the bottom product of tile fraetionater (isostripper). If the olefin teed contains propylene and propane, some of the isoshipper overhead goes to a depropanizer where propane is separated as an overhead... 

Shimadzu, A., Miyazaki,T., Maeda, M. and Ikeda, K. (2000) Relationship between the chemical structure and the solubility diffusivity and permselectivity of propylene and propane in 6-FDA-based polyimides. Journal of Polymer Science Part B-Polymer Physics, 38, 2525. 

This effluent then goes to a condenser where aldehydes and by-products drop out this mixture is removed in a separator. The liquid stream from the separator contains appreciable amounts of dissolved gases, mainly propylene and propane. A product stripping column distills these out. The liquid stream from this stripper goes through two distillation columns in series that remove iso- and n-butyraldehyde as overhead products, respectively. A small stream that contains heavy by-products formed in the reactor leaves the bottom of the second column. This stream can be combined with the heavy ends stream from the n-butanol column and valuable aldehydes and alcohols recovered for recycle. The iso-butyraldehyde overhead product from the first aldehyde column may be hydrogenated and sold as a low cost solvent, cracked to synthesis gas and recycled to the oxo reactors, or burned as fuel. 

Separation of the C2 stream to produce high-purity ethylene and ethane requires a large tower, sometimes the largest one in the plant. Separation of the C3 stream to produce high-purity propylene and propane also requires a large tower, and in some plants it is the largest one. Separation of butadiene from the C4 stream, if performed, is usually accomplished by extractive distillation. Aromatics are frequently recovered and separated to obtain benzene, toluene, and xylenes, especially when heavy feedstocks are used. 

The product of interest is propylene and propane which are contaminated with propyne (methyl acetylene), allene and cyc/o-propane. A typical composition is given in Table 5.1. 

There are few significant industrial uses for these other materials and they are reduced by selective hydrogenation to propylene and propane. 

A series of runs was made in the alonized Incoloy 800 reactor by using ethylene, ethane, propylene, and propane. These runs were com-... 

---