From refinery feeds

Butanes are recovered from raw natural gas and from petroleum refinery streams that result from catalytic cracking, catalytic reforming, and other refinery operations. The most common separation techniques are based on a vapor—Hquid, two-phase system by which Hquid butane is recovered from the feed gas. 

Multiple reactors achieve 95-96% conversion and recovery, and stringent air pollution legislation has now pushed this to 99%. A similar sequence of reactions is used for sulfur production from crude oil except that the organosulfur compounds must first be removed from the refinery feed and converted to H2S by a hydrogenation process before the sulfur can be recovered. 

A better method of increasing LCO yield is through better fractionation upstream. The removal of the fraction under 650°F from the feed requires better stripping. The total refinery yield of diesel will increase when the light ends are fractionated from the feed (Table 6-1). Some of the catalytic routes to maximize LCO yield are ... 

In addition to the presence of these elements in ores, they are also available from recycled feeds, such as catalyst wastes, and as an intermediate bulk palladium platinum product from some refineries. The processes that have been devised to separate these elements rely on two general routes selective extraction with different reagents or coextraction of the elements followed by selective stripping. To understand these alternatives, it is necessary to consider the basic solution chemistry of these elements. The two common oxidation states and stereochemistries are square planar palladium(II) and octahedral platinum(IV). Of these, palladium(II) has the faster substitution kinetics, with platinum(IV) virtually inert. However even for palladium, substitution is much slower than for the base metals so long as contact times are required to achieve extraction equilibrium. 

Feed stock for the first sulfuric acid alkylation units consisted mainly of butylenes and isobutane obtained originally from thermal cracking and later from catalytic cracking processes. Isobutane was derived from refinery sources and from natural gasoline processing. Isomerization of normal butane to make isobutane was also quite prevalent. Later the olefinic part of the feed stock was expanded to include propylene and amylenes in some cases. When ethylene was required in large quantities for the production of ethylbenzene, propane and butanes were cracked, and later naphtha and gas oils were cracked. This was especially practiced in European countries where the cracking of propane has not been economic. 

Hydrotreated shale oil has an advantage as a refinery feed. In contrast to most petroleum crude oils, it contains essentially no residuum. Properties of the hydrotreated product from whole shale oil are similar to those of distillate fractions from waxy petroleum Arabian or Sumatran crudes. An exception is the sulfur content which is much lower for hydrotreated shale oil than for most crudes. 

Ethylene is produced commercially in a variety of different processes. Feed stocks for these various processes range from refinery gas, ethane, propane, butane, natural gasoline, light and heavy naphthas to gas and oil and heavier fractions. Prepare three different qualitative flow sheets to handle a majority of these feed stocks. What are the advantages and disadvantages of each selected process ... 

Naphtha cracking provides about 4.3 million tonnes of propylene per year, which is out of a total demand for propylene in excess of 5.3 million tonnes per year. The difference (about 20%) is made up by propylene extracted from refinery off-gases, particularly FCC operations (used to produce gasoUne from heavier feed stocks such as heavy gas-oil or residua). 

The same effects were seen with mixed olefin feeds. The refinery stream described in Table III was blended with C.P. Grade Isobutane to obtain a 9.0-to-l.O Isobutane-to-olefln molar ratio. This feed was alkylated at temperatures ranging from to 45°C. The contact time was held constant at 1.0 minutes. The results are shown in Table IV. The alkylate compositions include pentanes derived from the feed, but only... 

The most significant impurities in the feed streams to a typical alkylation unit are ethylene, dlolefins, sulfur compounds and water. Corrosion Inhibitors and other chemicals used in upstream processing can also be present in some cases, and these can have harmful effects. The amount of each iaqiurlty that reaches the alkylation reactor varies considerably from refinery to refinery. If accurately determined and properly accounted for, these impurities can explain an appreciable percentage of the acid make-up reported by various operating units. The impurity data shown in Table I can be used to evaluate the merit of Improved upstream process control and/or more efficient feed pretreatment methods. 

Figure 5 El mass spectra of coke concentrates obtained from the residue refinery feed, top scan taken at 55 C and the bottom scan at 490PC. 

The liquid product obtained from thermal cracking can be either catalytically cracked/ hydrocracked or co-processed with a refinery feed. Since the catalytic cracking of oil derived from MWP is more or less problematic, any cracking catalyst can be applied to oil derived from pyrolysis of plastics. But the yield and the quality of gasohne obtained from cracking step vary with the type of catalyst and the properties of the pyrolytic oil derivated from waste plastics. 

The products obtained by refining and upgrading heavy crude oils are largely determined by market demand. The consumption of transport fuels is always such as to focus attention on the conversion of lighter [1] or heavier [2] feed stocks to appropriate distillation cuts. The processing of heavy residual oils into lighter oils is now widely practised, although the methods used may vary from refinery to refinery [3,4],... 

Subsequently, over several months, the demo unit reliably operated on a nearly continuous basis (except for holiday shut-down periods) while producing high quality product. The unit utilizes piped slipstreams of actual refinery feeds. To date, we have tested both predominantly C4 olefin and mixed C3/C4 olefin feed streams, and the demo has produced alkylate of comparable quality to that from Fortum s Porvoo Refinery HF alkylation unit. 

Because of the impact of the sieves and of hydrocracking Ocker-bloom and Stuart (43) of Sun Oil have projected, on the basis of the gasoline market, that economically recoverable propylene from refineries will remain relatively constant—in the range of 14 to 16 billion lbs/year through 1975. Figure 2 shows their prediction the upper limit results from operations to maximize conversion to gasoline, and the lower limit results from operations to minimize feed capacity. They also predict that... 

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