Steam pyrolysis

Hydrogen is also a significant by-product of other industrial processes, such as steam pyrolysis (68) of hydrocarbons to produce ethylene (qv), eg,... 

Utilisa tion of shale oil products for petrochemical production has been studied (47—51). The effects of prerefining on product yields for steam pyrolysis of shale oil feed and the suitabiUty of Green River shale oil as a petrochemical feedstock were investigated. Pyrolysis was carried out on the whole oil, vacuum distillate, and mildly, moderately, and severely hydrogenated vacuum distillates. 

Propjiene [115-07-17, CH2CH=CH2, is perhaps the oldest petrochemical feedstock and is one of the principal light olefins (1) (see Feedstocks). It is used widely as an alkylation (qv) or polymer—ga soline feedstock for octane improvement (see Gasoline and other motor fuels). In addition, large quantities of propylene are used ia plastics as polypropylene, and ia chemicals, eg, acrylonitrile (qv), propylene oxide (qv), 2-propanol, and cumene (qv) (see Olefin POLYMERS,polypropylene Propyl ALCOHOLS). Propylene is produced primarily as a by-product of petroleum (qv) refining and of ethylene (qv) production by steam pyrolysis. 

The Coastal process uses steam pyrolysis of isobutane to produce propylene and isobutylene (as weH as other cracked products). It has been suggested that the reaction be carried out at high pressure, >1480 kPa ( 15 atm), to facHitate product separation. This process was commercialized in the late 1960s at Coastal s Corpus Christi refinery. 

The steam pyrolysis of kraft black liquor to yield specific phenolic compounds by thermal decomposition. 

Application To produce polymer-grade ethylene and propylene, a butadiene-rich C4 cut, an aromatic C6-C8 rich raw pyrolysis gasoline, and a high-purity hydrogen by steam pyrolysis of hydrocarbons ranging from ethane to vacuum gas oils. 

The steam pyrolysis of LPG follows the same pathway of that for ethane, namely by a complex branching chain free radical mechanism. This can be divided into initiation, chain propagation and chain termination reactions. This gives rise to a large number of intermediates and products. As with ethane, products of higher carbon number than the feed are formed. 

This chapter comprises part of an experimental program undertaken to provide precise kinetic and product distribution data for the steam pyrolysis of a number of pure olefins, diolefins, and naphthenes over a wide range of temperatures and residence times, including those encountered in industrial practice. Runs were carried out in the bench-scale flow reactor (1), which has been shown (2) to provide yield and conversions data that are in excellent agreement with pilot plant and commercial data. 

Results from this laboratory for steam pyrolysis of isobutene were reported earlier (I), and this chapter describes the pyrolysis of the three normal butene isomers 1-butene, m-2-butene, and trans-2-butene. Reaction schemes are derived from the product distributions, and kinetic parameters are established. 

Table III. Typical Product Yields from Steam Pyrolysis of 1-Butene0...

The following summarizes the yields estimated in this way for Paraho shale oil (in wt % ) olefins (ethylene, propylene, butadiene, 12.2 BTX, 23.5 fuels (including methane), 39.8 coke, 18.3 and hydrogen consumption (net), 0.9. No internal fuel requirements are reflected in these yields. The 36% yield to olefins and BTX could probably be increased significantly by further work, especially on steam pyrolysis to olefins. A bench mark is given in Ref. 8 for a hypothetical petrochemical refinery operated to obtain a 60% yield of BTX and olefins from petroleum. 

Steam pyrolysis is performed at temperatures higher than most other ethylene processes creating more coking potential. Process requires two separate water quench exchangers. 

Handles feeds ranging from gases to liquid hydrocarbons. Process is characterized by a highly selective pyrolysis coil. Steam pyrolysis temperature not as high as the Kellogg process reducing... 

Taralas, C. (199S) Catalytic Steam Pyrolysis of a Seleaed Saturated Hydrocarbon on Calcined Mineral Particles. Can. J. Chem. Eng., 76, 1093 ... 

Daifullah. A.A.M., Yakout, S.M. and Elreefy, S.A., Adsorption of fluoride in aqueous solutions using KMn04-modified activated carbon derived from steam pyrolysis of rice straw. J. Hazardous Mater, 147, 633, 2007. 

Dickson, P. F. Yesavage, V. F. "The Utilization of Shale Oil as a Feedstock for Steam Pyrolysis and Petrochemical Intermediate Production," Quarterly Progress Report,... 

Sagehashi, M., Nomura, T., Shishido, H., Sakoda, A. (2007). Separation of phenols and furfural by pervaporation and reverse osmosis membranes from biomass — superheated steam pyrolysis-derived aqueous solution. Bioresource Technology, 98, 2018—2026. 

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