Steam cracking process

Table 10.13 provides some characteristic data relative to the steam cracking process. 

ElexibiHty allows the operator to pick and choose the most attractive feedstock available at a given point in time. The steam-cracking process produces not only ethylene, but other products as weU, such as propylene, butadiene, butylenes (a mixture of monounsaturated C-4 hydrocarbons), aromatics, etc. With ethane feedstock, only minimal quantities of other products ate produced. As the feedstocks become heavier (ie, as measured by higher molecular weights and boiling points), increasing quantities of other products are produced. The values of these other coproduced products affect the economic attractiveness and hence the choice of feedstock. 

The feedstocks used ia the production of petroleum resias are obtaiaed mainly from the low pressure vapor-phase cracking (steam cracking) and subsequent fractionation of petroleum distillates ranging from light naphthas to gas oil fractions, which typically boil ia the 20—450°C range (16). Obtaiaed from this process are feedstreams composed of atiphatic, aromatic, and cycloatiphatic olefins and diolefins, which are subsequently polymerized to yield resias of various compositioas and physical properties. Typically, feedstocks are divided iato atiphatic, cycloatiphatic, and aromatic streams. Table 2 illustrates the predominant olefinic hydrocarbons obtained from steam cracking processes for petroleum resia synthesis (18). 

Cycloaliphatic Diene CPD—DCPD. Cycloatiphatic diene-based hydrocarbon resias are typically produced from the thermal or catalytic polymerization of cyclopeatadieae (CPD) and dicyclopentadiene (DCPD). Upon controlled heating, CPD may be dimerized to DCPD or cracked back to the monomer. The heat of cracking for DCPD is 24.6 kJ / mol (5.88 kcal/mol). In steam cracking processes, CPD is removed from C-5 and... 

Koszman, I., Antifoulant Additive for Steam-Cracking Process, U.S. Patent 3,531,394, Sept. 29, 1970. Hochman, R. F, Fundamentals of the Metal Dusting Reaction, Proceedings, Fourth International Congress on Metallic Corrosion, NACF (1971). 

Separation of raw feedstock. The pyrolysis of petroleum feedstream is carried out at 650-900°C at normal pressure in the presence of steam. The so-called steam-cracking process involves carbon-carbon splitting of saturated, unsaturated and aromatic molecules. The following steam-cracker fractions are used as raw materials to produce hydrocarbon resins. 

Chemicals directly based on propane are few, although as mentioned, propane and LPG are important feedstocks for the production of olefins. Chapter 6 discusses a new process recently developed for the dehydrogenation of propane to propylene for petrochemical use. Propylene has always been obtained as a coproduct with ethylene from steam cracking processes. Chapter 6 also discusses the production of aromatics from LPG through the Cyclar process. ... 

The main source for ethane is natural gas liquids. Approximately 40% of the available ethane is recovered for chemical use. The only large consumer of ethane is the steam cracking process for ethylene production. 

A major use of propane recovered from natural gas is the production of light olefins by steam cracking processes. However, more chemicals can be obtained directly from propane by reaction with other reagents than from ethane. This may be attributed to the relatively higher reactivity of propane than ethane due to presence of two secondary hydrogens, which are easily substituted. 

The three isomers constituting n-hutenes are 1-hutene, cis-2-hutene, and trans-2-hutene. This gas mixture is usually obtained from the olefinic C4 fraction of catalytic cracking and steam cracking processes after separation of isobutene (Chapter 2). The mixture of isomers may be used directly for reactions that are common for the three isomers and produce the same intermediates and hence the same products. Alternatively, the mixture may be separated into two streams, one constituted of 1-butene and the other of cis-and trans-2-butene mixture. Each stream produces specific chemicals. Approximately 70% of 1-butene is used as a comonomer with ethylene to produce linear low-density polyethylene (LLDPE). Another use of 1-butene is for the synthesis of butylene oxide. The rest is used with the 2-butenes to produce other chemicals. n-Butene could also be isomerized to isobutene. ... 

Crude oil processing is mainly aimed towards the production of fuels, so only a small fraction of the products is used for the synthesis of olefins and aromatics. In Chapter 3, the different crude oil processes are reviewed with special emphasis on those conversion techniques employed for the dual purpose of obtaining fuels as well as olefmic and aromatic base stocks. Included also in this chapter, are the steam cracking processes geared specially for producing olefins and diolefms. 

Raw materials for obtaining benzene, which is needed for the production of alkylbenzenes, are pyrolysis gasoline, a byproduct of the ethylene production in the steam cracking process, and coke oven gas. Reforming gasoline contains only small amounts of benzene. Large amounts of benzene are further produced by hydrodealkylation of toluene, a surplus product in industry. 

PYROCAT A steam cracking process for converting petroleum into light olefins in which a catalyst is deposited on the walls of the heat-exchanger coils in the cracking furnace. The... 

CPP [Catalytic Pyrolysis Process] A Hybrid DCC-steam cracking process, developed by Stone and Webster and piloted in China. 

PYROCAT A steam cracking process for converting petroleum into light olefins in which a catalyst is deposited on the walls of the heat-exchanger coils in the cracking furnace. The catalyst is a proprietary promoter on an alumina-calcia base. Based on the THERMOCAT process, PYROCAT was developed jointly by Veba Oel and Linde from 1996 but has not yet been commercialized. 

The furnaces obviously constitute the essential equipment of die hot section of the steam-cracking process, and they condition the satisfactory running of the overall installation. However, their optimal operating conditions and the netibility of the process to operating parameters can often only be evaluated on the ccmpletion of full-scale experiments on a pilot furnace. 

PRODL CnON OF ACETYLENE AS A BY ODUCT OF THE M. NUFACm RE OF ETHYLENE BY THE KuREHA CRUDE OtL STEAM CRACKING PROCESS. ECONOMIC DATA. . 

In quite a different application, a novel approach for producing olefins via a hydrocarbon-steam cracking process, without the use of a catalyst, was demonstrated to benefit from the use of a honeycomb monolithic catalytic reactor [28]. A typical problem associated with cracking processes of this type is maintaining the appropriate combination of heat transfer and residence time, which, if not balanced, will lead to either poor conversion... 

As previously discussed, alkyl radicals decomposition reactions constitute an important fate and reaction path of alkyl radicals. Due to the very short lifetimes of alkyl radicals, Rice and Herzfeld (1933, 1934) suggested a complete decomposition mechanism where all the radicals larger than methyl were considered instantaneously decomposed into alkenes and H and CH3 radicals. In this mechanism, all the intermediate alkyl radicals decompose to directly form alkenes and smaller alkyl radicals. This would mean that the final ethylene production from a steam cracking process would be significantly overestimated when compared with the experimental measurements. For instance, the net and final result of the successive decomposition mechanism of 1-decyl radical would be 5 moles of ethylene and one H radical. 

Finally, it is relevant to observe that this dissolution presents strong analogies with a condensation process discussed and stressed by several authors (Cai et al., 2002) as being responsible for coke formation/deposition in the TLE tube outlet section at operating temperatures of 350 450°C. Indeed this mechanism can be explained on the basis of the solubility of heavy species of the process fluid phase in the soft polymer. There has also been research into the computer generation of a network of elementary steps for coke formation during steam cracking process (Wauters and Marin, 2002). 

This chapter presents the industrial applications and validations of certain detailed models which refer to the kinetics analysed earlier. The steam cracking process will be analysed first followed by visbreaking and delayed coking processes. Last of all, the method will be applied to the thermal degradation of plastic waste. 

PkoDI-CTTO.V OF ACETYLENE AS a BY-WtODUCT OF THE MANT-TACTVTJRE OF ETHYLENE - BY THE K Li REHA CRUDE OIL STEAM CRACKING PROCESS ECONOMIC DATA -... 

---