Petrochemical industry ethylene crackers

Most capacity is in Saudi Arabia, which has almost 7 million tonnes of ethylene capacity mainly using gas based feedstocl. Current capacity in Iran, Qatar and Kuwait stands at about 1 million tonnes each and the UAE has a cracker of 600,000 tonnes. Larger plants are under construction in Iran". The status of the Iraqi petrochemical industry is unknown. 

The world petrochemical industry is surveyed annually in the Oil Gas Journal as the Ethylene Report. This is a useful source of country production, individual steam crackers (including ownership) and the feedstock used. Since 2006 US olefins and the US natural gas liquid supply and prices are each reviewed twice per year by Lippe. Weissermel and Arpe have provided an excellent description of many technologies and approaches to chemical synthesis in the chemical process industry. 

T he expansion of the petrochemical industry and the accompanying increase in the demand for ethylene, propylene, and butadiene has resulted in renewed interest and research into the pyrolytic reactions of hydrocarbons. Much of this activity has involved paraffin pyrolysis for two reasons saturates make up most of any steam cracker feed and since the pioneering work of Rice 40 years ago, the basic features of paraffin cracking mechanisms have been known (1). The emergence of gas chromatography as a major analytical tool in the past 15 years has made it possible to confirm the basic utility of Rice s hypotheses (see, for example, Ref. 2). 

Slovakia. The Slovakian petrochemical industry is dominated by Slovnaft, which operates two petrochemical sites. The complex at Bratislava has a naphtha cracker, three LDPE units, two propylene plants, and an aromatics unit. Most of the ethylene produced goes to LDPE and ethylene oxide/ ethylene glycol production. Some ethylene goes to vinyl chloride monomer... 

Croatia. The Croatian petrochemical industry has been greatly affected by the breakup of Yugoslavia. Industrija Nefta owns and operates five petrochemical sites as well as three refineries. There is one small olefins cracker in Zagreb, which supplies ethylene to an adjacent complex for LDPE. The propylene produced is used as a fuel. Three construction projects were under way in the petrochemical area, one being an expansion of an existing facility, as of 1999 [13]. 

Since in the oxidation of benzene to maleic anhydride, two carbon atoms are lost as CO2, attempts were made early on to produce maleic anhydride from C4 hydrocarbons. With the development of the petrochemical industry, large quantities of C4-cuts became available, from which butene and, by hydrogenation, butane, could be recovered. The use of benzene is in decline, particularly in the USA, since benzene is now produced there, among other routes, by dealkylation of toluene, whereas C4-components are readily available from cat-cracker and ethylene plants. 

It is possible to point out a number of conclusions from this figure. Firsf of all if is understandable why much of the investment within the petrochemical industry is directed to the Middle East. The feedstock, ethane from flare gas, is cheap and a dedicafed efhane cracker requires a relatively low investineni. If is also seen that the coming investments in bioethylene in Brazil, with a production cost of approximately 800/tonne, are very competitive with the fossil-based US alternatives, having a production cost of roughly 1050/tonne. The variable cost is relatively low but compared to the Middle East ethane alternative the investment is higher due to the fermentation plant. Furthermore, it is important to point out that the investment for the ethanol-to-ethylene plant is very low as seen for ethanol-purchased alternatives. For these cases it is important to stress that these are valid for the conditions in the USA, i.e. the price level of ethanol in the USA. In Europe it is possible to get exemption from the import duty on ethanol imported from Brazil. This would lead to a variable cost of approximately 700/tonne and thus a production cost of approximately 900/tonne. 

In addition, there is one more factor that must be included. Within the EU, CO2 trading has been introduced as one of the means to reduce CO2 emissions. The petrochemical industry considers it likely that the renewal of the Kyoto protocol will result in a CO2 tax. The extra cost on the final product will then depend on the fee per unit of emission and the amount of emission per unit of product. For the examples in Figure 6.3 above this would lead to changes in the competitive situation (see Figure 6.4 [30]). The emissions for coal are large, around 5-7 kg C02/kg olefin, and for a naphtha- or ethane-based cracker about 0.5-3 kg C02/kg olefin. Green ethylene would most probably be free from this kind of tax if biomass is used as the energy source. 

Shanghai Secco Petrochemicals Co Ltd, a jv company of BP (London, UK www.bp.com), Sinopec and Shanghai Petrochemicals Corp, is building a world-scale complex at Shanghai Chemicals Industry Park in Caojing. The Secco complex, expected to begin operation in 2005, will comprise a 900 000 tpa, naphtha-fed ethylene cracker, plus downstream facilities with combined PE, PP and PS capacity of more than 1 million tpa, plus world-scale styrene, acrylonitrile and other olefins-derivative units. 

Propylene is one of the most important feedstocks for the petrochemical industry and can be used in the production of a wide variety of products such as polypropylene, acrylonitrile, cumene, oxo-alcohols, propylene oxide, acrylic acid, isopropyl alcohol, etc. (Weissermel and Arpe, 2007). Nowadays, the propylene demand is increasing faster than the ethylene demand. The expected growth of propylene with respect to ethylene exceeds the ratio obtained from steam crackers because a portion of steam crackers is now using inexpensive ethane feedstock (Bricker, 2012 Sanfilippo and Miracca, 2006). The dehydrogenation of propane (DHP) offers an option to capture the marginal, additional capacity needed to compensate for the imbalance (Buyanov and Pakhomov, 2001). A number of technologies are commercially available for the DHP to propylene for example, Oleflex, Catofin, Star, PDH, and FBD (Abdullah, 2007 Eisele and KiUpack, 2000). From 2011, several DHP plants have been planned to be built in China with the total capacity exceeding 6 miUion tons per year (Zhu, 2012). 

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