Preparation of Summary of chemical processes of propylene

[Abstract] With the demand for downstream products such as polypropylene rapid growth, as well as new raw materials for ethylene oxide production unit increase in the proportion of propylene supply of resources gradually showing a tension. Accordingly, the propylene production Technology products for the purpose of increasingly active Research, propylene production Technology has become the focus of the current oil refining and chemical Research direction.

[Keywords:] the production of propylene Chemical Technology

1 Definition of propylene
Propylene is mainly used for production of polypropylene, acrylonitrile, propylene oxide and isopropyl alcohol, are second only to the important petrochemical feedstock ethylene.

2 Propylene Development of Preparation Process
Propylene chemical processes currently mainly focused on four aspects: First, improve the FCC and other refinery processes, and tap the potential of existing installations, the FCC propylene plant upgrade Technology; the second is full use of by-product of oil refining and ethylene cracking of C4-8 and other resources, into ethylene, propylene, low-carbon olefin cracking technologies, olefin metathesis Technology; third is propane dehydrogenation process; Fourth, natural gas, coal and other raw materials, production of ethylene, propylene, methanol to olefins and crafts.

2.1 propylene in FCC technology
FCC unit global production capacity of about 750Mt / a, by adjusting the variety of raw materials, catalysts, conditions and operating conditions to increase the Development potential of propylene is very large, many domestic and foreign companies are active in Research in this area.

Compared with the traditional FCC, such technology is more demanding operating conditions, required reaction temperature, catalyst to oil ratio higher catalytic less time. The use of these technologies, although gasoline yield will be affected, but the olefin in gasoline decreased, the quality can be improved, than the traditional FCC propylene production 2 to 4 times higher. catalytic cracking process of oil refining industry capacity, mixed with slag is high, resulting in higher olefin content in gasoline, the FCC propylene Development and application of technology in improve the oil quality, while downstream more olefins, with good market prospects.

2.2 Propylene Olefin Cracking process technology
Olefins cracker is C4-8 olefin into the catalyst of the process of propylene and ethylene, which can not only solve the refinery and naphtha cracking by-product of the C4-8 of the way out, but also increase production of high value-added ethylene, propylene products, become more active in the areas of Research in recent years.

Olefin cracking process, from investment costs, production costs and consolidated income point of view, are the most attractive technology. Fixed bed process is relatively simple, suitable for integration with existing steam cracking; fluidized bed process is relatively complex, suitable on building large-scale production equipment, can be incorporated into olefin combination unit, you can also establish a separate unit. With China a number of large ethylene cracker expansion and new, C4 + olefins more abundant resources, the Development of independent intellectual property rights of olefin cracking technology to address the by-product of C4 + olefins, propylene yield high value-added demand urgent.

2.3 propylene olefin metathesis technology
Olefin metathesis technology has been developed many years ago, only because some areas in recent years, propylene prices gradually rise, this technology once again aroused people's attention. It is a means of olefin carbon - carbon double bonds break and re-converted into olefin products catalytic reaction, the current ethylene and 2 - butene propylene as raw materials for the production of disproportionation is more active in technology Research, there are ABB Lummus's OCT technology and high-temperature catalyst for the French Institute of Petroleum (IFP) of the Meta-4 low-temperature catalytic process.

Olefin metathesis process can be applied to naphtha steam cracker propylene, investment increased marginally, to improve the naphtha cracker in the propylene / ethylene production ratios, but the drawback is that producing 1t propylene, ethylene to be consumed 0.42t, Therefore, only the price is higher than ethylene propylene prices, excess ethylene production is Economically viable. disproportionation other technology can not be isobutylene and C5-8 olefins into propylene, subject to certain restrictions apply. In recent years the Development of auto-disproportionation technology, do not or a small amount of ethylene, the application prospect.

Links to Research Papers Download http://www.hi138.com 2.4 technology Propane Dehydrogenation to Propylene
Is strongly endothermic propane dehydrogenation process can be relatively low pressure at high temperature and a reasonable yield of propylene. Propane dehydrogenation technology has three major advantages: first, a single feed, single product (mainly propylene); Secondly, only the cost of production is closely related to propane, and propane prices and naphtha prices, the market is not directly related to propylene, propylene derivatives, which can help manufacturers improve the cost structure of raw materials, to avoid some market risk; Third, the supply for the propylene inadequate production plant derivatives, can be bought cheaper propylene oxide production, eliminating the high costs of transportation and storage expenses propylene.

Compared with other production technologies, access to the same scale production of propylene, propane dehydrogenation technology infrastructure investment is relatively low, the current Economic scale is 250kt / a. propane prices of raw materials a greater impact on production costs, only when the propylene and propane long-term average spread is greater than the minimum 200 dollars / t, the factory in order to have better profits. propane resource-rich Middle East region, price stability conducive to building a propane dehydrogenation plant. our current building does not have the propane dehydrogenation plant conditions, research in this area, as certain technical reserves.

2.5 methanol to olefins technology
Rise in crude oil prices, natural gas or coal resources are relatively rich in the case of natural gas or coal as raw materials to produce methanol, then methanol production olefin (MTO process), or methanol to propylene (MTP process) technology more and more attention. Currently there are more mature technology UOP / Hydro MTO process and the company's Lurgi MTP process.

MTO, MTP process can be used as raw materials to produce olefins from petroleum as an alternative or supplement, compared with the price of crude oil and naphtha, natural gas prices are relatively independent, so the use of raw materials MTO technology will help to improve cost structure, which for crude oil resources in the increasingly tense China is very meaningful. Compared with the naphtha or ethane cracker, when crude oil prices above 16 USD / bbl or ethane prices above $ 3 / MBtu when, MTO can provide lower production costs and higher investment return.

2.6 The latest progress of olefin production process
Propylene over the past few years made significant progress in technology, all characteristics of all these processes, but there are some shortcomings, for each other, appeared in a variety of applications of these techniques combined, led to significant improvements in process performance.

Olefin Cracking process technology combined with the naphtha steam cracking. Olefin cracking unit (such as the OCP process) can feed naphtha cracker, FCC, coking, MTO and other by-product of the C4-8 olefin mixture, and the olefins produced by cracking C4-8 steam can? ring into the pyrolysis furnace for further reaction. OCP device to produce heat and power 0.25t 1t can be ethylene propylene, when it is integrated with the construction of naphtha steam cracker, can significantly reduce investment and operating costs, reduce the C4 + vice production, productive 30% of the propylene.

MTO process and Olefin Cracking combination. MTO is characterized to produce 1t of ethylene and propylene, only output 0.2tC4 + by-products, if the increase in OCP device into a heavier olefins, ethylene and propylene yield can be increased by 20% to 85 % to 90%, propylene and ethylene production compared to 1.75, C4 + products reduced by almost 80%. by optimizing the catalyst and the MTO MTO process and Olefin Cracking the combination of propylene and ethylene ratio can reach 2.0 or more.

3 Conclusion
China's oil refining business, basically has a by-product recovery of propylene and propylene derivatives plant; refining and chemical integration of enterprises, some of the existing refinery, there are some ethylene steam cracker, as well as sets of propylene by-product processing plant, Therefore, combined application of FCC process propylene, propylene and other olefin cracking process technology, has a good application base, the future will be to focus on the development.


References:
[1] Zhu Minghui. Foreign propylene latest production technology and technical and Economic comparison [J]. International Petroleum Economics, 2006.

[2] Wang Bin. C4, C5 olefins catalyzed ethylene propylene Progress [J]. Molecular Catalysis, 2006.

[3] Sang Lei. Propylene oxidation process of [D]. Shandong University of Technology, 2007.

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