Propylene oxide-styrene co-production method
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The propylene oxide-styrene (abbreviated as PO/SM) co-production method, also known as the co-oxidation method, was developed by Halcon Company and saw industrial production for the first time in Spain in 1973. The specific process of the co-oxidation method is as follows: at 130–160°C and 0.3–0.5 MPa, ethylbenzene is first oxidized using oxygen in a liquid-phase reactor to produce ethylbenzene peroxide. This peroxide is then concentrated to 17% concentration before being fed into the epoxidation step, where it reacts with propylene at a reaction temperature of 110°C and a pressure of 4.05 MPa to yield propylene oxide and methyl benzylic alcohol. Propylene oxide is obtained by distilling the epoxidation reaction mixture, while styrene is produced by the dehydration of methylbenzyl alcohol at 260°C and at normal pressure. The mass ratio of styrene to propylene oxide in the reaction product is 2.5:1. Apart from the ethylbenzene dehydrogenation method, this is currently the only industrial method for large-scale production of styrene, accounting for about 10% of the world’s total styrene production capacity. The characteristic of the PO/SM co-production method is that it does not require high-temperature reactions, allowing for the simultaneous co-production of styrene and propylene oxide, two important organic chemical products. By combining the endothermic reaction of ethylbenzene dehydrogenation with the exothermic reaction of propylene oxidation, energy is saved, and the problem of waste treatment in propylene oxide production is resolved. Furthermore, since the investment cost for integrated production plants is 25% lower than that for separate propylene oxide and styrene plants, and the operating costs are reduced by more than 50%, this approach offers a greater competitive advantage when constructing large-scale production facilities. The drawback of this method is that it is highly affected by the market conditions of coproducts, exhibits complex behavior, generates numerous by-products, and requires large investments; moreover, the consumption of ethylbenzene as well as the energy consumption of the facility are higher than those in the ethylbenzene dehydrogenation process. However, from the perspective of co-oxidation for propylene oxide production, it still holds great development potential as it can avoid the environmental pollution caused by the chlorohydrin method.
The introduction could be more detailed. Such excellent technology should be made known to and accepted by more people.
This post was last edited by Dongfang Shikong on 2010-6-16 at 21:54. I agree with the views expressed above, and I also hope to learn more about linked production. It is known that several large domestic petrochemical companies have co-production units in their integrated refining and chemical processing facilities. I hope experts in the petrochemical industry will kindly share their insights. h
This post also discusses the co-production of PO/SM; you might want to take a look! http://bbs.hcbbs.com/thread-288186-1-1.html
The domestic PO market needs to be expanded; currently, most PO is produced using the chlorohydrin method, and the production volume is not very high. In China, only CNOOC Shell and Zhenhai Refining & Chemical are currently operating POSM co-production units, but this technology is not very new – it has been around for 20 years and continues to be improved. Currently, this technology is a Lyondell patent in the United States, with a total of 12 units worldwide, including those at Zhenhai Refining & Chemical. Shell and LyondellBasell both use POSM co-production, but their technologies differ slightly. . It has been learned that the POSM unit at Zhenhai Refining & Chemical has successfully started up after being fed with materials.
Could you introduce the co-oxidation process technology for isobutane and propylene?
I look forward to more in-depth discussions, as well as more contributions from those who are involved in providing feedback. PO and SM co-production is indeed a great technology; everyone should exchange ideas more often to improve together
I look forward to more in-depth discussions, as well as more contributions from those who are involved in providing feedback. PO and SM co-production is indeed a great technology; everyone should exchange ideas more often to improve together
Co-oxidation of isobutane and propylene is also an excellent process route. C4 is hydrogenated and isomerized to produce isobutane; isobutane is then oxidized with air to yield isobutyl hydroperoxide, which undergoes co-oxidation with propylene to produce isobutanol + propylene oxide. Isobutanol is dehydrated to isobutylene; +MeOH yields MTBE. Both are highly valuable products. The oxidation of isobutane is a complicated process; reactions at low temperatures (0–10 degrees) yield better results with high selectivity, but the cost is higher. The reaction takes place at room temperature, resulting in high material consumption.
The two main processes for co-production in France are POSM and PO/MTBE; POSM is produced by Shell in China and LyondellBasell in Zhenhai, while the PO/MTBE projects are still under construction, with companies such as Yantai Wanhua and Nanjing involved
PO/MTBE: Isobutane is oxidized to produce TBHP and TBA; propylene is recovered via flashing to increase the TBHP concentration. TBHP then oxidizes propylene to yield TBA and PO. TBA reacts with methanol to produce MTBE downstream