The chlorohydrin method uses propylene and chlorine gas as raw materials, and goes through three steps of propylene chlorohydrinization, lime milk saponification, and product purification, and finally obtains qualified product. The chlorohydrin method was industrialized as early as 1931. It has the advantages of mature technology, short process, low requirements for raw material purity, and low investment.
However, the disadvantages of the chlorohydrin method are also very obvious: In addition to the low purity of propylene oxide, the "three wastes" produced during the production process And the corrosion problem of hypochlorous acid to equipment also needs to be improved and solved urgently.
The "Industrial Structure Regulation" promulgated as early as 2011 The whole guide catalog ( 2011 Yearbook) " clarified that the new chlorohydrin method propylene oxide will be restricted device. Among them, petrochemicals are encouraged In the chemical industry, the direct oxidation method of propylene oxide of 150,000 tons/year and above, and the co-oxidation method of 200,000 tons/year and above of propylene oxide are listed; in the restricted category, newly-built chlorohydrin method propylene oxide devices are listed, according to regulations , belonging to the scope of technology, equipment and products that are prohibited from new construction and require supervision and transformation.
2021 In the case of stricter environmental protection policies in 2010, some chlorohydrin method manufacturers were affected to a certain extent due to geographical location and local environmental protection policies, and Tianjin Dagu, Fuzhou Bay Chlor-Alkali Industrial Chlorohydrin Process Plant was permanently shut down.
As far as the current market is concerned, the chlorohydrin method is still the mainstream cyclopropane production process, accounting for 42% (based on 2021 annual report data).
As a large number of propylene oxide projects under construction in my country will gradually be put into production, the industry will be oversupplied, and the production cost of chlorine is low but the pollution problem is serious. Alcohol production of PO technology is facing phase-out, and the industry structure will face a new round of reshuffle.
In the next three years, new production capacity will be mainly based on HPPO direct oxidation and co-oxidation (PO/SM, PO/TBA). Among them, the HPPO method has a simple process, a mild reaction, and a single product; however, the industrialization time is short, and the process needs to be perfected. At present, it is difficult to achieve double high efficiency of conversion rate and selectivity. Although the co-oxidation method reduces the product cost through co-production, its equipment investment is high, and the process flow is long and complicated.
As for the exact phase-out time of the chlorohydrin method, what is the future cyclopropane production capacity and process structure? Tiantian Chemical Network will continuePlease pay attention!
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