Propene

Propene, also known as propylene or methyl ethylene, is an unsaturated organic compound having the chemical formula C 3 H 6 {displaystyle {{ce {C3H6}}}} . It has one double bond, and is the second simplest member of the alkene class of hydrocarbons. It is a colorless gas with a faint petroleum-like odor Propene, also known as propylene or methyl ethylene, is an unsaturated organic compound having the chemical formula C 3 H 6 {displaystyle {{ce {C3H6}}}} . It has one double bond, and is the second simplest member of the alkene class of hydrocarbons. It is a colorless gas with a faint petroleum-like odor Propene is a byproduct of oil refining and natural gas processing. During oil refining, ethylene, propene, and other compounds are produced as a result of cracking larger hydrocarbons. A major source of propene is naphtha cracking intended to produce ethylene, but it also results from refinery cracking producing other products. Propene can be separated by fractional distillation from hydrocarbon mixtures obtained from cracking and other refining processes; refinery-grade propene is about 50 to 70%. A shift to lighter steam cracker feedstocks with relatively lower propene yields and reduced motor gasoline demand in certain areas has reduced propene supply. In the Phillips Triolefin or Olefin conversion technology propylene is interconverted with ethylene and 2-butenes. Rhenium and molybdenum catalysts are used: The technology is founded on an olefin metathesis reaction discovered at Phillips Petroleum Company. Propene yields of about 90 wt% are achieved. Related is the Methanol-to-Olefins/Methanol-to-Propene converts synthesis gas (syngas) to methanol, and then converts the methanol to ethylene and/or propene. The process produces water as by-product. Synthesis gas is produced from the reformation of natural gas or by the steam-induced reformation of petroleum products such as naphtha, or by gasification of coal. Propane dehydrogenation (PDH) converts propane into propene and by-product hydrogen. The propene from propane yield is about 85 m%. Reaction by-products (mainly hydrogen) are usually used as fuel for the propane dehydrogenation reaction. As a result, propene tends to be the only product, unless local demand exists for hydrogen. This route is popular in regions, such as the Middle East, where there is an abundance of propane from oil/gas operations. In this region, the propane output is expected to be capable of supplying not only domestic needs, but also the demand from China, where many PDH projects are scheduled to go on stream. However, as natural gas offerings in the United States are significantly increasing due to the rising exploitation of shale gas, propane prices are decreasing. Chemical companies are already planning to establish PDH plants in the USA to take advantage of the low price raw material, obtained from shale gas. Numerous plants dedicated to propane dehydrogenation are currently under construction around the world. There are already five licensed technologies. The propane dehydrogenation process may be accomplished through different commercial technologies. The main differences between each of them concerns the catalyst employed, design of the reactor and strategies to achieve higher conversion rates. High severity fluid catalytic cracking (FCC) uses traditional FCC technology under severe conditions (higher catalyst-to-oil ratios, higher steam injection rates, higher temperatures, etc.) in order to maximize the amount of propene and other light products. A high severity FCC unit is usually fed with gas oils (paraffins) and residues, and produces about 20–25 m% propene on feedstock together with greater volumes of motor gasoline and distillate byproducts. Several companies have explored biomanufacturing using engineered enzymes. The starting materials for the fermentation could be either sugars or petrochemicals.