Methane, coal and biomass are being considered as alternatives to crude oil for the production of basic petrochemicals, such as light olefins. This paper is a study on the production costs of 24 process routes utilizing these primary energy sources. A wide range of projected energy prices in 2030-2050 found in the open literature is used. The basis for comparison is the production cost per t of high value chemicals (HVCs or light olefin-value equivalent). A Monte Carlo method was used to estimate the ranking of production costs of all 24 routes with 10,000 trials of varying energy prices and CO₂ emissions costs (assumed to be within $0-100/t CO₂; the total CO₂ emissions, or cradle-to-grave CO₂ emissions, were considered). High energy prices in the first three quarter of 2008 were tested separately. The main findings are:•Production costs: while the production costs of crude oil- and natural gas-based routes are within $500-900/t HVCs, those of coal- and biomass-based routes are mostly within $400-800/t HVCs. Production costs of coal- and biomass-based routes are in general quite similar while in some cases the difference is significant. Among the top seven most expensive routes, six are oil- and gas-based routes. Among the top seven least expensive routes, six are coal and biomass routes.•CO₂ emissions costs: the effect of CO₂ emissions costs was found to be strong on the coal-based routes and also quite significant on the biomass-based routes. However, the effect on oil- and gas-based routes is found to be small or relatively moderate.•Energy prices in 2008: most of the coal-based routes and biomass-based routes (particularly sugar cane) still have much lower production costs than the oil- and gas-based routes (even if international freight costs are included). To ensure the reduction of CO₂ emissions in the long-term, we suggest that policies for the petrochemicals industry focus on stimulating the use of biomass as well as carbon capture and storage features for coal-based routes.

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While most olefins (e.g., ethylene and propylene) are currently produced through steam cracking routes, they can also possibly be produced from natural gas (i.e., methane) via methanol and oxidative coupling routes. We reviewed recent data in the literature and then compared the energy use, CO₂ emissions and production costs of methane-based routes with those of steam cracking routes. We found that methane-based routes use more than twice as much process energy than state-of-the-art steam cracking routes do (the energy content of products is excluded). The methane-based routes can be economically attractive in remote, gas-rich regions where natural gas is available at low prices. The development of liquefied natural gas (LNG) may increase the prices of natural gas in these locations. Oxidative coupling routes are currently still immature due to low ethylene yields and other problems. While several possibilities for energy efficiency improvement do exist, none of the natural gas-based routes is likely to become more energy efficient or to lead to less CO₂ emissions than steam cracking routes do.

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Steam cracking for the production of light olefins, such as ethylene and propylene, is the single most energy-consuming process in the chemical industry. This paper reviews conventional steam cracking and innovative olefin technologies in terms of energy efficiency. It is found that the pyrolysis section of a naphtha steam cracker alone consumes approximately 65% of the total process energy and approximately 75% of the total exergy loss. A family portrait of olefin technologies by feedstocks is drawn to search for alternatives. An overview of state-of-the-art naphtha cracking technologies shows that approximately 20% savings on the current average process energy use are possible. Advanced naphtha cracking technologies in the pyrolysis section, such as advanced coil and furnace materials, could together lead to up to approximately 20% savings on the process energy use by state-of-the-art technologies. Improvements in the compression and separation sections could together lead to up to approximately 15% savings. Alternative processes, i.e. catalytic olefin technologies, can save up to approximately 20%.

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Steam cracking for the production of light olefins (e.g. ethylene and propylene) is the single most energy consuming process in the chemical industry. Production of light olefins from natural gas is possible through different routes. This paper compares the cumulative energy use and CO2 emissions of some of these routes (methanol-to-olefins, methanol-to-propylene and oxidative coupling of methane via ethane) with those of naphtha and ethane-based steam cracking. One conclusion is that the most efficient natural gas-to-olefms-via-methanol uses more than twice as much primary energy as state-of-the-art steam cracking to produce one ton of high value chemicals. This is largely due to high energy use in methanol production. Another conclusion is oxidative coupling of methane via ethane routes could have low CO2 emissions if more recycling is used and less electricity is co-generated.@en