By David Myers, Greg Funk and Bipin Vora
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In North America, shale gas and shale gas liquids are reviving the petrochemical industry, while at the same time lowering energy prices and improving overall refinery margins for North American refiners. Shale gas provides refiners with opportunities for diversification of feedstock and product and capitalizes on the financial benefits this diversification brings through market cycles. Shale gas also introduces new potential business models for projects, including joint ventures between refining and petrochemical companies or joint ventures between regional independent refiners. Technology innovations and the availability of lower-cost raw materials have played a major part in shaping the petrochemical industry. For example, and in the case for most modern petrochemical products, North America, Western Europe and Japan led the production of methanol from the 1960s to the 1980s. However, due to the increasing discovery of large gas reserves in places like the Middle East, Trinidad, Tobago, Chile, and Venezuela, and resultant-increased natural gas production, methanol production shifted from these industrial-consuming nations to sources of more affordable natural gas. The increased oil and gas production in the Middle East provided an abundant supply of ethane from the associated gas recovery. As a result, throughout the last two decades, a large portion of the growth in ethylene production was in the Middle East via ethane cracking. Because of this, there had been little growth in North American ethylene production in the same period. In fact, several smaller crackers were shut down. Now, with the discovery and development of shale gas and abundant cost advantaged ethane, North America is where we see the greatest potential growth.
Estimates of known natural gas reserves are increasing as new discoveries of unconventional gas reserves increase. The U.S. in particular has increased natural gas production substantially by increasing shale gas development over the last five years. This increased production has made natural gas more affordable in the U.S., benefitting the refining, petrochemical and mid-stream industries through low cost energy. Natural gas, in terms of its energy content, is significantly cost advantaged relative to crude oil. In the U.S., not only has natural gas production increased, but the production of natural gas liquids (NGLs) have increased – namely ethane, propane and butane.
After more than two decades of minimal activity, the availability of ethane and propane from NGLs at a cost effective price has revived the olefins industry. A number of new ethane cracker projects and propane dehydrogenation projects are moving forward. What does all this mean for the refiners in North America? How can they take advantage of this natural gas and NGLs boom?
Opportunities from Shale Gas Monetization - Methane
Abundant methane and associated low natural gas prices are two key factors that make the perfect environment for a gas-to-olefins (GTO) play in North America based on methanol conversion to olefins – ethylene and propylene. Methanol-to-olefins (MTO), though new to the North American market, is already a reality in China and has been since 2010.
End-products of transportation fuels versus light olefins pose fewer logistical issues for product distribution or handling, UOP believes that a pathway from shale gas to olefins (or coal to olefins) provides a route with significantly higher profitability. The first step in a coal to liquid (CTL), gas to liquid (GTL), Methanol-to-Gasoline (MTG) or MTO process is conversion of coal or natural gas to synthesis gas. For CTL and GTL the second step is conversion of synthesis gas to liquids via Fischer-Tropsch (FT) technology. For MTG or MTO, the second step is conversion of synthesis gas to methanol followed by gasoline production in the MTG process or the production of light olefins via the MTO process.
Opportunities from Shale Gas Monetization - Propane
In 1990, there were two primary sources of propylene able to meet the worldwide demand: steam crackers for ethylene production using propane and heavier feedstocks and refinery FCC units. Both primary propylene production sources at that time were from byproduct production and not on-purpose propylene production. With substantial ethane-based ethylene production in North America and the Middle East, the growth in propylene from steam crackers has not kept pace with propylene demand. While some refiners have decided to operate their FCC units in a high severity mode to increase the production of propylene, declining gasoline demand in Europe and North America has limited the overall growth in propylene production from refineries. These trends have created a gap between propylene demand and the supply from conventional sources.
This gap promises to further widen as steam cracker feed stocks continue to shift to cheaper ethane. Demand and corresponding production of propylene is increasing significantly, production from conventional naphtha cracker and refinery sources can not keep pace with demand growth, and now there is a need for on-purpose propylene production technologies, such as methanol to olefins (MTO) and propane dehydrogenation (PDH) to fill the “propylene gap.”
The figure shows the yield of propylene from different processes (steam cracking, FCC, High Severity FCC, PDH and MTO) using different raw materials. As shown, propane dehydrogenation (PDH) provides the highest yield of propylene. This, combined with low capital intensity ($/MT light olefin), has led to wide market interest in PDH in the past several years.
Yields of Various Propylene Production Processes
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Opportunities from Shale Gas Monetization - Butane
Butanes are also coming on to the market as a result of shale gas development in North America. Cost-advantaged butanes can provide opportunities for refiners to diversify feedstock while making similar products to those they make today, namely gasoline blending stocks.
The Oleflex dehydrogenation unit can be easily integrated with downstream conversion processes, such as alkylation, to produce high octane alkylate, etherification to produce MTBE or ETBE for the export market, or dimerization of isobutene followed by hydrogenation to produce high octane isooctane. The hydrogen from the dehydrogenation can be used to hydrogenate isooctene to isooctane, a high octane gasoline blending component. The UOP process for this combination is the UOP Indirect Alkylation (InAlkTM) Process.
A renewed interest in isobutane dehydrogenation has re-surfaced in the last two years, mainly centered in Asia. In addition to gasoline blendstock production, there has been interest in isobutylene production for high-purity isobutylene via MTBE cracking as well as isoprene production.
In 2012, UOP began to see interest in isobutane dehydrogenation again in North America. Dehydrogenation and subsequent upgrading of stranded butanes to alkylate or ethers for domestic use or export use presents an interesting alternative for stranded butanes.
Summary
Shale gas in North America is reviving the petrochemical industry due to the abundance of low cost NGL ethane. After almost two decades of very little activity, a number of new ethylene projects based on ethane are moving forward and several projects are under consideration for conversion of shale gas methane to gasoline and other transportation fuels via MTG and GTL. Multiple PDH projects have been announced in North America predominantly by mid-stream and petrochemical producers.
The time for diversification to enable un-matched operating flexibility in the North American refining industry is now. To learn more opportunities from shale gas monetization, visit uop.com.