Converting Waste Petcoke from Oilsands Production to Methanol

The bitumen upgraders in the Fort McMurray area of Alberta and the refineries in the Edmonton area are large producers of petroleum coke (petcoke), which, historically, has had essentially zero market value in Alberta.

Petcoke, however, can be converted to methanol, which can be used as a gasoline blending component or marketed as chemical-grade material. _OGJ

OGJOnce you have converted waste petcoke and low grade sub-bituminous coal to methanol, what should you do with it? That depends upon the economic factors at that moment in time. Methanol can be used on its own as fuel or in fuel cells. Methanol can be converted to gasoline via F-T. Methanol can be blended with gasoline or used in the production of biodiesel. Etc.

The potential conversion of methanol to gasoline (MTG) deserves a few words. The first commercial MTG unit was licensed by Mobil Oil in New Zealand in 1985.1

The anticipated yield from 50,000 b/d of methanol could be 20,500 b/d gasoline (rvp 9 psia, before ethanol blending; 0.73 sp gr; RON 92, benzene 0.3 vol %). And it produces about 5,500 b/d of C3-C4 LPG.

On this basis, it is difficult to see any rationale in converting methanol to gasoline if the option of methanol-gasoline blending is available. According to information from the US Environmental Protection Agency, methanol blending into gasoline is not banned in the US.

Given the investment in MTG facilities and the shrinkage in energy content (8-9%), and energy consumed by the MTG plant, the cost of the MTG gasoline would be significantly above the cost of energy in the methanol.

In this context, it is worth adding that conversion of syngas to hydrocarbon liquids by Fischer-Tropsch synthesis is technically proven and produces high-quality diesel.2 At the same time the coproduced naphtha is very paraffinic, with an octane value of perhaps 35 to 40 and is essentially nonreformable for octane elevation. Further, no steam cracker for ethylene production in Alberta is adaptable for liquid naphtha feed. _OGJ

The infrastructure for proper treatment of wastes from Canadian oilsands production is not entirely in place. But the longer that oil prices remain relatively high, the greater the motivation for development of infrastructure such as ethylene crackers, F-T catalytic synthesis plants, and fermentation (of syngas) bioreactors for advanced chemicals and fuels. Algal and microbial bioreactors for conversion of the massive CO2 effluent to biomass, fuels, and high value chemicals should eventually come into the mix.

The CO2 produced may be used for many other purposes including EOR.

Here is a comparison of cost per gallon for various fuel liquids:

OGJNotice the high octane value and low cost of methanol -- helpful for blending with gasoline.