Using the numbers supplied on the Dakota Synfuels website, using the assumption stated above, the gas/C02 ratio is approximately 0.74 standard cubic feet of natural gas per cubic foot of carbon dioxide. This presumably does not account for process boiler emissions of C02 nor for C02 emissions by electricity suppliers to the plant. Looked at this way, natural gas is really the "co-product" and C02 is the principal output material.
We're wondering if other co-products, like the ones listed below, from the Dakota Gasification plant website, would also be produced by some of the newly proposed "clean coal" facilities being touted by the USDOE?
33 million pounds of "Phenol" per year [from the Dakota Gasification Material Safety Data Sheet (MSDS): "Phenol is a combustible, highly corrosive chemical that can cause serious burns and systemic poisoning by all exposure routes."]
Seven million gallons a year of "Caustic Washed Naptha" [From MSDS: "41% benzene"]
33 million pounds per year of "Cresylic Acid" [From MSDS: "This material has a strong corrosive effect on the skin and eyes. The material can rapidly absorb through the skin and may cause death".]
Footnote: if the commodity chemical co-products of natural gas were not produced, some portion would be thermally destroyed, upping the C02 production further; and some would go into increasing the overall natural gas yield.
Let's not forget that once you have "natural gas" there are processes available to convert it to liquid diesel- or gasoline-type fuel. To which you can add the naptha syngas co-product. Gasoline already contains benzene so that's a logical use. What's that you say? " EPA has been studying the feasibility of requiring a lower benzene content of fuel". Why whatever for?
Back to our post title. The only bad thing about a biogas plant is that they're not profitable in the real world. They only exist if the government subsidizes them. And the operators won't be able to pay their loans back on time. Plus, they won't have all those dandy byproducts to help recoup the investment. So you, Dear Reader, can easily see why Clean Coal is the way to go.