Propane: Sulfur's Role in the Hidden History

 Last week we gave the outline of the hidden history of the transformation of the ASTM standards. This week we briefly recount the role of sulfur in the emergence of slop as a home-heat hydrocarbon. In 1971, the first U.S. E.P.A. rules for sulfur emissions was brought out. In response to the rules, refineries brought Flue Gas Desulfurization units on-line to capture the sulfur. Their compliance with the new rules had over time two unintended consequences: 1.) agricultural land, that had obtained "free sulfur" from smokestack emissions, now experienced sulfur depletion as a result of the constant working of the soil, and 2.) the flue gases that remained were possible to transport, since the corrosive sulfur was taken out. The refining industry, never one to miss opportunity, seized the opportunities that arose from both these circumstances - it began to aggressively to market sulfur as a fertilizer, and to offer the recaptured flue gases as hydrocarbon fuel. The second opportunity is of most importance to you as a home owner who uses propane for heating and cooking.

        Since 1971, increasing volumes of recaptured flue gases, so-called "slop" has been marketed as propane, taking advantage of the ASTM definition of "commercial grade" propane that has stood since 1961. By 1975, when "special duty" equivalent to HD5 was introduced into the standard, it was apparent that "commercial grade" propane was on its way to becoming not a natural gas-processing product, but a bonus profit source for the refineries that did not have to show a speck of propane in what they sold, so long as it held a flame. As we reported last week, by 2010, half of the fuel marketed as propane was desulfurized oil refinring "odds and ends" captured at the top of the refining column and sold as fuel.  Because it consists of benzenes, toluenes, Agent Orange and other assorted poisons, it should never be used for except with the most stringent safety precautions, never for home heat. But it has, which leaves you with one best and only choice: pure olefin-free HD5 propane exclusively from Thrifty Propane.

           Next week: the ASTM standard since 1975.