Palladium, Not Carbon, May Be Used To Scrub Mercury From "Clean Coal" Plants
Because there is no "away" when it comes to economically useless, toxic, heavy metals found in coal, and because most commercially used activated carbon is made from coal (which of course means that the activation of carbon emits heavy metals), we have long wondered how what the industry calls a "clean coal" syn-gas plant would perform over the full production life cycle - mine to electricity distribution - when it comes to controlling the poisonous heavies. Now comes news that something other than activated carbon could be used to scrub out the heavy metals, indicating that life cycle performance might be better than one would assume if carbon were the control technology of choice. "Johnson Matthey company... has been granted an exclusive license by the U.S. Department of Energy’s National Energy Technology Laboratory (NETL) for its high temperature sorbent technology and patent to remove mercury, arsenic and potentially selenium, cadmium and phosphorous from syngas produced by coal gasification. This license was a natural extension of a two-year Cooperative Research and Development Agreement (CRADA) between Johnson Matthey and NETL to evaluate and optimize palladium (Pd) sorbent material properties and performance. Unlike conventional sorbents such as activated carbon, which operate at ambient temperature, high temperature Pd sorbents remove mercury and arsenic at temperatures above 500°F, resulting in a major improvement in overall energy efficiency of the power combustion process."So, while this licensing development provides an insight as to how the toxic heavies might be cost-effectively removed from a publicly funded syn-gas stream, we still lack information about how the palladium-removed toxic metals will be managed in total. This leads to a key question which has never, to our knowledge, been addressed in the mainstream media. Under normal circumstances, the captured heavy metals would be regulated as hazardous waste if generated in excess of 1000 Kg/month at a US syn-gas plant. This regulatory threshold would apply as soon as that much palladium/heavy metal complex were removed from the syn-gas process for off site waste management purposes. Theoretical ways to avoid the expensive proposition of having a syn-gas plant regulated as a large quantity generator of hazardous waste would potentially include: keeping generation rate of the heavy metals under the 1000/Kg per month threshold [conditionally acceptable situation]; or, using some sort of national defense ruse to convince the US-Environmental Protection Agency to exempt the syngas metal waste stream from being regulated as a hazardous waste [bogus and lame if attempted]; or, find an economically viable market for the metals removed [best possible outcome].
Inquiring minds want to know how the clean coal industry and DOE intend for to this to go? What economically useful products might be made with the mercury, for example? Are we going to open up the decision process to the public. Because there is no away.
It has been proposed, somewhat tongue-in-cheek we suppose, that the best economic use of cadmium would be to cast public statuary to keep the metal isolated from living organisms. Unfortunately, the same would not work for mercury.
Some of the most fantastic black and white photographs ever made are palladium prints.
Palladium is a rare metal, very expensive, and subject to price fluctuations (as pictured) based in part on demand for pollution control applications such as catalytic converters. If Chinese cars are required to use Pd converters, the market competition for the metal will greatly affect the economic viability of this licensed technology.
Update: Sending the spent Palladium complex offsite for recycling might potentially provide an exemption from hazardous waste regulation. That simply transfers all the issues and question to the recycling site. Where would that be?
Via:: Power Online
Image credit: HES Radio Palladium Investor Alert