Kentucky Liquefies Coal with Plastic

November 03, 2009

ScienceDirect - Fuel Processing Technology : Direct liquefaction of waste plastics and coliquefaction of coal-plastic mixtures

We have been informed of a conference upcoming, or even now taking place, in Kentucky which might relate to, or present some info related to, coal-to-liquid conversion technology. We'll continue our research, and try to keep you apprised.

In the meantime, herein is yet more documentation of the very real coal liquefaction developments that are, and, as we have documented, for decades have been, taking place in that state.

What is sadly lacking in all of this is attentive, public reportage that would keep programs like this on track, maintain their momentum, and prevent their being buried by special interests that have no interest in seeing our own domestic coal solve our own nation's liquid fuel shortage.

The excerpt:

"Direct liquefaction of waste plastics and coliquefaction of coal-plastic mixtures

Zhen Feng, Jianmin Zhao, Jeff Rockwell, Dan Bailey and Gerald Huffman

CFFLS, 533 South Limestone St., Room 111 University of Kentucky, Lexington, KY 40506-0043, USA

February 1999.

Abstract

We have conducted further investigations of the direct liquefaction reactions of waste plastics, medium and high density polyethylene (PE), polypropylene (PPE) and coal-plastic mixtures, varying the catalyst, temperature, gas, pressure, time and solvent. The experiments used four types of catalysts: a commercial HZSM-5 zeolite catalyst, and three catalysts synthesized in our laboratory, ferrihydrite treated with citric acid, coprecipitated Al2O3---SiO2, and a ternary ferrihydrite-Al2O3---SiO2. For direct liquefaction of plastics alone, a solid acid catalyst such as HZSM-5 or Al2O3---SiO2 markedly improves oil and total liquid yields, as determined by pentane and THF solubility, respectively. Yields are higher when using either a waste oil solvent or no solvent than using tetralin as the solvent. For PE, temperatures of 430 °C or higher are required for good yields, while PPE gives excellent yields at 420 °C. A commingled plastic provided by the American Plastics Council (APC) exhibited peak oil and total liquid yields at 445–460 °C. The oil yields and total liquid from PE (HZSM-5, 430 °C) and the APC commingled waste plastic decreased only slightly with decreasing hydrogen pressure (from 800 to 100 psig H2 (cold)). Furthermore, yields were as high under nitrogen (200–600 psig, cold) as under hydrogen.

Coliquefaction experiments were conducted on 50-50 mixtures of PE, PPE and the APC plastic with Black Thunder coal. For these experiments, the best results were obtained when the solvent was tetralin or a mixture of tetralin and waste oil. Lower yields were observed with only waste oil or with no solvent. Either HZSM-5 or Al2O3---SiO2-ferrihydrite increased oil and total yields by approximately 10% at 460 °C. Under the same conditions, yields from a PPE-coal mixture were substantially higher than those from a PE-coal mixture."

We'll note the utility of a zeolite catalyst which sounds very much like the one employed by Exxon-Mobil in their "MTG", methanol-to-gasoline, Process; wherein the methanol is posited to be made from coal.