There are two things we find interesting about this study on combining coal and waste plastics together to form a raw material for liquid fuel manufacture.
First, the inclusion of plastic actually provides at least some of the needed Hydrogen to convert the primarily carbonaceous coal into liquid hydrocarbons, as in: "The waste plastics having high H/C ratio are expected to play the role of hydrogen source".
Second, the process can be refined, especially in terms of coal-to-plastic combination ratios, so that the non-organic minerals in the coal can capture and immobilize, as various salts, the chlorine which might be present in the plastics.
Excerpt as follows:
"The Influence of PVC on the Coprocessing of Coal and Plastics
Author(s): Koyano Koji, et. al., Nihon University College of Science and Technology
Journal Title: Journal of the Japan Institute of Energy
Abstract;The coprocessing with coal is one of the beneficial technologies to convert waste plastics into alternative liquid hydrocarbon for fuel oil and chemical feedstock. The waste plastics having high H/C ratio are expected to play the role of hydrogen source. On the other hand, the waste plastics include chlorine-containing plastic such as polyvinyl chloride (PVC). Hydrogen chloride generated from pyrolysis of PVC causes the problems such as the corrosion of equipment. In the coprocessing reaction, it is expected that the hydrogen chloride is captured by the minerals in coal. In this paper, the influence of PVC on the coprocessing with Wyoming subbituminous coal and the mixture of high density polyethylene, polypropylene, polystyrene, and PVC was investigated under decalin solvent. A part of hydrogen chloride generated from PVC was fixed as chlorides by the minerals in coal, but the rest formed chlorinated organic compounds. These reactions occurred competitively. When a sufficient amount of hydrogen chloride was not captured, the chain reactions of polymer radicals were inhibited by chlorine radical. This inhibitation resulted in the increase of heavy oil yield. To avoid it, the optimization of the ratio of coal and plastics was desired."
In other words, not only can coal and waste plastics be combined to produce liquid fuels, but, the ratio of coal and plastics can be optimized, both for maximum liquid fuel output based on the hydrogen content of the plastic and for immobilization of the chlorine contained by the plastic, based on the inorganic mineral content of the coal. The two raw materials can be synergistic. Combing coal and plastics to synthesize liquid fuels can be done, and we know it can be done. People are at work on fine-tuning the process.