Oxidative Hydrothermal Dissolution (OHD) is a novel coal conversion technology developed with support from the Illinois Clean Coal Institute. OHD works by reaction of coal and/or biomass with small amounts of oxygen in high temperature, high pressure, liquid water. This breaks up the coal’s structure, resulting in the generation of low molecular weight, water soluble products. Complete conversion of the coal is readily achievable with 70-90% recovery of the original carbon as water soluble products. Most silicate minerals present in the coal pass through the process essentially unaltered. Raw OHD product is an aqueous solution (not a colloid or suspension) consisting of a mixture of low-medium molecular weight aromatic and
aliphatic acids and related derivatives that could potentially supplement or replace some petroleum–derived products as chemical feed stocks. Raw OHD product can be pumped and refined using conventional liquid processing technology. Since the process uses only water and oxygen, it is inherently environmentally friendly. No
exotic solvents or expensive catalysts are required. It produces little CO2, and no NOx, SOx or other toxic emissions. Harmful elements like mercury, arsenic etc., are not released to the
environment but either remain associated with their parent minerals or are retained in the product solution and can be processed and captured by conventional waste water treatment strategies.