Coal liquefaction

Coal liquefaction is a process in which coal is converted into liquid fuels or petrochemicals. There are several processes used to accomplish this task, with the two most common being the indirect route and the direct route.

The indirect route is composed of 2 steps: First, coal is gasified with steam and oxygen to produce synthesis gas (syngas), which is then cleaned to remove dust, tar, and acid gases. In the second step, the cleaned synthesis gas reacts over a catalyst in the Fischer-Tropsch process, converting the syngas into a range of hydrocarbon products, including gasoline, diesel, methanol, and other liquid fuels.

In the direct route, coal is pulverized and reacted with hydrogen under high pressure and temperature in the presence of a catalyst and a solvent to produce a raw liquid fuel. This raw fuel requires further refining to produce transportation fuels that meet fuel quality specifications.

Watch the video below for a visual explanation of the coal liquefaction process. This video was created by the Biofuels Academy:

Benefits

Countries with abundant coal resources (such as the United States and China) can benefit from this conversion, as it can help reduce reliance on imported liquid fuels. It also offers the potential to produce hydrogen economically.

Carbon capture and storage can be integrated into the process, and biomass can also be incorporated to reduce the CO2 footprint while taking advantage of the economies of scale associated with coal.