Coal slurry

In practice, the separation is significantly costly due to the large amounts of water needed and wastewater generated by the process.

As blackwater cannot be purified by a water treatment plant,[9] it is stored in large impoundment ponds.

[10] Coal slurry can contain hazardous chemicals such as arsenic and mercury and can kill aquatic wildlife, as was the case in the Martin County spill.

To date, coal slurry fuels are recognised to have low energy density and therefore can only be successfully combusted in high compression engines such as diesel or gas turbine power plants (large engines with low energy density requirements).

[14] Other applications found for these slurries are in systems such as boilers, gasifiers and stationary engines with specific requirements divided into two main areas: chemical and physical as shown in table below.

A 2014 coal slurry spill into a river at Patriot Coal, West Virginia. A straw impoundment has been created across the river to try to hold the spillage. [ 7 ]