(char)coal slurry is a viable fuel but it needs an engine designed to use it.
"normal diesel engine" these days means common rail injection and usually there will be a turbo, a diesel particulate filter and a catalytic converter.
Here's what will happen if you run your normal diesel engine on (char)coal slurry. Your engine will stop at the first bulletpoint but let's imagine each problem is somehow solved as it is met.
- Your fuel pumps, fuel filter and injectors will become blocked, likely destroyed.
- The oil introduced thru the pressure relief will mix with soot and ash
from the EGR system to create a sludge in your intake manifold, increasing the burn temp in the cylinders.
- Your piston rings will wear quickly, causing you to lose compression and allowing burnt & unburnt fuel to mix with the engine oil.
- Incomplete burn & engine oil in the cylinders will further increase combustion temperatures.
- Unburnt fuel and engine oil will now also be getting into your intake via the EGR system
- The contaminated oil and the increased combustion temperatures will destroy your turbo sending metal pieces and more oil (and water if you have water cooled turbo) into the intake manifold and then into the engine
- The increased combustion temperatures will blow your head gasket and/or crack the head, allowing coolant water to mix with engine oil, your cooling
system will stop working and the engine will seize and be destroyed.
- The soot and ash in the exhaust will block your DPF and your catalytic converter, requiring a new exhaust system