Processes for preparing a low particulate liquid hydrocarbon product are provided and include blending a tar stream containing particles with a fluid and heating to a temperature of 250°C or greater to produce a fluid-feed mixture that contains tar, the particles, and the fluid. The fluid-feed mixture contains about 20 wt% or greater of the fluid, based on a combined weight of the tar stream and the fluid. Also, about 25 wt% to about 99 wt% of the particles in the tar stream are dissolved or decomposed when producing the fluid-feed mixture.