NOVELTY - A torrefaction system comprises: at least one pool containing a liquid heat transfer agent, that provides thermal contact with biomass to heat the biomass into biocoal; and a conveyor system (52) transporting the biomass through the pool in a first direction and transporting the biocoal in a second direction opposite to the first direction in the pool.    USE - As a torrefaction system (claimed), for producing a combustible fuel, and for converting biomass into biocoal.    ADVANTAGE - The torrefaction system reduces energy consumption, while improves throughput; and improves the quality of biocoal and reduces production costs by removing and recovering the heat transfer agents from the biocoal. The oil/paraffin is used as the heat transfer agent, therefore the solvent and water pools that are used to wash off the oil and solvent remaining in the biocoal are recovered and reused. The torrefaction system provides cleaner and higher quality biocoal with minimal residual chemical agents, while ensuring a safe production process should air somehow leak into the torrefaction system.    DETAILED DESCRIPTION - A torrefaction system comprises: at least one pool containing a liquid heat transfer agent, that provides thermal contact with biomass to heat the biomass into biocoal; and a conveyor system (52) transporting the biomass through the pool in a first direction and transporting the biocoal in a second direction opposite to the first direction in the pool. The system further comprises housing (50) and bridges raised from a bottom of the housing, where the pools are divided by the bridges. The pools include at least one torrefying pool including the liquid heat transfer agent, and at least one water pool containing water. The pool further includes at least one solvent pool containing solvent, where the solvent is selected from hexane and naptha. The heat transfer agent is selected from oil, molten paraffin and molten salt.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of torrefaction unit of the production plant.    Housing (50)    Conveyor system (52)    Airlock system (54)    Water pools (70, 72)    Solvent pools (74, 76)    Torrefying rivers (78, 80)