Process for separating liquids from fine grained solids

Claim 1

In a process of separating fine solids from oil in which the solids are dispersed, wherein said oil is mixed in a mixing zone with a solvent, transferring the resultant mixture in a separation zone, settling the fine solids below a remaining fluid phase, withdrawing the settled fine solids from said separation zone and feeding the fluid phase into a regeneration zone, in said regeneration zone subjecting said fluid phase to an increase in temperature and/or a reduction of pressure to separate out a first phase rich in oil and a second phase, withdrawing the first phase and recycling the second phase to said mixing zone, the improvement wherein the solvent comprises a first agent and a second agent, the first agent is at least one entraining agent selected from the group consisting of benzene, toluene, methanol, ethanol, an aliphatic ketone, a mixture of hydrocarbons having a boiling range of 20° to 100° C., a mixture of hydrocarbons having a boiling range of 100° to 150° C. and a mixture of hydrocarbons having a boiling range of 150° to 200° C., the second agent is at least one gas selected from the group consisting of carbon dioxide, nitrogen, hydrogen, carbon monoxide, ammonia, methane, ethane, ethylene, propane and butane, the gas being compressed and in super-critical condition wherein the gas is at a temperature above the critical temperature and at a pressure above critical pressure, said mixture of oil, super-critical gas and entraining agent containing 10 to 40 percent by weight of said first agent and 20 to 55 percent by weight of said second agent, maintaining the mixture of oil, super-critical gas and entraining agent at a temperature and a pressure above the critical state where said mixture of oil, super-critical gas and entraining agent constitutes a single fluid phase in the separation zone, segregating in the regenerating zone the fluid phase into a liquid phase and a gas phase containing at least one of the agents and subjecting the recycled gas and the entraining agent to conditions of pressure and temperature in order to reconstitute the super-critical condition.