Device and method for optimising the circulation of a suspension in a plant comprising a three-phase reactor

A facility for chemically converting a feed, comprising:

• at least one reactor (2) containing a slurry comprising at least one suspension of at least one solid in a liquid;
• a gas supply located in the lower portion of said reactor;
• and
• a circuit (11, 12, 13), external to said reactor, for continuous circulation of a slurry stream, said circuit comprising:
• a line for withdrawing said slurry stream from at least one point (A) of said reactor,
• at least one block valve (14) on said circuit downstream of point (A) for stopping circulation of said slurry stream in said circuit,
• means for introduction of at least one pressurized fluid at at least one point (D) of said circuit, said point (D) being downstream of said block valve,
• a separation section (17), downstream of said point (D), for separating at least one fluid contained in said slurry stream traversing the external circuit,
• a line for reintroducing at least a portion of said slurry stream at at least one other point (B) of said reactor, wherein point (B) is below point (A), and
• means (16), downstream of said separation section (17) and upstream of point (B), for circulating said slurry in said external circuit from point (A) to point (B) under conditions such that the Reynolds number is more than 2500 at every point in said external circuit (11, 12, 13),
• wherein said means for introduction of at least one pressurized fluid at at least one introduction point (D) is connected to a source of at least one pressurized fluid which is substantially free of solid in suspension and is at a pressure higher than that of point (D);
• and
• a free volume (5) is provided in the upper portion of the reactor (2) above the liquid/solid suspension, said free volume being greater than the total volume of the liquid/solid suspension contained in the circuit and in the separation section (17),
• said facility further comprising means for detecting at least one operational defect in said facility connected to means (50) for obtaining automatic immediate closure of said block valve (14), when said at least one operational defect is detected, and for subsequently automatically introducing pressurized fluid substantially free of solid in suspension by opening of at least one valve (41, 42, 43) thereby placing said circuit into communication with said source of pressurized fluid which is substantially free of solid in suspension via said means for introduction of at least one pressurized fluid at at least one point (D).