Process for increasing the efficiency of heat removal from a fischer-tropsch slurry reactor

A cooling system for removing heat from a Fischer-Tropsch (F-T) slurry reactor, comprising:

• at least one downcomer having an upper portion and a lower portion;
• the at least one downcomer disposed within the F-T reactor to deliver a coolant downward through the F-T reactor, the at least one downcomer extending a length within the F-T reactor wherein the coolant is introduced into the upper portion of the at least one downcomer in a substantially liquid phase;
• a plenum connected to the lower portion of the at least one downcomer;
• the plenum in fluid communication with the at least one downcomer wherein the coolant remains in the substantially liquid phase;
• at least one riser having a length and extending upward from the plenum;
• the at least one riser in fluid communication with the plenum wherein a portion of the coolant vaporizes as the coolant travels along the length of the at least one riser, the at least one downcomer, the plenum, and the at least one riser defining a flow path by which the coolant travels through the F-T reactor;
• and
• a restrictor having a first side and a second side, the restrictor positioned in a predetermined portion of the flow path to generate backpressure of the coolant on the first side of the restrictor to maintain the coolant on the first side of the restrictor in the substantially liquid phase wherein a portion of the coolant on the second side of the restrictor vaporizes to provide a boiling heat transfer surface on the at least one riser.

A process of removing heat from a Fischer-Tropsch (F-T) slurry reactor, comprising the steps of:

• introducing a coolant into at least one downcomer at a pressure whereby the coolant is in a substantially liquid phase, the at least one downcomer having an upper portion, a lower portion, and a diameter disposed within the F-T reactor to deliver the coolant downward through the F-T reactor at a predetermined velocity, the at least one downcomer extending a length within the F-T reactor, the diameter of the at least one downcomer and the pressure of the introduced coolant cooperate to increase the coolant velocity thereby generating backpressure in the at least one downcomer to maintain the coolant in the substantially liquid phase along the length of the at least one downcomer;
• forcing the coolant into a plenum connected to the lower portion of the at least one downcomer;
• the plenum in fluid communication with the at least one downcomer wherein the coolant remains in the substantially liquid phase;
• and
• forcing the coolant into at least one riser having a length and extending upward from the plenum;
• the at least one riser in fluid communication with the plenum wherein a portion of the coolant vaporizes along the length of the at least one riser to provide a boiling heat transfer surface on the at least one riser.

A method of removing heat from a Fischer-Tropsch (F-T) slurry reactor, comprising the steps of:

• introducing a coolant in a substantially liquid phase into at least one downcomer having an upper portion and a lower portion, the at least one downcomer disposed within the F-T reactor to deliver the coolant downward through the F-T reactor, the at least one downcomer extending a length within the F-T reactor wherein the coolant remains in the substantially liquid phase along the length of the at least one downcomer;
• forcing the coolant into a plenum connected to the lower portion of the at least one downcomer;
• the plenum in fluid communication with the at least one downcomer wherein the coolant remains in the substantially liquid phase;
• and
• forcing the coolant into at least one riser having a length and extending upward from the plenum;
• the at least one riser in fluid communication with the plenum wherein a portion of the coolant vaporizes along the length of the at least one riser, the at least one downcomer, the plenum, the at least one riser cooperating to define a flow path by which the coolant travels through the F-T reactor, the flow path having a restrictor positioned in a predetermined portion of the flow path, the restrictor having a first side and a second side to maintain the coolant on the first side of the restrictor in the substantially liquid phase wherein a portion of the coolant on the second side of the restrictor vaporizes to provide a boiling heat transfer surface on the at least one riser.