Retort system

A recirculation circuit for a processing vessel configured to process a load with a process fluid, the recirculation circuit comprising:

• a first circuit portion configured to recirculate a first portion of the process fluid through the vessel, the first circuit portion comprising:
• a first pump having a first flow rate capacity and a first rated output pressure;
• a heat exchanger inlet pipe having a heat exchanger valve configured to be selectively opened for flowing process fluid in the first circuit portion to a heat exchanger;
• and
• a bypass portion pipe having a bypass valve configured to be selectively opened for flowing process fluid through the bypass portion pipe;
• a second circuit portion configured to recirculate a second portion of the process fluid through the vessel, the second circuit portion comprising:
• a second pump having a second flow rate capacity higher than the first flow rate capacity and a second rated output pressure lower than the first rated output pressure,
• wherein the first pump and the second pump continuously recirculate process fluid through the vessel;
• and
• a controller programmed in accordance with process requirements of the load, the controller including pipe circuitry for selectively opening the heat exchanger valve and the bypass valve, wherein the controller closes the heat exchanger valve and opens the bypass valve during a first phase of the thermal process, and wherein the controller opens the heat exchanger valve and closes the bypass valve during a second phase of a thermal process;
• wherein the bypass valve is throttled to substantially match a first pressure drop in the heat exchanger inlet pipe to a second pressure drop in the bypass portion pipe during the first phase of the thermal process such that the flow of process fluid in the processing vessel during the first phase substantially matches the flow of process fluid in the processing vessel during second phase.