Patent ID: 7112311

Claim:
A cooling unit of a hydrotreating plant having a desulfurization section including a furnace for heating liquid to be processed, a reactor for hydrotreating sulfur to generate hydrogen sulfide, a hydrogen sulfide absorber for absorbing the hydrogen sulfide generated in the reactor, and a compressor for compressing and transferring fluid from the hydrogen sulfide absorber toward the reactor, the cooling unit rapidly cooling the reactor during shutdown operation, the cooling unit comprising: a gas-releasing valve provided on the desulfurization section; an opening for the passage of air and a fan both provided on the furnace, the opening for the passage of air capable of adjusting opening size thereof and the fan introducing and exhausting the air; at least one heat exchanger for exchanging heat between fluid on the downstream side of the reactor and fluid supplied to the upstream side of the furnace; an openable and closable bypass line for bypassing the heat exchanger; and a throttling valve provided on the entrance of the heat exchanger.