Cooling method of hydrotreating plant and cooling unit therefor

A method of cooling a hydrotreating plant during shutdown operation, the hydrotreating plant having a desulfurization section including a furnace having at least one burner for heating a 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 a fluid from the hydrogen sulfide absorber toward the reactor, the method comprising the steps of:

• after stopping supply of the liquid to be processed, depressurizing the hydrotreating plant at the desulfurization section to a pressure level at which reactor material does not embrittle and gas does not leak due to difference of mechanical thermal expansion values in the plant;
• operating the compressor approximately at the maximum rotational speed thereof;
• and
• completely extinguishing said burner in the furnace;
• wherein
• the furnace further comprises an air inlet having an adjustable opening and a fan for introducing air into or exhausting air from the furnace;
• and
• said method further comprises, after the step of completely extinguishing the burner in the furnace, maximizing a size of the opening of the air inlet and driving the fan approximately at the maximum rotational speed thereof.

A method of cooling a hydrotreating plant during shutdown operation, the hydrotreating plant having a desulfurization section including a furnace having at least one burner for heating a 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 a fluid from the hydrogen sulfide absorber toward the reactor, the method comprising the steps of:

• after stopping supply of the liquid to be processed, depressurizing the hydrotreating plant at the desulfurization section to a pressure level at which reactor material does not embrittle and gas does not leak due to difference of mechanical thermal expansion values in the plant;
• operating the compressor approximately at the maximum rotational speed thereof;
• and
• completely extinguishing said at least one burner in the furnace;
• wherein
• the desulfurization section further has multiple air-cooling heat exchangers positioned downstream of the reactor, each of said air-cooling heat exchangers comprising an adjustable air opening;
• and
• said method further comprises driving all of said air-cooling heat exchangers and fully opening the air openings of said air-cooling heat exchangers simultaneously.