Compressor unit

A compressor unit that is a reciprocating compressor unit configured to recover hydrogen gas that is boil-off gas from a liquid hydrogen storage tank and supply at least a part of the hydrogen gas to a demand destination including at least one of an engine, a power generation facility, and a boiler, the compressor unit comprising:

• a first compression stage configured to compress hydrogen gas;
• one or two or more succeeding compression stage configured to further compress hydrogen gas discharged from the first compression stage;
• a crank mechanism configured to drive the first compression stage and the succeeding compression stage;
• a first spillback unit including a first spillback flow path and a first spillback valve, the first spillback flow path being for returning a part of hydrogen gas after being discharged from the first compression stage to a suction flow path, and the first spillback valve being for adjusting a spillback amount in the first spillback flow path;
• an adjuster for adjusting a processing amount of hydrogen gas by the succeeding compression stage;
• a pressure sensor arranged on an intermediate flow path between the first compression stage and the succeeding compression stage;
• an upstream side temperature sensor arranged on the suction flow path between a connection portion with the first spillback flow path and the first compression stage;
• and
• a controller configured to control each of the first spillback valve and the adjuster, wherein
• each of the first compression stage and the succeeding compression stage includes:
• a cylinder unit;
• a piston;
• a piston rod connecting the piston to the crank mechanism;
• and
• rod packing that seals between the piston rod and the cylinder unit,
• the first compression stage is of an air cooling type and an oil free type,
• at least a part of the succeeding compression stage includes a leak gas discharge unit configured to return leak gas from the rod packing to the suction flow path, the controller is capable of executing:
• a first control of referring to suction temperature acquired by the upstream side temperature sensor to control the first spillback valve so that the suction temperature falls within a predetermined temperature range;
• and
• a second control of controlling the adjusting means so that a processing amount of the succeeding compression stage is adjusted according to a change amount of pressure in the intermediate flow path caused by the first control, and
• the predetermined temperature range is set to a range higher than a reference temperature based on liquefaction temperature of air and less than 0° C.