Bulk cryogenic liquid pressurized dispensing system and method

A system for dispensing a cryogenic liquid comprising:

• a. a bulk tank defining an interior that is adapted to contain a supply of the cryogenic liquid, said bulk tank having a pressure building;
• outlet in a bottom portion of the interior and a dispensing outlet in the bottom portion of the interior that is separate from the pressure building outlet;
• b. a pressure builder having an inlet configured to receive cryogenic liquid from the pressure building outlet of the bulk tank and an outlet in communication with a top portion of the interior of the bulk tank;
• c. a liquid dispensing line configured to receive cryogenic liquid from the dispensing outlet of the bulk tank;
• d. a storage pressure sensor configured to detect a pressure of a supply of cryogenic liquid contained within a bottom portion of the interior of the bulk tank;
• e. a saturation pressure sensor configured to determine a temperature or a saturation pressure in the bottom portion of the interior of the bulk tank;
• f. a pressure building valve in circuit between the bottom portion of the interior of the bulk tank and the inlet of the pressure builder;
• g. a vent valve in communication with the top portion of the interior of the bulk tank;
• and
• h. a controller in communication with the storage pressure sensor, the saturation pressure sensor, the pressure builder valve and the vent valve, said controller programmed to:
• i) determine a bottom pressure using data from the storage pressure sensor,
• ii) determine a saturation pressure of the cryogenic liquid,
• iii) compare the bottom pressure with the saturation pressure, and
• iv) open and close the pressure builder valve and the vent valve during dispensing of cryogenic liquid through the liquid dispensing line based on data from the storage pressure and saturation pressure sensors, including compensating for a loss in a liquid head pressure due to a decreasing liquid level of a supply of the cryogenic liquid in the bulk tank during dispensing of the cryogenic liquid through the liquid dispensing line, by raising a pressure set point to turn on the pressure building valve so that cryogenic liquid flowing through the dispensing line is maintained at a generally constant pressure based on the saturation pressure.