A liquefier device configured for use with an air separation plant producing oxygen and nitrogen gas comprising:
- an inlet piping system to the liquefier device,
- an insulated box having a low pressure nitrogen gas purge feed to keep the insulated box dry, the box housing a plurality of multi-pass counter current flow heat exchangers each having a warm side and a cold side, a high pressure nitrogen bath boiler, a plurality of turbine expanders connected in parallel, a turbine exhaust phase separator, an oxygen production flash pot, a nitrogen production flash pot, and a nitrogen pump flash pot,
- the inlet piping system connecting to a piping and valve system of the liquefier device and including a take or vent gas oxygen inlet line into the insulated box, a take or vent low pressure column gas nitrogen inlet line, and a take or vent high pressure column gas nitrogen inlet line,
- said oxygen production, nitrogen production, and nitrogen pump flash pots and boiler each having a tube bank side and a shell side, the tube banks in said flash pots and boiler being partly submerged by a liquid nitrogen bath held by the shell side, the flash pots each having a liquid height controllable by multiple automatic liquid level control valves, and the boiler having a variable speed pump that will replenish the liquid in the boiler shell side,
- a plurality of turbine boosters connected in series, each of said turbine boosters having an operably associated fan cooled turbine booster aftercooler and surge valve,
- said multi-pass counter current flow heat exchangers including an oxygen cooler for cooling a flow of oxygen gas from the take or vent gas oxygen inlet line, a preheater for heating a flow of vaporized nitrogen produced by the boiler prior to entering the turbine expanders, an added cooling heat exchanger, and a condenser,
- each of the turbine expanders and turbine boosters having an operably associated inlet flow meter, and each of the turbine expanders having variable guide vanes and operably connected to one of the turbine boosters,
- the take or vent gas oxygen inlet line connected to pass the flow of oxygen gas sequentially through the oxygen cooler, boiler, and condenser, into the tube side of the oxygen production flash pot, and exiting the oxygen production flash pot as a subcooled liquid oxygen ready for storage,
- the take or vent low pressure column gas nitrogen inlet line joining a low pressure nitrogen gas line downstream from an auto pressure control valve on the oxygen cooler warm side, supplying a joined low pressure flow to a first of the plurality of turbine boosters, the low pressure nitrogen gas line containing vaporized liquid nitrogen from the shell side of the pump flash pot, the shell side of the nitrogen production flash pot, the shell side of the oxygen production flash pot, and from an exit of an auto liquid level control valve in a line off of the turbine exhaust phase separator,
- the joined low pressure flow being compressed in the first turbine booster and reduced in temperature in the aftercooler associated with the first turbine booster, and then being further compressed and reduced in temperature in at least one additional turbine booster and associated aftercooler before joining a line containing a combined flow of nitrogen gas from the take or vent high pressure column gas nitrogen inlet line and a high pressure gas line after exiting the oxygen cooler warm side, supplying a major nitrogen gas flow to a last of said turbine boosters and associated aftercooler,
- the major nitrogen gas flow upon exiting the aftercooler associated with the last turbine booster in a major flow line holding a heat of compression, said major flow line branching into a branch line to the oxygen cooler warm side, a branch line to the preheater warm side, and a bypass line, the branch and bypass lines recombining into the major flow line downstream from the oxygen cooler and preheater and sequentially entering one of the tube banks in the boiler and then the condenser, the major nitrogen gas flow providing a warm flow to the boiler which boils the liquid nitrogen bath in the boiler, and undergoing a heat exchange in the condenser with a gas flow in the high pressure gas line from the turbine expander phase separator, transforming the major nitrogen gas flow to a two-phase liquid gas nitrogen stream which is passed into the added cooling heat exchanger warm side, and then into the nitrogen pump flash pot tube bank to produce a single phase liquid nitrogen stream,
- a plurality of branch lines off of the nitrogen pump flash pot tube bank in which the single phase liquid nitrogen stream is directed, including a branch line to a nitrogen pump system which brings the single phase liquid nitrogen stream up in pressure, and a first line exiting the nitrogen pump system feeding the increased pressure stream to the boiler shell side to boil the increased pressure stream to a vapor point, and
- a line containing the flow of vaporized nitrogen produced by the boiler sequentially feeding the preheater and the turbine expanders connected in parallel, an exhaust flow carried in an exhaust line connected to an exit of the turbine expanders to the turbine exhaust phase separator, a nitrogen gas flow exiting the turbine exhaust phase separator in a line connecting to the high pressure gas line before entering the condenser cold side, and a liquid nitrogen flow exiting the turbine exhaust phase separator in lines connecting to the flash pots and to the line connecting to the low pressure nitrogen gas line.