Nitrogen pumping unit is a highly sophisticated device which performs several simultaneous functions in order to convert nitrogen from liquid to a gaseous phase.
Firstly the nitrogen unit is fed with liquid nitrogen at a temperature of –196 C. It then pumps the liquid nitrogen to high pressure before it supplies heat to transform the liquid nitrogen into a gaseous phase.
All the necessary power to perform the above operation is supplied by a diesel engine, while a sophisticated heat recovery system supplies the required thermal power.
How It Works
Hydraulic pump power and liquid nitrogen heat are supplied via the diesel engine power pack.
The system converts heat energy into the engine coolant system to obtain heat for the liquid nitrogen vaporisation process.
The liquid nitrogen is pressurised by the reciprocating pistons of the triplex pump to the required downstream pressure, the high pressure liquid nitrogen then flows through the nitrogen vaporiser and is vaporised to gaseous nitrogen.
The vaporiser coolant system and discharge temperature should be maintained by the pump operator at typical levels of 60 C and 20 C.
The heat balance between the hydraulically loaded engine and the nitrogen vaporisation circuit is obtained by heat transfer through a plate heat exchanger.
The engine coolant is maintained in all conditions by thermostatic control of the coolant flow to either the engine coolant pump or to an air blast radiator.
Increased engine loading is achieved using a hydraulic vane pump (heat load), the load applied is operator controlled by activation of the sequence valve. This process is used during periods of high pump rates to ensure coolant water temperature is maintained for the nitrogen vaporisation process.
Closed loop hydraulic system: this system uses separate hydraulic pumps for the triplex pump drive and heat load, this system allows the heat load to be applied independently of the operation of the triplex pump.
Triplex pump drive is obtained using a variable flow high pressure piston hydraulic pump.
- Maximum working pressure: 15,000psi
- Working temperature range: -10 oC to 50 oC
- Maximum flow rate: 90,000scf/hr or 1,500scf/min
- Design maximum flow rate temperature:20oC
- Maximum simultaneous flow and pressure conditions: 1,500scf/min at 10,000psi or 1,000scf/min at 15,000psi
- Fuel Capacity: 225 litres/60 USG
- Design ambient temperature: -20 oC to 50 oC
- Design environment: Onshore/Offshore
- Hydrostatic Test Pressure: 22,500psi
- 2006/42/EC Machinery Directive
- 97/23/EC Pressure Equipment Directive (PED)
- 2009/105/EC Simple Pressure Vessels Directive
- 2004/108/EC Electromagnetic Compatibility Directive
- DNV SFC 2.7-1 Offshore Containers June 2013
- BS EN 12079-1:2006 Offshore containers and associated lifting sets
- BS EN 795:2012 Personal Fall Protection Equipment