High Pressure Generation Unit (HPGU) Includes the Gas Storage and Processing Units and Leak Test Module (LTM)
High Pressure Gas Generation, Storage and Recovery System
The high pressure gas generation unit (HPGU) includes the gas storage and gas processing components, housed in two separate ISO certified purpose-built fully containerised solutions for easy transport and onsite installation.
The gas storage container houses all of the gas storage volumes for both filling the high pressure vessels (HPVs) along with the recovering the forming gas.
The gas storage is split into three separate areas within the gas storage container. These are the low pressure recovery volume unit, intermediate gas storage unit, two gas recovery storage units and lastly the high pressure storage unit.
This container also houses the fueling panel which directs high pressure gas from the HPGU over to the Leak Test Module (LTM). A recovery panel directs flow through to the low pressure gas recovery volume from all of the defuel panels and the low priority gas recovery bank.
High Pressure Gas Processing Unit
The process container contains the pressure generation equipment and components required for pressurising the forming gas for testing hydrogen pressure vessels.
The main elements are the gas compressors and gas boosters along with all the pipework, valves and ancillaries around generating pressure in the system.
The main control panel for the high pressure gas unit (HPGU) system is located within the process container and has a direct feed to the main SCADA panel which is located next to the two leak test module (LTM) loading zones.
The control panel is fed by four other remote I/O panels, one in the storage container and one for each remote defuel station. There’s also a link between both chillers and the main SCADA panel.
There are two chillers that accompany the HPGU, the primary duty chiller and the ultra-low chiller, which are situated outside of the storage and process containers.
The primary chiller cools the forming gas before, during and after each stage of gas compression by the gas booster and gas compressors. The chiller feeds a manifold within the container which in turn distributes the coolant out to the various heat exchangers within the container.
The ultra-low chiller feeds a heat exchanger integrated with the fueling panel located inside the storage container, cooling the gas down prior to fueling the hydrogen pressure vessels.
Leak Test Modules
The leak test module (LTM) is part of the overall high pressure generation unit (HPGU) system that tests the leak tightness of high pressure vessels (HPV).
High pressure vessels are firstly loaded onto a gas test fixture (GTF), then onto the conveyor system by automated guided vehicles, to the loading bay where the pressure vessels QR codes and GTF RFID codes are automatically scanned for tracking. The GTF is lifted and conveyed into the vacuum test chamber. Once securely positioned inside the chamber the GTF is automatically coupled and connected.
Each gas test fixture holds 4 high pressure vessels for leak testing. When the HPVs are in position, the programme first pulls a vacuum within the chamber checking for a gross leak by charging the product with a set amount of test gas. Once the gross leak check is complete the hydrogen tank is fuelled with forming gas before being held at pressure to undergo the pre-determined leak test.
Once complete the HPVs are defueled in stages, partly within the chamber but mostly occurring at one of two external defuel stations. Once the HPV reaches a set pressure within the chamber, the charge line is vented before decoupling the GTF. Locking pins are then actuated to release the GTF and the conveyors move the GTF to an external defuel station. Once defueled, the conveyors move the GTF back to the loading zones to be removed from the leak test module (LTM).
A leak test is also included as part of the test, injecting a known amount of tracer gas into the vacuum test chamber whilst no hydrogen pressure vessel is present. This test ensures the mass spectrometer is working as intended and calibrated to the correct range, using low pressure gas.