Liquid Hydrogen fuel storage
The liquid hydrogen depot is supervised and monitored from a control building nearby comprising the following units:
- a vacuum-isolated main storage tank with a usable inner volume of 270 m³ and a storage temperature of 20 K (-253,15 °C)
- a vacuum-isolated pilot tank with a usable inner volume of 55 m³
- two connection options to discharge from tank trucks
- a pressurising system
- a transfer pipe to test facility P5
- a transfer pipe to test facility P4.1
- security equipment.
Liquid Oxygen fuel storage
The liquid oxygen depot is similarly structured to the liquid hydrogen depot. It comprises:
- a vacuum-isolated storage tank with 210 m³ volume (90 K storage temperature)
- two connections for tank trucks and pressurising system
- a transfer pipe to test facility P5
- safety facilities.
Oxygen is supplied in appropriate fuel tank trailers of 15 cubic meters volume each. The stored oxygen is conveyed into the run tank via a 250 m long transfer pipe to test facility P5. The transfer pipe is technically identical to the hydrogen pipe. The conveyed quantity amounts up to 40 m³/h. Controlled evaporation of liquid oxygen in a connected heat exchanger is applied to exert the necessary pressurising needed for transfer from the LOX tanks.
Production plant for GN2
The operation of the test facilities and their dedicated supply systems requires a sufficient supply with gaseous nitrogen in different pressure stages. To cover this need the test facilities are fed from the upper area of the test site where the compressor unit D22 GN2 is based; it is operated from control room G56.
Production plant for GHe
The operation of the test facilities and their dedicated supply systems requires a sufficient supply with gaseous helium in different pressure stages. To cover this need the test facilities are fed from the upper area of the test site where the compressor unit D57 GHe is based; it is operated from control room G56.
Cooling water supply
Test facilities P4 and P5 are supplied with coolant from the elevated tanks N33, N63 and N63a. Test facilities P4 and P5 were cooled from the high-level tanks N33 and N63 before P4.1 was rebuilt into an altitude test facility. During the reconstruction work another transfer pipe and the elevated tank N63a were added to the cooling water system. The water collected in the low-level gallery is re-cooled as needed in the test facilities, and for P4.1 it is doped with anticorrosive agents. High-level tank N33 and N63 have a maximum volume of 1,000 m³, N63a can absorb up to 4,000 m³ heat-exchange water. After test on P4.1, the cooling water comes with a calculated mixed temperature of approximately 65°C. The new re-cooling facility has a performance of 822 kW maximum and cools water in two stages down to 7 °C to then return it to the elevated tanks.
1st stage: two plate heat exchangers with dry cooler (from 65 °C to 30 °C)
2nd stage: two air-cooled refrigerating units (from 30 °C to 7 °C)
The re-cooling of 6,000 m³ water (from 65 °C to 7 °C) takes 82 to 138 hours depending on the outside temperature. The cooling water throughput during the test at P4.1 for the diffuser strand equals approximately 1,900 l/s, the cooling water pressure being increased to 14 bars with two pumps. The condenser strand has a throughput of around 3,600 l/s.
Waste water treatment
The DLR site at Lampoldshausen operates a large-scale water treatment plant. Contaminated sewage water coming in from test facilities is treated in this neutralisation plant and can subsequently be channelled out into the environment fulfilling the legally prescribed thresholds. This plant was extensively modernised in the past years. Water outflows are subject to continuous and strong authority controls. The last expansion incorporated systems applying the so-called catalytic wet hydrogen peroxide oxidation (H2O2) and ultraviolet light as well as the so-called ammonia stripping. The physical extraction by blowing down ammonium provides a balance between ammonium (NH4+) and ammonia (NH3). A balance shift in favour of the gaseous and water-soluble ammonia commences once the pH value of 9 is exceeded. When a pH value of 11.5 is achieved, the nitrogen has been transformed into ammonia at 100 %. The pH value is gradually set to 10 as caustic soda is added to ensure a rapid mass transfer. The ammonia is feed into a circulation system and then transferred to gas phase via a trickle tray tower for stripping. The stripped air, now charged with ammonia, is circulated by fans, injected into a sulphuric washer and cleaned. Ammonium sulphate remains as a by-product (NH4)2SO4.
The benefits of this application are:
- the highest possible waste water quality (considering the extremely varying organic sewage water agents)
- no sewage water salting
- low susceptibility to failure thanks to simple reactor technology
- low consumption of human and economic resources
- easy expandability