Speaker
Description
In 2019, Linde received the order to deliver a large 4.5K helium refrigeration system for the Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt, Germany. The particle accelerator for heavy ions (SIS100), a fragment separator (Super-FRS) and several experiments are operated using superconducting magnets, all cooled with helium supplied from one central cryoplant.
Due to the different requirements of the individual systems, a wide range of cryogenic loads are covered by the cryoplant. While operating in a steady state, the main cold box delivers up to 14kW at 4.5K and 49kW at 50 to 80K.
The Super-FRS has a large cold mass of ~1500t. Cool-down and warm-up are rare and time-consuming procedures. Therefore, a separate unit with indirect LN2 cooling is provided. Advantageously, the compressor of this cool-down and warm-up unit can be used as a redundant compressor for those of the main cold box. It may replace the function of one of the two HP or two LP compressors.
The combination of floating high and medium pressure with a process integrated 20,000L LHe dewar enables rapid adaption to load change. Using a floating pressure cycle, high efficiency is maintained even at low turn-down operations; as low as only 20% of the design load.
The paper covers the process design and the control strategies for load adaption.
