Technical Aspects of Natural Gas Pyrolysis in Liquid Metal Bubble Column Reactors

The pyrolysis of low alkanes (in the following short “pyrolysis”) has already been investigated during the 1960s. However, none of the reactor systems used at the time are capable of continuous operation. Therefore, the Karlsruhe Institute of Technology has intensified the development of the promising liquid metal bubble column technology in recent years, which is capable of continuous operation. Various key aspects have been addressed, such as scale-up and the pyrolysis of high-caloric natural gas. Herein, further developments for a pilot scale system have been investigated, which concern increased throughput and long-term operation capabilities. Careful evaluation of the impact of according measures has been done, which shows that the achieved scale-up has only negligible effects on the pyrolysis outcome. The effects of the scale-up on residence times are negligible. The bubble formation behavior depends on the throughput and the characteristics of the orifice. Wall effects are marginal. Fundamental minimization of weeping could not be confirmed. Reactor pre-chambers in combination with tin collection chambers are recommended for further scale-up. An increase in the volume flow should be examined. In terms of long-term operation , head as well as feed pressure control is recommended.