Pretoria-based specialised engineering solutions company Rand Technical Services (RTS) and its Norwegian principal Hystorsys are in the final stages of the development of its nonreciprocating and low-maintenance compressors, which are suited to the mining and industrial context, reports RTS chairperson Ian Fraser.

“It is difficult to design a compressor that has minimal mechanical parts, yet measures up to international operating standards, but this was achieved through a lengthy research and development programme by the two companies,” he adds.

Senior Hystorsys executives visited South Africa last month to discuss marketing and product distribution strategies, which RTS believes will elicit significant interest from local manufacturing industries.

Fraser reports that the key features of the gas compression technology are that there are few mechanical parts involved in the compression process and that large volumes of gas may be stored in a small space.

Using waste heat, the compressor is operated at almost no energy cost. As a result, the metal hydride compressors developed should have a low maintenance level and, hence, also low maintenance costs.

“Solid matter consists mostly of space. Metal Hydride technology exploits this by making the subatomic spaces available for storage of gas components.

“A special group of metals can absorb and release hydrogen and together the hydrogen and the metal form so-called metal hydrides,” Fraser explains.

The hydrogen is chemically bound to the metal at an atomic level and is, therefore, in the gas phase and is no longer volatile.

The metal hydride alloys are then processed into a fine powder and stored in a pressure vessel.

By means of a defined thermal management process, a metal hydride compressor compresses hydrogen in a safe and energy-efficient manner – absorbing hydrogen at low pressure and releasing it at high pressure.

“Pressures up to 800 bar are feasible with this technology,” notes Fraser.

He adds that Hystorsys realised that if it heated the hydrogen in a phased manner, it would result in a continuous flow of compressed hydrogen. “So one has a hydrogen compressor with no moving parts.”

The only replaceable parts on the compressor are the solenoid valves.

“These compressors experience little wear and tear because of the lack of moving parts, which means that there is minimal maintenance, lower operational costs and less downtime.

“This is significant for the industry because it means that we may move towards a future where there is no longer a need for reciprocating compressors,” highlights Fraser.

Another key feature of the compressor is the range of industries it can be used in. It can be used in any hydrogen-dependent application, such as the hydrogen energy industry, which is in the process of being developed through the conversion of cars and other vehicles to hydrogen fuel.

Fraser points out that, at present, two of the largest industries that will potentially benefit from the technology are the power generation and the metal production industries.

“The power generation industry uses hydrogen to provide a low resistance atmosphere in large generators. South Africa is also a key supplier of steel locally and internationally, and the use of gas compression technology in the steel annealing process means that manufacturers are able to achieve an increased efficiency and reduced cost,” he concludes.