As the world searches for less polluting sources of energy, a number of companies have built pilot plants to determine how best to manage the manufacturing processes for these new materials. The challenge for Leigh Creek Energy Limited was to design, build and commission a pilot plant to transform coal from its solid state into a gaseous form and monitor the technical and environmental performance of the process.
The in-situ gasification process (ISG) produces methane, hydrogen and other valuable components. The synthetic gas (syngas) can be used to produce electricity directly or further refined into a variety of products including synthetic methane and ammonia.
The ISG demonstration project was built to inform the design for a potential commercial facility. It involved the construction of an above-ground plant and a below-ground single ISG gasifier chamber. The pilot plant was built north of Adelaide, South Australia, in the Leigh Creek Coalfield. The site was selected as the result of a screening process using criteria that covered environmental, technical and commercial aspects to ensure it would be safe and minimize any environmental impact.
The pilot project operated 24/7 and has resulted in the successful production of syngas—with a peak flow rate of 7.5mmcf/day. “The success of this trial has effectively unlocked a large energy resource of huge value and captured key data that validates the fact that this proven ISG technology can be successful in a commercial application,” explained Phil Staveley, managing director of Leigh Creek Energy.
The ISG process is a chemical conversion from solid coal to gas. For the reactions to commence, air is introduced through the inlet well and an initiation device is used to create very high temperatures. As the temperature and oxygen concentration reach optimum levels, a series of reactions convert the solid fuel into syngas, which is then extracted through the outlet well.
The area in the coal seam where the gasification takes place is referred to as the gasifier chamber and the reactions that form syngas typically occur at temperatures of between 900?C and 1200?C. Given the process, safety and environmental considerations for the plant, the choice of control and automation system requirements was of paramount importance.
ATSys, a Rockwell Automation Recognized System Integrator, was commissioned to develop the control system for the plant. “We selected Rockwell Automation hardware and software for this project because it has been proven to be reliable and we could be confident that the technology would be fit for purpose for this project,” said Andre Tassone, managing director, ATSys.
The Leigh Creek Energy facility incorporates a number of Rockwell Automation products, including the PlantPAx distributed control system, Integrated Architecture with CompactLogix controllers and PowerFlex drives, and dashboard analysis using FactoryTalk View, VantagePoint and Historian software suite.
