The three-year operations and maintenance (O&M) agreement for petrochemicals giant Sasol New Energy’s (SNE’s) gas engine power plant project in Sasolburg, which was signed in May this year, will open many doors for power plant solutions and services provider Wärtsilä, says Wärtsilä Solutions Support Services South Europe and Africa GM Aditya Pal Singh.SNE
was created by the Sasol group to leverage its key competitive advantage of developing and commercialising new technologies, as well as implementing and operating large-scale facilities based on these technologies.
Sasol is exploring renewable and lower carbon energy resources, as well as carbon capture and storage solutions.
The 180 MW SNE plant is expected to start producing electricity towards the end of this year, Sasol reports. It will be the largest gas-fuelled power plant on the African continent.
Owing to the plant’s low emissions, it will also be a major advance in the development of Sasol’s electricity business, says SNE low carbon electricity GM Kribs Govender.
The plant will provide the energy needed to power the group’s major new production facilities, including the Sasol Wax Expansion and Ethylene Purification Unit 5 projects currently under construction in Sasolburg. “The gas engine power plant employs a cleaner fossil fuel-based technology than traditional coal-based technology and will reduce the group’s carbon dioxide (CO2) emissions by about one-million tons a year,” Sasol states.
The main products of the combustion of natural gas are CO2 and water vapour – the same compounds we exhale when we breathe, Singh explains.
Coal, however, is composed of more complex molecules with a higher carbon ratio and higher nitrogen and sulphur content. When combusted, coal releases higher levels of harmful emissions, including CO2, nitrogen oxide (NOx) and sulphur dioxide (SO2) into the atmosphere, he says.
Coal also releases ash particles – substances that do not burn but are instead carried into the atmosphere and contribute to pollution – into the environment.
Contrastingly, the combustion of natural gas releases small amounts of SO2 and NOx, virtually no ash or particulate matter and lower levels of CO2, carbon monoxide and other reactive hydrocarbons, Singh stresses.
“To generate four units of electricity from coal-based power plants, one has to gear up for the tedious job of handling 1 kg of environmentally hazardous ash.”
With gas-based technology, there are hardly any residual by-products requiring special care. This has a direct impact on the degree of maintenance and operation of the plant.
In addition, the various byproducts produced in the gas combustion process do not make maintenance challenging.
Compared with ossified coal, gas is easier to excavate, transport, transmit and handle, making the operation of a gas-based plant much simpler and cleaner, Singh states.
Wärtsilä’s operation and maintenance modules feature several best-practice solutions that will be implemented during the Sasol O&M operation for life-cycle efficiency, leading to improved performance, increased environmental efficiency and the prevention of the unexpected.