Ethanol from Industrial Waste Gas
Turning waste into energy
Swayana (Pty) Ltd is a green chemicals and biofuels company based in South Africa. The company was established in 2016 and their flagship project is the production of industrial-grade ethanol from the furnace off-gas from the Samancor Middelburg Ferrochrome (MFC) smelter. They are able to achieve industrial-grade ethanol by using a microbial fermentation process developed by the American firm LanzaTech.
Zutari was appointed to complete the bankable feasibility study (BFS) for a process that uses genetically engineered microbes to convert furnace off-gas to export quality ethanol for use as a fuel additive. The plant comprises medium-voltage (MV) loads, including a bioreactor, compressors, distillation plant, cooling water system, and other low-voltage (LV) loads.
The MV process loads are rated at 6.6 kV, with pumps ranging up to 800 kW and a total load of 1 MVA. The 6.6 kV substation included 2 x 16 MVA 22/6.6 kV transformers and 44 x 6.6 kV panels.
An approximate 15% capital expenditure (CAPEX) and operational expenditure (OPEX) estimate has been provided to the client to get the project to financial close. This included a logistic study, equipment selection tradeoff studies, and biomass byproduct studies.
Zutari was also responsible for the mechanical, civil, structural, and electrical engineering, as well as the control and instrumentation (C&I) for the project. The design team also did the mechanical assessment of fabrication and the installation of the bioreactors; developed a 3D model; conducted geotechnical investigations; and developed a capital and operational cost estimate. The team also conducted trade-off studies between various technical options for individual packages; optimised the distillation and dehydration package, and further developed and designed the subsequent engineering packages to a BFS level.
Zutari was appointed to complete the bankable feasibility study (BFS) for a process that uses genetically engineered microbes to convert furnace off-gas to export quality ethanol for use as a fuel additive.
Despite the tight deadlines and other tough project constraints, everyone pulled together and supported each other. Converting exhaust gas from a smelter into industrial-grade ethanol through a biological process was innovative.
The team faced multiple challenges that are typical during a multidisciplinary project, such as collaborating between different Zutari offices (Cape Town, Tshwane and Johannesburg) and ensuring that everybody interpreted the client’s requirements in the same way. A change in mechanical equipment affects the electrical engineering designs, which in turn affects the civil and structural engineering designs. To overcome this challenge, strong oversight, close collaboration between team members, and the latest digital software were used.
“Despite the tight deadlines and other tough project constraints, everyone pulled together and supported each other. Converting exhaust gas from a smelter into industrial-grade ethanol through a biological process was innovative. This has only been performed a handful of times in the world and this is a first for Africa,” says Simon Fairhurst, Zutari Technical Director.
*The Aurecon Africa business has been officially renamed Zutari as at 21 July 2020. Zutari acquired Aurecon Middle East on 20 November 2020.
