The best growth scenario for the local sugar industry is to diversify its products to create multiple revenue streams, says research organisation the Sugar Milling Research Institute NPC (SMRI) strategic research group leader Dr Kitty Foxon.

Biochemicals and bio-materials from sugar cane-derived feedstocks, such as sucrose and fibre, would likely attract the best value from each stick of sugar cane. While blending bioethanol with transport fuels would provide important health benefits associated with reduced particulate emissions to South Africans.

Using existing sugar cane processing infrastructure to generate value from additional crops could also allow for more efficient use of agricultural land, as well as existing logistics and agro-processing infrastructure.

“We are embarking on a study in collaboration with researchers from Stellenbosch University, funded by the Department of Science and Innovation (DSI), to identify which of these diversified products show potential to improve the sustainability of the sugar cane value chain. This project will inform policy support options and is being done in conjunction with the South African Sugarcane Value Chain Master Plan processes.”

Foxon notes that this study involves the screening of diversification candidates that have shown potential as financially viable products from previous studies, and subjecting the top two candidates to detailed market studies and technoeconomic analysis.

The detailed analysis of individual product and technology options will demonstrate whether projects based on these options, which qualify for environmental, social and governance investment, can be designed.

Specialists in marketing, financial modelling, policy development and investment strategies will partner with the SMRI and Stellenbosch researchers to complement the project teams’ skills in technical, technoeconomic and environmental modelling.

“As additional funding becomes available, we hope to repeat the methodology for more diversified product candidates. The results will be made available to sugar cane growers and millers, who can then choose to develop the concepts into real projects.”

Foxon stresses that opportunities for diversification which do not require significant external investment and policy support are likely to be small in scale.

Product and technology combinations that can yield benefits for a broad range of stakeholders across the value chain are also likely to be used for high-volume, relatively low-value commodities, such as single-use compostable bio-plastics made from sugar, she argues.

“These will require an enabling policy environment to be financially viable. Similarly, incentives, import protection and investment in associated services for any other high-volume product would likely be necessary to provide long-term market stability”.

SMRI research and development manager Steve Davis points out that local millers have historically invested in diversified production that includes the cogeneration of electricity, animal feed, alcohol and furfural.

“The industry currently employs about 65 000 people directly, and through upstream and downstream multipliers, it supports a further 270 000 indirect jobs. Therefore, the sugar industry sustains about a million livelihoods, mostly in deep rural areas, where income from industry is often the only available income other than social grants.”

4IR

“While not yet established in local mills, the local sugar cane processing industry is looking towards Fourth Industrial Revolution (4IR) techniques, instruments and software to better monitor and control processes to improve efficiencies, recoveries and reduce costs,” says Davis.

The DSI, through its Sector Innovation Fund programme, and stakeholders in the sugar industry, are co-funding the Sugar Factory 4.0 project run by the SMRI.

The R20-million programme focuses on developing 4IR principles in the local sugar industry. The project was initiated in 2019 and will be completed later this year.

Foxon highlights four subprojects that have been developed to pilot stage for Sugar Factory 4.0.

The first includes an energy-monitoring dashboard that has been installed at local manufacturer Gledhow Sugar Company’s factory, in KwaZulu-Natal, to provide real-time information on energy consumption of different categories of energy use in the factory.

A target-setting algorithm will also be set up at Gledhow this year, which will enable factory staff to track energy use performance against targets on a daily basis.

For the second project, a data-driven model, used at RCL Foods Limited’s Komati sugar mill, provides a setpoint for the cane crushing rate to alleviate a bottleneck occurring later in the factory. This has been run in open loop since last year and, after refinements, will be tested in closed loop later this year.

The two other subprojects are examining improved sucrose recovery efficiency at producer Illovo Sugar Africa’s Noodsberg sugar mill, in KwaZulu-Natal, and improved sugar extraction efficiency at Komati sugar mill. Model building and testing will also take place this year.

Foxon emphasises that the SMRI is also developing three sensing systems for cane preparation, diffuser liquid holdup and centrifuge operation using machine learning and deep learning principles.

“If successful, these can be implemented into automated control systems, all of which will target increased sugar recovery at relatively low investment cost,” elaborates Foxon.

Davis reiterates that the extra analytical data that can be rapidly gained from the SMRI near infrared spectroscopy chemical analysis technology, which has been implemented at all local sugar mills since 2019, can also lead to a “better understanding of deviations from ideal conditions in the process”.

He concludes that, “should feasible product diversification options be implemented, it will be essential to maximise efficiency and productivity of the entire sugar cane biorefinery, for which process optimisation tools will be required”.