University of KwaZulu-Natal economics Masters student Warwick Thomson put the case for the potential of diverting biomass from South Africa’s sugarcane crop for the manufacture of selected bio-based polymers or plastics, during a short, non-refereed paper he presented at the recent South African Sugar Technologists’ Association Congress in Durban. Thomson is a member of the SMRI Sugarcane Biorefinery Research Chair and currently funded by the Department of Science and Technology. His presentation was based on research he conducted in the third quarter of 2016. Thomson directly engaged with 17 representatives including industry directors, sustainability managers, researchers and those in positions well versed on the subject. The questionnaire was based on 13 closed and 18 open-ended questions resulting in both qualitative and quantitative findings.
DESPITE massive hurdles facing the establishment of a viable product-diverse bio- economy based on sugarcane in South Africa, the sector is optimistic that opportunities exist to produce “green” plastics or polymers from sugarcane, according to Thomson’s study.
The purpose of the research, Thomson said, was to identify the viability of bio-based polymer production in South Africa.
“If South Africa could produce these bio-based polymers, we would move closer towards a bio- economy, being less dependent on fossil resources. Greenhouse emissions would be reduced and further opportunities for employment in the green economy would become available,” he said.
STRUCTURAL WEAKNESSES SHOULD BE ADDRESSED FIRST
However, according to the study, structural weaknesses in the current industry should be addressed before any conversion investment for production is considered.
Areas of concern included a constant, season-independent supply of sugarcane-based raw materials to ensure a cost effective and sustained supply of products to markets and assuring the cost containment of the bio-plastics manufacture against those produced by the country’s petro-chemical industry.
Further hurdles the study identified included the high cost of factory conversion and whether or not South African consumers would choose locally produced bio-ethical plastic products – which would, at least initially, cost more than those produced by the petro-chemical industry.
INTERNATIONAL PRODUCTION OF GREEN PLASTICS ON THE RISE
Thomson said the manufacture of partially bio-based polyethylene terephthalate (PET) was expected to increase considerably over the next few years in countries such as India, Brazil and China, where both the manufacturing and sugar industries are heavily subsidised by their respective governments. This, he said, added to the concern about whether or not South Africa could compete on price.
Currently the South African retailer, Woolworths and soft drink giant, The Coca-Cola Company, are offering South African consumers a bio-based polymer packaging produced from Brazilian sugarcane.
Also, Coca Cola International claims to be absorbing the higher costs for their 30% bio-based polyethylene terephthalate (PET) bottle (Coca-Cola Company 2012) rather than passing them on to the consumer.
ETHYLENE IS UNDER SUPPLIED IN SOUTH AFRICA
South Africa is primarily an importer of polymers and monomers which could be potentially produced from sugarcane. For example, ethylene is a monomer for many types of polymers and is currently severely undersupplied in South Africa, the report said.
“The first two polymers I focused on in my study were polyethylene which is the world’s most popular polymer in terms of its production. The polymer is produced in many countries including South Africa but it is under supplied. As a result, we have to rely on the global market, which was estimated at $134 billion in 2014,” Thomson said.
The petro-chemical giants Sasol and Safripol produce polyethylene domestically.
However, polyethylene can be produced from sugarcane converted into ethanol and then ethylene. The resulting products are identical to fossil-based polyethylene in terms of structure and properties. This should facilitate market uptake. On the other hand, polyethylene in general is not biodegradable, so there is no added benefit when it comes to recycling and disposal” Thomson said.
“The second bio-based polymer considered in my study is polylactic acid (PLA) which is produced from lactic acid obtained through fermentation of carbohydrates such as sucrose. Globally, it is now one of the most popular materials to produce bio-plastics and one of the few that is biodegradable under certain conditions,” he said.
However, he added that polymer was not commercially produced in Africa as yet and there were just a few plants in the rest of the world.
“It is for this reason that it still has a relatively small market share compared with polyethylene. However, demand is expected to grow quite significantly over the next few years. And it is here that there is an opportunity for South Africa’s sugar industry,” Thomson said.
INFRASTRUCTURE INVESTMENT KEY FOR SUCCESS
Investment and development in infrastructure that relate to cost reduction and improved production efficiencies are critical for success. “Handling the foreign competition is going to be really important. Also we would have to rely on sugarcane growers to supply sugarcane in the required quantities. At the moment the local sugar industry only produces sucrose and a limited number of other products. In Brazil, for example, the government is subsidizing the industry which not only allows them to produce sugar at a price we can’t always compete against, but also the Brazilian industry has been able to expand their product portfolio to include ethanol for the fuel and bio-based plastics markets. The industry is very flexible and able to adapt to the demands of the market. If the oil price is high, the sugar mills produce ethanol, if the sugar price is high they switch to sugar production,” he said.
Thomson said further work to be done in his research related to a cost benefit analysis, the cost effectiveness of the production of bio-based polymers and what government support could be made available to support the conversion to a more bio-based economy.
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