AES gets rubber manufacturers on the path to sustainable energy optimisation.

Jordan Smith, Gauteng Regional Manager at AES.

Jordan Smith, Gauteng Regional Manager at AES. Supplied by AES

For decades, South Africa’s rubber has been a major material used in the HVAC manufacturing sector among others. Now, with increasing pressure to address energy usage and optimisation, the intervention of Associated Energy Services (AES), a leading operations and maintenance service provider to the steam and boiler sector, could be a game changer. 

AES Gauteng regional manager Jordan Smith, and associate director operations Ray Lund – who work closely with rubber belting and tyre manufacturers in Gauteng and the Eastern Cape respectively – note that there is a strong drive in and among rubber companies to exchange fossil fuels for renewable energy sources.

Steam plays an essential role in vulcanisation, an integral process at the heart of manufacturing of all rubber products: from tyres and conveyor belts carrying raw materials in industry, to sealing components such as gaskets or protective wear such as wetsuits or gum boots. 

With the application of steam, raw natural and synthetic rubber (which has the consistency of soft bubble gum) is transformed into its final durable – yet also elastic – form.

During tyre manufacture, the green tyre is placed in a mould, into which highly pressurised steam is fed. This vulcanises the tyre in the curing machine, where its parts are compressed together, giving the tyre its final shape and durable qualities.

Lund notes that tyre manufacturing comes with stringent quality and safety requirements: “This means that good control of the steam and heat energy is required when a tyre is being cured.” 

A press system is used to manufacture rubber belts through the process of steam heating, which provides the pressure and temperature necessary to bond and cure the components.

Smith points out that steam provides a consistent source of heat: “If the steam temperature drops and does not heat all sections of the plates equally, that results in a poorly-bonded product which will not deliver the required strength and durability. When there is excess temperature and pressure, the belt produced is too brittle,” he explains.

Steaming towards the future

Although rubber production has changed very little over the years, the sector is now facing many challenges. Ever-increasing cost pressures coupled with an industry move to greener suppliers has driven the need for innovation.

“Recently, clients have started moving from cyclically heated presses to continued heated presses where plates are not cooled and reheated between batches,” Smith explains.

The condensate generated in the manufacturing process can also be recycled, delivering water and sensible heat back to the boiler house for re-use. 

The greatest change – and challenge – remains the replacement of carbon-intensive fossil fuels. 

“With several clients across a range of industries already using biomass, we are in strategic discussions with rubber companies, which are considering a move to various forms of renewable energy. This cannot be avoided and entails a significant technological shift,” advises Lund.

Rubber manufacturers with global parent companies are at the forefront of this transformation, which entails striking a balance between the social governance commitments of a multinational and South Africa’s often harsh economic challenges. Change must be carefully managed to ensure long-term sustainability and not put businesses at risk.

Lund elaborates: “A fuel switch does, inevitably, necessitate substantial capital investment if clients want to run their plants effectively, efficiently and competitively. A large amount of capex is needed to realise those gains.”

He points out that generally, the technology required to burn biomass efficiently can be more expensive, adding that as more companies convert to biomass and demand grows, so too may the cost thereof.

“Unfortunately, there is a view that, because biomass is waste, it should be inexpensive. Typically, however, we find that locally-owned rubber sector companies are very challenged by the capital investment required and the costs entailed. Due to their global ESG (economic social and governance) commitments, their international counterparts are more inclined to consider workable solutions,” Smith observes.

Source: AES