Bioconversion to address environmental impacts of grape winery waste by conversion to value added products
Görgens, J F
Stellenbosch University. Department of Process Engineering
Du Toit, W J
Haigh, K M
Key to Winetech’s “Greening the Industry” initiative is a common methodology to assess implementation of new and alternative technologies. This project developed such a methodology, through rigorous simulation of winery processes, to reduce the environmental impacts and production costs.
A process simulation of white wine production at a large winery was generated using Aspen Plus® based on published data and augmented with winery data. From there potential technologies for the valorisation of waste were identified and integrated into the initial winery simulation to generate a series of scenarios. An AspenPlus® simulation of a white wine winery was generated which reasonably represented the process. However the predicted wine volume of 528 litre per ton of grapes (alcohol was 13.4% ABV) was lower than reported by industry. The predicted lees mass was approximately double what was expected, indicating discrepancies between reported winery outputs and basic mass flow theory.
Three technologies and five scenarios were investigated and it was found that flour making had the best economic potential with an Internal Rate of Return (IRR) of 42%. However the environmental performance was also the worst of the investigated scenarios with an increased water requirement of 4 600 litres and increased carbon emissions of 31 ton/year.
While the process simulation requires further work there was sufficient variation in the results of the investigated scenarios to demonstrate that this methodology does have potential. The investigated methodology has a lot of potential to assess and compare a series of bioconversion technologies. Industry support is required to get a better understanding of the winemaking process from a mass and energy balance perspective and thus improve the initial simulation.