Waste apple pomace conversion to acrylic acid: Economic and environmental assessment

Abstract

The global demand for acrylic acid (AA) is increasing due to its wide range of applications. Due to this growing demand, alternative AA production strategies must be explored to avoid the exacerbation of prevailing climate and global warming issues since current AA production strategies involve AA production using fossil resources. Investigations on alternative strategies for AA production therefore constitute an important research interest. The present study therefore assesses waste apple pomace (WAP) as a feedstock for the sustainable AA produc-tion. To undertake this assessment, process models, based on two production pathways were designed, modelled and simulated in ASPEN plus® software. The two competing production pathways investigated include a process incorporating WAP conversion to lactic acid (LA), prior to LA dehydration to generate AA (denoted as the FD pathway) and another process involving WAP conversion to propylene, prior to propylene oxidation to generate AA (denoted as the TFO pathway). Economic and environmental performances of the FD and TFO pathways were assessed via the minimum selling price (MSP) and potential environmental impacts per h (PEI/h) metrics. The study was able to show that the FD pathway presented an improved economic performance (MSP of AA: US $1.17 per kg) performance compared to the economic performance (MSP of AA: US $1.56 per kg) of the TFO pathway. Crucially, the TFO process was shown to present an improved environmental performance (2.07 kPEI/h) compared to the environmental performance of the FD process (8.72 kPEI/h). These observations sug-gests that the selection of the preferred AA production will require a trade-off between the performance measures, and the integration of a multi-criteria decision assessment in future work.