Enhancing Energy Efficiency in a Jojoba Oil Biorefinery: A Case Study in Performance Optimisation

• An integrated and systematic methodology is proposed for analysing and optimising biorefinery systems. • The energy performance of a jojoba oil biorefinery is substantially improved. • High energy efficiency is achieved with minimal additional capital expenditure. • Energy integration is identified as a key driver for sustainable biorefinery operation. • Hot utility requirements are eliminated through effective energy integration. The biorefinery concept, which focuses on converting waste feedstocks into value-added chemicals and biofuels, plays a vital role in the transition to sustainable industrial systems. A critical determinant of the economic viability of such processes is their energy efficiency. This study presents a systematic and hierarchical methodology for the performance analysis and energy-driven optimisation of biorefinery designs. The proposed approach integrates advanced energy integration techniques to enhance process-wide energy utilisation. These techniques combine Pinch Analysis principles, rigorous process simulation using Aspen® packages, steam generation, and carbon credits consideration. A novel Jojoba oil biorefinery is employed as a case study, targeting the production of high-value Jojobyl alcohols (JAs) and fatty acid methyl esters (FAME) as a co-product. Initial utility demands were calculated as 9794.3 kW (cold) and 1978.0 kW (hot) for an annual output of 2[300 metric tons of JAs. Pinch Analysis revealed the process as a threshold problem, requiring only cold utility. The process exhibits a surplus of heat content in the process hot streams capable of satisfying the heat requirement of the cold streams. Therefore, no hot utility is further necessary. Two energy-saving scenarios were developed to optimise the heat exchanger network (HEN): one minimising energy consumption (Design 1) and another incorporating steam generation (Design 2). Exchangers in the network are of the shell-and-tube type. Aspen Energy |Analyzer® (v12) has been used for the simulation of the heat exchanger networks. Aspen HYSYS® (v12) was used to rigorously simulate the properties of process stream components. Results achieved a 20.2% reduction in cooling utility demand for Design 1, while Design 2 achieved 39.6% reduction, with both designs eliminating the hot utility requirements. The steam generation-based solution delivered an estimated annual profit increase of $519898.1 and an overall CO 2 emissions cut of 10326.5 t/y. Carbon credits of $774487.5 every year were gained as an extra revenue when participating in the EU Emission Trading System. These results demonstrate that strategic energy integration significantly enhances both the economic and environmental performance of biorefineries. The study directly contributes to the advancement of a sustainable bioeconomy and supports the objectives of UN Sustainable Development Goal 7: Affordable and Clean Energy.