Robust solar-energy system design and optimisation for reactive distillation column in methyl acetate hydrolysis process

Abstract

There is a need to be able to design a solar-energy system that considers the fluctuations in the levels of solar irradiation. A solar-energy system consists of two parts: the solar-thermal and power-generation parts. However, current designs address this concern only as it relates to the power-generation part, while the solar-thermal part is designed assuming constant conditions, such that the overall design of the solar-energy system is sub-optimal. In this paper, a novel overall design procedure is proposed for a solar-energy system, which simultaneously considers the solar-thermal and power-generation parts. This design combines the off-design performance of the power-generation part and the overall design parameters for the solar-energy system. In addition, a solar steam plant (SSP) and solar-organic Rankine cycle (SORC) were integrated with the reactive distillation column (RD) and vapor recompression technology assisted RD (VRC-RD) in the methyl acetate hydrolysis process. Actual hourly solar fluctuation data for Islamabad were selected as typical conditions for synthesising the design optimisation of the solar-energy systems. The results showed that this robust design optimisation produced a large real reduction in the total annual cost (TAC) when considering the optimisation of the solar-thermal part under real conditions; in particular, the optimised performance of the SORC with toluene as the working fluid can realise a reduction in the TAC of 42.05%. In addition, with comprehensive optimisation, the SORC with toluene proved to offer the best performance of three working fluid alternatives and realised the largest TAC for an SSP scheme (46.7%). Consideration of the off-design performance in the design of the solar-thermal part also occupied a vital position.