Flexible design of renewable methanol production systems based on regulation strategy of operating windows

Carbon dioxide hydrogenation to methanol is one of the viable ways for large-scale consumption of renewable energy. The intermittent and stochastic character of renewable energy leads to frequent changes in the operating conditions of production systems. Conventional design that focuses on the economic performance leads to rigid operating conditions and narrow operating windows of the production systems, which make it difficult to adapt to frequent changes in production capacity. It is imperative to expand the operating window of the renewable methanol production systems (RMPS) to adapt to the frequent changes in production capacity. In this work, the flexible design and regulation strategies for the RMPS are proposed, which expand the operating windows of the production systems at a low capital investment by quantitatively analyzing the relationships between process parameters and operating constraints of key equipment. The results indicate that, compared to economically optimized production systems, the proposed design method broadens the operating window of the RMPS by 54.02% with only a 22.38% increase in investment cost. The operating window can further be expanded by 113.29% with the addition of small-scale equipment at the investment cost increasing by 117.02%. The effectiveness of the proposed method and strategies is analyzed and discussed through specific application scenarios. The proposed approach improves the flexibility of the RMPS, providing an analytical basis for the flexible design and operation of chemical production systems driven by renewable energy.