Low-Carbon Path of Geographically Matched Hybrid Energy Utilization: A Coal-To-Ethylene Glycol Process with Hydrogen from the Coupled Wind/Solar Power

Abstract

The development of the polyester industry has created a growing demand for ethylene glycol (EG). Coal-to-EG (CtEG) is an important technical route for EG production in many countries, especially China. However, due to the mismatch of hydrogen-to-carbon ratio between raw coal and products, the process is endowed with high CO₂ emission intensity and wastage of carbon sources. Taking advantage of the geographical compatibility of wind/solar energy and coal-based processes in Northern China, we propose a new CtEG process with low-carbon hydrogen from the coupling of wind/solar power (WPCtEG). Based on the system modeling and simulation, the key operating parameters were studied and a dynamic hydrogen–carbon conversion framework was proposed to offset the influence of hydrogen fluctuation and reasonably configure the process system. Compared with traditional CtEG, the carbon efficiency and exergy efficiency of WPCtEG increased by 21.2 and 7.6%, respectively. The CO₂ emission intensity of this process reduced from 2.58 to 0.93 t/t-EG, whereas the production cost saves 31 $/t-EG. With the new sustainable energy and hybrid energy integration, this new process shows the development prospects of both low-carbon and high-yield efficiency.