Abstract:
Aiming at the “Dual Carbon” goals, the greeization of a coal to 1,3-propylene glycol (PDO) production process is of great significance for promoting the low-carbon transition of the coal chemical industry. This study establishes a green production process based on coal-based PDO and investigates the differences between the use of renewable raw materials-such as hydrogen production via water electrolysis, CO
2 conversion to CO, and CO
2 hydrogenation to methanol-and the traditional coal-based PDO production process. The study focuses on analyzing the impact of green technologies, including green hydrogen, green electricity, and green steam, on the carbon emissions of the PDO production process. A comparative analysis of carbon emissions under different scenarios indicates that the carbon emissions of the traditional coal-based PDO production process amount to 527.34 kt/a. By adopting the green synthesis process, emissions are significantly reduced to 382.14 kt/a, accounting for only 72.5% of the traditional process, demonstrating the inherent emission reduction benefits of the green process. The introduction of green electricity further reduces emissions to 307.73 kt/a achieving an additional reduction of 74.41 kt/a compared to the green synthesis process, highlighting the positive role of green electricity in carbon reduction. The most significant reduction is observed in the scenario combining green electricity and green steam, where emissions drop to 114.49 kt/a - only 21.7% of the emissions from the traditional production process - representing a total reduction of 412.85 kt/a. Among all production units, the methyl 3-hydroxypropionate synthesis unit contributes the highest proportion of carbon emissions, primarily due to steam consumption. However, in the green process scenario, the introduction of green steam can significantly reduce emissions from this unit. Additionally, ethylene consumption in the PDO green production process is the major contributor to carbon emissions, accounting for more than 88.6%. Therefore, future efforts should focus on exploring low-carbon alternatives for ethylene feedstock to further reduce the overall carbon footprint of PDO production.