The temperature and pressure of the hydrothermal process occurring in a batch reactor are typically coupled. Herein, we develop a decoupled temperature and pressure hydrothermal system that can heat the cellulose at a constant pressure, thus lowering the degradation temperature of cellulose significantly and enabling the fast production of carbon sub-micron spheres. Carbon sub-micron spheres can be produced without any isothermal time, much faster compared to the conventional hydrothermal process. High-pressure water can help to cleave the hydrogen bonds in cellulose and facilitate dehydration reactions, thus promoting cellulose carbonization at low temperatures. A life cycle assessment based on a conceptual biorefinery design reveals that this technology leads to a substantial reduction in carbon emissions when hydrochar replacing fuel or used for soil amendment. Overall, the decoupled temperature and pressure hydrothermal treatment in this study provides a promising method to produce sustainable carbon materials from cellulose with a carbon-negative effect.

在间歇反应器中发生的水热过程的温度和压力通常是耦合的。在此，我们开发了一种温度和压力解耦的水热系统，可以在恒定压力下加热纤维素，从而显着降低纤维素的降解温度，并能够快速生产碳亚微米球。无需任何等温时间即可生产碳亚微米球，与传统的水热工艺相比要快得多。高压水有助于裂解纤维素中的氢键，促进脱水反应，从而促进纤维素在低温下碳化。基于概念性生物精炼厂设计的生命周期评估表明，当水炭替代燃料或用于土壤改良时，该技术可显着减少碳排放。总体而言，本研究中的温度和压力解耦水热处理为从纤维素生产具有碳负效应的可持续碳材料提供了一种有前景的方法。