Heat Transfer Limitations in Supercritical Water Gasification

Energies

Francisco JavierGutiérrez Ortiz¹  Francisco López-Guirao¹  Francisco José Jiménez-Espadafor²  José Manuel Benjumea² 

[1] Department of Chemical and Environmental Engineering, Escuela Técnica Superior de Ingeniería, Universidad de Sevilla, Camino de los Descubrimientos s/n, 41092 Sevilla, Spain;Department of Energy Engineering, Escuela Técnica Superior de Ingeniería, Universidad de Sevilla, Camino de los Descubrimientos s/n, 41092 Sevilla, Spain;

关键词: supercritical water;    gasification;    reforming;    heat transfer;    tubular reactor;    heating rate;   

DOI  :  10.3390/en15010177

来源: DOAJ

【 摘 要 】

Supercritical water gasification (SCWG) is a promising technology for the valorization of wet biomass with a high-water content, which has attracted increasing interest. Many experimental studies have been carried out using conventional heating equipment at lab scale, where researchers try to obtain insight into the process. However, heat transfer from the energy source to the fluid stream entering the reactor may be ineffective, so slow heating occurs that produces a series of undesirable reactions, especially char formation and tar formation. This paper reviews the limitations due to different factors affecting heat transfer, such as low Reynolds numbers or laminar flow regimes, unknown real fluid temperature as this is usually measured on the tubing surface, the strong change in physical properties of water from subcritical to supercritical that boosts a deterioration in heat transfer, and the insufficient mixing, among others. In addition, some troubleshooting and new perspectives in the design of efficient and effective devices are described and proposed to enhance heat transfer, which is an essential aspect in the experimental studies of SCWG to move it forward to a larger scale.

【 授权许可】

Unknown