Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7705317 | International Journal of Hydrogen Energy | 2018 | 10 Pages |
Abstract
Supercritical water gasification (SCWG) is a promising innovative black liquor handling method. The low concentration of black liquor is a burden for the system scale and investment cost. In this study, we introduced black liquor evaporator to increase the concentration using self-generated steam and power, and studied its influence on the energy and exergy efficiency. The results showed that increasing black liquor concentration from 10Â wt% to 20Â wt% reduced the energy efficiency but increased the exergy efficiency of the system without evaporator. With the evaporator, an optimal target concentration existed for the exergy efficiency owing to the influence of the target concentration on the balance between the energy consumption and saving brought by the evaporator. With black liquor condensed from 15Â wt% to 21.82Â wt%, maximum exergy efficiency of the system (41.95%) was obtained. For lower-concentration black liquor, more water needs to be evaporated to get the optimal concentration and evaporator was more desired because it brought greater improvement on the exergy efficiency. The increasing effect number of multi-effect evaporator shifted the optimal concentration to higher values, which increased from 19.93Â wt% to 23.13Â wt% when the effect number increased from 4 to 7. The exergy efficiency of the system was also improved, and the improvement was more significant at higher target concentration.
Related Topics
Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
Changqing Cao, Youyou He, Jia Chen, Wen Cao, Hui Jin,