Hydrothermal liquefaction of kraft lignin in sub-critical water: the influence of the sodium and potassium fraction
Hydrothermal liquefaction of kraft lignin in sub-critical water: the influence of the sodium and potassium fraction
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DOI：
10.1007/s13399-018-0307-9
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发表时间：
2018-09-01
影响因子：
4
通讯作者：
Vamling, Lennart
中科院分区：
文献类型：
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作者：
Belkheiri, Tallal;Andersson, Sven-Ingvar;Vamling, Lennart
作为开发水热液化（HTL）工艺来提高木质素价值的一部分，重要的是要考虑与现有基础设施整合的可能性，以获得总体积极的经济影响。一个明显的例子是将 HTL 工艺与牛皮纸制浆厂集成：运输和存储成本降低，工艺流的温度水平可以匹配（能量集成），并且可以提高碱的回收/使用效率。在本研究中，使用亚临界水（623 K；25 MPa）在连续小型中试装置中以 2 kg/h 的流量解聚软木牛皮纸木质素。以ZrO2、K2CO3/KOH、Na2CO3/NaOH为催化体系，苯酚为封端剂。研究了进料中钠和钾的比例对产物流的产率和组成的影响。结果表明，催化体系从钾转变为钠，生物油、水溶性有机物（WSO）和焦炭产量没有受到显着影响。此外，当进料中钠含量变化时，大多数酚类化合物的产率没有显着变化。然而，当进料中钠含量增加时，所产生的生物油中的悬浮固体量显示出减少趋势（从 10.8% 减少至 3.8%），而重油则观察到相反的趋势，从 24.6% 增加至 37.6%。
As a part of developing a hydrothermal liquefaction (HTL) process to valorise lignin, it is important to consider integration possibilities with existing infrastructures in order to obtain an overall positive economic impact. One obvious example is to integrate the HTL process with the kraft pulp mill: transport and storage costs is reduced, the temperature levels on process streams can be matched (energy integration) and the recovery/use of alkali can be made efficient. In this study, softwood kraft lignin was depolymerised using sub-critical water (623 K; 25 MPa) in a continuous, small pilot unit with a flow rate of 2 kg/h. ZrO2, K2CO3/KOH and Na2CO3/NaOH were used as catalytic system, and phenol as the capping agent. The influence of the ratio between sodium and potassium in the feed on the yield and composition of the product stream was investigated. The results showed that bio-oil, water-soluble organics (WSO) and char yields were not remarkably influenced by shifting the catalytic system from potassium to sodium. Moreover, the yields of most phenolic compounds did not change significantly when the sodium fraction was varied in the feed. The amounts of suspended solids in the bio-oil produced showed, however, a diminishing trend, (decrease from 10.8 to 3.8%) when the sodium fraction was increased in the feed, whilst the opposite trend was observed for the heavy oil, which increased from 24.6 to 37.6%.