New research progress on needle coke:From raw materials to preparation methods
ZHENG Xiankang;QIN Zhihong;YANG Xiaoqin;LIN Zhe
针状焦作为煤炭和石油工业的高附加值产品,是生产超高功率石墨电极的必备原料,需求与日俱增。由于对针状焦生产过程的认识不够深入,国内尚未做到大规模生产高质量针状焦。近年来,研究转向通过各种方式对原料进行改性,以扩大原料选取范围,改善原料性质,从而生产优质针状焦。综述了原料中不同成分和结构对针状焦制备过程的作用与影响,总结了针状焦生产所需的原料性质与组成要求。好的原料应具有低喹啉不溶物、低杂原子含量和高芳香族含量,反应性适中。通过原料预处理可有效改善原料组成,去除对中间相形成有害的组分。多种原料预处理方法组合使用效果好于单一预处理方法,提前热处理可以减少小分子化合物对后续反应的影响。共炭化方法是最常用的制备方法之一,在3类共炭化剂中,引导成核剂可以在中间相小球体形成过程中起晶核作用,促进中间相的形成,但也可能会引入无法被同化的杂质;缩聚催化剂可以大大缩短反应所需时间,但不利于控制反应稳定有序进行,且难以将催化剂从产品中去除;原料改性剂可以通过优化原料组成的方式改善针状焦产品性能的同时降低产品成本,是工业生产中最具有使用前景的共炭化方法。由萃取反萃取法分离获得的煤密中质组(DMC)是炼焦煤生成中间相小球体的源质,作为一种全新的原料,具有低灰分、低喹啉不溶物含量、高氢碳比等诸多优点,且无需经过预处理过程,是制备针状焦的优质原料,其制备出的中间相与针状焦均具有优良的性能。
Needle coke, as a high value-added product in the coal and petroleum industries, is an essential raw material for producing ultra-high-power graphite electrodes, and its domestic demand is increasing. Due to the lack of in-depth understanding of the production process of needle coke, high-quality needle coke has not yet been produced on a large scale in China. In recent years, more and more researchers have turned their attention to modifying raw materials through various methods to expand the selection range of raw materials and improve their properties, thereby producing high-quality needle coke. In this paper, the effects of different component and structure in raw materials on the preparation of needle coke were reviewed, and the requirements of composition and properties for raw materials were summarized. Good raw materials should have low quinoline-insoluble, low impurity atom content, and high aromatic content, while also having moderate reactivity. The pretreatment can effectively improve the composition of raw materials and remove the components which are harmful to the formation of mesophase. By comparison, the combination of multiple pretreatment methods can get better effect than single pretreatment method, pre-heating can reduce the impact of small molecular compounds on subsequent reactions. Co-carbonization method is the most commonly used preparation method. Among the three co-carbonization agents, the nucleation-induced agents can play a nucleus role in the formation of mesophase spheres and promote the formation of mesophase, but may introduce impurities that cannot be assimilated. Polycondensation catalysts can greatly shorten the reaction time, but are not conducive to controlling the reaction in a stable and difficult to be removed from the product. Raw material modifiers can improve the performance of needle coke products and reduce the cost by optimizing the composition of raw materials, which has the best application prospect in industrial production. Coal dense medium component (DMC) separated by extraction and back-extraction method is the origin substance to form mesophase in coking coals. As a new high-quality raw material for needle coke producing, DMC has many advantages such as low ash content, low quinoline insoluble content, high hydrogen carbon ratio, and not require further pretreatment process. The mesophase and needle coke prepared from DMC have excellent performances.
needle coke;mesophase;pretreatment;co-carbonization;raw material modifier
0 引言
1 原料组成与结构的影响
1.1 原料组成的影响
1.2 喹啉不溶物的影响
1.3 原料微观结构的影响
2 原料预处理方法
3 共炭化法制备针状焦
3.1 原料改性剂
3.2 引导成核剂
3.3 缩聚催化剂
4 煤特性族组分制备针状焦
5 结语与展望
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会