摘要
分析催化裂化过程中焦炭的生成及其对催化剂性能的影响,焦炭的生成与芳烃和烯烃等不饱和分子烃的环化、氢转移、烷基化以及缩合反应密切相关,在反应初期,焦炭产率处于较低水平且增幅不大,主要来自多环芳烃吸附焦;随着反应深度的增加,焦炭产率明显增加继而急剧增加,主要来自催化反应生成焦及对焦炭前驱物的吸附。焦炭对催化剂性能的影响主要表现在孔道堵塞和酸中心毒害,焦炭主要沉积在分子筛外表面或孔口处,使反应物分子不能进入孔内;残留在再生催化剂上的少量焦炭主要位于分子筛内,导致催化剂比表面积、孔体积和酸量的大量损失。基于以上分析,提出降低催化裂化焦炭的一些措施,为开发低焦炭产率的催化裂化催化剂和工艺提供依据。
The formation of coke and its effect on the performance of catalyst in FCC were analyzed.The formation of coke is closely related to the cyclization,hydrogen transfer,alkylation and condensation of unsaturated molecular hydrocarbons such as aromatics and olefins.At the initial stage of FCC process,the coke yield is at a low level and the increase is not significant,which is mainly from the adsorption coke of polycyclic aromatic hydrocarbons;With the increase of reaction depth,the coke yield increases obviously and then increases sharply,which mainly comes from the coke formed in catalytic reaction and the adsorption of coke precursors.The effect of coke on the performance of catalyst is mainly manifested in pore plugging and acid center poisoning.Coke is mainly deposited on the outer surface of the zeolites or at the pore openning,so that the reactant molecules cannot approach the acid site inside pore.A small amount of coke remained on regenerated catalyst is mainly located in zeolites,which leads to a large loss of specific surface area,pore volume and acid content of catalyst.Based on above analysis,some measures to reduce FCC coke are put forward,which can provide basis for developing FCC catalyst and process with low coke yield.
作者
于善青
舒春溪
李家兴
林伟
Yu Shanqing;Shu Chunxi;Li Jiaxing;Lin Wei(SINOPEC Research Institute of Petroleum Processing,Beijing 100083,China)
出处
《工业催化》
CAS
2020年第10期9-18,共10页
Industrial Catalysis
基金
国家重点研发计划(2017YFB0306504)。
关键词
石油化学工程
催化裂化催化剂
焦炭
芳烃
氢转移
petrochemical engineering
catalytic cracking catalyst
coke
aromatics
hydrogen transfer
