化学反应工程与工艺
化學反應工程與工藝
화학반응공정여공예
CHEMICAL REACTION ENGINEERING AND TECHNOLOGY
2014年
2期
133-139
,共7页
郭宏利%李经球%李华英%孔德金
郭宏利%李經毬%李華英%孔德金
곽굉리%리경구%리화영%공덕금
甲苯%重芳烃%歧化%烷基转移%钯%双金属催化剂
甲苯%重芳烴%歧化%烷基轉移%鈀%雙金屬催化劑
갑분%중방경%기화%완기전이%파%쌍금속최화제
toluene%heavy aromatics%disproportional%transalkylation%palladium%bimetal catalyst
为提高甲苯歧化与烷基转移生成苯和二甲苯反应的收率，采用了ZSM-12分子筛负载钯和铅的双金属甲苯歧化与烷基转移催化剂，在连续操作的小型固定床反应器中考察了钯金属负载量、钯-铅物质的量比、反应条件对反应性能的影响。结果表明：引入钯金属能提高重芳烃转化率，同时也加剧了苯环加氢副反应；适当降低钯金属负载量、采用钯-铅双金属体系能有效抑制芳烃加氢副反应，优化催化剂整体反应性能；提高反应温度、降低氢气纯度及反应压力有利于抑制加氢副反应，改善催化剂反应性能。基于钯含量为0.2%，Pb/Pd比为3的双金属催化剂体系，在原料组成苯与碳九及其以上重芳烃的质量比为30：70，反应温度390℃，反应压力2.5 MPa,进料空速4.0 h-1，氢烃比2.0的较佳条件下，甲苯的转化率为21.7%，重芳烃转化率61.6%，二甲苯的质量收率达36.2%，苯的纯度为99.5%，表现出了较高的重芳烃处理能力及二甲苯收率。
為提高甲苯歧化與烷基轉移生成苯和二甲苯反應的收率，採用瞭ZSM-12分子篩負載鈀和鉛的雙金屬甲苯歧化與烷基轉移催化劑，在連續操作的小型固定床反應器中攷察瞭鈀金屬負載量、鈀-鉛物質的量比、反應條件對反應性能的影響。結果錶明：引入鈀金屬能提高重芳烴轉化率，同時也加劇瞭苯環加氫副反應；適噹降低鈀金屬負載量、採用鈀-鉛雙金屬體繫能有效抑製芳烴加氫副反應，優化催化劑整體反應性能；提高反應溫度、降低氫氣純度及反應壓力有利于抑製加氫副反應，改善催化劑反應性能。基于鈀含量為0.2%，Pb/Pd比為3的雙金屬催化劑體繫，在原料組成苯與碳九及其以上重芳烴的質量比為30：70，反應溫度390℃，反應壓力2.5 MPa,進料空速4.0 h-1，氫烴比2.0的較佳條件下，甲苯的轉化率為21.7%，重芳烴轉化率61.6%，二甲苯的質量收率達36.2%，苯的純度為99.5%，錶現齣瞭較高的重芳烴處理能力及二甲苯收率。
위제고갑분기화여완기전이생성분화이갑분반응적수솔，채용료ZSM-12분자사부재파화연적쌍금속갑분기화여완기전이최화제，재련속조작적소형고정상반응기중고찰료파금속부재량、파-연물질적량비、반응조건대반응성능적영향。결과표명：인입파금속능제고중방경전화솔，동시야가극료분배가경부반응；괄당강저파금속부재량、채용파-연쌍금속체계능유효억제방경가경부반응，우화최화제정체반응성능；제고반응온도、강저경기순도급반응압력유리우억제가경부반응，개선최화제반응성능。기우파함량위0.2%，Pb/Pd비위3적쌍금속최화제체계，재원료조성분여탄구급기이상중방경적질량비위30：70，반응온도390℃，반응압력2.5 MPa,진료공속4.0 h-1，경경비2.0적교가조건하，갑분적전화솔위21.7%，중방경전화솔61.6%，이갑분적질량수솔체36.2%，분적순도위99.5%，표현출료교고적중방경처리능력급이갑분수솔。
Pd-Pb/ZSM-12 catalysts were applied in disproportionation and transalkylation of toluene with heavy aromatics to increase xylenes product yield. The effect of loading Pd, the molar ratio of Pb to Pd and reaction conditions on catalyst performances were investigated in a continuous operation miniature fixed bed reactor. The results show that addition of Pd can improve heavy aromatics conversion, but also cause hydrogenation of aromatic ring. Addition of Pb to a low Pd content catalyst is effective to reduce aromatic ring hydrogenation and maintain high xylenes yield. Furthermore, the reaction conditions of high reaction temperature, low hydrogen pressure and hydrogen purity were favorable to reduce aromatic ring hydrogenation to obtain higher product purity. The optimized bimetallic catalyst containing 0.2%Pd metal and certain amount of Pb metal (molar ratio of Pb to Pd is 3) was used to catalyze the reaction under favorable reaction conditions of reaction temperature of 390 ℃, reaction pressure of 2.5 MPa, feed space velocity of 4.0 h-1 and hydrogen/hydrocarbon ratio of 2.0 with a feedstock containing 30%toluene and 70%heavy aromatics. The conversion of toluene and heavy aromatics was 21.7%and 36.2%respectively and the product purity of benzene reached 99.5%, which exhibits improved performance on enhancing heavy aromatic conversion and xylenes yield.
