钒酸盐化合物热稳定性研究

STUDY ON THERMAL STABILITY OF VANADATE

寻找能与钒形成高熔点钒酸盐的固钒组分是开发抗钒催化裂化催化剂的关键步骤。采用DTA法考察了偏钒酸铵 (NH4VO3 )与 2 2种化合物于 6 80℃焙烧 4h后二组分混合体系的相变温度。在此基础上挑选出相变吸热峰温度在 75 0℃以上的磷、锑、锆、铬、锰、锌、镧、铈等 8种元素 ,考察其在与铝和钒共存的三组分体系中于 6 80℃焙烧 4h后的相变情况。实验结果表明 ,磷、锑、镉、锰、锌、镧、铈等 7种元素在与铝和钒共存的三组分体系中 ,其相变吸热峰的温度均在 75 0℃以上 ,故可预期在催化裂化再生温度下可能具有固定钒的能力。

V resistant components of high melting point as references for developing V resistant FCC catalyst were prepared by metal compounds incorporated with ammonium metalvanadate (NH 4VO 3).Two component systems composed of NH 4VO 3 and one of the 22 elements selected from the periodic table of elements were calcined at 680?℃ in air for 4 h then analysed by differential thermal analysis (DTA) to observe the phase transition temperature on the profile. Eight systems containing P,Sb,Zr,Cr,Mn,Zn,La and Ce were screened out by DTA,whose phase transition temperatures were all higher than 750?℃.Alumina was then introduced,together with vanadium and other selected elements to from eight 3 component systems followed by DTA study after calcination at 680?℃ in air for 4 h.Finally,seven 3 component systems containing P,Sb,Cr,Mn,Zn,La and Ce were selected out with their phase transition temperature higher than 750?℃.Those 7 elements are expected to have good vanadium captive ability under of high temperature for FCC catalyst regeneration.