直馏柴油催化裂解和热裂解反应行为研究

以直馏柴油为原料，反应温度为520～680 ℃，在小型固定流化床上分别采用酸性催化剂和石英砂，考察催化裂解和热裂解的反应行为。与热裂解相比，直馏柴油催化裂解提高了其转化率，降低了干气产率，提高了液化气产率；乙烯产率降低1.67～3.78百分点，丙烯产率提高5.23～9.12百分点，丁烯产率提高3.32～7.94百分点，轻芳烃（BTX）产率接近。直馏柴油催化裂解和热裂解干气中的甲烷和乙烯含量随反应温度变化的趋势相同，但是催化裂解干气中氢气体积分数高于乙烷，而热裂解干气中乙烷体积分数高于氢气；反应温度高于600 ℃时，催化裂解干气中C2H4/CH4摩尔比小于热裂解干气的最优分布值0.82。两种裂解汽油烃类组成中正构烷烃、异构烷烃、烯烃和芳烃含量变化趋势相同，而环烷烃含量变化趋势相反；催化裂解汽油中环烷烃含量随反应温度升高而降低，而热裂解汽油中环烷烃含量随反应温度升高而增加。

REACTION BEHAVIOR OF ATMOSPHERIC GAS OIL DURING CATALYTIC CRACKING AND THERMAL CRACKING

The catalytic cracking and thermal cracking reactions of atmospheric gas oil（AGO）were investigated in a small fixed fluidized bed reactor at 520－680 °C using acid catalyst and quartz sand respectively. Compared with thermal cracking, the catalytic cracking of AGO had the advantages in increasing its conversion, decreasing the dry gas yield and increasing the LPG yield, which could reduce the ethylene yield by 1.67－3.78 percentage points, increase propylene yield by 5.23－9.12 percentage points and the butene yield by 3.32－7.94 percentage points respectively, so as to the BTX yield. The content of methane and ethylene in the dry gas of catalytic cracking and thermal cracking of AGO had the same change trend with reaction temperature, but the volume fraction of hydrogen in catalytic cracking dry gas was greater than ethane, while the volume fraction of hydrogen in thermal cracking dry gas was lower than ethane. When the reaction temperature was higher than 600 ℃, the mole ratio of C2H4/CH4 of catalytic cracking dry gas was less than the optimal distribution value of thermal cracking dry gas（0.82）. The changing trends of n-alkane, isoalkane, olefin and aromatic in the two kinds of cracking gasoline were similar, but the changing trend of naphthene was opposite. The naphthene in catalytic cracking gasoline decreased with the increase of reaction temperature, while the naphthene in thermal cracking gasoline increased with the increase of reaction temperature.