Bi_2O_3改性SiO_2涂层对环己烷超临界裂解结焦和燃烧性能的影响

Effect of SiO_2 coating modified by Bi_2O_3 on coking and combustion performance for cyclohexane pyrolysis under Supercritical Condition

为抑制碳氢燃料在微通道油道中的表面结焦并提高高温裂解产物的燃烧性能,采用负压抽涂的方法,在微通道不锈钢的内壁分别涂覆了Si O2涂层和以Si O2为载体,掺杂不同添加量Bi2O3助剂的Bi2O3-Si O2系列涂层。选用环己烷,在超临界条件下进行裂解实验,分别评价涂层的抑焦效果和对燃烧性能的影响。结果表明,Si O2涂层能够有效的抑制金属催化结焦,从而提升运行温度和时间;Bi2O3-Si O2系列涂层可以有效提高高温段时对环己烷的裂解活性和选择性,当Bi2O3添加量为10%时,涂层对烯烃的选择性最好,有利于提升裂解产物的高温燃烧性能。

In order to inhibit the metal catalytic coking and enhance the combustion performance at high temperature for hydrocarbon fuel,two kinds of materials,including Si O2 coating and Bi2O3-Si O2 coatings which are composed of Si O2 carrier material with adding different percentage compositions of Bi2O3,are coated on the inner surface of the stainless steel tube with small diameter. Then the pyrolysis experiments for cyclohexane are adopted to evaluate the effect of these coatings on the anti-coking and combustion under the supercritical condition. The results indicate that the Si O2 coating can effectively inhibit the metal catalytic coking and promote the safe running temperature and period for the cyclohexane pyrolysis at high temperature; and the series of Bi2O3-Si O2 coatings can promote the cracking activity and selectivity of the gas products at high temperature. It is discovered that,among these coatings,the Bi2O3-Si O2 coating with 10% content of Bi2O3 addition,has the best selectivity for the pyrolysis gas products and benefits the combustion performance.