煤焦着火点与其气化活性的关系

THE RELATIONSHIP BETWEEN GASIFICATION REACTIONRATES OF CHARS AND THEIR IGNITION POINTSTEMPERETURES

煤气化的活性是一个极重要的工艺指标,它对煤的燃烧,特别是煤的气化有明显的影响。通常用煤或煤焦在相同条件下的气化比反应速率(或速度常数)来比较煤的活性。在我国则广泛采用煤或煤焦和二氧化碳反应后二氧化碳的转化百分数作为相对活性的评价指标。对于放热的煤或煤焦的燃烧反应来说,可以测出煤焦的着火温度,着火温度高低也应该和相对活性有一定的关系。因此,阐明它们之间的关系是很有价值的。测定反应速率有时较困难,有时又很耗费时间,若能用快速的测定着火温度方法来表示其相对活性,其实用意义是明显的。文献中已有根据这种设想来研究煤的催化燃烧或放热的催化反应的报导。还提出以煤炭的着火温度作为煤炭反应性的表示方法之一。

Partial gasification of Wandoan chars with carbon dioxide were carried out in a fluidized bed reactor at normal pressure and 850℃.Reaction rates of these chars and their demineralized products with carbon dioxide at normal pressure and 800℃ as well as their ignition temperatures in oxygen were determined.It has been found that reactivities of both chars and their demineralized products decrease with increasing conversion,while their ignition temperatures increase with increasing conversion,and there is a good correlation between ignition temperatures and initial reaction rates.It is suggested that the ignition temperatures of chars determined in certain condition can be used to some extent to characterize the relative reactirities.