配煤制备高比表面煤基活性炭的研究_邵景景

中文摘要

高比表面积活性炭由于具有发达的微孔结构和大的吸附容量，被广泛用于燃料气储存、气体分离、超级电容器、催化反应等方面。黑龙江省作为煤炭大省，其丰富的煤炭资源为活性炭产业的发展提供了有利的条件。

本研究以黑龙江三种不同煤种七台河煤、依兰煤和鸡西煤为原料，运用正交实验方法，采用KOH化学活化法在氮气保护下制备高比表面积活性炭，以所得活性炭的碘吸附值为考察指标，比较三种煤制备活性炭的优劣并确定最佳工艺条件。结果表明：经酸洗脱灰的七台河煤，活化温度850℃，炭活化时间120 min，碱炭比5/1为最佳实验条件。在此条件下所得活性炭的碘吸附值已达1946 mg·g-1，比表面达到1721 m2·g-1。

将七台河煤与依兰煤进行配煤实验研究，结果表明：七台河煤与依兰煤配比1/1，碱炭比6/1，活化温度850℃，炭活化时间120 min时活性炭的吸附性能最佳。其主要影响因素依次为原料煤配比、碱炭比、活化温度和炭活化时间。在此条件下所得活性炭的碘吸附值可达1973 mg·g-1，比表面达1735 m2·g-1。

以KOH为活化剂，配煤活化反应速率在800~950℃范围内，对烧失率B为一级反应，由阿仑尼乌斯公式可求出反应活化能为101.4032 kJ·mol-1，指前因子为3.1382×104。配煤制活性炭对苯酚吸附符合Freundlich吸附等温模型，其对苯酚的吸附量随温度的升高而下降，吸附热力学参数△H为-9.6108 kJ·mol-1，△S为-20.0541 J·mol-1·K-1，△G均为负值；其对苯酚的吸附符合二级吸附动力学模型，吸附速率常数k2为1.9515×10-2 g·mg-1·min-1。

关键词：高比表面活性炭；炭活化反应；配煤

Abstract

HSAAC(high surface area activated carbon) is widely used in fuel gas storage, gas separation, catalysis and various chemical processes, because of having more micro-porous and high absorption capacity. As a major coal province of Heilongjiang, rich coal resources for the development of activated carbon industry has provided favorable conditions.

In this disquisition, HSAAC were prepared by KOH activation and N2 protection with orthogonal design from three typical coals of Heilongjiang which were Qitaihe coal, Yilan coal and Jixi coal. The optimum technics conditions were determined by adsorption value of I2. The results was indicated that，the activated carbon of which the absorption value of I2 and BET surface area respectively reached up to 1946 mg·g-1 and 1721 m2·g-1 above, was prepared by Qitaihe anthracite pretreated under the experimental conditions of activated temperature of 850℃, activated time of 120min and ratio of alkali/carbon of 5/1.

Blending coal study of Qitaihe and Yilan coal was also done at the same time, The results showed that the best experiment condition was the two type of coals as 1/1 ratio mixture, ratio of alkali/carbon of 6/1, activated temperature of 850℃, activated time of 120min. The main influence factors in order were the ratio of coal, ratio of alkali/carbon, activated temperature and activated time. On this condition the absorption value of I2 and BET surface area respectively reached up to 1973mg·g-1 and 1735 m2·g-1.

The results also show the reaction rate of burn-off B is first-order reaction used KOH in 800~950℃. According to Arrhenius equation, it is calculated that the apparent activation energy of carbonization-activation reaction is 101.4032 kJ·mol-1, and the pre-exponential factor is 3.1382×104. The adsorption equilibrium of phenol onto