钾盐对生物质炭氧化速率和反应热的影响

Effect of potassium salts on oxidation rate and reaction heat of biochar

为明确钾盐对生物质炭氧化过程的影响,应用同步热分析仪,对添加质量分数为0—5%KCl和K_(2)SO_(4)的玉米秸炭、松木炭以及杉木活性炭的氧化反应速率和反应热进行了分析。结果表明:钾盐对杉木炭和松木炭氧化有明显的促进作用,且促进作用随钾质量分数增加而提高,添加5%的KCl,杉木炭在550℃的氧化速率提高到原来的2.5倍,然而,钾盐对玉米秸炭氧化作用可忽略;各种质量分数的钾盐均能同样显著地将杉木炭的氧化反应热从约17.5 MJ/kg增加到约22.5 MJ/kg,但不影响玉米秸炭或松木炭的氧化反应热。这些说明钾盐对不同种类生物质炭的氧化速率和反应热的影响结果明显不同,影响机理也需进一步研究。

In order to clarify the effect of potassium salts on oxidation of biochar,oxidation rate and reaction heat of maize-stalk-char,pine-char from pyrolysis and fir-char from activated carbonization added with mass fraction 0-5% of KCl and K_(2)SO_(4) were investigated experimentally in simultaneous thermal analyzer.The results show that potassium salts significantly promote oxidation rates of fir-char and pine-char,and the promotion increases with increasing potassium contents.Oxidation rate of fir-char is increased by 2.5 times when mass fraction 5% of KCl is added.However,the effect of potassium salts on maize-stalk-char is negligible.Potassium salts significantly increase reaction heat of oxidation of fir-char from about 17.5 MJ/kg to 22.5 MJ/kg,independent on their contents,which do not affect reaction heat of oxidation of maize-stalk-char or pine-char.It is concluded that the effects of potassium salts on the oxidation rate and reaction heat are different with different biochar,and further investigation on the mechanism is necessary.