玉米秸秆水热炭化预处理制备水煤浆及其成浆特性

Preparation and slurry ability of coal water slurry with hydrothermal carbonization pretreatment of corn straw

针对我国玉米秸秆产量高、利用率低的现状,探究玉米秸秆水热炭化(Hydrothermal Carbonization,HTC)预处理特性,并分析其水热炭(Hydrothermal Carbon,HC)与煤混合成浆机制。水热炭化操作温度为180、200、220、240℃,终温停留时间为60 min。结果表明:水热炭化过程以脱水和脱羰基为主,水热炭收率和能量产率随温度升高而降低,其表面形成微球颗粒,孔隙增大。选择温度为220℃水热炭(HTC-220)与神华煤混合制浆,探究第二液体煤油的修饰方式和用量(0.5%~1%)以及空气相对湿度(40%、50%、60%)对生物质水煤浆成浆性能的影响。结果表明:第二液体煤油修饰水热炭成浆的表观黏度最低,流动性最好。煤油用量为0.8%时,浆体表观黏度最低,为979.5 mPa·s,达到最佳流动状态。生物质水煤浆的表观黏度随着空气相对湿度增加而下降,这是由于空气中水分子在水热炭颗粒表面形成封孔效应,浆体自由水含量增加,成浆性能提高。

Due to the high yield and low utilization of corn straw in China,hydrothermal carbonization(HTC)pretreatment of corn straw with coal was studied to prepare hydrochar coal water slurries(HC-CWS).Using corn straw as raw material,the hydrochar(HC)was prepared by HTC at temperature of 180,200,220,240℃and time of 60 min.The results showed that HTC is a process of dehydration and deoxygenation.The yield and energy yield of HC decreased with increasing temperature.HTC resulted in the appearance of many microsphere particles on the surface of HC,which also led to the enlargement of the pore structure of HC.Mixing HTC-220 and ShenHua coal(SH),the effects of second liquid modification method and dosage and relative humidity on the slurry ability of HC-CWS was studied.The results showed that the HC-CSW had the lowest apparent viscosity and the beat fluidity when the kerosene was modified with HC.When the kerosene dosage was 0.8%,the HC-CWS had the lowest apparent viscosity and the apparent viscosity was 979.5 mPa·s.The apparent viscosity of HC-CWS decreased with the increase of relative humidity.This was due to the water molecules like“bottle stoppers”to prevent pores from being filled with water,which increased the content of free water in the HC-CWS and improved the slurry performance.