煤与塑料低温共焦化的半焦光学组织研究

STUDY ON THE OPTICAL TEXTURES OF THE
SEMI-COKES FROM LOW-TEMPERATURE
CO-CARBONIZATION BETWEEN COAL AND PLASTICS

Li Wen Tian Fujun and Li Baoqing
(State Key Laboratory of Coal Conversion, Institute of Coal Chemistry,
Chinese Academy of Sciences, 030001 Taiyuan)

　　ABSTRACT　The semi-cokes from low temperature co-carbonization between different plastics (HDPE,PP,PS,PPVC) and coal, as well as the pyrolysis process of pure plastics, were analyzed using PLM. The results show that the large size anistropic texture in the semi-coke increase with the addition of plastics with the orders of HDPE＞PP＞PS＞PPVC; however, it doesn't change the characteristic texture mainly containing the mosaic ones; The improvement of anisotropic texture in the semi-coke results from the increase of the quantity and fluidity of metaplast due to the addition of plastics.
　　KEY WORDS　plastics, coal， low-temperature co-carbonization, semi-coke, PLM

　　0　引言

　　由塑料利用引起的白色污染已成为世界性的难题.关于处理废塑料的研究已引起各国学者的高度重视.废塑料和煤共焦化由于不需要增加设备投资，使得该工艺具有良好的工艺应用前景.^［1］焦炭的质量是判断该工艺成功与否的重要指标.许多研究^［2～4］发现半焦的光学组织同焦炭强度间存在密切关系：优质的冶金焦中应含有一定量的光学各向异性织构，其中以粗粒镶嵌型为主，辅以细粒镶嵌型、流线状组织及少量的域状组织.目前国内外关于废塑料与煤共焦化时半焦光学组织的变化未见报道.本文利用偏光显微镜对半焦进行冷态显微观察，结合单种纯塑料的热态显微分析，研究了塑料的添加对煤热解半焦的影响.

　　1　实验部分

　　1.1　原料及性质
　　所用聚乙烯(PE)、聚丙烯(PP)、聚苯乙烯(PS)、脱氯聚氯乙烯(PPVC)均由太原塑料公司提供，实验选用山东枣庄八一焦煤(1/3焦煤)，其性质见表1.

表1　煤的性质分析
Table 1　Analysis of coal sample

图1　八一焦煤半焦的光学显微照片
Fig.1　The optical photograph of semi-coke of
Bayi coking coal

图2　塑料与煤低温共焦化半焦的光学显微照片
Fig.2　The optical photograph of semi-coke from
low-temperature co-carbonization between coal and plastics
(a)——Addition of 5% HDPE;(b)——Addition of 5% PP;
(c)——Addition of 5% PPVC; (d)——Addition of 5% PS

图3　PP热态显微照片
Fig.3　The thermal optical photograph of PP
(a)——Room temp.；(b)——160℃；(c)——220℃；(d)——450℃；(e)——600℃

图4　HDPE热态显微照片
Fig.4　The thermal optical photograph of HDPE
(a)——Room temp.；(b)——220℃；(c)——450℃；
(d)——600℃

图5　PPVC热态显微照片
Fig.5　The thermal optical photograph of PPVC
(a)——Room temp.；(b)——460℃；(c)——520℃；
(d)——600℃