CAJ | 학술논문

作为玉米生产加工过程的农业废弃物,玉米芯的产量巨大,生物质气化工业利用玉米芯原料制备生物质燃气的过程中将产生大量的玉米芯灰.为了全面认识这些废弃玉米芯灰的灰特性及可能的应用,通过激光粒度分析、X射线荧光(X-ray fluorescence,XRF)、X射线衍射(X-ray diffraction,XRD)、热重和差热分析(thermal gravimetric and differential thermal analysis,TG-DTA)、扫描电镜(scanning electron microscopy,SEM)、能谱分析(energy dispersive X-ray,EDX)等方法对其进行深入研究.结果表明:玉米芯灰的粒度较小且分布不均,平均粒径为 12.96 μm;灰的元素组成中 K 和Si所占的比重最大;富含K、Ca、S和Cl等元素使玉米芯灰可用作土壤改良剂,而且灰中大量的SiO2和Al2O3使其可以用来制备抗压强度较高的水泥混凝土;灰中存在多种含钾元素的KHCO3、KAlSiO4、KAlSi2O6、KCl和K2SO4等结晶相矿物成分;灰粒的形状极不规则,树枝状的团聚灰渣具有丰富的空隙,易逐级吸附小颗粒,灰粒表面存在大量弱粘结的絮状物,断面多为孔状结构;熔融灰粒表面存在富钾现象,且多以KCl形式存在;飞灰的热解具有分段机制,加热到1 200℃时,其总失重和最大失重速率均随着氧气浓度的升高而增加;氮气中620℃的吸热峰是由KCl熔融吸热所致,而有氧气氛中在630℃处的放热峰则是未燃尽的残碳继续燃烧或有机物分解放热所致.
작위옥미생산가공과정적농업폐기물,옥미심적산량거대,생물질기화공업이용옥미심원료제비생물질연기적과정중장산생대량적옥미심회.위료전면인식저사폐기옥미심회적회특성급가능적응용,통과격광립도분석、X사선형광(X-ray fluorescence,XRF)、X사선연사(X-ray diffraction,XRD)、열중화차열분석(thermal gravimetric and differential thermal analysis,TG-DTA)、소묘전경(scanning electron microscopy,SEM)、능보분석(energy dispersive X-ray,EDX)등방법대기진행심입연구.결과표명:옥미심회적립도교소차분포불균,평균립경위 12.96 μm;회적원소조성중 K 화Si소점적비중최대;부함K、Ca、S화Cl등원소사옥미심회가용작토양개량제,이차회중대량적SiO2화Al2O3사기가이용래제비항압강도교고적수니혼응토;회중존재다충함갑원소적KHCO3、KAlSiO4、KAlSi2O6、KCl화K2SO4등결정상광물성분;회립적형상겁불규칙,수지상적단취회사구유봉부적공극,역축급흡부소과립,회립표면존재대량약점결적서상물,단면다위공상결구;용융회립표면존재부갑현상,차다이KCl형식존재;비회적열해구유분단궤제,가열도1 200℃시,기총실중화최대실중속솔균수착양기농도적승고이증가;담기중620℃적흡열봉시유KCl용융흡열소치,이유양기분중재630℃처적방열봉칙시미연진적잔탄계속연소혹유궤물분해방열소치.
Globally, biomass resources regarded as a green renewable energy has the potential of being more important in the future, which attract worldwide attention regarding their renewable nature, carbon dioxide-neutral characteristics, and world-wide availability. Consequently, many countries are putting great emphasis on the exploration of bio-energy, and the techniques used are various such as combustion, gasification, pyrolysis, hydrogen production, and so on. As a by-product generated from the processing of corn, the production of corncob (CC) is rather abundant, and reaches up to 3.87 million tons per year in China. The biomass gasification industries make use of CC residues as raw materials for producing biomass fuel gas. However, the gasification generates tons of corncob ash (CCA) everyday, which is requiring daily disposal properly. Herein this study is focused on the preliminary properties of waste CCA to analyze how it could be transformed into eco-friendly value added products. For a broad awareness of properties and possible utilizations of these waste CCA, some techniques were used such as laser particle size analyzer (LPSA), X-ray fluorescence (XRF), X-ray diffraction (XRD), thermal gravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX). The results showed that the granularity distribution of CCA powders was very homogeneous, and the particle size analysis showed a mean diameter of 12.96μm and a medium diameter of 10.23μm. The elemental composition revealed that potassium and silicon were the most abundant elements. Being rich in potassium, calcium, sulfates and chlorine made CCA suitable for using as soil amendment and the high content of combined SiO2 and Al2O3 made it possible to be used a pozzolan in blended cement concrete. The XRD spectrogram indicated the presence of several crystalline phases in CCA. Many crystalline phase minerals containing potassium in the ash present in forms of KHCO3, KAlSiO4, KAlSi2O6, KCl and K2SO4. The SEM images revealed the ash is highly agglomerated and with irregular shapes. Those shapes of ash particles were multiple and these dendritic reunion ashes had rich interspace, which easily leaded to adsorption of small particles step-by-step. A large number of weak bonding flocs adhered to the particle surface. The fracture surface of these particles was porous. Being rich in potassium was found on the surface of molten particles, which was mainly in form of KCl. The EDX data telled us that the surface of molten particles was covered with KCl. And the water soluble salt concentrate was particularly rich in KCl, which was of interest in terms of element extraction. The thermal analysis revealed the decomposition of CCA had a stepwise mechanism, which implied a total weight loss of 17.13% under nitrogen, that of 19.86% under dry air and that of 23.12% under 40% O2 in N2when heating to 1 200. This illustrated that the mass loss increases with the rise of oxygen concentration. An endothermic peak near 620℃ in nitrogen was due to melting of KCl, while the exothermic peak at around 630℃ in the aerobic environment was caused by ignition of unburned carbon and degradation of residual organic matters. The unburnt carbon in CCA has a potential to be separated and used for activated carbon or other applications. This paper provides the baseline of future work on the possible utility of the waste CCA from biomass gasification stations.