生物质废弃物在回转窑内热解研究--Ⅱ.热解终温对产物性质的影响

考察了不同热解终温下木块和稻壳在回转窑内热解产物－燃气、焦油和炭的成分和性质的变化。在试验温度范围内,热解气体热值约10．0－15．9MJ／Nm^3,密度1.21-1.52Nm^3/kg,且随热解终温变化呈规律性变化,木块炭的热值为29.0-33.9MJ／kg,稻壳炭则为17.6-20.8MJ/kg,热解终温的提高使炭中挥发份的降低,灰分增多,从而导致热值的降低;炭的C含量高于原始物料的C含量,而H、O则相反;元素残留率的计算表明,热解过程中H和O元素的脱除易于C元素。热解终温对焦油中饱和烃、芳香烃成分含量的影响不大,饱和链烃成分主要集中为C14－C34正构烷烃和含末端双链烯烃的碳分子链,芳香烃主要为蒽（菲）、芘、萤蒽及各自衍生物的稠环芳烃。     

热解温度对污泥热解半焦产率与特性影响的研究

利用固定床反应器对3种不同来源的污泥进行热解，研究了热解终温对污泥热解半焦产率、热值和比表面积的影响。研究结果表明：随着热解终温的提高，污泥热解半焦的产率逐渐降低；随着半焦中挥发分的减少和灰分含量的增加，半焦的热值降低；半焦的比表面积呈现先增加后降低的趋势，3种污泥在热解终温分别为900，800，700℃时获得的半焦比表面积达到最大值，分别为64．88，44．26，23．75m^2／g。     

生物质废弃物在回转窑内热解研究--Ⅰ.热解条件对热解产物分布的影响

研究了生物质类废弃物在回转窑内的热解特性,讨论了物料种类,热解终温,加热方式,给料粒径和含水率对热解产物分布的影响。物料挥发份和热解终温高,加热快,粒径小,有利于燃气产率的提高以及炭产率的降低,而水分的提高会提高焦油的产率并降低炭的产率。同时,还研究了回转窑内的温升特性和热解气体的瞬态析出特性。     

SnO_2／p接触特性对a－Si太阳电池填充因子的影响

用ＰＥＣＶＤ方法制备出高电导率（～０．２ｓｃｍ－１）、宽带隙（～２．２ｅＶ）的Ｐ型微晶化硅碳合金（ｐ－μｃ－ＳｉＣ：Ｈ）薄膜材料。利用ｐ－μＣ－ＳｉＣ：Ｈ／ｐ－ａ－Ｓｉ：Ｈ复合结构做ａ－Ｓｉ太阳电池的窗口材料，明显改善了ＳｎＯ２／ｐ之间的接触特性，从而使１０ｃｍ×１０ｃｍ单结集成型电池的填充因子从０．７０以下提高到０．７２。     

生物质热解的灰色关联度分析与多元回归模型优化研究

影响生物质热解的因素很多,文章只考虑影响热解产物的5个重要因素:物料性质、填实度、热解终温、物料粒径和加热速率,使用灰色关联度分析计算得出影响热解产气率、气体热值、焦油产率、半焦产率等因素的关联度数值依次为热解终温>物料特性>加热速率>物料的填实度>物料粒径。采用3种回归方法拟合参考因素和影响因素之间的关系,经过回归显著性F—检验后得出逐步回归方法拟合效果“最优”,如半焦产率逐步回归方程最终检验结果F=139.23>F(5,23,0.95)=2.64,剩余标准差(RMSE)=0.02418,模型和实验吻合得很好,同时结合先进的计算软件可使工艺过程优化和简单化。     

废轮胎中试回转窑热解炭特性分析

采用中试回转窑热解装置对废轮胎进行了热解研究，在450—650℃热解试验温度范围内，热解炭产率约为39%—44%。热解炭的工业及元素分析显示，热解炭中灰分含量高达10％以上；含量最多的金属元素是Zn和Fe；热解炭S含量2．2%—2．6％左右，轮胎原料中S元素约75%留在热解炭中，因此热解过程中排放出的气体硫化物很少。此外，探讨了热解炭孔容积分布和温度对比表面积的影响，在450—550℃，热解炭比表面积随热解温度升高而增大；温度继续升高，比表面积变化不大，在孔半径约为25nm处，热解炭比孔容积有最大值。     

固体废弃物热解半焦特性的研究

文中对固体废弃物热解半焦的化学成分及反应活性进行了研究，物料本身的性质、热解终温等将直接影响半焦产率、半焦中的C、H、N、S元素的残余量及半焦CO2的反应活性。另外，混合物料的半焦产率及组成与各组分单质物料在相同条件下热解半焦产率按组分比例的代数和大致相等。     

城市生活垃圾热解焦对热解焦油的影响

为研究城市生活垃圾热解焦对城市生活垃圾热解焦油的影响,采用固定床对添加不同比例的城市生活垃圾热解焦的城市生活垃圾进行热解实验。实验结果表明:未添加热解焦时,城市生活垃圾热解焦油产率为38.38%;当热解焦添加比例为30%时,焦油产率为31.79%,焦油中的O/C由0.20下降到0.10,焦油热值由30.24 MJ/kg升高到35.81 MJ/kg;当热解焦添加量超过30%时,热解焦对热解焦油品质的改善作用减弱。利用GC-MS对热解焦油分析发现,热解焦添加比例为30%时,热解焦油中醇类和羧酸类分别下降了19.18%和13.73%,酯类和脂肪烃类分别增加了27.69%和5.63%。热解焦明显改善了热解焦油的品质,实现了一定程度的轻质化。     

催化剂粒径与质量对生物质热解焦油催化裂化反应的影响

针对催化裂化条件对生物质热解焦油处理的影响，以秸秆热解产生的焦油为原料，在固定床焦油催化裂化反应试验台上研究了催化剂作用下焦油催化裂化的过程，并对催化剂粒径和质量等参数对焦油转化效果和催化裂化产物的影响进行了分析．结果表明：减小催化剂的粒径或者增加催化剂质量能促进燃气中高热值大分子气体转化为低热值的小分子轻质气体，从而有效促进焦油裂化，提高燃气产率，降低燃气热值．     

块状废轮胎固定床热解特性实验研究

国内外对于废旧轮胎热解的研究大多集中在对轮胎小颗粒的探索上,对于破碎成本较低的大块状轮胎的热解较少有人涉及.为了探究块状轮胎的热解特性,文章在外热式固定床热解炉上进行了不同热解温度下块状废轮胎热解特性的实验研究.结果表明:块状废轮胎热解产生的燃气成分主要为CH4,H2以及大分子烃类CnHm,且其燃气产率随热解温度的升高而增加.当热解温度高于550℃时,热解产物CnHm有二次裂解现象,热解产生的燃气具有较高热值;热解温度为600℃时,燃气热值可以达到26 MJ/m3;随着热解温度的提高,热解炭中挥发分含量减少,固定碳含量略有增加,热解温度对热解油及热解气产率影响明显.与小颗粒轮胎相比,块状轮胎热解气中小分子气体CH4,H2等含量相对较少,而大分子烃类含量相对较多.热解产物产率方面,热解炭和热解气的产率更大,焦油产率降低.     

Study on solid waste pyrolysis coke catalyst for catalytic cracking of coal tar

Low value solid waste pyrolysis coke was used as a catalyst to catalytically crack gas-phase tar to improve tar yield and gas production. Pyrolysis coke with different pyrolysis final temperature and pyrolysis time were prepared, the effect of tar cracking products was studied, and the optimal pyrolysis coke were screened. The pyrolysis coke catalyst was characterized by BET, FTIR, SEM. The results show that the optimal preparation final temperature of pyrolysis coke is 750 °C, and the optimal preparation pyrolysis time is 2 h. Compared with the pyrolysis of raw coal, the tar cracking rate increased by 9.3%, after added the pyrolysis coke catalyst, the gas increased by 23.2%, and the light component increased to 36.6%. And the OH, C–N and C–O–C functional groups present on coke are the factors that affect the catalytic cracking.     

Modeling of beech wood pellet pyrolysis under concentrated solar radiation

A two-dimensional, unsteady CFD (Computational Fluid Dynamics) single particle model was developed and used to simulate the solar pyrolysis process of beech wood pellets (10 mm in diameter and 5 mm in height). Pseudo-stoichiometric coefficients about the mass fraction of primary tar converted by the reaction into gas and secondary tar were determined at different temperatures and heating rates for the first time. The 2D model predictions were successfully validated with tests performed at 600 °C to 2000 °C final temperature, with 10 and 50 °C/s heating rates. The evolution of the final products and mass losses of pyrolyzed biomass are enhanced with temperature and heating rate. Moreover, the higher the temperature and heating rate, the higher the gas yield. This emphasizes the intra-particle tar secondary reaction into gas for pyrolysis of large size sample under high temperature and heating rate.     

温度对生物质热解产物有机结构的影响

在管式炉上研究了生物质在不同温度下的热解过程,采用傅立叶红外光谱仪研究了热解温度对稻草热解固体产物半焦和液体产物焦油的有机结构变化的影响,用色质联用仪(GC/MS)分析了焦油的主要成分随温度的变化。研究表明,生物质的热解主要集中在200～600℃,高温有利于气体产物的析出,半焦的量及其所含的有机官能团(C=O,C=C,C-H,C-O和OH等)随热解温度的升高快速减少;焦油的量随温度的升高先增大后减小,在500℃时达到最大值,焦油中官能团的种类较稳定,但是吸收峰强度随温度的升高呈减弱的趋势。     

Influence of temperature on organic structure of biomass pyrolysis products

Biomass pyrolysis experiments were performed in a tubular reactor at different temperatures, the effects of which on organic structure of semi-char and tar had been investigated. Fourier-transform infrared (FTIR) analysis was conducted by a Nicolet 6700 FTIR spectrometer. The tar components at different temperatures were analyzed by GC/MS. It was observed that pyrolysis of biomass mainly occurs in the temperature range of 300–600 °C. A high temperature favored the production of gases. The yield of semi-char and the contained organic functional groups(CO, CC, C–H, C–O and OH) decreases significantly with the increasing final temperature. The tar yield passes through a maximum at about 500 °C. The organic functional groups in tar were stable but the transmittance of these groups decreased with the increasing final temperature.     

Provisional protocol for the sampling and anlaysis of tar and particulates in the gas from large-scale biomass gasifiers. Version 1998

This paper presents tar sampling protocols for pressurised and atmospheric large scale gasification processes. Methods for constructing sampling lines either to on-line analysers or into sampling systems are described. The tar sampling system consists of a heated probe, a particulate filter and a series of impinger bottles. Dichloromethane is used as the tar abosrbing solvent. The solvent containing bottles are placed in a cold bath so that gradual cooling of the sampled gas from about 0°C to the final temperature −79°C takes place in them. Recommendations for suitable sampling gas flow rates and gas temperatures are given. Tar characterisation methods based on different garvimetric measurements and GC analysis are described.     

Yields of pyrolysis products from refuse-derived fuel

Pyrolysis yields and gas characteristics must be studied to control pollution caused by waste-energy recycling and to develop a refuse-derived fuel technology. In this study, refuse-derived fuel pyrolysis experiments were performed in a high-temperature tube furnace. The effects of the final pyrolysis temperature, material mixture ratio, and pyrolysis rate on the yields of pyrolysis products, including gas, tar, and semi-coke, were studied. The volume fractions of the pyrolysis gas components (H₂, CO, CH₄, and CO₂) of the samples were also detected. Results showed that with increased final temperature, the tar and gas yields increased but the semi-coke yield decreased. The volume fractions of the components had the following trends: H₂ increased, CO initially decreased and then increased, CH₄ initially increased and then decreased, and CO₂ decreased. With decreased biomass, the tar yield decreased and then increased, whereas the semi-coke and gas yields increased and then decreased. Compared with slow pyrolysis, fast pyrolysis decreased the tar yield by 9.13%, increased the gas yield by 7.45%, increased the CO and CH₄ volume fractions, and decreased the CO₂ volume fraction.     

生物质气化过程中焦油的生成

总结了生物质气化过程中焦油的生成和分类,以及气化炉炉型、温度与氧量对焦油生成量和组成的影响规律。初级、二级和三级焦油是应用最为广泛的一种分类方法;不同炉型气化炉产气中焦油质量浓度从大到小依次为:上吸式流化床下吸式,分别在100,10,1g/m~3的量级,两段式等改进炉型在焦油控制上更有优势;上吸式气化炉焦油多为初级组分,下吸式则以无取代基的多环芳香烃等三级焦油为主,而流化床的焦油涵盖了二、三级焦油组分;温度的升高使得焦油量下降,且趋向于转化为化学结构更稳定的三级组分;氧量的增多对焦油的生成具有抑制作用。     

裂解温度对生物质热解焦油成分的影响

以锯末粉体为生物质热解焦油研究对象,研究了热解温度对焦油产量和焦油化学成分的影响规律,结果表明,热解温度为500℃时,生物质热解产生的焦油量最大,温度过高或过低都有利于焦油的减少。不同热解温度下,焦油中碳氢化合物的成分主要是芳香烃和少量的脂肪烃,含氧化合物主要是苯酚及其烷基衍生物,含氮化合物主要是吡啶、吡咯及其烷基衍生物等杂环化合物。     

Investigation on the thermal behavior characteristics and products composition of four pulverized coals: Its potential applications in coal cleaning

Although the thermochemical conversion of coal has dominated the research concerning the primary chemical production in the coal chemical industry utilization field, obtaining higher tar yield and lighter tar quality remain as challenges. The pyrolysis and its product distribution were studied using a thermogravimetric analyzer and a fixed bed reactor. A gas chromatograph (GC) and a gas chromatograph−mass spectrometer (GC-MS) were employed to test the properties and composition of the pyrolytic products. Here, we demonstrated that the tar yield only fluctuates when the carbon content is approximately 80%. The ratios of aliphatic hydrogen to all the functional groups (Ib₁) are the largest in HM2 coal, while the change of the ratios of aromatic hydrogen to all of the functional groups (Ib₂) is the same as that of the tar yield. With the increase of coalification, the ratio of CH₂ to CH₃ in the aliphatic structure (Ic₁) decreases. The oxygen containing functional groups in YL coal were mostly converted into tar products, but the corresponding functional groups in ZC3 coal decompose to form more water. When the final pyrolysis temperature is below 550 °C, there was a higher yield of gaseous products containing carbon and oxygen than of gaseous products containing hydrogen. With the decrease of the H/C ratio, the relative content of the aliphatic hydrocarbon and phenolic compounds in tar increased, while the benzene series and polycyclic aromatic hydrocarbons decreased.     

焦油对生物质气化再燃还原NO的影响

采用配制含焦油模型化合物的生物质气的方法,实验研究了焦油的加入对生物质气化再燃还原NO的影响.模拟的生物质气化气由H2、CH4、CO、CO2、N2构成,并选择了苯、甲苯、苯酚和苯乙烯作为焦油模型化合物.实验在电加热的刚玉管流反应器中进行,实验温度在900～1,400,℃之间.研究了反应器入口焦油含量、氧气浓度、NO初始浓度、反应停留时间及反应温度等因素对还原NO的影响,分析了含焦油的生物质气化再燃特性.证实了焦油有助于提高生物质气化气还原NO的效率;含焦油的生物质气化再燃的最佳当量比在1.20～1.65之间,并且随着NO初始浓度的增加及停留时间的延长,NO还原效率逐渐增加;高温下,焦油含量较高时,有炭黑生成.