废轮胎中试回转窑热解气特性及能耗分析

在无氧气氛下用中试回转窑热解系统对废轮胎进行了热解试验,热解气用气相色谱仪进行分析,轮胎热解气体主要包含CO、CO2、CH4、C2H4、C2H6、C3H8、C4H8,以及它们派生的不饱和烃。热解温度的不同,回转窑微负压运行时,挥发分在窑内的停留时间不同,气体的成分有所变化。OH4在500℃达到最高,C2H4则在550℃产量最大,虽然温度的提高有利于大分子烃类二次裂解,但由于在窑内停留时间较短,产量反而在较高的热解温度65℃达到最大值,超过10％计算表明,热解气可以作为轮胎热解的热源。     

稻壳连续热解特性研究

在自行研制的生物质连续热解反应装置上进行稻壳连续热解和二次裂解实验研究。随着稻壳热解温度的提高,炭产率降低,气体产率增加,液体产率先增加后减少;随着滞留时间的减少,炭产率、液体产率增加,气体产率减少。稻壳热解气以CO2和CO为主,且二者为竞争关系,热解温度提高,CO2产量降低,CH4、H2、C2H4、C2H6产量增加,CO的产率变化不大;滞留时间对热解气组分影响不大。二次裂解温度提高,裂解气中的H2、CH4、C2H4含量明显增加,二次裂解温度为800℃时,H2产率达到12%。稻壳500℃热解挥发物600℃二次裂解木醋液中醋酸含量高达49.44%,焦油中检测到的物质主要为丙酮和异丙醇。     

微波热解工艺参数影响气液产物组成的研究

针对生物质微波热解生物油产率低且含水量高,气体产物较为复杂的特点,通过实验对热解参数、堆积程度、传热介质3个方面进行考察研究。实验结果表明,在热解温度为600℃,预热温度为160℃,填充程度为100%的条件下得生物油最大产率为51.12%,生物炭产率为26.56%,合成气产率为22.32%;生物油以酚类化合物和呋喃类化合物为主,合成气以CO,H2,CH4,CO2,C2～C4小分子气体为主。     

生物质快速热解气相成分析出规律

利用恒温沉降炉对秸秆、稻壳、木屑及一种烟煤煤粉在900、1000、1100℃ 3个温度进行了快速热解试验,对4种燃料在快速热解过程中气相成分析出的规律进行了研究.生物质成分中高的挥发分、氧、H/C决定了其快速热解会取得比煤粉高的气相产率,木屑的气相产物产量最多,秸秆次之,稻壳最低.4种燃料热解气相产物中的主要成分是CO、H_2、CO_2、CH_4,少量的G_2H_4、C_2H_6、NO、HCN、COS,生物质和煤粉在快速热解及短的停留时间内,其析出的氮前驱物为HCN.快速热解析出的气相成分产量及组分分布与燃料种类、热解温度、热解停留时间相关.几种物料共同的规律是随停留时间的延长,气相产物的量不断地增加,当气相产物的产量趋于平稳时,相应的气相产物的各组分趋于恒定,这一停留时间标志着热解过程的结束,相同温度条件下煤粉的热解速率要慢于3种生物质.     

固定床内生物质与废油脂共热解实验研究

在固定床反应器中,研究玉米芯单独热解与玉米芯/废油脂共热解反应,比较二者三相产物的异同。与单独热解相比,共热解工况下液体产物产率相对较高,气体及固体产物产率相对较低;共热解工况下液体产物含氧量更低,热值更高。二者液体产物的GC-MS及GC-FID分析结果表明:共热解含氧有机物(如苯酚、呋喃、乙酸等)低于单独热解,而烃类有机物(如甲苯、二甲苯等)高于单独热解;气体产物分析表明:共热解CH4、C2H4、C2H6、C3H6、C3H8的浓度均高于单独热解,CO浓度变化不大,CO2浓度相对减少。液相与气相产物品质的提高主要是由于废油脂的添加可增加热解原料的有效氢碳比,这为利用废油脂提供了新的思路。     

污泥-花生壳共热解气相产物研究

采用外热式反应釜,以CH_3COOK为催化剂进行污泥-花生壳共热解气相产物的研究。考察花生壳添加量、热解温度、催化剂添加量、热解时间对共热解气相产物的产率、组成和热值的影响。研究结果表明:随着花生壳添加量的增加,气相产物的产率和热值均先增大后减小,花生壳添加量为80%时,气体热值达到最大,CH_4体积百分数达到10.57%;随着热解温度的升高,气相产物的产率和热值均先增大后减小,H_2体积百分数呈增大趋势,热解温度为600℃时,气体热值达到最大,CH_4体积百分数达到21.86%;随着催化剂添加量的增加,气相产物的产率和热值均先增大后减小,催化剂添加量为6%时气体热值达到最大;随着热解时间的延长,气相产率迅速增大后趋于平缓,气体热值缓慢增大后减小,热解时间为150 min时,气体热值达到最大值27.92MJ/m3,CH_4体积百分数达到28.33%。     

污水污泥在流化床中快速热解制油

采用流化床污泥热解制油系统,在300～600℃进行污泥快速热解试验,研究了污泥在不同热解温度下的热解特性.结果表明,随着反应温度的提高,残炭的产率减少,不凝结气体产率增加,热解油产率在300～500℃以下随着反应温度的升高逐渐增加,在500℃时达到最大值46.31%,随后逐渐减少;不凝结气体主要由CO_2、CO、H_2、CH_4、C2H_4、C2H_6、C_3H_6和C_3H_8等组成,各成分随反应温度的升高呈规律性变化;通过GC-MS联用分析技术,对热解油中的29种含量(峰面积百分比)大于1%的成分进行了定性分析,400℃时热解油中酯类的含量(峰面积百分比)占绝对优势,而在600℃时,烯烃的含量(峰面积百分比)最多,各种组分的分布较400℃时均匀.     

玉米秸和稻壳热解产物的分布规律

研究了玉米秸和稻壳热解产物在不同反应温度和停留时间下的分布规律.试验结果表明,400℃时热解产物中液体质量分数接近50%;随着反应温度升高,大分子的碳氢化合物逐步裂解,气态产物逐渐增多,800℃时气体产物质量分数超过了55%.反应温度对热解产物的分布具有显著影响,而停留时间影响较小.随着反应温度升高,H2含量明显增加,CO和CO2含量明显降低,CH4含量受温度的影响较小.当反应温度在400～500℃时,热解气体的低位热值在11～15 MJ/m3;反应温度超过500℃时,气体热值在15～16.5 MJ/m3.     

谷壳热解/气化的热重-红外联用分析

利用热重分析(TGA)和傅里叶红外光谱(FTIR)联用技术对典型生物质热解和气化特性及其气体产物的释放规律进行了研究,并确定了其热解和气化机理.研究表明,谷壳在N2和GO2气氛下的热解失重主要集中在220～600℃,并且具有相似的热解特性;在800℃以后谷壳在N2和CO2气氛下反应所对应的热重曲线出现了较大的差异.气体产物主要在240～600℃析出,主要成分为H2O、CO、CH4、CxHy(x>1)和一些有机碳水化合物,其中H2O的析出温度较低,而CH4和CO析出温度相对较高;由于谷壳气化过程中存在CH4和CO2重整反应,使得H2O析出呈现双峰形式,并且CH4,含量相对于热解时偏小,CH4的析出特性曲线仅有一个峰,CO的析出特性曲线是双峰形式,且CO的释放曲线和谷壳反应速率曲线有着相似的特征温度和变化趋势.谷壳的热解服从两步反应机理,低温段的热解机理函数为f(α)=(1-α)2/3,高温段的热解机理函数为f(α)=(1-α)2.5;而气化机理函数为f(α)=(1α)2/3.     

生物质在高温下的动态热解及元素析出特性

利用管式炉在800~1 200℃的温度下对麦草、稻草和元宝煤进行高温热解,并通过红外光谱分析仪和氢气分析仪对析出气体的成分进行测量,研究结果表明:麦草和稻草的NH_3,HCN,H_2和主要烷烃气体的析出曲线均呈现为单峰状,其中,H_2最晚析出且析出时间最长;随着热解温度的升高,麦草和稻草的NH_3,CH_4和C_2H_4析出量均逐渐减小,H_2析出量逐渐增大且增速快于元宝煤,当热解温度约为1 100℃时,麦草和稻草的HCN析出量均达到最大值;当热解温度约为1 010℃时,稻草的C_2H_2和C_6H_6析出量最大,而麦草的C_2H_2和C_6H_6最大析出量对应的热解温度分别约为1 030,1 060℃;麦草和稻草析出气体的碳元素质量分数均随着热解温度的升高而逐渐减小,氢元素质量分数在热解温度为1 000℃时最小,氮元素质量分数在热解温度为900℃时最大,麦草析出气体的氧元素质量分数随着热解温度的升高而逐渐增大,而稻草析出气体的氧元素质量分数在热解温度为1 000℃时最大。     

Characteristic and utilization of pyrolysis productions from Dianchi Lake’s sediment in Yunan province in China

In the process of pyrolysis of Dianchi Lake’s sediment, a large number of productions (including gas state, liquid state, and solid state) were obtained. This research analyzed the characteristics and utilization of the representative pyrolysis products by gas chromatography, gas chromatograph-mass spectrometer, Brunauer–Emmett–Teller measurements, and X-ray fluorescence methods. The main gas components were H₂, CO, CH₄, CO₂, C₂H₄, and C₂H₆ in pyrolysis productions of the Dianchi Lake’s sediment. The flammable gases, H₂, CO, and CH₄, were vastly generated at the high-temperature section (>800°C). The main liquid components of pyrolysis products were phenol and hydroxy derivatives, which have no fuel use value, but abundance of phenol and its derivatives can be used as chemical raw materials. Solid products were in the enrichment of Si, Al, Fe, and other mineral elements, which have a good application prospect as building materials.     

核桃壳热裂解产物有机结构演变规律

采用TG-FTIR、Py-GC/MS对核桃壳热裂解过程及产物进行研究,利用1H-NMR和13C-NMR对热解炭结构进行分析,探讨热裂解产物有机结构演变规律。结果表明:核桃壳热裂解分为干燥脱水,快速热裂解和残余物缓慢热裂解三个阶段,快速热裂解阶段是主反应阶段,失重可达总失重的89%。不同热解温度下的液态产物成分不同,且随着热裂解温度的升高,低温下形成的热解液会发生二次反应生成新的热解液成分,热解温度由400℃升至600℃,液态产物完成了由酚类、醇类、酸类向酯类、芳香类的转化。升温核桃壳热裂解过程中的气态产物为H_2O,CO_2,CH_4和CO,在357℃时达到最大产量。随着热解温度由300℃升高到800℃,核桃壳热解炭由以苯环、烷烃链、甲氧基、羟基、羰基为主要结构转化为90%以上的芳香结构。     

储运油泥热解机理研究

利用管式炉,通入氯气和二氧化碳两种不同气氛,研究储运油泥的热解特性.分析油泥的气、液、渣的不同特性,探讨两种气氛下的不同热解特点.二氧化碳气氛下油泥热解的最佳温度为450℃,而氮气气氛下为500℃2.二氧化碳气氛下的渣是致密性渣,氮气气氛下是薄壁型渣.冷凝液中的低烷烃类、单环芳烃,二氧化碳气氛下比氮气气氛下高.而气体成分中甲烷和氢气含量氮气气氛比二氧化碳下高.得出同温度下,氮气的热解程度大于二氧化碳,而且二氧化碳参与了热解反应.     

High-temperature pyrolysis behavior of two different rank coals in fixed-bed and drop tube furnace reactors

In order to explore the high-temperature pyrolysis behavior and mechanism, two different rank coals (Shenhua bituminous coal and Baiyinhua lignite coal) were pyrolyzed in fixed-bed and drop tube furnace (DTF) reactors. Pyrolysis gas production was online quantified by a drainage method while the gas composition was detected by the gas chromatography. The physical and chemical characteristics of pyrolysis char were observed by N₂ absorption and FTIR. Results show that pyrolysis gas release rate and total production increase with the higher temperature. The gas production of SH coal (618–749 ml/g) is always higher than that of BYH coal (418–510 ml/g) due to its higher volatile content. The main high-temperature pyrolysis gas products are H₂ (∼50% vol), CO, CH₄ and CO₂. Carbon-reduction reaction at high temperatures can further form H₂ and CO while the rupture of aromatic heterocyclic ring can generate CH₄. High-temperature pyrolysis can greatly remove the coal moisture, develop their pore structures, crack the chemical functional groups (O–H, –CH₃, CO, C–O, etc.) and upgrade the coal rank. Different coal structures and pyrolysis heating rates result in various gas evolution and char formation behaviors. Higher heating rate can help to quickly generate large amounts of free radicals and change the pyrolysis behaviors.     

实现CO2零排放的煤气化制甲醇创新工艺

粉煤气化制生产甲醇的合成气（CO＋H2）,其H2／CO（物质的量比）为0．42,而合成甲醇的H2／CO应为2。所推荐的创新工艺,通过配入水电解制的H2,使合成气巾的H2／CO达到2,从而免除了传统煤制甲醇工艺中把多余的CO同水蒸气转换成H2＋CO2,传统工艺不但浪费了资源,还造成CO2大量排放。有人曾实验用CO作水电解介质制氢,使1m^2的H2的耗电量从4．76kW·h降到1．667kW·h,所推荐的创新工艺可利用高CO含量的部分煤气作水电解介质循环制氢配入合成气中,使其H2/CO达到2,这样煤气中的CO还可增产1倍的甲醇。所用的壳牌粉煤纯氧气化工艺,通过改造使气化压力从4MPa提高到6～6．5MPa,就可实现等压合成甲醇,从而可省去合成气压缩机,简化工艺流程．节省能耗和投资。建议国家进行投资,在四川沪州地区开发建设煤气化配水电解制氢联合制合成气用于生产2×（60×10^4t／a）甲醇的示范装置,然后完善推广。     

Influence of FeCl3 and lime added to sludge on sludge–coal pyrolysis

Copyrolysis of sewage sludge–coal blends at different ratios (0:100, 10:90, 50:50 and 100:0) was investigated using a simultaneous thermogravimetry–mass spectrometry analyser. During copyrolysis three thermal decomposition stages were identified between 180 and 800 °C. From 180 °C to 385 °C, the process is dominated by the sludge pyrolysis. From 385 °C to 560 °C, the coal is pyrolysed with a lower fraction of the sludge. In the last stage, the coal pyrolysis occurs together with carbonate decomposition. In the operational conditions, copyrolysis occurs with some interactions, which are principally due to the fact that inorganic matter from sludge (mainly lime and FeCl₃) affects some secondary reactions. The composition of pyrolysis gas (H₂, CO₂, H₂O, light hydrocarbons, CH₃COOH, chlorinated hydrocarbons and HCl) depends on both the temperature and the influence of inorganic products added to sludge in the wastewater treatment plant. The addition of FeCl₃ with lime affects the process in two ways: 1) an increase of H₂ is produced at 488 °C due to lime action on water–gas shift reaction, and 2) an increase of HCl and chlorinated hydrocarbons at 470 °C is also produced. The kinetic parameters were determined by using the global reaction model for each one of two first consecutive reaction stages.     

Volatile gas release characteristics of three typical Chinese coals under various pyrolysis conditions

In order to reveal the volatile gas release characteristics under various conditions (pyrolysis temperature, particle size, coal rank and pyrolysis time), three different rank coals (Shenhua 2# bituminous coal, Baorixile coal, and Zhaotong lignite coal) were pyrolyzed in a tubular furnace and the pyrolysis gas was analyzed by online balance and gas chromatography. Results suggest that increasing pyrolysis temperature causes increased release volume of volatile compounds and higher calorific value due to substantial increase of H₂, an incremental increase of CH₄ and the changes in molecule ingredients of C₂C₄ structures. Meanwhile, larger particle size can significantly reduce the released volume for its longer diffusion distance and lower specific surface area. Compared with bituminite, lignite yielded more valuable pyrolysis gases and lower primary reaction temperature. The ideal pyrolysis temperature is 700–800 °C for low rank lignite and 800–900 °C for bituminites. Basically, the productions of CO and CO₂ are associated with oxygen element content in coal while CO₂ releases early mainly by the decarboxylation reaction. Based on the results in the whole pyrolysis process, the CH₄ of higher rank coals is mostly produced by the rupture of aliphatic side chain while the main CH₄ source in lignite is the rupture of alkyl side chains in aromatics.     

玉米秸秆催化热解试验研究

利用自行设计的固定床快速热裂解试验系统,研究了玉米秸秆催化热解(催化剂为CaO)规律及催化剂对热裂解产物分布的影响,探讨了CaO的催化机理.结果表明,750℃时,CaO在促进焦油裂解的同时,也促进了焦炭和气体产物的生成;CaO对气体产物中的CO2具有吸附作用,降低了CO2的含量,它对大分子脱氢具有明显的催化选择性,增加了产气中H2的含量.在试验中采用了2种催化剂添加方式,添加比为1:1(质量比);分析了不同催化剂添加方式对催化热解的影响;采用悬挂方式时产气率达到57.68%;采用混合方式时,燃气中H2含量高达33.33%,燃气热值达到了12.389 MJ/m3.