烘焙预处理对玉米秸秆磷酸法活性炭制备及性能影响

以玉米秸秆为原料,研究烘焙预处理对磷酸法活性炭的制备及性能影响。研究结果表明：烘焙预处理使玉米秸秆碳元素含量和固定碳含量增加而挥发分含量降低,增加热解焦炭质量,且烘焙温度影响强于烘焙时间。烘焙处理使玉米秸秆活性炭比表面积先增加后减小,总孔容和中孔率减小,而微孔率显著增加。烘焙预处理有助于提高活性炭吸附性能,当100 g粒径为154～450μm玉米秸秆颗粒经烘焙预处理,预处理条件为烘焙温度240℃、烘焙时间60 min时,预处理后的玉米秸秆含C 51.32%,固定碳27.64%,灰分4.72%。采用磷酸活化法将预处理后的玉米秸秆制备成活性炭,制备条件为浸渍比1∶4(玉米秸秆与55%磷酸溶液的质量比),浸渍温度140℃,浸渍时间90 min,活化温度400℃,活化时间60 min,此条件下制备的玉米秸秆活性炭比表面积达1 317.05 m²/g,碘吸附值、亚甲基蓝吸附值和焦糖脱色率分别为876 mg/g、 210 mg/g和100%。     

钙基添加剂对不同煤种解耦燃烧下硫释放的影响

煤燃烧后排放的硫氧化物导致的环境污染问题已经引起人们的日益关注。基于一段式和两段式卧式炉,本文探究在传统燃烧和解耦燃烧条件下,温度、煤种以及CaO对燃煤释放SO₂规律的影响。试验结果表明：不同煤种的SO₂释放规律存在差异。随着温度的升高,不同煤种燃烧SO₂的释放量均不断增加,硫的动态析出曲线逐渐由单峰分布转化为双峰分布。传统燃烧模式下,添加的CaO对烟煤、无烟煤和褐煤脱硫效率可以达到70%以上,高氯煤脱硫效率则较低,仅有12.09%～20.45%;随温度升高,烟煤、褐煤和高氯煤的脱硫效率呈现先略微下降,后升高再下降的趋势,烟煤脱硫效率则逐渐降低。解耦燃烧模式下,CaO对烟煤、无烟煤脱硫效率在42.35%～76.23%,褐煤在21.35%～52.63%,高氯煤脱硫效率仍然较低,在8.93%～10.57%;随温度升高,烟煤、褐煤和高氯煤的脱硫效率呈现先增加后降低的趋势,烟煤脱硫效率逐渐降低。解耦燃烧模式下,不同煤种SO₂的总释放量大于传统燃烧模式,添加CaO后脱硫效率小于传统燃烧模式。     

给水管网水中氯胺消毒的氨氮释放规律

研究了对不同氯氨比条件下氯胺释放氨氮的规律,考察了pH、有机物浓度、亚硝酸盐浓度和Fe2＋对氯胺释放氨氮规律的影响。结果表明随着氯氨比的增加氨氮释放量降低,Cl∶N＝3∶1和Cl∶N＝5∶1的氯胺释放氨氮的量分别为0．91和0．35 mg/L;pH对氯胺释放氨氮有一定影响,氨氮浓度随着pH升高而降低;有机物含量和亚硝酸盐浓度对氯胺释放氨氮有显著影响,随着有机物和亚硝酸盐含量的增加,氯胺释放的氨氮浓度增加;管网中的 Fe2＋也会加快氯胺释放氨氮的速度。     

纳米CaO-Fe(Cp)2复合催化剂对烟煤燃烧性能的影响

在煤炭催化领域,无机铁系催化剂易中毒,CaO分散性较差,为了提高催化效率,急需寻求一种新型有机-无机复合燃煤催化剂。采用高温煅烧氧化钙,二氯化碳溶液浸渍的方法制备负载率为85.46%纳米氧化钙负载二茂铁复合催化剂(CaO-Fe(Cp)_2),并对华亭东华镇煤矿烟煤的烧失率、热值释放率、硫释放率、灰分、灰融性等催化性能进行研究。纳米CaO-Fe(Cp)_2复合催化剂在烟煤燃烧过程中的催化性能明显优于单独添加CaO和二茂铁的煤样。500℃燃烧2.5 h时,添加纳米CaO-Fe(Cp)_2复合催化剂煤样烧失率比原煤提高24.95%,比添加1%纳米CaO煤样增加13.20%,比添加1%二茂铁煤样增加6.95%。添加纳米CaO-Fe(Cp)_2复合催化剂煤样的热值释放率比原煤增加27.16%,比添加1%纳米CaO煤样增加9.63%,比添加1%二茂铁煤样增加4.75%。添加纳米CaO-Fe(Cp)_2复合催化剂煤样的硫释放率比原煤降低5.87%,比添加1%纳米CaO煤样增加3.98%,比添加1%二茂铁煤样降低9.92%。添加纳米CaO-Fe(Cp)_2复合催化剂煤样的灰分比原煤降低10.58%,比添加1%纳米CaO煤样降低13.50%,比添加1%二茂铁煤样增加4.28%。研究表明:纳米CaO-Fe(Cp)_2复合催化剂在煤炭中分布均匀,增大了与煤炭分子的接触面积,增加了反应活性,加快燃烧速率,促进硫释放,降低了灰分,在催化初期缓慢释放Fe_2O_3,避免催化剂中毒。二者协同催化作用,具有良好的催化助燃和节能环保作用,是一种新型高效燃煤催化剂。     

复合垃圾衍生燃料燃烧-热解特性的研究

采用热重和气-质联用仪对复合垃圾衍生燃料(CRDF)的燃烧特性和氯释放特性进行分析,结果表明在燃烧和热解条件下,CRDF中氯的释放特性有明显的区别,在温度为500～600℃时CRDF燃烧无机氯的释放率可达90%以上,而CRDF热解无机氯的释放为76%;当温度达800℃时CRDF热解过程释放的有机氯化合物种类和浓度均高于燃烧过程。热重分析结果显示CRDF在热处理中存在3个明显的失重阶段,第一失重阶段温度约200～300℃,失重率38.5%;第二失重阶段温度约为400～500℃,失重率为20.35%,第三阶段为一个缓慢的失重阶段,温度在600～800℃,失重率约22.35%。     

烘焙生物质燃烧过程中钾的赋存形态及析出迁移特性

选取稻秆和棉秆为原料,在烘焙预处理后,通过固定床燃烧实验结合HSC Chemistry热力学平衡计算,获得了烘焙生物质燃烧过程中碱金属K的析出和迁移规律。结果表明：烘焙过程中存在着少量水溶性K的释放及其向醋酸铵溶态K的转化,而其转化和释放能力与Cl/K呈正相关。烘焙生物质的成灰率随着燃烧温度的升高而下降,而K的释放率随温度的变化则相反,其主要释放形式为K的氯化物和KOH;此外,600℃时,水溶性K和醋酸铵溶态K主要转化为char-K,700~900℃时其主要转化为K的硅酸盐,随着温度的上升,其转化量不断增加。相比于原生生物质,烘焙生物质有更高的成灰率;此外,烘焙促进了生物质燃烧过程中醋酸铵溶态K向酸溶态或残渣态K转化,同时抑制了水溶性K的释放,这些使得烘焙生物质燃烧过程中K的释放率更低,而烘焙对生物质燃烧过程中K释放的抑制与烘焙过程中Cl的释放率呈正相关。     

洗选过程中硫元素迁移的影响与燃烧释放特性分析

分析煤炭洗选过程硫元素的迁移和燃烧释放特性。以产自山西的某煤炭作为原料,经过加热洗选获得煤炭产品后,分析洗选时间、洗选温度对于硫元素迁移影响,并对比洗选前后硫元素迁移特性。以未经洗选的原始煤炭、洗选后的精煤和矸石作为对象,分析温度、时间等因素对于硫元素燃烧释放特性影响。结果显示,随着洗选温度增加煤炭洗选后黄铁矿硫的脱出率最高,洗选温度升高降低煤炭含硫量,且对比来看,洗选之后硫元素出现降低迁移变化。燃烧释放试验显示,升高试验温度会导致硫释放量增加,高温环境反应20 min以后硫元素几乎完全释放。     

基于微波湿烘焙畜粪生物质提质研究

采用微波湿烘焙方法,对马粪进行烘焙预处理,考察了反应溶剂和烘焙温度对马粪组成、热降解特性、高位热值、能量产率及形貌特性的影响。结果表明,马粪的固定碳含量和高位热值随温度升高而增长,能量产率随温度升高而降低。与原料相比,在200℃时,水溶剂中所得烘焙马粪的固定碳含量大幅增长,O/C比减小28.00%,高位热值增长21.07%,能量产率保留74.30%。与原料相比,水和琥珀酸溶剂中所得烘焙马粪仍存在较多的灰分含量,硫酸溶剂能减少形成灰分的金属元素含量,使马粪灰分含量减少50.00%。微波湿烘焙降低了马粪的热解反应性,并提高其燃烧反应性。水溶剂中所得烘焙马粪,其表面的孔隙结构更清晰。研究显示,微波湿法烘焙可对马粪提质,200℃是本实验的最佳反应温度,恒温200℃时,水比稀酸更适合作为反应溶剂。     

生物质烘焙处理的能量平衡分析

基于烘焙过程分析,建立了生物质烘焙处理的能量平衡计算方法,结合固定床烘焙实验结果,研究了烘焙温度和保温时间对杨树枝烘焙特性、烘焙所需热及3种烘焙产物能量分布的影响,探讨了杨树枝烘焙处理的能量平衡. 结果表明,烘焙温度是影响生物炭得率、热值和能量分布的主要因素,随烘焙温度提高,杨树枝炭得率显著降低,液体产物和气体产物逐渐增加,杨树枝炭和不凝气体产物的热值显著增加,而液体产物热值变化不大. 烘焙产物中,杨树枝炭的能量显著高于液体和气体的能量. 随烘焙温度升高,杨树枝烘焙的能量平衡率先快速升高后趋于平稳,在温度225℃、保温时间30 min的条件下,烘焙可获得64.0%的杨树枝炭,能量平衡率约为2.5,烘焙所得液体和气体产物的燃烧热完全能满足杨树枝烘焙能量自给的需要.     

棉织物无甲醛抗皱整理中DMSO对BTCA交联性能的影响

1,2,3,4-丁烷四羧酸（BTCA）和棉纤维素的酯化交联反应活性因氢键作用而降低,因此在工业整理中存在烘焙温度过高的问题。研究了二甲基亚砜（DMSO）对BTCA整理工艺的影响,测试了织物中接枝和交联的BTCA含量以及其折皱回复角,同时借助傅利叶红外光谱对DMSO的作用机制进行研究。结果表明,当整理液中DMSO的含量为6%时,可以有效降低BTCA的烘焙温度,在160℃下烘焙3min后的棉织物折皱回复角为263.8°,其防皱效果优于经传统工艺（170℃下烘焙3min）整理后织物（259°）。DMSO因可以削弱BTCA与棉纤维交联体系中的氢键作用,不仅减弱了BTCA在纤维内部的聚集,有利于其扩散和成酐,还加剧了纤维素大分子链的热振动,从而有效提高了BTCA在棉纤维中的接枝率和交联率以及整理后织物的防皱性能。     

Release and transformation characteristics of chlorine,sulfur and AAEMs during cornstalk torrefaction

A fixed-bed tube furnace was used to study the release and migration and transformation of chlorine, sulfur, alkali and alkaline earth metals (AAEMs) in corn stalks at different baking temperatures. It was found that the release ratios of chlorine and sulfur, which increased continuously with temperature in the range of 220—300℃, were 10%—40% and 27%—60%, respectively. However, the absolute content of chlorine increased after torrefaction with the decreased ratio of alkali metal chloride and increased ratio of organochlorine (C—Cl). The absolute content of sulfur decreased significantly after torrefaction, meeting the sulfur requirement of commercial biomass pellets. In addition, the proportion of acid-soluble and insoluble Ca and Mg in hydrochloric acid also increased to a certain extent.     

The effect of coal sulfur on the behavior of alkali metals during co-firing biomass and coal

Biomass contains high amounts of volatile alkali metals and chlorine, which can cause deposition, corrosion and agglomeration during combustion. Meanwhile coal contains a certain amount of sulfur that produces serious environmental pollution following combustion. To investigate the effects of sulfur on the migration of alkali metals during biomass and coal co-combustion, thermodynamic equilibrium calculations were applied and experiments were performed in a laboratory scale reactor combining with a scanning electron microscope (SEM), X-ray powder diffraction (XRD) and other analytical approaches. The results indicate that inorganic sulfur FeS₂ addition significantly enhanced the formation of potassium sulfate when the S/K molar ratio was less than 2. Meanwhile increasing FeS₂ dosage reduced the formation of KCl(g) and KOH(g) and increased the release of HCl(g). In addition potassium sulfate can react with silica and aluminum to form potassium aluminosilicates and release HCl at the S/K molar ratio above 4.     

利用水泥窑处置垃圾焚烧飞灰过程中有害组分的挥发特性及模型研究

对掺垃圾焚烧飞灰配料进行煅烧,研究了有害组分(碱、氯、硫)的挥发特性,并建立了挥发及冷凝特征模型。试验结果表明:随飞灰掺量的增加和煅烧温度的升高,碱、氯、硫的挥发率提高;但不同飞灰掺量下,熟料对碱、氯、硫的固溶量相近;碱、氯、硫的开始挥发温度点及挥发率随温度上升而增大的规律各不相同;低率值配方(KH=0.90,n=2.0,P=1.1)的挥发率比高率值配方(KH=0.90,n=2.7,P=1.6)小。根据有害组分的挥发及冷凝特征模型,分析得到广州珠江水泥厂窑炉中由碱和氯引起的结皮主要发生在五级筒,由硫引起的结皮主要发生在上升烟道。     

微波烘焙预处理降解玉米秸秆

用微波可高效对生物质烘焙预处理,考察了不同微波烘焙过程对玉米秸秆主要组分的降解作用及酸、碱、甘油催化剂对纤维素转化效率的影响,并对预处理的玉米秸秆进行酶解实验。结果表明,单纯的微波预处理对玉米秸秆中主要组分纤维素、半纤维素和木质素均有强烈的转化作用。无催化剂微波烘焙后,样品中纤维素含量降低了30%。在微波烘焙中添加酸、碱、甘油催化剂,可选择性降解玉米秸秆中的半纤维素或木质素,有效提高预处理后玉米秸秆中的纤维素含量,添加NaOH后纤维素含量增加最明显,由33%增至42%,纤维素最高转化率达65%。     

Preparation of chlorosulfonated polyethylene by the gas‐solid method

Chlorosulfonated polyethylene (CSM) has been prepared by the gas‐solid method in a tank reactor using chlorinated polyethylene (CPE) and a gaseous mixture of chlorine and dioxide sulfur. Sulfur content of CSM determined by element analysis is used as a reference for the quantitative determination of the degree of chlorosulfonation. The effects of reaction temperature, effective gaseous mixture concentration, particle size of CPE, and the ratio of chlorine to dioxide sulfur on chlorosulfonation are investigated. The results indicate that with the increment of reaction temperature within the range of from 30 to 50°C, the rate of chlorosulfonation during the later reaction period (15–25 min) is markedly increased and the prepared CSM has higher sulfur content. It was also found that the rate of chlorosulfonation increases with the effective gaseous mixture concentration, and that the ratio of chlorine to dioxide sulfur is preferably 1 : 1. It was proven that HCl, by‐product of the chlorosulfonation, can accelerate the rate of chlorosulfonation when the volume concentration of HCl is lower than 40%, and that the presence of oxide results in higher sulfur content of the resultant CSM. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3582–3588, 2001     

Effects of chlorine and sulphur on particle formation in wood combustion performed in a laboratory scale reactor

Fine particle formation in wood combustion was studied in a laboratory scale laminar flow reactor at various flue gas chlorine and sulphur concentrations. Aerosol samples were quenched at around 850 °C using a porous tube diluter. Fine particle number concentrations, mass concentrations, size distributions and chemical compositions were measured. In addition, flue gas composition, including SO₂ and HCl, was monitored. Experimental results were interpreted by thermodynamic equilibrium calculations.Addition of HCl clearly raised fine particle mass concentration (PM1.0) which was because of increased release of ash-forming material to fine particles. Especially the release of K, Na, Zn and Cd to fine particles increased. These species form chlorides which apparently increases their volatilization from the fuel. When a sufficient amount of SO₂ was supplied in a chlorine rich combustion (S/Cl molar ratio from 4.7 to 7.5), most of the HCl stayed in the gas phase, release of ash-forming elements decreased and also fine particle concentrations dropped significantly. The sulphation of alkali metals is suggested to play a key role in the observed decrease in the fine particle concentration. It seems that the formation of sulphates leads to alkali metal retention in the coarse particle fraction.     

固定床无碱脱硫技术在液化气脱硫中的应用

由于原料油繁杂,厂里生产的民用液化气中有机硫含量较高。装置原采用醇胺溶剂脱除大部分H2S后再采用碱洗、水洗工艺,有机硫难脱除,液化气个别质量指标如铜片腐蚀不稳定,经常不合格;同时碱渣的处理也较困难。通过对原液化气脱硫工艺进行改进,采用液化气固定床无碱脱硫工艺及相关催化剂、脱硫剂,液化气中总硫含量由脱前的237.1mg/m^3降为脱后的104.4mg/m^3左右,主要是降低有机硫,总硫脱除率达到≥50%,液化气铜片腐蚀100%合格。