研制KOH/白云石复合催化剂,以松木屑为原料,在固定床气化炉中进行水蒸气气化实验,考察催化剂制备条件、反应温度、水蒸气流量、催化剂用量对气化合成气气体组分、产气率、产氢率及碳转化率等气化特性评价指标的影响,并对所研制的K/Ca复合催化剂进行SEM、XRD和孔隙结构分析.研究表明:K元素很好地负载在白云石上.由KOH质量分数6％、K/Ca物质的量比2:1和煅烧温度900℃制备的K/Ca复合催化剂的催化性能最好.气化温度从600℃增加到750℃,H2体积分数由40.70％增加至59.09％,产氢率由16.38 g/kg增加至90.64 g/kg,但继续升高温度会造成催化剂活性下降使得H2体积分数和产氢率均有所下降.水蒸气流量由0.4 mL/min增加至1.0 mL/min时,H2体积分数由52.75％增加至59.09％,产氢率由68.14 g/kg增加至90.64 g/kg,进一步增加水蒸气流量则会造成系统热量损失,使得H2体积分数和产氢率均有不同程度的下降.催化剂与松木屑质量比值为0.3 g/g时,H2的体积分数为59.09％,产氢率为90.64 g/kg;当质量比值增加到0.6 g/g时,H2的体积分数降低至58.50％,产氢率提高到103.18 g/kg,继续增加质量比,二者变化趋势明显缓慢,即催化反应基本达到平衡.综合考虑各方面影响,K/Ca复合催化剂催化松木屑水蒸气气化的最佳条件为反应温度750℃、水蒸气流量为1.0 mL/min,催化剂与原料质量比值为0.6 g/g,此时产物气中H2体积分数为58.50％,产氢率为103.18 g/kg,低位热值为10.94 MJ/m3,碳转化率为83.25％.

以竹屑为原料,使用氧气-水蒸气作为混合气化剂,在固定床气化反应器中进行竹屑的氧气-水蒸气气化实验,考察了气化温度、水蒸气流量和氧气用量比对竹屑气化制备富氢燃气的影响.研究结果表明:气化温度和水蒸气流量均对竹屑燃气中氢气体积分数影响较大,氢气体积分数随着气化温度的升高呈稳步增长趋势,随水蒸气流量增加呈先增加后减少趋势,分别在气化温度900℃和水蒸气流量0.7 mL/min时达到最大值;而随着氧气用量比的增加,氢气体积分数变化不明显.竹屑氧气-水蒸气气化制备富氢燃气最佳的气化条件为气化温度900℃、水蒸气流量0.7 mL/min、氧气用量比0.30,此条件下气化制备的燃气中氢气体积分数32.04％,热值11.37 MJ/m3,产气率1.40 L/g,燃气中CH4体积分数8.82％,CO体积分数26.34％,CO2体积分数30.55％,C2Hm体积分数2.24％.

稻壳是稻谷加工的剩余物,稻壳炭是稻壳热解得到的副产物;稻壳炭中富含碳和二氧化硅,与水蒸气反应可以得到富氢气体,同时得到富含二氧化硅的稻壳灰副产物,具有与硅灰相媲美的高硅火山灰活性,可以作为高性能的无机材料、建筑材料、吸附材料及催化剂载体等高附加值的产品加以利用.为获得富氢气体及富硅材料,以热解副产物稻壳炭为原料,在固定床反应器中以水蒸气为气化剂气化制备富氢气体,探究稻壳炭的气化反应特性及气化产物分布与温度的关系,调控不同温度条件下的稻壳炭气化反应,通过生成气的组分分析及灰分生成率研究了气化温度对富氢气体产率、组分分布的影响;研究了稻壳炭气化固体剩余物稻壳灰的特性,对其进行SEM、XRD等表征,分析了其主要成分、表面结构等,研究反应温度对稻壳灰材料结构的影响.研究结果表明,反应温度的增加使气化产气率、产氢率及炭转化率均增加,950℃为最佳产气反应温度,产气率为2.1 L/g生物质,产氢率达到107.91 g/kg生物质,炭转化率为81.83％;气化固体剩余物稻壳灰的结构性质的变化趋势,则是反应温度越高,剩余物稻壳灰的灰分含量越高,SiO2含量也越高,但其片层结构破坏程度越严重,同时其中更多的无定形SiO2形成结晶,850℃以上则Si02更容易以晶体形式存在.

生物质气化制取富氢合成气因其原料的清洁可再生性、产物应用方式的多样性被认为是最具发展前景的制氢方式之一.催化剂对调控生物质气化产物组成及焦油的裂解具有重要作用.本文综述了化石能源制氢、水分解制氢和生物质制氢方法,分析了生物质气化制氢的优势和局限性,以及存在的问题;重点介绍了生物质气化制氢的影响因素(气化剂、反应温度和催化剂)和用于生物质气化的主要催化剂种类(镍基、白云石和碱及碱土金属催化剂)及其特点,分析国内外生物质气化制取富氢合成气和催化剂的研究现状,探讨了催化气化制取富氢合成气的发展前景,提出有待解决的问题和研究方向.

以杉木屑为原料,三聚氰胺固体废弃物(OAT)为氮源,基于碱/尿素体系溶解纤维素,通过一步热解制备氮掺杂活性炭,并考察活化温度和OAT加入量对活性炭的吸附性能和电化学性能的影响.通过X射线光电子能谱(XPS)和比表面积分析仪分析材料的表面结构和孔结构;采用循环伏安(CV)、恒流充放电(GCD)和交流阻抗(EIS)等测试手段表征其电化学性能.研究结果表明:随着OAT质量分数的增加,活性炭样品得率和吸附性能先增加后减小;OAT的添加有利于提高氮掺杂活性炭的得率、氮含量、吸附性能和电化学性能;炭材料的比表面积及其孔隙结构促进活性炭样品电化学性能的提升.当活化温度900℃,OAT质量分数为15％下,制备的氮掺杂活性炭的得率为34.2％,碘吸附值为1116 mg/g,亚甲基蓝吸附值为165 mg/g,比表面积为1324 m2/g,含氮量3.5％.在6 mol/L KOH电解液中,当电流密度1 A/g时,比电容可达193 F/g.

为满足汽车国六排放标准,以木屑为原料、磷酸为活化剂,制备了碳罐用高丁烷工作容量成型活性炭.在制备过程中通过烘焙提质、粒度调控对原料进行预处理,并采用了真空捏合、模孔设计、高温活化等工艺.考察了烘焙温度、原料粒度、浸渍比、真空捏合时间、活化温度、活化时间等制备条件对活性炭性能的影响.结果 表明:原料经250℃烘焙、破碎至粒度小于0.2 mm及使用孔径为2.5 mm的模具成型,可明显提高制备活性炭的性能;当磷酸与原料浸渍比为1.5∶1,真空捏合为60 min、活化温度为500℃、活化时间为120 min时,制备的活性炭碘吸附值为1028 mg·g-1、亚甲基蓝吸附值为270 mg·g-1、强度为92.4％、丁烷工作容量为152 g·L-1、BET比表面积为1547.63 m2·g-1,性能可达到碳罐用活性炭TGZ1500指标要求.

以木屑炭为原料,K2CO3作为催化剂,以固定床气化炉为实验设备,进行水蒸气催化气化木屑炭的探究.考察木屑炭水蒸气气化的炭转化率、产氢率、气体组成体积分数和H2/CO比值随K2CO3催化剂质量分数(0～8％)、水蒸气流量(0.15～0.35 g/(min·g》)、气化温度(800～950℃)变化的规律.实验结果表明:K2CO3催化剂可显著提升碳转化率及产氢率,K2CO3质量分数为8％时,碳转化率和产氢率分别达到86.3％和125.6 g/kg,同时合成气中CO体积分数显著增加,H2/CO比值降至2.43.增加水蒸气流量,合成气中H2含量显著增大,H2/CO比值随之增大.温度可有效促进炭气化过程,950℃时碳转化率和产氢率分别达到84.3％和127.1 g/kg,但合成气中CO体积分数增大,H2/CO比值降至2.48.实验得到H2/CO比值在2.43～5.16范围的合成气.气化反应温度在900℃、水蒸气0.2 g/(min·g)、K2CO3质量分数3％时,碳转化率可达80.4％,产氢率109.6g/kg,合成气中(H2+CO)体积分数82.4％,同时H2/CO比值高达3.05.

Charcoal catalytic steam gasification for syngas was investigated using a lab-scale fixed bed gasifier to study the effects of different catalysts, temperature, and steam flow rate. Four alkali salts of KOH, K2 CO3, KHCO3 and KNO3 were selected to pretreat charcoal. This paper discusses production of syngas from steam catalytic gasification of charcoal in a lab-scale ?xed bed reactor, using KOH, K2 CO3, KHCO3 and KNO3 as catalysts. The effects of different catalysts, steam flow rate and gasification temperatures on carbon conversion rate, hydrogen production rate, volume fraction of gas composition and H2/CO value of charcoal vaporization were investigated. The method of char absorbing catalyst was used to load catalyst in this work. The experiment used the absorption of potassium salt solution by carbon to load catalysts. The experimental results show that the four kinds of potassium salts can all improve the gasification efficiency of charcoal. With the same mass fraction of potassium salt solution, the catalytic activity of the four catalysts is in the order: KOH> K2 CO3> KHCO3> KNO3. In addition, the rate of carbon conversion and hydrogen yield production increased with increasing concentration of the catalyst concentration, but the increasing trend slows down gradually. With further increase the trend of high concentration increased gradually, so the mass fraction of catalyst solution was more appropriate in the 4％-6％ range. The H2 composition and the H2/CO ratio enhances with the increases of steam flow rate. The rise of temperature can promote carbon gasification reaction and the carbon conversion and hydrogen yield can reach 98.7％ and 145.23 g/kg at 950℃. The syngas of H2/CO ratio in the range of 1.53-4.09 was obtained. A promising application for biomass is liquid fuel synthesis, such as methanol or dimethyl ether (DME).

天然气因其清洁、高效、使用方便的特点而有着其他化石能源无法比拟的优势。随着天然气需求量的增加,天然气供需矛盾也逐渐凸显,生物质合成气催化制取合成天然气成为解决天然气供需矛盾的技术之一。针对生物质合成气甲烷化过程中存在的问题,从反应过程、催化剂、反应器等方面阐述了生物质合成气甲烷化研究现状;对比了不同催化剂的催化性能,分析得出Ni基催化剂是最适合工业化的甲烷化催化剂之一。列举了国外一些固定床和流化床甲烷化反应器工业化的案例,分析了其各自的生产工艺及优缺点,得出流化床是甲烷化反应器中较为有前景的反应器,并对生物质合成气催化制取合成天然气技术的发展方向进行了展望。

Steam gasification of bio-char had been studied in an updraft fixed bed reactor for hydrogen-rich syngas. The effect of different feedstocks,particle sizes and catalysts on steam gasification was investigated. The results showed that there were big diversity between different char gasifications. The results of wood chip char gasification were the best,followed by the corn cob char and rice husk char;and the worst results were strew char gasification. The maximum hydrogen yield of wood chip char was 222.8g/kg char. Particle sizes mainly affected the char conversion rate,which increased with the increase of particle size. The method of char adsorbing catalysts was efficient,and the catalytic ability of KOH was better than K2CO3at the same potassium salts mass fraction. The gasification rate with catalyst were twice of that without catalyst. Moreover,the char conversion rate increased with the rising of alkali concentrations,but higher concentration was not favoable for the hydrogen yield due to the increase of ash content. The maximum hydrogen yield of corn cob char gasification was 197.8g/kg char with alkali concentration of 6%.

Corncob char catalytic steam gasification for hydrogen-rich syngas was investigated using a lab-scale fixed bed gasifier to study the effects of temperature, steam flow rate, catalyst type and loading. The method of char absorbing catalyst was used to load catalyst in this work. Four alkali salts of KOH, K2CO3, NaOH and Na2CO3 were selected to pretreat corncob char. Results showed that hydroxides exhibited higher catalytic behavior. Further investigation on the effect caused by varying KOH concentrations to gasification performance has been done, and the maximum hydrogen yield of 197.8 g/kg char was obtained with 6 wt% concentration of KOH solution. Temperature and steam flow rate both has a positive influence on char conversion. Rising temperature promoted the hydrogen yield, and maximum hydrogen yield was obtained at 900 degrees C. With the steam flow rate increased from 0.2 g/min to 0.4 g/min, hydrogen yield increased by 84%, but a slight increase was found when steam flow rate further increased to 0.8 g/min.

Biomass steam gasification is an efficient thermochemical process,and it can converts raw materials to hydrogen-rich syngas which can be applied widely.It has potential to substitute fossil fuels to produce hydrogen.Different biomasses greatly affect the gasification and hydrogen production capacity.The choice of feedstocks is crucial for gasification to produce hydrogen-rich syngas.In addition,the adjustment of operation parameters including reaction temperature,steam flow rate,catalyst and adsorbent can optimize the quality of syngas and enhance hydrogen concentration.In this paper,the effect of operation conditions on biomass steam gasification for hydrogen-rich syngas was reviewed.Meantime,the research status of bio-char gasification for hydrogen-rich syngas was discussed.High quality of hydrogen-rich syngas can be produced by char gasification,which is kinetically limitation,thus this process requires catalyst to improve char reaction rate.It was also introduced the catalytic mechanism of potassium salts.The prospect of hydrogen-rich syngas application was proposed,including high purity hydrogen for fuel cell and synthetic natural gas.

以黑松松针为原料,采用水蒸气蒸馏的方法提取挥发油.经气相色谱-质谱联用分析,共分离和鉴定出45种化学成分,主要为β-蒎烯(28.49％)、α-蒎烯(13.55％)、氧化石竹烯(7.79％)、双戊烯(4.30％)、1-石竹烯(3.77％)、莰烯(1.36％)、α-石竹烯(1.16％)、长叶烯(0.86％)等烯烃类物质,其次还有α-松油醇(3.40％)、叶醇(1.44％)、4-萜烯醇(0.49％)等醇类物质,另外还检测出一些芳香烃化合物,如醛、酮、酚以及酸类物质等.

以木屑炭为原料,在上吸式固定床气化炉中进行水蒸气气化制备合成气,考察了温度和水蒸气流量对木屑炭水蒸气气化的产物分布、炭转化率、产气率、组成含量和H2/CO值的影响.结果表明:升高温度有助于木屑炭气化,炭转化率和产气率分别在950℃下达到最大值99.2％和4.16 L/g,但温度升高会导致H2从65.8％降至61.2％,同时H2/CO也呈下降趋势,从10.3降至3.35;水蒸气流量的增加可提升H2,从59.8％升至62％,但流量升至0.6 g/min时气化结果趋于稳定.水蒸气气化的最佳操作条件为900℃,水蒸气流量0.6 g/min,此条件下炭转化率、产气率和热值分别达到93.3％、4.06 L/g和9.04 MJ/m3,H2/CO值为4.11,适合于合成甲烷.

This work aims on the production of high quality syngas suitable for widely applications from catalytic woodchip char gasification in a lab-scale fixed bed reactor. Using the absorption of the char to load catalysts was conducted in this study. The results showed that the char conversion and hydrogen yield were increased significantly after impregnation with potassium salts. The catalytic activity of the four catalysts is in the order: K2CO3 approximate to KOH > CH3COOK > KCI. In addition, when 6 wt% of KOH solution was used to impregnate, the maximum hydrogen yield of 197.2 g/kg char can be obtained, but further increasing the mass fraction of impregnation solution had an adverse impact on hydrogen yield and H-2/CO. Moreover, the influence of particle size, reaction temperature and gasifying agent were investigated. The particle size of the char had little effect on gasification characteristics. Increasing temperature and steam amount were beneficial to improve char conversion and hydrogen yield, and the high quality syngas (H-2 + CO) with the ratio of 91.8% was obtained at 950 degrees C while the ratio of H-2/CO decreased from 3.7 to 1.65 with increasing temperature. Additionally, continuously increasing steam had little influence on gasification consequences and was poor in economy. Introducing oxygen can improve the char conversion and adjusted the ratio of H-2/CO in an economical way, but higher ER would weaken the quality of syngas.

The steam gasification experiments of sawdust for production of hydrogen-rich gas were carried out in the high-temperature fixed bed reactor using steam as gasification agent and CaO as catalyst.The effects of the molar ratio of CaO and carbon element of sawdust (n(Ca)/n(C)), temperature and steam flow rate on gasification characteristics were investigated.The results showed that with the increament of n(Ca)/n(C) from 0 to 1.0, the volume fraction of hydrogen increased from 45.58% to 58.62%, and the dry gas yield increased from 1.04 m3/kg to 1.38 m3/kg;the hydrogen content and dry gas yield only showed a modest increase as the n(Ca)/n(C) increased to 1.5. With increasing the gasification temperature from 700 to 750 ℃, the volume fraction of hydrogen significantly increased from 51.78% to 58.62%, and that of carbon dioxide decreased from 19.89% to 12.60%;as the temperature kept rising, the hydrogen content and the low heating value decreased.By increasing the steam flow rate from 0.1 g/(min·g) to 0.34 g/(min·g), the volume fraction of hydrogen increased from 58.62% to 62.55%.However, the hydrogen content, the hydrogen yield and the low heating value decreased when the steam flow rate was higher than 0.34 g/(min·g).The optimized conditions with CaO as catalyst were n(Ca)/n(C)=1, the gasification temperature 750 ℃ and the steam flow rate 0.34 g/(min·g).Under these conditions, the volume fraction of hydrogen was 62.55%, the hydrogen yield was 85.08 g/kg, the low heating value was 11.41 MJ/m3.

在高温固定床反应器中,以木屑炭为原料,进行木屑炭CO2气化的特性研究.考察了气化温度和CO2流量对燃气各组分体积分数、热值、固体产率、产气率的影响.结果表明:随着气化温度从750℃升高到950℃,CO体积分数明显增加,CO2体积分数明显减少,燃气热值增加较明显,而从950℃升高到1 050℃时,燃气热值增加趋势减缓.CO2作为气化介质,随着其流量增加,固体产率减少,气体产率增加,燃气组分中CO2体积分数明显增加,CO体积分数先增加后减少,燃气热值先增大后减小.CO2流量为15 mL/(min·g)时,燃气热值最大.气化温度950℃、CO2流量15 mL/(min·g)为较佳的气化条件,此时气化制备的气体中CO体积分数为51.51％,CO2体积分数为37.99％,燃气热值为8.03 MJ/m3,产气率为0.78 L/g.

Steam gasification of sawdust char for the production of hydrogen-rich gas was studied in a high-temperature fixed bed reactor.Experiments were carried out at 700-900 ℃ with steam flow rate of 0.11-0.32 g/(rmin·g) (based on the char,the same below).The effects of temperature and steam flow rate on the volume fraction of H2,gas yield,heat value and compositions were studied.The results showed that the excess steam led to a decrement of the gas heat value.Under the reaction conditions of temperature 900 ℃ and the steam flow rate was 0.32 g/(min·g),the volume fraction of H2 reached the maximum(62.53％),the heating value of the fuel gas was 8.99 MJ/Nm3 and the gas yield was 2.75 L/g.And the homogeneous volumetric model and shrinking core model were employed to obtain the corresponding kinetic parameters.The shrinking core model fitted the experimental data better than the homogeneous volumetric model.The acitivity energy and the pre-expenential factor obtained with homogeneous volumetric model were 88.67 kJ/(mol·K) and 2 976.55 min-1.The activity energy of the shrinking core model was 91.78 kJ/(mol·K) and the corresponding pre-exponential factor was 2 872.82 min-1.

Steam catalytic gasification experiments of pine sawdust to produce hydrogen-rich gas were carried out in a high-temperature fixed bed reactor with Ni-CaO as the catalyst. The influence of catalyst dosage,gasification temperature and steam flow rate on hydrogen content were investigated. The results showed that by increasing the catalyst to sawdust ratio from 0 to 1.5(g/g),the hydrogen content was increased from 45.58% to 60.23%,and the hydrogen yield was increased from 38.80 g/kg to 93.75g/kg,whereas the hydrogen content and hydrogen yield only showed a modest increase when the ratio was changed into 2. Increasing the gasification temperature from 700℃ to 750℃ significantly increased the hydrogen content from 54.24% to 60.23%,and decreased the carbon dioxide content from 21.09% to 13.18%,but higher temperature gave rise to a decrease in the hydrogen content and the low heating value.When the best gasification temperature was taken as 750℃,and the catalyst to sawdust ratio and the steam flow rate were 1.5(g/g) and 0.34g/(min·g),the resulting hydrogen content,dry gas yield and low heating value were 60.23%,93.75g/kg,and 12.13MJ/m3,respectively.

Co-processing methanol and ethanol in bio-char steam gasification was investigated in a fixed-bed reactor. The effect of reaction temperature, steam flow rate and additives content on gas composition and H-2 yield were evaluated. The results showed that bio-char is an ideal material for H-2 production, and the maximum H-2 yield (233.3 g/kg bio-char) was obtained in the absence of additives at 950 degrees C, 0.5 g/min steam flow rate, meantime, producing hydrogen-rich gas with slight formation of methane. Methanol and ethanol blended with steam, and subsequently introduced in reactor have positive effect on H-2 yield. However, taking the economy and char conversion rate into consideration, 5 vol%-8 vol% may be suitable contents, and H-2 yield increased to 342 g/kg and 308.9 g/kg with 5 vol% of methanol and ethanol added in gasifying agent at 950 degrees C and 0.5 g/min steam flow rate. Furthermore, the proposed catalytic gasification of hydrogen-rich gas for high purity hydrogen and synthetic natural gas may be a promising way for using the produced gases. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.