碱性双氧水预处理玉米秸秆性质研究

使用碱性双氧水对玉米秸秆进行预处理,可以有效提高秸秆的酶解效果。实验表明,最优预处理参数为使用分别占秸秆质量16%的 H₂O₂和25.6% 的NaOH,于40℃下预处理秸秆24 h。对经不同预处理剂处理后的秸秆进行酶解,发现NaOH及碱性双氧水预处理秸秆的酶解还原糖产量为7.48 g/L和8.26 g/L,而经H₂O及H₂O₂预处理秸秆的还原糖产量仅为1.35 g/L和1.59 g/L。通过木质纤维素含量及SEM分析发现,氢氧化钠主要作用为溶解秸秆中的木质素及半纤维素,而双氧水的存在则会破坏秸秆表面结构。计算秸秆预处理前后质量损失发现,双氧水的存在不能显著提高秸秆预处理后的质量损失,但会氧化分解被氢氧化钠溶解的大分子物质,对此过程机理及产物还需进行深入的研究。     

稀酸预处理玉米秸秆条件优化的试验研究

采用稀硫酸对玉米秸秆进行预处理,采用DNS法测定玉米秸秆水解液中还原糖的含量,对水解温度、水解时间、稀硫酸质量分数、固液质量比4个因素进行单因素试验分析,再通过正交试验对预处理条件进行优化.试验结果表明,最佳预处理条件:水解温度为121℃,水解时间为1 h,稀硫酸质量分数为0.6%,固液质量比为10%.     

卧式酶解罐用于预处理玉米秸秆水解研究

利用卧式滚筒酶解罐、立式搅拌酶解罐和卧式搅拌酶解罐分别对预处理玉米秸秆(PCS)进行水解研究,分析了酶解过程中p H、密度、总固体(TS)含量、纤维素含量(TC)、不可溶性总固体含量(FIS)、葡萄糖含量和木糖含量的变化趋势。卧式滚筒酶解罐用于TS含量较高的PCS酶解时,反应物容易粘附在反应桶内壁,不利于酶解有效地进行,138 h水解产生的葡萄糖含量为8.6%,低于立式搅拌酶解罐120 h水解产生的葡萄糖含量11.4%。而卧式搅拌酶解罐用于TS含量(25%)较高的PCS酶解时,120 h水解产生的葡萄糖含量为7.43%,比相同TS含量的立式搅拌酶解罐中葡萄糖含量高出0.26%。研究表明,3种酶解罐中,卧式搅拌罐更适合用于PCS的酶解。采用卧式搅拌酶解与同步糖化发酵耦合过程,TS含量为25%条件下,发酵液中乙醇含量可达到3.58%,纤维素水解率为76.8%。     

碱性胍预处理水稻秸秆研究

以水稻秸秆为研究对象,采用有机强碱——胍进行预处理,考察了催化剂用量、预处理时间和温度对预处理效果的影响。以扫描电镜(SEM)、X-射线衍射仪(XRD)、红外光谱仪(FTIR)、热重分析仪(TG)对预处理前后样品进行了表征。结果表明:胍用量为3%、温度为60℃、时间为6 h是较适宜的预处理条件,催化剂用量是预处理水稻秸秆最关键的因素。SEM照片显示,预处理后秸秆表面呈现不规则的层片状皱褶、裂缝和孔洞;XRD表征显示,预处理后纤维素结晶度均提高;FTIR表征显示,胍对去除木质素和降解氢键作用明显;TG表征表明预处理前后水稻秸秆具有不同的热稳定特性。     

稀硫酸预处理玉米秸秆条件的优化研究

对稀硫酸预处理玉米秸秆优化工艺条件进行了试验研究,在考察温度、时间、稀硫酸质量分数、固液质量比和玉米秸秆粒度5个单因素对预处理效果影响的基础上,采用响应面分析法对预处理条件进行优化,建立了以戊糖得率为响应值的二次回归方程模型,得到最佳预处理条件为水解温度120℃,水解时间75 min,稀硫酸质量分数1.0%,固液质量比1∶15,玉米秸秆颗粒为40目。此条件下,理论预测戊糖得率为65.018%,试验验证戊糖得率为64.37%,与预测值接近,说明预测模型可靠性较高,可应用于稀酸预处理条件的优化。     

玉米秸秆预处理对厌氧发酵制氢影响的研究

为提高玉米秸秆的产氢能力,实验研究了蒸汽爆破预处理、硫酸预处理、氢氧化钠预处理、盐酸预处理和酸化(碱化)气爆预处理5种预处理方法对玉米秸秆发酵产氢能力的影响。结果表明,预处理可以将秸秆中相当一部分纤维素和半纤维素水解生成还原糖,其中质量分数为0.8%的H2SO4酸化汽爆预处理对秸秆的水解效果最好。在固-液比1∶10、H2SO4质量分数0.8%、保持微沸状态30min的处理条件下,秸秆的糖含量达到最大值24.57%,最大氢气产量为141mL/g。     

玉米秸秆的渗滤式稀酸预处理

对玉米秸秆的渗滤式稀酸预处理进行了考察,通过对温度、酸浓度、渗滤速度、液固比等影响因素的实验分析,得到了优化的工艺条件:反应温度170℃,硫酸浓度0.25%,液固比为10:1,渗滤速度150mL/min,70%水解液排出后,渗滤速度降为100mL/min。水解液中木糖浓度达到22g/L,糖得率达到约80%。经过稀酸预处理后的玉米秸秆进行酶水解,纤维素转化率达到80%。     

NaOH/H2O2预处理促进玉米秸秆酶解产糖工艺条件的研究

采用正交实验初步探讨了NaOH/HO2O2对经白腐菌Hyrophous sp.254处理15 d的玉米秸秆进行预处理的最佳条件.在NaOH/H2O2预处理过程中,NaOH浓度、H2O2体积分数、底物浓度及预处理时间均对秸秆的纤维素酶酶解效率存在一定影响.试验表明,NaOH/H2O2的最佳预处理条件:NaOH浓度为7g/L,H2O2体积分数为0.7%,底物浓度为50g/L,处理时间为24h.在优化的工艺条件下,玉米秸秆的还原糖产量达到了0.417 g/g,H2O2用量减少了30%,废水排放量减少了60%.     

微波辅助NaOH预处理提高油菜秸秆酶解效率的研究

为提高油菜秸秆的酶解效率,试验借助于常压微波加热技术辅助NaOH预处理,并对处理条件进行了优化。结果表明,与未处理比较,经微波预处理的油菜秸秆致密结构明显破坏,利于被纤维素酶水解。微波辅助预处理的最优化条件:微波功率600 W,时间5 min,NaOH 0.1 mol/L,温度80℃,经预处理后的油菜秸秆酶解率可达28.09%,较未处理前增加2.75倍,显著提高了酶解效果。     

黑曲霉AS0006预处理玉米秸秆产沼气研究

为了提高玉米秸秆与牛粪混合发酵的产气效率,文章对黑曲霉AS0006预处理后的玉米秸秆进行了研究,考察了不同预处理时间的玉米秸秆在混合厌氧发酵过程中的日产气量、累积产气量、TS和VS去除率以及木质纤维素去除率等发酵特性的变化情况。研究结果表明:黑曲霉AS0006对木质纤维素有较强的降解能力,玉米秸秆经黑曲霉AS0006预处理28 d后,纤维素、半纤维素和木质素的降解率分别为26.86%,11.93%和25.09%;经过黑曲霉AS0006预处理的玉米秸秆与牛粪混合发酵可以提高日产气量并缩短厌氧发酵周期,其中,预处理21 d后的玉米秸秆的产气高峰最大,为523.4 mL/d;经过黑曲霉AS0006预处理的玉米秸秆与牛粪混合发酵后, TS和VS去除率以及木质纤维素去除率均比未经预处理的玉米秸秆高。     

有机钙盐预处理纤维素的热解试验研究

摘要：在管式炉上进行了预处理纤维素（CaFA纤维素）的热解实验,研究了预处理对纤维素热解特性的影响。样品红外压片分析显示预处理影响了纤维素组成单元吡喃环的稳定性,且CaFA纤维素出现了明显的羧酸根官能团振动。热解实验表明：预处理使得纤维素的半焦和气体产率增加,生物油产率下降。CaFA纤维素最大生物油产率为0.496(g/g),相比未处理纤维素最大生物油产率降低19.1%。CaFA纤维素的气体产物中,CO含量减少,而CO2、CH4和H2含量增加,一定程度上提高了热解气相产物中的氧含量。GC-MS分析表明预处理对纤维素生物油组分具有明显的选择性,CaFA纤维素生物油中,大分子糖类及其衍生物的相对含量显著减少,而小分子酮类物质明显增加。     

Experimental study on the interactions of supercritical CO2 and H2O with anthracite

To better understand the mechanism of interactions of supercritical CO₂ (SCCO₂) and H₂O, untreated, SCCO₂ treated and SCCO₂-H₂O treated anthracites were adopted to analyze changes in pore structure, adsorption capacity. Observations from experimental data reveal that mineral and other substances in the fractures and matrix of coal body are dissolved and mobilized by the carbonic acid formed from the mixture of SCCO₂ and H₂O, which may contribute to smaller pore development and enhance the adsorption capacity. These findings may provide new insights into effective and safe storage of CO₂ in coal reservoir.     

不同预处理方法对麦草纤维素酶解效果的影响

以麦草纤维素为研究对象,将其进行机械粉碎后,分别采用碱浸泡/蒸汽、蒸汽/碱浸泡、蒸汽、冷冻/蒸汽、碱浸泡/冷冻等方法进行预处理,然后加入纤维素酶进行酶解,通过检测酶解液中葡萄糖含量来评价麦草纤维素预处理的效果。研究结果表明,预处理后的麦草纤维素经NaOH溶液浸泡后,再用蒸汽处理40 min,酶解24 h后葡萄糖产率较预处理前的葡萄糖产率有明显增加(提高15%);经NaOH溶液浸泡后再进行超低温(-80℃)冷冻处理,酶解12 h后葡萄糖产率有所增加,酶解48 h后葡萄糖产率比预处理前提高23%。     

Experimental and numerical study on multi-wave modes of H2/O2 rotating detonation combustor

H₂/O₂ are desirable propellants for rocket-based rotating detonation engines but are rarely reported. This report presents an experimental study on rotating detonations powered by H₂/O₂. A non-premixed three-dimensional numerical simulation was conducted via OpenFOAM-based code. The experimental results revealed more than five co-rotating detonation waves at various flow rates with a propagation speed below 2000 m/s. Furthermore, an adjustment stage was observed prior to the stabilization of the detonation in the N-wave mode. The wavenumber in the adjustment stage varied between N and N+1 when the flow rate was 153 g/s and between N-1 and N+1 at 186 g/s. The simulation results revealed that multiple waves and low filling heights characterized the flow field of the H₂/O₂ rotating detonation. The severe deflagration of the contact surface led to new detonation waves at excessive filling heights. This supports further exploration of the potential application of H₂/O₂ propellants in rotating detonation rocket engines.     

Experimental and numerical study on laminar premixed NH3/H2/O2/air flames

Adding the product of water electrolysis (i.e. 2:1 volume of H₂ and O₂) is an effective strategy to enhance the combustion intensity of NH₃/air mixtures. In this work, the laminar burning velocity (LBV) of the obtained NH₃/H₂/O₂/air mixtures was measured at 303 K, 0.1 MPa and compared with the values predicted by seven mechanisms. To improve the prediction performance, a new mechanism is developed based on the existing mechanism and adopted for numerical simulation. The results of this study show that the LBV of NH₃ is significantly increased by additional H₂ and O₂. By comparison, it is found that H₂ shows a more significant promoting effect on LBV when the volume ratio of additional H₂ and O₂ is 2. The concentration of key radicals and the flame temperature increase remarkably due to the addition of H₂ and O₂, which promote the flame propagation. Furthermore, the experimental results also indicated that the additional H₂ and O₂ make the burned gas Markstein length decrease on the lean side and increase on the rich side.     

利用H2O2进行DPF再生的试验研究

作者在165FA柴油机试验台上对H2O2为DPF（柴油机微粒过滤器）辅助再生的各项性能进行了试验研究。试验结果表明，对于壁流式不锈钢丝网滤芯的过滤器，在较低的反应温度（300℃-500℃）下，通过在过滤器中喷入H2O2，可使DPF得到良好的再生效果。     

Interaction of O2, H2O and H2 with proton-conducting oxides based on lanthanum scandates

An interaction of components from the gas phase, containing gaseous oxygen, hydrogen and water, with the La_1–xSr_xScO_3–α oxides in the temperature range of 300–950 °С and partial pressure of 6.1–24.3 kPa 8.1–50.7 kPa has been studied using a high temperature thermogravimetric analysis. The effects of partial pressure of the gaseous oxygen, water and hydrogen on the apparent uptake level of protons with oxides has been found. The studies of incorporation processes of hydrogen from molecular hydrogen atmosphere into the structure of proton-conducting oxides based on strontium-doped lanthanum scandates were performed in the temperature range of 300–800 °C and hydrogen pressure of 0.2 kPa by means of the isotope exchange method with the equilibration of isotope composition in the gas phase. The protons and deuterons concentrations were determined for the La_0.91Sr_0.09ScO_3–α oxide. The existence of proton defects in the structure of studied oxides after the exposure in H₂O and H₂-containing atmospheres was revealed using the ¹Н NMR. The role of oxygen vacancies in the proton incorporation processes is considered in the present work.     

离子液体[BMIM]Cl-水体系中纤维素制氢试验研究

以纳米二氧化钛为原料,在130℃水热合成钛酸纳米管TNTs后,用1 mol/L硫酸浸渍,450℃焙烧制备了SO42-/TNTs固体酸催化剂,并用XRD,SEM对纳米TiO2,TNTs,SO42-/TNTs进行表征。将制备的SO42-/TNTs与氧化锌混合用于离子液体[BMIM]Cl-水体系中微晶纤维素制氢反应,考察了催化剂、离子液体水含量及反应温度等因素对氢气产量的影响。试验表明,与微孔分子筛HZSM-5相比,SO42-/TNTs更有利于纤维素制氢反应,在相同的催化剂用量下,后者的氢气产量比前者提高了约60%。试验还发现,同一催化剂在使用量不同时,所得氢气产量有很大差异,催化剂由50 mg增至150 mg后,氢气产量提高了近两倍,达到132.33μmol/(g.h)。离子液体加水量的多少对氢气产量也有很大影响,加水后氢气产量增多,但若加水过多氢气产量反而有所下降。     

Experimental analysis of the absorption and desorption rates of HCOOK/H2O and LiBr/H2O

This paper evaluates the absorption and desorption rates of a potassium/water binary mixture and compares them to those of lithium bromide/water. The experimental procedure involved small-scale absorption chiller test rig. Extensive instrumentation was used so that identical operating conditions could be obtained for all tests to ensure a good comparison. Analysis of results has shown that the absorption rates for potassium formate/water is approximately 5% lower than lithium bromide/water. The desorption rates of potassium formate/water was found to be higher than that of lithium bromide/water. Heats of absorption and condensation were also recorded. © 1998 John Wiley & Sons, Ltd.     

秸秆压缩块插孔纤维混凝土空心砌块墙体保温性能试验研究

采用热箱法测定了空心混凝土砌块和秸秆混凝土砌块的传热系数。试验结果表明:所测定单排单孔空心混凝土砌块平均传热系数K=1.78W/(m2.K),单排双孔空心混凝土砌块平均传热系数K=1.57W/(m2.K),秸秆压缩块混凝土砌块平均传热系数K=1.08W/(m2.K)。秸秆混凝土砌块作为墙体保温材料具有很好的隔热保温性能。