水稻秸秆蒸汽爆破-酯化改性制备吸油材料

以水稻秸秆为原料进行蒸汽爆破-酯化改性制备溢油吸附材料。未改性水稻秸秆有一定的吸油能力,其饱和吸油倍率、吸水倍率分别为5.66 g·g^-1,7.59 g·g^-1。通过对水稻秸秆进行蒸汽爆破-酯化改性后,发现其亲油疏水性能得到显著改善。对酯化反应的影响因素进行系统考察,得到优化的改性条件为反应温度为80℃,催化剂对甲基苯磺酸酐浓度为0.75%,反应时间为6 h。改性后水稻秸秆吸油倍率为8.54 g·g^-1,吸水倍率为0.10 g·g^-1。对蒸汽爆破-酯化改性前后水稻秸秆材料进行BET、XRD以及FT-IR表征,发现爆破处理后材料的孔径增大;非结晶态以及乙酰基特征峰的出现说明水稻秸秆发生酯化改性反应。     

Effect of wheat straw ash on mechanical properties of autoclaved mortar

This study investigates the effect of wheat straw ash (WSA) on the mechanical strength of autoclaved mortar. The mechanical properties studied include compressive, tensile, and flexural strengths of mortar. Mortar mixes were prepared using natural silica, wadi (local sand), and crushed limestone fine aggregates at a w/c ratio of 0.6. Mortar specimens were exposed to autoclave for 2.5 h at a pressure of 2 MPa. Three percentages of WSA replacement levels (3.6%, 7.3%, and 10.9%) by weight of sand were utilized in the study. The study showed that the replacement of sand by WSA increases the mechanical strength of autoclaved mortar. Mortar specimens containing limestone aggregate with 10.9% WSA replacement level showed an average increase in compressive, tensile, and flexural strength by 87%, 67%, and 71%, respectively, compared to control mortar specimens. Scanning electron micrographs for autoclaved paste specimens containing 7.3% WSA replacement level revealed a more packed structure compared to control paste specimens.     

Surface modification of high calcium fly ash for its application in oil spill clean up

The present study aims at utilising an inorganic industrial by-product, high calcium fly ash (HCFA), in an environmental field: oil spill clean up. Properties, such as fine particle size, floating ability, hydrophobic character and porosity, make this material attractive for such a use. In order to investigate the oil sorption behaviour of HCFA an oil spill has been simulated, by using artificial ocean water and three types of oil (heating oil (HO), light cycle oil (LCO) and Iranian light crude oil (ILCO)). Two HCFA samples, a Ca-rich one (AD) and a Si-rich one (M), have been examined, so as to investigate the role of HCFA composition in its behaviour. The addition of HCFA to an oil spill results in the formation of a semi-solid oil–HCFA phase, allowing the quite total removal of oil from the water surface. HCFA’s oil sorption capacity in dry environment after 24 h is 0.7–0.9 g oil/g HCFA for AD and 0.5–0.6 g oil/g HCFA for M. HCFA’s behaviour, when added to an oil spill, necessitates the amelioration of its floating ability and affinity for oil and to this direction its hydrothermal treatment in an aqueous solution of sodium oleate (SO) under several conditions (time, temperature, HCFA:SO mass ratio, SO solution concentration, solution:HCFA ratio) has been applied. The treatment of the calcareous HCFA (AD) at 25 °C at a mass ratio HCFA:SO = 1:0.004 results in the formation of a cohesive semi-solid oil–HCFA phase, allowing the total removal of oil from the water surface, while the siliceous HCFA (M) requires a greater amount of SO (HCFA:SO = 1:0.5). The oil sorption behaviour of both HCFA and SO-modified HCFA seems to be related to the initial CaO content. During the treatment with SO, CaO is converted to calcite and calcium oleate, which contributes to the improvement of HCFA’s floating ability, due to its greater affinity for oil.     

Investigation of the effect of temperature and alkaline concentration on the solubilization of phenolic acids from dilute acid-pretreated wheat straw

This work deals with the investigation of the effect of alkaline concentration and temperature on the solubilization of phenolic materials from wheat straw, an abundant agricultural waste found in Turkey. The solid residue obtained after dilute acid pretreatment of wheat straw (SPWS) was treated by alkaline to solubilize the lignin to phenolic acids. Four different alkaline concentrations at 120 °C and seven different temperatures with 2 M NaOH were evaluated for the degree of solubilization of the phenolic materials, and the antioxidant activities of the soluble phenolic materials were determined. It was found that coumaric and ferulic acids were the major phenolic acids in all of the conditions tested. The highest antioxidant capacity of the hydrolysate of SPWS was obtained with 2 M NaOH at 150 °C where DPPH*, FRAP and TEAC values were found to be 3.23, 10.27 and 13.70 μmol/g WS, respectively.     

Oil spill response planning with consideration of physicochemical evolution of the oil slick: A multiobjective optimization approach

This paper addresses the optimal planning of oil spill response operations under economic and responsive criteria, with consideration of oil weathering process. The economic criterion is measured by total cost, while the measure of responsiveness is the time span of the entire response operations. A bi-criterion, multiperiod mixed-integer linear programming (MILP) model is developed that simultaneously predicts the optimal time trajectories of oil volume and slick area, transportation profile, response resource utilization levels, cleanup schedule, and coastal protection plan. The MILP model integrates with the prediction of an oil weathering model that accounts for oil physicochemical properties, spilled amount, hydrodynamics, and weather conditions. The multi-objective optimization model is solved with the epsilon-constraint method and produces a Pareto optimal curve that reveals how the optimal total cost and response operations change under different specifications of responsiveness. We present two illustrative examples for oil spill incidents in the Gulf of Mexico and New England.     

Analysis of the behaviour of pollutant gas emissions during wheat straw/coal cofiring by TG-FTIR

The behaviour of pollutant gas emissions during the firing of wheat straw and coal blends was examined experimentally by using thermogravimetric analysis (TGA). Typical anthracite coal and wheat straw in central China were selected in this study. The ratio of coal to wheat straw by mass was set as 10:90, 15:85, 40:60 and 60:40 and the firing was carried using simulated air with oxygen and nitrogen gases. The emission characteristics of gas pollutants such as HCl, SO₂, CO₂ and NO_x were determined by coupled Fourier transform infrared (FTIR) measurements. The results showed that HCl, SO₂, CO₂ and NO_x emissions were closely related to the volatile combustion and char reacting stages. HCl emission was mainly released during the volatile combustion at the temperature between 220 and 450 °C. The profiles of HCl against temperature exhibit a single-peak, and the HCl peak occurred at 310 °C for all blends no matter what the ratio. The emission profiles of SO₂, and NO_x against temperature had the characteristic of two peaks. The first peak occurred around 320 °C for all blends, and however the second peak shifted towards higher temperatures as the coal content was increased in the blends. The study showed that combining the straw and coal can produce better emission control by reducing the magnitude of the peak releases. The analysis showed that the blended sample with 40% coal and 60% straw by mass produced the lowest levels of HCl, NO_x and SO₂ gas emissions. The CO₂ emission was mainly produced in the char combustion stage and purely increased with the carbon content in the blends.     

小麦秸秆接枝丙烯酸制备高吸水性树脂

以N,N'-亚甲基双丙烯酰胺为交联剂,过硫酸钾一硫代硫酸钠为引发剂,采用水溶液聚合法合成了小麦秸秆接枝丙烯酸系列高吸水树脂。研究了单体配比、丙烯酸中和度、引发剂及交联剂用量对吸去离子水的影响。结果表明,该树脂具有良好的吸水性能,吸收去离子水达617 g/g。     

Physical and frictional properties of non-treated and steam exploded barley, canola, oat and wheat straw grinds

During storage and handling, accurate knowledge of the physical and frictional behaviors of biomass grinds is essential for the efficient design of equipment. Therefore, experiments were performed on non-treated and steam exploded barley, canola, oat and wheat straw grinds to determine their coefficient of internal friction and cohesion at three hammer mill screen sizes of 6.4, 3.2 and 1.6 mm, three normal stress values of 9.8, 19.6 and 39.2 kPa at 10% moisture content (wb). At any specific hammer mill screen size, the geometric mean particle size and bulk density of non-treated straw was significantly larger than steam exploded straw. The bulk density of ground straw significantly increased with a decrease in hammer mill screen sizes. The steam exploded straw grinds resulted in higher coefficient of internal friction compared to non-treated straw grinds primarily because of lower bulk densities. The coefficient of friction for non-treated barley, canola, oat and wheat straw were in the range of 0.505 to 0.584, 0.661 to 0.665, 0.498 to 0.590, and 0.532 to 0.591, respectively. Similarly, the coefficient of friction for steam exploded barley, canola, oat and wheat straw were in the range of 0.562 to 0.738, 0.708 to 0.841, 0.660 to 0.860, and 0.616 to 1.036, respectively, which were higher than non-treated straw of the kind. Power, logarithmic or exponential equations were developed to predict the coefficient of internal friction and cohesion with respect to average geometric mean particle sizes for non-treated and steam explode barley, canola, oat and wheat straw grinds.     

A novel method of utilizing the biomass resource: Rapid liquefaction of wheat straw and preparation of biodegradable polyurethane foam (PUF)

In the paper, wheat straw was rapidly liquefied in the mild condition. The optimum liquefaction effect was obtained at steam-explosion pre-treatment of wheat straw, liquefaction temperature of 140 °C, solvent/wheat straw ratio of 6:1, glycol (EG):glycerol = 5, sulfuric acid of 5%, and wheat straw of water content of 150%. During the liquefaction, cellulose, semi-cellulose and lignin are decomposed, which results in changes of hydroxyl value, acid value, viscosity and weight-average molecular weight of the reaction system. The liquefaction product was used to prepare polyurethane foam. Compared with the normal PUF, the foam had similar mechanical properties and better water absorption and biodegradability.     

小麦秸秆催化液化工艺研究

常温常压下小麦秸秆催化液化制绿色化学品。分别研究了小麦秸秆在甲醇、乙醇、丙三醇和丁醇中的液化效果,考察了甲醇和苯酚的混合体系下液化时间与不同催化剂对液化产率的影响。结果表明,常温常压下,4种醇对小麦秸秆的液化产率的高低顺序:甲醇>乙醇>丙三醇>丁醇,甲醇的液化产率最高,达到17.23%,可以作为木质素液化的有效试剂。甲醇和苯酚混合液化体系的液化产率可达到24.52%,以对甲苯磺酸作为催化剂液化产率可达到28.40%。     

Effect of ultrasonic assisted KOH pretreatment on physiochemical characteristic and anaerobic digestion performance of wheat straw

In this study, ultrasonic field was applied during potassium hydroxide (KOH) pretreatment of wheat straw (WS). Three concentrations of KOH (2%, 4%, and 6%) were tested during pretreatment. The results showed that there was a significant influence of the ultrasonic assisted KOH pretreatment (KOH_Upt) on physiochemical characteristics of WS during pretreatment as well as on digester performance. The pretreatment time was optimized to 36 h for all KOH concentrations. The highest total volatile fatty acid (TVFA) productions (3189 mg·L⁻¹) from 6%KOH_Upt samples were observed. Similarly, the SEM analysis and FTIR observation revealed that KOH_Upt effectively disrupted the physical morphology of WS and successful breaking of lignin and hemicellulose linkage between carboxyl groups. Moreover, the highest biogasification (555 ml·(g VS_loaded)⁻¹) and biomethane productions (282 ml·(g VS_loaded)⁻¹) from 4%KOH_Upt digesters, with 69% of biodegradability, indicated significant availability of organic matter from KOH_Upt. The R² values (0.993–0.998) in Modified Gompertz Model indicated that the model was feasible to predict methane yield for this study. Similarly, the B_o values for 4%KOH_Upt (283.30 ± 2.74 ml·(gVS_loaded)⁻¹) were also in agreement to the experimental methane yield. These results suggested that ultrasonic addition during KOH pretreatment of WS can effectively increase the organic yield during pretreatment. Moreover, the increase in methane production from 4% KOH_Upt suggested that digester performance can be improved with lower KOH concentrations using this pretreatment.     

麦草酶解木素的制备影响因素的研究

在有关酶解木素研究的基础上，详细研究了球磨时间、酶用量、底物浓度、酶解时间等因素对麦草酶解木素制备的影响．考虑到球磨时间对木素结构的可能变化的影响和尽可能地获得更大的木素提取率，提出了一个合适的麦草酶解木素的提取方法。     

Pyrolysis of wheat straw in a thermogravimetric analyzer: Effect of particle size and heating rate on devolatilization and estimation of global kinetics

The influence of different parameters such as particle size, initial weight of the sample, and heating rate on the devolatilization of wheat straw particles have been studied using thermogravimetric analysis. In addition, the variations in proximate analysis with different particle sizes of wheat straw have also been investigated. Results show that the curves corresponding to the third stage of pyrolysis differ for variations in particle size, initial weight, and heating rate of the pyrolysis process. A devolatilization model with three parallel nth-order reactions has been considered to determine the global kinetic parameters using thermogravimetric data. The kinetic parameters such as activation energy (kJ/mol), frequency factor (1/min), and order of the reaction for the three stages considered in devolatilization model were E₁ = 69, E₂ = 78, E₃ = 80; k₀₁ = 2.57 × 10¹², k₀₂ = 3.97 × 10⁷, k₀₃ = 3.17 × 10⁶; and n₁ = 2.3, n₂ = 0.65, n₃ = 2.7, respectively. It was noted from the order of the reaction that the second stage of the pyrolysis curve corresponds to the degradation of cellulose and hemicellulose, and the third stage to the lignin degradation.     

带底油(薄油环)凝析气藏数值模拟中混合网格的处理方法

带底油(油环)凝析气藏的数值模拟中,网格的划分对底油(油环)的描述起着很重要的作用。由于地层倾角的存在,常规的顺层网格经常会出现油气或油水界面在同一个网格内,甚至油气、油水界面在同一网格的情况,饱和度变化不连续,不能很好地描述油环油的分布;加密网格虽然在一定程度上减轻了这种现象,但是网格过多,影响数值模拟计算效率。本文针对底油(油环)的水平分布形态,建立了在气顶部分为顺层网格,底油(油环)和底水(边水)部分为水平网格的混合网格形式,很好地保证了底油(油环)的分布形态。同时,通过渗透率的转换,使水平网格部分的流体流动特性与地质上一致,有效地描述底水锥进薄油环以及油进入气藏的动态过程。通过对模型的模拟计算,验证了这种方法的可靠性。     

Effect of ultrasound on the physicochemical properties of organosolv lignins from wheat straw

The extractability and physicochemical properties of the wheat straw lignins were comparatively studied by using extraction methods with 0.5M NaOH in 60% aqueous methanol with and without application of ultrasonic irradiation. The results showed that applying sonication for 5, 10, 15, 20, 25, 30, and 35 min solubilized 67.4, 68.6, 74.4, 77.3, 77.3, 77.9, and 78.5% of the original lignin, whereas the treatment with 0.5M NaOH in 60% aqueous methanol at 60°C for 2.5 h without ultrasound assistance released 61.0% of the original lignin. The lignin preparations isolated by ultrasound‐assisted extractions showed slightly lower molecular weights, associated polysaccharides, and thermal stabilities during the initial stage of decomposition. More important, there were no significant differences in the primary structural features between the lignin preparations. Ultrasound‐assisted extractions under the alkaline organosolv extractions did not affect the overall structure of the lignin from wheat straw. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2512–2522, 2002     

海上溢油清理及其施工的职业健康安全

对海上溢油的原因及对环境的污染危害、溢油的清理方法进行了阐述,提出海上溢油清理施工存在职业健康安全风险,通过对危险、危害的识别、评价,准确确定危险源,有针对性的对风险进行控制。从而得出海洋溢油清理企业员工安全健康管理体系的构建和完善与员工的满意度有着密切的联系。     

麦草化机浆制浆规律的研究

研究麦草磺化化机浆的制浆规律并且从制浆得率和纸浆强度、白度出发,提出了麦草化机浆合适的化学预处理工艺条件。麦草磺化化机浆采用如下的预处理条件可以获得较高的制浆得率和较好的浆张物理性能：NaOH1％,Na2SO38％,最高温度140℃,保温时间30min,液比1：6。此时浆得率84％,裂断长3．34km,撕裂指数2．21mNm2·g-1,刚破指数2．87kPam2·g-1,白度22．8％（ISO）。     

Investigation of the effect of agglomeration time, pH and various salts on the cleaning of Zonguldak bituminous coal by oil agglomeration

In this study, the effects of bridging liquid concentration, agglomeration time, pH and various salts on the combustible recovery and ash contents of the agglomerated products have been investigated. Kerosene was used as bridging liquid. The optimum values of kerosene concentration, pH and agglomeration time have been determined as 20 wt%, 7.5 and 15 min, respectively. Metallic salts, such as FeSO₄, NaCl, FeCl₃, Al₂(SO₄)₃ were used in the experiments in which the effects of salts were investigated. While the combustible recovery slightly increased depending on the increase in the concentration of NaCl, very small decreases have been recorded in the recoveries depending on the increase in the concentration of the FeCl₃. A considerable reduction occurs in the agglomeration recovery with the increasing concentration of FeSO₄, while the combustible recovery slightly decreases at low concentration of Al₂(SO₄)₃.     

小麦秸秆水热预处理半纤维素降解动力学研究

水热预处理是木质纤维素原料高效能源转化的主要工艺流程之一,但是以小麦秸秆为原料的水热预处理的反应路径与反应机理仍有研究不足之处,制约该预处理过程的优化及实际生产应用。本文以小麦秸秆为研究对象,实验研究了木质纤维素水热预处理过程反应动力学。研究发现,在水热预处理过程中,小麦秸秆的主要降解过程是半纤维素降解产生低聚木糖、木糖以及糠醛的过程,半纤维素在水热过程中几乎完全降解。随着预处理温度的升高,水解液中低聚木糖和木糖的浓度降低,而糠醛的浓度增加;随着保温时间的延长,低聚木糖与木糖的浓度先增加后减小,糠醛的浓度会趋于稳定。根据实验结果提出反应路径并拟合获得动力学速率常数和反应活化能,所获的动力学模型可以很好地解释反应物浓度的变化,与实验数据吻合良好。该模型可以为小麦秸秆水解预处理系统的设计提供参考。     

小麦秸秆对硝基苯的吸附动力学及热力学研究

采用批量吸附实验考察了小麦秸秆对硝基苯的吸附动力学及热力学行为。吸附平衡时间约为60 min,且在前20 min是吸附急剧增加的第一阶段。吸附动力学行为符合拟二级动力学方程,拟二级动力学方程拟合曲线的决定系数均大于0.99,说明拟合程度很好。Langmuir和Freundlich吸附等温线都能较好地拟合吸附过程。吸附热力学结果表明,该反应是自发、吸热并且熵变增加的过程,温度升高有利于吸附反应的进行。