轻工业纤维素生物质过程残渣能源化技术

以农产品为原料的轻工业大都是典型的流程工业,在通过转化过程将原料转化为食品、饮料、添加剂、调味料、纸和中成药等产品的同时产生被称为过程残渣的固体废物与废料,如白酒糟、酒精糟、醋糟、甘蔗渣、中药渣、油粕、酱渣、菌渣和造纸黑液可熔渣等。这些残渣产生于特定的生产过程,富含纤维素、蛋白质或木质素,因此代表一种已经被集中的生物质资源。它们同时含水50%—80%、易腐烂变质、甚至呈弱酸碱性,因此是重要的环境污染源。本文着眼于轻工生物质过程残渣的高值化利用,分析指出富含纤维素的白酒糟、醋糟、甘蔗渣、中药渣、茶渣和造纸边角料等适合作为生物质能源而被转化利用,并根据资源特征提出了可能的技术路线。通过分别对热化学路线涉及的脱水干燥、燃烧发电与气化发电技术和集成乙醇发酵、沼气发酵的复合转化技术进行技术综述,最后针对不同规模的富含纤维素轻工生物质过程残渣能源化提供了技术选择建议。     

轻工业纤维素生物质过程残渣能源化技术

以农产品为原料的轻工业大都是典型的流程工业,在通过转化过程将原料转化为食品、饮料、添加剂、调味料、纸和中成药等产品的同时产生被称为过程残渣的固体废物与废料,如白酒糟、酒精糟、醋糟、甘蔗渣、中药渣、油粕、酱渣、菌渣和造纸黑液可熔渣等.这些残渣产生于特定的生产过程,富含纤维素、蛋白质或木质素,因此代表一种已经被集中的生物质资源.它们同时含水50%-80%、易腐烂变质、甚至呈弱酸碱性,因此是重要的环境污染源.本文着眼于轻工生物质过程残渣的高值化利用,分析指出富含纤维素的白酒糟、醋糟、甘蔗渣、中药渣、茶渣和造纸边角料等适合作为生物质能源而被转化利用,并根据资源特征提出了可能的技术路线.通过分别对热化学路线涉及的脱水干燥、燃烧发电与气化发电技术和集成乙醇发酵、沼气发酵的复合转化技术进行技术综述,最后针对不同规模的富含纤维素轻工生物质过程残渣能源化提供了技术选择建议.     

合成气气氛下褐煤与生物质共液化残渣的燃烧特性

利用热重研究了不同液化条件(溶剂、温度、气氛、水分)下褐煤与生物质共液化所得残渣的燃烧特性。通过比较共液化残渣燃烧的三个特征温度,着火点、燃烧峰温和燃尽温度,对比分析了液化条件对残渣燃烧特性的影响及其原因,同时研究了残渣燃烧的动力学。结果表明,四氢萘为溶剂所得残渣的燃烧特性好于甲苯为溶剂的;360℃下所得液化残渣燃烧反应性好于420℃下的;合成气气氛下所得液化残渣燃烧反应性好于氢气气氛下的;液化过程加入水后,所得残渣的燃烧反应性降低。不同液化条件下所得残渣的加氢程度和收率不同,使残渣具有不同的H/C原子比、比表面积和灰分,从而对残渣的燃烧特性产生影响。残渣的燃烧特性符合三段二级反应,大部分残渣三段活化能遵循"高-低-高"的变化规律。     

不同液化条件下生物质残渣的燃烧特性研究

对锯屑在不同液化条件（溶剂、气氛、温度、催化剂）下所得液化残渣在热天平上进行了燃烧特性研究,通过比较液化残渣燃烧的三个特征温度,着火点ti、燃烧峰温tp和燃烬温度tb,分析了液化条件对残渣燃烧特性的影响。同时通过热重曲线所得数据探讨了液化残渣燃烧过程的动力学,并计算了活化能和频率因子 。结果表明,不同溶剂下所得液化残渣的燃烧特性显著不同,以四氢萘为溶剂所得液化残渣具有较好的燃烧特性;不同气氛下所得残渣的燃烧特性没有明显的不同;350℃下所得液化残渣的燃烧特性要好于300℃下所得液化残渣的燃烧特性;由于催化剂的影响,加入1%Mo后降低了所得液化残渣的燃烧特性;液化残渣的燃烧反应符合两段一级反应动力学。     

煤液化残渣与生物质混合燃烧过程中硫污染物动态排放特性研究

生物质在全球总能源消耗中占有相当大的比例，世界各国对生物质能利用新技术的研究日益重视。用生物质燃料替代传统的化石燃料，不仅可以缓解日益严重的能源问题，也可以减少环境污染和降低CO2的排放心。但生物质的热值比较低，单独利用效率较低，因此一些欧美发达国家采取了将部分生物质与煤混和燃烧发电或气化的新技术。     

生物质热解油气化试验研究

生物质是一种环境友好可再生资源，可以通过多种途径转化为液体燃料。生物质热解液化即是在缺氧状态下对生物质进行快速加热，然后再对热解产物进行快速冷凝，最后获得一种称为生物油的液体燃料的技术。该技术以及生物油的特点主要有：热解液化温度为500℃，远低于生物质热解气化所     

纤维素类生物质厌氧发酵产氢的研究

以不同的天然堆肥作为产氢菌源,考察了不同纤维素类生物质废弃物的产氢能力.并以麦麸为供氢体,研究了产氢过程的代谢机制和生物液相组成的变化.实验结果证实,在最大产氢能力的批式实验条件下,不同底物的发酵产氢过程基本类似,生物相中氢和二氧化碳的体积分数分别为49%~62%和51%~38%,没有甲烷气体被检出.在此基础上,在5L混合反应器中以玉米秸秆为底物进行了产氢放大实验,产氢速率达0.8~1.2L/h.     

生物质气化技术的研究进展

生物质能是一种可再生能源,它来源于生物体(如植物、动物、微生物等)通过光合作用将太阳能转化为化学能,并以有机物的形式储存。生物质能可以在适当的条件下被转化为热能、电能、生物燃料等,是一种重要的替代传统化石能源的可持续能源。生物质气化作为生物质的开发路径之一,是利用生物质生产合成气的有效方式。本文综述了生物质气化技术的研究,包括传统气化技术、共气化技术、化学链气化技术以及超临界气化技术等。介绍了每个气化技术的实验研究,阐述了各个气化技术的特点;详细介绍了化学链气化中载氧体与共气化中掺杂剂的使用。本文旨在探索使生物质气化效率达到最优的方案,并列举了目前存在的局限性,为进一步发展生物质气化技术以及生物质气化研究提供有益参考。     

生物质在流化床中的热解和气化研究

在水蒸气及氮气流态化条件下 ,对不同生物质原料进行了热解气化实验 ,研究气体产物产率、成分随反应温度的变化规律。在一个常压鼓泡流化床实验台上 ,对五种生物质原料热解气化综合过程的气体产物产率及成分进行了测定。文中重点分析了原料SD2 0 1 (EucalyptusGlobulus锯末 )与SD2 0 2 (PinusRadiata锯末 )在水蒸气及氮气流化和不同温度条件下的热解气化特性 ,同时还分析了两种流化介质条件下生物质热解气化实验结果的差别。     

生物质气化技术发展分析

生物质气化技术在世界范围内得到了广泛应用.研究综述了生物质气化技术的发展现状和应用情况,阐明了生物质气化技术目前存在的主要问题;对中国生物质气化生活供气和工业供气典型项目的经济性进行了分析,在此基础上对中国生物质气化技术应用前景进行了展望;结合中国生物质气化产业发展面临的新形势,为生物质气化产业的发展提出建议.     

生物质流化床氧气-水蒸气气化实验研究

在小型流化床气化装置上进行了氧气-水蒸气气化实验,考察了原料、当量比、水蒸气配比、温度、二次风和床料对气化特性的影响。结果表明,原料中C和H含量越高,气化气中H₂和CO含量越高,焦油含量越低;当量比为0.27和水蒸气配比为0.6时,H₂含量达到最大值;温度的升高可提高H₂含量,在840 ℃以上,可提高CO含量;二次风从进料口偏上且二次风比率为15%通入,气体组分变化较明显,二次风通入点位置越高,焦油含量降低幅度越大;白云石和石灰石裂解焦油和提高H₂含量的活性高于橄榄石,但同时明显提高了气体中的灰分含量。     

生物质催化热解制取轻质芳烃

以轻质芳烃苯、甲苯、二甲苯和萘(BTXN)为目的产物,采用双颗粒流化床反应器对3种木材生物质进行了热解实验. 结果表明,木材生物质的初次热解终止温度低,有利于低温催化转化. 生物质中92%的挥发分在673 K时已释放完全,且生物质在初期热解得到的焦油经过二次分解反应可以转化为其它产物,通过有效控制生物质热解二次气相反应,能够改变其产物的分布,从而获得不同的目的产物. 生物质的催化加氢热解实验结果表明,催化剂种类和热解温度对加氢热解产物收率及其分布均有影响, BTXN是热解或加氢热解过程中二次气相反应的中间产物. 为了获得高产率的BTXN, 必须选择加氢活性适度的催化剂. 当CoMo-S/Al2O3催化剂作为流化介质进行加氢热解时,在863 K时, BTXN的收率可达6 3%(干燥无灰质量基准), 而NiMo/Al2O3催化剂表现出了很强的加氢活性, CH4的收率高达99 5%.     

生物质流化床富氧气化的实验研究

在常压流化床装置上进行了生物质在富氧条件下定向气化的实验研究。实验主要考察了氧的当量比和氧体积分数对气化气组成、碳转化率和气体热值的影响。当量比值是与温度紧密联系的一个量，本实验主要通过调节进料量来改变它的值，随着当量比的变化（0.21～0.29），燃气成分也会改变，其中变化最大的是H2、CO。H2体积分数显著增加，CO和CH4体积分数有降低的趋势，使燃气热值降低；氧体积分数是富氧气化过程中较重要的参数，在实验研究的范围内，发现增大氧气体积分数可以提高H2体积分数及有利于调节H2/CO(体积分数)的比值。当氧气体积分数从21％提高到45％，H2体积分数从20％增加到27.7％，H2/CO(体积分数)从0.38增加到0.75，比较接近合成液体燃料的气体比值。     

Novel Catalysts for Gasification of Biomass with High Conversion Efficiency

We have developed catalysts for the gasification of biomass with much higher energy efficiency than the conventional methods (noncatalyst, dolomite, and commercial steam reforming Ni catalyst). In our investigation, the Rh/CeO₂ gave high yields of syngas for cellulose gasification using a fluidized-bed reactor with batch feeding of cellulose. However, the catalyst was deactivated because of sintering of CeO₂ during the reaction. To prevent the CeO₂ sintering, we have further improved the catalyst and found that Rh/CeO₂/SiO₂ was quite stable for the gasification of cellulose. It was demonstrated that Rh/CeO₂/SiO₂ gave almost complete gasification of real biomass (wood powder) at 873 K. These results indicate that the combination of this kind of catalyst and fluidized-bed reactor can realize the energy-efficient biomass gasification.     

Prediction of the Behaviour of Biomass Ash in Fluidized Bed Combustors and Gasifiers

Two types of agricultural residues (wheat straw and olive residue) in untreated and pretreated (fractionation, leaching) form were tested as concerns their ash melting behaviour during fluidized bed combustion and gasification by means of thermal analysis techniques. The techniques applied included DSC, simultaneous DSC/TG and TG-MS for the determination of low-temperature ash melts and losses caused by the volatilization of alkali material. In combination with ash elemental analyses on the materials, the applied techniques proved to offer valuable information for prediction of the ash behaviour in fluidized bed reactors. This revised version was published online in August 2006 with corrections to the Cover Date.     

Oak Biomass in the Form of Wood,Bark, Brushwood,Leaves and Acorns in the Production Process of Multifunctional Biochar

Biochar from forest biomass and its remains has become an essential material for environmental engineering, and is used in the environment to restore or improve soil function and its fertility, where it changes the chemical, physical and biological processes. The article presents the research results on the opportunity to use the pyrolysis process to receive multifunctional biochar materials from oak biomass. It was found that biochars obtained from oak biomass at 450 and 500 °C for 10 min were rich in macronutrients. The greatest variety of the examined elements was characterized by oak-leaf pyrolysate, and high levels of Ca, Fe, K, Mg, P, S, Na were noticed. Pyrolysates from acorns were high in Fe, K, P and S. Oak bark biochars were rich in Ca, Fe, S and contained nitrogen. In addition, biomass pyrolysis has been found to improve energy parameters and does not increase the dust explosion hazard class. The oak biomass pyrolytic at 450 and 500 °C after 10 min increases its caloric content for all samples tested by at least 50%. The highest caloric value among the raw biomass tested was observed in oak bark: 19.93 MJ kg⁻¹ and oak branches: 19.23 MJ kg⁻¹. The mean and highest recorded K_{st max} were 94.75 and 94.85 bar s⁻¹, respectively. It can be concluded that pyrolysis has the potential to add value to regionally available oak biomass. The results described in this work provide a basis for subsequent, detailed research to obtain desired knowledge about the selection of the composition, purpose, and safety rules of production, storage, transport and use of biochar materials.     

Production of 5-Hydroxymethylfurfural and Furfural from Lignocellulosic Biomass in Water-Tetrahydrofuran Media with Sodium Bisulfate

5-Hydroxymethylfurfural (HMF) and furfural (FF), two bio-based platform chemicals, were produced from various raw lignocellulosic materials (corncob, corn stover, wheat straw, rice straw and sugarcane bagasse) in a water-tetrahydrofuran media by using NaHSO₄ as catalyst. The in fluences of reaction temperature (160-200 oC), reaction time (30-120 min), solvent volume ratio, feedstock concentration (2.4wt%-11.1wt%) and catalyst dosage were studied. The highest HMF and FF yields obtained from corncob were 47mol% and 56mol% under condition of 190 oC, 90 min, 10/1 of THF/H₂O. Besides, the lignin in the raw biomass wasalso depolymerized into organosolv lignin.     

Polish Varieties of Industrial Hemp and Their Utilisation in the Efficient Production of Lignocellulosic Ethanol

Nowadays, more and more attention is paid to the development and the intensification of the use of renewable energy sources. Hemp might be an alternative plant for bioenergy production. In this paper, four varieties of Polish industrial hemp (Białobrzeskie, Tygra, Henola, and Rajan) were investigated in order to determine which of them are the most advantageous raw materials for the effective production of bioethanol. At the beginning, physical and chemical pretreatment of hemp biomass was carried out. It was found that the most effective is the alkaline treatment with 2% NaOH, and the biomasses of the two varieties were selected for next stages of research: Tygra and Rajan. Hemp biomass before and after pretreatment was analyzed by FTIR and SEM, which confirmed the effectiveness of the pretreatment. Next, an enzymatic hydrolysis process was carried out on the previously selected parameters using the response surface methodology. Subsequently, the two approaches were analyzed: separated hydrolysis and fermentation (SHF) and a simultaneous saccharification and fermentation (SSF) process. For Tygra biomass in the SHF process, the ethanol concentration was 10.5 g∙L⁻¹ (3.04 m³·ha⁻¹), and for Rajan biomass at the SSF process, the ethanol concentration was 7.5 g∙L⁻¹ (2.23 m³·ha⁻¹). In conclusion, the biomass of Polish varieties of hemp, i.e., Tygra and Rajan, was found to be an interesting and promising raw material for bioethanol production.     

A Novel Energy-from-Waste Approach for Electrical Energy Production by Galvano–Fenton Process

A novel approach allowing the production of electrical energy by an advanced oxidation process is proposed to eliminate organic micropollutants (MPs) in wastewaters. This approach is based on associating the Galvano–Fenton process to the generation of electrical power. In the previous studies describing the Galvano–Fenton (GF) process, iron was directly coupled to a metal of more positive potential to ensure degradation of organic pollutants without any possibility of producing electrical energy. In this new approach, the Galvano–Fenton process is constructed as an electrochemical cell with an external circuit allowing recovering electrons exchanged during the process. In this study, Malachite Green (MG) dye was used as a model of organic pollutant. Simultaneous MG degradation and electrical energy production with the GF method were investigated in batch process. The investigation of various design parameters emphasis that utilization of copper as a low-cost cathode material in the galvanic couple, provides the best treatment and electrical production performances. Moreover, these performances are improved by increasing the surface area of the cathode. The present work reveals that the GF process has a potential to provide an electrical power density of about 200 W m⁻². These interesting performances indicate that this novel Energy-from-Waste strategy of the GF process could serve as an ecological solution for wastewater treatment.