生物质锅炉防高温氯腐蚀陶瓷涂层研究及应用

针对生物质锅炉受热面存在的高温氯腐蚀问题,在12Cr1MoVG钢片表面制备先驱体陶瓷涂层,模拟生物质锅炉受热面积灰中的碱金属氯盐腐蚀,对涂层试样和钢片试样在400℃、450℃和500℃温度下进行KCl盐膜高温腐蚀实验。实验结果表明:在高温下,KCl对12Cr1MoVG钢的腐蚀速率随温度升高而增加,腐蚀后产物主要为Fe₂O₃;涂层试样能显著抵抗KCl腐蚀。对涂层进行SEM-EDS分析后发现涂层截面完整致密,与基材结合良好,内部检测不到氯元素,涂层起到了保护基材的作用。将先驱体陶瓷涂层技术应用于某台130 t/h有氯腐蚀问题的水冷振动炉排生物质锅炉,运行半年结果显示涂层仍存在,对受热面起到了明显的防护效果。     

废旧含氯塑料热解及其能源利用研究

存在于城市生活垃圾中的含氯塑料（如PVC等）是造成垃圾焚烧电站设备腐蚀和二次污染的主要因素。本文对利用热重－差分分析仪对氯含量53．8％聚氯乙烯（PVC）和无氯高密度聚乙烯（HDPE）以及氯含量10％－46％氯化聚乙烯（CPE）热解特性进行了研究。根据含氯塑料分级热解的实验结果,提出了含氯塑料热解与残余物燃烧的工艺路线,并对基于该工艺路线的概念电站的性能进行了计算和分析。     

电站锅炉受热面高温氯腐蚀的机理探讨

燃煤电站锅炉受热面普遍存在高温腐蚀,对于高温腐蚀一直认为主要为硫酸盐和硫化物腐蚀,近年来发现,煤中氯对电站锅炉管高温氯腐蚀的作用亦不可忽视。文中着重对高温氯腐蚀的机理进行了探讨,并提出了一些需要更加深入研究的问题。     

生物质原料烘焙预处理研究

烘焙预处理是生物质气化或混合煤炭燃烧之前的预热处理过程。综述国外研究资料的基础上,建立了包括质量产率、能量产率、高热值、氧碳比、含水量、研磨能耗等6项参数在内的综合评价指标和标准,研究了草芦、秸秆、松木屑、锯末、柳树木屑等生物质原料的烘焙预处理方式。研究发现:松木屑、锯末、秸秆的理想烘焙条件为:烘焙时间0.5h,烘焙温度依次为250~275℃、250℃、230~250℃;柳树木屑的理想烘焙条件为:烘焙时间1h、烘焙温度230℃。草芦在各烘焙条件下均无法达到标准水平。     

木质纤维素类生物质稀酸水解技术研究进展

稀酸水解技术被广泛应用于木质纤维素类生物质制取燃料乙醇,是目前经济性最好的酶水解预处理技术.文章从稀酸水解工艺出发,综述了近年来稀酸水解技术中非常有发展前景的高温液态水和超低酸水解技术在国内外的研发现状,归纳了常用的5种水解反应器的处理性能,并对比分析了其优缺点,最后提出了稀酸水解技术在工艺及反应器设计方面的发展方向,为后续研究打下了基础.     

生物质燃烧设备高温腐蚀问题初探

针对生物质燃烧设备经常涉及的高温腐蚀问题,结合近几年来国内外相关领域对生物质燃烧有关高温腐蚀的研究发展,着重分析其相关的腐蚀机理,影响因素以及相应的减轻措施等。     

生物质酸催化两步水解反应的研究

以松木木屑为原料,在自行设计的连续水解反应装置中进行稀硫酸催化连续水解的研究。通过正交试验法对木屑水解的反应条件进行优化,得到分别以木糖和葡萄糖为目标产物的较优工艺条件;以正交试验得到的工艺条件为基础,对木屑两步水解反应进行单因素分析,得到的最佳工艺分别为:反应温度170℃,反应时间5min,酸浓度1%,液固比7和反应温度190℃,反应时间7min,酸浓度3%,液固比9;通过分析半纤维素和纤维素的水解情况,探讨半纤维素水解对纤维素水解的促进作用机理。     

生物质稀酸连续水解的研究

以生物质为基础的酒精生产转化过程主要有两部分:木质纤维生物质中的纤维素被水解生成还原糖和用还原糖的发酵生产酒精.考察了影响稀硫酸连续水解的主要因素:温度、稀硫酸质量分数、停留时间.实验结果表明,温度对水解的影响最大,停留时间次之,稀硫酸质量分数影响较小.升高温度可有效地减少停留时间,得到较高的糖质量浓度.当温度为200℃、稀硫酸质量分数为1.0%、停留时间为6min、液固比为10L·kg-1时,可得到比较理想的水解效果.     

生物质微米原料快速气化试验研究

以木屑和稻壳为试验原料,针对生物质气化热解技术开展研究。实验结果表明,CO、H₂、CH₄等是组成合成气的主要有效成分;反应终温对气化热解反应的结果影响较大。当反应终温从700℃上升至900℃时,合成气产率提升了39. 6%;原料含水率对合成气的组分构成也有影响,含水率越高,H₂占比越小,同时无效热值气体CO₂含量占比上升。     

Comparison of biomass feedstock supply and demand in Northeast Italy

This study uses Geographical Information Systems (GIS) to estimate woody biomass supply and demand in Northeast Italy. Demand is estimated using census data on boilers and supply calculations are derived from data on timber harvests and mill operations. The analysis is done with GIS using Large Scale Analysis at a broader resolution (for the entire region) and Small Scale Analysis at a finer resolution (for the Primiero valley only), with added information on tree species, road networks and logging systems. From large scale analysis demand results to be about 163 000 MWh, corresponding to about 71 000 tonnes per year of fuel, with a moisture content of 50 percent. As shown by results from a small scale analysis, the Primiero valley has a deficit of 21 400 MWh. A more thorough analysis shows that 93 percent of logging operations can be performed with cable cranes and that high quality chips derived from forest biomass amount to only 335 MWh of energy (20 percent of the total). The deficit calculated at a small scale confirms the value obtained in the large scale calculation.Analysis of the demand-supply balance will be helpful for decision makers and politicians and should be taken into account when allocating subsidies for new boilers or district heating.     

Microalgal biomass as a feedstock for bio-hydrogen production

In the present work, H₂ production from microalgal biomass via dark fermentation was optimized by response surface methodology (RSM). Substrate concentration and initial pH were varied from 3 to 117 g dry cell weight (dcw)/L and 4.2–9.8, respectively. During the fermentation, pH was not controlled. The optimal condition was found at 76 g dcw/L and initial pH of 7.4, under which yielded 31.2 mL H₂/g dcw. The results of ANOVA verify that the relationship between substrate concentration and initial pH was slightly interdependent or significantly interactive. Besides, the monitoring alkalinity and pH during the confirmation test clearly showed that dark fermentative H₂ production (DFHP) from microalgal biomass was feasible without addition of external alkaline owing to the disruption of cell wall, which provided buffer capacity (max. 3800 mg as CaCO₃/L). Therefore, although it involved a batch test, this approach would promote the practical viability of DFHP from microalgal biomass. The main organic acids were acetic and butyric acids which are general metabolites found in successful DFHP.     

High dry matter whole-plant corn as a biomass feedstock

This research investigated the harvest, ambient pre-treatment, and storage of whole-plant corn as an alternative to conventional systems where corn grain and stover are fractionated at harvest. Harvesting the whole-plant, both grain and most of the above ground stover, after physiological maturity can reduce the intense logistics challenges typically associated with corn harvest and expand the harvest window. To determine the feasibility of the proposed system, corn was harvested at 350–840 g kg⁻¹ whole-plant dry matter (DM) using a forage harvester and then ensiled in pilot-scale silos. Ambient pretreatment during storage was investigated using both dilute acid and lime. Both pretreated and control whole-plant silages were very well conserved during anaerobic storage with DM losses generally less than 40 g kg⁻¹. Hydrodynamic separation of the grain and stover fractions after storage was found to be more effective at fractionating starch and fiber than conventional dry grain harvest, and both fractions had desirable composition. The effects of pretreatment on the silage were very pronounced at 30 and 100 g (kg DM)⁻¹ sulfuric acid loading with less than 100 g (kg DM)⁻¹ of the hemicellulose still bound in the cell wall at DM contents greater than 500 g kg⁻¹. The whole-plant harvest and storage system was shown to be a viable alternative to conventional corn grain and stover systems for producing feedstocks for biochemical conversion.     

Techno-economic assessment of pellets produced from steam pretreated biomass feedstock

Minimum production cost and optimum plant size are determined for pellet plants for three types of biomass feedstock – forest residue, agricultural residue, and energy crops. The life cycle cost from harvesting to the delivery of the pellets to the co-firing facility is evaluated. The cost varies from 95 to 105 $ t⁻¹ for regular pellets and 146–156 $ t⁻¹ for steam pretreated pellets. The difference in the cost of producing regular and steam pretreated pellets per unit energy is in the range of 2–3 $ GJ⁻¹. The economic optimum plant size (i.e., the size at which pellet production cost is minimum) is found to be 190 kt for regular pellet production and 250 kt for steam pretreated pellet. Sensitivity and uncertainty analyses were carried out to identify sensitivity parameters and effects of model error.     

A review of remote sensing methods for biomass feedstock production

Monitoring and maximization of bioenergy yield from biomass feedstock has recently become a critically important goal for researchers. Remote sensing represents a potential method to monitor and estimate biomass so as to increase biomass feedstock production from energy crops. This paper reviews the biophysical properties of biomass and remote sensing methods for monitoring energy crops for site-specific management. While several research studies have addressed the agronomic dimensions of this approach, more research is required on perennial energy crops in order to maximize the yield of biomass feedstock. Assessment of established methods could lead to a new strategy to monitor energy crops for the adoption of site-specific management in biomass feedstock production. In this article, satellite, aerial and ground-based remote sensing’s were reviewed and focused on the spatial and temporal resolutions of imagery to adopt for site-specific management. We have concluded that the biomass yield prediction, the ground-based sensing is the most suitable to establish the calibration model and reference for aerial and satellite remote sensing. The aerial and satellite remote sensing are required for wide converge of planning and policy implementations of biomass feedstock production systems.     

生物质热解燃烧过程Cl析出规律研究

用化学平衡软件“Factsage”计算了稻草秸秆在200～800℃温度范围内热解条件和500 ～900℃温度范围内燃烧条件下,与Cl相关的各种无机物质的热力学平衡分布.采用管式炉反应器,研究了秸秆在热解和燃烧条件下的Cl的析出规律.理论计算结果表明,当温度低于600℃时,Cl主要以固态KCl的形式存在;在温度超过600℃,热转化中Cl的气化析出随温度升高而增加,在氧化性气氛下该趋势加剧.管式炉实验与理论计算的生物质Cl析出率随温度升高的变化趋势总体吻合,但是析出份额上有显著差异.     

Decentralized drying-gasification scheme of sewage sludge with torrefied biomass as auxiliary feedstock

A drying-autothermal gasification scheme with torrefied biomass as auxiliary feedstock was proposed for the first time in order to realize the decentralized treatment of sewage sludge in wastewater treatment plant. Thermodynamic equilibrium and energy flow balance for the proposed system were evaluated. A non-stoichiometric thermodynamic equilibrium model was applied to evaluate the effect of adding ratio of torrefied biomass on the autothermal gasification performance. A novel dual-check algorithm was developed to determine the molar numbers of syngas components and the injected air. The energy utilization ratio for the whole process was introduced to measure the ratio of the energy used in the whole system to the total input energy. High adding ratio of torrefied biomass was favor of lifting the cold gas efficiency, but it would lead to low energy utilization ratio in terms of sewage sludge treatment.     

水浸取-离子色谱法测定固体生物质燃料中氯含量的研究

介绍了测定固体生物质中水溶性氯含量的方法——水浸取-离子色谱法,试验了加料量、加热时间和加热温度对测定结果的影响。研究结果表明,水浸取可溶性氯的最佳条件是固体生物质燃料与水的比为1 g/50mL,在110~120℃下加热40 min。进行了方法重复性和加标回收率试验,对比了XRF法半定量直接分析的结果。试验结果表明,水浸取-离子色谱法操作简单、重复性好、准确度高,能满足固体生物质燃料中氯离子含量的测试要求。     

Development and application of BioFeed model for optimization of herbaceous biomass feedstock production

An efficient and sustainable biomass feedstock production system is critical for the success of the biomass based energy sector. An integrated systems analysis framework to coordinate various feedstock production related activities is, therefore, highly desirable. This article presents research conducted towards the creation of such a framework. A breadth level mixed integer linear programming model, named BioFeed, is proposed that simulates different feedstock production operations such as harvesting, packing, storage, handling and transportation, with the objective of determining the optimal system level configuration on a regional basis. The decision variables include the design/planning as well as management level decisions. The model was applied to a case study of switchgrass production as an energy crop in southern Illinois. The results illustrated that the total cost varied between 45 and 49 $ Mg⁻¹ depending on the collection area and the sustainable biorefinery capacity was about 1.4 Gg d⁻¹. The transportation fleet consisted of 66 trucks and the average utilization of the fleet was 86%. On-farm covered storage of biomass was highly beneficial for the system. Lack of on-farm open storage and centralized storage reduced the system profit by 17% and 5%, respectively. Increase in the fraction of larger farms within the system reduced the cost and increased the biorefinery capacity, suggesting that co-operative farming is beneficial. The optimization of the harvesting schedule led to 30% increase in the total profit. Sensitivity analysis showed that the reduction in truck idling time as well as increase in baling throughput and output density significantly increased the profit.     

Estimates of technically available woody biomass feedstock from natural forests and willow biomass crops for two locations in New York State

A Geographic Information System (GIS) was used to estimate the technically available woody biomass from forests and willow biomass crops within a 40 km radius of Syracuse and Tupper Lake, NY. Land cover and land use data were used to identify the available land base and restrictions were applied for slope, parcel size and designated wetlands. Approximately 222,984 oven-dry tonnes (odt) of forest biomass are technically available annually around Syracuse, from 165,848 hectares (ha) of timberland. There are 67,880 ha of agricultural land technically available for growing willow biomass crops, which could produce 38,181 odt yr^?1 if 5% of this land was used and yields were 11.25 odt ha^?1 yr^?1. There are approximately 215,300 odt of forest biomass technically available annually around Tupper Lake from 211,500 ha of timberland. There are 781 ha of technically available agricultural land in this area so willow biomass production would be minimal. While these two areas have different land cover and land use characteristics, both have the potential to produce significant amounts of woody biomass.