The influence of storage and drying methods for Scots pine raw material on mechanical pellet properties and production parameters

Converting solid biomass into pellets through densification greatly improves logistical handling and combustion processes. Raw material properties can affect pellet quality. This study investigated how storage and drying methods for wood (Pinus sylvestris L.) used as a raw material for pellet production influenced pellet durability, bulk density and energy consumption. The pelletization experiments were performed using a Sprout Matador M30 press (nominal production capacity 3.5 tonnes/h). Results showed that pelletization of 11 months stored wood compared to fresh material and high drying temperature (450 °C) compared to 75 °C resulted in higher energy consumption, probably due to increased friction in the matrix caused by the loss of extractives. However, the pellets produced were of higher density than those made from fresh material dried at a low temperature. The latter had the highest durability. Increased energy consumption showed no correlation with pellet durability.     

Effect of biomaterial characteristics on pelletizing properties and biofuel pellet quality

Sawdust of conifers as a by-product from saw mills is the most commonly used biomaterial for pellet production in Sweden today. Experiences from the biofuel pellet industry indicate that different biomaterial properties influence the final pellet quality. A systematic study was conducted where five factors were varied according to a two level fractional factorial design. The factors were: tree species (Scots pine, Norway spruce); origin of growth-place (latitudes 57 and 64°N); storage time of sawdust (0 and 140 days), moisture content (9 and 12%) and steam treatment (2 and 6 kg/h). The measured responses bulk density and mechanical durability represented the pellet quality while the press current and the fines produced in the pelletizing process were measures of the pelletizing property.The results showed that low moisture content and long storage time resulted in increased bulk densities and press currents. For mechanical durability and fines, a long storage time and intermediate moisture contents were found favourable. In addition, indications were found that the reduction of fatty and resin acids during the storage also influenced the pelletizing properties and the pellet quality.     

Effect of moisture content, particle size and pine addition on quality parameters of barley straw pellets

Agripellets from barley straw wastes have been produced in an annular die pellet mill. The semi-industrial scale of the pilot plant allowed for measurement of the die temperature, and an accurate control of the straw moisture at the die inlet. The pellet mechanical durability, density, length and moisture were evaluated for pure straw and blended pellets, together with the heating value and the ash content. The composition of the raw material barely changed with the compaction process. Optimum moisture contents for dense barley straw pellets production proved to be in the range of 19-23%. A durability value of 95.5% was reached under these conditions, increasing to 97-98% when small quantities of pine sawdust were added (2, 7, and 12 wt.% of pine in straw). Agglomeration of the ground particles was improved by water and pine addition, while a coarser grinding did not show any negative effect on barley straw compaction.     

A systematic methodology for the environomic design and synthesis of energy systems combining process integration,Life Cycle Assessment and industrial ecology

This paper presents a systematic methodology for sustainable process systems design, combining the principles of industrial ecology, process design and process integration, Life Cycle Assessment (LCA) and multi-objective optimization (MOO). The superstructure considers an extended decision perimeter and embeds models based either on flowsheeting software or average market technologies, for which energy and material flows are extracted from the Life Cycle Inventory (LCI) database. Therefore, the overall supply chain can be synthesized within a given action system and the systematic recyclings identified. The methodology can be used to design eco-industrial parks or urban systems, to identify the best conversion pathways of resources or waste, or to fix the optimal value of environmental taxes. It is illustrated by an application to the environomic design of an urban energy system. This case study considers multiple energy services to be supplied and waste to be treated, with their seasonal variations, indigenous and imported resources, as well as different candidate conversion technologies. Results demonstrate that integrating an environmental objective in the design procedure leads to consider different system configurations than if only economic aspects are considered. The problematic of the optimal value of a CO₂ tax is as well addressed.     

Effect of waste matrix for the optimization of moisture content and calorific value of biodried material using Taguchi DOE

In this study, Taguchi approach was used to determine the influence of waste composition for the optimization of moisture content (MC) and calorific value (CV) of food waste via bio-drying process. The objective was to reduce MC and increase CV of the bio-dried material. The effect of three different levels of four factors including food (FW), paper (Pa), plastic (Pl) waste, and bulking agent (BA) were studied and optimized. The moisture content of the bio-dried material varied between 8.59 and 50.93%, whereas that of the calorific value was 11–25?MJ/kg. The results revealed optimum configurations for MC and CV as FW₁Pa₃Pl₃BA₃ and FW₁Pa₁Pl₃BA₁, respectively. Regression analysis revealed MC as a positive function of FW and BA with plastic positively correlated with calorific value. ANOVA analysis indicated that FW had more prominent effect on both MC and CV. The predicted and measured values were very close to each other. Additionally, the results realized in the confirmatory experiments at optimized conditions of CV was found to be higher than the test runs of Taguchi design, suggesting that Taguchi method was very successful in the optimization of bio-drying factors for MC and CV.     

污泥干燥焚烧系统能耗的影响因素分析

介绍了一种污泥干燥焚烧处置系统,分析了影响干燥焚烧系统能耗的因素。分析结果表明,污泥干燥机入口温度越高、污泥初始含水率越低、污泥干燥后含水率越高,污泥干燥焚烧系统能耗就越少,装机容量就越小,设备的外形尺寸就越小,干燥焚烧系统的一次性投资就越低。     

The influence of processing parameters on the structural and mechanical properties of drawn polypropylene fibres: A factorial design approach

This article reports a study of multi‐stage polypropylene fiber drawing (stretching) as a continuous, but independent stage of the overall fiber‐forming process. The fibers were drawn according to a factorial experimental design, once appropriate spinning conditions had been devised. The structures of the drawn fibers were studied using wide‐angle X‐ray diffraction and birefringence measurements. In addition, the fibers were characterized with respect to filament tenacity, elongation to break, specific secant modulus, and extent of shrinkage at 130°C. All these properties were quantitatively assessed as responses to nine specially selected process control parameters in the drawing equipment. For every property analyzed, the temperatures of the hot plates in the draw frame were found to exert no significant influence, whereas the temperatures of the initial rollers were in most cases significant. Furthermore, the speed of the final roller also played an influential role, and a number of interactions between process parameters were identified as significant. Explanations are advanced for the parts played by significant process parameters on the properties of the drawn fibers. The article also demonstrates the advantages of factorial experimental design in determining correct settings for process parameters to give drawn fibers with the properties desired. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Study on the effective process parameters influencing styrene and acrylonitrile grafting onto seeded polybutadiene latex

A series of experiments were designed and conducted to determine the significance of process parameters in the grafting of styrene and acrylonitrile onto polybutadiene seeds in a semicontinuous emulsion copolymerization system. The significances of the parameters were obtained by comparing the variance ratios, or F values, with F‐distributions. The significance level of each test (α‐value) was obtained by variance analysis. The important process parameters in industrial polymerization processes are usually monomer‐to‐polymer ratio, initiator type and concentration, chain‐transfer agent, and reaction temperature. The target responses were final monomer conversion, grafting degree, grafting efficiency, gel percent, and viscosity‐average molecular weight of free styrene‐acrylonitrile (SAN). The analysis of variance indicated that cumene hydroperoxide as the initiator and reaction temperature had strong effects on the graft structure. Moreover, free SAN molecular weight was significantly affected by the monomer/polymer ratio and cumene hydroperoxide and n‐dodecyl mercaptan as chain‐transfer agents. The raspberry‐like morphology of grafted acrylonitrile‐butadiene‐styrene (ABS) particles and phase separation within the particles were confirmed by transmission electron microscopy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of industrial microwave irradiation on the physicochemical properties and pyrolysis characteristics of lignite

The surface functional groups and pyrolysis characteristics of lignite irradiated by microwave were comparatively studied to evaluate the feasibility of using industrial 915 MHz for lignite drying. The drying kinetics, micro structure, chemical functional groups, re-adsorption properties, and pyrolysis characteristics of the dried coal were respectively analyzed. Results indicated that for typical Chinese lignite studied in this paper, 915 MHz microwave drying was 7.8 times faster than that of the hot air drying. After industrial microwave drying, the sample possessed much higher total specific surface area and specific pore volume than that of air dried sample. The oxygen functional groups and re-adsorption ratio of microwave irradiated coal decreased, showing weakened hydrophilicity. Moreover, during the pyrolysis of the coal dried by hot air and microwave, the yield of tar largely increased from 1.3% to 8.5% and the gas production increased correspondingly. The composition of the tar was also furtherly analyzed, results indicated that Miscellaneous hydrocarbons (HCs) were the main component of the tar, and microwave irradiation can reduce the fraction of polycyclic aromatic hydrocarbons (PAHs) from 26.4% to 22.7%.     

Effect of Solvent Content on the Separation and the Energy Consumption of Extractive Distillation Columns

This article sets out to evaluate the effect of solvent content in the extractive section on the separation efficiency and energy consumption of extractive distillation columns. Contrary to the classical approach, the proposed approach enables a simultaneous evaluation of the effect of the major decision variables (reflux ratio, solvent flow rate, and the number of stages of the extractive section [NSE]). The procedure allows calculating the minimum solvent flow rate for the separation and the minimum specific energy consumption. The results show that the minimum specific energy consumption is obtained for the minimum reflux ratio and not for the minimum solvent flow rate. Moreover, the results show that it is not always the case that a larger NSE results in lower energy consumption. Due to its industrial importance, the dehydration of aqueous mixtures of ethanol using ethylene glycol as solvent has been chosen as a case study.     

压延存料对PVC透明片材质量影响的探讨

根据G.Ardichuili的压延理论,分析了聚氯乙烯压延加工过程中物料的流变行为,指出存料是影响压延透明片材的厚度均匀性、外观质量的重要因素之一。根据产品的厚度、柔软率,正确控制辊隙存料量是提高压延透明片材质量的重要手段之一。     

硫化钙碳酸化制备硫化氢工艺参数的研究

研究了以磷石膏为原料烧制硫化钙和碳酸化硫化钙生产硫化氢的工艺路线,并用正交设计法找出了硫化钙碳酸化制备硫化氢的最优工艺参数.通过实验得到最优工艺参数为气流速度110个气泡/min、温度60℃、反应时间5 h,此时硫的转化率达93%.     

研磨体的形状、材质对粉磨效率的影响

介绍了国内外对研磨体的形状、材质对球磨机粉磨效率的影响试验情况和结论，在阐述异形研磨体节能降耗理论依据的基础上．进行了一系列生产实验和实践。结果表明：采用异形研磨体——含少量耐磨耐腐蚀的微量元素超高铬柱(棒或段)球，对于粉磨坚固矿石具有显著的增产、节能、降耗的效果。     

The influence of moisture content on the heat affected zone and the resulting in-plane shear strength of laser cut thermoplastic CFRP

Abstract

In this paper investigations on the effect of the moisture content of thermoplastic CFRP on the laser induced heat affected zone (HAZ) and the resulting in-plane shear properties are presented. For this purpose carbon fibre reinforced polyetherimide (PEI) and polyphenylene sulphide (PPS) sheets were conditioned to different moisture contents and were then used for laser machining test specimens with contour and multipass cutting strategies. The extents of the HAZ were measured and in-plane shear tests were performed, revealing that the shear properties decrease when cutting material with high moisture content. This behaviour can be correlated with the type of HAZ which contains porosity caused by the vapourisation of water.     

硫化钙碳酸化制备硫氢化钙的工艺参数研究

研究了以磷石膏为原料烧制的硫化钙碳酸化制备硫脲的中间产物硫氢化钙的工艺。用正交设计法找出了硫化钙碳酸化制备硫氢化钙的最优工艺参数:反应时间1.5h、温度30℃、气流速度80个气泡/min。在此条件下,硫的转化率达88.90%,并用制备的硫氢化钙合成了纯度为93.21%的硫脲。表明了以磷石膏为原料制备硫氢化钙生产硫脲是可行的。     

变温聚合工艺对聚合反应速率及PVC树脂性能的影响

分别采用恒温和变温聚合工艺合成聚氯乙烯(PVC)树脂,研究了PVC树脂的基本性能。结果表明:采用变温聚合工艺,在压力下降阶段提高聚合温度制备PVC树脂,可提高聚合反应速率,树脂热稳定性和颗粒性能合格。与恒温聚合工艺所制树脂相比,变温聚合工艺所制PVC树脂的聚合度下降约40,相对分子质量分布由2.05增至2.15,热稳定性略有提高;较宽的相对分子质量分布改善了树脂的加工性能,据此优化加工配方可使制品保持良好的力学性能。     

三氯乙酸生产工艺的研究和工业化生产

在催化剂作用下,对氯乙酸生产过程中产生的母液进行通氯氯化,生产出了三氯乙酸。     

The influence of grinding mechanism on the liberation characteristics of clinker minerals

This study deals with the characterization of narrowly sized fractions of clinker ground by ball mill and high-pressure grinding rolls. Chemical, physical and mineralogical characterizations were made by using XRF, laser sizing, Blaine, BET, SEM, and image analysis techniques. The emphasis was given to the preferential liberation of the constituent clinker phases. High-pressure grinding rolls gave higher degrees of liberation of mineral phases arising from the intergranular breakage along the grain boundaries compared to ball mill grinding. This is expected to influence the downstream service properties of cement.     

The catalytic effect of the Na and Ca-rich industrial wastes on the thermal ignition of coal combustion

The catalytic effects of four industrial wastes, namely, the soap residue (SR), brine sludge (BS), calcium carbide residue (CCR), and white lime mud (WLM), on coal thermal ignition were investigated. The acidity of palmitate anion associated with Na⁺ in SR was lower than that of chloride anion combined with Na⁺ in BS, which resulted in an improved the combustion of SR. The acidity of OH^- anion combined with Ca²⁺ in CCR was lower than that of CO₃^2- anion combined with Ca²⁺ in WLM, resulting in CCR exhibiting a better catalytic effect on coal ignition. The alkaline metal Na had lower initial ionisation energy than the alkaline earth metal Ca. Therefore, the Na-rich SR exhibited higher catalytic activity on coal ignition than Ca-rich CCR. The ignition temperature of coal with 0.5% SR decreased from 544 to 503℃.     

电镀层均匀性的数值模拟及验证

采用数值模拟的方法,对电镀中电流密度的变化进行模拟,预测了镀层厚度变化的趋势,解释了这些变化产生的原因。并通过实验研究取样及在扫描电镜下对微观组织的观察,对模拟结果进行了进一步的验证。