刮板输送机电动机功率的分析与计算

根据刮板输送机实际工作状况,充分考虑了刮板输送机的各种运行阻力,计算电动机功率。分析计算的结果与实际情况相符合,验证了电动机功率满足要求。     

Analysis of syngas production rate in empty fruit bunch steam gasification with varying control factors

Biomass gasification is a prevailing approach for mitigating irreversible fossil fuel depletion. In this study, palm empty fruit bunch (EFB) was steam-gasified in a fixed-bed, batch-fed gasifier, and the effect of four control factors—namely torrefaction temperature for EFB pretreatment, gasification temperature, carrier-gas flow rate, and steam flow rate—on syngas production were investigated. The results showed that steam flow rate is the least influential control factor, with no effect on syngas composition or yield. The gasification temperature of biomass significantly affects the composition of syngas generated during steam gasification, and the H₂/CO ratio increases by approximately 50% with an increase in temperature ranging from 680 °C to 780 °C. The higher H₂/CO ratio at a lower gasification temperature increased the energy density of the combustible constituents of the syngas by 3.43%.     

Evaluation of alternatives for the evolution of palm oil mills into biorefineries

Six alternatives for the conversion of an average Colombian palm oil mill (30 t h⁻¹ of fresh fruit bunches (FFB) into biorefineries were evaluated. The alternatives studied were: (C1) Production of biogas from the Palm Oil Mill Effluents (POME), (C2) Composting of empty fruit bunches (EFB) and fiber, (C3) Biomass combustion for high pressure steam combined heat and power, (C4) Pellets production, (C5) Biochar production and, (C6) Biochar and bio-oil production. The available biomass could result in up to 125 kWh of electricity, 207 kg of compost, 125 kg of pellet, 44 kg of biochar and 63 kg of bio-oil per metric ton of FFB. The global warming potential (GWP), eutrophication potential (EP), net energy ratio (NER), capital expenditures (CAPEX), operational costs (OPEX), net present value (NPV) and internal rate of return (IRR) were calculated for all the alternatives. GHG reductions of more than 33% could be achieved. Anaerobic digestion and composting contributed to 30% reduction of the EP. The CAPEX for all of the biorefinery alternatives studied varies between 0.7 $ t⁻¹ and 2.8 $ t⁻¹ of FFB. The OPEX varies between 1.6 $ t⁻¹ and 7.3 $ t⁻¹ of FFB. The NPV for viable scenarios ranged between 2.5 million and 13.9 million US dollars. The IRR calculated varied between 3% and 56% and the payback periods were between 3 and 8 years. The total extra incomes reached values up to 15.2 $ t⁻¹ of FFB. Overall the pellets production biorefinery was the preferred alternative.     

An overview of empty fruit bunch from oil palm as feedstock for bio-oil production

Empty fruit bunch (EFB) from oil palm is one of the potential biomass to produce biofuels like bio-oil due to its abundant supply and favorable physicochemical characteristics. Confirming the assertion, this paper presents an overview of EFB as a feedstock for bio-oil production. The fundamental characteristics of EFB in terms of proximate analysis, ultimate analysis and chemical composition, as well as the recent advances in EFB conversion processes for bio-oil production like pyrolysis and solvolysis are outlined and discussed. A comparison of properties in terms of proximate analysis, ultimate analysis and fuel properties between the bio-oil from EFB and petroleum fuel oil is included. The major challenges and future prospects towards the utilization of EFB as a useful resource for bio-oil production are also addressed.     

Hydrogen from empty cotton boll agro-waste via thermochemical route and feasibility study of operating an IC engine in continuous mode

Hydrogen can be cited as prospective source of clean power. In this work hydrogen rich syn-gas generated from the agro-waste, empty cotton bolls was injected into an IC engine in continuous mode along with gasoline. At the air-fuel ratio of 23.40, specific fuel consumption of 0.35 kg kWh^?1, the engine could be operated with higher efficiency than with gasoline alone. A distinct reduction in emission characteristics could also be seen. Empty cotton bolls derived after removal of cotton from the flower in field, was first studied for fuel properties. The reasonably high heating value (HHV) of 17.54 MJ kg^?1 suggested that it could be a precursor to hydrogen via two stepped thermo-chemical process. The first step involved slow pyrolysis of the biomass at 500 °C for 60 min at a heating rate of 10 °C min^?1 yielding 39.71% bio-char by weight. The C, H, N, S and O contents of the produced bio-char was 59.91, 2.91, 0.72, 0.47 and 35.99% respectively and its HHV was 26.7 MJ kg^?1. Steam gasification of this bio-char, at 700 °C and water flowrate of 7 mL min^?1 exhibited maximum hydrogen yield of 67.42% (v/v) in the syn-gas mixture. Subsequent enrichment of the gas using ethanolamine/ethylene diamine and KMnO₄ solutions resulted in more than 90% (v/v) hydrogen in the combustible gas mixture and the test engine could be effectively operated.     

基于空样式的网页水印方法

网页水印在网页版权保护和防仿冒篡改等方面具有重要应用,现有的网页水印技术主要是利用HTML对一些格式变化的不敏感性进行水印信息的嵌入,这类方法嵌入的水印信息与网页内容严重分离,水印的隐蔽性不强,容易受到攻击。文中提出一种新的基于空样式的网页水印方法,利用HTML对于没有定义的样式不做任何操作的性质,将水印信息转换为没有内容定义的空样式,并嵌入到网页的HTML代码中,使得水印信息与HTML代码联系紧密,隐蔽性强,不易被检测和攻击,同时拥有较大的水印信息容量。与现有方法相比,所提方法具有较大的优越性。     

城市景观中的缝与槽

缝与槽是线性艺术在城市景观中的表现方式,本文从线性艺术效果、虚实与光影、功能与建造三个方面进行研究与分析,使人们深入理解线性艺术在现代城市景观设计中的作用和效果。     

楼地面出现质量通病的原因及防治措施

根据多年来的工程理论研究和实践经验 ,对目前普遍存在的楼地面质量通病的原因进行了探讨 ,并提出了具体的防治措施     

Liner services network design and fleet deployment with empty container repositioning

Transportation demand of shipping container fluctuates due to the seasonality of international trade, thus, every 3–6 months, the liner company has to alter its current liner shipping service network, redeploy ships and design cargo routes with the objective of minimizing the total cost. To solve the problem, the paper presents a mixed integer linear program model. The proposed model incorporates several relevant constraints, such as weekly frequency, the transshipment of cargo between two or more service routes, and transport time. Extensive numerical experiments based on realistic date of Asia–Europe–Oceania shipping operations show that the proposed model can solve real-case problems efficiently by CPLEX. The results demonstrate that the model can reduce ship’s capacity consumption and raise ships’ capacity utilization.