除水器及其在船舶燃油净化系统中的应用

船用燃油中不可避免地混入了海水及由此给柴油机带来的危害,应引起船东的足够重视。简要介绍了几种燃油除水器,并提出了船舶柴油机上应采用具有分水、分杂等多重功能的燃油净化系统之建议。     

Some considerations about bioethanol combustion in oil-fired boilers

The combustion of bioethanol in boilers has been analyzed and compared with conventional liquid fuels. The study includes an experimental evaluation of combustion performance as well as the estimation of the impact of replacing gasoil by ethanol on the thermal efficiency of an industrial boiler.Several works have been dedicated to the study of fuel substitution in internal combustion engines, being the use of gasoil-bioethanol blends in engines a common practice. However, very few studies have addressed the characterization of switching of conventional liquid fuels by bioethanol in boilers.Combustion tests demonstrate significant differences between bioethanol and gasoil flames. Soot, NO_x and SO₂ emissions are significantly lower with ethanol, whereas this fuel can produce higher amounts of CO than gasoil if the burner is not properly adapted. The experimental tests have demonstrated that both the burner and boiler operation should be readjusted or modified as a result of the change of fuel in industrial boilers. If thermal input is to be kept constant, nozzles of larger capacities must be used and the air feeding rate needs to be significantly modified. Also, the flame detector may have to be replaced and the fuel feeding system should be revised due to the enhanced tendency of ethanol to cavitation. Using the same thermal input may not guarantee keeping the same steam production, but some parameters of boiler operation should be modified in order to avoid reductions in the capacity of the boiler when switching from gasoil to bioethanol, such as gas recirculation fraction, steam cooling systems and percentage of oxygen in the exhaust gases.The feasibility of burning bioethanol in gasoil boilers has been analyzed, and the results confirm that fuel switching is technically possible and offers some advantages in terms of pollutants reduction.     

Catalytic cracking of mixtures of model bio-oil compounds and gasoil

Key model bio-oil O-compounds representing some of the major oxygenate groups, such as acetic acid, hydroxyacetone and phenol, were mixed with a standard gasoil and tested under fluid catalytic cracking (FCC) conditions in a laboratory-scale unit using an industrial FCC equilibrium catalyst (E-CAT) and a mixture of E-CAT and ZSM-5 additive. As a general trend, acetic acid, phenol or hydroxyacetone when mixed with a conventional gasoil increased the overall conversion, defined as fraction of the feed converted into gases, gasoline and coke, reduced the coke yield and increased fuel gas, LPG and gasoline. The conversion of the gasoil itself over pure E-CAT was not altered significantly by the presence of these compounds. This result could be interpreted by a preferential adsorption of the feed on the catalytic surface instead of the oxygen containing compounds. On the other hand, the ZSM-5 additive effect was attenuated in the presence of the O-compounds, suggesting a preferential interaction of such compounds with the ZSM-5. Up to 10 wt.% of these O-compounds studied can be processed without major problems in a FCC unit except for phenol.     

Effect of Exhaust Gas Temperature on Oxidation of Marine Diesel Emission Particulates with Nonthermal-Plasma-Induced Ozone

Because the regulations governing diesel engine emissions are becoming more stringent, effective aftertreatment is needed for particulate matter. Although diesel particulate filters (DPFs) are a leading technology used in automobiles, there remains a problem with DPF regeneration for marine diesel engines that use heavy oil fuel. In the present study, pilot-scale experiments were conducted to develop a particulate oxidation technology for marine diesel engine emissions using DPF regeneration by nonthermal-plasma-induced ozone injection. It has been shown that particulate oxidation depends on the exhaust gas temperature, and regeneration can be performed most effectively at a temperature of approximately 300 °C.     

生物油的特性、提质及应用

生物油是一种由生物质直接转化为液体燃料的新型可再生能源,具有产量大、可储存和碳循环等优点。综述了国内外生物油的物性特点、提质以及应用等研究进展。结果表明,生物油作为化石燃料的替代燃油存在很大优势,但其热值低、腐蚀性强等缺陷仍需进一步改进。     

A life cycle assessment of advanced biofuel production from a hectare of corn

Conventional agricultural life cycle assessments (LCAs) measure greenhouse gas (GHG) emissions for biofuel pathways as the amount of carbon dioxide equivalent emitted per unit of energy provided by the pathway (i.e. gCO₂e/MJ). This measure of GHG emissions, as computed by the Environmental Protection Agency (EPA) is then used to determine the extent to which the corresponding biofuel pathway complies with the GHG emission standards set forth by the Energy Independence and Security Act (EISA) of 2007. Under current legislation, ethanol produced from corn grain is prohibited from qualifying as an advanced biofuel, even if it were to meet the GHG emission standards. This paper proposes a measure of GHG emissions based on a unit of land rather than the energy provided by a biofuel pathway utilizing only one feedstock. A hectare of corn thus provides two feedstocks for the biofuel pathway considered here; corn grain is used for production of ethanol while corn stover is subjected to fast pyrolysis for production of biochar and bio-oil. The bio-oil is then subsequently upgraded to a fuel suitable for use as a drop in fuel in internal combustion engines. A LCA of this pathway is conducted and it is found that such a pathway generates a 52.1% reduction in GHG emissions. This is a reduction that is sufficient to qualify the combined output of a hectare of corn as an advanced biofuel if the current restriction in EISA were removed.     

Rheology and fuel properties of slurries of char and bio-oil derived from slow pyrolysis of cassava pulp residue and palm shell

Three bio-oil samples, namely, raw bio-oil from pyrolysis of cassava pulp residue (CPR), separated oil phase and aqueous phase of bio-oil from pyrolysis of palm shell (PS), were used as suspending media for preparing slurries of bio-oil and the co-product char. Rheologies of all tested slurries exhibited pseudoplasticity with yield stress and the degree of this non-Newtonian behavior depended on such parameters as slurry type, solid concentration, particle size and slurry temperature. Overall, char/bio-oil slurries gave better fuel properties including higher pH and reasonably high calorific value (18?C32 MJ/kg) as compared to their bio-oil properties. Combustion of char/bio-oil slurries occurred in the temperature range similar to their solid char combustion and without ignition delay.     

生物油的组成和提质研究的进展

生物油即生物质裂解油,具有原料充足、可再生、价格低廉、提质后作为液体燃料利用热值高和污染较小等优点,因而生物油提质技术成为能源化工领域研究的热点之一。了解生物油的组成可以提供生物油提质的重要信息。评述了生物油的组成和提质研究的进展,总结了存在的问题,预测了今后的发展方向。     

微波辅助下热解麦秆制取生物油的分析

采用微波辅助条件下热解稀硫酸预处理的麦秆制取生物油,产物采用分级萃取进行固液分离,依次分离出了环己烷萃取物、乙酸乙酯萃取物、甲醇萃取物和四氢呋喃萃取物,并用气相色谱/质谱联用仪（GC/MS）分析了各级萃取物。结果表明,本研究制取的生物油中化合物种类较少,有利于生物油中高附加值化学品的分离,其中5,6-二氢吡喃-2-酮在环己烷萃取物中的相对含量为45.0%,糠醛在生物油总产物中的相对含量为45.6%。此外,生物油中酸的相对含量为16.0%,表明该生物油含酸量高而不易于直接作为燃料油使用。     

Combustion of bio-oil ethanol blends at elevated pressure

This paper reports an investigation on the combustion performance of bio-oil/ethanol blends. Experiments were conducted in a constant volume vessel operating at a pressure of 25 bar and temperature 1100 K. Bio-oil produced via the fast pyrolysis of a spruce feedstock was blended to ethanol to form three stable blends containing 10%, 20% and 40% bio-oil by weight. In addition, ethanol and standard automotive grade diesel were tested as reference fuels. Measured vessel pressure was used in a single-zone heat release analysis, while two-colour optical pyrometry was used to investigate particle loading and temperature. Results show that for similar injections of fuel energy, use of up to 20% bio-oil in ethanol has limited impact on the performance of ethanol while 40% bio-oil in ethanol produced instability in the pressure trace near the end of the combustion process. Burning rates are similar for blends and ethanol. Addition of bio-oil to ethanol was found to increase combustion generated particle load, and this increased with bio-oil concentration, but remained much lower than particle concentration in diesel. Addition of bio-oil also resulted in formation of char particles that appear as luminous clusters outside the boundary of the spray. This suggests these particles will cool rather than oxidize. The presence of unburnt char particles in large numbers may have consequences for bio-oil as an alternative diesel fuel.     

An investigation into propane homogeneous charge compression ignition (HCCI) engine operation with residual gas trapping

Propane is available commercially for use in conventional internal combustion engines as an alternative fuel for gasoline. However, its application in the developing homogeneous charge compression ignition (HCCI) engines requires various approaches such as high compression ratios and/or inlet charge heating to achieve auto ignition. The approach documented here utilizes the trapping of internal residual gas (as used before in gasoline controlled auto ignition engines), to lower the thermal requirements for the auto ignition process. In the present work, with a moderate engine compression ratio the achievable engine load range was controlled by the degree of internal trapping of exhaust gas supplemented by inlet charge heating. Increasing the compression ratio decreased the inlet temperature requirements; however, it also resulted in higher pressure rise rates. Varying the inlet valve timing affects the combustion phasing which can help to decrease the maximum pressure rise rates. NOx emissions were characteristically low due to the nature of homogeneous combustion.     

The fuel properties of three-phase emulsions as an alternative fuel for diesel engines

Diesel engines are employed as the major propulsion power for in-land and marine transportation vehicles primarily because of their rigid structure, low breakdown rate, high thermal efficiency and high fuel economy. It is expected that diesel engines will be widely used in the foreseeable future. However, the pollutants emitted from diesel engines (in particular nitrogen oxides and particulate matter) are detrimental to the health of living beings and ecological environment have been recognized as the major air pollution source in metropolitan areas and have thus attracted much research interest. Although diesel oil emulsion has been considered as a possible approach to reduce diesel engine pollutants, previous relevant applications were restricted to two-phase emulsions. Three-phase emulsions such as oil-in-water-in-oil briefly denoted as O/W/O emulsions and water-in-oil-in-water, denoted as W/O/W, have not been used as an alternative fuel for any combustion equipment. Studies on the properties of three-phase emulsion as fuel have not been found in the literatures. The emulsification properties of an O/W/O three-phase diesel fuel emulsion were investigated in this experimental study. The results show that the mean drop size of the O/W/O emulsion was reduced significantly with increasing homogenizing machine revolution speed. An increase in inner phase proportion of the O/W/O emulsion resulted in increasing the emulsion viscosity. The viscosity of O/W/O emulsion is greater than that for water-in-oil (denoted briefly as W/O emulsion) for the same water content. More stable emulsion turbidity appeared for three-phase O/W/O diesel emulsions added with emulsifier with HLB values ranging from 6 to 8. In addition, three-phase O/W/O emulsions with greater water content will form a larger number of liquid droplets, leading to a faster formation rate and greater emulsion turbidity at the beginning but a faster descending rate of emulsion turbidity afterwards. The potential for using O/W/O emulsions as an alternative fuel for diesel engines was also evaluated.     

Modern hydroprocesses for the synthesis of high-quality low-viscous marine fuels

Basic physicochemical and service properties inherent in middle distillate fractions from hydrocatalytic and thermodestructive processes are studied for one Russian refinery from the viewpoint of using them as potential components for low-viscous marine fuels (LMFs) with improved environmental and low-temperature properties. A laboratory-scale flow-through setup loaded with an industrial nickel–molybdenum catalyst is used for the hydrocracking of vacuum gasoils (with T _ebp ranging from 500 to 580°C) at 340–380°C and 15.0 MPa. The highest yield of the light hydrocracking gasoil (LHCG) is observed upon the processing of vacuum gasoil (T _ebp, 350–500°C) at 360°C, the highest cetane index (53 points) and the lowest sulfur content (7 ppm) being characteristic of the obtained LHCG. With heavier vacuum gasoil, the total yields of target distillates and the yield of LHCG decrease. In terms of physicochemical and service properties, the obtained LHGC is a high-quality component of LMFs. Comparative properties of the hydrorefined virgin diesel fraction, light gasoils obtained via catalytic cracking, slow coking, and the promising hydrocracking process are analyzed. The physicochemical, environmental, and main service properties inherent in the middle distillate fractions of secondary processes are determined depending on their hydrocarbon and nonhydrocarbon compositions, and on the content of key components. Based on these dependences, recommendations are made for the production of optimum low-viscous marine fuels with improved environmental and low-temperature properties.     

Effects of particle size on the fast pyrolysis of oil mallee woody biomass

This study aims to investigate the effects of biomass particle size (0.18-5.6 mm) on the yield and composition of bio-oil from the pyrolysis of Australian oil mallee woody biomass in a fluidised-bed reactor at 500 °C. The yield of bio-oil decreased as the average biomass particle size was increased from 0.3 to about 1.5 mm. Further increases in biomass particle size did not result in any further decreases in the bio-oil yield. These results are mainly due to the impact of particle size in the production of lignin-derived compounds. Possible inter-particle interactions between bio-oil vapour and char particles or homogeneous reactions in vapour phases were not responsible for the decreases in the bio-oil yield. The bio-oil samples were characterised with thermogravimetric analysis, UV-fluorescence spectroscopy, Karl-Fischer titration as well as precipitation in cold water. It was found that the yields of light bio-oil fractions increased and those of heavy bio-oil fractions decreased with increasing biomass particle size. The formation of pyrolytic water at low temperatures (<500 °C) is not greatly affected by temperature or particle size. It is believed that decreased heating rates experienced by large particles are a major factor responsible for the lower bio-oil yields from large particles and for the changes in the overall composition of resulting oils. Changes in biomass cell structure during grinding may also influence the yield and composition of bio-oil.     

生物油非催化热转化过程中受热结焦特性研究进展

生物油在受热条件下极易结焦,结焦是影响生物油规模化利用的重要因素之一,因此深入理解生物油受热结焦特性是实现生物油高效热转化利用的基础。本文从生物油热解过程的关键反应参数（温度、升温速率、气氛、压力、灰分）、生物油化学成分、生物油有机组分间交互作用、自由基反应特性等方面综述了生物油受热结焦特性相关研究进展,总结了反应参数对生物油热解结焦反应网络的影响,梳理了生物油各特征组分单独热解结焦及特征组分间交互作用对结焦特性的影响机制,并基于生物油结焦机理和焦炭的物化特性,总结了通过定向调控生物油结焦反应过程,将焦炭作为燃料和炭材料的潜在利用途径。最后,指出了明晰生物油受热结焦机理还需从生物油组分间交互作用机制和自由基反应机理的角度进一步探究。本文为实现生物油高效热转化利用提供了理论参考和借鉴。     

Investigations on surrogate fuels for high-octane oxygenated gasolines

Gasoline is a complex mixture that possesses a quasi-continuous spectrum of hydrocarbon constituents. Surrogate fuels that decrease the chemical and/or physical complexity of gasoline are used to enhance the understanding of fundamental processes involved in internal combustion engines (ICEs). Computational tools are largely used in ICE development and in performance optimization; however, it is not possible to model full gasoline in kinetic studies because the interactions among the chemical constituents are not fully understood and the kinetics of all gasoline components are not known. Modeling full gasoline with computer simulations is also cost prohibitive. Thus, surrogate mixtures are studied to produce improved models that represent fuel combustion in practical devices such as homogeneous charge compression ignition (HCCI) and spark ignition (SI) engines. Simplified mixtures that represent gasoline performance in commercial engines can be used in investigations on the behavior of fuel components, as well as in fuel development studies. In this study, experimental design was used to investigate surrogate fuels. To this end, SI engine dynamometer tests were conducted, and the performance of a high-octane, oxygenated gasoline was reproduced. This study revealed that mixtures of iso-octane, toluene, n-heptane and ethanol could be used as surrogate fuels for oxygenated gasolines. These mixtures can be used to investigate the effect of individual components on fuel properties and commercial engines performance.     

Removal and utilization of organic acids in bio-oil

生物质快速热裂解制取的生物油是燃料和化学品的重要来源。本文介绍了生物油中有机酸的存在形式、形成机理以及生物油中有机酸的去除方法和利用研究进展,分析了各种方法的优缺点以及目前面临的主要问题。总体来说,开发高效稳定的催化剂应用于催化酯化是去除生物油中有机酸以期获得高品质燃油的重点,而将有机酸在生物油中直接转化为高附加值化工品是较为理想的有机酸利用方式。     

介孔碳材料改性研究进展及在生物油加氢反应中的应用综述

综述了介孔碳材料制备的研究进展,对介孔碳改性方面的研究工作进行了着重的推介。并介绍了在介孔碳研究中,不同的改性方法对介孔碳性能的影响,特别介绍了现阶段以介孔碳为载体的制氢/加氢反应性能的研究。最后对介孔碳在生物油加氢改质的潜在应用和发展方向进行了展望。     

生物油制备、性质与应用的研究进展

介绍了国内外生物油的发展现状。根据生物油制备原料不同,将其分为植物油、热裂解油和生物柴油等。概括了生物油制备的方法和原理,分析3种生物油的物理化学性质。综述了生物油的主要应用方式,包括食品加工、化工应用和燃烧应用等。最后总结了生物油领域存在的主要问题,并对生物油应用方面的发展方向进行了展望。     

Fast Pyrolysis of Biomass in a Spout-fluidized Bed Reactor--Analysis of Composition and Combustion Characteristics of Liquid Product from Biomass

In order to gain insight into the fast pyrolysis mechanism of biomass and the relationship between bio-oil composition and pyrolysis reaction conditions, to assess the possibility for the raw bio-oil to be used as fuel, and to evaluate the concept of spout-fluidized bed reactor as the reactor for fast pyrolysis of biomass to prepare fuel oil, the composition and combustion characteristics of bio-oil prepared in a spout-fluidized bed reactor with a designed maximum capacity 5 kg/h of sawdust as feeding material, were investigated by GC-MS and thermogravimetry. 14 aromatic series chemicals were identified. The thermogravimetric analysis indicated that the bio-oil was liable to combustion, the combustion temperature increased with the heating rate, and only minute ash was generated when it burned. The kinetics of the combustion reaction was studied and the kinetic parameters were calculated by both Ozawa-Flynn-Wall and Popsecu methods. The results agree well with each other. The most probable combustion mechanism functions determined by Popescu method are f(a)=k(1-a)2 (400~406℃), f(a)=1/2k(1-a)3 (406~416℃) and f(a)=2k(1-a)3/2 (416~430℃) respectively.