Computational particle fluid dynamics (CPFD) approach is used to simulate a horizontal tube with an extra air intake. To determine the optimal values for the two objectives, a one-factor hill-climbing test is performed on three structural parameters of the auxiliary air intake (intake velocity, intake angle, and distance between two neighboring valves) and two objective values (operating time and power consumption coefficient). In this paper, a multi-objective optimization of the three structural parameters has been carried out using the response surface methodology and designing a multi-group central test. It was discovered that when the main air intake speed was 3 m/s, adding an auxiliary air intake with an intake speed of 5 m/s, an intake angle of 45 degrees, and a distance of 1900 mm between the two adjoining valves improved particle evacuation. When compared to the situation with a main air intake speed of 5 m/s and no auxiliary air intake, the working time is reduced by 4.97%, and the power consumption coefficient is reduced by 33.51%. (c) 2025 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Purpose Diesel has traditionally been considered the best-suited and most widely used fuel in various sectors, including manufacturing industries, power production, automobiles and transportation. However, with the ongoing crisis of fossil fuel inadequacy, the search for alternative fuels and their application in these sectors has become increasingly important. One particularly interesting and beneficial alternative fuel is biodiesel derived from bio sources. Design/methodology/approach In this research, an attempt was made to use biodiesel in an unconventional micro gas turbine engine. It will remove the concentric use of diesel engines for power production by improving fuel efficiency as well as increasing the power production rate. Before the fuel is used enormously, it has to be checked in many ways such as performance, emission and combustion analysis experimentally. Findings In this paper, a detailed experimental study was made for the use of Spirulina microalgae biodiesel in a micro gas turbine. A small-scale setup with the primary micro gas turbine and secondary instruments such as a data acquisition system and AVL gas analyser. The reason for selecting the third-generation microalgae is due to its high lipid and biodiesel production rate. For the conduction of experimental tests, certain conditions were followed in addition that the engine rotating rpm was varied from 4,000, 5,000 and 6,000 rpm. The favourable and predicted results were obtained with the use of microalgae biodiesel. Originality/value The performance and combustion results were not exactly equal or greater for biodiesel blends but close to the values of pure diesel; however, the reduction in the emission of CO was at the appreciable level for the used spirulina microalgae biodiesel. The emission of nitrogen oxides and carbon dioxide was a little higher than the use of pure diesel. This experimental analysis results proved that the use of spirulina microalgae biodiesel is both economical and effective replacement for fossil fuel.

Amine-modified mesoporous silicon was widely used for CO2 capture. However, its adsorption capability was significantly affected by temperature and humidity. In this paper, tetraethylenepentamine (TEPA) modified SBA15 adsorbents were prepared for capturing CO2. The effects of the modification method, the concentration of TEPA, the adsorption temperature, and the humidity of atmosphere on CO2 adsorption capability were studied. Moreover, combined with molecular dynamics (MD) and density functional theory (DFT) computations, the diffusion characteristics and adsorption mechanism were explored. The CO2 adsorption capability of the adsorbent prepared by the ultrasonic impregnation method was higher than those prepared by the stirring impregnation method, owing to that ultrasonic impregnation could promote the uniformity of TEPA. With the increase of TEPA concentration of SBA-15, the CO2 adsorption capability increased. SBA-15-2 had the highest CO2 adsorption capability of 1.17 mmol/g at 30 degrees C. This was due to the N-containing functional groups, showing good affinity for CO2, introduced by TEPA impregnation. When the temperature increased from 30 degrees C to 70 degrees C, the CO2 adsorption capability of all modified SBA-15 adsorbents decreased, since the CO2 adsorption was an exothermic reaction. SBA-15-2 showed better water vapor resistance than SBA-15-2 (Stir). This was related to the higher dispersity of organic carbon chain introduced by TEPA modification after ultrasonic impregnation. The organic carbon chain of SBA-15-2 increased the water vapor resistance by reducing the hydroxyl group. Finally, from a microscopic aspect, the MD simulation suggested that impregnated TEPA inside SBA-15 may improve CO2 capture by increasing the thickness of effective adsorption layer. Besides, the DFT simulation showed that TEPA modification increased the adsorption energy of SBA-15 on CO2. This serves as a reference for later mesoporous silicon adsorbent research and development on CO2 capture.

Numerical simulations for the air-solid two-phase flow in a horizontal pipe with a diameter of 125 mm and a length of 10 m were carried out using the Computational Particle Fluid Dynamics (CPFD) method. The deposition characteristics of particles in the pipe were investigated at various inlet flow rates and velocities, and the effect of the auxiliary inlet with different structural parameters on the evacuation of particles in the pipe after the auxiliary inlet was added to the horizontal pipe was compared. The results show that when the volume fraction of particles in the tube is less than 0.6, the flow of particles is relatively stable, and when the volume fraction of particles is greater than 0.8, the particles are seriously deposited and easily form a blockage; the auxiliary air inlet speed is proportional to the effect at the same tilt angle; when the air inlet speed is constant, the auxiliary air inlet angle increases from 35 degrees to 55 degrees, the effect of auxiliary air inlet increases and then decreases, and the effect of auxiliary air inlet reaches its peak at around 45 degrees. The study's findings have implications for long-distance particle transport in horizontal pipelines.

Adding CaO during the combustion of oil shale (OS) reduces sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions, but it is challenging to synergistically control SO2 and NOx during fluidized combustion. This study utilized a lab-scale fluidized-bed reactor to explore the transformations of nitrogen and sulfur during the combustion of Chinese Beipiao oil shale (BOS) under different temperatures and Ca/S molar ratios. CaO significantly changed the combustion characteristics of OS by slowing the combustion rate of organic matter and altering the transformation mechanisms of nitrogen and sulfur. As the combustion temperature increased, the NO emissions initially rose and then decreased, while SO2 showed the opposite trend. The addition of CaO promoted the conversion of NH3 and HCN into NO and facilitated the reduction of NO to N2 through reactions with CO and char, which helped control NOx. Moreover, when the Ca/S molar ratio was 4.53, CaO reacted with released SO2 to form CaSO4, which significantly increased the sulfur fixation rate to 90.82 %. This research provides guidance for optimizing large-scale clean combustion technologies for OS and reducing pollutant emissions.

To address the leakage and low thermal conductivity issues of phase change materials (PCMs), this study aims to prepare high thermal conductivity shape stable composite phase change materials (sscPCMs) using waste peanut shell. Employing pyrolysis technology, waste peanut shell has been successfully converted into high-performance framework materials. In addition, it also compared the thermal energy storage performance of shape stable composite stearic acid/peanut shell biochar (ss-cSA/PSC) with that of shape stable composite stearic acid/peanut shell (ss-cSA/PS). Excitingly, the thermal energy storage performance of ss-cSA/PSC has been significantly improved. Specifically, the thermal conductivity of ss-cSA/PSC reached 0.527 W/(m & sdot;K), which is 3.2 times higher than that of pure SA and 2.4 times higher than that of ss-cSA/PS. In addition, the phase change latent heat of ss-cSA/PSC can reach 70.59 J/g, which is 27.2% higher than that of ss-cSA/PS. The high thermal conductivity and phase change latent heat highlighted its significant superiority in the field of thermal energy storage. Furthermore, ss-cSA/PS and ss-cSA/PSC have been characterized by SEM, FTIR, XRD, and TGA. The results indicated that both two kinds of sscPCMs have excellent chemical compatibility, thermal reliability, and thermal stability. In summary, PSC is an economical, environmentally friendly, and sustainable framework material which used to prevent the leakage of PCMs and improve the thermal performance.

Agroforestry Waste (AW) is seen as a carbon neutral resource. However, the poor quality of AW reduced its potential application value. Even more unfortunately, chlorine in AW led to the formation of organic pollutants such as dioxins under higher temperatures. Alkali and alkaline earth metals (AAEMs) in ash may deepen the reaction degree. Co-pretreatment of dry torrefaction and de-ashing followed by thermochemical conversion is a promising technology, which can improve raw material quality, inhibit the release of organic pollutants and transform AW into eco-friendly energy carriers. In order to better understand the process, theoretical basis such as the structural characteristics, thermal properties and separation methods of structural components of AW are described in detail. In addition, dry torrefaction related reactors, process parameters, kinetic analysis models as well as the evaluation methods of torrefaction degree and environmental impact are systematically reviewed. The problem of ash accumulation caused by dry torrefaction can be well solved by de-ashing pretreatment. This paper provides a comprehensive discussion on the role of the two- and three-stage conversion technologies around dry torrefacion, de-ashing pretreatment and thermochemical conversion in products quality enhancement. Finally, the existing technical challenges, including suppression of gaseous pollutant release, harmless treatment and reuse of torrefaction liquid product (TPL) and reduction of torrefaction operating costs, are summarized and evaluated. The future research directions, such as vitrification of the reused TPL (after de-ashing or acid catalysis) and integration of oxidative torrefaction with thermochemical conversion technologies, are proposed.

The motion of binary particles in three horizontal rotating drums with continuous rotational speed changes was studied based on the Discrete Element Method (DEM). Different simulation conditions were compared between two circular drums and an elliptical drum using the same number of physical properties for binary particles and drums, rotating at a speed series from 0.01 to 21.9 rad/s. By varying the rotational speed, four flow regimes were produced in the simulation. Flow regimes, velocity vectors, normal forces, and the number of contacts between 1 mm particles and 3 mm particles were comparatively analyzed, especially the particle velocity at transient changing rotational speeds. The results showed that four flow regimes were found at the same rotational speed for three different rotating drums, and normal forces were weakest for the cataracting regime; moreover, the three layers of particles were damaged when the rotational speed was suddenly decreased and the velocity direction of the particle motion was changed at the top of the particles’ bed. The maximum number of contacts was found with the rolling regime, based on the simulation results. The number of contacts of the major axis circular drum was smaller than for the minor axis at the same rotational speed, and the number of contacts of the elliptical drum was the largest among the three rotating drums.

Baffles can effectively improve the mixing and heat transfer in internally heated rotating drums. To explore the performance of baffles, discrete element method (DEM) is employed in this work, and the influence of the placement and length of baffles on the mixing and heat transfer in an internally heated drum is investigated. The simulation results show that a central cross baffle promotes the mixing and heat transfer significantly, and the optimal length varies with material properties, for example, at the length-to-diameter ratio L/D = 0.4 for monodispersed glass particles, 0.6–0.7 for binary glass-steel mixtures. The peripheral baffle generally weakens the mixing and heat transfer performance, and effects only for a sufficiently long peripheral baffle at the length-to-radius ratio L/R = 0.9. Baffles promote the heat transfer process and do not change the thermal contribution of heat transfer paths.

In this work, for an ultra-supercritical tangentially fired boiler, the mixed burning characteristics of Zhundong coal and Beitashan coal under 600 MW were studied using numerical simulations. By adjusting operating parameters, the phenomenon of wall brushing on the cross-section of D burner was improved. Moreover, the high-temperature corrosion, coking and NOx generation characteristics, and the correlation in the water wall area of the boiler were analyzed. The optimal operation mode was also explored to improve the mixed burning ratio of Zhundong coal until purely-burning. Lower burnout air rate (17.6%) under different mixed burning conditions minimized the coking risk and the degree of burnout of the boiler. At the same time, when the mixed burning ratio was 10:0, the burnout air rate was within the range of 17.6- 22.6%, 27.6- 30%, whereas the average value of NOx at the furnace outlet decreased significantly. When the burnout air rate was within the range of 22.6- 27.6% under two mixed burning ratios, there was no significant difference in the air-staged degree of combustion in the primary combustion zone. Meanwhile, the NOx emissions did not change significantly. The research results can provide a reference for similar furnaces purely-burning Zhundong coal.

Mixing and heat transfer among particles in rotating drums are widely applied in numerous industrial processes. Generally, mixing and heat transfer occur simultaneously. Consequently, the interrelationship between mixing and heat transfer must be investigated for industrial applications. In this study, the radial mixing and heat transfer of spherical granular materials (3 mm) with various properties in batch rotating drums are investigated numerically using the discrete element method. The evolution of mixing and heat transfer characteristics with rotation speed is analyzed from the perspective of time and number of revolutions, respectively. The results indicate that, depending on the physical parameters and thermal properties of particles, the mixing quality does not always accurately reflect the heat transfer effect. In binary granular beds of monodispersed spherical particles with different densities and thermal diffusivities, the main heat transfer mechanism is related to the ratio of the thermal conductivity of the particles to that of the fluid.

The non-structural components (extractives and ash) in biomass can affect the torrefaction characteristics. The objective of this study was to investigate the applicability of air oxidative and non-oxidative torrefaction for corn stalk, which has higher organic extractives and lower ash contents. The raw materials were torrefied with air and nitrogen in a fluidized bed reactor at 180?C-235?C and 200?C-280?C for 1 h, respectively. The proximate and ultimate analysis results demonstrated that the lower ash content (3.89%) was not favorable for deoxygenation. The organic extractives, extracted materials and mixture were torrefied with nitrogen at 260?C. The results indicated that the addition of organic extractives reduced the deoxidation efficiency of structural components during torrefaction. Compared to raw materials, the moderate and severe removal of hemicellulose can be achieved through torrefaction under air and nitrogen, respectively.

主要研究了固定床内油页岩干馏过程的三维数值模拟.通过对固定床内气固相间传热传质过程的分析,建立了完整的气固两相传热传质模型,并采用多孔介质模型与流动模型相结合,将干馏过程中水分析出和干馏油气的析出过程通过用户自定义接口添加到模拟过程中.针对实际工况进行了模拟研究并与实验结果进行比对,吻合程度较好.此外,分别从进气速度和进气温度等方面进行对比分析,研究结果表明当进气速度提高0.5倍时,干馏进程加快1600 s.当进气速度降低0.5倍时,干馏进程延缓4200 s,换热效率明显降低.进气温度提高100℃,干馏进程加快600 s,油页岩中干酪根热解过程前期水分最大蒸发速率提高约11.4％.当进气温度降低100℃时,干馏进程延缓1300 s,干酪根热解过程前期水分最大蒸发速率降低约24.7％.在气体热载体和传质过程的共同作用下,靠近进气位置的底部颗粒与周围环境气体中水蒸气及干馏油气之间的浓度梯度小于上部颗粒,这也是固定床内上部颗粒干馏进程较慢的一个重要原因.

The combustion experiment of Longkou oil shale semicoke was conducted in a batch fluidized bed reactor. A specific surface area (SSA) analyzer and a scanning electron microscope (SEM) were used to respectively measure the specific surface area of samples and examine their surface pore structure in different experimental operating conditions, and the fractal dimension (FD) was used to describe the complexity of pore morphology. The results showed that Longkou oil shale semicoke had a developed pore structure, and in the combustion process, its SSA and pore volume first increased and then decreased, remaining finally unchanging. Most pores were micropores and mesopores of about 2 nm in size. The pore structure was fully developed at a temperature of 600 °C, at which the specific surface area and pore volume also reached maximum values. There were great differences in the pore size distribution of semicoke with different particle sizes. As calculated by the box-counting method (BCM) and the Frenkel-Halsey-Hill (FHH) equation, the pore size showed similar trends of variation, increasing first and then decreasing slowly.

为了对富氧低NOx稳燃技术的实际应用效果进行工程示范,针对富氧低NOx稳燃技术在300 MW亚临界煤粉锅炉上的低负荷稳燃特性进行了实炉试验研究.通过将锅炉A、D层原12台一次风燃烧器改造为富氧低NOx燃烧器以及对锅炉主要运行参数的测量分析,研究富氧低NOx稳燃技术对SCR入口的NOx原始排放浓度、烟气温度,以及对锅炉总体运行特性的影响.实炉试验、日常运行以及第三方完成的性能测试结果表明,原锅炉改造应用富氧低NOx稳燃技术后,NOx原始生成量明显降低.改造后的运行实践证明,锅炉最低可在23.5％负荷(70.4 MW)下稳定运行,且同时能保证锅炉出口过热蒸汽参数和再热蒸汽参数达到运行要求、SCR入口烟温维持在280℃以上及NOx原始生成浓度低于300 mg/Nm3,实现NOx超低排放.锅炉运行经济性统计分析表明,采用富燃低NOx稳燃技术后,调峰能力大幅提高,可长期低负荷运行,且可有效投入SCR脱硝系统,锅炉的年平均点火和低负荷稳燃用油量减少了65％.因此富氧低NOx稳燃技术可实现锅炉的低负荷稳燃及超低排放,且大幅降低锅炉点火及稳燃用油,提高锅炉的经济性.

对一台1 t/d油页岩气体热载体干馏炉炉内流场特性进行了数值模拟.基于计算流体力学的理论方法,采用以Erg-un方程基础上建立的多孔介质模型、湍流模型进行研究.将模拟结果与前人研究成果进行对比分析,结果表明,采用添加阻力源项的多孔介质模型、RNG k-ε湍流模型等封闭模型能够较好的模拟炉内流场分布特性,并在原有结构基础上进行优化,增设同轴及偏心轴撞击流布气方式.在本文提出的布气方式下,无论采用同轴亦或是偏心轴布置,均能形成良好的速度场及压力场,提高干馏段气体混合程度,拓宽布气范围,增加气体与固体颗粒之间的接触面积和时间,强化换热进而确保干馏效果.模拟结果可为开发大容量气体热载体干馏炉及优化设计提供理论依据.

Biomass tar is the bottleneck of biomass gasification, which not only is adverse to energy production but also brings severe environmental issues. A scrubber with vegetable oil is considered as a low-cost but efficient approach for tar removal, but the effects of oil’s properties on different tar absorptions were rarely reported. In this study, canola oil, palm oil, and pure oleic acid and linoleic acid, which are the main compounds of vegetable oils, were employed for absorptive removal of benzene, toluene, and phenol. The degree of unsaturation, average molecular weight, and average chain length of solvents were quantitatively characterized. A series of time and temperature-dependent absorption experiments were conducted, and the relationship between oils’ properties and absorption performances was built. Results showed that pure oleic acid had the biggest absorption capacity for benzene and toluene due to the mono-unsaturated structure. Increasing the average molecular weight and chain length also enhanced tar absorption. Moreover, Grey relative analysis was employed to investigate the influence of each factor on tar absorption. The average molecular weight exerted the most significant influence on tar absorption in the tested temperature range whose comprehensive relevance coefficients reached the highest at 0.9810, 0.7669, and 0.7739 for benzene, toluene, and phenol, respectively. This study puts more attention on the nature of vegetable oils, and we hope to provide useful information for modulating a better oil-based scrubber medium and further enhancing tar absorptive removal.

以异丙醇为相转移剂构建了3种可以实现模拟燃油原位氧化脱硫的反应体系,通过改变体系中试剂的体积比,确定最佳的反应体系为异丙醇-乙腈反应体系且体积比为1∶1.在最佳反应体系下,利用单因素法分别考察了Pt/C质量、助剂种类、模拟燃油初始硫质量分数以及有机硫化物的种类对脱硫效果的影响,并进行了新构建的燃油脱硫反应体系的动力学分析.结果 表明,3种反应体系的模拟燃油脱硫率从高到低依次为:异丙醇-乙腈＞异丙醇-DMF＞异丙醇-去离子水,且最佳配比为1∶1;在0.15 g Pt/C催化剂的作用下,模拟燃料油的脱硫效果最好.KOH在4种酸碱添加剂中脱硫效果最好,初始硫质量分数对脱硫效果影响很小;在相同的反应条件下,去除不同硫化物的效果是:DBT＞4,6-DMDBT＞BT.

系统总结了中原油田近十年来研究和实践形成的CO2驱提高采收率技术系列,包括CO2驱油机理、适宜性筛选评价技术、油藏工程技术和配套注采工程技术;评价分析了濮城沙一段下亚段油藏、胡96块等试验区的实施效果,总结不同类型油藏实施CO2驱的得失.研究结果表明,对于特高含水油藏,CO2溶于油斑和油膜,可驱动水驱残余油;对于深层低渗透油藏,CO2与原油界面张力小,毛管阻力小,可以驱替半径为0.01μm以上孔喉中原油.现场实践证实,CO2驱在防腐、剖面监测、分层注入及流度控制等方面已经形成了较成熟的技术,在深层低渗透油藏、特高含水油藏的应用中均取得了较好效果.同时,CO2驱具有不受温度、矿化度影响的优势,在高温高盐油藏具有巨大推广价值,为其他类型油藏注气提高采收率技术和实践提供借鉴.