水库蓄水库区浸没影响因素评价

为明确库区浸没影响因素及其在浸没发生过程中的重要性,在系统分析库区浸没成因的基础上,提出了库区浸没影响因素的评价指标体系和方法,以燕山水库为例,对库区浸没影响因素进行评价,确定了该水库库区浸没的主要影响因素,评价结果符合工程实际,指标体系合理可行,评价方法正确有效。     

工业废水中总氮测定的影响因素探讨

工业废水的治理中,总氮是一个非常重要的检测指标.目前水质总氮的检测主要采用碱性过硫酸钾消解紫外分光光度法,该方法在实际应用过程中容易受到多种因素影响,造成水质总氮测定达不到理想的准确度.因此,有必要对该方法测定过程中的影响因素进行分析,从而采取有效的措施来消除这些因素的影响,提高该方法应用于工业废水总氮指标检测的可靠性.     

一种自动检测发电机组高低压加热器水位报警根源的方法

文中详细介绍影响回热加热器水位的各个因素,并提取水位发生报警之后进行根源检测所需的数据段;根据各个影响因素与水位在当前数据段中的趋势获取报警根源;通过三个工业实例提出并验证了一种自动检测报警根源的方法,该方法通过获取水位报警之前的异常过程段,分析在该过程段中,各个影响因素与水位之间的相关性趋势,自动判断引起报警的因素,自动检测引起水位报警的根源因素。在报警发生之后,该方法有助于运行人员快速获取报警根源,采取相应措施缩短报警时间,减小机组经济损失,保证机组安全运行。     

生物质挤压过程中的静水压应力

将生物质压缩成型是一个相当复杂的过程,该过程除了受压力、温度的影响之外。还受多种其他因素的影响。利用ANSYS软件对挤压过程进行有限元模拟,分析了静水压应力对材料致密过程的作用,为生物质成型机理的研究提供了可靠依据。     

热轧吨钢电耗预测模型建立及应用

本文基于热轧生产过程原始数据,对影响热轧吨钢电耗的影响因素利用Minitab软件中回归工具进行了相关分析,确定了影响热轧吨钢电耗的主要因素,并建立了吨钢电耗的多元线性回归模型,通过与重新选取的原始数据建立的模型进行对比,证明该预测模型具有较高的预报精度。     

加压脱除富氧燃烧过程中产生的NOx机理研究

分两步除去富氧燃烧过程所产生污染物NOx的方法被提出:首先将NO氧化为NO2,其次利用液态水吸收NO2.利用CHEMKIN软件,通过ROP分析法和参数分析法确定了氧化NO的主要过程和影响因素.结果指出,增压燃烧和添加臭氧可促进NO向NO2的转化,压力大小、反应时间和温度是影响该转化过程的主要因素.     

基于Fuzzy-DEMATEL的水电项目隐性成本影响因素分析

为加强水电项目实施过程中隐性成本的管理,构建隐性成本影响因素指标体系,引入三角模糊数理论,建立了基于Fuzzy-DEMATEL的水电项目隐性成本影响因素评价模型,并结合实例计算各影响因素的中心度和原因度,挖掘因素间的相互关系,识别影响隐性成本的主要因素。结果表明,人员组织、管理体制、运行机制、施工组织、物资保障、变更索赔和自然条件是主要因素,管理因素和技术因素是控制的重点对象。该方法合理可行,为隐性成本管理工作提供了参考。     

旋风分离器性能仿真模型及其应用

从分析固相颗粒在旋风分离器中的运动轨迹和浓度分布情况入手 ,建立了旋风分离器性能分析模型。该模型在一定程度上突破了“径向混合”的假设 ,并充分考虑了重力沉降和径向加速过程对固相分离的影响 ,进一步加强了理论模型对实际过程的描述能力。通过工业性试验结果证明了模型的有效性 ,并利用该模型对 1台细粉分离器的工作性能进行了数值仿真研究 ,重点讨论了分离器的工作参数及结构特性等因素对分离效果的影响     

模糊相似优先比在钢铁企业中的应用

通过对钢铁企业主工序分厂煤气发生机理和消耗特性研究,找到影响各分厂煤气发生量和消耗量的主要因素,进而对煤气发生量和煤气消耗量进行预测,以便确定合理的煤气使用方案。在研究煤气发生量与消耗量影响因素的过程中,采用一种新的数学方法即模糊相似优先比法进行分析,并用灰色关联度法进行验证,两种方法的分析结果完全一致,充分肯定了该方法的可行性,建议推广该方法在钢铁企业理论分析中的应用。     

相变围护结构热性能评价方法和影响因素研究

为了揭示相变围护结构内、外表面的传热机理,文章针对夏季相变围护结构的两种不同传热过程,提出了"隔热因子"和"吸热因子"两个评价指标用于评价其传热性能,并利用热阻法建立了两种传热情况下的传热方程,对两个评价指标进行了理论求解;最后对影响两个评价指标的各个因素进行了单因素分析,得出不同因素对评价指标影响的规律。该研究可以为相变围护结构的参数选择提供理论依据和技术支持。     

百吨级生物质合成气合成二甲醚中试系统设计及运行分析

该系统以农业废弃物玉米芯经富氧气化制备的低H_2/CO合成气为气源,采用固定床一步法合成二甲醚工艺,高效生产DME产品.运行结果表明,在空速为650h~(-1)和1200h~(-1)时,CO单程转化率分别为82.00%和73.55%.DME选择性分别为73.95%和69.73%,DME时空产率分别为124.28kg/(m~3·h)和203.80kg,(m~3·h).生物质合成气的深度脱氧和脱焦油是保证合成系统稳定运行的关键.合成尾气H_2/CO较高,经脱CO_2后循环利用可大大提高DME的产率.     

秸秆燃气合成甲醇的优化试验研究

以秸秆合成气为原料,在直流流动等温积分反应器中,使用国产C301铜基催化剂,在5 MPa压力下,进行催化合成甲醇的反应温度、秸秆合成气配比、合成气进口流量的优化试验研究.试验获得了玉米秸秆合成气合成甲醇的最佳反应条件,为生物质（秸秆）气制甲醇中试研究提供科学和实用的参考依据.     

High quality H2-rich syngas production from pyrolysis-gasification of biomass and plastic wastes by Ni–Fe@Nanofibers/Porous carbon catalyst

To produce the high quality H₂-rich syngas from biomass and plastic wastes, a two-stage pyrolysis-gasification system involving pyrolysis and catalytic gasification is considered as a suitable route. Generally, synthesis of highly active, low cost and coke-resistant catalyst for tar cracking is the key factor. A series of monometallic catalysts of Ni@CNF/PCs and Fe@CNF/PCs and the bimetallic Ni–Fe@CNF/PCs catalyst were prepared by a simple one-step pyrolysis approach for high quality syngas production from pyrolysis-gasification of biomass and plastic wastes. The results indicated that the bimetallic Ni–Fe@CNF/PCs catalyst appeared as the optimal catalyst in affording the best compromise between catalytic activity and stability with the existence of the excellent dispersibility of the Fe0.64Ni0.36 alloy nanoparticles and the carbon nanofibers/porous carbon composite structure. In addition, the optimal operation conditions of biomass/plastic ratio of 1/2 and gasification temperature of 700 °C were observed for the bimetallic Ni–Fe@CNF/PCs catalyst to play best roles in the H₂-rich syngas quality, with up to 33.66 mmol H₂/g biomass, and tar yields as low as 5.66 mg/g.     

Experimental and numerical study of syngas production during premixed and ultra-rich partial oxidation of methane in a porous reactor

The synthesis gas (syngas) production from the ultra-rich methane/oxygen mixtures via the thermal partial oxidation in an inert porous reactor was investigated numerically and experimentally. Thermodynamic analysis was firstly conducted based on Gibbs free energy minimization method to find the possible optimum routes of operation. Then, the experiments were performed on the constructed test-rig with a non-catalytic porous based reformer. The flame is stabilized within zirconia (ZrO₂) sponge, which has shown very high mechanical strength and thermal resistance. The main influencing parameters such as the equivalence ratio and thermal load have been investigated during different experiments. For this purpose, the reactor axial temperature profile and product compositions were determined experimentally. The obtained results reveal that the heat loss abatement; approaching to the adiabatic condition could effectively improve the amounts of syngas (H₂+CO) production. The maximum syngas production was obtained 69.5% of the exhaust gas at the equivalence ratio of 2.5 and thermal load of 8 kW. Moreover, the H₂/CO ratio was reported above 1.5, which can be suitable for feeding into other chemical processes. Finally, numerical simulation of the process was performed using the premixed and reactor network models. The contribution of heat loss from the reactor was also considered in the model due to its pivotal role observed in the experimental work. The average relative error of the reactor network model with respect to syngas generated from the reformer was found to be 6.72%. Therefore, the predictions obtained from this model are in fairly good agreement with the experimental data.     

甲醇合成气的制取与等压合成创新工艺的发展前景

介绍了甲醇合成工艺的进展，指出现代工业生产采用压力为5MPa的高压造气等压合成甲醇工艺，分析了合成气对甲醇合成的影响。重点阐述了轻烃转化制甲醇合成气的创新工艺——三一段（即外热蒸汽转化、换热转化和自热转化）纯氧转化工艺的特点、原理、工艺流程及主要物耗能耗指标，并与传统工艺进行了对比。举例说明了高压合成气等压合成甲醇技术的推广应用。最后对我国煤炭能源化工综合发展的产品开发和规划框架提出了建议。     

Syngas production from CO2 reforming of methane over Ni supported on hierarchical silicalite-1 fabricated by microwave-assisted hydrothermal synthesis

The conversion of carbon dioxide and methane to syngas is one of the most environmentally benign routes for methane reforming, where the two major greenhouse gases are converted to hydrogen or syngas (H₂ and CO). Hierarchical silicalite-1 was prepared in one-step by the microwave-assisted hydrothermal synthesis (MAHyS) approach. Ni particles with loadings of 5, 10, 15 and 20 wt.% were impregnated on the silicalite-1, as well as modified silicalite-1. The mesopore volume of the 20 wt.% Ni on S-1 catalyst increased from 0.0712 cm³/g to 0.1159 cm³/g by ion-exchanging silicalite-1 with Ce, prior to impregnation. The structural integrity of the modified catalysts was maintained as shown by characterization with XRD, FESEM, N₂-physisorption, XPS and FTIR. Reducibility studies by H₂-TPR showed that the addition of a second metal enhanced Ni reducibility. The 20 wt.% Ni on silicalite-1 was found to be more active than 10 and 15 wt.% on silicalite-1. Upon modification before impregnation of the 20 wt.% Ni, it was observed that Ce-ion-exchanged silicalite-1 supported Ni catalyst was the most active catalyst during 12 h time-on-stream (TOS). Raman spectroscopy and TGA-DSC revealed that the carbon deposits on the surfaces of the spent catalysts were predominantly crystalline.     

System study on natural gas-based polygeneration system of DME and electricity

An innovative system for the polygeneration of dimethyl ether (DME) and electricity was proposed in this paper. The system uses natural gas as the raw material. Polygeneration is sequential, with one-step and once-through DME synthesis. Syngas is made to react to synthesize DME first, and then the residual syngas is sent to the power generation unit as fuel. The exergy analysis from the view of cascade utilization was executed for individual generation and for polygeneration. The analysis results showed that both chemical energy and thermal energy in polygeneration were effectively utilized, and both chemical exergy destruction and thermal exergy destruction in polygeneration were decreased. The cause of the decrease in exergy destruction was revealed. The analysis showed that hydrogen-rich (natural gas-based) polygeneration was as desirable as carbon-rich (coal-based) polygeneration. The energy saving ratio of polygeneration was about 10.2%, which demonstrated that high efficiency natural gas-based polygeneration is attainable, and the cascade utilizations of both chemical energy and thermal energy are key contributors to the improvement of performance. Copyright © 2007 John Wiley & Sons, Ltd.     

Enhancement of the quality of syngas from catalytic steam gasification of biomass by the addition of methane/model biogas

In this study, methane and model biogas were added during the catalytic steam gasification of pine to regulate the syngas composition and improve the quality of syngas. The effects of Ni/γ-Al₂O₃ catalyst, steam and methane/model biogas on H₂/CO ratio, syngas yield, carbon conversion rate and tar yield were explored. The results indicated that the addition of methane/model biogas during biomass steam gasification could increase the H₂/CO ratio to about 2. Methane/model biogas, steam and Ni/γ-Al₂O₃ catalyst significantly affected the quality of syngas. High H₂ content syngas with H₂/CO ratio of about 2, biomass carbon conversion >85% and low tar yield was achieved under the optimum condition: S/C = 1.5, α = 0.2 and using Ni/γ-Al₂O₃ catalyst. According to ANOVA, methane and catalyst were the key influencing factors of the H₂/CO ratio and syngas yield, and the tar yield mainly depended on the Ni/γ-Al₂O₃ catalyst. Biogas, as a more environmentally friendly material than methane, can also regulate the composition of syngas co-feeding with biomass.     

Operation window and part-load performance study of a syngas fired gas turbine

Integrated coal gasification combined cycle (IGCC) provides a great opportunity for clean utilization of coal while maintaining the advantage of high energy efficiency brought by gas turbines. A challenging problem arising from the integration of an existing gas turbine to an IGCC system is the performance change of the gas turbine due to the shift of fuel from natural gas to synthesis gas, or syngas, mainly consisting of carbon monoxide and hydrogen. Besides the change of base-load performance, which has been extensively studied, the change of part-load performance is also of great significance for the operation of a gas turbine and an IGCC plant.In this paper, a detailed mathematical model of a syngas fired gas turbine is developed to study its part-load performance. A baseline is firstly established using the part-load performance of a natural gas fired gas turbine, then the part-load performance of the gas turbine running with different compositions of syngas is investigated and compared with the baseline. Particularly, the impacts of the variable inlet guide vane, the degree of fuel dilution, and the degree of air bleed are investigated. Results indicate that insufficient cooling of turbine blades and a reduced compressor surge margin are the major factors that constrain the part-load performance of a syngas fired gas turbine. Results also show that air bleed from the compressor can greatly improve the working condition of a syngas fired gas turbine, especially for those fired with low lower heating value syngas. The regulating strategy of a syngas fired gas turbine should also be adjusted in accordance to the changes of part-load performance, and a reduced scope of constant TAT (turbine exhaust temperature) control mode is required.     

Production of hydrogen rich bio-oil derived syngas from co-gasification of bio-oil and waste engine oil as feedstock for lower alcohols synthesis in two-stage bed reactor

High efficient production of lower alcohols (C₁–C₅ mixed alcohols) from hydrogen rich bio-oil derived syngas was achieved in this work. A non-catalytic partial oxidation (NPOX) gasification technology was successfully applied in the production and conditioning of bio-oil derived syngas using bio-oil (BO) and emulsifying waste engine oil (EWEO) as feedstock. The effects of water addition and feedstock composition on the gasification performances were investigated. When the BO₂₀ and EWEO₃₀ was mixed with mass ratio of 1: 0.33, the maximum hydrogen yield of 93.7% with carbon conversion of 96.7% was obtained, and the hydrogen rich bio-oil derived syngas was effectively produced. Furthermore, a two-stage bed reactor was applied in the downstream process of lower alcohols synthesis from hydrogen rich bio-oil derived syngas (H₂/CO/CO₂/CH₄/N₂ = 52.2/19.5/3.0/9.4/15.9, v/v). The highest carbon conversion of 42.5% and the maximum alcohol yield of 0.18 kg/kg_cat h with selectivity of 53.8 wt% were obtained over the Cu/ZnO/Al₂O₃(2.5)//Cu₂₅Fe₂₂Co₃K₃/SiO₂(2.5) catalyst combination system. The mechanism and evaluation for lower alcohols synthesis from model bio-oil derived syngas and model mixture gas were also discussed. The integrative process of hydrogen rich bio-oil derived syngas production and downstream lower alcohols synthesis, potentially providing a promising route for the conversion of organic wastes into high performance fuels and high value-added chemicals.