化工参数动态估计

本文简要介绍了化工参数动态估计中常用的五种数学处理方法,即积分法、微分法、正规状态法、时间常数法和矩匹配法,并结合实例进行了分析讨论。

MDEA脱硫装置化工参数的微机控制

介绍用 TP-801B 8位单板计算机、8位模数转换,电动Ⅲ型仪表组成的直接数字控制系统及其对温度、压力、流量、液位等5个化工参数的集中定值控制方案和方法。并给出了离散型 PID 数字调节的典型算式,导出了适合计算机运算处理的增量形式,介绍了多路控制编程的安排和多路循环的方式。最后还指出了单板计算机控制在经济上费用低廉的优越性,还给出了5个参数实际控制的部分记录曲线。

积木式二维零件图参数化工具系统

积木式二维零件图参数化工具系统清华大学精密仪器与机械学系张林煊，童秉枢，田凌如何迅速形成合乎要求的零件图，对于国内许多普通制造企业来说是ＣＡＤ技术应用中的一个重要课题。参数化绘图是解决这个问题的有效手段，它能够以一个基本零件图为样板，生成一系列不同尺...

超临界锅炉产品参数化工时定额计算研究与系统实现

针对超临界锅炉产品工时定额管理中存在的编制效率低、信息不能及时共享等问题,结合企业工时定额计算的特点,提出了工时定额参数化计算方法,并通过提炼具有超临界锅炉产品特点的工艺知识库,建立了工时定额计算公式;在此基础上,设计并开发了具有通用性、知识性、集成性特点的参数化工时定额计算系统。通过系统实施与应用,提高了临界锅炉产品工时制定的精确性和工艺编制的效率,为产品成本核算、生产计划安排提供了可靠的依据和保证。

卓越工程师教育培养计划下的《化工仪表及自动化》课程内容的教与改

从对化工技术人员在仪表选择、安装、调试、化工参数监测和自动控制的技能要求出发,对《化工仪表及自动化》课程的教学目标、讲授内容及学习效果的考核等方面做了有益的尝试和改革。同时,介绍"卓越工程师教育培养计划"规划教材《化工过程参数监测与自动化》和研发的化工仪表自动化综合实训平台,为本课程的教学提供了很好的借鉴。

既有建筑屋面光伏阵列多目标优化设计研究

基于节能减排背景和双碳目标,既有建筑绿色改造是一项迫切需求。屋面增设光伏阵列是既有建筑节能改造的一项有利途径,但目前常用的基于地域最佳倾角的固定式光伏板铺设方法存在不美观、经济效益低等问题。如何借助数字化技术优化和确定固定式光伏板的倾角,从而收获良好的经济和环境效益,成为人们关注的热点问题。选择四川省成都市一处既有建筑屋面为研究对象,借助Grasshopper工具搭建参数化模拟优化平台,以总日照辐射量和单位面积日照辐射量作为性能评价指标,对坡屋面增设光伏阵列形态设计进行多目标优化研究,得到屋面坡度、面积和朝向确定条件下光伏阵列的一系列几何形态优化设计方案,经筛选后优化方案较对照方案有较大提升。并对其进行数据分析,发现以优化性能目标为方向的几何形态设计建议:阵列倾角取场地条件范围下最大值;同时光伏阵列宽距比满足倾角的正弦函数关系,以此方案设计的光伏阵列的单位面积日照辐射量和总日照辐射量相对符合经济效益需求。明确了该多目标优化方法流程对既有建筑屋面光伏阵列设计的积极作用。

High temperature deformation behavior and optimization of hot compression process parameters in TC11 titanium alloy with coarse lamellar original microstructure

The high temperature deformation behaviors of α＋β type titanium alloy TC11 （Ti-6.5Al-3.5Mo-1.5Zr-0.3Si） with coarse lamellar starting microstructure were investigated based on the hot compression tests in the temperature range of 950-1100 ℃ and the strain rate range of 0.001-10 s-1. The processing maps at different strains were then constructed based on the dynamic materials model, and the hot compression process parameters and deformation mechanism were optimized and analyzed, respectively. The results show that the processing maps exhibit two domains with a high efficiency of power dissipation and a flow instability domain with a less efficiency of power dissipation. The types of domains were characterized by convergence and divergence of the efficiency of power dissipation, respectively. The convergent domain in a＋fl phase field is at the temperature of 950-990 ℃ and the strain rate of 0.001-0.01 s^-1, which correspond to a better hot compression process window of α＋β phase field. The peak of efficiency of power dissipation in α＋β phase field is at 950 ℃ and 0.001 s 1, which correspond to the best hot compression process parameters of α＋β phase field. The convergent domain in β phase field is at the temperature of 1020-1080 ℃ and the strain rate of 0.001-0.1 s^-l, which correspond to a better hot compression process window of β phase field. The peak of efficiency of power dissipation in ℃ phase field occurs at 1050 ℃ over the strain rates from 0.001 s^-1 to 0.01 s^-1, which correspond to the best hot compression process parameters of ,8 phase field. The divergence domain occurs at the strain rates above 0.5 s^-1 and in all the tested temperature range, which correspond to flow instability that is manifested as flow localization and indicated by the flow softening phenomenon in stress-- strain curves. The deformation mechanisms of the optimized hot compression process windows in a＋β and β phase fields are identified to be spheroidizing and dynamic recrystallizing controlled by self-diffusion mechanism, respectively. The microstructure observation of the deformed specimens in different domains matches very well with the optimized results.

Chemical etching process of copper electrode for bioelectrical impedance technology

In order to obtain bioelectrical impedance electrodes with high stability, the chemical etching process was used to fabricate the copper electrode with a series of surface microstructures. By changing the etching processing parameters, some comparison experiments were performed to reveal the influence of etching time, etching temperature, etching liquid concentration, and sample sizes on the etching rate and surface microstructures of copper electrode. The result shows that the etching rate is decreased with increasing etching time, and is increased with increasing etching temperature. Moreover, it is found that the sample size has little influence on the etching rate. After choosing the reasonable etching liquid composition （formulation 3）, the copper electrode with many surface microstructures can be obtained by chemical etching process at room temperature for 20 rain. In addition, using the alternating current impedance test of electrode-electrode for 24 h, the copper electrode with a series of surface microstructures fabricated by the etching process presents a more stable impedance value compared with the electrocardiograph （ECG） electrode, resulting from the reliable surface contact of copper electrode-electrode.

Effects of process parameters on mechanical properties and microstructures of creep aged 2124 aluminum alloy

A series of tests were carried microstructures of 2124 aluminum alloy in increase of aging time, temperature and low-to-peak-to-low manner. No significant out to investigate the effects of process parameters on mechanical properties and creep aging process. The results show that creep strain and creep rate increase with the applied stress. The hardness of specimen varies with aging time and stress in a effect of temperature on hardness of material is seen in the range of 185-195 ℃. The optimum mechanical properties are obtained at the conditions of （200 MPa, 185 ℃, 8 h） as the result of the coexistence of strengthening S＂ and S＇ phases in the matrix by transmission electron microscopy （TEM）. TEM observation shows that applied stress promotes the formation and growth of precioitates and no obvious stress orientation effect is observed in the matrix.

基于图论的工序公差设计及优化

基于图论的工序公差设计及优化的研究，构建参数化工序树，通过对参数化工序树节点的搜索确定工序公差，构建工序公差设计模型，给出工序公差约束条件。同时，对工序公差进行优化设计研究，构建工序公差优化设计模型，并采用GA算法得以实现。

Prediction and optimization of process parameter of friction stir welded AA5083-H111 aluminum alloy using response surface methodology

A systematic approach was presented to develop the empirical model for predicting the ultimate tensile strength of AA5083-H111 aluminum alloy which is widely used in ship building industry by incorporating friction stir welding(FSW) process parameters such as tool rotational speed,welding speed,and axial force.FSW was carried out considering three-factor five-level central composite rotatable design with full replications technique.Response surface methodology(RSM) was applied to developing linear regression model for establishing the relationship between the FSW process parameters and ultimate tensile strength.Analysis of variance(ANOVA) technique was used to check the adequacy of the developed model.The FSW process parameters were also optimized using response surface methodology(RSM) to maximize the ultimate tensile strength.The joint welded at a tool rotational speed of 1 000 r/min,a welding speed of 69 mm/min and an axial force of 1.33 t exhibits higher tensile strength compared with other joints.

高校校园碳排放评估方法及应用研究——以华中科技大学主校区为例

近年来,温室气体大规模排放对环境的影响日益突出,遏制碳排放成为全人类共识。高校校园人口密度大,能耗水平高,其碳排放总量巨大。在中国推行低碳城市和可持续发展的大背景下,建设低碳校园是其中的重要环节,而对高校校园碳排放的准确评估和动态监测是关键的技术前提。本文构建了适用于我国高校校园的碳排放评估体系,发展了具体碳排放计算模型,基于Grasshopper参数化平台构建了碳排放计算工具,实现了对高校校园碳排放的评估计算以及结果可视化,最后以华中科技大学主校区为例进行碳排放评估分析,根据评估结果提出了优化意见。

Effects of MgO on densification and consolidation of oxidized pellets

The calcined magnesite was utilized as a kind of MgO bearing additive to produce MgO bearing pellets. The effects of MgO on densification and consolidation of pellets were investigated. The experimental results show that, at the same process parameters, the porosity and pore size distribution of green pellets have no evident relation with the MgO bearing additive, pore size of green pellets is between 15 μm and 35 μm and the porosity of green pellets is about 34%. There is a densification and consolidation phenomenon during the induration process; the pore size and porosity of product pellets decrease gradually; and the structure of product pellets becomes dense. MgO makes a negative effect on the densification and consolidation of product pellets, the densification ratio of pellets decreases from 46.3% to 28.6% with the addition of MgO bearing additive from 0 to 2.0 %. The porosity and the pore size of product pellets increase gradually with the increase of MgO content; When the mass fraction of MgO bearing additive increases from 0 to 2.0%, the pore size of product pellet increases and the pore size distributes in a large range. Also, the porosity increases from 18.61% to 24.06%.

Optimization of process parameters to maximize ultimate tensile strength of friction stir welded dissimilar aluminum alloys using response surface methodology

Aluminium alloys generally present low weldability by traditional fusion welding process. Development of the friction stir welding （FSW） has provided an alternative improved way of producing aluminium joints in a faster and reliable manner. The quality of a weld joint is stalwartly influenced by process parameter used during welding. An approach to develop a mathematical model was studied for predicting and optimizing the process parameters of dissimilar aluminum alloy （AA6351 T6-AA5083 Hlll）joints by incorporating the FSW process parameters such as tool pin profile, tool rotational speed welding speed and axial force. The effects of the FSW process parameters on the ultimate tensile strength （UTS） of friction welded dissimilar joints were discussed. Optimization was carried out to maximize the UTS using response surface methodology （RSM） and the identified optimum FSW welding parameters were reported.

Experimental research on oxidation of phenol by activated persulfate

In this paper, the optimum process parameters were obtained through treating phenol of simulated semi-coking wastewater using heat, Fe2＋, Fe^0 and semi-coke to catalyze persulfate. The results of phenol decomposition using PS catalyzed by heating, Fe2＋, Fe^0 and semi-coke were compared for selecting a better activating way. The article investigated the effects of temperature, catalyzer dosage, pH value and reaction time. The experiment showed the four methods can all catalyzed the process. Under the experimental conditions of heating, Fe2＋, Fe^0 and semi-coke degradation rate could reach to 20.7%, 75.1%, 94.5% and 40.0%, respectively. On this basis, this study established an Lt6（45） table to analyze the main influencing factors in semi-coke/Fe^0 catalyzing system. Under the optimum conditions, the degradation rate of Phenol reached to 93.6%. However, the PS dosage was reduced by 14.4%.

Optimization of processing parameters for microwave drying of selenium-rich slag using incremental improved back-propagation neural network and response surface methodology

In the non-linear microwave drying process, the incremental improved back-propagation （BP） neural network and response surface methodology （RSM） were used to build a predictive model of the combined effects of independent variables （the microwave power, the acting time and the rotational frequency） for microwave drying of selenium-rich slag. The optimum operating conditions obtained from the quadratic form of the RSM are： the microwave power of 14.97 kW, the acting time of 89.58 min, the rotational frequency of 10.94 Hz, and the temperature of 136.407 ℃. The relative dehydration rate of 97.1895% is obtained. Under the optimum operating conditions, the incremental improved BP neural network prediction model can predict the drying process results and different effects on the results of the independent variables. The verification experiments demonstrate the prediction accuracy of the network, and the mean squared error is 0.16. The optimized results indicate that RSM can optimize the experimental conditions within much more broad range by considering the combination of factors and the neural network model can predict the results effectively and provide the theoretical guidance for the follow-up production process.

Study of M-ZSM-5 nanocatalysts(M: Cu, Mn, Fe, Co …) for selective catalytic reduction of NO with NH_3: Process optimization by Taguchi method

A series of different transition metals(V,Co,Cr,Mn,Fe,Ni,Cu and Zn) promoted H-ZSM-5 catalysts were prepared by impregnation method and characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The catalytic activity of these catalysts was evaluated for the selective catalytic reduction(SCR) of NO with NH_3 as reductant in the presence of oxygen.The results revealed that the catalytic activity of Cu-ZSM-5 nanocatalyst for NO conversion to N_2 was 80%at 300 ℃,which was the best among various promoted metals.Design of experiments(DOEs) with Taguchi method was employed to optimize NH_3-SCR process parameters such as NH_3/NO ratio,O_2 concentration,and gas hourly space velocity(GHSV) over Cu-ZSM-5 nanocatalyst at 250 and 300 ℃.Results showed that the most important parameter in NH_3-SCR of NO is O_2 concentration;followed by NH_3/NO ratio and GHSV has little importance.The NO conversion to N_2 of 63.1%and 94.86%was observed at 250℃ and 300℃,respectively under the obtained optimum conditions.

Parametric optimization of friction stir welding process of age hardenable aluminum alloys-ANFIS modeling

A comparative approach was performed between the response surface method(RSM) and the adaptive neuro-fuzzy inference system(ANFIS) to enhance the tensile properties, including the ultimate tensile strength and the tensile elongation, of friction stir welded age hardenable AA6061 and AA2024 aluminum alloys. The effects of the welding parameters, namely the tool rotational speed, welding speed, axial load and pin profile, on the ultimate tensile strength and the tensile elongation were analyzed using a three-level, four-factor Box-Behnken experimental design. The developed design was utilized to train the ANFIS models. The predictive capabilities of RSM and ANFIS were compared based on the root mean square error, the mean absolute error, and the correlation coefficient based on the obtained data set. The results demonstrate that the developed ANFIS models are more effective than the RSM model.

Variation of biological and hydrological parameters and nitrogen removal optimization of modified Carrousel oxidation ditch process

To enhance the nitrogen removal,a systemic monitoring of the biological and hydrological parameters of Carrousel oxidation ditch in Chongqing Jingkou Wastewater Treatment Plant was carried out to study the feasibility of simultaneous nitrification and denitrification(SND).The variation and distribution of parameters such as flow velocity,concentration of dissolved oxygen(DO) and mixed liquor suspended solids(MLSS) in oxidation ditch were monitored and analyzed,which were major control factors for SND.The results showed that,the dimensional distribution of flow velocity,DO and MLSS were affected significantly by the operation condition of the aeration wheels.With all the four aeration wheels being in operation,DO and flow velocity were higher and the mixing of MLSS was sufficient.With three aeration wheels being in operation,the flow velocity in most of the bottom areas was enough to meet the basic requirements of no deposition,and the anaerobic region and aerobic region could exist simultaneously in one oxidation ditch,which was helpful to the process of SND.According to spatial distribution characteristics of the flow velocity,DO and soluble components under optimized condition,different functional zones of biochemical reaction in the Carrousel oxidation ditch system were defined,which might contribute to the optimization control and SND of Carrousel oxidation ditch.

Study on Hydrocracking of VGO Derived from Kazakhstan-Russian Mixed Crude

This article investigates the influence of the property of VGO derived from the Kazakhstan- Russian mixed crude on the hydrocracking catalyst. The influence of reaction temperature, reaction pressure, space velocity and hydrogen/oil ratio on the distribution and quality of products was analyzed with the optimal process regime determined, when the VGO was hydrocracked in the presence of the FC-16 catalyst.