Data-driven intelligent modeling framework for the steam cracking process

Steam cracking is the dominant technology for producing light olefins,which are believed to be the foundation of the chemical industry.Predictive models of the cracking process can boost production efficiency and profit margin.Rapid advancements in machine learning research have recently enabled data-driven solutions to usher in a new era of process modeling.Meanwhile,its practical application to steam cracking is still hindered by the trade-off between prediction accuracy and computational speed.This research presents a framework for data-driven intelligent modeling of the steam cracking process.Industrial data preparation and feature engineering techniques provide computational-ready datasets for the framework,and feedstock similarities are exploited using k-means clustering.We propose LArge-Residuals-Deletion Multivariate Adaptive Regression Spline(LARD-MARS),a modeling approach that explicitly generates output formulas and eliminates potentially outlying instances.The framework is validated further by the presentation of clustering results,the explanation of variable importance,and the testing and comparison of model performance.

Modeling and Optimization of Ethane Steam Cracking Process in An Industrial Tubular Reactor with Improved Reaction Scheme

Ethane steam cracking process in an industrial reactor was investigated.An one-demsional(1D)steady-state model was developed firstly by using an improved molecular reaction scheme and was then simulated in Aspen Plus.A comparison of model results with industrial data and previously reported results showed that the model can predict the process kinetics more accurately.In addition,the validated model was used to study the effects of different process variables,including coil outlet temperature(COT),steam-to-ethane ratio and residence time on ethane conversion,ethylene selectivity,products yields,and coking rate.Finally,steady-state optimization was conducted to the operation of industrial reactor.The COT and steam-to-ethane ratio were taken as decision variables to maximize the annual operational profit.

Effects of Combined Instantaneous High-Pressure and MediumTemperature on the Retention of Total Vitamin Cin Wax Gourd Juices

Based on the instantaneous high-pressure(IHP)produced by high-pressure single pole-cylinder pump, the effects of combining this pressure with medium temperature on the retention of total vitamin C(Vc)in wax gourd juices were investigated under 20 - 80 MPa, 35 - 58℃, pH 3. 0 - 6. 0 and processing time 0-8 min. Results showed that the loss of Vc increased with elevated processing temperatures(50 MPa, 4 min). When the temperature of raw juices was 35℃, the retention of total Vc was higher under 40 - 60 MPa than that under the pressure < 40 MPa or > 60 MPa, and it was up to 94%(4 min). The retention of total Vc decreases slowly within 6 min, but rapidly after 6 min. The pH can also influence the retention of total Vc, and this retention can come to a highest point at pH 6.0.

Targeted Catalytic Cracking to Olefins(TCO):Reaction Mechanism,Production Scheme,and Process Perspectives

Light olefins are important organic building blocks in the chemicals industry.The main low-carbon olefin production methods,such as catalytic cracking and steam cracking,have considerable room for improvement in their utilization of hydrocarbons.This review provides a thorough overview of recent studies on catalytic cracking,steam cracking,and the conversion of crude oil processes.To maximize the production of light olefins and reduce carbon emissions,the perceived benefits of various technologies are examined.Taking olefin generation and conversion as a link to expand upstream and downstream processes,a targeted catalytic cracking to olefins(TCO)process is proposed to meet current demands for the transformation of oil refining into chemical production.The main innovations of this process include a multiple feedstock supply,the development of medium-sized catalysts,and a diameter-transformed fluidizedbed reactor with different feeding schemes.In combination with other chemical processes,TCO is expected to play a critical role in enabling petroleum refining and chemical processes to achieve low carbon dioxide emissions.

A Comparison Study between the Newly Developed Vertical Wells Steam Assisted Gravity Drainage and the Conventional SAGD Process

A numerical simulation study using the CMG-STAR Simulator was performed to compare the performance of the newly developed process (VWSAGD) utilizing vertical wells to enhance heavy oil recovery during steam assisted gravity drainage against the conventional steam assisted gravity drainage process which utilized horizontal wells (HWSAGD) under the same operating conditions. Two identical reservoir models were simulated for the two processes using 3-Dimensional, black heavy oil model (14° API). Each reservoir type consists of 49 × 49 × 20 grid blocks on a 5-acre model, which incorporated a typical heavy oil reservoir rock and fluid properties taken from the SPE case study, stspe001.dat (CMG 2015 release). A sensitivity analysis for both processes was performed for the grid density, soaking time, steam quality, bottom hole producing pressure, steam injection rate, reservoir thickness, reservoir area, and horizontal to vertical permeability anisotropy. More preferable reservoir conditions are those such as high horizontal to vertical permeability ratio, thick reservoir oil zones, as well as improved reservoir recovery for the VWSAGD process. Under unfavorable conditions such as thin reservoir oil zones, an improved reservoir recovery response was limited for the VWSAGD process and could be uneconomical in real field cases. Finally, the simulation results from this study include cumulative recoveries, Steam oil ratios, produced water-oil ratios, pressure and temperature distributions, and production rates. In addition, the results from this study have shown that the new VWSAGD process is more favorable than the conventional HWSAGD process.

Short wet-steam dyeing process of cotton fabrics with reactive dyes

The effects of Reactive Black 5 utilized to cotton fabrics by short wet-steam process on the dyeing properties were investigated. This study will provide a theoretical reference for short wet-steam process of cotton fabrics with bifunctional reactive dyes. The optimal amount of Selilao agent was 20 g/L, while the soaping and rubbing fastness of the dyed cotton fabrics were both reached to 4-5 rating.

九蒸九制对黄精中AGEs含量、多糖结构及体外活性的影响

为初步判断九蒸九制黄精多糖含量下降的主要原因及九蒸九制对黄精多糖体外活性的影响,本文测定了九蒸九制黄精中5-羟甲基糠醛(5-HMF)及晚期糖基化终产物(AGEs)的含量,考察了九蒸九制前后黄精纯化多糖的结构变化,并分析这些变化对黄精体外活性的影响。结果表明九蒸九制黄精发生了美拉德反应,5-HMF含量为(631.3±21.5)μg/g,羧甲基赖氨酸(CML)和羧乙基赖氨酸(CEL)含量分别为(342.4±11.3)μg/g和(63.7±9.8)μg/g。并对黄精多糖的结构及组成产生了不同程度的影响,葡萄糖(Glc)含量有所增长,甘露糖(Man)及半乳糖醛酸(GalUA)的含量有明显降低,Man从34.53%降至17.06%,GalUA从9.59%降至1.77%。研究表明,黄精在九蒸九制的加工过程中发生了美拉德反应,并产生了一定量的AGEs,同时,九蒸九制法在一定程度提高了黄精多糖的体外降糖活性。

甘薯生全粉添加量对馒头制作工艺及品质的影响

以甘薯-小麦混粉为原料,探究甘薯生全粉馒头制作配方工艺以及甘薯生全粉添加量对馒头基本成分和物化特性的影响。结果表明,甘薯馒头制作配方最优工艺为甘薯生全粉添加量30%、加水量55%、α-淀粉酶添加量0.02%、普鲁兰酶添加量0.75%,此时甘薯生全粉馒头感官评分最高为84.9。随着甘薯生全粉添加量增加,甘薯馒头淀粉和总膳食纤维含量逐渐增大,蛋白质含量逐渐减小,可溶性糖呈不规律变化趋势且变化幅度较小。随着甘薯生全粉添加量增加,甘薯馒头色度WH值、比容逐渐减小,硬度和胶黏性逐渐增加,黏性、回复性、黏聚性和弹性逐渐减小。随着甘薯生全粉添加量增加,冻藏后复蒸馒头比容逐渐减小,硬度逐渐增大;在相同添加量的情况下,随着冻藏时间的延长,比容呈逐渐减小的变化趋势,硬度呈逐渐增大的变化趋势。综上所述,适当添加甘薯生全粉可制作出品质较好的馒头。

九蒸九制槐角炮制过程主要成分、物性参数及颜色的相关性分析

目的研究九蒸九制槐角炮制过程中主要成分含量、物性参数、颜色的相关性。方法采用高效液相色谱法(HPLC)同时测定槐角苷、染料木苷、芦丁和5-羟甲基糠醛的含量,紫外分光光度法测定多糖的含量;通过测定物性参数和颜色指标(L*、a*、b*),结合系统聚类分析(HCA)、主成分分析(PCA)和偏最小二乘法(PLS)研究主要成分、物性参数及颜色的相关性;采用基于指标相关性的指标权重确定(CRITIC)法对槐角九蒸九制过程的影响进行综合评价。结果含量测定及色度测量方法准确可靠,精密度、稳定性、重复性试验均良好。HCA和PCA结果均表明,槐角饮片炮制过程中一蒸一制至四蒸四制聚为一类,五蒸五制至九蒸九制聚为一类。PLS相关性分析表明,多糖、芦丁的含量与物性参数、颜色均呈显著性相关;吸水膨胀度、相对密度与颜色均呈显著性相关。综合评价显示九蒸九制槐角炮制品最佳。结论九蒸九制槐角炮制过程中主要成分含量、物性参数、颜色的总体变化具有一定规律性,将其内在成分含量与颜色、物性参数结合为揭示槐角九蒸九制炮制机理提供了依据。

大蒜挥发油的提取工艺研究

主要对大蒜挥发油的提取工艺进行了研究。研究结果显示:当大蒜量、水量和蒸馏时间均为相同定值时,大蒜粉碎程度好,出油率会增加;当料液比、蒸馏时间和粉碎程度为定值时,大蒜浸泡后,挥发油出油率高;当料液比、蒸馏时间、浸泡时间和粉碎程度为定值时,大蒜去皮与带皮,大蒜挥发油出油率无明显差别,可以带皮提取,省时省力;浸泡时间达到25 h,蒸馏时间可大大缩短。这就为挥发油的大规模生产提供了依据。

自主核电汽轮机低压内缸研制技术探究

为了提高在制自主核电汽轮机低压内缸研制水平,文章对缸的设计结构、制造工艺、加工机床等环节进行了深入剖析,拟定出缸的结构优化、工艺完善、立车改造方案,有效提高了缸的研制质量,大幅降低了缸的研制费用。先进的技术方案、优良的经济效果,为机组进一步抢占国内外市场和公司目前推进的智能制造创出了一条新思路。

野菊花精油提取工艺优化研究

以野菊花为物料,采用水蒸气蒸馏技术提取野菊花精油;以野菊花精油得率为指标,通过响应面试验优化提取工艺。结果表明:最佳提取工艺条件为液料比值17(m L/g),粉碎程度0.250 mm(60目),提取时间5.4 h。经过实验验证,得出野菊花精油得率为0.2499±0.0131%。文章为野菊花精油的进一步研究及相关产品的开发提供了理论依据。

刺竹活性炭的制备及吸附性能研究

【目的】为充分利用刺竹Bambusa sinospinosa材,提高其利用率,进一步探究刺竹活性炭的生产工艺及使用领域,以达到提升其附加值的目的。【方法】以刺竹炭为原料,使用水蒸气活化法,采用单因素实验法探究温度、时间、水蒸气量对刺竹活性炭的得率及吸附性能的影响。使用傅里叶红外吸收光谱仪(FTIR)、X-射线衍射仪(XRD)、比表面积及孔隙度分析仪(BET)、扫描电子显微镜(SEM)等对刺竹活性炭进行测试和表征。【结果】①刺竹活性炭的最优活化工艺为:活化温度875℃、活化时间2.0 h、水蒸气量0.50 L·h^(−1)。在该工艺下制备的刺竹活性炭得率为29.07%,强度达97.68%,碘吸附值为1235.03 mg·g^(−1),亚甲基蓝吸附值为276 mg·g^(−1),吸附性能较好。②红外吸收光谱表明:经活化之后峰值在3130、3010、1670 cm^(−1)等处变弱,876、809、747 cm^(−1)处吸收峰消失,但主要峰依然存在;XRD分析表明:活性炭中含有石墨α轴结构;经比表面积测试和电镜观察,最优工艺活化后的刺竹活性炭孔隙发达,孔容、孔径都有不同程度的提升,总孔容为0.489 cm^(3)·g^(−1),微孔容为0.388 cm^(3)·g^(−1),平均孔径为23.378 nm,BET比表面积为837.005 m^(2)·g^(−1)。【结论】使用最优活化工艺所制备的刺竹活性炭具有较好的性能,可用于吸附、除污等不同场合。

近红外光谱法快速检测何首乌炮制过程中多糖含量的研究

该研究基于近红外光谱技术建立了何首乌在蒸制过程中多糖含量变化的快速定量模型。采用蒽酮浓硫酸法测定了不同蒸制时间何首乌的多糖含量并结合采集的近红外光谱数据建立模型,以校正集相关系数(R^(2)_(c))、预测集相关系数(R^(2)_(p))、交叉验证集均方根误差(RMSECV)和预测集均方根误差(RMSEP)作为评价指标,考察了不同预处理方法和变量筛选方法的效果。结果显示,随着蒸制时间的延长,何首乌多糖含量先上升后下降并趋于平稳,采用平滑+变量标准化+随机蛙跳变量筛选建立的偏最小二乘法回归模型的R^(2)_(c)=0.96,RMSECV=0.74,R^(2)_(p)=0.96,RMSEP=0.28;外部预测相对偏差小于3.0%。所建立的多糖含量定量模型质量较高,预测能力较强,可为探索何首乌炮制工艺标准化及质量评价提供参考。

高压蒸汽室铸钢件砂型铸造工艺模拟研究

基于高压蒸汽室铸钢件的结构特点和铸造工艺要求,设计了该铸钢件的砂型铸造初步方案,并采用ProCAST软件进行了充型和凝固收缩数值模拟研究。结果表明:充型过程平稳,未出现浇不足现象,但在蒸汽室底座厚大部位、蒸汽室顶部凸台处出现了大体积缩孔,同时铸件中产生了分散的缩松缺陷。结合模拟结果,对缺陷部位增加了冒口和冷铁,改进后的模拟结果良好,没有缩孔缺陷。

蒸制过程中大黄鱼理化性质及品质的变化

【目的】研究大黄鱼(Larimichthys crocea)在不同蒸制时间下,其理化性质及品质的变化规律,为优化大黄鱼加工工艺提供参考。【方法】测定不同蒸制时间大黄鱼鱼肉的肌原纤维蛋白、总巯基含量、Ca^(2+)-ATP酶活力、蒸煮损失率、色差、质构、风味和脂质氧化的动态变化。【结果与结论】大黄鱼在0~4 min蒸制过程中,肌原纤维蛋白相对提取率、总巯基含量和Ca^(2+)-ATP酶活力显著性下降;0~8 min时,蒸煮损失率增加,亮度值和蓝黄值上升,电子鼻响应值在4、6 min时较大,质构硬度、弹性、咀嚼性均下降;在蒸制过程中,过氧化值和硫代巴比妥酸反应物值均上升。

仙茅酒蒸炮制工艺研究

目的:优选酒蒸仙茅最佳工艺。方法:采用正交试验设计法,以加酒量、闷润时间、蒸制时间为考察因素,以仙茅苷、苔黑酚龙胆二糖苷、苔黑酚葡萄糖苷及醇溶性浸出物含量为考察指标,优化仙茅酒蒸炮制工艺。结果:仙茅酒蒸最佳工艺为取生仙茅饮片适量,置密闭容器内,加入黄酒(每100 kg饮片加入黄酒20 kg)拌匀,闷润1 h,置锅中蒸制1 h,取出放凉,50℃干燥。结论:优化所得酒蒸仙茅炮制工艺稳定可行,仙茅酒蒸后有效成分的含量高于仙茅生品和酒炙品,酒蒸工艺优于传统酒炙工艺。

仙茅盐蒸炮制工艺优选

目的 采用正交试验设计法优选盐蒸仙茅最佳工艺。方法 采用正交试验设计法,以盐水比例、闷润时间、蒸制时间为考察因素,以仙茅苷、苔黑酚龙胆二糖苷、苔黑酚葡萄糖苷及醇溶性浸出物含量为考察指标,优化盐蒸仙茅炮制工艺。结果 仙茅盐蒸最佳工艺为取生仙茅饮片适量,置于密闭容器内,加入盐水(盐水比例1∶17.5,每100 kg仙茅饮片用2 kg食盐)拌匀,闷润1 h,置于锅中蒸制1 h,取出放凉,50℃干燥,即得。结论 优化所得盐蒸仙茅炮制工艺稳定可行,且仙茅盐蒸后有效成分的含量高于仙茅生品、传统酒炙品和盐炙品,盐蒸工艺优于盐炙工艺。

蒸制对甘薯可溶性膳食纤维提取、理化性质及消化特性的影响

目的:考察蒸制前、后甘薯中可溶性膳食纤维(SDF)提取、组成及性质的差异。方法:为获得高品质甘薯SDF,以提高提取得率和SDF总多糖含量为目标,采用响应面分析和满意度函数方法优化料液比、提取温度、提取时间3个参数,建立甘薯SDF提取工艺。从蒸制前、后的甘薯中提取得到生鲜甘薯膳食纤维(SDF-F)和蒸制甘薯膳食纤维(SDF-S),对比两者提取得率、多糖组成、膳食纤维含量以及持水力和持油力等理化性质差异,并做体外模拟消化试验。结果:优化的提取工艺参数为:料液比1∶16、提取温度40℃、提取时间40 min。在此工艺条件下,SDF-S的提取得率【(6.13±0.25)%vs(2.89±0.18)%】、中性多糖含量【(59.31±0.73)%vs(46.83±0.63)%】、酸性多糖含量【(25.36±0.48)%vs(9.60±0.14)%】、膳食纤维含量【(54.71±6.70)%vs(35.69±3.25)%】、持水力【(4.60±0.31)g/g vs(3.27±0.21)g/g)】和持油力【(3.30±0.40)g/g vs(1.82±0.28)g/g)】显著高于SDF-F(P<0.05),而SDF-F的抗消化性优于SDF-S。结论:蒸制处理虽提高了甘薯SDF的可及性,但导致SDF的抗消化性减弱。

粳糯高粱蒸煮糊化工艺优化及应用研究

该研究通过单因素及正交试验探究泡粮水温、泡粮时间、蒸煮时间对粳、糯高粱蒸煮糊化的影响,确定最佳蒸煮糊化工艺,并将其应用于酱香型白酒下沙轮次生产中。结果表明,粳高粱的最佳蒸煮糊化工艺为泡粮水温55℃、泡粮时间18 h、蒸煮时间150 min;糯高粱的最佳蒸煮糊化工艺为泡粮水温55℃、泡粮时间2.5 h、蒸煮时间80 min。将最佳蒸煮糊化工艺应用于酿酒大生产后,粳、糯高粱蒸煮黏度适中,内无生芯,含水率分别为(44.49±0.60)%、(42.62±0.37)%,糊化率分别为(30.51±0.73)%、(20.57±0.55)%,符合酱香型白酒下沙轮次生产高粱的标准蒸煮状态;进行堆积发酵和窖内发酵时升温正常,粳高粱堆积发酵最高温度达57.4℃、窖内发酵最高温度达42.5℃;糯高粱堆积发酵最高温度达59.3℃、窖内发酵最高温度达43.5℃。