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Performance design of a cryogenic air separation unit for variable working conditions using the lumped

Jinghua XU, Tiantian WANG, Qianyong CHEN, Shuyou ZHANG, Jianrong TAN

《机械工程前沿（英文）》 2020年 第15卷 第1期   页码 24-42 doi: 10.1007/s11465-019-0558-6

摘要： Large-scale cryogenic air separation units (ASUs), which are widely used in global petrochemical and semiconductor industries, are being developed with high operating elasticity under variable working conditions. Different from discrete processes in traditional machinery manufacturing, the ASU process is continuous and involves the compression, adsorption, cooling, condensation, liquefaction, evaporation, and distillation of multiple streams. This feature indicates that thousands of technical parameters in adsorption, heat transfer, and distillation processes are correlated and merged into a large-scale complex system. A lumped parameter model (LPM) of ASU is proposed by lumping the main factors together and simplifying the secondary ones to achieve accurate and fast performance design. On the basis of material and energy conservation laws, the piecewise-lumped parameters are extracted under variable working conditions by using LPM. Takagi–Sugeno (T–S) fuzzy interval detection is recursively utilized to determine whether the critical point is detected or not by using different thresholds. Compared with the traditional method, LPM is particularly suitable for “rough first then precise” modeling by expanding the feasible domain using fuzzy intervals. With LPM, the performance of the air compressor, molecular sieve adsorber, turbo expander, main plate-fin heat exchangers, and packing column of a 100000 Nm O /h large-scale ASU is enhanced to adapt to variable working conditions. The designed value of net power consumption per unit of oxygen production (kW/(Nm O )) is reduced by 6.45%.

关键词： performance design     air separation unit (ASU)     lumped parameter model (LPM)     variable working conditions     T–S fuzzy interval detection    

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Characteristics Analysis of Integrated CAES and CFPP Trigeneration System Considering Working Conditions

Jiajia Li,Peigang Yan,Guowen Zhou,Xingshuo Li,Qiang Li,Jinfu Liu,Daren Yu,

《工程（英文）》 doi: 10.1016/j.eng.2023.06.015

摘要： To meet the goal of worldwide decarbonization, the transformation process toward clean and green energy structures has accelerated. In this context, coal-fired power plant (CFPPs) and large-scale energy storage represented by compressed air energy storage (CAES) technology, are tasked with increasing renewable resource accommodation and maintaining the power system security. To achieve this, this paper proposes the concept of a CFPP–CAES combined cycle and a trigenerative system based on that. Considering the working conditions of the CFPP, thermal characteristics of three typical operation modes were studied and some general regularities were identified. The results of various potential integration schemes discussion indicated that extracting water from low-temperature points in the feedwater system to cool pressurized air and simultaneously increase the backwater temperature is beneficial for improving performance. In addition, preheating the pressurized air before the air expanders via low-grade water in the feedwater system as much as possible and reducing extracted steam contribute to increasing the efficiency. With the optimal integration scheme, 2.85 tonnes of coal can be saved per cycle and the round-trip efficiency can be increased by 2.24%. Through the cogeneration of heat and power, the system efficiency can reach 77.5%. In addition, the contribution degree of the three compression heat utilization methods to the performance improvement ranked from high to low, is preheating the feedwater before the boiler, supplying heat, and flowing into the CFPP feedwater system. In the cooling energy generation mode, the system efficiency can be increased to over 69%. Regardless of the operation mode, the benefit produced by integration is further enhanced when the CFPP operates at higher operating conditions because the coupling points parameters are changed. In addition, the dynamic payback period can be shortened by 11.33 years and the internal rate of return increases by 5.20% under a typical application scenario. Regarding the effect of different application scenarios in terms of economics, investing in the proposed system is more appropriate in regions with multiple energy demands, especially heating demand. These results demonstrate the technical advantages of the proposed system and provide guiding principles for its design, operation, and project investment.

关键词： Compressed air energy storage     CFPP–CAES combined cycle     Thermodynamic performance     Technical economics    

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基于实际工作状态的多跨悬索桥中间塔静力试验模型设计

吉林,王陶,吴寒亮

《中国工程科学》 2012年 第14卷 第5期   页码 66-70

摘要：

与传统两塔悬索桥相比，多塔连跨悬索桥中间塔的约束条件、工作环境及荷载作用等均有较大差别，其对全桥安全性和使用性有显著影响。基于泰州大桥的实际工作状态（中间塔的纵向最不利工况），采用静力相似理论设计中间塔缩尺模型。通过对原桥中间塔和试验模型的数值仿真分析，从内力、位移及应变等方面比较分析原桥和试验模型的相似关系，结果表明，以几何尺寸和材料弹性模量为基本相似量所设计的试验模型，能满足中间塔主要静力性能的试验要求。

关键词： 悬索桥     中间塔     实际工作状态     相似理论     数值仿真     模型试验    

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低水多变环境下玉米叶片的光合与反射光谱特征

孙莉,苏根强,刘艳梅,赵闫闫,史刚荣

《中国工程科学》 2012年 第14卷 第3期   页码 70-75

摘要：

采用盆栽试验，以玉米品种苏玉19为试材，在每次复水第7天同时测定不同处理植株的生物量、根冠比、叶绿素荧光、气体交换以及光谱特征等指标。结果表明，持续干旱处理抑制植株生长，增加根冠比，并通过气孔限制和非气孔限制因素抑制光合作用。持续干旱处理幼苗的mSR705、chlNDI和REP均显著小于对照，但对SIPI的影响不显著。多变低水环境下玉米幼苗生长明显受到抑制，但根冠比、叶绿素荧光、气体交换以及光谱特征等指标与正常供水没有差异。可见，生物量分配、光合作用和光谱特征的维持可能是玉米适应多变低水环境的重要生理机制。

关键词： 玉米     多变低水     叶绿素荧光     气体交换     反射光谱    

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Tacholess order-tracking approach for wind turbine gearbox fault detection

Yi WANG, Yong XIE, Guanghua XU, Sicong ZHANG, Chenggang HOU

《机械工程前沿（英文）》 2017年 第12卷 第3期   页码 427-439 doi: 10.1007/s11465-017-0452-z

摘要：

Monitoring of wind turbines under variable-speed operating conditions has become an important issue in recent years. The gearbox of a wind turbine is the most important transmission unit; it generally exhibits complex vibration signatures due to random variations in operating conditions. Spectral analysis is one of the main approaches in vibration signal processing. However, spectral analysis is based on a stationary assumption and thus inapplicable to the fault diagnosis of wind turbines under variable-speed operating conditions. This constraint limits the application of spectral analysis to wind turbine diagnosis in industrial applications. Although order-tracking methods have been proposed for wind turbine fault detection in recent years, current methods are only applicable to cases in which the instantaneous shaft phase is available. For wind turbines with limited structural spaces, collecting phase signals with tachometers or encoders is difficult. In this study, a tacholess order-tracking method for wind turbines is proposed to overcome the limitations of traditional techniques. The proposed method extracts the instantaneous phase from the vibration signal, resamples the signal at equiangular increments, and calculates the order spectrum for wind turbine fault identification. The effectiveness of the proposed method is experimentally validated with the vibration signals of wind turbines.

关键词： wind turbine     variable-speed operating conditions     Vold-Kalman filtering     tacholess order tracking    

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Two-level uncapacitated lot-sizing problem considering the financing cost of working capital requirement

Yuan BIAN, David LEMOINE, Thomas G. YEUNG, Nathalie BOSTEL

《工程管理前沿（英文）》 2020年 第7卷 第2期   页码 248-258 doi: 10.1007/s42524-019-0069-5

摘要： During financial crisis, companies constantly need free cash flows to efficiently react to any uncertainty, thus ensuring solvency. Working capital requirement (WCR) has been recognized as a key factor for releasing tied up cash in companies. However, in literatures related to lot-sizing problem, WCR has only been studied in the single-level supply chain context. In this paper, we initially adopt WCR model for a multi-level case. A two-level (supplier–customer) model is established on the basis of the classic multi-level lot-sizing model integrated with WCR financing cost. To tackle this problem, we propose sequential and centralized approaches to solve the two-level case with a serial chain structure. The ZIO (Zero Inventory Ordering) property is further confirmed valid in both cases. This property allows us to establish a dynamic programming-based algorithm, which solves the problem in O(T ). Finally, numerical tests show differences in optimal plans obtained by both approaches and the influence of varying delays in payment on the WCR of both actors.

关键词： two-level ULS problem     lot-sizing     working capital requirement     ZIO property     infinite production capacity    

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A method to calculate working capacity space of multi-DOF manipulator and the application in excavating

Baochen WEI, Feng GAO

《机械工程前沿（英文）》 2012年 第7卷 第2期   页码 109-119 doi: 10.1007/s11465-012-0323-6

摘要：

Working capacity refers to the velocity output and force output of a manipulator. It is usually be represented by output capacity space. In this paper, the method of Linear Programming and a geometric method are proposed to calculate working capacity spaces in different situations. With the consideration of gravity effect of every component, the output force capacity space of heavy duty manipulators is calculated. The results show that the effect of the gravity is a translation of the capacity space. This paper gives a method for the output capacity express especially for heavy duty manipulators. The output capacity space can be helpful to the driving parameters selection. With the consideration of the gravity effect of every component and the friction at the joints, the excavating force capacity space of the heavy-load excavating mechanism is calculated and is represented as a multi-dimensional polytope. The results show that the effect of the gravity and friction is to translational act on the capacity space.

关键词： working capacity     multi-DOF manipulator     capacity polytope     excavating mechanism    

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Analysis of planetary gear transmission in non-stationary operations

Fakher CHAARI, Mohamed Slim ABBES, Fernando Viadero RUEDA, Alfonso Fernandez del RINCON, Mohamed HADDAR

《机械工程前沿（英文）》 2013年 第8卷 第1期   页码 88-94 doi: 10.1007/s11465-013-0361-8

摘要：

Planetary gearboxes operate usually in non-stationary conditions generated mainly by variable loads applied to these transmissions. In order to understand the dynamic behavior of planetary gearboxes in such conditions, a mathematic model is developed including driving unit, transmission and load. The variability of load induces a variable speed of the transmission which is taken into account when characterizing the main dynamic parameter of the transmission which is the mesh stiffness function. This function is not periodic following the variability of the transmission speed. The computation of the dynamic response shows an intimate relation between the vibration amplitude level and the load value. As the load increase the vibration level increase. A combined amplitude and frequency modulation is observed which is well characterized using Short Time Fourier transform more suited than the spectral analysis.

关键词： planetary gearbox     non-stationary conditions     variable load     dynamic response     time frequency analysis    

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Unit commitment using dynamic programming–an exhaustive working of both classical and stochastic approach

Balasubramaniyan SARAVANAN, Surbhi SIKRI, K. S. SWARUP, D. P. KOTHARI

《能源前沿（英文）》 2013年 第7卷 第3期   页码 333-341 doi: 10.1007/s11708-013-0259-5

摘要： In the present electricity market, where renewable energy power plants have been included in the power systems, there is a lot of unpredictability in the demand and generation. There are many conventional and evolutionary programming techniques used for solving the unit commitment (UC) problem. Dynamic programming (DP) is a conventional algorithm used to solve the deterministic problem. In this paper DP is used to solve the stochastic model of UC problem. The stochastic modeling for load and generation side has been formulated using an approximate state decision approach. The programs were developed in a MATLAB environment and were extensively tested for a four-unit eight-hour system. The results obtained from these techniques were validated with the available literature and outcome was good. The commitment is in such a way that the total cost is minimal. The novelty of this paper lies in the fact that DP is used for solving the stochastic UC problem.

关键词： unit commitment (UC)     deterministic     stochastic     dynamic programming (DP)     optimization     state diagram    

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Mechanical design, modeling, and identification for a novel antagonistic variable stiffness dexterous

《机械工程前沿（英文）》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0691-5

摘要： This study traces the development of dexterous hand research and proposes a novel antagonistic variable stiffness dexterous finger mechanism to improve the safety of dexterous hand in unpredictable environments, such as unstructured or man-made operational errors through comprehensive consideration of cost, accuracy, manufacturing, and application. Based on the concept of mechanical passive compliance, which is widely implemented in robots for interactions, a finger is dedicated to improving mechanical robustness. The finger mechanism not only achieves passive compliance against physical impacts, but also implements the variable stiffness actuator principle in a compact finger without adding supererogatory actuators. It achieves finger stiffness adjustability according to the biologically inspired stiffness variation principle of discarding some mobilities to adjust stiffness. The mechanical design of the finger and its stiffness adjusting methods are elaborated. The stiffness characteristics of the finger joint and the actuation unit are analyzed. Experimental results of the finger joint stiffness identification and finger impact tests under different finger stiffness presets are provided to verify the validity of the model. Fingers have been experimentally proven to be robust against physical impacts. Moreover, the experimental part verifies that fingers have good power, grasping, and manipulation performance.

关键词： multifingered hand     mechanism design     robot safety     variable stiffness actuator    

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Effect of variable heat capacities on performance of an irreversible Miller heat engine

Xingmei YE

《能源前沿（英文）》 2012年 第6卷 第3期   页码 280-284 doi: 10.1007/s11708-012-0203-0

摘要： Based on the variable heat capacities of the working fluid, the irreversibility coming from the compression and expansion processes, and the heat leak losses through the cylinder wall, an irreversible cycle model of the Miller heat engine was established, from which expressions for the efficiency and work output of the cycle were derived. The performance characteristic curves of the Miller heat engine were generated through numerical calculation, from which the optimal regions of some main parameters such as the work output, efficiency and pressure ratio were determined. Moreover, the influence of the compression and expansion efficiencies, the variable heat capacities and the heat leak losses on the performance of the cycle was discussed in detail, and consequently, some significant results were obtained.

关键词： Miller cycle     variable heat capacity     irreversibility     parametric optimization    

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Exergy analysis of R1234ze(Z) as high temperature heat pump working fluid with multi-stage compression

Bin HU, Di WU, L.W. WANG, R.Z. WANG

《能源前沿（英文）》 2017年 第11卷 第4期   页码 493-502 doi: 10.1007/s11708-017-0510-6

摘要： In this paper, the simulation approach and exergy analysis of multi-stage compression high temperature heat pump (HTHP) systems with R1234ze(Z) working fluid are conducted. Both the single-stage and multi-stage compression cycles are analyzed to compare the system performance with 120°C pressurized hot water supply based upon waste heat recovery. The exergy destruction ratios of each component for different stage compression systems are compared. The results show that the exergy loss ratios of the compressor are bigger than that of the evaporator and the condenser for the single-stage compression system. The multi-stage compression system has better energy and exergy efficiencies with the increase of compression stage number. Compared with the single-stage compression system, the coefficient of performance (COP) improvements of the two-stage and three-stage compression system are 9.1% and 14.6%, respectively. When the waste heat source temperature is 60°C, the exergy efficiencies increase about 6.9% and 11.8% for the two-stage and three-stage compression system respectively.

关键词： multi-stage compression     high temperature heat pump     heat recovery     exergy destruction     R1234ze(Z) working fluid    

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A neural network-based production process modeling and variable importance analysis approach in corn

《化学科学与工程前沿（英文）》 2023年 第17卷 第3期   页码 358-371 doi: 10.1007/s11705-022-2190-y

摘要： Corn to sugar process has long faced the risks of high energy consumption and thin profits. However, it’s hard to upgrade or optimize the process based on mechanism unit operation models due to the high complexity of the related processes. Big data technology provides a promising solution as its ability to turn huge amounts of data into insights for operational decisions. In this paper, a neural network-based production process modeling and variable importance analysis approach is proposed for corn to sugar processes, which contains data preprocessing, dimensionality reduction, multilayer perceptron/convolutional neural network/recurrent neural network based modeling and extended weights connection method. In the established model, dextrose equivalent value is selected as the output, and 654 sites from the DCS system are selected as the inputs. LASSO analysis is first applied to reduce the data dimension to 155, then the inputs are dimensionalized to 50 by means of genetic algorithm optimization. Ultimately, variable importance analysis is carried out by the extended weight connection method, and 20 of the most important sites are selected for each neural network. The results indicate that the multilayer perceptron and recurrent neural network models have a relative error of less than 0.1%, which have a better prediction result than other models, and the 20 most important sites selected have better explicable performance. The major contributions derived from this work are of significant aid in process simulation model with high accuracy and process optimization based on the selected most important sites to maintain high quality and stable production for corn to sugar processes.

关键词： big data     corn to sugar factory     neural network     variable importance analysis    

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On the improvement design of dynamic characteristics for the roller follower of a variable-speed plate

Hui Ching FAN, Hong Sen YAN

《机械工程前沿（英文）》 2012年 第7卷 第1期   页码 5-15 doi: 10.1007/s11465-012-0310-y

摘要：

Without modifying the cam contour, a cam mechanism with a variable input speed trajectory offers an alternative solution to flexibly achieve kinematic and dynamic characteristics, and then decrease the follower’s residual vibration. Firstly, the speed trajectory of cam is derived by employing Bezier curve, and motion continuity conditions are investigated. Then the motion characteristics between the plate cam and its roller follower are derived. To analyze the residual vibration, a single degree of freedom dynamic model of the elastic cam-follower system is introduced. Based on the motion equation derived from the dynamic model, the residual vibration of the follower is yielded. The design procedure to improve the kinematic and dynamic motion characteristics is presented and two design examples with discussions are provided. Finally, the simulations of the kinematic and dynamic models by ADAMS are carried out and verified that the design models as well as the performances of the mechanism are feasible.

关键词： cam mechanism     variable input speed     kinematic design     dynamic design     optimal design    

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Working Up Green, and Living Up Green

Ji-shan He

《工程管理前沿（英文）》 2014年 第1卷 第1期   页码 2-2 doi: 10.15302/J-FEM-2014002

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标题 作者 时间 类型 操作

Performance design of a cryogenic air separation unit for variable working conditions using the lumped

Jinghua XU, Tiantian WANG, Qianyong CHEN, Shuyou ZHANG, Jianrong TAN

期刊论文

Characteristics Analysis of Integrated CAES and CFPP Trigeneration System Considering Working Conditions

Jiajia Li,Peigang Yan,Guowen Zhou,Xingshuo Li,Qiang Li,Jinfu Liu,Daren Yu,

期刊论文

基于实际工作状态的多跨悬索桥中间塔静力试验模型设计

吉林,王陶,吴寒亮

期刊论文

低水多变环境下玉米叶片的光合与反射光谱特征

孙莉,苏根强,刘艳梅,赵闫闫,史刚荣

期刊论文

Tacholess order-tracking approach for wind turbine gearbox fault detection

Yi WANG, Yong XIE, Guanghua XU, Sicong ZHANG, Chenggang HOU

期刊论文

Two-level uncapacitated lot-sizing problem considering the financing cost of working capital requirement

Yuan BIAN, David LEMOINE, Thomas G. YEUNG, Nathalie BOSTEL

期刊论文

A method to calculate working capacity space of multi-DOF manipulator and the application in excavating

Baochen WEI, Feng GAO

期刊论文

Analysis of planetary gear transmission in non-stationary operations

Fakher CHAARI, Mohamed Slim ABBES, Fernando Viadero RUEDA, Alfonso Fernandez del RINCON, Mohamed HADDAR

期刊论文

Unit commitment using dynamic programming–an exhaustive working of both classical and stochastic approach

Balasubramaniyan SARAVANAN, Surbhi SIKRI, K. S. SWARUP, D. P. KOTHARI

期刊论文

Mechanical design, modeling, and identification for a novel antagonistic variable stiffness dexterous

期刊论文

Effect of variable heat capacities on performance of an irreversible Miller heat engine

Xingmei YE

期刊论文

Exergy analysis of R1234ze(Z) as high temperature heat pump working fluid with multi-stage compression

Bin HU, Di WU, L.W. WANG, R.Z. WANG

期刊论文

A neural network-based production process modeling and variable importance analysis approach in corn

期刊论文

On the improvement design of dynamic characteristics for the roller follower of a variable-speed plate

Hui Ching FAN, Hong Sen YAN

期刊论文

Working Up Green, and Living Up Green

Ji-shan He

期刊论文