Modeling, Simulation and Optimization of a Whole Industrial Catalytic Naphtha Reforming Process on Aspen Plus Platform

A new 18-lump kinetic model for naphtha catalytic reforming reactions is discussed. By developing this model as a user module, a whole industrial continuous catalytic reforming process is simulated on Aspen plus plat-form. The technique utilizes the strong databases, complete sets of modules, and flexible simulation tools of the Aspen plus system and retains the characteristics of the proposed kinetic model. The calculated results are in fair agreement with the actual operating data. Based on the model of the whole reforming process, the process is opti-mized and the optimization results are tested in the actual industrial unit for about two months. The test shows that the process profit increases about 1000yuan·h-1 averagely, which is close to the calculated result.

SIMULATION ANALYSIS AND OPTIMIZATION OF STEAM REFORMING PROCESS FOR A LARGE-SCALE AMMONIA PLANT

The present paper shows how the Schuster Schwarzschild method developed originally inastrophysics can be adopted to simulate the performance of the primary reforming furnace in an am-monia plant.This method facilitates the simulation of heat transfer and reaction in the furnace andimproves the computational efficiency.Simulation analysis is carried out to find ways of saving ener-gy.Appropriate reduction in fuel gas loading and partially shifting of the reforming load from theprimary to the secondary reformer by regulating the operating conditions can result in substantial en-ergy saving.Optimization calculations with various objective functions and constraints required areperformed.The optimization results may serve as guideline for plant operation and control.

An Integrated Water Resources and Economic Approach for Optimizing Water Allocation Policies

Reservoir/river systems analysis models are generally used in the formulation and evaluation of alternative plans for responding to water related problems and needs. One of the main problems is the water resources allocation and the cost associated with pumping, if needed. Taking the appropriate decision is considered as a techno-economic issue. The case study presented in this paper involves a complex system of three dams, two pumping stations and two diversion structures all serving an agricultural production unit. The objective of this research is to determine a suitable and feasible water allocation/pumping policy as a “trade-off” between minimizing the water deficiency and the cost of pumping. To achieve this objective, a water resources model was developed using HEC-5. A multi-criteria decision approach was implemented to determine the most appropriate water release policy and the capacity of the water diversion facilities. The parameters used were subject to a sensitivity analysis to assess their relative impact on the determined policy. The suggested release policy allows a reduction of half the total of the pumping costs with only 3% reduction in the water allocation reliability, as measured by the failure frequency of demand satisfaction and the average shortage index.

An economic analysis of China’s domestic crude oil supply policies

China's domestic oil production has lagged the growth in domestic oil consumption since the beginning of the 21st century,leading to a growing reliance on imports.In response,the Chinese government has introduced a number of policies,including import license constraints,to support domestic suppliers.In an effort to measure the economic impact of these policies we develop a short-run equilibrium model of China's wholesale oil and gas market at the provincial scale.We construct counterfactual scenarios that suggest that relaxing policies that prioritize domestic production in 2016,when the average price of Chinese oil imports was US$42 per barrel(bbl),could have increased China's import demand by 0.29 million barrels per day(MMbbl/d).This results in a substitution of 9%of China’s domestic production in 2016,and a reduction of US$2.8 billion in crude supply costs including transportation as the imported oil has more direct access to the country’s pipeline network,compared to the displaced domestic production.In addition,rising import prices since mid-2017 may provide a window of opportunity for Chinese policymakers to proceed with further deregulation of the domestic oil sector,as the short-term impact on domestic producers is reduced.

Real-Time Implementation of Quadrotor UAV Control System Based on a Deep Reinforcement Learning Approach

The popularity of quadrotor Unmanned Aerial Vehicles(UAVs)stems from their simple propulsion systems and structural design.However,their complex and nonlinear dynamic behavior presents a significant challenge for control,necessitating sophisticated algorithms to ensure stability and accuracy in flight.Various strategies have been explored by researchers and control engineers,with learning-based methods like reinforcement learning,deep learning,and neural networks showing promise in enhancing the robustness and adaptability of quadrotor control systems.This paper investigates a Reinforcement Learning(RL)approach for both high and low-level quadrotor control systems,focusing on attitude stabilization and position tracking tasks.A novel reward function and actor-critic network structures are designed to stimulate high-order observable states,improving the agent’s understanding of the quadrotor’s dynamics and environmental constraints.To address the challenge of RL hyper-parameter tuning,a new framework is introduced that combines Simulated Annealing(SA)with a reinforcement learning algorithm,specifically Simulated Annealing-Twin Delayed Deep Deterministic Policy Gradient(SA-TD3).This approach is evaluated for path-following and stabilization tasks through comparative assessments with two commonly used control methods:Backstepping and Sliding Mode Control(SMC).While the implementation of the well-trained agents exhibited unexpected behavior during real-world testing,a reduced neural network used for altitude control was successfully implemented on a Parrot Mambo mini drone.The results showcase the potential of the proposed SA-TD3 framework for real-world applications,demonstrating improved stability and precision across various test scenarios and highlighting its feasibility for practical deployment.

Tackle China's Economic Complexities by Deepening Reform and Opening Up: Macroeconomic Outlook, Policy Simulations, and Reform Implementation—A Summary of the Annual SUFE Macroeconomic Report (2018-2019)

Faced with complicated external and internal challenges, China's economy continues to see sluggish growth in 2018. Rapid accumulation of household debts, exacerbation in income inequality, tightened real sector liquidity, escalated trade tensions with the US, and weakened external demand pose key problems in China's macroeconomic landscape. The status quo is exacerbated by soaring uncertainty and weakening confidence in the face of persistent resource misallocations and institutional distortions, which cast more shadow on the already dampened consumer sentiment, sluggish private investment growth, and fallen foreign reserves. This summary report highlights the urgency of deeper structural reforms for tackling the various internal and external problems. Based on the IAR-CMM model, with both cyclical and secular factors taken into consideration, our baseline forecast of real GDP growth rate is 6.4%(6.1% using more reliable instead of the official data) in 2019. Alternative scenario analyses and policy simulations are conducted to assess the consequences of possible downside risks and the corresponding policy options needed to ensure the assumed growth targets. These analyses lead us to conclude that comprehensively deepening reform and opening up, which should be both rule-of-law based and market-oriented, with well-designed and well-conceived strategies that properly weigh short-, medium-, and long-term benefits and costs, should continue to be set as the guidance for China's transformation into a phase with sustainable and high-quality growth.

Conquering China＇s Unbalanced and Inadequate Development： Macroeconomic Outlook, Policy Simulations, and Reform Implementation--A Summary of Annual SUFE Macroeconomic Report （2017-2018）

Leaving year 2017 China＇s macroeconomy is continuously characterized by unbalanced and inadequate development. Whereas some aggregate indicators have shown improvement over the year, the cumulative growth rates in consumption and fixed asset investment have continued theirdownward trajectories. Worsening income inequality and resource misallocations, both between secondary and tertiary industries, and within the latter, pose serious challenges, let alone the systemic risk associated with the flourishing shadow banking system, rapid credit growth and debt overhang that weigh on the Chinese economy like the Sword of Damocles. This summary report highlights both the status quo and the consequences of the unbalanced and inadequate development embodied in China＇s persistently distorted economic structure, and the role of deepening reforms of the institutions and governance in resolving the problems. Our analyses based on IAR-CMM model provide a unified framework for addressing China＇s short-, medium-, and long-term issues ir~ an internally coherent manner. Looking into year 2018, our benchmark projection of real GDP growth rate is 6.7% （6.41% using more reliable rather than the official data）. Alternative scenario analyses and policy simulations are conducted to reflect various aspects of the economic challenges in the short to long runs. Through the lens of these analyses we conclude that rule-of-law based and market-oriented structural reforms should continue to hold a center stage in China＇s transition from a phase of high-speed but unbalanced growth, to a stage of balanced and adequate high-quality development.

Promote Competitive Neutrality to Facilitate China’s Economic Development:Outlook,Policy Simulations,and Reform Implementation-A Summary of the Annual SUFE Macroeconomic Report(2019-2020)

Twenty nineteen(2019)marked another year of lethargic growth in the Chinese economy amidst escalated internal and external complexities.Internally,the country's macroeconomic landscape was overcast continuously by fallen consumption growth,plunged growth in manufacturing investment,rapid accumulation of household debt,risen income inequality,and the overhang of local government debt.The nation's external conditions did not fare any better,with drastically declined growth in imports and exports,continued trade tensions with the US,and weakened external demand.Based on the IAR-CMM model,which takes account of both cyclical and secular factors,the baseline real GDP growth rate is projected to be 6.0%in 2020(5.9%using more reliable rather than the official data),with a downside risk.Alternative scenario analyses and policy simulations are conducted,in addition to the benchmark forecast,to reflect the influences of various internal and external uncertainties.The findings emanated from these analyses lead us to stress the importance and urgency of deepening reform to achieve competitive neutrality for China’s transformation into a phase with sustainable and high-quality development.

京津冀高等教育协同发展政策分析与优化

京津冀协同发展于2014年上升为国家战略,高等教育协同发展作为重要组成部分是经济社会发展的重要战略支撑力量。由于协同发展通过三地政府主导,实现了一些资源共享与交流,但面临着协同政策缺位和衔接不畅、体制机制掣肘与发展路径不明确,合作成效明显滞后于其他领域,对区域服务支撑能力没有充分发挥。回溯十多年来的政策实践,探索京津冀高等教育协同发展政策优化依据、优化方向及政策优化路径,为京津冀高等教育协同发展政策执行,提供保障和决策依据。

城镇职工基本医疗保险制度改革受益归宿分析

我国于2021年4月发布了关于城镇职工基本医疗保险制度改革的指导意见。为了探究此次改革的具体受益情况,在赋予城镇职工基本医疗保险的个人账户资金私人属性的基础上,采用模拟分析的方法,对不同收入阶层、参保群体在改革前后的自费负担和自费负担变化幅度进行测算。研究表明:城镇职工基本医疗保险制度改革增加了患病参保群体的受益程度,减轻了自费负担;在不同报销金额、起付线和报销比例的条件下,收入越低的参保群体,其受益增加程度越大;同一假设条件下的在职职工与退休人员,后者在改革中的受益略高于前者。基于结论提出完善城镇职工基本医疗保险缴费、报销环节设计、进一步扩大个账使用范围以及简化家庭共济流程等相关建议。

Simulation-based optimization of control policy on multi-echelon inventory system for fresh agricultural products

As fresh agricultural products are perishable and vulnerable,reducing inventory cost is a strategic target for supply chain enterprises.How to design a reliable multi-echelon inventory control policy is still a great challenge.Therefore,the inventory cost of a three-level fresh agricultural products inventory system was firstly mathematically analyzed.Then,the simulation-based optimization model of the multi-echelon inventory system for fresh agricultural products was proposed by using the Flexsim simulation software and the improved particle swarm optimization algorithm.Finally,the multi-echelon inventory system is simulated based on a large number of survey data.Simulation results demonstrate that the proposed simulation-based optimization model of multi-echelon inventory system for fresh agricultural products can provide decision-making and technical support for the formulation of inventory control policy,and also it shows that the modeling of system simulation is an effective method to solve the problem of complex system.

基于储能技术的电力系统调度方法

文章针对储能参与电力调度优化问题,探讨了不同类型的优化求解方法,包括确定性优化方法、随机优化方法和智能优化方法。通过算例分析,验证了基于储能的电力调度模型的有效性和优越性。相比传统调度方法,储能的参与可显著提升系统经济性、可再生能源消纳水平和电网灵活性。为推动储能参与电力调度,文章提出了加大储能技术研发投入、完善电价机制和补贴政策、建立健全行业标准和规范等政策建议,为促进储能产业发展和电力系统低碳转型提供参考。

基于多目标优化的采煤机截割最优运动参数匹配策略

为避免采煤机电机过载损伤,使其持续可靠高效运行,提出一种基于多目标优化的采煤机截割最优运动学参数匹配控制策略,根据采煤机滚筒的生产率和块煤率等性能指标建立数学模型,构建总的目标函数,采用模拟退火的粒子群算法对其进行寻优,通过构建最优运动学参数匹配模块,仿真分析采煤机截割-牵引协同控制系统。结果表明,与传统采煤机控制方法相比,系统能随着实时工况的变化较好地跟踪最优牵引电机转速和滚筒转速,采煤机生产率降低了3.2%,但块煤率提高了138.5%,截割比能耗总体降低了30.8%,装煤率提高了40%,采煤机的综合性能指标达到最优。

基于裁剪优化和策略指导的近端策略优化算法

针对近端策略优化(PPO)算法难以严格约束新旧策略的差异和探索与利用效率较低这2个问题,提出一种基于裁剪优化和策略指导的PPO(COAPG-PPO)算法。首先,通过分析PPO的裁剪机制,设计基于Wasserstein距离的信任域裁剪方案,加强对新旧策略差异的约束;其次,在策略更新过程中,融入模拟退火和贪心算法的思想,提升算法的探索效率和学习速度。为了验证所提算法的有效性,使用MuJoCo测试基准对COAPG-PPO与CO-PPO(PPO based on Clipping Optimization)、PPO-CMA(PPO with Covariance Matrix Adaptation)、TR-PPO-RB(Trust Region-based PPO with RollBack)和PPO算法进行对比实验。实验结果表明,COAPG-PPO算法在大多数环境中具有更严格的约束能力、更高的探索和利用效率,以及更高的奖励值。

科研经费“包干制”政策的推进特点、实施困境与优化路径

“包干制”试点是科研经费管理“放管服”改革的重要内容。科研经费“包干制”政策核心是赋予科研团队更大的经费使用自主权,简化经费管理流程,以激发科研人员的创新活力和提高科研效率。为进一步识别“包干制”政策优化实施的路径,通过剖析国家、地方政府、高校不同层面在科研经费“包干制”试点改革中的政策推进举措,提炼出科研经费“包干制”政策具有的共性特点。在深入探究目前科研经费“包干制”政策在实施过程面临的政策解读歧义、管理服务滞后、群体认知差异、配套制度欠缺的困境基础上,借鉴美国国家实验室、霍华德·休斯医学研究院、美国国家卫生研究院的科研经费包干管理模式和实践经验,认为试点政策有效执行还需要采取精准施策、柔性化管理、完善激励监督机制等措施,保障科研经费管理改革到位,进一步激发科研人员活力。由此,从精准施策、优化制度,以人为本、激发动力,营造环境、强化监督3个方面提出了政策优化路径。

高等教育综合改革公共政策评估及优化研究

近年来,高等教育综合改革成为高等教育顺应经济新常态、助推高等教育更好发展、更好适应新时代的战略选择。研究相关支持政策的发展现状能够更精确地找到改革中存在的问题,从而对其发展路径进行优化。从国家政策和地方政策两个视域出发,地方视域下选取较为发达的东部地区为代表,基于对近十年国家及东部地区各省市颁布的高等教育综合改革政策出台情况的全面分析,找寻其中存在的问题与不足,并重点针对高等教育综合改革政策体系中存在的问题进行优化,以期满足当前高等教育综合改革工作的需求,以政策创新促进高等教育工作的未来发展。

响应曲面法优化甲烷水蒸气重整制氢工况参数

基于Chemkin的蜂窝整体式反应器计算甲烷水蒸气重整中的甲烷转化率和氢气产率,得到不同工况参数(反应器温度、水蒸气与甲烷的摩尔比(水/碳比)和压力)对甲烷转化率和氢气产率的影响。采用响应曲面法以及Box-Behnken-Design模型对不同工况参数进行优化,建立以氢气产率为响应目标的响应模型。结果表明,水/碳比和反应器温度对氢气产率的影响最为显著。当反应器温度为1079.65 K、水/碳比为3.94、压力为0.11 MPa时,模拟3次的平均氢气产率为80.58%。采用化学反应过程仿真与数值结果预测相结合的方法,显著减少了仿真时间,提高了计算效率和精度。

催化重汽油作原料增产芳烃加工路线的可行性

为了实现减油增化、提高化工产品的附加值,浙江石油化工有限公司利用Petro-SIM流程模拟软件对40 Mt/a炼化一体化项目的催化裂化(FCC)装置、加氢预处理装置、加氢脱硫装置、加氢精制装置、连续催化重整(CCR)装置、芳烃联合装置的工艺生产路线进行了联合模拟与优化,提出了催化重汽油作原料增产芳烃的优化加工路线,并验证了其可行性。结果表明:首先调整FCC装置分馏塔操作参数,以控制催化汽油馏分的终馏点不超过175℃,接着经过加氢预处理装置分馏塔的处理之后,将85~175℃馏分的催化重汽油送入重石脑油加氢预处理装置加工,所得精制重石脑油进入CCR装置,最后C≥6重整生成油进入芳烃联合装置便可生产苯、对二甲苯(PX);当重石脑油加氢预处理装置掺炼质量分数13%的催化重汽油后,精制重石脑油芳潜质量分数提高了6.7个百分点,C≥6重整生成油的链烷烃质量分数下降了1.1个百分点,而其芳烃质量分数提高了1.2个百分点;采用上述优化加工路线后,共加工催化重汽油19.64万t/a,增产的苯、PX分别为2.86,9.45万t/a。

政府规划约束下的城市空间增长多智能体模拟模型

构建政府规划约束下的包含多种类型智能体和环境因素的城市空间增长多智能体模拟模型,通过居民、开发商和政府三类智能体之间以及智能体与环境之间的相互作用模拟了城市空间增长情况。模型将城市建设用地规划区纳入政府的土地利用政策,探讨了政府规划因素对城市建设用地增长的影响,并根据土地集约利用的原则对模拟结果进行了优化。在Repast和ArcGIS的实验环境下,以南京市中心城区(长江以南)为研究区设置了四组土地利用情景,模拟了2001-2007年研究区的城市建设用地增长情况,对比不同情景下模型的模拟精度,说明正确合理的政府规划引导对城市空间增长的重要作用以及对模拟结果进行优化的必要性。该模型有助于揭示城市空间增长机制,为政府宏观调控政策和规划制定提供参考。

基于Ventsim的大型矿井复杂通风系统优化

针对某大型矿井复杂通风系统存在的通风阻力过大、工作面接替时风量供应不足的现状,借助于Ventsim仿真系统,分析找出了矿井通风系统存在的主要问题,并提出3种优化改造方案。综合考虑技术可行性、经济合理性、安全可靠性等因素,确定了方案Ⅲ作为通风系统优化改造的最佳方案。