Optimum design of integrated liquid recovery plants by variable population size genetic algorithm

Increase in the price of energy sources as well as economic problems have caused cryogenic natural gas plants to become more complex and efficient. After selecting the process configuration, the flow rate, pressure, and temperature of the process fluid streams are determining factors which should be tuned in order to find the optimum condition. Products specification and operating costs of the plant are two significant parameters which should be considered in an optimal design. Moreover, process design limitations contribute to the problem being more difficult. This paper shows how the optimal operating point in an integrated NGL recovery plant can be found through solving a complex constrained optimization problem. A Variable Population size Genetic Algorithm (VPGA) was used for optimization. As well, the role of VPGA algorithm parameters in solving the process design problems is investigated in this study. The analysis showed that the VPGA method has better performance compared to the general GA methods. The plant‐wide net profit increases 12493360 $/year only by changing the selected operating conditions to its optimal value.     

海上固定生产平台消防泵数量配置探讨

消防泵设计是海上固定平台设计的重要组成部分。结合规范标准的要求,对海上固定生产平台不同数量的消防泵设计方案进行探讨,分析其优缺点以及适合使用的情况,给出了各种不同设计方案应该考虑的因素。并结合南海海域某固定生产平台的设计实例,对不同数量的消防泵配置进行了分析。     

Development of an optimal multifloor layout model for the generic liquefied natural gas liquefaction process

Liquefied natural gas (LNG) is attracting significant interest as a clean energy alternative to other fossil fuels, mainly for its ease of transport and low carbon dioxide emission. As worldwide demand for LNG consumption has increased, liquefied natural gas floating, production, storage, and offloading (LNG-FPSO) operations have been studied for offshore applications. In particular, the LNG-FPSO topside process systems are located in limited areas. Therefore, the process plant layout of the LNG-FPSO topside systems will be optimized to reduce the area cost occupied by the topside equipment, and this process plant layout will be designed as a multifloor concept. We describe an optimal layout for a generic offshore LNG liquefaction process operated by the dual mixed refrigerant (DMR) cycle. To optimize the multifloor layout for the DMR liquefaction cycle process, an optimization was performed by dividing it into first and the second cycles. A mathematical model of the multifloor layout problem based on these two cycles was formulated, and an optimal multifloor layout was determined by mixed integer linear programming. The mathematical model of the first cycle consists of 725 continuous variables, 198 equality constraints, and 1,107 inequality constraints. The mathematical model of the second cycle consists of 1,291 continuous variables, 286 equality constraints, and 2,327 inequality constraints. The minimization of the total layout cost was defined as an objective function. The proposed model was applied to DMR liquefaction cycle process to determine the optimal multifloor layout.     

浅谈海上采油平台防腐加工设计

海洋环境对钢材腐蚀严重,防腐设计和施工对海洋环境中钢构筑物的安全和寿命非常重要。介绍了海上采油平台建造中防腐涂装加工设计的基本内容和流程,并提出了如何做好防腐涂装加工设计的建议。     

海洋油气平台风险评估系统的研究进展

随着远洋采油等工程的发展,海洋油气平台的风险评估越来越受到各国的重视。综述了海洋油气平台风险评估的必要性、基于事件树分析方法的评估过程和对风险的容忍度原则,阐述了其在各国的发展状况和地位,并对其今后的发展做了展望。     

能量集成常减压系统的简捷模型及优化

针对常减压装置,提出基于Fenske-Underwood-Gilliland方程和焓衡算的简捷模型对现有的常减压系统复杂塔进行操作型计算和优化,并利用夹点分析确定系统的热回收目标。以常减压系统的年净利润最大为目标,同时考虑系统的产品收益和能量集成,建立了基于PSO随机粒子群算法的优化方法。以现有的常减压装置为算例,得到了年净利润最大条件下的各工艺参数。通过与严格模拟对比,表明常减压系统简捷模型能够得到较准确的计算结果。     

Process design for offshore oil and gas production in cold ocean environment

Many considerations influence the design of offshore oil and gas processing facilities such as type of platform, weight and space limitations, environmental conditions, government regulations, drilling support, enhanced recovery, and logistics of supply and market factors. Some of these factors have major impacts on the design and make offshore facilities different from those on land. This paper discusses some typical case scenarios with particular emphasis on processing crude oil in a cold ocean environment such as the Grand Banks off Newfoundland or Beaufort Sea. It describes certain basic requirements for the process design on offshore platforms. Every design is unique for its particular situation.     

设计余量对运行优化和化学过程控制性能的影响简

Operation optimization is an effective method to explore potential economic benefits for existing plants. The m.aximum potential benefit from operationoptimization is determined by the distances between current operating point and process constraints, which is related to the margins of design variables. Because of various ciisturbances in chemical processes, some distances must be reserved for fluctuations of process variables and the optimum operating point is not on some process constraints. Thus the benefit of steady-state optimization can not be fully achied（ed while that of dynamic optimization can be really achieved. In this study, the steady-state optimizationand dynamic optimization are used, and the potential benefit-is divided into achievable benefit for profit and unachievable benefit for control. The fluid catalytic cracking unit （FCCU） is used for case study. With the analysis on how the margins of design variables influence the economic benefit and control performance, the bottlenecks of process design are found and appropriate control structure can be selected.     

E3 Analysis for Crude and Vacuum Distillation System

Crude oil blending is a very common practice in petroleum refineries, where the main focus is to minimize the total purchase cost of crude oils under specified blending oil properties. Crude oil blending actually has significant impacts on energy consumption from heating furnaces during crude oil processing. Conceivably, furnace energy consumption from burning fuels such as natural gas, fuel oil, or propane causes huge amounts of CO₂ emissions. In this paper, a methodology framework for crude oil blending and processing with simultaneous consideration of energy, emission, and economic profit (E3) is developed. It includes four stages of work: steady‐state modeling, heating energy consumption calculation, emission model development, and economic evaluation. With Aspen HYSYS simulation, the developed methodology provides a quantitative support for refinery to identify an optimal E3 operating strategy. A case study is implemented to demonstrate the efficacy of this methodology.     

基于多策略集成优化算法的己烷油精馏过程3E多目标优化

己烷油精馏工序是溶剂油生产过程的重要环节,但其伴随着高能耗和高排放。因此,己烷油精馏工序的能量、经济和环境（3E）多目标优化对于溶剂油工业的可持续发展具有重要意义。针对传统非支配排序遗传算法（NSGA-Ⅱ）收敛速度慢、易陷入局部最优等问题,本文提出了一种改进的基于多策略集成的多目标遗传算法（MENSGA-Ⅱ）。该算法发展了一种基于邻域的引导策略,以增强算法的搜索能力进而加快收敛速度;同时引入随机极限游走策略以维持算法所获得解集的分布性。将MENSGA-Ⅱ应用于典型的测试函数和实际的己烷油精馏过程,结果表明,该算法在鲁棒性、收敛速度和解集分布性上具有优越性。与实际运行工况相比,典型优化工况下精馏系统年度毛利润可提升4.99×10⁵USD/a,能源消耗和CO₂排放可分别减少5.09×10²kW/a和4.82×10²kg/a。     

Mini-hydrocyclones application in the reduction of the total oil-grease (TOG) in a prepared sample of produced water

The process of de-oiling produced water from offshore oil fields was evaluated using hydrocyclones. An experimental design was employed and the results were used to create an empirical model that describes the reduced separation efficiency as a function of different concentrations of infeed and the pressure drop. A study was made of the procedure for preparing the oil-water emulsions used here in order to reproduce the TOG of the produced water generated in oil field. A procedure to verify the operation of these devices demonstrated that six hydrocyclones operating in tandem can attain the legally acceptable concentration of oil in the treated effluent.     

Multi-model based process condition monitoring of offshore oil and gas production process

Offshore oil and gas production platforms are uniquely hazardous in which the operating personnel have to work in a perilous environment surrounded by extremely flammable hydrocarbons. A failure in an equipment could quickly propagate to others resulting in leaks, fires and explosions, causing loss of life, capital invested and production downtime. A method for preventing such accidents is to deploy intelligent monitoring tools which continuously supervise the process and the health of equipments to provide context-specific decision support to operators during safety-critical situations. Such an intelligent system, which is condition driven is developed and described in this paper. Since relevant process data is unavailable in the literature, a dynamic model of an offshore oil and gas production platform was developed using gPROMS and data to reflect operating conditions under normal, fault conditions and maintenance activities were simulated. The different maintenance activities and normal conditions are explicitly considered as separate states of the process. The simulated data are then used to train principal component analysis monitoring models for each of these states. Online fault detection and identification are performed by identifying the operating state in real-time and triggering the respective model. In this paper, the dynamic model and the condition monitoring system are described.     

Discrete-time contraction constrained nonlinear model predictive control using graph-based geodesic computation

Modern chemical processes need to operate around time-varying operating conditions to optimize plant economy, in response to dynamic supply chains (e.g., time-varying specifications of product and energy costs). As such, the process control system needs to handle a wide range of operating conditions whilst optimizing system performance and ensuring stability during transitions. This article presents a reference-flexible nonlinear model predictive control approach using contraction based constraints. Firstly, a contraction condition that ensures convergence to any feasible state trajectories or setpoints is constructed. This condition is then imposed as a constraint on the optimization problem for model predictive control with a general (typically economic) cost function, utilizing Riemannian weighted graphs and shortest path techniques. The result is a reference flexible and fast optimal controller that can trade-off between the rate of target trajectory convergence and economic benefit (away from the desired process objective). The proposed approach is illustrated by a simulation study on a CSTR control problem.     

Simulation of catalyst loss from an industrial fluidized bed reactor on the basis of labscale attrition tests

Attrition of catalyst represents a significant economic penalty due to the necessity to make-up the losses on a continual basis. Designing fluidized bed systems to minimize attrition may sacrifice gas-solid contact efficiency that requires pressure to distribute gases in process vessels uniformly. In this paper, the attrition performance of DuPont's vanadium pyrophosphate oxide catalyst (VPP) used in their commercial Circulating Fluidized Bed (CFB) process to convert n-butane to maleic anhydride has been examined. The analysis is based on simulating the commercial conditions in the individual vessels combined with the physical characteristics of the catalyst determined in the laboratory. The comparison of the catalyst loss rate measured in the industrial plant and the simulation results indicates that the measured values are below the values predicted by the simulation. However, the relative change in the catalyst loss rate with operating time is well described. The simulation allows the quantification of the attrition sources in the process. The simulation results revealed that in the present case over 60% of the catalyst loss originates from attrition in the fluidized beds, whereas only 16% originates from attrition in the cyclones. The simulation is an appropriate tool to investigate the influence of parameter changes. Using the simulation the design parameters and operating conditions can be optimized to minimize the catalyst loss rate in the industrial plant.     

Fresh water by reverse osmosis based desalination: simulation and optimisation

The reverse osmosis (RO) desalination process to make fresh water from seawater has been studied here. First, a model for the process is developed. Sensitivity of different operating parameters (feed flow rate, feed pressure) and design parameters (internal diameter, total number of tubes) on the recovery ratio are studied via repetitive simulation. Finally, an optimisation framework for the process is developed so as to maximize the recovery ratio or a profit function using different energy recovery devices, subjectto general constraints. The optimal operating parameters (feed flow rate, feed pressure) and design parameters (internal diameter, total number of tubes) are determined by solving the optimisation problem using an efficient successive quadratic programming (SQP) based method. The optimal values for the decision variables depend on the constraints introduced, and are also sensitive to variations in water and energy prices, as well as feed concentration. The use ofthe emerging energy recovery devices is widely justified, reporting much higher reductions in operating costs than the traditional technology used for this purpose. Using a pressure exchanger device, it is possible to reduce energy consumption by up to 50%.     

石灰法单塔脱硫系统数值模拟

通过对石灰法烟气脱硫系统工艺进行研究,以Aspen Plus模拟软件为平台,对单塔系统的化工过程进行模拟,输入热烟气的热力学参数和操作条件,采用控制变量法,模拟塔内发生的酸碱中和、吸收和氧化反应过程。通过模拟入口烟气流量、SO_2浓度、钙硫比等烟气参数变化趋势,进一步分析各因素对脱硫效率的影响,以期对系统的优化设计提供参考。根据实际装置的运行情况,优化现有的设备和流程,对进一步完善和改进脱硫工艺有着重大的理论意义和实用价值。     

考虑碳排放量的穿梭油轮路径绿色调度优化

海上穿梭油轮在深远海及海上边际油田的石油外输系统中担任着重要角色,其路径规划决定着整个石油外输系统运输效率.海上原油运输方式占整个原油运量的80％,为提高原油公司市场竞争力、降低其海运成本,对穿梭油轮船队的合理设计及路径的调度优化至关重要.近年来,学者更注重于研究建立一种与环境共生的、能促进经济和消费生活健康发展的绿色...     

绥中处理厂锅炉燃料气流程设计

绥中终端原油处理厂现在使用的热介质加热锅炉所用燃料都是旅大油田的原油,而旅大10-1油田CEP平台生产的富余伴生气确被放到火炬白白烧掉,不仅浪费而且污染环境。本文通过分析海上平台和处理厂的流程,以及平台到处理厂的输油海管的情况,提出了如何把伴生气送到终端,并处理成满足锅炉使用的燃料气的流程方案。该方案如果实施不仅经济效益显著,而且符合国家提倡的节能环保的政策。     

面向海洋工程的超重力过程强化技术及应用

以旋转填料床（rotating packed bed, RPB）为核心装备的超重力技术是典型的化工过程强化技术之一,由于具有体积小、传质及分离效率高的优点,已被成功应用于海洋平台的化工过程中。介绍了超重力技术的核心装备结构及原理,回顾了针对超重力技术的各项基础实验研究、数学模型化和CFD模拟方面的工作,这些工作为超重力技术的工业应用提供了很好的理论支持。最后介绍了近年来超重力技术在海洋平台油气生产中天然气脱水、脱硫及注入水脱氧过程的工业应用。     

基于FLUENT的海上平台天然气储罐泄漏扩散研究

针对海上石油平台天然气储罐泄漏扩散问题,基于计算流体动力学软件FLUENT,参照某海洋平台,建立海上平台的二维模型。模拟得到不同风速、泄漏孔径和泄漏速度条件下天然气在海上平台的泄漏扩散分布规律,并根据天然气5%~15%的爆炸极限模拟出天然气泄漏后的危险区域。模拟结果表明不同风速、泄漏孔径和泄漏速度与天然气泄漏扩散之间的规律并以此预测天然气泄漏扩散危险区域。为此类事故的预防、控制以及海上平台人员应急逃生方面均提供了参考。