常规及创新高压凝液回收流程对比

塔里木盆地地区的英买、迪那等大型高压凝析气田目前仅对原料天然气进行了烃水露点控制,重烃回收率低,经济效益没有实现最大化,对此类气田进行凝液回收可显著提升气田的经济效益。现今适用于高压天然气凝液回收的流程主要为HPA（high pressure absorber）流程,本文在HPA流程基础上提出两种改进流程,即改进Ⅰ型流程和改进Ⅱ型流程。并通过SQP（sequential quadratic programming）算法以单位能耗最低为目标函数对3种流程进行操作参数优化, 并通过能耗分析表明：3种流程具有不同原料气贫富和压力适应范围,在贫气条件下,原料气压力在7000~8000kPa范围内,改进Ⅰ型比HPA流程更节能,而当原料气压力高于7500kPa时,改进Ⅱ型流程能耗开始低于前两者,且随原料气压力增加,节能效果更加明显。而对于富气,改进Ⅱ型流程能耗最高,改进Ⅰ型与HPA流程区别不明显。     

Techno-economic analysis of potential natural gas liquid (NGL) recovery processes under variations of feed compositions

This paper presents the different process schemes used for known NGL recovery methods with respect to their economic performance. The original turbo-expander (ISS) was considered as base case plant. The GSP, CRR and RSV process schemes focus on improvement at the top of the demethanizer column. The IPSI-1 and IPSI-2 schemes focus on the bottom of the demethanizer column. All the process schemes were initially built using Aspen HYSYS with a common set of operating criteria. Numerous simulation runs were made by taking various typical feed compositions classified as lean and rich. The economic assessment for each process scheme was later made by considering the capital cost, operating cost and profitability analysis. Results showed that the IPSI-1 process scheme gives the best economic performance with lowest TAC and payback time compared to the other process schemes. On the other hand, the RSV process gives higher TAC and payback time compared to others.     

利用液化天然气冷能的朗肯循环与联合法发电系统流程的工艺模拟与对比分析

液化天然气(LNG)在再气化过程中具有巨大的冷能利用价值。目前回收LNG冷能的诸多方法中LNG冷能发电是最有可能大规模利用的方式,同时也是技术较为成熟的方法。在保证天然气入网压力及膨胀机最大承压的条件下,通过HYSYS流程模拟软件对以丙烷为工质的朗肯循环、天然气直接膨胀与朗肯循环相结合的联合循环进行流程模拟,并根据模拟得到的过程参数和输出功进行对比分析,总结了两种循环的特点和发电收益。如果以年蒸发量为150万吨、年工作小时为8000 h的LNG接收站作为分析的基础,并以工业用电价格0.55元·(kW·h)^-1计算,联合法的年发电收益将比朗肯循环法多487万元,以此可以作为两种循环流程经济性分析的基础,为流程全面的经济性分析提供可靠的依据。     

集成NGL回收的新型天然气液化系统AP-XTM的概念设计与模拟分析

为提高液化天然气能量集成与设备共用水平,提出了一种基于大型AP-X^TM液化流程，综合气体过冷技术（GSP）的集成NGL（天然气凝液）回收工艺的天然气液化系统的概念设计。基于化工流程模拟软件Aspen HYSYS进行模拟和分析，将集成工艺多流股换热器性能、全流程的单位功耗和乙烷回收率作为衡量系统性能的三项指标。模拟和分析的结果表明，集成NGL回收的AP-X^TM液化工艺单位功耗降低至0.45 kW·h·(kg LNG)^-1，较单产系统能耗降低了6%，同时乙烷回收率达到93%，实现了NGL的高效分离。通过热力学分析、?分析和经济性分析得出本设计流程具有较高的性能和经济价值，可为天然气液化工艺的集成设计和技术改造提供指导借鉴。     

液化天然气(LNG)接收站节能再冷凝器的研究与设计

随着天然气在我国能源结构中比例的上升,液化天然气(LNG)接收站如雨后春笋,发展非常快。而在LNG接收站中,再冷凝器是一个核心工艺设备,工艺操作参数及结构尺寸的是否合理,对接收站的投资和运营成本影响很大,而且也是接收站能否长期稳定操作的关键。     

A survey on applications of optimization-based integrating process design and control for chemical processes

Process design and control are closely related to each other in chemical engineering activities. Traditionally, process design and control system design are carried out in sequence. However, the integration of process design and control (IPDC) can bring greater economic benefits and process dynamic performance than traditional sequential design methods. This is true, particularly for modern chemical processes, in which various process units become more interacting and compact owing to the widespread use of heat integration and recycled streams, and the resulted impacts between process design and control begin to significantly influence both the capital and operational costs. Recently, considerable studies about the IPDC for chemical processes have been reported in published literature. The purpose of the paper is to survey the applications of optimization-based integrating process design and control for chemical processes. Firstly, attention has been focused on the applications of IPDC to different process units, for example, chemical reactors and separation columns. Then, the survey is extended to the applications of IPDC to plant-wide chemical processes. Finally, the future research challenges in the application of IPDC to chemical processes have been briefly discussed.     

焦炉气联产LNG、纯氢气和甲醇工艺开发

介绍了四川天一科技股份有限公司开发的焦炉气联产液化合成天然气、纯氢气和甲醇的新工艺,此工艺具有原料损耗较少、各系统技术成熟简单、产品结构多元化等优势;并介绍了一种适用于此联产工艺的合成甲烷催化剂。     

A novel hybrid process design for efficient recovery of hydrophilic ionic liquids from dilute aqueous solutions

Ionic liquids (ILs) have received much attention in both academia and industries due to their superior performance in many applications. Efficient recovery/recycling of ILs from their dilute aqueous solutions is essential for the acceptance and implementation of many IL-based technologies by industry. In this work, a practical and cost-effective hybrid process design method that combines aqueous two-phase extraction, membrane separation, and distillation operating at their highest efficiencies is proposed for the recovery of hydrophilic ILs from dilute aqueous solutions. The application of this hybrid process design method is illustrated through case studies of recovering two hydrophilic ILs, n-butylpyridinium trifluoromethanesulfonate ([C₄Py][TfO]) (CAS number: 390423-43-5) and 1-butyl-3-methylimidazolium chloride ([C₄mIm][Cl]) (CAS number: 79917-90-1), from their dilute aqueous solutions. For the recovery of 10 wt.% [C₄Py][TfO] from aqueous solution, the hybrid process using (NH₄)₂SO₄ as the salting-out agent could reduce the total annual cost (TAC) and energy consumption by 57% and 91%, respectively, compared with the pure distillation processes. In the case of recovering 10 wt.% [C₄mIm][Cl] from aqueous solution, the reduction in TAC and energy savings of the hybrid process with salting-out agent (NH₄)₂SO₃ could reach 49% and 87%, respectively, compared with the pure distillation process. Furthermore, uncertainty analysis through Monte Carlo simulations show that the proposed hybrid process design is more robust to uncertainties in energy prices and other material (e.g., equipment and solvent) costs.     

混合分离过程的有序设计框架

The design of optimal separation flow sheets for multi-component mixtures is still not a solved problem This is especially the case when non-ideal or azeotropic mixtures or hybrid separation processes are considered. We review recent developments in this field and present a systematic framework for the design of separation flow sheets. This framework proposes a three-step approach. In the first step different flow sheets are generated. In the second step these alternative flow sheet structures are evaluated with shortcut methods. In the third step a rigorous mixed-integer nonlinear programming （MINLP） optimization of the entire flow sheet is executed to determine the best alternative. Since a number of alternative flow sheets have already been eliminated, only a few optimization runs are necessary in this final step. The whole framework thus allows the systematic generation and evaluation of separation processes and is illustrated with the case study of the separation of ethanol and water.     

3种氯乙烯精馏尾气回收工艺的分析比较

介绍了聚氯乙烯树脂生产过程中氯乙烯精馏尾气产生的工艺,并对使用的3种氯乙烯精馏尾气回收工艺进行了分析比较.     

一种新的利用LNG冷能的回收油田伴生气凝液的工艺

A novel process to recovery natural gas liquids from oil field associated gas with liquefied natural gas (LNG)cryogenic energy utilization is proposed.Compared to the current electric refrigeration process,the proposed process uses the cryogenic energy of LNG and saves 62.6%of electricity.The proposed process recovers ethane, liquid petroleum gas(propane and butane)and heavier hydrocarbons,with total recovery rate of natural gas liquids up to 96.8%.In this paper,exergy analysis and the energy utilization diagram method(EUD)are used to assess the new process and identify the key operation units with large exergy loss.The results show that exergy efficiency of the new process is 44.3%.Compared to the electric refrigeration process,exergy efficiency of the new process is improved by 16%.The proposed process has been applied and implemented in a conceptual design scheme of the cryogenic energy utilization for a 300 million tons/yr LNG receiving terminal in a northern Chinese harbor.     

加油站油气综合治理技术及工艺设计

本文简述了加油站油气回收的重要意义,分析了国内外加油站油气排放治理现状,详细介绍油气前处理和后出理的各自重要性。提出了加油站整套油气回收工艺的设计方案并应用于实际,指出了在实施油气回收系统时应注意的问题。结果表明加油站应用油气回收技术成效明显,具有环保、节能、安全多重功效。     

A power plant for integrated waste energy recovery from liquid air energy storage and liquefied natural gas

Liquefied natural gas(LNG)is regarded as one of the cleanest fossil fuel and has experienced significant developments in recent years.The liquefaction process of natural gas is energy-intensive,while the regasification of LNG gives out a huge amount of waste energy since plenty of high grade cold energy(-160℃)from LNG is released to sea water directly in most cases,and also sometimes LNG is burned for regasification.On the other hand,liquid air energy storage(LAES)is an emerging energy storage tech-nology for applications such as peak load shifting of power grids,which generates 30％-40％of compres-sion heat(～200℃).Such heat could lead to energy waste if not recovered and used.The recovery of the compression heat is technically feasible but requires additional capital investment,which may not always be economically attractive.Therefore,we propose a power plant for recovering the waste cryo-genic energy from LNG regasification and compression heat from the LAES.The challenge for such a power plant is the wide working temperature range between the low-temperature exergy source(-160℃)and heat source(～200℃).Nitrogen and argon are proposed as the working fluids to address the challenge.Thermodynamic analyses are carried out and the results show that the power plant could achieve a thermal efficiency of 27％and 19％and an exergy efficiency of 40％and 28％for nitrogen and argon,respectively.Here,with the nitrogen as working fluid undergoes a complete Brayton Cycle,while the argon based power plant goes through a combined Brayton and Rankine Cycle.Besides,the economic analysis shows that the payback period of this proposed system is only 2.2 years,utilizing the excess heat from a 5 MW/40MWh LAES system.The findings suggest that the waste energy based power plant could be co-located with the LNG terminal and LAES plant,providing additional power output and reducing energy waste.     

A methodology for the sustainable design and implementation strategy of CO2 utilization processes

This work presents a systematic methodology that has been developed for the design of sustainable CO₂ utilization processes that can mitigate CO₂ and also guarantee profitability. First, the three-stage methodology, evaluation criteria and applicable tools are described. Especially, the process design and analysis is discussed as only limited amounts of process data is available for determining the optimal processing path and in the third stage the issue of implementation strategy is considered. As examples, two CO₂ utilization methods for methanol production, combined reforming and direct synthesis are considered. Methanol plants employing such methods are developed using synthesis-design and simulation tools and their evaluation indicators are calculated under various implementation strategies. It is demonstrated that integrating or replacing an existing conventional methanol plant by a combined reforming method represents a sustainable solution. Additionally, producing methanol through direct hydrogenation is a promising way to convert CO₂ when cheap H₂ feeds are available.     

Optimal design and operations of supply chain networks for water management in shale gas production: MILFP model and algorithms for the water‐energy nexus

The optimal design and operations of water supply chain networks for shale gas production is addressed. A mixed‐integer linear fractional programming (MILFP) model is developed with the objective to maximize profit per unit freshwater consumption, such that both economic performance and water‐use efficiency are optimized. The model simultaneously accounts for the design and operational decisions for freshwater source selection, multiple transportation modes, and water management options. Water management options include disposal, commercial centralized wastewater treatment, and onsite treatment (filtration, lime softening, thermal distillation). To globally optimize the resulting MILFP problem efficiently, three tailored solution algorithms are presented: a parametric approach, a reformulation‐linearization method, and a novel Branch‐and‐Bound and Charnes–Cooper transformation method. The proposed models and algorithms are illustrated through two case studies based on Marcellus shale play, in which onsite treatment shows its superiority in improving freshwater conservancy, maintaining a stable water flow, and reducing transportation burden. © 2014 American Institute of Chemical Engineers AIChE J, 61: 1184–1208, 2015     

A new method of amine solvent recovery with acid addition for energy reduction in the CO2 absorption process

Chemical absorption/stripping technologies using an amine-based solvent have a lot of advantages for capturing carbon dioxide in post-combustion capture system. However, the higher energy demand for the solvent recovery makes the technology difficult to retrofit to existing plants. To overcome this obstacle, an alternative stripping process using an organic acid was studied to decrease the solubility of carbon dioxide and save the energy demand, but further research is necessary to recover the amine solvent and an organic acid effectively. In this study, a new amine recovery method using an organic acid is proposed and the method suggests a two-step of reaction crystallization process to separate the amine and the acid. This study demonstrates that an amine solvent (monoethanolamine, MEA) and an organic acid (oxalic acid) could be recycled effectively by reaction crystallization experiment. MEA and oxalic acid recovery efficiencies were also obtained using the experimental data in this study. The percentages of MEA recovery and the acid losses were estimated through these data. In addition, the energy demands for two recovery processes were estimated.     

Simultaneous process synthesis and control design under uncertainty: A worst‐case performance approach

A new methodology that includes process synthesis and control structure decisions for the optimal process and control design of dynamic systems under uncertainty is presented. The method integrates dynamic flexibility and dynamic feasibility in a single optimization formulation, thus, reducing the costs to assess the optimal design. A robust stability test is also included in the proposed method to ensure that the optimal design is stable in the presence of magnitude‐bounded perturbations. Since disturbances are treated as stochastic time‐discrete unmeasured inputs, the optimal process synthesis and control design specified by this method remains feasible and stable in the presence of the most critical realizations in the disturbances. The proposed methodology has been applied to simultaneously design and control a system of CSTRs and a ternary distillation column. A study on the computational costs associated with this method is presented and compared to that required by a dynamic optimization‐based scheme. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2497–2514, 2013     

A methodology for simultaneous process and product design in the formulated consumer products industry: The case study of the detergent business

In this work we present a mathematical optimization based methodology for simultaneous formulae and process design in the consumer product business applied to the case of the laundry detergent. The design of a new detergent is formulated as a modified pooling problem including process, performance, processability and environmental constraints. This new features add a number of nonlinearities related to the modeling of the different aspects of the process and customer acceptance. The problem becomes a multiobjective optimization problem that is solved using the ?-constraint method with global optimization techniques to minimize of the environmental impact while minimizing the production cost for a couple of case studies. As future work, further process, product and legal constraints can be added to make the problem more realistic.