Operability and control in process intensification and modular design: Challenges and opportunities

In this article, the importance of considering operability and control criteria in the analysis and design of intensified and modular processes is discussed. We first analyze the impact on operability of key factors including: (i) degrees of freedom, (ii) process constraints, (iii) numbering up vs. scaling up, and (iv) dynamic/periodic operation. Comparative examples are presented to showcase the pros and cons in intensified/modular systems vs. their conventional counterparts from operability and control aspects. Then we look into metrics and tools to address these challenges such as: (i) flexibility analysis, (ii) operability-based design, and (iii) advanced model-based control. Considering different conceptual design stages as synthesis intensification, steady-state design, and dynamic operational optimization, we highlight the need to incorporate different levels of operability considerations. Future research opportunities and perspectives are also identified, particularly emphasizing the importance of a holistic strategy for integrated design, operability, and control of intensified and modular process systems.     

Plantwide operability assessment for nonlinear processes using a microscopic level network analysis

The increase of raw material and energy costs has caused a shift in process design philosophy leading to more complex chemical plants utilising heat integration and material recycles. This warrants plantwide dynamic operability analysis in the process design stage. In our previous work, a networked plantwide operability analysis approach was developed, where the plantwide process is viewed as a network of process units connected via mass and energy flow. Such an analysis is based on the dissipativity of each process unit and the topology of the process network. However, to determine the dissipativity of multivariable nonlinear process units is often extremely difficult. In this work, we take the network approach to a microscopic level and treat each nonlinear multivariable process unit as a network of individual (single state) mass and energy balances (sub-systems). The plantwide process is then viewed as a network of such sub-systems rather than physical process units. The dissipativity of these simple sub-systems can often be determined more easily in comparison to that of multivariable sub-systems. The dissipativity property (in terms of supply rate) of the entire nonlinear process can be parametrised by the dissipativity of individual sub-systems, leading to a cluster of supply rates. The operability of the plantwide nonlinear process can then be determined based on the above parametrised dissipativity which can be much less conservative than existing nonlinear analysis. The effects of interactions caused by the interconnections are considered explicitly based on the network topology. The stability and stabilisability analysis problem is then converted into a feasibility problem with linear matrix inequalities which can be solved numerically. The application of the proposed approach requires successful determination of the dissipativity of nonlinear sub-systems.     

Modern Technology Applied in Advanced BWR (ABWR)

The Advanced Boiling Water Reactor (ABWR) has been developed by an international team of BWR manufacturers to respond to worldwide utility needs in the 1990's. Major objectives of the ABWR program are design simplification; improved safety and reliability; reduced construction, fuel and operating costs; improved maneuverability; and reduced radiation exposure and radwaste. The ABWR is the result of the continuing evolution of the BWR, incorporating state-of-the-art technology and improvements based on worldwide experience, and extensive design and test and development programs. The ABWR incorporates the best proven features from BWR designs in Japan, the United States and Europe. The many new features are seen to provide superiority in terms of performance characteristics and economics relative to current LWR designs. The Tokyo Electric Power Co., Inc. recently announced the selection of General Electric Co., Hitachi, Ltd. and Toshiba Corp. to design and construct two lead Advanced Boiling Water Reactors as Unit 6 and 7 at the Kashiwazaki Kariwa Nuclear Power Station. Construction is scheduled for the early 1990's, and commercial operation planned for 1996 for Unit 6 and 1998 for Unit 7.     

磺化工艺的危险性及可操作性分析

磺化工艺作为国家安全监管总局所列的首批重点监管的危险化工工艺,已经受到政府部门、企业以及设计单位的高度重视。通过对磺化工艺的介绍,阐述如何通过辨识危险因素,确定重大危险源,从而采取相关的应急停车系统,并通过引用HAZOP分析技术来进行危险工艺的安全设计,进而采取合理的事故防范措施。     

化工园区及其生产装置等设施的安全问题探讨

化工园区很多化工生产装置、罐区等集聚在一起,安全问题十分重要,必须有防护措施。介绍了国内外安全评价发展及事故概况。国外强调提高本质安全水平和对人员进行安全文化教育,以防止事故发生和减少损失。现国外已普遍采用危险和可操作性研究(HAZOP)方法进行分析研究并认为其行之有效。最后对安全问题提出几点意见供参考。     

手工焊环工序质量的分析研究

分析了手工制造焊环的工艺流程，根据实测的手工焊环加工工序前后的相关质量特性数据，利用质量分析工具直方图以及工序能力指数分析确定出影响手工焊环质量水平与均匀程度的主要工序并计算出相关工序的工序能力指数，从而得出影响手工焊环质量水平的主要因素，并对手工焊环制造过程中存在的薄弱环节提出了一些有益的改进建议．     

后3G时代LTE异军突起

介绍了下一代无线网络LTE(Long Term Evolution,长期演进)的背景和发展状况.分析了LTE的技术特征,阐述了LTE网络结构与核心技术,并通过与WiFi(WirelessFidelity)及WiMAX(World wide Inter operability for Microwave Access)的各项性能作比较,着重分析了LTE的技术优势.最后,指出了LTE在个人通信市场所面临的应用前景与挑战.     

水性仿古漆——重塑木材自然气质的涂装工艺

水性仿古漆(水性擦拭型着色剂)在水性木器涂料涂装工艺中能塑造出木材自然的纹理气质,可同目前的溶剂型涂料涂装效果相媲美。     

Quality assessment support system and its use in pharmaceutical plant operations

On the basis of the quality by design approach, aggregation of knowledge in process chemistry and manufacturing operations is essential for the continuous development of pharmaceutical products and processes. We develop a model-based framework to describe process chemistry oriented phenomenal sequences leading to quality hazards (process deviation scenario), which should be independent of any specific plant structural information, and manufacturing procedural error oriented event propagations (procedural control scenario), which concern a specific plant structure. We propose a system, Quality-HAZOP, to analyze the scenarios in which manufacturing errors can affect product quality via complex propagation pathways. This system supports bidirectional improvement proposal between recipe scientists and process engineers. This proposal triggers risk information exchange that supports the continuous improvement of the process in life-cycle pharmaceutical development.     

基于未确知的化工系统HAZOP分析

基于传统的HAZOP分析存在量化困难的缺陷,提出未确知数-HAZOP分析模型,该模型不仅解决传统HAZOP分析的存在的问题,还可以根据专家经验程度的不同整合专家给出的原因事件的概率区间值。文章利用该模型对运行过程中的化工装置进行了定性定量的分析。未确知数-HAZOP的分析思想对于进行化工事故预防具有重要的意义。