合成氨和尿素装置仿真培训系统的开发及应用

论述了合成氨和尿素装置仿真培训系统(OTS)开发过程中具体建模的范围以及建模所用方法,其中包括装置各动、静设备模型中用到的方法和装置各个系统物料计算所用到的热力学方法。对已成功开发的OTS模拟器在操作员工的培训、控制系统的校验、操作员工能力的测评以及操作员工技能竞赛等方面的应用进行了介绍,同时也对新建装置在OTS开发过程中经常遇到的问题进行了简要说明。     

Operator training simulator process model implementation of a batch processing unit in a packaged simulation software

In chemical industry, especially in the case of continuous processes, operator training simulators (OTS) are becoming widely used. With the help of these systems several operation and safety issues can be analysed, and the operating staff of the plant can be trained for handling different plant failures. The main part of the OTS is the process model that replaces the real technology. Hence, in control development the simulated process variables are required to be reasonably accurate. The paper presents the structure of the process model of a batch processing unit in UniSim Design, different model constructions of a jacketed batch reactor and the identification of the parameters affecting its hydrodynamic and thermal behaviour. Construction of the process model is the first step in developing the OTS of the pilot plant located in the authors’ laboratory. It can be an effective tool in the development of model-based control systems.     

An overview of the enzyme potential in bioenergy‐producing biorefineries

Biorefineries are considered as an integrative thinking that focuses on the possibility of obtaining as many added‐value products as technically and economically feasible. However, in practice most biorefineries comprise only enzymatic or chemical pretreatment followed by biofuel generation. The drop in oil prices may menace the development of this young industry, as has happened before in history. This has become a fundamental reason for which the biofuel industry should not consider only biofuels production, but enzyme and non‐fuel based chemicals as well. Hence, this work aims at overviewing the most important enzymes involved in biotechnological processes and to describe their role in biorefineries. Bioethanol, biogas and biodiesel biorefineries are overviewed, along with the integrated and industrial types. Finally separation and purification processes in biorefineries are discussed. © 2016 Society of Chemical Industry     

Process synthesis and optimization of biorefinery configurations

Recently, there has been a growing interest in the development of cost‐effective technologies for the production of biofuels. A common approach to biofuel research is to invent or improve a biochemical or thermochemical conversion step. Subsequently, other conversion and separation steps are added to form a complete biorefinery flowsheet. Because this approach is structured around a specific conversion step, it may limit the possibilities of configuring optimal and innovative biorefineries. This article proposes a novel and systematic two‐stage approach to the synthesis and optimization of biorefinery configurations, given available feedstocks and desired products. In the synthesis stage, a systems‐based approach is developed to create a methodical way for synthesizing integrated biorefineries. This method is referred to as “forward‐backward” approach. It involves forward synthesis of biomass to possible intermediates and reverse synthesis starting with the desired products and identifying necessary species and pathways leading to them. In the optimization stage, Bellman's principle of optimality is applied to decompose the optimization problem into subproblems in which an optimal policy of available technologies is determined for every conversion step. An optimization formulation is utilized to determine the optimal configuration based on screening and connecting the optimal policies and generating the biorefinery flowsheet. A case study of alcohol‐producing pathways from lignocellulosic biomass is solved to demonstrate the merits of the proposed approach. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Simulatoren zur Unterstützung der Prozeß- und Betriebsführung

Simulators for support of process and plant management. Process simulators are increasingly used for plant and process operation purposes. These simulators differ from those used in process design in the user interface, which is identical to the usual operator interface of distributed control systems. The progress of the numerical solution parallels the dynamic behaviour of the real process, and not that of the numerical procedure. The simulation-supported tasks of plant and process operation are: education of operators, training and instruction of operators, support of plant operation by interpretion of plant states and transitions and by helping to formulate operating instructions. These tasks, the available simulation concepts and examples are discussed in detail.     

A review of the potential of pretreated solids to improve gas biofuels production in the context of an OFMSW biorefinery

The organic fraction of municipal solid waste (OFMSW), mainly composed of lignocellulosic polymers, is extremely complex. Therefore, it is necessary to apply pretreatments to remove the lignin content and decrease the cellulose crystallinity in order to use the OFMSW for gas biofuels production in the context of biorefineries from waste. This work focused on critically reviewing the conventional pretreatments applied to OFMSW, with the goal of improving the H₂ production, as well as other biofuels in modern biorefineries. There are a wide variety of pretreatments that have successfully been used, mainly alkaline, milling and dilute acid. In addition, some research has focused on the recovery and reutilization of the alkali, acid or solvents after the pretreatment, to be incorporated into new cycles of production, minimizing the environmental impacts. Moreover, it would be necessary to incorporate analytical tools, in order to determine the sustainability of the biorefinery project. It is concluded that waste pretreatments could significantly contribute to increased yields of biogas fuels in organic waste‐based biorefineries. Therefore, establishing preliminary stages for conditioning biomass or wastes is essential to improve the degradation of wastes and bio‐product generation. © 2016 Society of Chemical Industry     

A multiobjective optimization framework for design of integrated biorefineries under uncertainty

A systematic approach for development of a reliable optimization framework to address the optimal design of integrated biorefineries in the face of uncertainty is presented. In the current formulation, a distributed strategy which is composed of different layers including strategic optimization, risk management, detailed mechanistic modeling, and operational level optimization is applied. In the strategic model, a multiobjective stochastic optimization approach is utilized to incorporate the tradeoffs between the cost and the financial risk. Then, Aspen Plus models are built to provide detailed simulation of biorefineries. In the final layer, an evolutionary algorithm is employed to optimize the operating condition. To demonstrate the effectiveness of the framework, a hypothetical case study referring to a multiproduct lignocellulosic biorefinery is utilized. The numerical results reveal the efficacy of the proposed approach; it provides decision makers with a quantitative analysis to determine the optimum capacity plan and operating conditions of the biorefinery. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3208–3222, 2015     

Alternative technologies for biotechnological fuel ethanol manufacturing

The challenges of implementing biorefineries on a global scale include socioeconomic, financial, and technological constraints. In particular, the development of biorefineries is tightly linked to the continued availability of fermentation raw materials. These constraints can be relaxed by the use of diverse raw materials, while advances that confer higher flexibility would enable biotechnological plant managers to swiftly react to volatile markets. In conventional processes, Saccharomyces cerevisiae grows on a relatively limited range of substrates, and produces only a single product—ethanol. Given the observed maturity of the S. cerevisiae fermentation technology, alternatives to baker's yeast may be needed to tip the economic balance in favour of biotechnological ethanol. These alternative fermentation technologies may allow a greater diversity of substrates to be used to produce an individually tailored mix of ethanol and other chemicals. Copyright © 2007 Society of Chemical Industry     

制浆造纸厂实行生物炼制的可行性

生物炼制是解决石化资源紧缺的新途径,而制浆造纸厂是生物炼制技术最容易实现产业化的平台。文章综述了制浆造纸厂中半纤维素、木质素、松节油、妥尔油等废弃生物质进行生物炼制的可行性及存在的问题,并对发展前景作了展望。     

OTS在环氧氯丙烷装置中的应用

研究了操作员仿真培训系统(OTS)在环氧氯丙烷装置中的具体应用。介绍了OTS的基本概念及软硬件组成,对环氧氯丙烷工艺流程进行分析并研究了OTS系统的使用流程,总结了研究的成果在实际生产中所带来的经济和社会效益。     

A shortcut method for the preliminary synthesis of process-technology pathways: An optimization approach and application for the conceptual design of integrated biorefineries

Synthesis and screening of technology alternatives is a key process-development activity in the process industries. Recently, this has become particularly important for the conceptual design of biorefineries. This work introduces a shortcut method for the synthesis and screening of integrated biorefineries. A structural representation (referred to as the chemical species/conversion operator) is introduced. It is used to track individual chemicals while allowing for the processing of multiple chemicals in processing technologies. The representation is used to embed potential configurations of interest. An optimization approach is developed to screen and determine optimum network configurations for various technology pathways using simple data. The solution to the optimization formulation provides a quick and effective method for screening and interconnecting the technological pathways and to distributing the flows over the network. Case studies are solved to illustrate the applicability of the proposed approach.     

Design of integrated biorefineries

The paper outlines a systems approach with capabilities to address common complexities and practicalities in the design of real-life integrated biorefineries. The approach favors a decomposition of the problem into process synthesis, process integration and flowsheeting. The synthesis of paths introduces a graph representation sufficiently generic to model the general problem. Likewise, the development of product portfolios offers a generic cascade representation that combines thermodynamics with mathematical programming. The methodology renders high-throughput capacity and has been exploited to review large combinations of paths through exhaustive screening, subsequently leading to significant savings in capital and operating costs. The paper highlights results from the approach as it has configured the operation and the evolution of existing pilots and demos. The methodology is being extended to address strategic decisions and the better integration of the biorefinery concept. The paper explains limitations and opportunities of existing methods and tools, highlighting the scope for future developments and applications.     

Recent advances in production and biotechnological applications of thermostable and alkaline bacterial lipases

Microbial lipases occupy a vital position with respect to their industrial applications and they are studied extensively. Thermophilic microorganisms are potential sources of thermostable alkaline lipases, which have been isolated from various natural origins. Most lipases can act in a wide range of pH and temperature, though alkaline bacterial lipases are more common. Thermostable alkaline lipases have commercial value and find applications in various industrial and biotechnological sectors such as additives in detergents, additives in food industries, environmental bioremediations and in molecular biology. The latest trend in lipase research is the development of novel and improved lipases through molecular approaches such as directed evolution and exploring natural communities by the metagenomic approach. Therefore, thermostable alkaline lipases are the enzymes of choice for many biotechnologists, microbiologists, biochemists, environmentalists and biochemical engineers. In the present review, we discuss some novel sources along with recent advances in fermentation conditions, substrate conditions and biotechnological applications of thermostable alkaline bacterial lipases. © 2013 Society of Chemical Industry     

Insight into microbial hemicellulases other than xylanases: a review

Hemicellulases responsible for depolymerization of hemicellulose, including α‐glucuronidase, α‐arabinofuranosidase, arabinase, endo‐mannanase, β‐mannosidase, acetyl xylan esterase and feruloyl xylan esterase, were reviewed. They usually exist as multimers with a modified (β/α)₈ Tim barrel fold. In a few cases they possess a substrate binding domain which helps them bind to the substrates bringing efficient hydrolysis. Post‐translational modifications are the major reasons leading to enzyme multiplicities to adapt the heterogeneous nature of hemicellulose. Glycosylation is one of the most important post translational modifications and contributes multiple functions to the protein such as stability, multiplicity and in a few cases enzyme activity. Advances in recombinant DNA technology have made it feasible to clone, improve and functionally express them in various hosts. Hemicellulases are traditionally applied in food, feed, detergent and paper industries, but their applications in hydrolysis of hemicellulose to release sugars is expected to increase, driven by the rapid development of lignocellulose biorefineries. Screening more powerful hemicellulases from nature, mining their coding genes from various sources and engineering them genetically are recommended for broadening their applications. © 2012 Society of Chemical Industry     

Sugarcane bagasse and leaves: foreseeable biomass of biofuel and bio‐products

Sugarcane is among the principal agricultural crops cultivated in tropical countries. The annual world production of sugarcane is ～1.6 billion tons, and it generates ～279 million metric tons (MMT) of biomass residues (bagasse and leaves). Sugarcane residues, particularly sugarcane bagasse (SB) and leaves (SL) have been explored for both biotechnological and non‐biotechnological applications. For the last three decades, SB and SL have been explored for use in lignocellulosic bioconversion, which offers opportunities for the economic utilization of residual substrates in the production of bioethanol and value‐added commercial products such as xylitol, specialty enzymes, organic acids, single‐cell protein, etc. However, there are still major technological and economic challenges to be addressed in the development of bio‐based commercial processes utilizing SB and SL as raw substrates. This article aims to explore SB and SL as cheaper sources of carbohydrates in the developing world for their industrial implications, their use in commercial products including commercial evaluation, and their potential to advance sustainable bio‐based fuel systems. Copyright © 2011 Society of Chemical Industry     

Management and Reuse of Mathematical Models in the Industrial Design Process

The use of model‐based methods to support planning, designing, and operating chemical processes and plants has recently gained an increased importance in the daily work of process engineers. The development of mathematical models through the use of standard flow sheet simulation tools requires the expertise of an experienced designer. Therefore, the value of existing models is not limited to the resources required for their development, but also includes value in the form of knowledge about an enterprise's products and production processes. The reuse of existing models and design experiences in order to lower the costs of model development is therefore economically desirable. This report gives an overview of the systematic long‐term management and use of mathematical models. Some motivating scenarios are used to derive the requirements for a model management system and to evaluate existing methods and tools. The results of these example scenarios are then used to guide the development of a model management system. After presenting a prototypical implementation the article concludes with an outlook on the future importance of model management systems.     

Role of lignin in a biorefinery: separation characterization and valorization

Lignin, a major component of the cell wall of vascular plants, has long been recognized for its negative impact and treated as a by‐product in a biorefinery. This highly abundant by‐product of the biorefinery is undervalued and underdeveloped due to its complex nature. The development of value‐added products from lignin would greatly improve the economics of the biorefinery. The inherent properties of lignin significantly affect the productivity of the biorefinery processes and its potential applications. Although the structure and biosynthetic pathway of lignin have been studied for more than a century, they have not yet been completely elucidated. In this mini‐review, the primary obstacles to elucidating the structure of native lignin, including separation and characterization, are highlighted. Several classical methods for separation and various NMR techniques, especially 2D HSQC NMR, for characterization of lignin are reviewed. Some potential applications of lignin are introduced. It is believed that a knowledge of the method to separate lignin from the cell wall and structural features of the lignin polymer from lignocellulosic materials will help to maximize the exploitation of lignocelluloses for the biorefinery as well as the utilization of lignin for novel materials and chemicals. © 2012 Society of Chemical Industry     

Catalytic organosolv fractionation of willow wood and wheat straw as pretreatment for enzymatic cellulose hydrolysis

BACKGROUND: Ethanol‐based organosolv fractionation of lignocellulosic biomass is an effective pretreatment technology for enzymatic cellulose hydrolysis to produce sugars and lignin within a biorefinery. This study focuses on the catalytic effect of H₂SO₄, HCl, and MgCl₂ on organosolv pretreatment of willow wood and wheat straw. RESULTS: The use of catalysts improved fractionation of both feedstocks. The maximum enzymatic cellulose digestibility obtained was 87% for willow wood (using 0.01 mol L^?1 H₂SO₄ as catalyst) and 99% for wheat straw (0.02 mol L^?1 HCl). Non‐catalytic organosolv fractionation at identical conditions resulted in 74% (willow wood) and 44% (wheat straw) glucose yield by enzymatic hydrolysis. Application of catalysts in organosolv pretreatment was particularly effective for wheat straw. The influence of the acid catalysts was found to be primarily due to their effect on the pH of the organosolv liquor. Acid catalysts particularly promoted xylan hydrolysis. MgCl₂ was less effective than the acid catalysts, but it seemed to more selectively improve delignification of willow wood. CONCLUSION: Application of catalysts in organosolv pretreatment of willow wood and wheat straw was found to substantially improve fractionation and enzymatic digestibility. The use of catalysts can contribute to achieving maximum utilization of lignocellulosic biomass in organosolv‐based biorefineries. Copyright © 2011 Society of Chemical Industry     

Towards design guidelines for virtual reality training for the chemical industry

Operator training in the chemical industry is important because of the potentially hazardous nature of procedures and the way operators' mistakes can have serious consequences on process operation and safety. Currently, operator training is facing some challenges, such as high costs, safety limitations and time constraints. Also, there have been some indications of a lack of engagement of employees during mandatory training. Immersive technologies can provide solutions to these challenges. Specifically, virtual reality (VR) has the potential to improve the way chemical operators experience training sessions, increasing motivation, virtually exposing operators to unsafe situations, and reducing classroom training time. In this paper, we present research being conducted to develop a virtual reality training solution as part of the EU Horizon 2020 CHARMING Project, a project focusing on the education of current and future chemical industry stakeholders. This paper includes the design principles for a virtual reality training environment including the features that enhance the effectiveness of virtual reality training such as game-based learning elements, learning analytics, and assessment methods. This work can assist those interested in exploring the potential of virtual reality training environments in the chemical industry from a multidisciplinary perspective.     

光滑球拟酵母发酵生产丙酮酸

丙酮酸是一种重要的有机酸 ,广泛应用于制药、日化、农用化学品和食品等工业中。相对于化工法生产的丙酮酸而言 ,发酵法生产的丙酮酸具有低成本、高质量等优势。考虑到球拟酵母属的多重维生素营养缺陷型菌株是目前发酵法生产中最常用和最具竞争力的生产菌株 ,因此重点介绍了发酵法生产丙酮酸在菌种、发酵条件优化等方面的研究进展 ,并给出了发酵法将来可能的发展方向。