Development of performance functions for economic performance assessment of process control systems

Economic performance assessment (EPA) of control systems is receiving increasing attention in both academia and industry. It addresses the estimation of the potential benefits resulting from control upgrade projects and monitoring and improvement of economic performance of the control system. Economic performance of control systems can often be related to crucial controlled variables dynamically and when controlled variables move away from an optimal operating point either more profit will be made or more cost will be incurred. This relation can be modelled by performance functions (PFs). When the multivariate nature of a process’s economic model is not considered, PFs of different controlled variables are referred to as individual performance functions. Otherwise, PFs of dependent controlled variables are referred to as joint performance functions. PFs play an important role in the latest techniques of EPA. There appears, however, to be no systematic method for developing PFs. The lack of such a method restrains further research into EPA, as without well-established PFs an EPA cannot be conducted smoothly and therefore cannot effectively support decision-making for management. The development of PFs is a bottleneck in the further research into EPA. Furthermore, the multivariate nature of processes has not been taken into account sufficiently as far as the relevant literature is concerned, which hampers the accuracy of PFs and accordingly the accuracy of economic assessment results. The contributions of this thesis lie in the following aspects: • A methodology for developing PFs is proposed, based on the PF development for an electric arc furnace, a grinding mill circuit and a stage of a bleach plant. • A comprehensive case study of an EPA of three controllers of a grinding mill circuit is conducted using a newly published framework to show the significance of PFs and how to perform an EPA systematically. • The current practice and guidelines on the control and functional/economic performance assessment of grinding mill circuits are captured using a survey study. The multivariate nature of an electric arc furnace’s economic model is investigated and joint performance functions are built based on individual performance functions. A multivariate economic assessment is conducted that shows how joint performance functions can help to provide a more accurate estimate of the economic performance of a controlled process. A web-based survey study on grinding mill circuits in mineral processing industries is conducted. One of its objectives is to obtain general PFs of grinding circuits. The survey results provide instructive insight into the PFs of grinding circuits. Furthermore, an in-depth literature review is conducted and the relationship between the product’s particle size distribution of grinding mill circuits and mineral recovery in downstream flotation circuits is revealed. The PFs of a grinding mill circuit being considered are formed, based on the survey results and literature study. An investigation into the PF development of a stage of a bleach plant is performed and crucial ideas used for their development are abstracted. A methodology for developing PFs for the EPA of control systems is then proposed by synthesising the methods used in the PF development described above. This methodology mainly includes the following stages: Stage 1: Determine information required for PF development. • Process operation and control understanding. • Process economics understanding. Stage 2: Gain required information on PF development. • PF-related information elicitation using survey research. • PF-related information available in the literature, including textbooks, journal papers, conference papers. • PF-related information from plant tests. Stage 3: Obtain suitable performance measures. Stage 4: Make suitable assumptions. Stage 5: Determine PFs. Stage 6: Develop Joint PFs. An economic assessment of three controllers (a nonlinear model predictive controller, a decentralized controller and three single-loop proportional-integral-derivative controllers) of the considered grinding mill circuit is conducted, using an EPA framework published recently to show the central role of PFs in the EPA and how to perform an EPA systematically. The circuit’s PFs, developed as described above, are used for the assessment. The EPA also shows that the improvement in the economic performance with the nonlinear model predictive controller mainly results from the improvement of the operating point and the controlled variables’ variation reduction only contributes a small part to the overall improvement, due to the characteristic of the PF of the circuit’s product particle size distribution. In addition, a web-based survey study is conducted and the current practice and guidelines on the control and functional/economic performance assessment of grinding mill circuits are captured. The questionnaire used for the study includes five segments. The first part identifies the respondents and the second part is intended to obtain background information on the milling circuits. The third part concerns the choice of key process variables and their economic impact. Part four involves the control of milling circuits and control loop performance and part five covers economic issues.Thesis (PhD)--University of Pretoria, 2010.Electrical, Electronic and Computer Engineeringunrestricte

XVIII International Coal Preparation Congress

Changes in economic and market conditions of mineral raw materials in recent years have greatly increased demands on the ef fi ciency of mining production. This is certainly true of the coal industry. World coal consumption is growing faster than other types of fuel and in the past year it exceeded 7.6 billion tons. Coal extraction and processing technology are continuously evolving, becoming more economical and environmentally friendly. “ Clean coal ” technology is becoming increasingly popular. Coal chemistry, production of new materials and pharmacology are now added to the traditional use areas — power industry and metallurgy. The leading role in the development of new areas of coal use belongs to preparation technology and advanced coal processing. Hi-tech modern technology and the increasing interna- tional demand for its effectiveness and ef fi ciency put completely new goals for the University. Our main task is to develop a new generation of workforce capacity and research in line with global trends in the development of science and technology to address critical industry issues. Today Russia, like the rest of the world faces rapid and profound changes affecting all spheres of life. The de fi ning feature of modern era has been a rapid development of high technology, intellectual capital being its main asset and resource. The dynamics of scienti fi c and technological development requires acti- vation of University research activities. The University must be a generator of ideas to meet the needs of the economy and national development. Due to the high intellectual potential, University expert mission becomes more and more called for and is capable of providing professional assessment and building science-based predictions in various fi elds. Coal industry, as well as the whole fuel and energy sector of the global economy is growing fast. Global multinational energy companies are less likely to be under state in fl uence and will soon become the main mechanism for the rapid spread of technologies based on new knowledge. Mineral resources will have an even greater impact on the stability of the economies of many countries. Current progress in the technology of coal-based gas synthesis is not just a change in the traditional energy markets, but the emergence of new products of direct consumption, obtained from coal, such as synthetic fuels, chemicals and agrochemical products. All this requires a revision of the value of coal in the modern world economy

Waste Material Recycling in the Circular Economy

This book highlights current challenges and developments in waste material recycling in the framework of a circular economy. The increase in the standard of living has resulted in the large consumption of several materials, mainly polymers. Therefore the problem of waste recycling, specifically polymer recycling, in an environmentally friendly way is more urgent than ever. Nowadays, more specialized recycling methods are required to manage a wide variety of wastes. Over fourteen chapters in three sections, this book addresses such topics as chemical recycling techniques, recycling of polyethylene, denim production and recycling, valorization of waste materials, urban mining, the circular economy, and much more

Current Air Quality Issues

Air pollution is thus far one of the key environmental issues in urban areas. Comprehensive air quality plans are required to manage air pollution for a particular area. Consequently, air should be continuously sampled, monitored, and modeled to examine different action plans. Reviews and research papers describe air pollution in five main contexts: Monitoring, Modeling, Risk Assessment, Health, and Indoor Air Pollution. The book is recommended to experts interested in health and air pollution issues

Best Available Techniques (BAT) Reference Document for Large Combustion Plants. Industrial Emissions Directive 2010/75/EU (Integrated Pollution Prevention and Control)

The BAT Reference Document (BREF) for Large Combustion Plants is part of a series of documents presenting the results of an exchange of information between the EU Member States, the industries concerned, non-governmental organisations promoting environmental protection, and the Commission, to draw up, review, and -where necessary- update BAT reference documents as required by Article 13(1) of Directive 2010/75/EU on Industrial Emissions. This document is published by the European Commission pursuant to Article 13(6) of the Directive. This BREF for Large Combustion Plants concerns the following activities specified in Annex I to Directive 2010/75/EU: - 1.1: Combustion of fuels in installations with a total rated thermal input of 50 MW or more, only when this activity takes place in combustion plants with a total rated thermal input of 50 MW or more. - 1.4: Gasification of coal or other fuels in installations with a total rated thermal input of 20 MW or more, only when this activity is directly associated to a combustion plant. - 5.2: Disposal or recovery of waste in waste co-incineration plants for non-hazardous waste with a capacity exceeding 3 tonnes per hour or for hazardous waste with a capacity exceeding 10 tonnes per day, only when this activity takes place in combustion plants covered under 1.1 above. In particular, this document covers upstream and downstream activities directly associated with the aforementioned activities including the emission prevention and control techniques applied. The fuels considered in this document are any solid, liquid and/or gaseous combustible material including: - solid fuels (e.g. coal, lignite, peat); - biomass (as defined in Article 3(31) of Directive 2010/75/EU); - liquid fuels (e.g. heavy fuel oil and gas oil); - gaseous fuels (e.g. natural gas, hydrogen-containing gas and syngas); - industry-specific fuels (e.g. by-products from the chemical and iron and steel industries); - waste except mixed municipal waste as defined in Article 3(39) and except other waste listed in Article 42(2)(a)(ii) and (iii) of Directive 2010/75/EU. Important issues for the implementation of Directive 2010/75/EU in the Large Combustion Plants sector are the emissions to air of nitrogen oxides, sulphur dioxide, hydrogen chloride and fluoride, organic compounds, dust, and metals including mercury; emissions to water resulting especially from the use of wet abatement techniques for the removal of sulphur dioxide from the flue gases; resource efficiency and especially energy efficiency. This BREF contains 12 Chapters. Chapters 1 and 2 provide general information on the Large Combustion Plants industrial sector and on the industrial processes used within this sector. Chapter 3 provides data and general information concerning the environmental performance of installations within the sector in terms of water consumption, the generation of waste and general techniques used within this sector. It also describes in more detail the general techniques to prevent or, where this is not practicable, to reduce the environmental impact of installations in this sector that were considered in determining the BAT. Chapters 4 to 9 provide the following information given below on specific combustion processes (gasification, combustion of solid fuel, combustion of liquid fuel, combustion of gaseous fuel, multi-fuel combustion and waste co-incineration). Chapter 10 presents the BAT conclusions as defined in Article 3(12) of the Directive. Chapter 11 presents information on 'emerging techniques' as defined in Article 3(14) of the Directive. Concluding remarks and recommendations for future work are presented in Chapter 12.JRC.B.5-Circular Economy and Industrial Leadershi

Pertanika Journal of Science & Technology

TesisEl propósito de este trabajo de investigación fue determinar el grado de relación entre el clima organizacional y la satisfacción laboral en los trabajadores de la Asociación para el Desarrollo Empresarial en Apurímac, Andahuaylas. A fin de proporcionar al directivo de la institución, sugerencias de cambio, reforzamiento y/o de mejora. Para la realización de este estudio se determinó como muestra al total de la población, conformada por 30 trabajadores a quienes se les aplicó un cuestionario estructurado, tipo escala de Likert, para diagnosticar el clima organizacional, compuesto por 21 ítems correspondiente a 5 dimensiones, y para medir la satisfacción laboral, compuesto por 14 ítems correspondiente a 2 dimensiones, validados por tres expertos en la materia. El análisis de fiabilidad de los cuestionarios arroja un coeficiente de Alf a de Cronbach para la escala de clima organizacional y satisfacción laboral de 0.796 y 0.721 respectivamente confiables. La hipótesis principal señalaba que existía relación entre el clima organizacional y satisfacción laboral. La principal conclusión comprobó que hay relación entre las dos variable, es decir, existe relación significativa positiva entre el clima organizacional y satisfacción laboral. A nivel de las hipótesis específicas se comprobó las dimensiones de clima organizacional la estructura, autonomía, relaciones interpersonales, identidad se correlacionaron de forma significante y positiva con la satisfacción laboral. Sin embargo no se encontró relación entre la dimensión recompensa con la satisfacción laboral en la Asociación para el Desarrollo Empresarial el Apurímac