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The ethanol fermentation process using molasses as the feedstock has been studied. The process alternatives, compared to the original fermentation process described in the literature, have been modeled using single and double distillation columns. Short-cut and rigorous models for the distillation column were compared and their influence on the process economics indicate the rigorous model to be more exact, the short-cut model to be faster and more convenient for comparative analysis of finding the optimal process structure. The process with the single distillation column was shown to be the optimal variant requiring the lowest equipment and utilities cost. Estimated net present worth value for the single column was 29.6 MUSD and for the double columns 27.1 MUSD. A heat pump use was found to be a possible option for heat integration. The span of temperatures in distillation columns was confirmed to be the decisive factor for the economy of heat pump use. The pay back time was more than 5 years. Thermal integration reduced the total annual costs by 27% as compared to the basic process scheme.

Simultaneous parameter and structural optimization of an existing complex and energy intensive continuous process have been studied using rigorous models. The method that was recently developed to sequentially optimize retrofits has been extended to a stepwise simultaneous superstructural approach, using available process simulators and optimization software capabilities. An extended procedure has been employed for retrofits using a three-step approach: (i) generation of a process superstructure by pinch analysis; (ii) formulation of a mixed integer nonlinear programming (MINLP) model and its simplification into a relaxed nonlinear programming (NLP) model; (iii) simultaneous optimization, first by a process simulator and than by the NLP algorithm. Pinch analysis offers alternative retrofit designs for postulating the superstructure. An advantage of the relaxed NLP formulation over the MINLP one is that it can be easily generated. Poor local optima due to nonlinear interconnections between alternative solutions have been avoided by applying a direct search complex algorithm using the simulator. The approach has been illustrated by maximizing the annual profit of an existing methanol plant. The optimal solution yields additional savings of 5.17 MUSD per annum (6.75% of the total income) which is 6.5 times the savings obtained by the earlier sequential optimization method. © 2000 Elsevier Science Ltd. All rights reserved.

Short cut synthesis method was developed in order to find the best structure of heat integrated distillation system. It was applied to studying a process for recovery of six light products from multicomponent mixture. The method was demonstrated as a very effective one and led to the best heat integrated sequences. A computational simulation of the process and pinch analysis were used for thermodynamic optimization of energy consumption. The influence of depreciation cost on the total annual cost of the process was studied in distillation columns sequencing.

The design of small specialty chemical plants is dealt with in the first part of this paper. The influence of different parameters on decision making between batch and continuous operation was taken into account. The results in the first part of the paper confirm the conclusions from the previous two papers that in the case of single-purpose equipment, the continuous plant is more profitable than the batch one for all capacities, but the batch process with multi-purpose equipment can be favoured over the continuous one when the equipment arrangement is appropriate (minimum number of process units and small size factor). In the second part of the paper, important economic factors (variable, fixed and equipment capital costs, product price) which have an influence on the net present worth of batch and continuous plants are discussed in detail. Variable costs have the greatest effect on the net present worth. Increased variable costs reduce the profitability of the batch or the continuous project. Merging of tasks makes the batch alternative more attractive at small production rates because economy of scale has a stronger effect on small size equipment. Merging can offset other disadvantages of batch processes, therefore it is cheaper to have one larger unit than many small units. The limiting capacity was determined where the batch process becomes more profitable than the continuous one. It depends on the process type and its annual costs. The manufacture of dibutylphtalate from butanol and phthalic anhydride is discussed as an additional case study.

This paper describes the simultaneous optimization of process flowsheets and their heat exchanger networks (HENs) using rigorous models and detailed cost functions. An optimization procedure is proposed by which tradeoffs between oprating plus capital costs of a process and utility plus capital costs of their heat integrated HENs are simultaneously taken into account. The procedure relies on a direct search optimization method to reduce the effects of nonconvexities and to enable real large-scale industrial problems with a large number of streams to be solved. A special match-dependent cost targeting formula for HEN is introduced to adjust HEN capital costs to different construction characteristics. A Discrete Complex Algorithm (DCA) is proposed for direct search optimization in a reduced feasible region defined over sets of discretized decision variables. The direct search results in a final HEN design. A simple, yet very robust, nonlinear programming (NLP) optimization model is developed to design HEN with practically any number of streams using the same capital cost function for HEN as in the direct search. The whole optimization procedure is illustrated by the optimization of an existing large-scale chemical process at increasing levels of simultaneity ranging from the sequential to the simultaneous HEN optimization.

The role of pressure is not taken into account when using composite curves on a temperature/enthalpy flow rate ( T I ) diagram to predict minimum utility requirement in a chemical process. Usually, pressure effects are neglected by assuming small pressure drops through the process. However, sometimes, the energy analysis should be applied to a part of the process involving large pressure changes, e.g. an expander coupled directly to a compressor. In such a case, enthalpy changes indicate neither the quality nor the energy flow direction between the streams exchanging energy. The problem of high pressure exchangers in pinch technology is now solved by a combination of exergy analysis in a temperature vs power availability ( T P x ) diagram in addition to the usual approach in the pinch technology.

Influence of utility prices on the optimum process structure was studied. Different prices of utilities and increasing investment costs (inflation) over three different decades have been considered. In one decade the fuel price was very low while in another one it was very high. Process structures in these decades were derived using pinch and nonlinear programming methods on a hydrodealkylation of toluene process with diphenyl recycled. The results showed that structures differed in the three decades because of different prices and for that reason a common process configuration, usable both for eventual future high or low fuel prices, could be developed.

In the present paper an algorithmic procedure for generating innovative reactor network designs for complex reaction schemes is presented. Computational methodology is derived from the basic principles of reaction and mixing. Candidate reactor networks are generated by expanding the solution space into regions where different levels of mixing are required. Directions of extending the design space are identified by using formal optimization theory. A set of candi-date reactor networks is generated in a finite number of the solution space extensions. The derived methodology eliminates the requirement for an postulated superstructure and the use of qualitative knowledge for finding the optimal solution. With certain modifications the proposed design procedure can also be used to support the design of batch processes. The generated reactor structures are truly optimal. The proposed methodology is illustrated by an example of integrating chemical reactors into the overall process.

A pinch design method for sequencing distillation columns in enthalpy flow rate / temperature ( I / T ) diagram has been compared with heuristic rules. Area between integrated columns has been investigated in connection with heat flows of columns and temperature differences in and between the columns. Heuristic methods for systematic synthesis of initial sequences of multicomponet separations can be explained with I / T diagram. Among heat integration combinations of columns structures with bigger intercolumn areas are better designs. The findings in connection with the heat integration were tested on an acetaldehyde process.

In this chapter, an extended strategy for efficient and applicable water minimization in process industries is presented. The strategy effectively incorporates environmental, organizational and economic aspects accompanying the water mini­mization issue. The strategy was tested and applied in several water minimi­zation projects involving chemical and process industries. Four case studies are presented for illustration purpose. The results obtained indicate that in most cases water efficiency can be greatly improved by using technologically, environmentally and economically viable solutions.

The present paper is concerned with computer aided design of a specialty chemical product plant. Decisions about batch/continuous operation, time fraction of operation, plant capacity, amount and energy balances including energy integration are the first decisions to be met. Special criteria that could help to decide when a batch process may be favoured over a continuous one, are described. 12 months per year production is rescheduled to 3 months per year production. Design procedure with technological and economic results of different operating variants is described. Analysis of the results shows that the continuous process after energy integration is preferrable over a batch one for all capacities, unless special requirements exist for process related reasons.

Human evolution is governed by non-equilibrium thermodynamics of bio-systems. Its laws are determining the ever increasing anthropogenic extraction of non-renewable materials and energy carriers, and pollution endangering the mankind to self-destroy the human race just the same way as the produced poisonous ethanol kills yeast on fermentation of juice of grapes. The dominating power of natural laws regarding materials, energy, information, and innovations is shown in the paper; it is stronger than the cultural awareness of mankind demonstrated by law, education, ethics, religion, and morality. Evidently, only natural catastrophes can make people act in a different way, towards lowering the pollution. Although catastrophes are increasing at an exponential rate, it may be too late for human action when heat waves, sea level rise, desertification, wood fires, and floods act strong enough to make the mankind respond culturally (non-naturally). Therefore, it is crucial to understand the natural laws of evolution and their influence on the human society. It is also vital for students, having the farthest reaching time horizon of their life cycle, to be acquainted with the consequences foreseen, and the adaptation strategy is available for the future decades.

Publisher Summary A successful food and beverage processing operation needs a stable supply of high-quality water and the appropriate wastewater treatment. The finished product is often not simply a result of the raw material, but is also affected by changes in the feedwater quality. In addition to water quality, the second most important requirement is the reasonable cost of the feedwater. High-quality feedwater is required in food processing and this can be achieved by proper treatment that should ideally involve the least treatment possible. Catchments of water sources are seriously affecting feedwater treatment and supply. Population and urbanization can give rise to a scarcity of fresh water resources, especially those of high quality. Water should be safe for human consumption and aesthetically acceptable: free from organic matter, color, taste, and odor, all of which are unacceptable in water to be used for food and beverage processing operations. The quantity of freshwater used in the food industry is very high. Where fresh water is lacking, it is very important to use technologies that enable the direct or indirect reuse of potable water; this chapter describes currently available feedwater treatment methods. Among these methods, membranes are the most promising and it is clear that membranes with very high water permeability need to be developed. Overall system performance would be optimized with the introduction of more efficient hybrid water treatment systems, but the problems of the design and operation of such installations remain as yet unresolved.

Unsustainable consumption mostly refers to energy resources and materials' utilization, fostered by human activity. Therefore, energy consumption represents a major challenge when approaching sustainable development issues. Despite many environmental strategies relying on im- provements in energy and material efficiency, the World's energy demand is likely to increase in line with its population. In addition, cultural patterns of human activities are closely related to energy consumption patterns. This paper discusses the relationship between energy consumption and human overpopulation, which is one of the critical issues when approaching sus- tainability. Furthermore, this paper argues about cultural influences and barriers for the rational use of energy. The paper juxtaposes shallow to deep ecology and stresses the importance of transition to deep ecology, which draws on a wide diversity of ultimate philosophical or religious premises, by seeing Nature and culture as fundamentally intertwined. Education has a crucial role in revising energy consumption patterns. This paper also stresses the importance of education for sustainable development as a required ap- proach to a sustainable society. It argues about those conflicts between dif- ferent human goals that should be taken into account in educational systems. Universities should act as agents in promoting transformative change towards sustainability. Thus, the importance of incorporating sustainability principles

Fuel cells, process heat integration and open gas turbine electricity cogeneration can be optimized simultaneously using nonlinear programming (NLP) algorithm. The NLP model contains equations of structural and parametric optimization. The nonlinear programming model is used to optimize complex and energy intensive continuous processes. The procedure does not guarantee a global cost optimum, but it does lead to good, perhaps near-optimum designs. The optimization approach is illustrated by a complex process of low-pressure Lurgi methanol production, giving an additional profit of 2,6 MUSD/a. The plant, which is producing methanol, has a surplus of hydrogen (H2) flow rate in purge gas. H2 shall be separated from the purge gas by an existing pressure swing adsorption (PSA) column. Pure H2 can be used as fuel in fuel cells.

The paper presents the combined conceptual-rigorous approach to the problem of energy integrated process synthesis of large-scale chemical processes. The process design is composed of three main steps, i.e. simulation step, conceptual design step (extended Pinch design method, determination of promising modifications, their assessment, selection of the most promising modification) and rigorous design step (structural and parameter optimization). The proposed method was tested using a case study of a simplified ammonia production where the marginal cost decrease of 1,2 % has been achieved compared to the base process design.

Framing the Issue of Sustainability.- Science and Sustainability: who knows best?.- Sustainability: Ecological, Social, Economic, Technological, and Systems Perspectives.- US EPA/Academia Collaboration for a Green Engineering Textbook For Chemical Engineering.- Innovative Industrial Ecology Education Can Guide Us to Sustainable Paths.- The sustainable industrial development: reality and vision.- Sustainable Pathways.- Clean technologies for wastewater management in seafood canning industries.- Kinetic Analysis of Aerobic Composting of Tobacco Industry Solid Waste.- Preventative Measures in Production from the Point of Sustainability.- Environmetric strategies to classify, interpret and model risk assessment and quality of environmental systems.- Carbon storage: the economic efficiency of storing CO2 in leaky reservoirs.- An Integrated Computer Aided System for Generation and Evaluation of Sustainable Process Alternatives.- Pollution prevention and environmental management systems - tools to obtain a sustainable development.- Sustainability Metrics.- Technology sensitive indicators of sustainability.- Metrics for supply chain sustainability.- Quantifying technological aspects of process sustainability: a thermodynamic approach.- Defining and Measuring Macroeconomic Sustainability - The Sustainable Economy Indices.- Environment as a factor of national competitiveness in manufacturing.- Indicators for sustainable energy development from a negentropic perspective.- Sustainability indicators for anticipating the fickleness of human-environmental interaction.- Measuring Sustainability - Index of Balanced Sustainable Development.- Evaluating the Environmental Friendliness, Economics and Energy Efficiency of Chemical Processes: Heat Integration.- Eco-efficiency reporting exemplified by case studies.- Interpolation for creating hydrogeological models.- Indicators of Sustainable Production.- Remote Sensing as a Tool for Achieving and Monitoring Progress Toward Sustainability.- Summary of Panel Discussions.

The need for aggregated sustainability information has become a concrete goal of nations committed to contributing to sustainable development and to the establishment of an integrated economic, environmental and social information system for the sustainability assessments.

The simulatenous heat and power integration between processes using mixed integer nonlinear programming (MINLP) contains equations of structural and parametric optimization of the nonretrofitted or retrofitted plants. High pressure steam production and generation of electricity using a steam turbine are included in the integrated structure. MINLP can predict: the optimum energy target of the integration between processes, steam and electricity production. The approach has been illustrated by four complex processes (solvent production, formalin production, methanol production and oil refinery) using MINLP. The objective function have maximized the annual profit of heat and power integration to 303,2 kUSD/a.

Publisher Summary This chapter discusses the optimization of ethylene process design. The influence of components separation was treated with two different simulators using two different sequences of distillation columns. Considerable differences in reboiler and condenser heat flow rates resulted in economic analysis of particular sequences. The same sequence gave the lowest total annual costs in spite of the use of two different simulators compared to the second best option proposed for distillation columns sequence. Use of different models resulted in different heat-integrated structures and, therefore, different profits. Heat integration resulted in total annual cost reduction between 9% and 19%. The goal of the process design is to select the structure and parameters to give the minimum sum of the depreciation and operating cost. The general methodology that leads to the best scheme is called “process synthesis.” The thermodynamic method is used as a first step in the synthesis of ethylene production process case study.

Waste minimisation in process industries consists of source reduction and recycling. It is possible to save money by reducing waste treatment and disposal costs, to improve the quality of products, to reduce potential environmental liabilities, to protect public and worker’s health, to increase safety and to protect the environment. Waste minimization by source reduction and recycling is the cheapest method for waste reduction. It can be adopted by all process industries: textile, pulp and paper, leather, food, chemical, oil, ceramic, pharmaceutical, metallurgical.

This special issue of the journal offers 18 selected papers presented at a NATO Advanced Research Workshop (ARW) entitled Technological Choices for Sustainability, held in Maribor, Slovenia from 13 to 17 October 2002. Speakers and presenters from 27 countries from Europe and North America were assembled to discuss the scientific and technological issues confronting the implementation of the idea of sustainable development. The Scientific and Environmental Affairs Division of NATO was the main sponsor of the workshop; the co-sponsors were several ministries of the Republic of Slovenia, The British and the American Embassies in Slovenia, and Adria Airways. The main motivation for the workshop was to seek a scientific understanding of the idea of sustainability and evaluate potential technological choices for the journey towards sustainability. We observed that thus far sociopolitical debates have overwhelmed the scientific discourse on sustainability. This gap between extant rhetoric and needed knowledge was also pointed out in a report of the U.S. National Research Council in Our common journey: a transition toward sustainability (National Academy Press, Washington, D.C., 1999): The political impetus that carried the idea of sustainable development so far and so quickly in public forums has also increasingly distanced it from its scientific and technological base. As a result, even when the political will necessary for sustainable development has been present, the knowledge and know-how to make some headway often has not.

Thermodynamic analysis of reactors and their heat integration into overall process is presented. Heat balance of a reactor can be divided into four items: (1) reaction enthalpy is produced or consumed; (2) heat of reaction is transferred to or from the reacting fluid; (3) heat is exchanged between the reacting streams; and (4) heat is exchanged with the environment. This division enables us to separate the reactor from the heat-exchanger network. Composite and grand composite curves of the heat-exchanger networks can be constructed and the reactor T/I profile can be matched with the grand composite curve by changing the reactor conditions (feed temperature and composition, degree of conversion, pressure, contacting etc.). This paper describes general principles of the analysis and results for adiabatic, exothermic plug-flow reactors.

Thermodynamic analysis of reactors and their heat integration into the overall process is presented. The practical energy balance of a reactor can be divided into four items: reaction enthalpy is produced or consumed, reaction enthalpy is transferred to or from the reacting fluid, heat is interchanged between the reacting fluids, and heat is exchanged with the environment. This division enables the separation of the reactors from the heat exchangers network. The last three items can be integrated into the process profile and the first one is drawn separately as a reactor profile (chemical utility) on the temperature/enthalpy diagram. The appropriate placement of exothermic reactors is above the pinch, while the appropriate placement of endothermic reactors is below the pinch. The reactor profile can be matched with the process profile by changing the process structure (number and volume of reactors, heat exchangers network, the pressure of boilers) and reactor parameters (feed temperature and composition, degree of conversion, pressure, heat interchange and exchange, contacting etc.).

A consideration of second-law analysis has been extended from the heat exchanger network to an overall energy balance of a chemical process. This enables the simultaneous integration of all kinds of energy-active apparatus (e.g. reactors, compressors, turbines, boilers, refrigerators, coolers, heaters) and hot feeds or effluents into a process flowsheet. The apparatus and the feeds or effluents together represent a utility exchanger network (UEN), process streams are utilized by several types of energy (utilities) that are of a chemical, mechanical, electrical, transmissible, radiative, or heat flow origin. Inherent and avoidable utilities are distinguished. An action of each utility on the enthalpy change of the process stream is represented in a temperature—enthalpy diagram by the corresponding utility stream. Hot utility streams are composed into a hot composite curve (UCC). It sums up the energy inflows and energy production of the system, called energy donors. On the other hand, cold utility streams are composed into a cold UCC that comprises energy outflows and energy consumption (energy acceptors). Process streams are excluded in this step. By matching both UCCs the method enables the direct targeting of an economical overall utility system through is structural and parametric modifications. Targeting is facilitated by using general rules for appropriate integration of energy donors and energy acceptors relative to the utility pinch temperature. At the same time, the improved energy system changes the dynamical performances; the control configuration must be adopted to the new structure of the total system. The method is based on a detailed thermodynamic analysis of process units and is followed by an optimal thermodynamic synthesis of the total system. The final detailed parametrical optimization is similar to the classic pinch analysis. It deals with process streams and brings additional savings. The whole procedure has been tested on an existing chemical process and its effectiveness has been proved.

During the recent war, the karst area of Croatia, Bosnia & Herzegovina and Kosovo and Metohija has been jeopardized by hazardous waste and deserves particular attention because of its exceptional ecological sensitivity and unfortunately unscrupulous destruction of natural resources, infrastructure, homes and enterprises. Data on contaminant levels from water and soil samples collected before 1995. didn’ t show significant contamination of the investigated locations in Croatia (Oštarije, Ogulin, Transformer Station "Konjsko", Rivers Cetina and Jadro) by organochlorinated pesticides and PCBs. Also there were no ecologically significant PCBs contamination of soil near Transformer Stations in Delnice and Kaštela, while in the area of ETS "Komolac", TS "Zadar" and TS "Bilice" significant levels of PCB were observed. Levels of PCBs in soil samples from Bosnia & Herzegovina sampled during autumn 2003 and during June and July 2004 (altogether 47 samples) show significant (more than 10 ppm) of total PCBs levels in Bihać, Tuzla and Tešanj. If we compare the levels of PCB in the soil near TS "Zadar" and TS "Bilice" in Croatia and three locations in Bosnia & Herzegovina (Bihać, Tuzla and Tešanj) by the criteria of tolerance accepted in the Netherlands, the levels of contamination at these locations far exceeds tolerable levels that do not require remediation. During June 2004, 4 soil samples were collected from 4 sites in Kosovo and Metohija, but levels of PCBs were relatively low (under 1 ppm). Taking into account location of destroyed Zadar, Bilice and Dubrovnik Electrical Transformer Stations, there was some speculation regarding the potential hazard from organohalogenated toxicants to the Lake Vransko and the coastal sea around the Zadar, Šibenik and Dubrovnik areas. Sediment and some aquatic organism samples were collected and analyzed from mentioned areas. Results indicate there were no significant or high levels of contaminants in the areas of Lake Vransko, Šibenik, Dubrovnik (Petke location), while in these areas: Mikulandra bay near Šibenik, Rijeka Dubrovačka, Brodanova location, Marina near Vruljica creek in Zadar, significantly higher level of PCBs were observed. During autumn of 2003 and June 2004 (altogether 60 samples) in Bosnia & Herzegovina sediment samples were collected for PCBs analysis from 9 rivers (Bosna, Una, Miljacka, Spreča, Buna, Bijela, Gostilja, Jala and Tešanjka), and from seven water sources and creeks. In some sediment samples from Bosnian rivers significant levels of PCB were observed, even more than 1000 ppb. In Kosovo and Metohija 8 sediment samples were collected during June 2004, from rivers Ibar, and Sitnica, but only in some samples significant levels of PCBs were observed.

The authors in an extermely concise manner elaborate the use of logistics in the funktioning of transportation chains. Special stress is given to rational transportation on the part of its "organizer". The role of management in the multimodal transport is inreplaseable, since without it and its right decisions logistical process cannot function successfully in the complex and unintempted transportation chins.

Hydrolysis of reactive triazine dyes and by-products was monitoring in order minimize the wastewater pollution. Thin-layer chromatography with densitometry was performed for their monitoring and quantification and shown as a suitable method for monitoring the multiple stage reactions of reactive dye production which therefore achieved the save on chemicals and reduction of wastewater pollution.