Systematic and Optimization-Based Synthesis and Design of Chemical Processes

Computer tool supported process design methodology

Conceptual chemical process design in a sustainable technological world

Performing a pollution prevention assessment of a chemical process design is typically resource intensive. Time constraints, a lack of resources and limited inhouse expertise, particularly in developing nations, have resulted in inconsistent and non-routine identification of pollution prevention opportunities. To address these problems, computer based tools may be developed to enable designers to rapidly understand environmental implications and provide suggestions of process modifications. A software prototype, P2TCP (Pollution Prevention Tool for Continuous Processes) is presented. P2TCP provides support and helps facilitate pollution prevention assessments of continuous chemical processes at all stages of design.There is a significant need for quantitative methods for comparison of process alternatives. Although chemical and safety hazard rating schemes have a long history, there is no universally accepted method for comparison in terms of potential environmental impacts. Full health and environmental risk analysis is not suitable for conceptual process design decision making but models or indicators can provide a suitable approach. A number of methods are incorporated in P2TCP.The benefits of heat and mass integration tools for pollution prevention (P2) have been widely demonstrated. However no tool has been developed specifically to assist in the intuitive process of systematically identifying alternatives for continuous chemical processes which may reduce waste generation and energy consumption. P2TCP incorporates an expert system for P2 design analysis which is complementary to existing integration and simulation tools. The key features of the analysis system are presented.KeywordsChemical process design analysisenvironmental comparisonpollution prevention

A Computer-Aided Platform for Simultaneous Process Synthesis and Intensification

The design and scheduling of chemical batch processes: Computational complexity studies

The constant tightening of environmental regulations and the ongoing need to reduce operating costs have posed a challenge for the design of any chemical process. Process engineers use process simulators to help them perform calculations that will, ultimately, result in design parameters or operating conditions for a plant or process. Exergy is a potential indicator that can aid in the design of energy efficient chemical processes and plants. The exergy concept has been increasingly used as a tool to locate the critical energy use in many industrial processes, both chemical and non‐chemical. However, currently most process simulators in the market do not offer the capability of calculating the exergy of a process. An open‐source exergy calculator has been created by embedding the calculation procedure in an open‐source chemical process simulator. This improves process simulation by including a potential tool for design teams to quickly evaluate several process options in detail in order to understand their energy utilisation. A simple exergy analysis for a gas processing facility is used to demonstrate the capabilities of the tool. The analysis shows where the largest quantities of exergy are being consumed within the plant, thus pointing to areas where improvement in energy usage can be made. The use of exergy as a potential design and retrofit tool is also discussed. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.

A process design framework for considering the stability of steady state operating points and Hopf singularity points in chemical processes

The paper presents a stochastic methodology for handling uncertainty in process development as part of a general framework for batch and continuous process models. The method combines systematic modelling procedures with Hammersley sampling based uncertainty analysis and a range of sample-based sensitivity analysis techniques which are used to quantify predicted performance uncertainty and identify key uncertainty contributions. The methodology was implemented on a batch chemical reactor process and some clear recommendations as to how to reduce the uncertainty in the main output variables are obtained.

Optimization problem of complex system under uncertainty

The objective of this research project is the development of a second generation in-duct sorbent injection technology as a cost-effective compliance option for the 1990 Clean Air Act Amendments. Research focused on the Advanced Coolside Process, which has shown the potential of exceeding the performance targets of 90% SO{sub 2} removal and 60% sorbent utilization. In Task 5, Conceptual Process Design and Economic Evaluation, the economics of the CONSOL Advanced Coolside Process as a Clean Air Act compliance option were evaluated. A conceptual process design for full-scale, coal-fired applications is described. Advanced Coolside is compared to conventional Limestone Forced Oxidation (LSFO) wet FGD technology. The process economics for coal sulfur levels ranging from 1.0% to 3.5% (as-received) and plant sizes ranging from 160 to 512 gross MW were investigated, In addition, the economics of on-site versus off-site lime hydration and the cost sensitivity to delivered pebble lime and hydrate prices are investigated, Advanced in-duct sorbent injection enjoys a capital and levelized cost advantage relative to LSFO in all cases examined in this study. As a result of this study and others made during this contract, the following conclusions can be made: (1) The capital cost of Advanced Coolside is 55% to 60% less than that of LSFO and varies slightly depending on coal sulfur content and plant size. (2) The total levelized SO{sub 2} control cost advantage relative to LSFO varies from 15% to 35% over the range of coal sulfur contents and plant sizes evaluated. This cost advantage is sensitive to sorbent transportation charges. As a result, the economics are site-specific. (3) The experimental optimizations based on interim economic analyses were the key to capital and levelized cost reductions.

Multi-criteria screening of carbon dioxide utilization products combined with process optimization and evaluation

Uncertainty or error occurs as a result of a lack or misuse of knowledge about specific topics or situations. In this review, we recall the differences between error and uncertainty briefly, first, and then their probable sources. Then, their identifications and management in chemical process design, optimization, control, and fault detection and diagnosis are illustrated. Furthermore, because of the large amount of information that can be obtained in modern plants, accurate analysis and evaluation of those pieces of information have undeniable effects on the uncertainty in the system. Moreover, the origins of uncertainty and error in simulation and modeling are also presented. We show that in a multidisciplinary modeling approach, every single step can be a potential source of uncertainty, which can merge into each other and generate unreliable results. In addition, some uncertainty analysis and evaluation methods are briefly presented. Finally, guidelines for future research are proposed based on existing research gaps, which we believe will pave the way to innovative process designs based on more reliable, efficient, and feasible optimum planning.

One of the priority issues in green chemistry is to devise of greener and sustainable chemical strategies and processes to reduce or eliminated the use of hazardous substances. The development of bio-based materials has been constantly increasing, and there is a global effort in agreement with the demands of sustainable management for reducing reliance of fossil resources. In this sense there are green polymerization systems improved to reach increased yields and produce polymers with high molar mass and with specific microstructure characteristics. In the same way, biocatalysis in green chemistry reactions are performer under mild conditions of temperature, pressure and pH. However, along with new materials, chemical processes and reactors must be redesign and developed to guarantee the requirements and meet the demand for green chemical products. Substantial differences with traditional chemical process are based on the synthesis of materials changing the solvents selections and the implementation of continuous reactors, as well as in evaluating the effectiveness of the process through factors such as atom economy, environmental factor, and process mass intensity to implement an industrial green process. This chapter is a review of the processes that have been design and developed to achieve to maximize efficiency and reduce waste.

Flexible heat exchanger network design for chemical processes with operation mode changes

Empirical sizing guidelines such as tail volume coefficients have long been used in the early aircraft design phases for sizing stabilizers, resulting in conservatively stable aircraft. While successful, this results in increased empty weight, reduced performance, and greater procurement and operational cost relative to an aircraft with optimally sized surfaces. Including flight dynamics in the conceptual design process allows the design to move away from empirical methods while implementing modern control techniques. A challenge of flight dynamics and control is the numerous design variables, which are changing fluidly throughout the conceptual design process, required to evaluate the system response to some disturbance. This research focuses on addressing that challenge not by implementing higher order tools, such as computational fluid dynamics, but instead by linking the lower order tools typically used within the conceptual design process so each discipline feeds into the other. In thisresearch, flight dynamics and control was incorporated into the conceptual design process along with the traditional disciplines of vehicle sizing, weight estimation, aerodynamics, and performance. For the controller, a linear quadratic regulator structure with constant gains has been specified to reduce the user input. Coupling all the disciplines in the conceptual design phase allows the aircraft designer to explore larger design spaces where stabilizers are sized according to dynamic response constraints rather than historical static margin and volume coefficient guidelines.