Novel visualization and algebraic techniques for sustainable development through property integration

The process industries are characterized by the significant consumption of fresh resources. This is a critical issue, which calls for an effective strategy towards more sustainable operations. One approach that favors sustainability and resource conservation is material recycle and/or reuse. In this regard, an integrated framework is an essential element in sustainable development. An effective reuse strategy must consider the process as a whole and develop plant-wide strategies. While the role of mass and energy integration has been acknowledged as a holistic basis for sustainable design, it is worth noting that there are many design problems that are driven by properties or functionalities of the streams and not by their chemical constituency. In this dissertation, the notion of componentless design, which was introduced by Shelley and El-Halwagi in 2000, was employed to identify optimal strategies for resource conservation, material substitution, and overall process integration. First, the focus was given on the problem of identifying rigorous targets for material reuse in property-based applications by introducing a new property-based pinch analysis and visualization technique. Next, a non-iterative, property-based algebraic technique, which aims at determining rigorous targets of the process performance in materialrecycle networks, was developed. Further, a new property-based procedure for determining optimal process modifications on a property cluster diagram to optimize the allocation of process resources and minimize waste discharge was also discussed. In addition, material substitution strategies were considered for optimizing both the process and the fresh properties. In this direction, a new process design and molecular synthesis methodology was evolved by using the componentless property-cluster domain and Group Contribution Methods (GCM) as key tools in developing a generic framework and systematic approach to the problem of simultaneous process and molecular design

Comparison of safety indexes for chemical processes under uncertainty

PresentationThe fatal consequences of industrial incidents have made evident the need for suitable tools to develop inherently safer process designs. Traditionally, in a process design project, the evaluation of safety aspects is left for analysis after the detailed design has been completed. This approach leads to the use of control loops, barriers and protection layers as the only ways to prevent incidents and to reduce the possible outcomes. An alternative to this approach is the application of the concept of inherent safety, which was introduced to set up several principles that aim to enhance process safety by eliminating, avoiding or minimizing sources of risk. In this work, we present a comparison of different safety metrics in their role to evaluate the risk associated with a given process design. The indices selected for consideration are better applied at the conceptual stage of the process design, and they were the Dow’s fire and explosion index (F&EI), the fire and explosion damage index (FEDI), the process route index (PRI) and the process stream index (PSI). All these indices use different input information and their outcomes have different rankings. The metrics were applied to an ethylene production process to identify risk levels, and the location of streams and pieces of equipment that pose the highest risk within the process. An evaluation of the indices in their capability to track design changes in operating conditions aiming to improve the safety level of the process was developed. To perform the assessment of the safety metrics in a more extensive manner, an uncertainty analysis based on a Monte Carlo simulation framework was implemented and compared to the traditional use of single-value design variables. Within this context, an insightful assessment of uncertainty’s effect on process safety characteristics was achieved because of the identification of ranges of safety- relevant performance outcomes (zones of risks and opportunities) that can be probabilistically characterized. The approach was applied to a case study related to the production of ethylene from shale gas. The results showed how some indexes are better suited to capture the risk characteristics associated with the process when changes in the operating conditions of the section with highest risk were implemented. The methodology can be extended to other processes of interest, and may serve as a basis for the safety and process design community to propose adjustments in the structure of the safety indices based on a better understanding of their performance and reliability as part of the efforts towards the continued improvement of those safety metrics

A Hybrid Method for Evaluating Biomass Suppliers – Use of Intuitionistic Fuzzy Sets and Multi-Periodic Optimization

Part 5: Fuzzy LogicInternational audienceEvaluation of biomass suppliers is a time-dependent problem that requires assessment of different supply schemes in different periods. This paper presents a hybrid method for evaluating biomass suppliers that combines Intuitionistic Fuzzy Sets (IFS), linear programming (LP) and multi-periodic optimization (MPO). IFS allow evaluators to express their hesitation when they assess alternative suppliers. LP is used to estimate weights of evaluation criteria and calculate suppliers’ ratings in a specific period. These ratings are utilized by a MPO model to determine what type and how much feedstock should be supplied by each supplier in each period

Managing Uncertain Industrial Flares during Abnormal Process Operations using an Integrated Optimization and Monte Carlo Simulation Approach

In this work, an integrated optimization framework with Monte Carlo (MC) simulation techniques is suggested for the systematic synthesis of energy alternative tools, such as cogeneration (COGEN) systems, which can effectively manage industrial flares with uncertain occurrence patterns. The optimization model that was previously developed is now extended to incorporate the risk associated with the uncertain nature of the flaring events that are probabilistically characterized based on empirically meaningful historical samples. The model aims at minimizing the total annualized cost including fixed and operating costs of the system, the value of by- and co-products (i.e., power, excess heat), and regulatory taxes/credits associated with Green House Gases (GHGs). A base case ethylene production plant is presented to illustrate the applicability of the proposed approach and highlight trade-offs between different performance objectives (economic, environmental and energy-related). The results show that some of the examined factors (i.e., CO2 tax savings) can be severely affected by small variations in flaring profiles, whereas others are only slightly affected by such variability (i.e., power vs. heat generation curves, fixed and operating costs). Therefore, the uncertain nature of flaring events may be of high importance in process performance and should be inevitably considered during abnormal situation management. 1 2017 Elsevier B.V.Scopu

Inherently safer design tool (i-SDT): A property-based risk quantification metric for inherently safer design during the early stage of process synthesis

In this work, an Inherently Safer Design Tool (i-SDT) is presented for early stage process synthesis to characterize and track the risk associated with different life-cycle phases of industrial processes. It also helps to develop characteristic equations for different safety parameters (i.e., flammability, explosiveness, toxicity, etc.) under various operating conditions. This property-based inherent safety quantification metric is a tailor made semi-quantitative safety analysis tool which provides safety assessment in a continuous manner to overcome the subjective nature of the existing available safety metrics. The core of this design and safety assessment tool is probabilistic risk quantification using accident and incident investigation (with over 600 incidents and within 27 years of time span), a property integration model and an exponential curve fitting method. The proposed safety metric has the flexibility to operate by identifying the major accident-prone units/sections of a process, as well as the major safety and operating parameters. The final output of this i-SDT tool is a cluster safety parameter score (CSP) which provides insights regarding the investigated unit/section or process for carrying out inherent safer design using a very limited amount of process information. The developed i-SDT tool was applied to compare different technologies of Ammonia processes in order to assess the safer option in terms of risks associated with the accident-prone unit/section and to highlight the areas of safety improvement in any existing process using the inherent safer design principles. In the future, this metric can can be embedded into a techno-economic framework to perform the cost and safety analysis simultaneously using available materials, design and accident information. - 2018 Elsevier LtdThis paper was made possible by NPRP grant No 6-678-2-280 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the author[s]. The author thanks Ahmed AlNouss for his contribution in developing the necessary simulation models for the presented Ammonia case study.Scopu

Surplus diagram and cascade analysis technique for targeting property-based material reuse network

Recycle of process and waste streams are among the most effective resource conservation and waste reduction strategies. In many cases, recycle/reuse is dictated by sink constraints on properties of the recycled streams. In this work, we introduce an algebraic technique to establish rigorous targets on the minimum usage of fresh resources, maximum direct reuse, and minimum waste discharge for property-based material reuse network. Two new tools have been developed. A new graphical tool called the property surplus diagram is firstly introduced to provide a basic framework for determining rigorous targets for minimum fresh usage, maximum recycle, and minimum waste discharge. The tools also determine the property-based material recycle pinch location. The Property Cascade Analysis (PCA) technique is next established to set targets via a tabular approach. PCA eliminates the iterative steps typically associated with a graphical approach. Along with the minimum fresh and waste targets, the material allocation target is another key feature of the PCA. A network design technique is also presented in this paper to synthesise a maximum resource recovery (MRR) network that achieves the various established targets. The procedures developed in this paper constitute a generalisation to the composition-based graphical and algebraic techniques developed for water and hydrogen recovery networks. Two case studies are solved to illustrate the applicability of the developed procedures

Selection of energy conservation projects through Financial Pinch Analysis

© 2017 Elsevier Ltd Energy conservation measures are an important means of reducing operating costs and greenhouse emissions. However, one of the barriers to the implementation of such projects is the limited availability of financial resources. Pinch Analysis, which was initially developed to conserve thermal energy and improve energy efficiency in industrial processes, is extended in this paper to address the problem of energy conservation project selection. A new method is developed to include financial cash flows for appropriate selection among independent projects. This study applies Financial Pinch Analysis to select multiple independent projects from a large pool of candidate projects, subject to different funding constraints. To account for the time value of money, Net Present Value is used to determine the financial feasibility of the projects against various funding options. The applicability of the proposed method considers a pool of projects with equal and unequal lives, as well as the financial risk associated with individual projects. In this study, risk is estimated by calculating the certainty equivalent cash flows of the projects. A graphical approach to obtain optimal insightful solutions is presented and demonstrated through three illustrative examples of energy conservation projects in the pulp and paper and cement industries

A pinch analysis approach to project selection problem

Project selection is a very important decision that every firm has to take; in fact, this decision plays a major role in the prosperity of the firm. Pinch analysis, which was initially developed to conserve energy and improve energy efficiency in industrial process, is now being extended to non-conventional areas. In this paper, pinch analysis is applied to select multiple independent projects from a large pool of viable projects, subject to budget constraints. The underlying mathematical optimization problem is discussed and a graphical approach to obtain optimal insightful solutions is presented. Applicability of the proposed methodology is demonstrated through an illustrative example of energy conservation in the Indian cement industry. © 2017 IEEE