Energy Integrated Distillation Column Sequence by Driving Force Method and Pinch Analysis

Energy savings is a major challenge in distillation operations. However, there is still one problem, which is how do we improve the energy efficiency of the existing distillation column systems without major modifications. Recently, a new energy efficient distillation columns methodology that will be able to improve energy efficiency of the existing separation systems without having major modifications has been developed. Therefore, the objective of this paper is to present a new improvement of the existing methodology by designing an optimal sequence of energy efficient distillation columns using a driving force method. Accordingly, the methodology is divided into four hierarchical sequential stages: i) existing sequence energy analysis, ii) optimal sequence determination, iii) optimal sequence energy analysis, and iv) energy comparison and economic analysis. The capability of this methodology is tested in designing an optimal synthesis of energy efficient distillation columns sequence of an aromatics separation unit. The existing aromatics separation unit consists of six compounds (Methylcyclopentane (MCP), Benzene, Methylcyclohexane (MCH), Toluene, m-Xylene and o-Xylene) with five direct sequence distillation columns being simulated using a simple and reliable short-cut method and rigorously tested within an Aspen HYSYS® simulation environment. The energy and economic analyses show that the optimal sequence determined by the driving force method has a better energy reduction with a total of 6.78% energy savings and a return of investment of 3.10 with a payback period of 4 months. It can be concluded that, the sequence determined by the driving force method is not only capable in reducing energy consumption, but also has a better economic cost for an aromatic separation unit

Heat integration techniques are now widely used for energy saving in petroleum processes. In this paper, an industrial hydrocracking process (UOP license) is retrofitted by pinch analysis as a significant tool for heat integration. The hydrocracking process is a main important conversion process in oil refineries and there has been sustained effort to improve its energy efficiency. Application of pinch analysis in retrofit of this process shows the heat exchanger network is operated efficiently. However, a large amount of energy is wasted from the hydrocracking unit, which their condition make no of use directly by the process during pinch analysis. Actually, most of the refining petroleum processes use considerably more energy than the operational minimum energy requirements because of their energy losses. These external energy losses are due to many factors, including normally inefficient or outdated equipment and process design, inadequate heat recovery, and poor integration of heat sources and sinks. However, without identifying the quality of the energy losses, it is difficult to determine how much of that energy is feasible to recover under realistic plant operating conditions. This is where exergy analysis can significantly assist in determining energy recovery opportunities. Thus, this paper is addressed to researchers who are assessing the quality of energy wasted in hydrocracking process, by using the principles of both pinch and exergy analysis. Based on the result obtained, the flue gas exhaust and the high pressure drop in reaction section can be considered as the exergy loss sources in this process. Moreover, the portion of waste energy that can be practically recovered is quantified.

Applying pinch and exergy analysis for energy efficient design of diesel hydrotreating unit

Pinch analysis approach to carbon-constrained energy sector planning

Optimal configuration of ternary distillation columns using heat integration with external heat exchangers

Carbon capture and storage (CCS) using solvent based absorption has the potential to significantly reduce the carbon intensity of power stations. It is one of a range of technologies that is necessary to be deployed in able to reduce greenhouse gas emissions at the lowest cost. However, the addition of CCS to power stations will increase the capital and operating expenditure of the power station and will reduce the net power produced from the power station. Therefore, minimising both the capital cost and the energy penalty associated with CCS will be imperative to ensuring that the cost of electricity of power stations with CCS remains competitive. This research uses multi-objective optimisation (MOO) of the CCS system applied to pulverised coal power stations using a combination of process simulation, heat integration using a linear programming form of pinch analysis and cost estimation. The benefit of combining MOO with automated pinch analysis is that the heat exchanger network does not need to be defined for the optimisation of the process synthesis. In this project, heat integration has shown to potentially lead to significant reductions in the energy penalty associated with the addition of CCS. Capturing 90 % of the CO2 in the flue gas, the energy penalty can be reduced from 38 % without heat integration, to just 14 % with a fully optimised and heat integrated solvent system. However, when the capital and operating costs are factored into the optimisation, to minimise the differential cost of electricity, the optimum level of heat integration may be more moderate, with energy penalties of between 25 and 30 %.

Currently, kraft pulp mills in Europe and North America are facing several challenges and have been forced to think along new products and new business areas. One opportunity is the conversion of chemical pulp mills into dissolving pulp mills by extracting hemicellulose prior to digesting via pre-hydrolysis. From the extracted wood chips, the more valuable dissolving pulp can be produced whereas the hydrolysate can be upgraded to high-value products. In this paper, pinch analysis is used to evaluate the consequences in the energy balance and utility system of a kraft mill converted into dissolving pulp production as well as to identify the potential for heat integration within the host mill itself, between the host mill and the pre-hydrolysis unit and with a hemicellulose upgrading process. The results show that proper heat integration within the host mill itself, and between the host mill and the pre-hydrolysis unit gives significant amounts of surplus steam which could be exported to a hemicelluloses upgrading process, used for power generation or to facilitate lignin extraction.

Distillation column is a well-known unit operation in chemical and petrochemical industries for an intended separation task. However, the energy usage still becomes a problem particularly for a multicomponent system of distillation columns sequence. Therefore, this research aims to investigate the applicability of Thermal Pinch Analysis to be employed in a distillation columns sequence to solve the problem. The method is complemented by the sequencing method of Driving Force which leads to a novel method namely Energy Integrated Distillation Columns Sequence (EIDCS). This systematic method has been designed for optimal distillation columns sequence and further energy saving by Thermal Pinch Analysis. The Driving Force Sequence was firstly determined by the use of Driving Force Plot. Then the shortcut and rigorous simulations have been carried out and the resulting data were extracted for Thermal Pinch Analysis at a fixed value of ΔTmin at 10 °C. Next, the Problem Table Algorithm (PTA) was constructed to indicate the possible energy saving for the distillation columns sequence. Finally, the proposed Heat Exchanger Network (HEN) via Grid Diagram that satisfies the energy requirement was constructed. A case study of 6-component Aromatic Mixture has been selected to evaluate the proposed EIDCS method in this study.

Process-design intensification situated under the umbrella of Novel Process Windows heads for integrated and simplified smart-scaled (micro/meso) flow process design in a holistic picture. The example taken here is direct adipic acid synthesis which is an important intermediate for the nylon industry. To investigate its potential for process simplification cost and energy analysis is searched. Process simulation of the flow process with 40 %, 50 % and 98 % conversion is made. An energy efficient process is searched for this novel direct route in particular considering its heat integration for the three conversion cases. For this purpose pinch analysis is employed and a new heat exchanger network (HEN) is designed with minimum total annualized cost. The improvement of the HEN results in 50 - 70 % saving in operating cost which enables to pay back the extra capital cost requirement in less than one year in all cases. The benefit of heat integration is seen to be reduced with increased conversion due to the reduced heat load in the process. Another consideration here is the selection of the heat exchanger type. The pinch analysis is restricted to shell and tube heat exchangers, however by utilization of compact (including microchannelbased) heat exchangers additional benefits in terms of cost and plant complexity can be achieved.

The article is devoted to consideration of issues related to assessing the energy efficiency of a coal mining enterprise. Coal mining enterprises are characterized by a large volume of energy intensive ore mining operations. The article presents possible ways of energy saving in the mining industry. During the research, a system of energy efficiency indicators for coal mining enterprises is presented. Materials and methods. The article proposes a system of indicators for coal enterprises based on existing methods and approaches to assessing energy efficiency. Energy consumption dependence graphs, benchmarking, and pinch analysis are considered as a starting point. Results. The study presents a system of energy efficiency indicators for coal mining enterprises. The proposed system has several levels. The existing methods and approaches for assessing this important indicator for industrial enterprises in the coal industry as a whole are considered. The author’s approach to formalizing the system of energy efficiency indicators for coal mining enterprises is proposed. The significance of energy audit as a key assessment measure is indicated and its stages are highlighted. The influencing factors determining energy costs and their reduction for a coal mining enterprise are systematized, barriers preventing the practical implementation of energy saving measures are analyzed. Discussion. The proposed metrics system provides a comprehensive framework for assessing the energy efficiency of coal mining enterprises at various levels. Its flexibility allows it to be applied to the analysis of individual equipment units, production processes, and overall enterprise performance. Its multi-level approach provides a detailed understanding of energy consumption, which allows for informed decision-making to optimize operations. At the equipment level, the metrics system evaluates the energy consumption and efficiency of individual machines and devices. At the production process level, the metrics system analyzes the energy consumption and efficiency of various stages of coal mining. At the enterprise level, the metrics system provides a comprehensive assessment of overall energy efficiency. It takes into account energy consumption at all levels and allows enterprises to compare their performance with each other and with industry benchmarks. Conclusion. Energy efficiency assessment of a coal mining enterprise allows to understand how and where energy is used, where its use can be improved, and how to reduce its costs. To conduct an energy efficiency assessment, the article proposes a system of indicators, highlighting the features of an energy audit. The main advantage of the proposed system of indicators is that it covers a wide range of energy consumption indicators, which are carefully selected and located at different levels of detail. In general, a balanced approach to the level of detail and generalization in the system of indicators provides flexibility in adapting indicators to specific research questions and helps to interpret the results in the context of structural differences between energy systems. Resume. Overall, the proposed metrics system offers a comprehensive approach to analyzing the energy efficiency of coal mining enterprises, covering all levels of operations. Its use allows enterprises to improve energy efficiency, reduce operating costs, and contribute to a more sustainable coal mining industry. Suggestions for practical applications and directions for future research. The use and implementation of the developed system at a coal mining company allows it to improve energy efficiency, reduce operating costs and contribute to a more sustainable coal mining industry.

A multiperiod approach for waste heat and renewable energy integration of industrial sites

Heat integration of biochemical ethanol production from straw – A case study

An improved design method for retrofitting industrial heat exchanger networks based on Pinch Analysis

Pinch analysis provides a systematic approach to targeting the minimum heating and cooling requirements of industrial processes and to designing heat exchanger networks that approach this target. Decades after its introduction, the method remains essential for energy efficiency, decarbonisation, and retrofit studies across sectors such as chemicals, pulp and paper, food, and refining. In addition, numerous papers have proposed extensions to PA but these are often left isolate and unavailable for future development and implementation. In short, tool development has not kept pace with academic progress and today’s industry requirements. Many practitioners rely on bespoke or basic spreadsheets or legacy desktop applications that make it difficult to scale analyses, embed the results in modern workflows, or experiment with emerging pinch techniques. OpenPinch fills this gap with an open-source Python toolkit that implements advanced pinch analysis and total site integration methods. The library offers typed schemas for robust data ingestion, modular analysis routines that span unit operation to process, site and regional scales, and export paths that maintain compatibility with conventional spreadsheet workflows. As illustrated by a survey of current pinch tools, a distinctive contribution is its comprehensive implementation of (unified) total site heat integration combined with multiple utilities, both isothermal and non-isothermal ones, via a combination of problem-table transformations, temperature-interval segmentation, and iterative assignment. The basis of these algorithms were reported in Tarighaleslami et al. (2017a). This technical note documents the architecture, algorithms, and data flow of OpenPinch, highlighting an end-to-end example of a pulp mill case study as well as key directions for future extension.

Optimization of ethylene process design