Process design optimization strategy to develop energy and cost correlations of CO2 capture processes

In the context of CO2 emissions reduction from power plants, CO2 removal from flue gas by chemical absorption with monoethanolamine is analyzed in detail. By applying process integration and multi-objective optimization techniques the influence of the operating conditions on the thermo-economic performance and on the optimal thermal integration within a power plant is studied. With the aim of performing optimization of complex integrated energy systems, simpler parameterized models of the CO2 capture process are developed. These models predict the optimized thermo-economic performances with regard to the capture rate, flue gas flowrate and CO2 concentration. When applied to overall process optimization, the optimization time is considerably reduced without penalizing the overall power plant model quality. This approach is promising for the preliminary design and evaluation of process options including a CO2 capture unit

Systematic Methods for the Design of Industrial Clusters with Capped Carbon Emissions

Hydrocarbon resource centric economies, such as Qatar, are highly vulnerable to the impact of climate policy. Climate policies could decrease demand of hydrocarbon, lowering prices and would force countries to adopt mitigation technologies. Thus, having a climate strategy is important to meet future constraints. This work develops approaches to enable policy makers to systematically explore alternative emissions reduction paths in an integrated framework. The methods introduced explore the element of time, resources management, Carbon Capture Utilization and Sequestration (CCUS) and energy integration including Renewable Energy (RE) use. The industrial city or cluster is taken as a system and modelled through balances and constraints, which were optimized applying deterministic solvers. Two approaches were developed. The first is a multi-period carbon planning approach that enables the assessment of different carbon dioxide reduction options, which may be applied to guiding transitions to a future target emission. Second is a systematic approach that enables the identification of economically optimal natural gas allocation in different conversion technologies under carbon emission targets with energy synergy. The multi-period planning approach identified allocation of carbon dioxide between sources and potential sinks in each period, compared cost elements simultaneously and resulted in a low cost network across all periods. Furthermore, the role of RE was investigated through a robust MILP. The results highlighted significant differences in economic impact of alternative footprint reduction policies. The systematic natural gas monetization approach simultaneously determined natural gas monetization and carbon dioxide management through CCUS as well as RE strategies. The method considered heat and power integration, enabling the assessment of the Natural gas (CH₄), CO₂ and Energy nexus. Several case studies were solved that indicated benefits of having optimized policies that screen all mitigation options given economic and environmental objectives out preformed adopted prescribed policies found around the globe

Economic and environmental strategies for process design

This paper first addresses the definition of various objectives involved in eco-efficient processes, taking simultaneously into account ecological and economic considerations. The environmental aspect at the preliminary design phase of chemical processes is quantified by using a set of metrics or indicators following the guidelines of sustainability concepts proposed by . The resulting multiobjective problem is solved by a genetic algorithm following an improved variant of the so-called NSGA II algorithm. A key point for evaluating environmental burdens is the use of the package ARIANE™, a decision support tool dedicated to the management of plants utilities (steam, electricity, hot water, etc.) and pollutants (CO2, SO2, NO, etc.), implemented here both to compute the primary energy requirements of the process and to quantify its pollutant emissions. The well-known benchmark process for hydrodealkylation (HDA) of toluene to produce benzene, revisited here in a multiobjective optimization way, is used to illustrate the approach for finding eco-friendly and cost-effective designs. Preliminary biobjective studies are carried out for eliminating redundant environmental objectives. The trade-off between economic and environmental objectives is illustrated through Pareto curves. In order to aid decision making among the various alternatives that can be generated after this step, a synthetic evaluation method, based on the so-called Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) (), has been first used. Another simple procedure named FUCA has also been implemented and shown its efficiency vs. TOPSIS. Two scenarios are studied; in the former, the goal is to find the best trade-off between economic and ecological aspects while the latter case aims at defining the best compromise between economic and more strict environmental impact

Developing tools for determination of parameters involved in CO₂ based EOR methods

To mitigate the effects of climate change, CO₂ reduction strategies are suggested to lower anthropogenic emissions of greenhouse gasses owing to the use of fossil fuels. Consequently, the application of CO₂ based enhanced oil recovery methods (EORs) through petroleum reservoirs turn into the hot topic among the oil and gas researchers. This thesis includes two sections. In the first section, we developed deterministic tools for determination of three parameters which are important in CO₂ injection performance including minimum miscible pressure (MMP), equilibrium ratio (Kᵢ), and a swelling factor of oil in the presence of CO₂. For this purposes, we employed two inverse based methods including gene expression programming (GEP), and least square support vector machine (LSSVM). In the second part, we developed an easy-to-use, cheap, and robust data-driven based proxy model to determine the performance of CO₂ based EOR methods. In this section, we have to determine the input parameters and perform sensitivity analysis on them. Next step is designing the simulation runs and determining the performance of CO₂ injection in terms of technical viewpoint (recovery factor, RF). Finally, using the outputs gained from reservoir simulators and applying LSSVM method, we are going to develop the data-driven based proxy model. The proxy model can be considered as an alternative model to determine the efficiency of CO₂ based EOR methods in oil reservoir when the required experimental data are not available or accessible

Modeling and Control of Post-Combustion CO2 Capture Process Integrated with a 550MWe Supercritical Coal-fired Power Plant

This work focuses on the development of both steady-state and dynamic models for an monoethanolamine (MEA)-based CO2 capture process for a commercial-scale supercritical pulverized coal (PC) power plant, using Aspen PlusRTM and Aspen Plus DynamicsRTM. The dynamic model also facilitates the design of controllers for both traditional proportional-integral-derivative (PID) and advanced controllers, such as linear model predictive control (LMPC), nonlinear model predictive control (NMPC) and H? robust control.;A steady-state MEA-based CO2 capture process is developed in Aspen PlusRTM. The key process units, CO2 absorber and stripper columns, are simulated using the rate-based method. The steady-state simulation results are validated using experimental data from a CO2 capture pilot plant. The process parameters are optimized with the goal of minimizing the energy penalty. Subsequently, the optimized rate-based, steady-state model with appropriate modifications, such as the inclusion of the size and metal mass of the equipment, is exported into Aspen Plus DynamicsRTM to study transient characteristics and to design the control system. Since Aspen Plus DynamicsRTM does not support the rate-based model, modifications to the Murphree efficiencies in the columns and a rigorous pressure drop calculation method are implemented in the dynamic model to ensure consistency between the design and off-design results from the steady-state and dynamic models. The results from the steady-state model indicate that between three and six parallel trains of CO2 capture processes are required to capture 90% CO2 from a 550MWe supercritical PC plant depending on the maximum column diameter used and the approach to flooding at the design condition. However, in this work, only two parallel trains of CO2 capture process are modeled and integrated with a 550MWe post-combustion, supercritical PC plant in the dynamic simulation due to the high calculation expense of simulating more than two trains.;In the control studies, the performance of PID-based, LMPC-based, and NMPC-based approaches are evaluated for maintaining the overall CO2 capture rate and the CO2 stripper reboiler temperature at the desired level in the face of typical input and output disturbances in flue gas flow rate and composition as well as change in the power plant load and variable CO2 capture rate. Scenarios considered include cases using different efficiencies to mimic different conditions between parallel trains in real industrial processes. MPC-based approaches are found to provide superior performance compared to a PID-based one. Especially for parallel trains of CO2 capture processes, the advantage of MPC is observed as the overall extent of CO2 capture for the process is maintained by adjusting the extent of capture for each train based on the absorber efficiencies. The NMPC-based approach is preferred since the optimization problem that must be solved for model predictive control of CO2 capture process is highly nonlinear due to tight performance specifications, environmental and safety constraints, and inherent nonlinearity in the chemical process. In addition, model uncertainties are unavoidable in real industrial processes and can affect the plant performance. Therefore, a robust controller is designed for the CO2 capture process based on ?-synthesis with a DK-iteration algorithm. Effects of uncertainties due to measurement noise and model mismatches are evaluated for both the NMPC and robust controller. The simulation results show that the tradeoff between the fast tracking performance of the NMPC and the superior robust performance of the robust controller must be considered while designing the control system for the CO2 capture units. Different flooding control strategies for the situation when the flue gas flow rate increases are also covered in this work

Generation of Simulation Based Operational Database for an Acid Gas Removal Plant with Automatic Calculations

Computer aided process design is improving with newer and newer tools. One of such tools is the automatic calculation technique that enables the combination of different software tools to enhance the efficiency of the calculations. In our research work Aspen HYSYS model of a petrochemical plant is built in order to simulate responses of an existing plant to the changes in the composition and amount of feed material. The Aspen HYSYS is connected to Microsoft Excel program; simu-lated operational data are stored in an operational database and transported to Excel for further analysis. The automatic calculation completed with the two software tools mutually strengthens their merits and results in enhanced insight into the operational features of any plant. Comparison of the projected input parameters of the petrochemical plant studied shows that the extension of the plant is badly needed. Cash-flow analysis suggests that the extension is profitable

On the decarbonization of chemical and energy industries: Power-to-X design strategies

Tesis por compendio de publicaciones[ES]Hoy en día, la preocupación por la sostenibilidad está dando lugar a todo un nuevo sistema económico. Este nuevo paradigma afecta a todos los sectores como la agricultura, la industria, el sector financiero, etc. Dos de los más afectados son la industria química y el sistema energético debido a su configuración actual y, estos dos sectores son particularmente estudiados en esta tesis. En cuanto a la industria química, la producción electroquímica es uno de los métodos más atractivos para producir productos químicos de forma sostenible dejando atrás la producción tradicional no renovable. En esta tesis se ha prestado especial atención a la producción sostenible de amoníaco. Se han evaluado dos rutas diferentes, la primera utiliza la electrólisis del agua y evalúa diferentes tecnologías de separación del aire en función de la escala, y la segunda utiliza la biomasa como materia prima. Utilizando estos productos electroquímicos, es posible construir una nueva industria química sostenible. En esta tesis se propone la síntesis de carbo- nato de dimetilo (DMC) utilizando metanol renovable, amoníaco y dióxido de carbono capturado. En cuanto al sector energético, la introducción de fuentes renovables es esencial para alcanzar los objetivos propuestos. En este punto, el almacenamiento de energía será crucial para garantizar la satisfacción de la demanda debido a las fluctuaciones inherentes a las energías solar y eólica. Esta tesis se centra en la evaluación de productos químicos como forma potencial de almacenamiento o como vectores de energía. Se estudia la transformación del amoníaco en electricidad a escala de proceso proporcionando los resultados necesarios para implementar esta alternativa a escala de red. El diseño y el funcionamiento de las insta- laciones basadas en renovables se abordan simultáneamente, incluyendo la ubicación de las unidades debido a que los recursos renovables estan distri- buidos. Se propone un sistema integrado para utilizar productos químicos como vectores energéticos para diferentes aplicaciones energéticas en una región de España, calculando las capacidades, la operación y la ubicación óptima de las instalaciones. Además, se realiza la integración de diferentes energías renovables intermitentes y no intermitentes junto con diferentes tecnologías de almacenamiento desde una perspectiva económica y social para satisfacer una determinada demanda eléctrica. Todos estos sistemas y herramientas propuestos contribuyen a crear un escenario futuro en el que los sectores químico y energético se transforman para ser menos impactantes en el medio ambiente que nos rode