Total Annual CO2 Emissions Research Articles

Extractive Distillation of Isobutyl Alcohol and Isobutyl Acetate Using Dimethyl Sulfoxide: Process Design and Intensification

AbstractWe have designed a separation process of isobutyl alcohol (52.0 mol%) and isobutyl acetate (48.0 mol%) mixture using conventional extractive distillation (ED) and extractive dividing‐wall column (E‐DWC) with the solvent dimethyl sulfoxide (DMSO). The binary mixture exhibits a minimum boiling azeotrope that is sensitive to pressure. Thermodynamic analyses have shown that the vacuum pressures work better compared to the atmospheric pressure when DMSO is the solvent. Based on the separation with a purity of 99.9 mol%, the E‐DWC process has resulted in 9.6 % and 4.8 % reductions in the total annual cost and CO2 emission rates, respectively, in comparison to the conventional method. After further intensification using the heat pump technique, the E‐DWC process with the solvent DMSO has provided more than 40.0 % reduction in energy consumption compared to the ED systems studied in the literature using the solvents butyl propionate and dimethylformamide.

The design and control of heat-integrated EDWC processes for the separation of THF/IPA/water

Extractive dividing wall columns (EDWC) and heat integration are effective process intensification strategies for separating azeotropes. In this study, the steady-state and dynamic control for the separation of tetrahydrofuran/isopropanol/water using a combination of EDWC and heat integration with intermediate reboilers are systematically investigated. The feasibility of the extractive distillation process is evaluated by analyzing the thermodynamic characteristics of the mixture through phase diagrams, and the three-column extractive distillation (TCED) process is established as the basic process. To enhance the energy and economic efficiencies, as well as environmental sustainability, three improved processes are proposed. Compared with TCED, the optimal process (E-EDWC-HI2) reduces the total annual costs, energy consumption, and CO2 emissions by 22.35 %, 41.77 %, and 26.28 %, respectively. In addition, a dynamic control structure is proposed for the E-EDWC-HI2, which exhibits robustness against disturbances in the feed flow rate and composition. This study provides guidance for the design and dynamic control of complex distillation processes.

Heat Pump-Assisted extractive Pressure-Swing distillation with integrated feed Preconcentration/Solvent recovery for Isopropanol-Benzene-Water separation

Recently, heat-integrated pressure-swing distillation (HIPSD) has been explored for recovering isopropanol and benzene from wastewater, but the process remains highly energy-intensive. Given the dilute nature of the feed, intensified extractive distillation with an integrated preconcentration column (IEDP) is more suitable. However, previous research has often overlooked the critical role of pressure and lacked rigorous optimization of operating pressure in such systems. In this article, we developed novel extractive pressure-swing distillation with integrated feed preconcentration/solvent recovery column (IEPSD) by introducing a pressure-swing configuration and incorporate energy-saving technologies to achieve more sustainable and cost-effective separation processes. First, thermodynamic analysis is conducted to explore the effect of pressure on extractive pressure-swing distillation. Then, a parallel genetic algorithm is applied for rigorous optimization, followed by the application of heat integration and heat pump. The IEPSD is superior to IED in terms of total annual cost (TAC) and CO2 emission. With the inclusion of energy-saving technologies, IEDPHI and IEPSDHI further reduced TAC by 5.29% and 7.40%, and cut CO2 emissions by 25.18% and 24.03%, respectively, compared to their base processes. The use of a heat pump is particularly advantageous for IEPSD due to its lower boiling temperatures under vacuum pressure, leading to the development of IEPSDHIHP, which offered an additional 22.36% CO2 reduction and marginally lower TAC than IEPSDHI. Ultimately, IEPSDHIHP proves to be the best option, offering a 51.15% TAC reduction and 68.42% CO2 emissions reduction compared to HIPSD. In summary, the developed IED and IEPSD processes, especially with heat integration and heat pump technologies, offer significant economic and environmental advantages over conventional HIPSD.

Sustainable and efficient separation of ternary multi-azeotropic mixture butanone/ethanol/water based on the intensified reactive extractive distillation: process design, multi-objective optimization, and multi-criteria decision-making

It is of great significance and necessity to develop a sustainable and efficient separation scheme of butanone (MEK), ethanol (EtOH), and water, which are usually formed during the cinepazide maleate synthesis process. To the best of our knowledge, the systematic separation of this ternary multi-azeotropic mixture remains comparatively less studied, compounded by the significant challenges posed by its intricate composition comprising four azeotropes and three distillation boundaries. Therefore, a systematic approach by integrating the process design, multi-objective optimization, and multi-criteria decision-making (MCDM) methods was proposed to achieve the sustainable separation. Initially, three separation schemes, i.e., triple-column extractive distillation (TCED), double-column reactive extractive distillation (DCRED), and side stream intensified double-column reactive extractive distillation (SS-DCRED), were mainly explored via the thermodynamic and kinetic analysis. Subsequently, the multi-objective particle swarm optimization (MOPSO) algorithm was employed to optimize the process based on three objectives namely the total annual cost (TAC), CO2 emissions, and process route index (PRI). Finally, an efficient MCDM method combining CRITIC and TOPSIS was employed to rank the Pareto front solutions of the corresponding process design. Based on the comparison results, the optimal TCED process exhibits the lowest PRI with a decrease of 50.61% and 55.06% compared to that of the SS-DCRED and the DCRED, respectively. It also shows the best performance simultaneously considering economic, environmental, and safety criteria. Of note, the SS-DCRED separation process exhibited the lowest TAC, with a decrease of 60.67% and 11.45% compared to that of the TCED and the DCRED, respectively.

Investigation of sustainable operation oriented- economic, process and environment based multi-criteria optimization of large scale methanol production plant

Methanol is one of the main raw materials and a building block for many essential chemicals in the industry, and it is widely produced from the synthesis gas. It is used as a fuel, solvent, inhibitor, antifreeze agent, and in producing a variety of chemicals including olefins and paraffin. The global demand for methanol is 70 million tons per year and it is estimated to grow by a factor of 6–8% per year so it is necessary to develop a methanol production process, which is economical, and environment friendly. The multi-objective optimization (MOO) approach is used to optimize the large scale Lurgi two-step methanol synthesis process using the non-dominated sorting genetic algorithm-II (NSGA-II) to find the Pareto front solutions involving the process, economic, and environmental-based objectives. Methanol production rate, total energy consumption, total annual CO2 emissions, and profit are considered as objectives. The five decision variables include syngas molar flow, reactor feed pressure, reactor 1 temperature, reactor 2 temperature, and by-product mass flow in the methanol distillation column. Two constraints are set on ethanol mole fraction in the methanol stream, and methanol mole flow in water to the treatment stream. Three optimization cases (two bi-objective and one tri-objective) are developed. In the Case 1 study, CO2 emissions decreased by 65.83%, the methanol production rate increased by 10.11%, and total energy was reduced by 57.55%. The Pareto ranking is carried out using the Preference Ranking On the Basis of Ideal-average Distance (PROBID) method and the best optimal solution is reported for all cases.

Safety-driven design of carbon capture utilization and storage (CCUS) supply chains: A multi-objective optimization approach

Carbon capture, utilization, and storage supply chains (CCUS) play a pivotal role in achieving sustainability targets but necessitate meticulous risk identification and mitigation measures. Traditional safety assessments often occur post-design, constraining proactive risk management efforts. Hence, there is a pressing need to optimize safety performance during the design stages. To address this challenge, a framework for evaluating and optimizing CCUS supply chain safety performance using inherent safety index system (ISI) is introduced. Recognizing the trade-offs between total cost, environmental impact reduction, and risk mitigation, our approach considers multi-objective optimization to concurrently address these sustainability objectives and generate a Pareto set of solutions. Utilizing the augmented ε-constraint method, we applied this framework to optimize CCUS networks and develop sustainable designs across three key objectives. The method was applied to a CCUS system that includes various CO2 utilization pathways to minimize the total annual cost, CO2 emissions, and safety risks. The resulting Pareto surface illustrates unique network configurations, each representing a distinct trade-off scenario. Through a case study, we optimized a CCUS network to achieve economic, environmental, and safety objectives. The most economically viable design, with a total annual cost of $97 million and a 40 % net carbon reduction, prioritizes CO2 utilization for value-added products, while limiting CO2 sequestration. Conversely, safety-focused designs shift utilization towards safer routes, including CO2 sequestration and algae production. The proposed framework offers a systematic approach to developing sustainable CCUS supply chain designs, balancing economic viability, environmental sustainability, and safety.

Mechanism analysis and performance comparison of extractive distillation with different extractants for separating methyl tert-butyl ether/methanol mixture

Methyl tert-butyl ether (MTBE) is an important chemical raw material and fuel additive commonly used in the chemical industry and can form minimum boiling azeotrope with methanol (MeOH). In this article, extractive distillation processes with common-extractant (diethylene glycol, DG), counter-extractant (chlorobenzene, CB) and ionic liquid ([MIM][HSO4]) for the separation of MTBE and MeOH binary azeotrope are investigated simultaneously for the first time. Moreover, five quantum chemical calculation methods of σ-profiles, electrostatic potential, interaction energy, Hirshfeld surface and weak interaction are used simultaneously for the first time to reveal the extractive distillation mechanism of different extractants in detail. Finally, three extractive distillation processes (CED-IL, CED-DG, CED-CB) are established and optimized with total annual costs (TAC) and CO2 emissions as objectives. Their performances are comprehensively compared from the aspects of economy, environment, energy, exergy and inherent safety under the optimal conditions. The results demonstrate that, in comparison to the CED-DG process, the CED-IL process reduces TAC by 31.0%, total energy consumption (TEC) and gas emissions by 27.7%, process route index (PRI) by 36.4% and increase thermodynamic efficiency by 46.4%, while the CED-CB process increases TAC by 29.1%, TEC and gas emissions by 23.2%, PRI by 22.1% and reduce thermodynamic efficiency by 11.4%.

A vapor phase side stream intensified extractive distillation process for separation of azeotropic mixture 2, 2, 2-trifluoroethanol and water

2,2,2-Trifluoroethanol (TFE) is an important organic fluoride with various commercial applications. During the production of TFE through hydrolysis, an azeotrope of TFE and water can form, making it challenging to separate using conventional distillation. This study proposes a novel approach employing vapor phase side stream intensified extractive distillation separation (VSED) with glycerol serving as an entrainer to address this challenge. Additionally, a dividing wall column process (DWC) is established. The total annual cost (TAC), CO2 emissions and total energy cost (TEC) of the proposed separation processes are calculated and compared. The results indicate that VSED process can recover TFE with a purity of 0.9995 (mole fraction). VSED exhibits a TAC reduction of 34.2 % and a CO2 emissions reduction of 33.9 % compared to the CED process. In addition, a dual-composition control strategy is proposed for the VSED process. The results show that control strategy can effectively cope with the feed flow perturbation of ±20 % and the feed composition perturbation of ±5 %.

Sustainable process design and multi-objective optimization of efficient and energy-saving separation of xylene isomers via extractive distillation based on double extractants

The focus of the chemical industry on environmental protection and energy conservation has driven the development of green distillation technology. Xylene isomers are extensively utilized industrial raw materials, whose separation is challenging and energy-intensive due to their closely similar boiling points. Therefore, it is urgent to develop energy-saving and environmental protection technology. In this paper, an energy-saving and environmental protection process for separating the xylene isomers by extractive distillation was designed combing the vapor recompression process with feed preheating (VRAPFP). The parameters of extractive distillation processes were synthetically optimized by multi-objective genetic algorithm (MOGA) with total annual cost (TAC), CO2 emission (ECO2) and separation efficiency (Eext) as the objective evaluation indexes. The economical optimal process was used further for VRAPFP design through heat integration to reduce energy consumption, and all the designed candidate processes were synthetically analyzed, compared and evaluated with performance indexes. Results show that the VRAPFP process has superior economic efficiency and ecological sustainability compared with the existing distillation process, wherein the TAC and ECO2 are reduced by 14.2 % and 30.2 %, respectively. This work provides a new reference and idea for separating xylene isomers with the economy and developing new processes for energy conservation and environmental protection.

Modeling and validation of multi-objective optimization for mixed xylene hybrid distillation/crystallization process

Innovative hybrid distillation/crystallization processes offer significant energy saving and cost reduction for the separation of isomer mixtures. Despite of the enormous potential of hybrid separation processes, they are not widely exploited in industrial applications due to the complexity of the design and multi-objective optimization of these highly integrated processes. In this study, the mixed xylene hybrid scheme was first simulated to provide the initial value of non-dominated sorted genetic algorithm-III. The operating parameters were then optimized through the Python-Aspen platform. Coupled with the online monitoring tool, a rigorous melt crystallization experiment was developed to track crystal size distribution (CSD) and crystal shape. By comparing the optimized results with the original ones, the total annual cost and CO2 emissions were, respectively, reduced by 5.35 % and 12.80 %. Through the experimental validation, the accuracy of the simulation-based crystallization CSD prediction method was discussed, and the potential and challenges of this novel method were proposed. This work aims to minimize the total annual cost and CO2 emissions of the mixed xylene hybrid process simultaneously and explore the feasibility of CSD prediction method by extracting two-dimensional crystal size information from online microscopic images.

Design and control of a novel multi-product extractive dividing wall column process for recycling organics from wastewater

The wastewater from a pharmaceutical plant consists of a tetrahydrofuran/isopropanol/water azeotrope. This investigation utilizes dimethyl sulfoxide as an extractant and employs an extractive dividing wall column to separate the aforementioned azeotrope. The extractive dividing wall columns are constructed with single, double, and triple partition walls, and a multi-objective genetic algorithm is used to optimize the operational parameters of the separation process. Of these columns, the extractive dividing wall columns with triple partition walls show the most favorable economic, environmental, and energy utilization performance, and it has a lower risk of combustion and explosion. Compared to the conventional design, the use of triple-partition extractive dividing wall columns results in a 22.13 % and 10.54 % reduction in total annual cost and CO2 emissions, respectively, and an increase in thermodynamic efficiency of 2.66 %. Studying the dynamic characteristics of this process reveals its excellent dynamic controllability.

Multi-Objective Optimization of an Energy Community Powered by a Distributed Polygeneration System

This paper presents a multi-objective optimization model for the integration of polygeneration systems into energy communities (ECs), by analyzing a case study. The concept of ECs is increasingly seen as beneficial for reducing global energy consumption and greenhouse gas emissions. Polygeneration systems have the potential to play a crucial role in this context, since they are known for producing multiple energy services from a single energy resource, besides the possibility of being fed also by renewable energy sources. However, optimizing the configuration and operation of these systems within ECs presents complex challenges due to the variety of technologies involved, their interactions, and the dynamic behavior of buildings. Therefore, the aim of this work is developing a mathematical model using a mixed integer linear programming (MILP) algorithm to optimally design and operate polygeneration systems integrated into ECs. The model is applied to a case study of an EC comprising nine buildings in a small city in the northeast of Italy. The work rests on the single- and multi-objective optimization of the polygeneration systems taking into account the sharing of electricity among the buildings (both self-produced and/or the purchased from the grid), as well as the sharing of heating and cooling between the buildings through a district heating and cooling network (DHCN). The main results from the EC case study show the possibility of reducing the total annual CO2 emissions by around 24.3% (about 1.72 kt CO2/year) while increasing the total annual costs by 1.9% (about 0.09 M€/year) or reducing the total annual costs by 31.9% (about 1.47 M€/year) while increasing the total annual CO2 emissions by 2.2% (about 0.16 kt CO2/year). The work developed within this research can be adapted to different case studies, such as in the residential–commercial buildings and industrial sectors. Therefore, the model resulting from this work constitutes an effective tool to optimally design and operate polygeneration systems integrated into ECs.

Novel integration and optimization of reliable photovoltaic and biomass integrated system for rural electrification

The novel concept of using hybrid renewable resources to provide clean energy helps to address the unique shortcomings of each renewable source. This study describes an innovative concept about the design of optimal grid PV/biomass 100 % renewable and fully reliable energy systems without considering energy storage devices. By leveraging community solar and biomass resources, the proposed system can power remote villages with a minimum cost of energy. Multi-Objective Genetic Algorithm (MOGA) is employed to perform an optimal procedure. The PV-biomass deployment project's economic viability is assessed using financial metrics such as net present cost (NPC) and cost of energy (COE). In order to install a hybrid system at the chosen site, the optimal configuration (PV 87 kW, biomass1 29 kW, and biomass2 125 kW) was examined. The NPC, COE, and total system cost, in this configuration, are $118,942, $0.02/kWh, and $892,892, respectively. The combined yearly consumption of the biomass1 and biomass2 generators is 704.81 tons of wheat straw. The total annual CO2 emissions of the PV, biomass1, and biomass2 generators in this system are avoided by 729.5 tons. The findings clearly demonstrate that the suggested approach can manage a reliable power flow with a suitable configuration. The solar PV and biomass system examined in this study will probably be a specialized solution in regions with abundant biomass resources; nevertheless, it offers a reliable starting point for the creation of larger-scale bioenergy value chains with the long-term objective of generating electricity from wheat straw biomass materials.

Soil respiration and its response to climate change and anthropogenic factors in a karst plateau wetland, southwest China.

It is important to investigate the responses of greenhouse gases to climate change (temperature, precipitation) and anthropogenic factors in plateau wetland. Based on the DNDC model, we used meteorological, soil, and land cover data to simulate the soil CO2 emission pattern and its responses to climate change and anthropogenic factors in Guizhou, China. The results showed that the mean soil CO2 emission flux in the Caohai Karst Plateau Wetland was 5.89 ± 0.17 t·C·ha-1·yr-1 from 2000 to 2019, and the annual variation showed an increasing trend with the rate of 23.02 kg·C·ha-1·yr-1. The soil total annual mean CO2 emissions were 70.62 ± 2.04 Gg·C·yr-1 (annual growth rate was 0.28 Gg·C·yr-1). Caohai wetland has great spatial heterogeneity. The emissions around Caohai Lake were high (the areas with high, middle, and low values accounted for 3.07%, 70.96%, and 25.97%, respectively), and the emission pattern was characterized by a decrease in radiation from Caohai Lake to the periphery. In addition, the cropland and forest areas exhibited high intensities (7.21 ± 0.15 t·C·ha-1·yr-1 and 6.73 ± 0.58 t·C·ha-1·yr-1, respectively) and high total emissions (54.97 ± 1.16 Gg·C·yr-1 and 10.24 ± 0.88 Gg·C·yr-1, respectively). Croplands and forests were the major land cover types controlling soil CO2 emissions in the Caohai wetland, while anthropogenic factors (cultivation) significantly increased soil CO2 emissions. Results showed that the soil CO2 emissions were positively correlated with temperature and precipitation; and the temperature change had a greater impact on soil respiration than the change in precipitation. Our results indicated that future climate change (increased temperature and precipitation) may promote an increase in soil CO2 emissions in karst plateau wetlands, and reasonable control measures (e.g. returning cropland to lakes and reducing anthropogenic factors) are the keys to controlling CO2 emissions.

Collaborative modeling and optimization of energy hubs and multi-energy network considering hydrogen energy

To achieve the goal of carbon neutrality, integrated energy hubs (EHs) based on coupled energy sources such as electricity, gas and heat are gaining increasing attention due to their efficient and flexible energy supply characteristics. The introduction of integrated EHs may lead to the reconstruction of the existing superior energy network to accommodate the suitable flow of the new network. In this study, a multi-objective optimization model is proposed that synergistically considers the optimal configuration of EHs and the reconstruction of higher-level energy networks, with the objectives of minimizing total annual energy supply costs and CO2 emissions. First, an EH and multi-energy network (MEN) topology model considering hydrogen energy is developed. Secondly, the joint output of wind and solar power under typical scenarios is sampled and obtained by employing the Monte Carlo sampling method and the synchronous back-propagation scenario analysis method. To address the nonlinear constraint problem associated with multi-energy storage output, the Big-M method is introduced to improve the optimization capability of spatial-temporal coupling of energy storage. Moreover, the utilization potential of hydrogen and renewable energy is explored by considering constraints on the nonlinear dynamic pricing of hydrogen. Finally, a numerical analysis is conducted using an illustrative example. The Pareto frontier optimal results, derived from fuzzy theory membership functions, are achieved using both classical and heuristic algorithms. The classical mixed-integer linear programming algorithm yields relatively superior optimization outcomes in terms of annual energy costs and carbon emissions compared to the heuristic algorithm. However, it suffers from longer computation times.

Energy-saving extractive distillation process for the separation of close-boiling 2, 6-xylenol and p-cresol mixture

1) Background2,6-xylenol and p-cresol are widely used in medicine synthesis, which are both important raw materials in chemical engineering. It is shown significant economic benefits to separate 2,6-xylenol and p-cresol. Owing to the extremely relative volatility between 2,6-xylenol and p-cresol, it is difficult to separate the two phenolic compounds through conventional distillation. 2) MethodsThe results of vapor–liquid equilibrium analysis, COSMO-SAC and reduced density gradient result are used to investigate molecular interaction in the separation system, indicating diethylene glycol (DEG) as the optimal solvent. Accordingly, we propose an energy-saving extractive distillation process with DEG as an efficient entrainer for the separation of 2,6-xylenol and p-cresol. Total annual cost (TAC) and CO2 emission are investigated for optimization and estimation of the proposed process. In addition, three energy-saving scenarios for further reductions in TAC and CO2 emission are proposed. 3) Significant FindingsCompared with the benchmark process, the TAC and CO2 emission of the energy-saving design vapor recompression heat pump assisted extractive distillation separation sequence B are reduced by 26.18 % and 49.18 %, respectively, which indicates that the considerable industrial potential of the proposed design.

Migration of transition metals and potential for carbon mineralization during acid leaching of processed kimberlite from Venetia diamond mine, South Africa

Carbonation of mafic and ultramafic rocks and mineral wastes provides a permanent way to sequester excess atmospheric CO2. Recent research has shown that this method also offers the potential for enhanced recovery of critical metals from mine tailings. In this study, processed kimberlite from the Venetia diamond mine (South Africa) was used in column acid leaching experiments to assess both its carbonation potential and whether critical metals such as nickel could be recovered during mineral carbonation. Processed kimberlite was treated daily with one pore volume of either deionized water or dilute hydrochloric acid (0.04 M, 0.08 M, 0.12 M and 0.16 M) for 28 days. Iron-rich yellow precipitates consistent with yellow ground formed during the experiments both at the top of the residue columns (corresponding to the inlets of the columns) and within the leachates collected from the bases of columns. The carbonation potential and mobility of transition metals were investigated using a combination of quantitative X-ray diffraction (XRD) using Rietveld refinements, inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDXS), transmission electron microscopy (TEM) coupled with EDXS, and synchrotron-based X-ray fluorescence microscopy (XFM). Our results show that the high proportion of clay minerals (e.g., lizardite, smectite, talc, chlorite) in the processed kimberlite act as the primary source for Mg and transition metals such as Ni; however, calcite dissolution is the main source for Ca. The amount of Mg and Ca extracted from processed kimberlite increases with HCl concentration. If acid leaching of processed kimberlite were used at Venetia, the amount of Mg leached from clay minerals would provide an estimated CO2 offset potential ranging from 2.1 to 15.8 % of the mine's total annual emissions. The leached Ca from silicate dissolution could also provide an estimated CO2 offset potential ranging from 2.1 to 8.1 % of the mine's total annual emissions. However, the amount of CO2 released by calcite dissolution during this process is equivalent to 2.1–14.3 % of total annual CO2 emissions at Venetia., thus resulting in a net estimated CO2 offset potential of 2.1–9.6 % if the Ca released from calcite could not be recarbonated. If all of the Ca could be reprecipitated as calcite, the acid leaching techniques employed in this study could offset 4.2–23.9 % of the Venetia mine's CO2 emissions. Ultimately, greater concentrations and/or amounts of acid may be used to access more of the offset potential of Mg phyllosilicates in kimberlite, but the CO2 released by calcite dissolution must also be won back by recarbonation.

Techno‐Economic Modeling of Diverse Renewable Energy Sources Integration: Achieving Net‐Zero CO2 Emissions

Integrating renewable energy sources (RES) into power systems presents significant challenges due to their diverse nature and operational characteristics. This study addresses these challenges through an innovative strategy that simulates solar and wind farms, storage systems, fuel cell generators of hydrogen energy (via electrolysis), and hydrogen storage, all governed by an intelligent controller. Alongside a mathematical model defining the system's dynamics, a multi‐objective optimization model is employed, exploring the system's operational, financial, and environmental impacts. While the mathematical model has limitations, the advanced model captures the system's dynamic behavior with exceptional precision. This intelligent simulation simplifies the complex interrelationships between various resources in the system, highlighting the viability of RES integration for enhanced benefits. Multi‐objective optimization of a real case study of Iowa 240‐Bus power system in the Midwest United States has resulted in an annual savings of $126 147.8, along with a significant CO2 reduction of 951 035.6 kg compared with the basecase. The total annual energy costs, including capital costs and electricity sales, are reported to be $157 430.4, and the total annual CO2 emissions are −4453.8 kg. Financial indicators highlight an annual cost reduction of 10.3% and an annual emission reduction of 100.5%. The simple and detailed project break‐even years are 18 and 1, respectively, with the project savings to cost minimization scenario ratio at 1.04. The optimization process efficiently handled a complex problem involving 5921 iterations, 299 247 variables, 11 854 discrete variables, and 342 167 equations, completing the entire operation in 12.7 s. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Partial heat-integrated reactive distillation process for producing n-propyl acetate using a heat exchanger network

ABSTRACT In this work, a partial heat-integrated reactive distillation process was studied to yield n-propyl acetate. To optimize the operating parameters of two distinct processes, the sequential iteration optimization method was employed. The heat exchanger network (HEN) is an effective approach for the heat-integrated design of a distillation process. Compared with the conventional reactive distillation process, the total annual cost, CO2 emissions and total energy consumption of the partial heat-integrated reactive distillation process decreased by 20.7%, 31.1%, and 32.2%, respectively. The thermodynamic efficiencies of reactive distillation process and partial heat-integrated reactive distillation process were 4.33% and 9.86%, respectively. The significance of this paper is crucial in guiding the process of partial heat-integrated reactive distillation for the production of n-propyl acetate.

Meat and Bone Meal as a Renewable Energy Source in Cement Kilns: Investigation of Optimum Feeding Rate

Meat and Bone Meal (MBM) is a CO2 neutral fuel, and hence is a good candidate for substituing fossil fuels like pulverized coal in rotary kiln burners used in cement kiln systems. MBM is used in several cement plants, but the optimum substitution rate has apparently not yet been fully investigated. The present study aims to find the maximum possible replacement of coal by MBM, without negatively affecting the product quality, emissions and overall operation of the process. A full-scale experiment was carried out in the rotary kiln burner of a cement plant by varying the MBM substitution rate from 0 to 7 t/hr. Clinker quality, emissions and other relevant operational data from the experiment were analysed. Additionally, coal and MBM were compared by laboratory experiments. The results revealed that MBM could safely replace more than 40% of the coal energy without giving negative effects. The limiting factor is the free lime content of the clinker. Possible explanations to the free lime increase are given. If 40% of the coal in the rotary kiln burner was replaced by MBM on a long-term basis, the total annual CO2 emissions of the plant could be reduced by 10%.