Total CO2 Emissions Research Articles

Province-Level Decarbonization Potentials for China's Road Transportation Sector.

Decarbonizing road transportation is an important task in achieving China's climate goals. Illustrating the mitigation potentials of announced policies and identifying additional strategies for various vehicle fleets are fundamental in optimizing future control pathways. Herein, we developed a comprehensive analysis of carbon dioxide (CO2) emissions from on-road vehicles as well as their mitigation potentials based on real-world databases and up-to-date policy scenarios. Total CO2 emissions of China's road transportation are estimated to be 1102 million tons (Mt) in 2022 and will continue to increase if future strategies are implemented as usual. Under current development trend and announced policy controls (i.e., integrated scenario), annual CO2 emissions are estimated to peak at 1235 Mt in 2025 and then decline to approximately 200 Mt around 2050. The scenario analysis indicates that electrification of passenger vehicles emerges as the most imperative decarbonization strategy for achieving carbon peak before 2030. Additionally, fuel economy improvement of conventional vehicles is identified to be effective for CO2 emission reduction for trucks until 2035 while new energy vehicle promotion shows great mitigation potentials in the long term. This study provides insight into heterogeneous low-carbon transportation transition strategies and valuable support for achieving China's dual-carbon goals.

Analysis of the Influence of Electricity Generation Mix on CO2 Emissions from Electric Vehicles in Europe

The rise in population mobility, with the dominant modal share of passenger vehicles, is particularly concerning due to its negative impact on the environment. Environmental issues caused by internal combustion engine (ICE) vehicles are increasing, as evidenced by the fact that road transport is responsible for 22% of total CO2 emissions. In this context, although electric cars do not emit harmful substances directly, power plants that generate electricity from various sources contribute significantly to these emissions. To determine the impact of electric vehicles on the environment, this study conducted a comparative analysis of gCO2/km emissions depending on the type of vehicle engine (petrol, diesel, and electric) across different European countries, based on their electricity sources. For more representative results, the comparison was made using the same make and model of car-Volkswagen e-Golf (electric car) and Golf 7 with diesel and petrol ICE engines. The results indicate that in Serbia, electric vehicles emit slightly less CO2 compared to diesel and petrol vehicles of similar characteristics. However, the difference is very small compared to diesel engines, amounting to only 3 gCO2/km.

Hydrogen vs. conventional sector-coupling residential energy systems: An economic and environmental comparison based on multi-objective design optimization

Planning residential energy systems faces economic, environmental, and technical challenges, necessitating cost-effective and environmentally friendly solutions. Hydrogen technologies in districts have recently gained interest. However, their economic and environmental potential relative to conventional technologies remains largely unexplored. Therefore, we quantitatively compared the impacts of designing hydrogen-based and conventional sector-coupling systems on total costs and CO2 emissions.We developed a multi-objective optimization model for the design and operation of generation and storage units, aiming to minimize total costs and CO2 emissions. We created three energy system configurations for an exemplary German district, each involving photovoltaics, heat storage, and batteries, while varying the main heat supplier. The first configuration includes a gas combined heat and power unit, the second features a heat pump, and the third incorporates a fuel cell, an electrolyzer, and hydrogen storage.Our comparison of the Pareto fronts revealed that the hydrogen system’s cost is 83% higher than the gas-based system and 33% higher than the heat-pump-based system. Environmentally, the hydrogen system emits 11% less than the gas-based system but 47% more than the heat-pump-based system. In conclusion, hydrogen units offer environmental benefits through improved photovoltaic utilization but perform poorly economically due to high investment and operating costs.

Assessment of Climate Change Mitigation Potential for Heating System in Kosovo

Objective: In this study is we have provided a prediction model for the improvement of heating system in Kosovo, following the implementation of an energy efficiency program, the consumption of energy commodities in heating system will decrease and the problem of deforestation will be mitigated. Theoretical Framework: We suppose a degree of reduction variable due to the renewable energy sources use, new technology options and energy efficiency toward GHG and air pollution reduction and policy initiative for District Heating in Kosovo. Method: For modelling impacts of the technology and policy options for reducing GHG and air pollution due to improvement of heating system in Kosovo, the model STELLA software has been used. Projection for emission factors and total annual emission for Air Pollutants and GHG (CO2) are calculated with US EPA methodology Results and Discussion: The resulting reductions of Air pollutants and greenhouse gas emissions by reducing the loss of heat and water and increasing the energy efficiency will have a direct and positive impact on the environment and climate change. Research Implications: Implementing the emission reduction policies EE, Renewable energy and introducing new technologies in heating system in Kosovo for the total emission of CO2, we will have reduction for about 20% (3.36 Mt CO2) in 2025 in comparison with (4.41 Mt CO2) in year 2015; also, we will have a significant reduction for other GHG. Originality/Value: This study contributes to the literature by impruvemment of heating system in Kosovo.

Life Cycle Assessment of Additively Manufactured Foundations for Ultratall Wind Turbine Towers

ABSTRACTWind energy production is rapidly growing in the United States and is expected to continue increasing as more and larger wind turbines are installed. To support these taller and heavier onshore turbines, new foundations must be designed and manufactured. One proposed method of reducing the total amount of concrete and steel in spread foundations is to utilize additive manufacturing to enable more material‐efficient designs. To compare these additively manufacturing‐enabled designs to conventional foundation designs, this study performs a life cycle impact assessment of four ultra‐tall wind turbine foundations: two foundations using 78‐MPa 3D printed stay‐in‐place concrete formwork cast with 35‐MPa ready‐mix concrete with reinforcements, and two conventional foundations cast entirely out of 35‐MPa concrete with reinforcements. The life cycle assessment investigates the environmental impacts of four different stages, including materials production, transportation, construction, and end‐of‐life. The materials production stage is found to dominate the life cycle results, contributing over 97% of the total CO2 emissions and over 88% of the fossil fuel depletion for each foundation. Compared to the conventional designs, the Short Flat Ribbed Beam foundation with 3D printed formwork has 22.4% lower CO2 emissions and 28.3% lower fossil fuel depletion than the Circular foundation, and 2.0% higher CO2 and 5.9% lower fossil fuel depletion compared to the Tapered foundation. Parametric studies indicate that reducing cement content and increasing recycled content in printed concrete can significantly reduce the overall life cycle impacts of the foundations.

Carbon emission scenario analysis of data centers in China under the carbon neutrality target

The low-carbon transformation of data centers is of great significance to achieve the goals of carbon peaking and carbon neutrality. This study compared and analyzed the overall situation of data centers in China. Based on China's CO2 emission and intensity targets in key years, the four variables of energy efficiency improvement rate, nonfossil energy consumption proportion, negative emission technology intensity, and waste energy utilization rate were introduced, and a net zero emission path model of data centers was established. Using scenario analysis to predict the total CO2 emissions and emission intensity from 2021 to 2060, three emission reduction path scenarios were obtained. Results showed that the energy consumption of data centers increased gradually, the carbon emissions first increased and then decreased, and the power usage effectiveness (PUE) of the data centers decreased gradually. The carbon peak time of the three scenarios is 2030, and the time for carbon neutrality is 2055, 2053, and 2051 in three scenarios. The data center industry should further improve the energy efficiency utilization rate, increase the proportion of nonfossil energy consumption, strengthen the technological innovation of carbon capture and storage, enhance the level of carbon sink, and optimize the utilization rate of waste energy.

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.

Sustainable Decarbonization of Road Transport: Policies, Current Status, and Challenges of Electric Vehicles

Carbon dioxide (CO2) and other greenhouse gases (GHGs) are the primary causes behind the current rise in global temperatures and climate change. CO2, which is present in the atmosphere in significant quantities, is contributing more to the warming effect than other gases that are present at smaller levels. The transportation sector is contributing significantly to the total global CO2 emissions (21.7%), with road transport accounting for 74%. Switching from gasoline-powered vehicles to electric vehicles (EVs) is the most practical way to decarbonize land transportation. We have gathered information on EVs from the USA, China, India, and a few EU members for the current review. The collected data regarding government policies, subsidies, and other rules and laws, the present status of EV technology and performance, market scenarios and future projections of EVs, EV regulations in the regions with the highest penetration rates, consumer perspectives and barriers, and the decarbonization of land transportation were analyzed. The adoption of electric vehicles has advanced significantly in some parts of the world, primarily as a result of government policies that include subsidies, other regulations, and laws that globally lower the cost of acquisition and ownership for owners of electric vehicles (EVs) relative to those of internal combustion engines (ICEs). Favorable government policies have been associated with the success of EV adoption in Norway, China, the United States of America (USA), the European Union (EU), and India. With more advantages than any other country, China is currently the world’s largest EV market. In addition, it has the highest number of EVs in use and the highest manufacturing capacity. Norway leads the world in the percentage of newly registered EVs at over 90%. China is competing with the USA for leadership in manufacturing and technology, especially in the areas of artificial intelligence (AI) and batteries. Favorable perceptions of consumers regarding EVs are vital in increasing the EV adoption rate. In order to achieve the goal of decarbonizing road transportation, we proposed that a number of factors—including government energy policies and regulatory standard development, necessary infrastructure investments and developments, AI incorporation in EVs, innovation in EV and battery technologies, and consumer perspectives in particular—play a crucial role.

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.

An analysis of the impact of CO2 emissions from deforestation and mining in Madre de Dios, Perú

The Madre de Dios Region of Peru faces significant deforestation largely due to a surge in artisanal-small scale gold mining (ASGM), propelled by rising gold prices. This study evaluates the full scope of ASGM activities on net CO2 emissions, accounting for both the deforestation that converts forests into mining territories and the emissions directly resulting from mining and transportation activities. By applying kriging to a comprehensive dataset, we determined the carbon content of the region and the annual loss of CO2 capture due to deforestation. Our analysis also incorporates emissions from the Interoceanic highway, which has contributed to the mining boom. The findings indicate a total net CO2 emission of 429.9 Gigagrams (Gg) per year, underscoring the critical environmental challenge these activities pose. Our study highlights the need for immediate and effective reclamation efforts, including reforestation with indigenous carbon-rich trees, as a counterbalance to the environmental damage inflicted. These efforts are essential to mitigate the adverse impacts and support the global movement towards net-zero emissions.

Coke breeze combustion and emission behaviors of CO and NO during iron ore sintering

CO emission reduction, especially the coordinated emission reduction of CO and NO in sintering flue gas, has attracted widespread attention in the world. The effects of different sintering raw materials, temperature and atmosphere on coke breeze combustion and CO and NO emission behaviors were studied. The results show that, sintering raw materials significantly improved the combustion performance of coke breeze, and promoted the simultaneous reduction of CO and NO emissions. Among them, Dolomite had the strongest catalytic effect, which reduced the apparent activation energy of coke breeze combustion reaction from 99.35 kJ/mol to 56.11 kJ/mol, and the emission reductions of CO and NO were as high as 47.84 % and 73.25 %, respectively. The catalytic ability of the raw materials components was CaO ＞ MgO ＞ Fe2O3. However, during the combustion process of coke breeze without raw materials, the reduction of NO by CO was affected by the atmosphere of the boundary layer, the conversion of N element was negatively correlated with the content of CO. When the temperature increased from 600 ℃ to 1 050 ℃, the combustion performance was improved, the thickness of the combustion zone was reduced by 47.92 %, the total emission of CO was decreased by 65.39 %, and the total emission of NO was increased by 23.05 %. The O2 concentration decreased from 21 % to 10 %, the combustion rate decreased, the combustion zone thickened by 90 %, incomplete combustion was promoted, the total emission of CO increased by 101.15 %, and NO decreased by 21.09 %. The CO2 concentration increased from 5 % to 15 %, the gasification reaction was enhanced, the combustion time was extended, the combustion zone thickened by 45.9 %, the total emission of CO increased by 87.12 %, and the reducing atmosphere was enhanced, which was conductive to the reduction of NO by CO, and the total emission of NO decreased by 50.59 %.

Energy efficiency and greenhouse gas emissions: A panel ARDL model of top five emitters in Africa

The Paris Agreement has mandated drastic decarbonization by developed and developing economies. Many of the top African emitters are now exploring drastic restructuring of the production processes in a way that promotes energy utilization efficiency. This is critical for ensuring an environmentally benign growth process. This study presents a unique addition to the body of existing knowledge by analysing the effect of some indicators of energy efficiency on three indicators of environmental quality among the top five emitters of GHG in Africa. The data were from the World Development Indicators (WDI), covering the 1990–2020 periods for South Africa, Egypt, Nigeria, Algeria, and Libya. The panel Autoregressive Distributed Lag (ARDL) model was used for data analysis. The results showed that all the included series were stationary at first difference. The optimum lag lengths were determined independently in STATA 17 software, and the most frequent lags across the countries were selected. The Hausman test revealed that the pooled mean group (PMG) estimation was preferred to other estimators. The results showed that in the long-run, particulate emission damages, CO2 intensity, and energy use intensity positively impacted GHG emissions, while GDP per capita and renewable energy utilization produced mixed results. In the short run, the error correction mechanism parameters were all significant (p < 0.01) in Libya for all emission indicators, while Algeria showed significance (p < 0.01) in total GHG and CO2 per capita models. The coefficient of particulate emission damages significantly reduced (p < 0.01) total GHG emissions in Libya and Nigeria and renewable energy significantly increased (p < 0.01) GHG emissions in South Africa but reduced them in Nigeria. Also, CO2 emission intensity significantly (p < 0.01) and positively impacted GHG emissions in South Africa, Egypt, Libya, and Nigeria, while electricity power transmission losses increased total emissions and CO2 emissions in Libya and Algeria. It was concluded that initiatives to reduce GHG emissions should focus on developing countries’ sensitivity to emission damages, and promotion of initiatives for using renewable energies. Also, promotion of energy efficiency across industries offers a prospect for ensuring environmental sustainability.

Heat-integrated extractive distillation for separating tetrahydrofuran/methanol/water with ionic liquid-based mixed entrainer: Molecular mechanism and process integration

Tetrahydrofuran (THF) and methanol (MeOH) are commonly used raw materials and reagents in the chemical industry, but the azeotropic phenomenon between the two components makes it challenging to achieve high-purity separation. This study separated THF/MeOH/H2O mixtures by heat-integrated extractive distillation using an ionic liquid-based mixed entrainer (ILME). The dimethyl sulfoxide (DMSO) was determined by relative volatility analysis, and IL [EMIM][AC] was screened from 240 ionic liquids according to the COSMOtherm 2021 software. The separation mechanism was investigated at the molecular level (i.e., IGM analysis, polarisation charge density (σ-profile), electrostatic potential (ESP), interaction energy, and quantum chemical theory), which demonstrated that the rationality and strength of the interaction between the entrainer and the separated system were conducive for the separation to proceed. Single DMSO, ILME indirect extractive distillation (IED) and direct extractive distillation (DED) were designed and optimized, and further heat-integrated optimization (HI-DED) was performed on the ILME direct extractive distillation process. The results showed that HI-DED reduced the average annual total energy consumption, energy utilization and CO2 emissions by 23.23%, 26.24% and 26.24%, respectively, compared to the conventional direct extraction distillation process. The HI-DED process using ILME significantly reduces economic, energy consumption and CO2 emissions compared to conventional extractive distillation and has great potential for industrial applications.

Progressive melting of surface water and unequal discharge of different DOM components profoundly perturb soil biochemical cycling

Freeze-thaw (FT) events profoundly perturb the biochemical processes of soil and water in mid- and high-latitude regions, especially the riparian zones that are often recognized as the hotspots of soil-water interactions and thus one of the most sensitive ecosystems to future climate change. However, it remains largely unknown how the heterogeneously composed and progressively discharged meltwater affect the biochemical cycling of the neighbor soil. In this study, stream water from a valley in the Chinese Loess Plateau was frozen at –10°C for 12 hours, and the meltwater (at +10°C) progressively discharged at three stages (T1 ∼ T3) was respectively added to rewet the soil collected from the same stream bed (Soil+T1 ∼ Soil+T3). Our results show that: (1) Approximately 65% of the total dissolved organic carbon and 53% of the total NO3--N were preferentially discharged at the first stage T1, with enrichment ratios of 1.60 ∼ 1.94. (2) The dissolved organic matter discharged at T1 was noticeably more biodegradable with significantly lower SUVA254 but higher HIX, and also predominated with humic-like, dissolved microbial metabolite-like, and fulvic acid-like components. (3) After added to the soil, the meltwater discharged at T1 (e.g., Soil+T1) significantly accelerated the mineralization of soil organic carbon with 2.4 ∼ 8.07-folded k factor after fitted into the first-order kinetics equation, triggering 125 ∼ 152% more total CO2 emissions. Adding T1 also promoted significantly more accumulation of soil microbial biomass carbon after 15 days of incubation, especially on the FT soil. Overall, the preferential discharge of the nutrient-enriched meltwater with more biodegradable DOM components at the initial melting stage significantly promoted the microbial growth and respiratory activities in the recipient soil, and triggered sizable CO2 emission pulses. This reveals a common but long-ignored phenomenon in cold riparian zones, where progressive freeze-thaw can partition and thus shift the DOM compositions in stream water over melting time, and in turn profoundly perturb the biochemical cycles of the neighbor soil body.

Carbon budgets of lakes on the Tibetan Plateau: Highlighting non-negligible carbon emissions from small lakes

The release of carbon dioxide (CO2) from lakes is a critical element of carbon (C) emissions from inland waters. Within the realm of climate change, the inquiries surrounding whether lakes on the Tibetan Plateau (TP) function as C sources or sinks and the magnitude of CO2 exchange flux from these lakes have garnered significant attentions. Nevertheless, accurately assessing the lakes’ contribution to the C budgets poses challenges due to data scarcity and methodological inaccuracies. By amalgamating data from literature reviews and field measurements for different sizes of lakes during the ice-free (IF) and ice-covered (IC) periods from 2016 to 2021, this study offers a refined estimate of the CO2 exchange flux and flux rate for lakes on the TP by including lakes ranging in size from 0.01 to 1 km2 (small lakes) in the C budgets. Findings revealed that the annual CO2 exchange flux of TP lakes amounted to 7.10 Tg C yr–1, with 6.56 Tg C yr–1 and 0.54 Tg C yr–1 during the IF and IC periods, respectively. Notably, small lakes contributed 0.76 Tg C yr–1, representing 10.65 % of the total lake CO2 emissions on the TP, which indicates the significant role of small lakes in estimating CO2 emissions from TP lakes. The CO2 exchange fluxes of small lakes showed significant variability during the IF period, with the origins of lake water replenishment possibly explaining this diversity, where glacial meltwater replenishment is likely a key contributing factor. In contrast, CO2 emissions from small lakes increased during the IC period. The view of this study is that the groundwater recharge with higher CO2 concentrations and the shallow nature of small lakes may be the main reasons for the increase in CO2 emissions from small lakes during this period. The study underscores that the contribution of small lakes to the CO2 budgets of TP lakes is substantial and warrants attention, particularly in elucidating the mechanisms driving CO2 emissions from small lakes.

A Two-Echelon Routing Model for Sustainable Last-Mile Delivery with an Intermediate Facility: A Case Study of Pharmaceutical Distribution in Rome

This paper introduces a two-echelon optimization model for the integrated routing of an electric vehicle (EV) and a traditional internal combustion engine vehicle (ICEV) in an urban environment. The scientific context of this study is sustainable urban logistics. The case study focuses on the distribution of pharmaceuticals in the metropolitan area of Rome. Distributing pharmaceuticals in large cities presents significant challenges, including heavy traffic congestion, the need for strict temperature control, and the maintenance of the integrity and timely delivery of sensitive medications. Furthermore, the complexity of urban logistics and adherence to regulatory requirements introduce additional layers of difficulty. Therefore, the implementation of fast and sustainable distribution mechanisms is crucial in this context. Specifically, the model seeks to minimize both total CO2 emissions and transportation costs while optimizing the use of an EV and an ICEV, all while ensuring that service level requirements are met. Computational results demonstrate the effectiveness of the proposed method in improving the sustainability of pharmaceutical distribution.

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%.

Life Cycle Carbon Assessment of Mortars with Carbonated and Non-Carbonated Recycled Aggregates

Global warming is one of the most important issues that the world is currently facing. The cement industry accounts for around 7% of total global CO2 emissions. According to the 13th United Nations Sustainable Development Goals, cement plants must become carbon neutral by 2050. This neutrality may be achieved by a reduction in CO2 emissions complemented with carbon capture, utilization and storage (CCUS) technologies. In accordance with these sustainable goals, several approaches have been studied. This paper investigates life cycle carbon of mortars produced with carbonated recycled aggregates. In previous works, the carbon dioxide capture capacity of construction and demolition waste (CDW) was analysed, and mortars with CDW recycled aggregates submitted to high levels of CO2 were evaluated in terms of their mechanical performance. This paper focus on the life cycle carbon impact assessment (LCCA) of industrial mortar formulations in a cradle-to-gate boundary. This assessment is carried out through a global warming potential environment impact assessment, since it represents the amount of CO2 equivalent that is sent to the atmosphere and contributes to the “greenhouse effect”. This LCCA includes the impacts associated with the treatment and additional transportation routes of the recycled aggregates. With this work, it was found that mortars with carbonated recycled aggregates have a considerably lower global warming potential impact than mortars without recycled aggregates. The mortars with recycled aggregates presented lower CO2 emissions of up to 6.31% for 100% incorporation of non-carbonated recycled aggregates. These values were incremented with the carbonation of the recycled aggregates, achieving a reduction of CO2 emissions of up to 36.75% for 100% of incorporation.

Carbon emission drivers of China's power sector and its transformation for global decarbonization contribution

To explore the contribution of China's power sector transformation to global CO2 emission reduction and the potential for this sector to achieve peak carbon, we used a hybrid input–output model to explore the direct CO2 emissions of six power sectors classified by generation methods and their impact on CO2 emission by the non-power sector based on the total power sector output (electricity generation). We then used structural decomposition analysis to explore the drivers. From 2012 to 2021, the total indirect CO2 emissions of China's power sector grew from 138.59 Mt to 158.79 Mt (the share in the carbon footprint increased from 3.7% to 3.9%), an increase of 14.6%. Over the period from 2012 to 2021, the power structure effect consistently reduced direct and indirect CO2 emissions. Policy scenario simulations showed that 12 scenarios for 2035 are expected to achieve peak carbon in China's power sector. The transition of China's power sector to cleaner energy will contribute greatly to global CO2 reduction in all sectors. In scenarios APS-DER-LD and APS-DER-HD, where the power structure effect was strongest, China and other countries will simultaneously experience large decreases in carbon emission, with decreases of 43.5 and 36.6%, respectively.