Valorization of coal gasification slag via Fischer-Tropsch tail gas driven calcination: Hydration mechanisms, life cycle sustainability and heavy metal leaching assessment of composite cement.

Sustainable valorization of coal gasification slag through optimized grinding kinetics: Composite cement compressive strength enhancement and environmental assessment.

Sustainable application of waste residue from coal gasification process in low-carbon cement: multiscale evaluation, hydration behavior, mechanical performance, and environmental assessment.

Large-scale application of coal gasification slag in nonburnt bricks: Hydration characteristics and mechanism analysis

Gasification slag is a solid waste generated by the coal chemical industry which has emerged in recent years. In this paper, the effect of coal gasification slag (CGS) powder content on the reaction kinetics, gel structure and the compressive strength of Portland cement was investigated for the potential application of CGS powders in cementitious materials. The reaction and gel structure of Portland cement blended with CGS was analyzed by using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy tests. The results show that the unreacted CGS power exists mainly in an agglomerated state in cement matrix, and a low dosage of CGS powder (10%) can play a role in nucleation and pozzolanic effect in Portland cement, which is conducive to the formation of hydration reactions of Portland cement, shortening the setting time and improving the compressive strength. If the CGS content is >30%, the hydration product content decreases, and the microstructure of the sample becomes loosened. The setting times are significantly prolonged with the increase of CGS content dosing and the compressive strength is considerably reduced as well.

Utilization of coal gasification slag produced in the process of converting coal into combustible gas in cement: Multiscale evaluation, mechanistic analysis, and environmental impacts

The role of coal gasification slag in cement paste with and without polycarboxylate superplasticizer and its rheology

The impact of CO2 uptake rate on the environmental performance of cementitious composites: A new dynamic Global Warming Potential analysis

Different grazing management strategies change greenhouse gas emissions and global warming potential in global grasslands

Greenhouse gas (GHG) emissions from biomass combustion include carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), which cause climate change and global warming. By measuring GHG emissions by biomass combustion, a potent protocol for the calculation of global warming potential (GWP), which is how much the global temperature has risen due to combustion processes, can be achieved, contributing to determining the mean reduction in global temperature rise and fostering a transition towards more sustainable energy systems. Additionally, warning can be given of the GHG and GWP risks associated with different species of biomass. This review includes the GHG emissions and GWP of biomass combustion and their measurement and estimation directly through biomass sample combustion, using unmanned aerial vehicles (UAVs) and satellite measurements of radiation interacting with atmospheric gases, or satellite-derived data and calculations according to IPCC guidelines. In addition, the relationship of lignocellulosic compounds and elements in biomass to HHV and GHG emissions is described. The key mechanism of molecular vibration of hydrogen bonds in biomass caused by NIR radiation related to GHG emissions is revealed and recorded regarding the possibility of using NIR spectroscopy for the prediction of GHG emissions and GWP. Calculation examples for sugarcane bagasse and other biomass species are shown. The comparative advantages and limitations of NIR spectroscopy with respect to other methods are included. These factors lead to elucidation of the possibility of using NIR spectroscopy for non-destructive prediction of GHG emissions. In this review, the feasibility of using NIR spectroscopy to evaluate GHG emissions, GWP and emission factors (EFs) as an alternative to IPCC estimation methods related to climate change by biomass combustion is confirmed. NIR spectroscopy is a novel methodology for predicting GHG emissions and GWP directly from intact chip or powder biomass spectral data without explicit gas measurement. This article records the essential spectroscopic knowledge of biomass polymer valorization that is of value in polymer science.

Coal gasification slag is an inevitable by-product of the coal gasification process. This paper explored the feasibility of using activators (calcium hydroxide, sodium hydroxide, calcium sulfate, sodium sulfate) to promote the pozzolanic activity of milled coal gasification coarse slags (MCS), and analyzed the effect of alkali and sulfate activators on the hydration characteristic of cement-based materials containing MCS. Coal gasification slags with ignition lossses more than 15% were removed and the remaining slags were considered as cementitious material after milling. Scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and hydration heat tests were employed to analyze the hydration mechanism of the samples. Besides, the compressive strength values of cement mortars with MCS and activators were evaluated. The results showed that calcium hydroxide was conductive to the formation of hydration products and its crystallization could contribute to the strength improvement of the sample. Calcium sulfate mainly participated in the hydration process of cement to form ettringite (AFt) phases. Sodium hydroxide could accelerate the dissolution of active mineral phases of MCS, resulting in the pozzolanic activity being enhanced. Moreover, sodium sulfate could not only increase the formation of AFt phases, but also improved the alkalinity in sample to facilitate the production of gels. Among them, a better promotion effect could be obtained from the combined application of calcium hydroxide and sodium sulfate. In addition, the compressive strength values of cement mortars containing MCS tended to increase when activators were used. The sample activated by calcium hydroxide and sodium sulfate exhibited the highest strength, increasing by 18.55% at 28 days compared with the sample without an activator.

Exploring lifecycle energy and greenhouse gas emissions of a case study with ambitious energy compensation goals in a cooling-dominated climate

The impact of organic fertilizer replacement on greenhouse gas emissions and its influencing factors

The addition of graphene oxide (GO) to cement-based materials can improve their mechanical performance and durability. However, there are few direct comparisons between different binder systems. While GO has been widely studied in Portland cement (PC), its effect on alternative binders like magnesium oxychloride cement (MOC) has usually been explored separately and under different experimental conditions. This study offers a direct comparison of GO-modified PC and MOC composites, with both prepared and tested under the same conditions. Composites containing up to 1.0 wt% GO were assessed using XRD, SEM, EDS, XRF, MIP, and thermal analysis, as well as mechanical and hygric testing. The results indicate that GO does not change the basic phase structure of either binder system but leads to different responses based on the system. Flexural strength increased by as much as 17.6% in PC and 13.4% in MOC composites. Compressive strength showed an optimal level at moderate GO amounts but declined at higher levels. Water absorption and transport were slightly lower, especially with increased GO amounts. In MOC composites, water resistance improved, shown by higher softening coefficients and retained compressive strength. Thermal conductivity and volumetric heat capacity increased with more GO content. These findings show that GO's effect varies with the type of binder. In hydration-based PC systems, its impact mainly appears in microstructure and mechanical response. In crystallization-based MOC systems, changes in water performance are more noticeable. The study offers a controlled comparison that aids in designing GO-modified cement-based materials for specific engineering uses. • GO effects compared in PC and MOC binding systems. • Strength controlled by pore redistribution and GO dispersion. • Non-linear porosity–strength relationship demonstrated. • Moisture transport linked to capillary connectivity changes. • Thermal response explained by competing porosity and GO effects.

Core Ideas Elevated O3 (EO3) effects on GHG flux and GWP from O3‐sensitivity wheat systems were studied.EO3 reduced belowground biomass of O3‐sensitive (SW) and O3‐tolerant (TW) wheat cultivars.O3‐sensitivty of wheat cultivar affected responses of gaseous C and N emission and GWP to EO3.SW wheat would release more freshly assimilated C, adding GHG emission and GWP under EO3. The effects of elevated O3 (EO3) on greenhouse gas (GHG) emissions and global warming potential (GWP) from wheat systems with differential O3 sensitivity are not well understood. The nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2) emissions from cropping (CP) and bare soil or root‐free (BS) plots, GWP, GWP per unit yield, and biomass and its allocation to belowground between O3‐sensitive (cultivar YN19) and tolerant (cultivar Y15) wheat (Triticum aestivum L.) systems were investigated at EO3 and ambient O3 (AO3) with an open‐air O3 fumigation system. Results indicated that a 50% elevation above AO3 significantly reduced belowground biomass of the two cultivars. The EO3 significantly increased the cumulative emissions of CO2 and N2O but did not change that of CH4 in YN19 CP. For BS, it significantly increased the emission of CO2 but decreased that of CH4 and N2O. The EO3 significantly increased the GWP and GWP per unit yield in YN19 CP but reduced the GWP in BS. The O3 sensitivity of wheat cultivar affected the responses of gaseous C and N emission, GWP and GWP per unit yield to EO3. The O3‐sensitive wheat cultivar would release more freshly assimilated C, increasing cumulative GHG emissions, GWP and GWP per unit yield in response to O3 stress, when compared to the O3 O3‐tolerant wheat cultivar. Our results suggest that EO3 may impair soil C and N sequestration in an O3 O3‐sensitive wheat–soil system in view of lower root biomass but higher CO2 and N2O emissions under EO3.

Beef cattle production is an important contributor to global warming both nationally and globally. Through a national life cycle assessment, we have determined that the production of beef cattle in the U.S. produces about 243 Tg of carbon dioxide equivalents (CO2e) in global warming with an intensity of 21 kg CO2e/kg of carcass weight. This is about 3.5% of the national inventory of greenhouse gas (GHG) emissions. Globally, the Food and Agriculture Organization (FAO) estimates the direct GHG emissions from all cattle other than dairy and their manure to be about 2,260 Tg or about 4.5% of the total global GHG emission. An important consideration in calculating the contribution of beef cattle is the assumed global warming potentials (GWP) used to relate the warming effect of methane and other compounds to that of CO2. Recommended values have varied over the past 20 years as we learn more about the warming potential of various gases. Values assumed affect published assessments, so it is important to consider the GWP values used when comparing studies. Methane is unique among the major compounds affecting global warming because it has a relatively short life in the atmosphere (half-life of about 8 years). Methane released by cattle and their manure oxidizes in the atmosphere returning the carbon originally fixed by growing plants back to CO2 completing a natural cycle. To better represent the warming effect of methane in the atmosphere, a model called GWP* has been introduced. To use this model, the change in emission rate over time must be quantified. Compared with 50 years ago in the U.S., we are now producing 20% more meat using about 15% fewer cattle. We estimate that the GHG intensity in cattle production has decreased 34%, and the total GHG emission related to beef cattle production has decreased 21% over this period. Considering the change that has occurred, using the GWP* model reduces the global warming impact of U.S. beef cattle by over 50% relative to the use of the commonly accepted current GWP factors. Global change is more difficult to quantify. The FAO estimates that over the past 50 years, the global number of non-dairy cattle has increased about 39% with a 78% increase in meat production and 36% increase in related methane emissions. Applying these data indicates that use of the GWP* model decreases the warming effect of global cattle by about 20%. When making policy decisions to mitigate GHG emissions, it is important to properly represent the relative warming effect of the important greenhouse gases.