Assessment of the Suitability of Coke Material for Proppants in the Hydraulic Fracturing of Coals

To enhance the extraction of methane gas from coal beds, hydraulic fracturing technology is used. However, stimulation operations in soft rocks, such as coal beds, are associated with technical problems related mainly to the embedment phenomenon. Therefore, the concept of a novel coke-based proppant was introduced. The purpose of the study was to identify the source coke material for further processing to obtain a proppant. Twenty coke materials differing in type, grain size, and production method from five coking plants were tested. The values of the following parameters were determined for the initial coke: micum index 40; micum index 10; coke reactivity index; coke strength after reaction; and ash content. The coke was modified by crushing and mechanical classification, and the 3-1 mm class was obtained. This was enriched in heavy liquid with a density of 1.35 g/cm³. The crush resistance index and Roga index, which were selected as key strength parameters, and the ash content were determined for the lighter fraction. The most promising modified coke materials with the best strength properties were obtained from the coarse-grained (fraction 25-80 mm and greater) blast furnace and foundry coke. They had crush resistance index and Roga index values of at least 44% and at least 96%, respectively, and contained less than 9% ash. After assessing the suitability of coke material for proppants in the hydraulic fracturing of coal, further research will be needed to develop a technology to produce proppants with parameters compliant with the PN-EN ISO 13503-2:2010 standard.

Manufacture of SiC: Effect of Carbon Precursor

SiC is one of the most important ceramics at present due to its excellent properties and wide range of applications. The industrial production method, known as the Acheson method, has not changed in 125 years. Because the synthesis method in the laboratory is completely different, laboratory optimisation may not be extrapolated to the industrial level. In the present study, the results at the industrial level and at the laboratory level of the synthesis of SiC are compared. These results show that it is necessary to make a more detailed analysis of the coke than the traditional one; therefore, the Optical Texture Index (OTI) should be included, as well as the analysis of the metals that form the ashes. It has been found that the main influencing factors are OTI and the presence of Fe and Ni in the ashes. It has been determined that the higher the OTI, as well as the Fe and Ni content, the better the results obtained. Therefore, the use of regular coke is recommended in the industrial synthesis of SiC.

Modeling of Polymer Composite Materials Chaotically Reinforced with Spherical and Cylindrical Inclusions

The technical and economic efficiency of new PCMs depends on the ability to predict their performance. The problem of predicting the properties of PCMs can be solved by computer simulation by the finite element method. In this work, an experimental determination of the physical and mechanical properties of PTFE PCMs depending on the concentration of fibrous and dispersed filler was carried out. A finite element model in ANSYS APDL was built to simulate the strength and load-bearing capacity of the material with the analysis of damage accumulation. Verification of the developed computer model to predict the mechanical properties of composite materials was performed by comparing the results obtained during field and model experiments. It was found that the finite element model predicts the strength of chaotically reinforced spherical inclusions of composite materials. This is due to the smoothness of the filler surfaces and the lack of filler dissection in the model. Instead, the prediction of the strength of a finite element model of chaotically reinforced cylindrical inclusions of composite materials requires additional analysis. The matrix and the fibrous filler obviously have stress concentrators and are both subject to the difficulties of creating a reliable structural model.

Induction Heating of Magnetically Susceptible Nanoparticles for Enhanced Hydrogenation of Oleic Acid

Radio frequency (RF) induction heating was compared to conventional thermal heating for the hydrogenation of oleic acid to stearic acid. The RF reaction demonstrated decreased coke accumulation and increased product selectivity at comparable temperatures over mesoporous Fe₃O₄ catalysts composed of 28-32 nm diameter nanoparticles. The Fe₃O₄ supports were decorated with Pd and Pt active sites and served as the local heat generators when subjected to an alternating magnetic field. For hydrogenation over Pd/Fe₃O₄, both heating methods gave similar liquid product selectivities, but thermogravimetric analysis-differential scanning calorimetry measurements showed no coke accumulation for the RF-heated catalyst versus 6.5 wt % for the conventionally heated catalyst. A different trend emerged when hydrogenation over Pt/Fe₃O₄ was performed. Compared to conventional heating, the RF increased the selectivity to stearic acid by an additional 15%. Based on these results, RF heating acting upon a magnetically susceptible nanoparticle catalyst would also be expected to positively impact systems with high coking rates, for example, nonoxidative dehydrogenations.

Functioning of Heat Accumulating Composites of Carbon Recyclate and Phase Change Material

The article presents the results of experimental research together with the development of a response function presenting the thermal functioning of a new composite of a phase change material with carbon recyclate. The empirical research proved the improvement of the thermal functioning of the phase change material as a result of modifying its structure with carbon-based recycling material. The conducted experimental tests and statistical analysis proved that the obtained innovative composite is characterized by a more effective distribution of stored heat than the pure phase change material, which resulted in reduction of the heating and cooling time of the package by 10 min. The obtained innovative composite can improve the thermal efficiency of short-term heat storage systems, both in building components and in elements of heating and cooling systems, and translates into their increase in thermal efficiency.

Effect of Preparation Method on the Catalytic Performance of HZSM-5 Zeolite Catalysts in the MTH Reaction

A kind of nano-ZSM-5 zeolite crystal was synthesized by the hydrothermal method, and HZSM-5 zeolite powder was obtained via acid exchange. By using pseudoboehmite as a binder, a series of HZSM-5 zeolite catalysts for methanol-to-hydrocarbons (MTH) were prepared through adjusting the binder content between 20 and 50% in addition to the molding method of wet extrusion and mechanical mixing. XRD, ²⁷Al NMR, SEM-EDS, ICP, low-temperature N₂ adsorption and desorption, NH₃-TPD, Py-FTIR, FT-IR, TG and elemental analyses were used to characterize the properties of fresh catalysts and coke-deposited catalysts. Then, MTH catalytic performance was evaluated in a continuous-flow fixed-bed reactor. The characterization and evaluation results showed that the addition of dilute nitric acid during the molding process increased the amount of moderate-strength acid and formed a hierarchical pore distribution, which helped to reduce the reaction ability of cracking, aromatization and hydrogen transfer, improve the diffusion properties of the catalyst and slow down the coke deposition rate. The catalyst with a binder content of 30% made by wet extrusion with dilute nitric acid had the best performance, whose activity stability of MTH increased by 96 h, higher than other catalysts, and the coke deposition rate was slower, which was due to the most suitable distribution of acid strength and B/L ratio as well as the most obvious hierarchical pore structure.

Metallurgical Coke Production with Biomass Additives: Study of Biocoke Properties for Blast Furnace and Submerged Arc Furnace Purposes

Biocoke has the potential to reduce the fossil-based materials in metallurgical processes, along with mitigating anthropogenic CO₂- and greenhouse gas (GHG) emissions. Reducing those emissions is possible by using bio-based carbon, which is CO₂-neutral, as a partial replacement of fossil carbon. In this paper, the effect of adding 5, 10, 15, 30, and 45 wt.% biomass pellets on the reactivity, the physicomechanical, and electrical properties of biocoke was established to assess the possibility of using it as a fuel and reducing agent for a blast furnace (BF) or as a carbon source in a submerged arc furnace (SAF). Biocoke was obtained under laboratory conditions at final coking temperatures of 950 or 1100 °C. Research results indicate that for BF purposes, 5 wt.% biomass additives are the maximum as the reactivity increases and the strength after reaction with CO₂ decreases. On the other hand, biocoke’s physicomechanical and electrical properties, obtained at a carbonization temperature of 950 °C, can be considered a promising option for the SAF.

A Simple Method of Evaluating the Thermal Properties of Metallurgical Cokes under High Temperature

The reactivity index of weight loss (RI) and tumbling strength after the reaction (I₁₀⁶⁰⁰) of manufacturing coke were first tested at a temperature series of 1100, 1200, and 1300 °C under CO₂ atmosphere with different compositions and duration times to study the effects of temperature, time, and gas composition on coke hot strength. Then the RI/I₁₀⁶⁰⁰, carbon structure, and optical texture of the cokes prepared from different single coals were mainly studied after a solution reaction with CO₂ under a high temperature of 1300 °C and a standard temperature of 1100 °C. It was found that temperature greatly affects the RI/I₁₀⁶⁰⁰ of coke, especially at high temperatures up to 1300 °C. Compared with standard tests under 1100 °C, the changes of RI/I₁₀⁶⁰⁰ for different cokes are very different at 1300 °C, and the changes are greatly related to coke optical texture. Under a high temperature in the testing method, the tumbling strength of cokes with more isotropy increased, whereas it decreased for those with less isotropy. This simple method of using high temperature could yield the same results when compared with complicated simulated blast furnace conditions.

Bimetallic Ni-Ru and Ni-Re Catalysts for Dry Reforming of Methane: Understanding the Synergies of the Selected Promoters

Designing an economically viable catalyst that maintains high catalytic activity and stability is the key to unlock dry reforming of methane (DRM) as a primary strategy for biogas valorization. Ni/Al₂O₃ catalysts have been widely used for this purpose; however, several modifications have been reported in the last years in order to prevent coke deposition and deactivation of the samples. Modification of the acidity of the support and the addition of noble metal promoters are between the most reported strategies. Nevertheless, in the task of designing an active and stable catalyst for DRM, the selection of an appropriate noble metal promoter is turning more challenging owing to the lack of homogeneity of the different studies. Therefore, this research aims to compare Ru (0.50 and 2.0%) and Re (0.50 and 2.0%) as noble metal promoters for a Ni/MgAl₂O₄ catalyst under the same synthesis and reaction conditions. Catalysts were characterized by XRF, BET, XRD, TPR, hydrogen chemisorption (H₂-TPD), and dry reforming reaction tests. Results show that both promoters increase Ni reducibility and dispersion. However, Ru seems a better promoter for DRM since 0.50% of Ru increases the catalytic activity in 10% and leads to less coke deposition.

Evaluation of a Ti-Base Alloy as Steam Cracking Reactor Material

Low-coking reactor material technologies are key for improving the performance and sustainability of steam crackers. In an attempt to appraise the coking performance of an alternative Ti-base alloy during ethane steam cracking, an experimental study was performed in a jet stirred reactor under industrially relevant conditions using thermogravimetry (T_gasphase = 1173 K, P_tot = 0.1 MPa, X_C2H6 = 70%, and dilution δ = 0.33 kg_H2O/kg_HC). Initially, a typical pretreatment used for Fe-Ni-Cr alloys was utilized and compared with a pretreatment at increased temperature, aiming at better surface oxidation and thus suppressing coke formation. The results revealed a decrease in coking rates upon high temperature pretreatment of the Ti-base alloy, however, its coking performance was significantly worse compared to the typically used Fe-Ni-Cr alloys, and carbon oxides formation increased by a factor of 30 or more. Moreover, the analyzed coupons showed crack propagation after coking/decoking and cooling down to ambient temperature. Scanning electron microscopy combined with energy-dispersive X-ray spectroscopy indicated that the prompt and unsystematic oxidation of the surface and bulk caused observable crack initiation and propagation due to alloy brittleness. Hence, the tested Ti-base alloy cannot be considered an industrially noteworthy steam cracking reactor alloy.

Chronic Consumption of a Commercial Energy Drink Reduces Blood Pressure in Normotensive Wild-Type Mice

Objective: Studies report that acute consumption of energy drinks transiently increases blood pressure (BP). However, few studies report the effect of chronic energy drink consumption on BP. In this study, we investigated the effects of long-term energy drink ingestion on BP in C57BL/6J normotensive wild-type mice.

Research Methods and Procedures: Groups of mice were randomized to no treatment (water) (Control group), or to Mother^™ provided as a decarbonated 30% (v/v) drinking solution (Energy Drink group), sugar-free Mother^™ at 30% (Sugar-free group), Coca Cola^™ at 30% (Coke group) for a total intervention period of 13 weeks.

Results: After 13 weeks of intervention, the control mice showed a modest increase in systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) by 7.1 ± 8.8, 5.8 ± 9.4, and 6.3 ± 9.1 mmHg, respectively. However, the Energy Drink significantly decreased the DBP and MAP by 18.8 ± 9.9 and 15.3 ± 9.8 mmHg, respectively. Similarly, Sugar-free group mice showed significant decrease of the SBP, DBP, and MAP by 10.85 ± 5.6, 18.7 ± 6.7, and 15.6 ± 6.1 mmHg, respectively. The SBP, DBP, and MAP in Coke mice showed no significant changes. The estimated cumulative intake of caffeine, taurine, and vitamin B3 and B5 was significantly higher in the mice of Energy Drink and Sugar-free groups compared to the Control and Coke mice.

Conclusion: Collectively, the data suggest that the long-term chronic consumption of energy drinks may significantly lower the BP in normotensive mice through the actions of caffeine, taurine, and/or B-vitamins. The study findings do not support consideration of energy drinks for BP management, but rather demonstrate no long-term amplification of BP in normotensive preclinical models.

Curing of Epoxy Resin DER-331 by Hexakis(4-acetamidophenoxy)cyclotriphosphazene and Properties of the Prepared Composition

The method of optical wedge revealed that the optimum temperature for compatibility of hexakis(4-acetamidophenoxy)cyclotriphosphazene (ACP) and DER-331 epoxy resin is in the range of 220-260 °C. The interdiffusion time of components at these temperatures is about 30 min. The TGA and differential scanning calorimetry (DSC) methods revealed the curing temperature of 280 °С for this composition. IR spectroscopy confirmed that the reaction between the resin and ACP is completed within 10 min. According to the DSC data, a glass transition temperature of 130 °С was estimated for the cured resin. Combustion test UL-94 demonstrated that the obtained material can be assigned to the fireproof category of V-0. Burning droplets were not formed during the burning. The coke formed during the combustion of samples possessed a dense and porous structure. The shape of pores is closed, while their size is in the range of 0.2-200 µm.

Steam Reforming of Model Bio-Oil Aqueous Fraction Using Ni-(Cu, Co, Cr)/SBA-15 Catalysts

Hydrogen obtained from biomass derivatives is considered a promising alternative to fossil fuels. The aim of this work is to test the viability of Ni-M/SBA-15 (M: Co, Cu, Cr) catalysts for the hydrogen production from bio-oil aqueous fraction reforming. Tests were performed in a fixed-bed reactor at 600 °C and atmospheric pressure. Firstly, the steam reforming (SR) of acetic acid, hydroxyacetone, furfural and phenol, as representative constituents of the bio-oil aqueous fraction, was carried out. Lower reactivity with increasing carbon number and decreasing steam-to-carbon ratio was observed. Coking rate during SR is a consequence of carbon number and aromaticity of the reactant, as well as the steam-to-carbon ratio. However, deactivation also depends on the graphitization degree of carbon filaments, higher in the case of coke formed from phenol. Then, the performance of the Ni-M/SBA-15 catalysts was studied in the reforming of a bio-oil aqueous fraction surrogate containing the four model compounds. Ni-Co/SBA-15 and Ni-Cr/SBA-15 samples were the most active because Co also catalyze the steam reforming reactions and Cr promotes the formation of very small Ni crystallites accounting for high conversion and the low coke deposition (~8 times lower than Ni/SBA-15) in the form of poorly condensed carbon filaments.

Photocatalytic activities of coke carbon/g-C3N4 and Bi metal/Bi mixed oxides/g-C3N4 nanohybrids for the degradation of pollutants in wastewater

Different g-C₃N₄ composite systems (coke carbon/g-C₃N₄, Bi/Bi₂WO₆/g-C₃N₄ and Bi/Bi₂MoO₆/g-C₃N₄) have been assessed as photocatalysts for wastewater pollutants removal. The coke carbon/g-C₃N₄ hybrid, produced by thermal treatment at 550 °C of a composite made from melamine cyanurate and coke, only showed activity under UV-light irradiation. On the other hand, inorganic Bi spheres/Bi mixed oxides/g-C₃N₄ nanohybrids (Bi/Bi₂WO₆/g-C₃N₄ and Bi/Bi₂MoO₆/g-C₃N₄ composites), produced by thermal reduction of Bi₂WO₆ or Bi₂MoO₆ by g-C₃N₄, exhibited a remarkable red-shift, up to 620 nm, and allowed the visible-light driven degradation of the contaminant, albeit in combination with some adsorption.

Effects of atamp-charging coke making on strength and high temperature thermal properties of coke

The stamp-charging coke making process has some advantages of improving the operation environment, decreasing fugitive emission, higher gas collection efficiency as well as less environmental pollution. This article describes the different structure strength and high temperature thermal properties of 4 different types of coke manufactured using a conventional coking process and the stamp-charging coke making process. The 4 kinds of cokes were prepared from the mixture of five feed coals blended by the petrography blending method. The results showed that the structure strength indices of coke prepared using the stamp-charging coke method increase sharply. In contrast with conventional coking process, the stamp-charging process improved the coke strength after reaction but had little impact on the coke reactivity index.