Coal Liquefaction Research Articles

Green Energy Transition: Evaluating Carbon-To-Liquid Technologies for 2050 Climate Goals and Energy Security

China's coal-to-liquid (CTL) sectors must quickly adjust to a low-carbon economy to meet the energy demand while mitigating environmental and energy security challenges. Similarly, China's climate goals for 2050 are gravely jeopardized if the industry's enormous ecological impact is not addressed. This research develops a conceptual framework for environment-security-economic evaluation of the high-carbon energy sector. Moreover, it constructs a system dynamics material model to predict the upgrade plan's industrial capacity and carbon emission scale. Finally, it calculates the dynamic optimal deployment scale at various epochs based on the sequential decomposition goal of "carbon peak" and "carbon neutrality." These measures are needed to anticipate the development of China's CTL industry. The road map predicts that by 2025, China's CTL industry will be able to meet at least 5% of the country's total oil demand. The adoption of scale A process will improve the economic and environmental performance of the CTL industry due to the cost savings and efficiency gains at a larger scale. In addition, the industry's overall energy efficiency will rise in 2023 and exceed 50% after 2035. Findings indicate that the CTL sector will approach a carbon peak in 2029 and neutrality and transition to hydrogen generation by 2050.

Influence of direct coal liquefaction residue (DCLR) on the rutting behavior of asphalt mixture with the discrete element method

The research explores the influence of direct coal liquefaction residue (DCLR) as a fine aggregate on the rutting behavior of asphalt mixtures (AMs). Four AMs were prepared and modeled, namely AM (AM-0), AM with 2.36 mm DCLR (AM-2.36), AM with 1.18 mm DCLR (AM-1.18), and AM with 0.6 mm DCLR (AM-0.6). Firstly, the rutting depth and uplift height of AMs were analyzed. Results indicated that the rutting depth and uplift height of AMs increased with rising temperatures and loads. The order of rutting depth and uplift height of AMs at different temperatures and loads was: AM-0＞AM-2.36＞AM-1.18＞AM-0.6. This suggests that DCLR replacing fine aggregates improved the high-temperature performance of AMs, and DCLR replacing 0.6 mm fine aggregate was the best alternative. Moreover, the influence mechanism of DCLR on the rutting behavior was investigated by the force chain distribution and particle movement. The results showed that the rutting deformation was caused by the movement of 0.6–2.36 mm particles. Compared with AM-0, the chain distribution of AM-2.36 was uniform and sparse, and the movement of 0.6–2.36 mm particles in AM-2.36 was small. This was due to the composite modification effect of DCLR within the AM, which increased the bonding degree of asphalt mastics. This enhancement improved connectivity between aggregates, strengthened their load transfer capacity, and raised the AM's overall self-organizing adaptability. Finally, it was also found that DCLR as fine aggregates served dual roles within the AM, acting both as a skeleton and a filler.

Direct liquefaction behavior of Shenhua Shangwan coal under CO containing atmosphere

Direct coal liquefaction (DCL) under CO or syngas atmosphere is beneficial to reduce the cost of hydrogen production. Effects of CO on liquefaction process of Shangwan coal were investigated by comparing the liquefaction behavior in three atmospheres of CO, H2, and N2. Then, effects of different CO/H2 ratios and catalysts on the liquefaction process in syngas were investigated. The results indicated that the oil yield under CO atmosphere reached 43.1%, which was 4.2% lower than that under H2, but 10.2% higher than that under N2. The liquefaction performance was further improved by adding the Shenhua 863 catalyst. It is analyzed that CO promoted liquefaction in two ways: water-gas shift reaction and the reaction between CO and organic structures of coal. Through characterization of the products by GC-MS and FT-IR, it was found that CO makes benzenes, aliphatics, and oxygen-containing compounds in liquefied oil simultaneously increased. The effect on functional groups and free radicals concentration in the solid products was not obvious. The experimental results under syngas showed that the highest oil yield, 57.4%, can be obtained in DCL with 20% CO syngas, and further improved by increasing moisture content of coal appropriately. In addition, the Shenhua 863 catalyst had a good catalytic effect on the liquefaction process and also water-gas shift reaction.

Experimental characterization on injection and spray of coal-derived liquid fuel

Coal-derived liquid fuels (CDLs) are petroleum diesel's (PD) alternatives produced by coal liquefaction. The injection and non-evaporating spray characteristics of CDLs, including diesel from direct coal liquefaction (DDCL), diesel from indirect coal liquefaction (DICL), and their blends (DBCL), were discussed. The high-pressure common rail test bench was used to evaluate the injection delay, injection rate, injection quantity, single injection heat value, and injector inlet pressure. A constant volume chamber along with high-speed camera was used to visualize the spray, then measuring the spray tip penetration distance, spray cone angle, and spray area. Besides, injection tests were conducted using injectors removed from engines that had finished durability tests fueled with DBCL and PD. The results revealed that DDCL had shorter injection delays and more mass injection quantity than PD, with an injection heat value 7 % higher at a rail pressure of 140 MPa. Regarding the spray, PD had a longer spray tip penetration distance and smaller cone angle than CDLs. On test conditions, the spray Sauter mean diameters of DDCL and DICL were over 30 % less than that of PD. Inferring from the reduction in injection rate and quantity, PD generated more clog in the injector hole than DBCL.

Turning coal hydrogenation liquefaction residue into high conductivity carbon black with magnesium citrate-assisted steam activation followed by high temperature treatment

The high conductivity carbon black was prepared using coal hydrogenation liquefaction residue as raw material, through a combination methods of solvent extraction purification, magnesium citrate-assisted carbonization, steam activation, and high-temperature treatment. The effects of carbonization and activation process parameters, heat treatment temperatures, and other factors on the microstructure, specific surface area, degree of graphitization, and conductivity of the carbon black were studied. The coal direct liquefaction residue was firstly purified using a xylene and tetrahydrofuran solution with a volume ratio of 1:1 by centrifugal separation method to obtain coal liquefaction asphalt. Then, the coal liquefaction asphalt was mixed with magnesium citrate in a mass ratio of 3:7 and ball-milled for 90 min. After carbonizing at 950 °C for 120 min, magnesium ions were leached out with hydrochloric acid. The obtained sample was activated with steam at 900 °C for 100 min and then underwent high-temperature treatment at 1500 °C under a N2 atmosphere for 120 min. The microstructure of the conductive carbon black exhibited an irregular blocky structure with an average particle size of 2–10 μm. The specific surface area of carbon material was 579.69 m2/g, with the pore distribution predominantly microporous, accounting for 69.81 % of the total pore volume. It featured a higher degree of graphitization (ID/IG=1.06) and fewer surface oxygen-containing functional groups compared with coal direct liquefaction residue. Electrochemical testing showed that the electrical resistance of the carbon material was only 1.55 Ω, and the reversible capacity under a current density of 1 A/g was 96 mAh/g, which are superior to those of the existing commercial conductive carbon black. The microporous structure and higher degree of graphitization facilitate efficient electron transmission, while the lower content of surface oxygen functional groups effectively reduces electron transfer resistance. This work offers new insights into the structural design and performance enhancement of coal liquefaction residue-derived conductive carbon black functional materials. Furthermore, it has significant implications for the future development of conductive carbon black in energy saving and energy storage.

Sulfur Vacancies are the Active Sites in the Iron Sulfide Catalyst for the Hydrogenation of Naphthalene

AbstractIron sulfide catalysts could boost the hydrogenation of polycyclic aromatic hydrocarbons, and have been widely employed in direct coal liquefaction owing to their low price and good activity. In the past, the Fe deficient structure on Fe1−xS was normally considered as the active site. Herein, the promotion effect of S vacancies on the performance in the naphthalene hydrogenation reaction was revealed. Additional S vacancies on the prepared Fe1−xS catalyst were introduced by a heat‐treatment under H2. Multiple characterization techniques verified that the density of S vacancies on catalyst surface increased with the prolonged H2 treatment time, while the Fe deficient structure displayed an opposite trend. The performance in the hydrogenation of naphthalene to tetralin was used to evaluate the catalyst activity. It was found that the sequence of naphthalene conversion over catalysts was consistent with the corresponding content of S vacancies, indicating that S vacancies were more efficient active sites. DFT calculation results revealed that both molecular H2 and naphthalene exhibited a pronounced inclination towards adsorption on S vacancies as compared to intact surface of Fe1−xS. The increasing amount of S vacancies facilitated the adsorption of reactants and the weakening of naphthalene C−C bonds.

Illuminating the path to decarbonization: Nuclear energy consumption, clean energy production, and sustainable fuel production for long-term development

The global concern over carbon emissions has necessitated a deep understanding of energy use and air pollution. The fossil fuel- and nuclear-dependent Russian economy is an exciting exception. It examined how nuclear energy consumption (NEC), electricity generation, R&D investment, clean energy production technology, e-commerce penetration, capital creation, and carbon pollution affect the Russian economy. Short- and long-term interactions between these variables are assessed using the ARDL-Bound testing model for 1995Q1–2020Q4. The results show that NEC negatively correlates with CO2 emissions. The study also supports the inverted U-shaped Environmental Kuznets Curve (EKC) hypothesis, showing a positive and significant relationship between clean power production technology and CO2 emissions and a negative and significant relationship between square clean alternative energy innovation and CO2 emissions. Scientific and technical expenditures, fossil fuel coal liquefaction, and investment all negatively and statistically significantly affect CO2 emissions. However, the analysis implies that e-commerce increases CO2 emissions. These findings highlight the need for significant R&D investment to create precise and realistic ways to decrease carbon emissions and protect the environment in accordance with COP 26 targets. These findings have significant implications for the Russian economy, showing that improving energy sources and investing more in R&D may reduce carbon emissions.

On the FT-ICR mass spectrometry analysis of dissolved organic matter released by adsorbent during coal chemical wastewater treatment

This study analyzed the dissolved organic matter (DOM) released by adsorbent during wastewater treatment. It was found that the adsorption method resulted in an organic removal efficiency of over 97 % for coal-to-olefin (CTO) wastewater, with the lowest value of 15.7 mg/L. The Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) detected 4111 DOM in the wastewater, 4052 remaining DOM after first-stage anthracite (ANC) adsorption, and 1013 after second-stage macroporous adsorption resin (MAR). The removal degree of lipids in wastewater was the highest, followed by aliphatic/amino-acid/mini-peptides and lignin. During the adsorption process, the proportion of halogenated compounds (HCs) declined from 59.86 % to 38.63 % and 21.67 %. Additionally, freshly produced 2035 and 311 DOMs were found in the adsorption effluent of ANC and MAR, respectively, with HCs accounting for 34.71 % and 67.96 %. Upon flowing ultra-pure water through ANC and MAR, the effluent dissolved organic carbon (DOC) ranges were 1.118–3.574 mg/L and 1.014–2.557 mg/L, respectively. There were 159 and 131 species of DOM detected, respectively, with HCs content of 59.06 % and 45.02 %. Comparative experiments revealed the complex components of the wastewater promoting the release of organic matter on the adsorbent surface that further reacted to generate organic matter. However, fewer substances were released by the adsorbent.

An experimental study of surrogates of diesel from indirect coal liquefaction and the development of an improved kinetic mechanism

The increasing energy shortage and environmental pollution make the use of clean and efficient alternative fuels an effective way to solve the emission problem. Diesel from indirect coal liquefied (DICL) is a clean and efficient alternative fuel for diesel engines. The composition and chemical kinetics mechanism of DICL research contributes to a better understanding of combustion and pollutant formation process. The components of DICL were analysed by gas chromatography-mass spectrometry (GC-MS). The proportion of normal alkanes contained in DICL is particularly high, 93.82%, which proves that its reactivity is particularly good. The mixture of n-dodecane and iso-octane was selected as the surrogates of DICL. The oxidation process of DICL surrogates was examined by a jet-stirred reactor (JSR) over the temperature range of 500–890 K. A detailed kinetic mechanism of surrogates encompassing 1356 species and 6008 reactions was constructed. The critical reactions associated with the reactivity of surrogates were adjusted by the sensitivity analysis method to increase the accuracy of mechanism prediction. The predicted value of the improved mechanism is in good agreement with the experimental value. The improved mechanism can reasonably predict the oxidation process and the ignition characteristics of DICL and the improved mechanism can provide a good reference value for the subsequent analysis of combustion and emission problems of DICL. Abbreviations: C/H, C/H ratio; CN, cetane number; DDCL, direct coal liquefy diesel; DICL, Diesel from indirect coal liquefied; GC-MS, gas chromatography-mass spectrometry; HMN, 2,2,4,4,6,8,8-heptamethylnonane; HXN, n-hexadecane; IDT, ignition delay time; JSR, jet-stirred reactor; LHV, low heating value; LLNL, Lawrence Livermore National Laboratory; NSRL, National Synchrotron Radiation Laboratory; NTC, negative temperature coefficient; PICS, photoionization cross section; PRF, gasoline substitute; PSR, perfectly stirred reactor; SVUV-PIMS, Synchrotron VUV photoionization mass spectrometry; TOF-MS, time-of-flight mass spectrometer

A comparative techno-economic analysis for implementation of carbon dioxide to chemicals processes

CO2-based carbon-neutral organics production processes could potentially reshape the chemical industry. However, their feasibility and net carbon footprint rely strongly on the sources of H2. Herein, we present a comprehensive comparative techno-economic analysis of CO2-based methanol (CO2TM) and α-olefins (CO2TO) manufacturing using various feedstock supply modes: 1) the standalone mode, with external CO2 and H2 from on-site water electrolysis, 2) the integrated mode with CO2 and H2 recovered from coal-chemical plants, and 3) the integrated mode with recycled CO2 but H2 from on-site water electrolysis. The integration of CO2TM and CO2TO into coal-to-olefins (CTO) and coal-to-methanol (CTM) facilities is currently cost-effective and can reduce net CO2 emissions by 65.7% and 68.5%, resulting in a three-fold and two-fold increase in carbon efficiency, respectively. As carbon tax policies and electrolysis technologies continue to evolve, standalone CO2TM and CO2TO are projected to become more economically competitive than CTO and CTM by 2035–2045.

Revealing the Molecular Interaction between CTL Base Oil and Additives and Its Application in the Development of Gasoline Engine Oil

In order to improve fuel economy to meet the standard for passenger car oil, a new formulation with good viscosity–temperature performance for gasoline engine oil is required. In this study, coal-to-liquid (CTL) base oil, with a high viscosity index and good low-temperature performance, was selected as the base oil to develop the gasoline engine oil. A systematic study on the molecular interaction between the CTL base oil and the viscosity index improver (VII), including three kinds of hydrogenated styrene diene copolymers (HSD-type) and four kinds of ethylene propylene copolymers (OCP-type), was conducted. It was found that in general, in CTL base oil, the HSD-type VII exhibited a much higher viscosity index, a significantly lower shear stability index, a higher thickening ability, and a lower cold-cranking simulator (CCS) viscosity than that of OCP-type VII. Moreover, when comparing CTL base oil with mineral oil 150N, the combination of CTL base oil and the VII displayed a lower CCS viscosity than that of mineral oil, suggesting it had better low-temperature performance and was able to quickly form a protective oil film on the surface, which was beneficial for the cold start. The functional group distribution state of the VII in base oil was analyzed using synchrotron radiation micro-infrared microscope (SR Micro-IR) technology, which revealed that HSD-1 had a better molecular interaction with CTL6 than 150N because of the better uniformity of the C=C group distribution. Based on this, a SP 0W-20 gasoline engine oil was developed by the combination of CTL base oil and the HSD-1 viscosity index improver, together with an additive package, a polymethacrylate pour point depressant, and a non-silicone defoamer, which showed excellent low-temperature performance, thermal oxidation stability, and detergency performance compared to the reference oil.

Exploration on the synergistic effect of antioxidants for coal-to-liquid base oil: From the perspective of oxidation resistance and thermal stability

Coal-to-liquid (CTL) base oil is a high-quality lubricant base oil made from coal. However, its poor oxidation stability and short service life limit its application. Pressurized differential scanning calorimetry and Rotary bomb oxidation test are utilized for the evaluation of oxidation stability. Thermogravimetric analysis is performed for the thermal stability assessment. The results showed the reasonable combination of commercial antioxidants can significantly improve the oxidative and thermal stability of two typical CTL base oils, CTL3 and CTL6. The synergistic mechanism of antioxidants in CTL base oil was studied from the perspective of pyrolysis kinetics and pyrolysis mechanism. For CTL3, adding the compound antioxidant 2,6-di-tert-butyl-4-methylphenol (T501) and n-phenyl-1-naphthylamine (T531) results in an almost eightfold increase in oxidation induction time (OIT) and a 33.4 % increase in activation energy compared to pure CTL3. For CTL6, adding the compound antioxidant dialkyl dithiophosphate (T203) and diphenylamine (L57) results in an almost tenfold increase in OIT and a 10.9 % increase in activation energy compared to pure CTL6. The designed commercial antioxidant compound systems had excellent synergistic effects and the synergistic mechanisms were illustrated.

Extractive distillation of cycloalkane monomers from the direct coal liquefaction fraction

Extractive distillation of cycloalkane monomers from the direct coal liquefaction fraction

Utilization of direct coal liquefaction residue (DCLR) in recycled emulsified asphalt mixtures: A solution as geopolymer binder and filler materials

The study evaluates the feasibility of using coal liquefaction residue (DCLR) as a substitute for mineral powder and DCLR-based polymers as a substitute for cement in emulsified asphalt mixtures containing 100 % recycled asphalt pavement (RAP). This research examines the impact of various curing regimes on the functional attributes of the modified emulsified asphalt mixtures by evaluating road performance, compressive strength, and elastic modulus. The findings indicate that DCLR can effectively substitute mineral powder, maintaining the mixture’s stability and durability. The "three-stage double compaction" curing technique significantly enhances mechanical properties. Furthermore, the incorporation of DCLR-based geopolymers augments the dynamic stability of the mixture, albeit slightly affecting bending strain and residual stability. The integration of DCLR-based geopolymers substantially boosts the shear resistance of cold-recycled mixtures. During the enhancement of mixture performance, DCLR primarily serves a physical filling role, whereas DCLR-based geopolymers contribute to performance improvement through physicochemical interactions. This study validates the practicality of employing DCLR in emulsified asphalt mixtures for high-temperature applications, suggesting a sustainable pathway for asphalt mixture design.

The formation of carbon deposits on catalyst during sulfurization of iron-oxides with aromatics as liquid medium

To obtain the proper catalyst activity for direct coal liquefaction, the iron-oxides, as a precursor of iron-based catalysts, were sulfurized in the liquid medium before use. The hydrogen-donating solvent, a promising liquid medium, benefited the process design. However, it was found to be not conducive to the catalyst activity. Herein, the influence on catalysts from aromatics was investigated. Synthetic iron-oxides were sulfurized under H2S flow in the mixtures of decalin and selected aromatics including xylene, naphthalene, phenanthrene and pyrene. The catalyst activity was evaluated based on its performance in the catalytic hydrogenation of naphthalene. It was found that pyrene had a significant negative effect on catalyst activity, which was mainly related to the condensation of pyrene on the catalyst. The fact was that the amount and condensation degree of carbon deposits on the tested catalysts were inversely proportional to their activities. The condensation of pyrene was related to both elemental sulfur and iron species. The effect from the two factors separately on pyrene condensation was limited, while the synergetic effect when they worked together made the condensation extent increased significantly. The elemental sulfur reacted with pyrene at elevated temperatures and induced the condensation of pyrene. Besides, density-functional-theory calculation results revealed that the chemical bonds of both elemental sulfur and pyrene were weakened by iron-sulfides.

Carbon tax to phase out coal as propylene feedstock and control upstream methane emissions in China: Based on dynamic radiative forcing

Carbon tax is a policy instrument that facilitate the phase-out of coal as a chemical feedstock and help China achieve an early carbon peak. However, the policy design is challenged by the complex dynamics of global warming potentials (GWP) from upstream methane emissions, which have a short atmospheric lifetime but a high climate impact. In this study, we compared the life-cycle GWP of two propylene production routes in China: Coal-to-Olefin (CTO) and Propane Dehydrogenation (PDH). We also conducted a cost-profit analysis that incorporates the carbon tax, considering uncertainties in the dynamic radiative forcing of methane. We derived a range of optimal carbon tax rates that can enhance the economic competitiveness of low-carbon propylene routes PDH and discourage the expansion of coal-fed CTO propylene routes. Results show that, for the propylene sector in China, the carbon tax rate should be between 86 and 600 Chinese Yuan (CNY) or 12–84 US dollars (USD) per ton of carbon dioxide equivalent (CO2e), which corresponds to 1–10% of the typical propylene price in the Chinese market. Our study provides spatiotemporal insights into the carbon tax for China's propylene sector to decarbonize and control upstream methane emissions. Since propylene is one of the key raw materials for chemical (e.g., plastic) productions, our analysis contributes to the climate benefits of global chemical trade.

Influence of compatibilization methods on the compatibility between asphalt and DCLR components with molecular dynamics (MD) method

This study aims to investigate the effect of compatibilization methods on the compatibility between asphalt and direct coal liquefaction residue (DCLR) components to identify the key components in DCLR and asphalt that affect their compatibility. In this article, three types of compatibilizers, including benzyl alcohol (BA), dioctyl phthalate (DOP), and BA/DOP, were selected and acted on asphalt's components and DCLR's components, respectively. The molecular models of asphalt components, asphalt components with compatibilizers, DCLR components, and DCLR components with compatibilizers were established. The compatibility between DCLR and asphalt's four components, as well as between asphalt and DCLR's three components, were evaluated by solubility parameter difference (SPD) and interaction energy (IE). The compatibility between DCLR and asphalt was analyzed by Segregation test and Scanning Electron Microscope. Results indicate that the SPD and IE values between DCLR and asphalt components declined after adding compatibilizers, which implies that the repulsion decreased and the attraction increased between asphalt components and DCLR and the compatibility between asphalt components and DCLR improved. The IE values between DCLR components and asphalt increased after adding compatibilizers, which indicates that the compatibility was reduced between DCLR components and asphalt. The SPD values between DCLR components and asphalt increased after adding the BA/DOP. The SPD values between pre-asphaltene and asphalt decreased after adding the BA and DOP. The SPD value between asphaltene in DCLR and asphalt increased after adding the BA and decreased after adding the DOP. Moreover, the storage stability and homogeneity of DCLR-modified asphalt improved after adding compatibilizers, indicating that the compatibilizers enhanced compatibility between DCLR and asphalt. Finally, comparing the results of the tests, it could be found that compatibilizers preferentially acted on the asphalt components and mainly affected the aromatics in asphalt, thereby improving the compatibility between asphalt and DCLR. The effect of BA/DOP on improving the compatibility between asphalt and DCLR was better than that of BA and DOP.

Preparation of high-performance bitumen carbon-based microwave absorbing materials from different coal bitumens toward efficient treatment of industrial waste bitumen

The increasing development of communication technology and electromagnetic pollution have accelerated the research and optimization of electromagnetic microwave absorbing materials. There are few studies and reports on the creation electromagnetic microwave absorbing materials from industrial waste, despite the abundance and promise of research preparing of microwave absorbing materials utilizing sustainable resources from biomass. Herein, we prepared carbon-based microwave absorbing materials GCB-800, HTCB-800, and CDLB-800 using three different industrial solid waste bitumens, namely, coal direct liquefaction bitumen, high-temperature coal bitumen, and globular coal bitumen, as raw materials by using the thermal activation method. Due to the excellent porous carbon skeleton structure and the Fe2O3 contained in its internal ash after the heat treatment, which enhances the internal dielectric properties, the CDLB-800 was found to perform very well at the filler amount of 10 wt% obtained minimum reflection loss (RLmin) is −52.41 dB at 10 wt% filler and matched thickness d = 2.1 mm, and the effective absorption bandwidth (EAB) is 4.88GHz, with 87.14% absorption for X-band in the 2-18GHz. This work not only promotes the development of the comprehensive utilization of solid waste in this field, effectively reduces the burden of solid waste on the environment, but also points out the direction for the development of microwave absorbing materials in the future.

Mesophase pitch-based high performance carbon fiber production using coal extracts from mild direct coal liquefaction

Mild direct coal liquefaction (autogenous pressure, no catalyst, no H2 gas) of Springfield coal in fluid catalytic cracking decant oil is shown to effectively produce coal extract precursors to spinnable mesophase pitch. This work demonstrates that the coal extract can be thermally treated to obtain mesophase pitch in a facile one-step process, bypassing the production of an intermediate isotropic pitch. Furthermore, the presence of 25 wt.% coal in the initial slurry can increase the yield to mesophase pitch nearly twofold and yield to carbon fiber by approximately 70%. The coal extract-derived mesophase pitch was melt-spun and heat treated to produce carbon fiber with graphitic texture, high modulus (>400 GPa) and tensile strength up to 943 MPa. Overall, this work demonstrates that coal can be effectively utilized to markedly amplify the mesophase pitch and carbon fiber yield from fluid catalytic cracking decant oil by relatively simple processing, while conserving utility as a precursor to high performance carbon fiber and potentially other high value graphitic products.

Erosion Wear Analysis on Valve Cage of Cage-Typed Sleeve Control Valve for Coal Liquefaction

Abstract Cage-typed sleeve control valve (CSCV) is the key basic equipment in direct coal liquefaction projects. The working condition of CSCV has the characteristics of high-pressure difference, high velocity, and high solid content. There is a general issue of liquid–solid two-phase erosion wear in CSCV, which can easily lead to the failure of the internal structure in the valve cage. Therefore, it is necessary to study erosion wear characteristics of internal structures in the valve cage. Considering the real conditions of erosion wear in the valve cage, a simplified T-shaped flow path is designed, and the precision of both the liquid–solid two-phase flow model and the erosion prediction model is validated. The flow characteristics and erosion wear characteristics in the T-shaped flow path under different working conditions are studied. Based on the simulation results of different structural parameters and boundary conditions, the erosion wear of the T-shaped flow path is predicted and calculated by the response surface method. Subsequently, the prediction formula for the maximum erosion rate is derived. The formula enables the swift determination of optimal structural parameters for the flow path, aiming to mitigate damage to the valve caused by erosion wear. This work can quickly predict the erosion wear rate of the key areas in the valve cage, which can provide a certain reference value for the life prediction and structural optimization of CSCV, and it can also benefit the safety and maintenance of the coal liquefaction system.