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Syngas conversion is a useful technology for converting nonpetroleum carbon resources into chemicals such as olefins. Iron- and cobalt-based catalysts, as two major categories, have been extensively studied in Fischer–Tropsch synthesis to olefins (FTO) reactions. Although both iron and cobalt catalysts have shown distinct merits and shortcomings, they are also complementary in their properties and catalytic performances when combined with each other. Herein, Na-modified CoFe bimetallic catalysts were fabricated using a co-precipitation method. It was found that there was a synergistic effect between Co and Fe that promoted a CO dissociation rate and carburization, and an appropriate Co/Fe ratio was conducive to improvements in their catalytic performances. The desired olefins selectivity reached 66.1 C% at a CO conversion of 37.5% for a Co2Fe1 catalyst, while the methane selectivity was only 4.3 C%. In addition, no obvious deactivation was found after nearly 160 h, indicating their potential industrial application. [ABSTRACT FROM AUTHOR]

Syngas conversion provides an important platform for efficient utilization of various carbon-containing resources such as coal, natural gas, biomass, solid waste and even CO2. Various value-added fuels and chemicals including paraffins, olefins and alcohols can be directly obtained from syngas conversion via the Fischer–Tropsch Synthesis (FTS) route. However, the product selectivity control still remains a grand challenge for FTS due to the limitation of Anderson–Schulz–Flory (ASF) distribution. Our previous works showed that, under moderate reaction conditions, Co2C nanoprisms with exposed (101) and (020) facets can directly convert syngas to olefins with low methane and high olefin selectivity, breaking the limitation of ASF. The application of Co2C-based nanocatalysts unlocks the potential of the Fischer–Tropsch process for producing olefins. In this feature article, we summarized the recent advances in developing highly efficient Co2C-based nanocatalysts and reaction pathways for direct syngas conversion to olefins via the Fischer–Tropsch to olefin (FTO) reaction. We mainly focused on the following aspects: the formation mechanism of Co2C, nanoeffects of Co2C-based FTO catalysts, morphology control of Co2C nanostructures, and the effects of promoters, supports and reactors on the catalytic performance. From the viewpoint of carbon utilization efficiency, we presented the recent efforts in decreasing the CO2 selectivity for FTO reactions. In addition, the attempt to expand the target products to aromatics by coupling Co2C-based FTO catalysts and H-ZSM-5 zeolites was also made. In the end, future prospects for Co2C-based nanocatalysts for selective syngas conversion were proposed. [ABSTRACT FROM AUTHOR]

Selective oxidation of methane to oxygenates with O2 under mild conditions remains a great challenge. Here we report a ZSM‐5 (Z‐5) supported PdCu bimetallic catalyst (PdCu/Z‐5) for methane conversion to oxygenates by reacting with O2 in the presence of H2 at low temperature (120 °C). Benefiting from the co‐existence of PdO nanoparticles and Cu single atoms via tandem catalysis, the PdCu/Z‐5 catalyst exhibited a high oxygenates yield of 1178 mmol g−1Pd h−1 (mmol of oxygenates per gram Pd per hour) and at the same time high oxygenates selectivity of up to 95 %. Control experiments and mechanistic studies revealed that PdO nanoparticles promoted the in situ generation of H2O2 from O2 and H2, while Cu single atoms not only accelerated the activation of H2O2 for the generation of abundant hydroxyl radicals (⋅OH) from H2O2 decomposition, but also enabled the homolytic cleavage of CH4 by ⋅OH to methyl radicals (⋅CH3). Subsequently, the ⋅OH reacted quickly with the ⋅CH3 to form CH3OH with high selectivity. [ABSTRACT FROM AUTHOR]

Selective oxidation of methane to oxygenates with O2 under mild conditions remains a great challenge. Here we report a ZSM‐5 (Z‐5) supported PdCu bimetallic catalyst (PdCu/Z‐5) for methane conversion to oxygenates by reacting with O2 in the presence of H2 at low temperature (120 °C). Benefiting from the co‐existence of PdO nanoparticles and Cu single atoms via tandem catalysis, the PdCu/Z‐5 catalyst exhibited a high oxygenates yield of 1178 mmol g−1Pd h−1 (mmol of oxygenates per gram Pd per hour) and at the same time high oxygenates selectivity of up to 95 %. Control experiments and mechanistic studies revealed that PdO nanoparticles promoted the in situ generation of H2O2 from O2 and H2, while Cu single atoms not only accelerated the activation of H2O2 for the generation of abundant hydroxyl radicals (⋅OH) from H2O2 decomposition, but also enabled the homolytic cleavage of CH4 by ⋅OH to methyl radicals (⋅CH3). Subsequently, the ⋅OH reacted quickly with the ⋅CH3 to form CH3OH with high selectivity. [ABSTRACT FROM AUTHOR]

Selectivity control of nitrobenzene hydrogenation remains a great challenge, and it is desirable to develop a green and highly efficient catalytic route toward value-added metastable intermediate products. Herein, we reported that isolated Ru single atoms coordinated with oxygen atoms in CeO2 (Ru-SAs/CeO2) can achieve chemoselective hydrogenation of nitrobenzene to azoxybenzene with a selectivity of 88.2% in a continuous flow reactor using H2 without using any bases or expensive organic reducing agents, while 82.7% aniline selectivity was obtained by Ru nanoparticles. We demonstrated that the unique coordinated structure between Ru single atoms and O atoms preferentially controls the reaction route toward the coupling of nitrosobenzene and phenylhydroxylamine intermediates to form azoxybenzene while greatly suppressing over-hydrogenation. The present work provides an efficient strategy to regulate the reaction pathway of nitrobenzene hydrogenation with a green and industry-friendly process by designing highly dispersed Ru single atoms. [ABSTRACT FROM AUTHOR]

Cobalt carbide (Co2C) exhibits strong facet effect for Fischer‐Tropsch to olefins (FTO) reaction. Herein, we report that the facet proportion of Co2C nanostructures can be tuned effectively by incorporating and altering the Mn content in the CoMn composite oxide as catalyst precursor. With the addition of Mn promoter, the Co2C nanoprisms with exposed (020) and (101) facets are generated under reaction conditions. In addition, the facet proportion of Co2C(020) facet can be effectively improved by enhancing the Mn/Co ratio. With the increase of facet proportion of Co2C(020)/Co2C(101) ratio, the as‐obtained Co2C nanoprisms exhibit higher intrinsic activity and lower methane selectivity during the syngas conversion process. Kinetic experiments also demonstrate that the apparent activation energy (Ea) for CO conversion is significantly reduced as increasing the facet proportion of Co2C(020). This work provides a simple and feasible way to tune the exposed facet proportion for the rational design of Co2C nanocatalyst for FTO reaction. [ABSTRACT FROM AUTHOR]

Fischer-Tropsch to olefins (FTO) with controllable iron carbide phase and high carbon utilization efficiency for Fe-based nanocatalyst attracts great interest but remains challenge. Herein, we report that the metastable Fe 7 C 3 phase can be effectively tailored by altering shell thickness of hydrophobic SiO 2 over a core-shell nanostructured FeZn@SiO 2 -c nanocatalyst. χ-Fe 5 C 2 was the dominated iron carbide phase for FeZnO x and FeZn@SiO 2 nanocatalysts, while numerous Fe 7 C 3 phases existed for hydrophobic FeZn@SiO 2 -c nanospheres. Compared with FeZnO x , the CO 2 selectivity of FeZn@ 4.1-SiO 2 -c decreased by > 70%, while 1.7-fold higher olefins selectivity was simultaneously obtained during syngas conversion process. The hydrophobic interface greatly suppressed the water-gas-shift reaction by promoting the quick diffusion of water, and the as-formed H 2 -lean and CO-rich local chemical environment benefits the formation of Fe 7 C 3 and olefins products. This work provides a promising strategy to design phase-stable Fe 7 C 3 with improvement of carbon efficiency for Fe-based nanocatalysts. [Display omitted] • Hydrophobic interfaces could regulate iron carbide phases. • Hydrophobic confined environment benefits the design of phase-stable Fe 7 C 3 carbide. • Fe 7 C 3 is a favorable active phase for Fischer-Tropsch to olefins (FTO). • Wettability environment affects WGS reaction activity and FTO performance. • Suppressed CO 2 selectivity, enhanced activity and olefins selectivity was obtained. [ABSTRACT FROM AUTHOR]

Abstract In order to prevent well leakage in high temperature and high pressure (HTHP) wells, pressure test is a very important leak prevention operation that causes artificial high-pressure environment in wellbore. However, failure of wellbore equipment due to harsh condition is a common problem that brings great economic losses. Ram blowout preventer (BOP) is an important component of wellbore integrity, which is subjected to heavy loads from the test gas and the push rod during the pressure test. Therefore, the serious stress concentration of ram BOP induced by heavy loads and complex geometry is a major reason of fracture. Hence, the focus is to find out the fracture mechanism of ram BOP with experimental method and finite elements (FE) model in this paper. A series of damage inspection and strength test of ram BOP is carried out to find out the fracture characteristics. Based on detection information, FE analysis is conducted to analysis stress distribution and fracture reason of ram BOP. The results show that the maximum stress exceeds the yield strength (705 MPa) of the material under the actual working condition. Serious stress concentration at the notch root of the ram BOP can be easily caused by test pressure (from test gas) and contact pressure (from push rod). Both experimental method and FE analysis show the characteristics of ductile fracture obviously. Stress concentration at notch root is very sensitive to the test pressure. The work presented in this paper can provide basis and reference for preventing failure of ram BOP and improve efficiency and production. Highlights • A three-dimensional finite element model of ram BOP is established. • Stress distribution of ram BOP during service is expressed in finite element model. • Stress distribution of ram BOP is investigated under different conditions. • Stress concentration phenomenon is analyzed at different test and contact pressure. [ABSTRACT FROM AUTHOR]

Selective synthesis of higher oxygenates (linear α‐alcohols and α‐aldehydes, C2+ OH) from syngas is highly attractive but remains challenging owing to the low C2+ OH selectivity and low catalytic stability. Herein we introduce a multifunctional catalyst composed of CoMn and CuZnAlZr oxides that dramatically increased the oxygenates selectivity to 58.1 wt %, where more than 92.0 wt % of the produced oxygenates are C2+ OH. Notably, the total selectivity to value‐added chemicals including oxygenates and olefins reached 80.6 wt % at CO conversion of 29.0 % with high stability. The appropriate component proximity can effectively suppress the formation of the undesired C1 products, and the selectively propulsion of reaction network by synergetic effect of different components contributes to the enhanced selectivity to higher oxygenates. This work provides an alternative strategy for the rational design of new catalysts for direct conversion of syngas into higher oxygenates with co‐production of olefins. A stable multifunctional catalyst composed of CoMn oxides and CuZnAlZr oxides was developed for direct conversion of syngas to higher oxygenates and olefins with a total selectivity of 80.6 wt % at a CO conversion of 29.0 %. The interaction manner of the two components plays a crucial role in suppressing C1 products formation and enhancing the selectivity to higher oxygenates. [ABSTRACT FROM AUTHOR]

Selective synthesis of higher oxygenates (linear α‐alcohols and α‐aldehydes, C2+ OH) from syngas is highly attractive but remains challenging owing to the low C2+ OH selectivity and low catalytic stability. Herein we introduce a multifunctional catalyst composed of CoMn and CuZnAlZr oxides that dramatically increased the oxygenates selectivity to 58.1 wt %, where more than 92.0 wt % of the produced oxygenates are C2+ OH. Notably, the total selectivity to value‐added chemicals including oxygenates and olefins reached 80.6 wt % at CO conversion of 29.0 % with high stability. The appropriate component proximity can effectively suppress the formation of the undesired C1 products, and the selectively propulsion of reaction network by synergetic effect of different components contributes to the enhanced selectivity to higher oxygenates. This work provides an alternative strategy for the rational design of new catalysts for direct conversion of syngas into higher oxygenates with co‐production of olefins. [ABSTRACT FROM AUTHOR]

The Fischer-Tropsch to olefins (FTO) process is a promising alternative non-petroleum route to produce value-added olefins. In this study, Co 2 C nanoprisms formed via the CoMn spinel structure were used as the active phase for the FTO reaction and the product distribution was thoroughly investigated. A break from the traditional ASF model was found with much lower methane selectivity than that predicted by the ideal ASF law. In addition, the as-obtained hydrocarbons were mainly concentrated in the range of C 2 to C 12 with the C 2-12 selectivity as high as 91% while the C 13+ selectivity as low as 5%, indicating a much narrower distribution, which was rarely observed in the FT reaction. Moreover, ∼86% of the hydrocarbon products were olefins with very high olefin to paraffin ratios, suggesting a promising route for the selective production of olefins directly from syngas. A modified ASF distribution model was proposed with three different chain growth probabilities to rationalize the non-ASF phenomenon. [ABSTRACT FROM AUTHOR]

Fischer-Tropsch synthesis (FTS) is a structure-sensitive reaction for sustainable production of green fuels and value-added chemicals via syngas derived from coal, biomass, shale gas and natural gas. The nanostructure of a Fischer-Tropsch (FT) catalyst plays a crucial role in its catalytic performance. This review summarizes recent advances in the investigation of nanoeffects of FT catalysts, especially the effects of the active phase, particle size and exposed facet on catalytic performance. Perspectives and challenges for further research in nanocatalysis for syngas conversion are also given. [ABSTRACT FROM AUTHOR]

Drillstring vibration is one of the primary causes of drillstring failure, well trajectory deterioration, excessive bit wear and low rate of penetration. In order to obtain an improved understanding of drillstring vibration when drilling horizontal wells, an experimental drillstring system is established in this paper on the basis of drillstring dynamics equations and similarity principle. The system is capable of simulating the nonlinear dynamic behaviors of horizontal drillstring. Axial, lateral and torsional vibration phenomena are investigated in steady state. Experimental results indicate that axial force fluctuates wildly when drillstring is buckled. The fluctuation of WOB (weight on bit) is a typical sine curve and the frequency of WOB increases linearly with rotary speed. The lateral vibration is much more severe than axial vibration for horizontal drillstring. According to similarity principle, in order to reduce lateral vibration, the proposed rotary speed range is 37.5 rpm–50 rpm for the actual horizontal drilling operation. The whirling speed amplitude and frequency of horizontal drillstring increase with rising rotary speed. Stick-slip can also occur in horizontal drilling where the rotary speed of bit involves periodic fluctuation varying almost from zero to about twice the surface rotary speed. The work presented in this paper can provide a technological basis for drillstring dynamics and vibration analysis of horizontal wells. [ABSTRACT FROM AUTHOR]

CoMn model catalysts were prepared by co-precipitation and evaluated for higher alcohol synthesis (HAS) via syngas. The selectivity to oxygenates (mainly alcohols and aldehydes) was found to be higher than 20 C% for the Na-promoted CoMn catalyst. Among the oxygenates, C 2+ and C 6+ fractions accounted for >90 wt% and ∼50 wt%, respectively. Metallic Co 0 particles and MnCO 3 were found in both Na-promoted and unpromoted CoMn catalysts after the reaction, whereas Co 2 C nanoparticles could only be observed in the spent Na-promoted catalyst. The addition of Na benefited the carbonization of cobalt and increased the selectivity to oxygenates and CO 2 . Our studies thus suggested that Co/Co 2 C were the bifunctional dual-sites for the oxygenates formation over the Na-promoted CoMn catalyst, where Co catalyzed CO dissociation and chain propagation, while Co 2 C was responsible for CO non-dissociative activation and subsequent insertion. In addition, the sole Co 2 C nanoparticles with certain exposed facets may also act as another kind of active dual-sites for oxygenates formation. [ABSTRACT FROM AUTHOR]

Controlling product selectivity still remains as a grand challenge for syngas conversion to fuels and chemicals. Herein, ZnO modified CoMn-based catalysts were prepared for direct higher oxygenates synthesis via syngas conversion, and the role of Zn promoter on catalytic behaviour and structure evolution was investigated comprehensively. It was found that the addition of Zn greatly reduced the particle size of active phases including Co and Co 2 C. Specially, the Zn promoter facilitated the formation of Co 2 C species, thus effectively tuning the surface ratio of Co/Co 2 C and strengthening the function for CO associative adsorption and insertion for oxygenates product formation. As a result, the oxygenates selectivity was enhanced to 39.1 wt% over ZnO-promoted CoMn-based catalyst, where more than 96.0 wt% of the produced oxygenates are C 2+ products. In addition, Zn promoter can weaken the chain growth ability, leading to the increase of low carbon chain products. [Display omitted] • The addition of Zn promoter greatly reduced the particle size of Co and Co 2 C. • Zn promoter facilitated the formation of Co 2 C. • CO associative adsorption was strengthened for oxygenates formation with Zn addition. • The selectivity of oxygenates was enhanced to 39.1 wt% for Zn-promoted CoMn-based catalyst. [ABSTRACT FROM AUTHOR]

We propose a method for calculating the cuttings (solids) concentration in the annular space and the equivalent circulating density (ECD) in deepwater drilling, both in the pilot hole drilling step and in the reaming step. We have found that drilling a pilot hole followed by reaming has certain advantages over drilling with no pilot hole. When using technology involving preliminary drilling of a pilot hole, the solids concentration in the annular space and the equivalent circulating density are reduced. [ABSTRACT FROM AUTHOR]

With its advantages of lost circulation prevention, drilling speed improvement and reservoir protection, gas drilling technology has been widely applied in Sichuan and Xinjiang oilfields in China . However, drill collar failures have often occurred under high weight on bit (WOB) during gas drilling. These incidents have not only caused serious economic loss but hampered the development and application of gas drilling. Finite element analysis is used to determine the drill collar thread stress distribution and, using simulation of drill string dynamics, multi-axial fatigue life theory is used to calculate the life of a standard API drill collar connection. The computed results reveal the early drill collar fatigue failures in gas drilling. Then, the multi-axial fatigue life of drill collar with double shoulder thread is analyzed under the same loads. Analysis shows that the fatigue life of a double shoulder thread is some thirty times that of the API thread. So drill collar with double shoulder thread could be an efficient way to solve the fatigue failure problems of drill collar in gas drilling. The work presented in this paper can provide theoretical foundations for safe and efficient drilling with gas. [ABSTRACT FROM AUTHOR]

Herein, a series of KGdF4:Yb3+/Er3+ upconversion nanoparticles (UCNPs) were synthesized through a one-pot hydrothermal method using polyethylene glycol (PEG) as capping ligands. The phase and microstructure studies show all these as-prepared UCNPs are pure cubic phase and uniformed nanoparticle shape by changing the doped Yb3+ concentration from 18% to 98%. The as-prepared UCNPs can realize the multicolor emissions from yellow to red and the red-to-green (R/G) ratio can be enhanced from 2.05 to 8.35 when Yb3+ varies from 18% to 98%. In addition, the proposed upconversion (UC) mechanisms of these PEGylated UCNPs are investigated in detail. The realization of multicolor tuning and enhanced R/G ratio by only increasing the doping concentration of Yb3+ ions in KGdF4 host indicates that the PEGylated KGdF4:Yb3+/Er3+ UCNPs can find their application on lighting devices, anticounterfeit technology, and even bioimaging field. [ABSTRACT FROM AUTHOR]

Co 2 C nanoprisms exhibit promising catalytic performance for Fischer-Tropsch synthesis to olefins (FTO) but with high CO 2 selectivity (>40%). Herein, silica-coated CoMn-based catalyst was designed to limit CO 2 production and remained Co 2 C nanoprisms as active sites unchanged. With a desired coating amount of silica, CO 2 selectivity was significantly suppressed to 15.1 C% while enhancing olefins selectivity from 39.7 C% to 58.8 C%, which also shows at least 160 h of stability. It is suggested the silica-coating not only reduces the adsorption capacity of H 2 O, but also promotes the fast transfer of H 2 O away from active sites due to the higher adsorption energy of H 2 O on SiO 2 surface, thus suppressing water-gas-shift-reaction (WGSR) activity. Moreover, the sodium promoter can counteract the H 2 -enrichment effect caused by SiO 2 -coating and largely restrain CH 4 formation and olefins hydrogenation. This work provides an effective strategy to suppress CO 2 formation and enhance the carbon efficiency of FTO process. [Display omitted] • WGSR-resistant CoMnAl@SiO 2 catalyst was prepared for FTO with low CO 2 selectivity. • H 2 O can easily transfer from Co 2 C surface to adjacent hydrophilic SiO 2 sites. • SiO 2 -coating prevents the reabsorption of water on Co 2 C site for further WGSR. • Alkali metals counteract H 2 -enrichment effect of SiO 2 and largely improve O/P ratio. • Low CO 2 emission improved activity, olefins selectivity and carbon-efficiency of FTO. [ABSTRACT FROM AUTHOR]

• The catalytic performance for HAS was dramatically improved by doping Rh or Ru. • The C-rich and H-lean chemical environment was effectively tuned. • The Rhδ+ (or Ruδ+) species benefited the formation and stable existence of Co 2 C. • Synergistic effect of Co 2 C, Co0 and Rhδ+ (or Ruδ+) boosted CO insertion. • Olefins relay coupling promoted the production of oxygenates. Higher alcohols synthesis (HAS) from syngas with high selectivity attracts great attention but remains challenging. Herein, we reported an effective strategy by tuning chemical environment and synergistic relay reaction to promote the production of higher alcohols. CO insertion rate was greatly enhanced by introducing Rh or Ru component to CoMn oxides. The catalytic activity and oxygenates selectivity increased dramatically over the as-obtained Rh-CoMn or Ru-CoMn catalyst, while the fraction of C 2+ OH in oxygenates maintained >92 %. Multiple studies demonstrated the highly dispersed Rhδ+ or Ruδ+ species not only effectively tuned the chemical environment and facilitated the stable existence of Co 2 C, but also catalyzed the coupling of syngas and in-situ generated olefins to produce extra oxygenates via hydroformylation route. The synergistic effect of Co0, Co 2 C and Rhδ+ (or Ruδ+) species, as well as the promotional effect of olefins relay reaction contributed to the enhancement in both higher alcohols selectivity and CO conversion. [ABSTRACT FROM AUTHOR]

Rich contact boundaries of dual active sites can be obtained with enhanced synergistic effect for higher alcohols synthesis when the Co0/Co 2 C ratio was in the appropriate range. • The ratio of Co0/Co 2 C dual active sites was regulated by changing the content of Na. • The effect of Co0/Co 2 C ratio on the catalytic performance was studied for higher alcohols synthesis. • The oxygenates selectivity exhibited a volcano trend with the Co0/Co 2 C ratio. • Rich contact boundaries of dual active sites can be obtained for the suitable Co0/Co 2 C ratio. • Rich contact boundaries of Co0/Co 2 C enhanced the synergistic effect for higher alcohols synthesis. Dual active sites play a vital role in higher alcohols synthesis (HAS) from syngas and the relative proportion of each active sites may greatly affect the contact boundaries between the dual active sites and the reaction network. Herein, we regulated the ratio of Co0/Co 2 C dual active sites by changing the content of Na promoter, and investigated the structure-performance relationship of Co0/Co 2 C for HAS. It was found that both of the catalytic activity and paraffins selectivity increased with the increase of Co0/Co 2 C ratio, while the formation of olefins was inhibited. However, the oxygenates selectivity exhibited a volcano variation trend. The results suggested that only when the Co0/Co 2 C ratio was in the appropriate range, the strong synergistic effect of Co0/Co 2 C dual-site could be obtained, and the CO insertion rate can thus match well with hydrogenation rate and chain-growth rate, which benefited for the oxygenates formation. [ABSTRACT FROM AUTHOR]

The effects of preparation methods of CoMn-based catalysts on the precursor phase of Co species, the morphology of Co 2 C nanostructures as well as the catalytic performance for Fischer-Tropsch to olefins were investigated. • The effects of preparation methods on CoMn catalysts were investigated. • Preparation methods influenced the precursor phase of Co species. • The interaction extent of Co and Mn influenced the reduction process. • Co x Mn 1-x O structure benefited for the formation of Co 2 C nanoprisms. • Co 2 C nanoprisms exhibited better FTO performance than nanospheres. The effects of preparation methods for CoMn-based catalysts on the precursor phase of Co species, the morphology of Co 2 C nanostructures as well as the catalytic performance for Fischer-Tropsch to olefins were investigated. Five catalysts prepared by precipitation and impregnation methods were compared in detail. CoMn spinel oxide was found in the calcined catalysts prepared by co-precipitation or sequential precipitation starting from the Co salt. However, Co 3 O 4 and MnO 2 were the major phases for the calcined catalysts prepared by sequential precipitation starting from the Mn salt or impregnation methods. During the syngas conversion process, Co 2 C nanoprisms with exposed facets of (101) and (020) were generated from CoMn spinel phase, and exhibited high CO conversion, low methane selectivity and high olefins selectivity. In contrast, Co 2 C nanospheres carburized from metallic Co or CoO were observed for the other samples with poorer FTO catalytic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new RuK/Al 2 O 3 heterogeneous hydroformylation catalyst was developed. • RuK possesses higher activity and propanal selectivity than Ru, Rh and Co. • The structure-performance of the RuK and Ru catalysts was investigated. • The synergistic effect of Ru and K facilitates the formation of aldehydes. • K promoted Ru catalysts reduced the hydrogenation of olefins. Hydroformylation is a prototypical C-C coupling reaction of olefins and syngas to produce valuable higher aldehydes. In this study, we investigated the promotional effect of potassium (K) on Ru-based heterogeneous ethylene hydroformylation. The propanal selectivity could reach up to 84.9% at an ethylene (C 2 H 4) conversion of 10.7 % with the addition of K as a promoter. Furthermore, the formation of ethane and the second hydrogenation of olefins were effectively suppressed. Structural characterization results suggested that K promoter could enhance the dispersion of Ru species and increase the electronic density of Ru active sites, thus improving CO adsorption and dissociation. The synergistic effect of Ru and K created a C*-rich and H*-lean local chemical environment, facilitating the formation of aldehydes while effectively reducing the hydrogenation of olefins. This work may provide new insights for development promising Ru-based heterogeneous catalysts for hydroformylation. [ABSTRACT FROM AUTHOR]

A Ru single-atom (Ru SA) catalyst supported on activated carbon was adopted to synthesize 3-pentanone with 83.3% selectivity via heterogeneous ethylene hydroformylation, while 52.1% ethane selectivity was obtained for Ru nanoparticles (Ru NPs). The atomically dispersed Ru species with oxidation state (Ruδ+) and Ru-C4O coordination structure were identified as the active sites for efficient C–C coupling to generate 3-pentanone, while metallic Ru nanoparticles exhibited high activity for ethylene hydrogenation to ethane. Density functional theory (DFT) calculation revealed that the energy barrier of the direct coupling of C2H5CO* with C2H5* to form 3-pentanone on Ru SA was much lower than that on Ru NPs. As a result, the formation of 3-pentanone over Ru SA was more favourable than propanal, which was admittedly generated via coupling of C2H5CO* and H*. This strategy may provide a potential green route for the one-pot synthesis of 3-pentanone with high atomic economy. [ABSTRACT FROM AUTHOR]

As a primary constituent of natural gas and shale gas, direct conversion of methane has attracted significant attention due to its potential to reduce energy consumption and CO2 emissions. Compared with thermal catalysis, photocatalysis has the capacity to transcend thermodynamic constraint and enable the conversion of sustainable solar energy into chemical energy under mild reaction condition, which contributes to optimize the utilization of methane. In this review, we undertake a comparative analysis of various strategies for photocatalytic methane conversion to syngas and chemicals, including photocatalytic reforming of methane, photocatalytic partial oxidation of methane and photocatalytic coupling of methane. The distinct reaction systems with corresponding catalysts and underlying mechanisms are expounded in detail to foster a profound comprehension of solar‐driven methane conversion. Finally, the challenges and prospectives in photocatalytic methane conversion are discussed. [ABSTRACT FROM AUTHOR]

Strong metal‐support interactions (SMSI) featuring the formation of encapsulation overlayer around metal nanoparticles has drawn much attention in heterogeneous catalysis. Recent years, various novel SMSI phenomena have been observed and the nature of SMSI also has been revealed with the improvement of characterization techniques. Understanding the SMSI effect could deepen the insight into the structure‐activity relationship of metal‐supported catalysts, and rationally guide the design of special metal‐interface sites to manipulate catalytic behavior in chemical reaction. In this review, the research progress of SMSI and its application in heterogeneous COx hydrogenation are briefly surveyed, with emphasis on the advanced characterization, manipulation strategy and specific role of SMSI in Fischer‐Tropsch synthesis process, CO2 methanation and Reverse Water Gas Shift reaction. The current challenges and perspectives for the development of SMSI are also discussed. [ABSTRACT FROM AUTHOR]

Photocatalytic methane oxidation to oxygenates with promising performance remains as a grand challenge due to the low productivity and severe overoxidation. Herein, SrWO4/TiO2 heterojunction was developed for photocatalytic methane oxidation with O2 to liquid oxygenates (Please replace "oxygenates" with "oxygenated")products under mild reaction conditions. The optimized SrWO4/TiO2 catalyst exhibited high productivity of 13365 μmol/g with high selectivity of 98.7 % for oxygenates. Benefited from the intimate heterojunction interface of SrWO4/TiO2, the constructed I‐type heterostructure improved the separation and transfer of photogenerated carriers, and a high‐speed transfer channel for photogenerated carriers was fabricated. Simultaneously, the special band structure can increase the amount of photogenerated electrons and holes on the TiO2 surface, which promoted the formation of reactive oxygen species to enhance liquid oxygenates productivity. [ABSTRACT FROM AUTHOR]

Selective oxidation of methane to oxygenates using low‐cost and environment‐friendly molecular oxygen (O2) under mild reaction conditions is a promising strategy but still remains grand challenge. It is of great importance to accelerate the activation of O2 to generate highly active oxygen species, such as hydroxyl peroxide and hydroxyl species to improve catalytic performance for selective oxidation of methane. Selective oxidation of methane using O2 by coupling with in situ generation of hydrogen peroxide via tandem catalysis ensures the easy formation of active oxygen species for methane activation, leading to high oxygenates productivity under mild conditions. In this concept, we summarized the recent progresses for selective oxidation of methane to oxygenates using O2 based on tandem catalysis by coupling with in situ generation of hydrogen peroxide. The remaining challenges and future perspectives for selective oxidation of methane to oxygenates via tandem catalysis were also proposed. [ABSTRACT FROM AUTHOR]

Choke valve is a type of control valve, mostly used in oil and gas production wells to regulate the flow of well fluid and control fluid pressure. Flow characteristics of choke valve are of great significance for valve structure improvement and well production parameters optimization. In order to obtain an improved understanding of flow field and pressure drop in choke valve as well as the whole manifold, a three-dimensional computational fluid dynamics model was established based on the actual layout of choke manifold. Flow field distribution and pressure drop are captured under different operating and structural conditions, and the effects of valve opening and inlet pressure are discussed in detail. The results indicate that flow field and pressure drop of choke manifold are both sensitive to inlet condition changes and structural changes. Among the four choke valves, wedge valve has the most severe erosion because it is at the turning of the whole manifold and its flow line deviates from the center of the pipe. Three flat valves have almost the same pressure drop. When the internal pressure increases from 40 to 70 MPa, the total pressure drop increases by 92.37%. However, pressure drop of wedge valve is lower than that of flat valve at the same opening degree. The work presented in this paper can provide a technological basis for flow characteristic study and structural improvement of choke manifold. [ABSTRACT FROM AUTHOR]

Frequently happening drill pipe failure accidents in oil and gas wells not only affect drilling speed, but cause enormous economic losses and many safety issues. Most of these accidents are transverse cracking of drill pipe body and pin thread or axial cracking of box thread. Based on the axial cracking failures of drill pipe body in an ultra-deep well in China, this paper give a systematic analysis of axial cracking failure in consideration of service condition, material quality and stress corrosion mechanism. Measurement and inspection are performed on macroscopic and microscopic morphology of crack surface, corrosion products and circumferential residual stress. Then stress corrosion cracking experiments against hydrogen sulfide is conducted. Finally, the critical stress value for sulfide stress corrosion cracking of the drill pipe material is obtained, and the mechanisms of axial cracking failure and corresponding preventive measures are proposed. [ABSTRACT FROM AUTHOR]

Direct conversion of methane to acetic acid with high activity and selectivity over non-noble metal-based catalysts under mild reaction conditions remains a grand challenge. Specifically, 1.2Ni-ZSM-5 with 88.9 % isolated Ni sites achieved a high acetic acid yield of 2920 μ mol/g cat. and a remarkable selectivity up to 82.3 % from methane oxidative carbonylation. Combined with high angle annular dark field scanning transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy analyses, it was revealed that the isolated Ni species with Ni-O 6 moieties anchored in the micropores of ZSM-5 were suggested to be the active sites. The isotopic labeling experiments and monitoring of reaction intermediates demonstrated that CH 3 COOH was formed via the direct coupling of methyl radicals and carbon monoxide molecules. This work suggests that the well-designed Ni sites can promote the transformation of CH 4 to C 2+ oxygenates instead of traditional C 1 oxygenates as main products. [Display omitted] • Non-noble Ni-based catalyst can promote the oxidative carbonylation of CH 4 to C 2+ oxygenates. • 2920 μ mol/g cat. of oxygenated products can be acquired with 82.3 % of CH 3 COOH selectivity. • The catalytic performance of Ni-ZSM-5 is comparable to these noble metal-based catalysts. • Isolated Ni sites anchored on zeolites was identified as active center. • The CH 3 COOH was formed via the direct coupling of ·CH 3 radicals and CO. [ABSTRACT FROM AUTHOR]

A green route for one−pot synthesis of acetals by tandem hydroformylation−acetalization of olefins using supported Rh−based catalysts was developed. Experimental results demonstrated that suitable Rh loading (1 wt%) with appropriate reaction temperature (120 °C) and reaction time (8 h) were favorable for the formation of acetals, and a high acetals selectivity of 94.6% was achieved. More importantly, the selectivity to valuable linear products was enhanced in this tandem catalysis. Based on the catalytic mechanism study, highly dispersed RhOx nanoparticles and abundant acid sites on the supports were responsible for the hydroformylation and acetalization, respectively. One-pot synthesis of acetals directly from olefins with high selectivity was achieved over heterogeneous bifunctional catalysts via tandem hydroformylation-acetalization. [ABSTRACT FROM AUTHOR]

Casing wear is a serious problem affecting casing integrity and casing strength, especially in ultra-deep wells, directional wells and horizontal wells. After casing is worn, degraded casing strength will lead to such hazardous problems as casing deformation, sustained casing pressure and even casing failure. Therefore, it is crucial and meaningful to predict residual casing strength and design casing string considering wear effect. Residual strength calculation model of worn casing, however, is still a challenge in casing design and safety evaluation. The purpose of this paper is to explore a simple and accurate model to predict the residual burst strength of crescent-shaped worn casing. The most commonly used mathematical models are discussed and compared in this paper. Through investigation and derivation, it is found that API (American Petroleum Institute) standard model assumes a uniform wear reduction around casing inner wall, while eccentric wear model simplifies worn casing as an eccentric pipe in bipolar coordinate. Then this paper presents a crescent-shaped wear model based on the force balance and moment balance of crescent-shaped worn casing. Finite element analysis proves that crescent-shaped wear model is more rigorous and accurate for residual burst strength prediction of worn casing. The work presented in this paper can provide a theoretical foundation and technical basis for casing wear evaluation and casing string design in directional wells. • A mathematical model for to predict the residual burst strength of crescent-shaped worn casing is established. • The most commonly used mathematical models are discussed and compared. • Finite element analysis is carried out and the distribution of hoop stress is studied. • Crescent-shaped wear model is more rigorous and accurate for residual burst strength prediction of worn casing. [ABSTRACT FROM AUTHOR]

Cu single atoms embedded in the C3N4 (Cu-SAs/C3N4) matrix exhibited high activity with 95% oxygenate selectivity for the direct conversion of methane at ambient temperature. The presence of abundant anchoring sites in C3N4 led to highly dispersed Cu–N4 moieties, which were suggested to be the underlying active sites for methane conversion. [ABSTRACT FROM AUTHOR]

Microseismic data and production logs in our study area have confirmed asymmetric developments of the stimulation rock volume in shales with respect to the wellbore, while severe casing deformation problems have been reported frequently in this area. Here, we propose a systematic methodology to investigate the possibility of casing failure due to strong shear stresses induced by asymmetric stimulated zones. A mechanical earth modeling (MEM) is initially performed to determine the in situ stress field in the target layer before fracturing by incorporating the existing geological features, logging data, and rock anisotropy. Then, we provide a computationally cheap and efficient estimation for stimulated rock volume of each stage by considering the possible overlaps in adjacent stages based on the clustered microseismic clouds. Using this approach, a reservoir‐scale 3D coupled model tied to a more detailed near‐wellbore part incorporating the casing string and the cement sheath is established to simulate the development of stimulation zones, stress redistribution, and their impacts on casing deformation as each stage fracturing treatment chronologically goes on. Our numerical results indicate that continuous redistribution and re‐orientation of stress field near the borehole are tracked during pumping the treatment which reveals formation of some pockets of tensile stresses along and around the wellbore. Asymmetric stimulations are observed to generate strong shear stress on the suspended casing. These shear forces result in deflection and S‐shape deformations accompanied with cross‐sectional ovality. Some regions receive repeating treatments, which results in intensifying formation stress heterogeneity and worsen casing deformation severity. The calculation results are compared with measurement of multi‐finger imaging tool (MIT) to validate the accuracy. Our analysis has indicated that simply increasing the flexural strength by increasing thickness of casing cannot radically mitigate casing deformation problems. This paper presents a novel workflow for a coupled modeling of casing deformation during hydraulic fracturing operations, while current modeling efforts assume symmetric bi‐wing fracture geometries. [ABSTRACT FROM AUTHOR]

Graphical abstract Morphology control of Co 2 C nanostructures via reduction process was developed for direct production of lower olefins from syngas. The structure-performance of the as-obtained Co 2 C nanoprisms and nanospheres were investigated based on kinetic study and DFT calculations. Highlights • Morphology control of Co 2 C nanostructures via reduction process was developed. • Co 2 C nanoprisms or nanospheres can be obtained by controlling the reduction process. • The structure-performance of the as-obtained Co 2 C nanoprisms and nanospheres was investigated. • Co 2 C nanoprisms possessed higher activity and lower methane selectivity than Co 2 C nanospheres. • The product distribution of Co 2 C nanoprisms deviated from the ASF law. Abstract Fischer-Tropsch to olefins (FTO) is recognized as a surface-catalyzed structure-sensitive reaction, and the catalytic performance is strongly influenced by the morphology and exposed facets of the active phase. Here we report the effect of the reduction process on the morphology of the active phase and the catalytic performance for FTO over the CoMn catalyst. For the catalysts reduced by 10% CO-300 °C, 10% H 2 -300 °C and 10% H 2 -250 °C, Co 2 C nanoprisms were formed after reaching the steady state. However, for the catalysts reduced by CO-300 °C and 10% H 2 -400 °C, Co 2 C nanospheres were found instead. Both Co 2 C nanoprisms and nanospheres were present for the spent sample reduced by 10% H 2 -350 °C. Kinetic study found Co 2 C nanospheres to possess higher activation energy, and are more sensitive to hydrogen than Co 2 C nanoprisms. Density functional theory (DFT) calculations were also performed to clarify the structure-performance relationship of Co 2 C nanostructures for syngas conversion. [ABSTRACT FROM AUTHOR]

Blooey line is a discharge pipe, used to conduct gas to keep drilling rock dust and cuttings away from the drilling rig, reducing the fire hazard and transporting the cuttings to a suitable distance from the well. In this paper, the blooey line's flow capacity and erosion mechanism have been investigated by numerical and experimental method. The model of blooey line, which is commonly used in Sichuan district, China, is established by using a computational fluid dynamics (CFD) method. And, the distribution of pressure field and velocity field in the blooey line are investigated by the CFD model. And, the effect of gas flow rate on impact force and erosion is also discussed. Compared with the simulation results, an experimental apparatus of the blooey line has been conducted under the mechanical similarity principle. The impact force and pressure on the elbows are measured under different gas flow rates. The numerical simulation and experimental method proposed in this paper can provide a reference for layout optimization and flow capacity calculation of blooey line in gas drilling. [ABSTRACT FROM AUTHOR]

A series of Co/ SiO2 catalysts with different sodium (Na) loadings (0, 0.1, 0.2, 0.5 and 1 wt%) were prepared and evaluated for Fischer-Tropsch reaction to study the effect of Na on the catalyst structure and catalytic performance. The addition of Na was found to decrease the catalytic activity and hydrocarbon selectivity, but increase CO2 selectivity due to the enhanced WGS activity. The addition of Na also resulted in higher selectivity to oxygenates (alcohols and aldehydes) and O/P ratio as well as the shift of hydrocarbons to lower carbon numbers. Structure characterization revealed a decrease in the surface area and particles size for the calcined samples with the addition of Na. Co2C was formed during the reaction process for the Na-promoted catalysts. As a result, a new Co/ Co2C bifunctional active sites were generated for oxygenates formation leading to increasing oxygenates selectivity. In addition, the Co2C nanoparticles alone may also act as dual active sites for oxygenate formation at high reaction pressure over the promoted catalysts with high Na loading. [ABSTRACT FROM AUTHOR]

Tuning Fischer-Tropsch synthesis products of metallic Co-based catalysts from paraffins to value-added olefins chemicals attracts great attention but remains challenging. Herein, we succeed in designing the carbon layers confined cobalt metal core-shell nanocatalyst (Co@C) via a reduction-carburization-pyrolysis (RCP) pretreatment of Co/SiO 2 , which exhibits highly efficient for Fischer-Tropsch to olefins (FTO) with negligible Water-Gas-Shift activity. At 250 °C and 5 bar, 56.4 % of olefins selectivity and limited CO 2 selectivity (5.8 %) are achieved for Mn-promoted Co@C nanocatalyst with at least 200 h of stability running. The electronic effect of carbon layers and Mn promoter as well as the confinement structure tailor the local chemical environment and weaken the hydrogenation ability of Co metal sites, thus improving the selectivity toward olefins while largely reducing the formation of CH 4 and CO 2. This work develops an effective strategy for the rational design of highly active and stable metallic Co-based FTO catalysts with high carbon efficiency. [Display omitted] • Carbon layers encapsulating Co metallic nanoparticles (Co@C) was successfully designed. • Reduction-carburization-pyrolysis (RCP) strategy was effective in fabricating Co@C structure. • Co@C nanocatalyst was favorable for olefins production instead of paraffins during FTS process. • Features of negligible WGSR activity and high carbon efficiency were observed for Co@C nanocatalyst. • Both electronic effect of carbon layers and Mn promoter could weaken hydrogenation ability of Co metal. [ABSTRACT FROM AUTHOR]

Selective conversion of syngas to olefins has aroused extensive attention while some challenges still existed such as high CO 2 selectivity. Herein, a series of hydrophobic FeMnO x @SiO 2 -y-(CH 3) 3 (y represents SiO 2 weight percent of the catalyst) catalysts with various SiO 2 shell content were synthesized for Fischer-Tropsch to olefins (FTO). During the activation process, high hydrophobic SiO 2 -coating content catalysts suppressed the reduction/carburization of iron species to iron carbide. During FTO reaction, iron carbide of low hydrophobic SiO 2 -coating content catalysts was re-oxidized while it was stabilized for high hydrophobic SiO 2 -coating content catalysts. The trade-off among CO 2 , CH 4 selectivity and SiO 2 -coating content was reflected as an increasing trend relationship, while olefins selectivity exhibited a decreasing trend. Additionally, a desirable hydrophobic SiO 2 -coating (8.2 wt%) catalyst apparently suppressed CO 2 formation (4.7 C%) with high olefins selectivity (54.6 C%) at CO conversion of 50.7%. This study provides an efficient approach to inhibit CO 2 formation of Fe-based FTO catalyst. [Display omitted] • Controllable hydrophobic SiO 2 shell of FeMnO x @SiO 2 catalysts were synthesized for FTO reaction. • The hydrophobic SiO 2 shell significantly decreased CO 2 selectivity by suppressing WGS reaction. • The hydrophobic SiO 2 shell content and olefins selectivity is reflected as a decreasing trend. [ABSTRACT FROM AUTHOR]

• This study investigates failure mechanisms for a wellhead Christmas tree. • A method combining physical and chemical analysis and numerical simulation analysis. • Erosion wear and corrosion wear were the mechanism of failure. The wellhead Christmas tree uses top sand drainage during multi-stage sanding fracturing, and it fails at the four-way and gate valves. Due to the multi-stage sanding fracturing process of a wellhead Christmas tree in an oilfield, the connection between the four-way and the gate valve flange failed for many times during service. In this paper, the failure causes of four-way flange joints were analyzed by reading spectrometer, Rockwell hardness tester, optical microscope, scanning electron microscope, energy dispersion spectrometer and numerical simulation method. The results show that the chemical composition, hardness and grain size of the four-way flange and connecting gate valve meet the standard requirements; By microstructural characterization and energy spectrum analysis, it is confirmed that a large number of corrosion products are attached to the inner wall of the four-way valve and gate valve; During the wellhead Christmas tree fracturing, high-speed sand-carrying fluid flows into the pipeline through four-way, and high-frequency multiple impacts occur to the connection of the four way flange and gate valve. At the same time, a large number of eddy current are formed at the intersection of the four-way and the gate valve flow channel. A large number of corrosion products distributed in the passage of the four-way valve and gate valve cause corrosion accumulation under the action of eddy current, forming corrosion wear, and finally the connection between the four way and the gate valve is damaged by erosion wear and corrosion wear. [ABSTRACT FROM AUTHOR]

The calcination pretreatment of SiO 2 support exhibited a significant effect on the structure-performance of supported Co 2 C-based catalyst for Fischer-Tropsch to olefins. [Display omitted] • Effect of thermal pretreatment of SiO 2 support on FTO performance was investigated. • Promising FTO performance was achieved if SiO 2 support was pretreated at 990 °C. • The morphology of Co 2 C nanostructures can be tuned by controlling pretreatment of support. • The Si OH content affects metal-support interaction and morphology of Co 2 C. SiO 2 supported Co 2 C-based catalysts were used for Fischer-Tropsch to olefins (FTO), and the effect of thermal pretreatment of SiO 2 support under different temperatures on the Co 2 C morphology and catalytic performance was investigated. It was found that the interaction between cobalt and support was weakened when SiO 2 was pretreated at high temperature (990 °C) due to the decreased content of surface Si OH groups. The relative weak interaction between cobalt and support benefited the formation of cobalt manganese composite oxide after calcination and reduction, and thus promoted the generation of Co 2 C nanoprisms with promising FTO performance. In contrast, for the SiO 2 support pretreated at 350 °C or 650 °C, the strong interaction between cobalt and support led to phase separation of cobalt and manganese. As a result, only Co 2 C nanospheres were generated which displayed low activity and high methane selectivity. [ABSTRACT FROM AUTHOR]

Abstract: Radial spherical ZnO structures with nanorods grown on both inside and outside of a hollow sphere-like core along the c-axis direction have been produced by thermal evaporation of Zn powder in the absence of catalysts. Scanning electron microscopy and X-ray diffraction investigation show that the radial spherical ZnO structures are of high purity nanocrystal with a wurtzite structure. It is found that the formation of the sphere-shaped liquid Zn droplets before adding oxygen is a key factor to control the morphology of the radial spherical ZnO structures. The radial spherical structures could possibly be used as a building block and open up new opportunities for the self-assembly of functional nanodevices. [Copyright &y& Elsevier]

• High selectivity to desired amines (93.2%) was obtained over 0.5Rh 1 /HAP catalyst. • Atomically dispersed Rh on HAP support was confirmed. • Single-atom Rh ensured high activity for hydroformylation step and tandem process. • A wide scope corresponding amines can be obtained with satisfactory yields. Tandem hydroaminomethylation is an efficient and green route for one-pot synthesis of amines directly from olefins. Herein, heterogeneous hydroxyapatite (HAP) supported single-atom Rh catalyst was prepared and used for tandem hydroaminomethylation of olefins. Characterization techniques confirmed the atomic dispersion of Rh species on HAP. Up to 99% conversion of 1-hexene with high selectivity to the desired amines (93.2%) was obtained over 0.5Rh 1 /HAP catalyst. Mechanism study demonstrated that the first hydroformylation step during the tandem catalytic process was rate-determining. Compared with the Rh nanoparticles on other oxide supports (Mg 3 Al, MgO and Al 2 O 3), the atomically dispersed Rh sites on HAP ensured the high hydroformylation activity, thereby guaranteed the outstanding catalytic performance for the total tandem process. Furthermore, various corresponding amines can be obtained with satisfactory yields over 0.5Rh 1 /HAP catalyst from a wide scope of olefins or amines substrates. [Display omitted] [ABSTRACT FROM AUTHOR]

• In order to obtain the basic data, a series of experiments are carried out. • In order to carry out the stress analysis of the absorber in detail. • The FEM of WOL sample is established to guide the work is high. • To assess the strength of the materials, SCC experiments are carried out. Pressure vessel is a primary barrier to gathering system and an important guarantee for normal production in the oilfield. Composite materials for pressure vessels are widely used to adapt to acidic media and temperature and pressure environment. Therefore, the stress corrosion cracking (SCC) is easily caused considering harsh working condition and multi-material structure. Pressure vessel defect due to SCC can cause material strength degradation, medium leakage and even explosion. In order to analyze the stress distribution of the whole equipment and verify the crack detection results in the field, a detailed finite elements model (FEM) of the absorber considering the composite material is established based on mechanical experiments and field data. On the other hand, a WOL specimen FEM is established according to the industry standard. Finally, twelve SCC evaluation experiments of composite materials are carried out based on the results of two established FEM, and the safety windows of 316L and SA516-70 are obtained in specific stress corrosion environments. The work presented in this paper can offer a technological basis and theoretical foundation for strength design of composite materials for pressure vessels in sour environment. [ABSTRACT FROM AUTHOR]