用于MTO装置中的乙炔选择加氢催化剂研究

在MTO工艺装置生产乙烯的过程中,乙烯中常含有50~200μL/L左右的微量乙炔,现有的石油烃蒸汽裂解制乙烯装置中常用的碳二加氢催化剂或适用于微量乙炔选择加氢的乙烯精制催化剂并不是MTO工艺中乙炔选择加氢的最好选择。通过研究Pd含量变化对催化剂性能的影响,发现降低Pd含量能够提高催化剂的乙烯选择性,降低催化剂的乙炔合格温度,在保证乙炔加氢合格的情况下,通过控制较低的氢炔比还能获得更好的乙烯选择性。通过添加适当的助剂,控制助剂的用量也能够提高催化剂的乙烯选择性。和商业碳二加氢催化剂BC2相比,采用浸渍法制备的BC2-MTO催化剂活性组分Pd含量降低了50%以上,活性金属Pd的分散度提高了69%,能够在较低的反应温度和氢炔比条件下使用,具有更好的催化活性和乙烯选择性。

MTO装置节能降耗研究与实施

从某MTO装置能耗占比结构分布情况,全面分析了装置的节能潜力。从装置智能化应用、设备改型、技术改造等三方面实施改造,从而达到降低MTO装置能耗的目标。

碳五回炼对甲醇制烯烃(MTO)反应性能的影响研究

甲醇制烯烃(MTO)装置副产混合碳五。为提高碳五组分的高值化利用,国能包头MTO装置采用再生催化剂输送管碳五回炼工艺。混合碳五预裂解增产乙烯和丙烯,同时实现对催化剂的预积碳,提高MTO催化剂活性。通过对比碳五回炼前后装置产出组分的差异,分析碳五回炼对MTO反应性能的影响,结果表明,乙烯和丙烯总收率提高1.03%,乙丙比(乙烯和丙烯比值)降低0.011,综合经济效益提高2 512元/h。

Co/SAPO-34催化剂在MTO反应中催化性能和积炭行为

针对SAPO-34分子筛在MTO反应中烯烃选择性低和易于酸性积炭失活的问题,通过等体积浸渍法向SAPO-34分子筛孔道内引入金属Co,系统考察了Co的加入量对Co/SAPO-34催化剂在MTO反应中的催化性能和积炭行为的影响。结果表明金属Co可以作为脱氢反应中心位点,削弱氢离子转移作用,抑制烷烃的生成,进而有效提高反应烯烃选择性;同时Co金属的引入可以精密调控SAPO-34分子筛表面酸中心强度,提高弱酸/强酸比例,进而削弱强酸中心的积炭作用,抑制催化剂的积炭失活。结合NH_(3)-TPD、H_(2)-TPD、氮气物理吸脱附、TG、XPS、GC-MS等表征方法,深入探讨Co/SAPO-34催化剂在MTO反应中的积炭行为,发现多甲基苯类关键积炭前体优先沉积于微孔和强酸位点,并显著促进稠环芳烃的生成,而相对较大的孔体积以及适量的弱酸浓度可以协同促进积炭前体的分解转化,抑制稠环芳烃等硬积炭物种的形成。积炭速率计算表明,具有适量酸性和孔道结构的Co 0.5/SAPO-34的甲醇转化率及低碳烯烃选择性最高,催化寿命最长。

MTO装置急冷水系统降固措施分析与评价

针对甲醇制烯烃(MTO)装置急冷水系统运行的瓶颈问题,以某年处理180万t甲醇的MTO装置为研究对象,结合装置近三年运行数据,分析了急冷水系统固含量高的原因,并对瓶颈问题进行了定性、定量分析。通过试用急冷水高温萃取剂、采用分离技术、耦合沉降罐与地下污水池技术、应用沸腾床过滤技术,使急冷水含固质量浓度降至1 000 mg/L,实现了急冷水系统平稳运行。

Modeling and analysis of air combustion and steam regeneration in methanol to olefins processes

Light olefins is the incredibly important materials in chemical industry.Methanol to olefins(MTO),which provides a non-oil route for light olefins production,received considerable attention in the past decades.However,the catalyst deactivation is an inevitable feature in MTO processes,and regeneration,therefore,is one of the key steps in industrial MTO processes.Traditionally the MTO catalyst is regenerated by removing the deposited coke via air combustion,which unavoidably transforms coke into carbon dioxide and reduces the carbon utilization efficiency.Recent study shows that the coke species over MTO catalyst can be regenerated via steam,which can promote the light olefins yield as the deactivated coke species can be essentially transferred to industrially useful synthesis gas,is a promising pathway for further MTO processes development.In this work,we modelled and analyzed these two MTO regeneration methods in terms of carbon utilization efficiency and technology economics.As shown,the steam regeneration could achieve a carbon utilization efficiency of 84.31%,compared to 74.74%for air combustion regeneration.The MTO processes using steam regeneration can essentially achieve the near-zero carbon emission.In addition,light olefins production of the MTO processes using steam regeneration is 12.81%higher than that using air combustion regeneration.In this regard,steam regeneration could be considered as a potential yet promising regeneration method for further MTO processes,showing not only great environmental benefits but also competitive economic performance.

Precision tuning of highly efficient Pt-based ternary alloys on nitrogen-doped multi-wall carbon nanotubes for methanol oxidation reaction

The electrochemical methanol oxidation is a crucial reaction in the conversion of renewable energy.To enable the widespread adoption of direct methanol fuel cells(DMFCs),it is essential to create and engineer catalysts that are both highly effective and robust for conducting the methanol oxidation reaction(MOR).In this work,trimetallic PtCoRu electrocatalysts on nitrogen-doped carbon and multi-wall carbon nanotubes(PtCoRu@NC/MWCNTs)were prepared through a two-pot synthetic strategy.The acceleration of CO oxidation to CO_(2) and the blocking of CO reduction on adjacent Pt active sites were attributed to the crucial role played by cobalt atoms in the as-prepared electrocatalysts.The precise control of Co atoms loading was achieved through precursor stoichiometry.Various physicochemical techniques were employed to analyze the morphology,element composition,and electronic state of the catalyst.Electrochemical investigations and theoretical calculations confirmed that the Pt_(1)Co_(3)Ru_(1)@NC/MWCNTs exhibit excellent electrocatalytic performance and durability for the process of MOR.The enhanced MOR activity can be attributed to the synergistic effect between the multiple elements resulting from precisely controlled Co loading content on surface of the electrocatalyst,which facilitates efficient charge transfer.This interaction between the multiple components also modifies the electronic structures of active sites,thereby promoting the conversion of intermediates and accelerating the MOR process.Thus,achieving precise control over Co loading in PtCoRu@NC/MWCNTs would enable the development of high-performance catalysts for DMFCs.

Efficient and stable PtFe alloy catalyst for electrocatalytic methanol oxidation with high resistance to CO

Direct methanol fuel cells(DMFC) are widely considered to be an ideal green energy conversion device but their widespread applications are limited by the high price of the Pt-based catalysts and the instability in terms of surface CO toxicity in long-term operation.Herein,the PtFe alloy nanoparticles(NPs) with small particle size(~4.12 nm) supported on carbon black catalysts with different Pt/Fe atomic ratios(Pt_(1)Fe_(2)/C,Pt_(3)Fe_(4)/C,Pt_(1)Fe_(1)/C,and Pt_(2)Fe_(1)/C) are successfully prepared for enhanced anti-CO poisoning during methanol oxidation reaction(MOR).The optimal atomic ratio of Pt/Fe for the MOR is 1:2,and the mass activity of Pt_(1)Fe_(2)/C(5.40 A mg_(Pt)^(-1)) is 13.5 times higher than that of conventional commercial Pt/C(Pt/C-JM)(0.40 A mg_(Pt)^(-1)).The introduction of Fe into the Pt lattice forms the PtFe alloy phase,and the electron density of Pt is reduced after forming the PtFe alloy.In-situ Fourier transform infrared results indicate that the addition of oxyphilic metal Fe has reduced the adsorption of reactant molecules on Pt during the MOR.The doping of Fe atoms helps to desorb toxic intermediates and regenerate Pt active sites,promoting the cleavage of C-O bonds with good selectivity of CO_(2)(58.1%).Moreover,the Pt_(1)Fe_(2)/C catalyst exhibits higher CO tolerance,methanol electrooxidation activity,and long-term stability than other Pt_(x)Fe_(y)/C catalysts.

Realizing methanol synthesis from CO and water via the synergistic effect of Cu^(0)/Cu^(+)over Cu/ZrO_(2) catalyst

The optimizing utilization of ca rbon resources has drawn wide attention all over the world,while exploiting the high-efficiency catalytic routes remains a challenge.Here,a direct methanol synthesis route is realized from pure CO and H_(2)O over 10%Cu/t-ZrO_(2) catalyst,where the time yield of methanol is144.43 mmol mol_(Cu)^(-1)h^(-1)and the methanol selectivity in hydrocarbons is 100%,The Cu species highly dispersed in the t-ZrO_(2) support lead parts of them in the cationic state.The Cu^(+)sites contribute to the dissociation of H_(2)O,providing the H*source for methanol synthesis,while the formed Cu^(0) sites promote the absorption and transfer of H*during the reaction.Moreover,the H_(2)O is even a better H resource than H_(2) due to its better dissociation effectivity in this catalytic system.The present work offers a new approach for methanol synthesis from CO and new insight into the process of supplying H donor.

Interfacial Electronic Modulation of Dual-Monodispersed Pt–Ni_(3)S_(2) as Efficacious Bi-Functional Electrocatalysts for Concurrent H_(2) Evolution and Methanol Selective Oxidation

Constructing the efficacious and applicable bifunctional electrocatalysts and establishing out the mechanisms of organic electro-oxidation by replacing anodic oxygen evolution reaction(OER) are critical to the development of electrochemicallydriven technologies for efficient hydrogen production and avoid CO_(2) emission. Herein, the hetero-nanocrystals between monodispersed Pt(~ 2 nm) and Ni_(3)S_(2)(~ 9.6 nm) are constructed as active electrocatalysts through interfacial electronic modulation, which exhibit superior bi-functional activities for methanol selective oxidation and H_(2) generation. The experimental and theoretical studies reveal that the asymmetrical charge distribution at Pt–Ni_(3)S_(2) could be modulated by the electronic interaction at the interface of dual-monodispersed heterojunctions, which thus promote the adsorption/desorption of the chemical intermediates at the interface. As a result, the selective conversion from CH_(3)OH to formate is accomplished at very low potentials(1.45 V) to attain 100 m A cm^(-2) with high electronic utilization rate(~ 98%) and without CO_(2) emission. Meanwhile, the Pt–Ni_(3)S_(2) can simultaneously exhibit a broad potential window with outstanding stability and large current densities for hydrogen evolution reaction(HER) at the cathode. Further, the excellent bi-functional performance is also indicated in the coupled methanol oxidation reaction(MOR)//HER reactor by only requiring a cell voltage of 1.60 V to achieve a current density of 50 m A cm^(-2) with good reusability.

The Effects of the Geometry of a Current Collector with an Equal Open Ratio on Output Power of a Direct Methanol Fuel Cell

The open ratio of a current collector has a great impact on direct methanol fuel cell(DMFC)performance.Although a number of studies have investigated the influence of the open ratio of DMFC current collectors,far too little attention has been given to how geometry(including the shape and feature size of the flow field)affects a current collector with an equal open ratio.In this paper,perforated and parallel current collectors with an equal open ratio of 50%and different feature sizes are designed,and the corresponding experimental results are shown to explain the geometry effects on the output power of the DMFC.The results indicate that the optimal feature sizes are between 2 and 2.5 mm for both perforated and parallel flow field in the current collectors with an equal open ratio of 50%.This means that for passive methanol fuel cells,to achieve the highest output power,the optimal feature size of the flow field in both anode and cathode current collectors is between 2 and 2.5 mm under the operating mode of this experiment.The effects of rib and channel position are also investigated,and the results indicate that the optimum pattern depends on the feature sizes of the flow field.

从基础研究到工业转化应用的实践——甲醇制烯烃SMTO催化技术开发

煤基甲醇制烯烃(MTO)是煤炭清洁利用的关键技术之一,对于保障国家能源安全具有重要的战略意义。中国石油化工集团有限公司经过20余年的研究,在催化反应机制、高性能分子筛催化剂以及反应-再生工艺技术等方面持续创新,开发了高效甲醇制烯烃SMTO工艺技术,实现了从导向性基础研究到工业应用的贯通式创新。

CO_(2) hydrogenation to methanol over the copper promoted In_(2)O_(3) catalyst

The metal promoted In_(2)O_(3) catalysts for CO_(2) hydrogenation to methanol have attracted wide attention because of their high activity with high methanol selectivity.However,there was still no experimental confirmation if copper could be a good promoter for In_(2)O_(3).Herein,the Cu promoted In_(2)O_(3) catalyst was prepared using a deposition-precipitation method.Such prepared Cu/In_(2)O_(3) catalyst shows significantly higher CO_(2) conversion and space time yield(STY)of methanol,compared to the un-promoted In_(2)O_(3) catalyst.The loading of Cu facilitates the activation of both H_(2) and CO_(2) with the interface between the Cu cluster and defective In_(2)O_(3) as the active site.The Cu/In_(2)O_(3) catalyst takes the CO hydrogenation pathway for methanol synthesis from CO_(2) hydrogenation.It exhibits a unique size effect on the CO adsorption.At temperatures below 250℃,CO adsorption on Cu/In_(2)O_(3) is stronger than that on In_(2)O_(3),causing higher methanol selectivity.With increasing temperatu res,the Cu catalyst aggregates,which leads to the formation of weak CO adsorption site and causes a decrease in the methanol selectivity.Compared with other metal promoted In_(2)O_(3) catalysts,it can be concluded that the catalyst with stronger CO adsorption possesses higher methanol selectivity.

Pt nanoclusters modified porous g-C_(3)N_(4)nanosheets to significantly enhance hydrogen production by photocatalytic water reforming of methanol

For the use of green hydrogen energy,it is crucial to have efficient photocatalytic activity for hydrogen generation by water reforming of methanol under mild conditions.Much attention has been paid to gC_(3)N_(4)as a promising photocatalyst for the generation of hydrogen.To improve the separation of photogenerated charge,porous nanosheet g-C_(3)N_(4)was modified with Pt nanoclusters(Pt/g-C_(3)N_(4))through impregnation and following photo-induced reduction.This catalyst showed excellent photocatalytic activity of water reforming of methanol fo r hydrogen production with a 17.12 mmol·g^(-1)·h^(-1)rate at room temperature,which was 311 times higher than that of the unmodified g-C_(3)N_(4).The strong interactions of Pt-N in Pt/g-C_(3)N_(4)constructed effective electron transfer channels to promote the separation of photogenerated electrons and holes effectively.In addition,in-situ infrared spectroscopy was used to investigate the intermediates of the hydrogen production reaction,which proved that methanol and water eventually turn into H_(2)and CO_(2)via formaldehyde and formate.This study provides insights for understanding the photocatalytic hydrogen production in the water reforming of methanol.

MTO装置再生器旋风分离器操作优化模拟研究

旋风分离器是甲醇制烯烃(MTO)装置常用的气固两相分离设备,其分离效率对装置的长周期稳定运行非常重要。某0.6 Mt/a MTO装置采用高活性催化剂后,再生器烧焦主风量低于设计值,导致一级旋风分离器入口气速低,20μm以下细粉催化剂跑损量增大,催化剂消耗量增大。为此,采用计算颗粒流体力学(CPFD)软件模拟再生器四组二级旋风分离器的不同操作工况,调整旋风分离器入口面积与烟气流量改变入口气速,研究入口气速对旋风分离器压降和分离效率的影响规律。结果表明:烟气流量为42241 m^(3)/h时,封闭一组一级入口,旋风分离器入口气速提高3 m/s,旋风分离器总效率提高0.501百分点。依据模拟结果对旋风分离器提出了优化操作建议,可推广应用于其他MTO装置的操作调整。

Chemical profiling of bioactive compounds in the methanolic extract of wild leaf and callus of Vitex negundo using gas chromatographymass spectrometry

BACKGROUND The investigation of plant-based therapeutic agents in medicinal plants has revealed their presence in the extracts and provides the vision to formulate novel techniques for drug therapy.Vitex negundo(V.negundo),a perennial herb belonging to the Varbanaceae family,is extensively used in conventional medication.AIM To determine the existence of therapeutic components in leaf and callus extracts from wild V.negundo plants using gas chromatography-mass spectrometry(GCMS).METHODS In this study,we conducted GC-MS on wild plant leaf extracts and correlated the presence of constituents with those in callus extracts.Various growth regulators such as 6-benzylaminopurine(BAP),2,4-dichlorophenoxyacetic acid(2,4-D),α-naphthylacetic acid(NAA),and di-phenylurea(DPU)were added to plant leaves and in-vitro callus and grown on MS medium.RESULTS The results clearly indicated that the addition of BAP(2.0 mg/L),2,4-D(0.2 mg/mL),DPU(2.0 mg/L)and 2,4-D(0.2 mg/mL)in MS medium resulted in rapid callus development.The plant profile of Vitex extracts by GC-MS analysis showed that 24,10,and 14 bioactive constituents were detected in the methanolic extract of leaf,green callus and the methanolic extract of white loose callus,respectively.CONCLUSION Octadecadienoic acid,hexadecanoic acid and methyl ester were the major constituents in the leaf and callus methanolic extract.Octadecadienoic acid was the most common constituent in all samples.The maximum concentration of octadecadienoic acid in leaves,green callus and white loose callus was 21.93%,47.79%and 40.38%,respectively.These findings demonstrate that the concentration of octadecadienoic acid doubles in-vitro compared to in-vivo.In addition to octadecadienoic acid;butyric acid,benzene,1-methoxy-4-(1-propenyl),dospan,tridecanedialdehyde,methylcyclohexenylbutanol,chlorpyrifos,n-secondary terpene diester,anflunine and other important active compounds were also detected.All these components were only available in callus formed in-vitro.This study showed that the callus contained additional botanical characteristics compared with wild plants.Due to the presence of numerous bioactive compounds,the medical use of Vitex for various diseases has been accepted and the plant is considered an important source of therapeutics for research and development.

MTO-Ⅲ装置中催化剂管道设计

MTO装置在煤制烯烃工艺过程中起到承上启下的关键作用。MTO装置反应-再生系统中的催化剂管道设计的好坏又是装置能否长周期高效运行的关键环节。结合实际设计经验简单介绍了什么是MTO-Ⅲ装置、催化剂管道在装置中的作用、催化剂管道的特点、设计原则、设计条件、元件选择及其辅助管道的典型配管等。希望通过催化剂管道设计过程的分享,能对同类设计起到抛砖引玉的作用,尤其催化剂管道材质的选择和催化剂输送辅助管道的配管方式等值得大家共同探讨。

DMTO:A Sustainable Methanol-to-Olefins Technology

1.Introduction Ethylene and propylene are the cornerstones of the chemical industry,with more than 75%of chemical products as their downstream derivatives.They are conventionally produced via naphtha steam cracking and fluid catalytic cracking(FCC),in which oil is mainly used as feedstock.China,however,relies heavily on imports for crude oil.The Dalian Institute of Chemical Physics(DICP),together with China Petroleum&Chemical Corporation(Sinopec)Luoyang Petrochemical Engineering Company and SYN Energy Technology Co.,Ltd.,have developed a methanol-to-olefins technology—namely DMTO—which opens up an alternative path to synthesize light olefins from methanol,a platform chemical that can be readily derived from coal[1].As coal is relatively abundant in China,the success of DMTO is of practical significance in balancing the supply and demand of light olefins,reducing China’s dependence on imports for crude oil,and promoting national energy security.This report outlines the catalyst,fluidized-bed reactor,and process of DMTO technology,with an emphasis on the key technologies involved in commercial units and sustainable development for future applications.

空壳型SAPO-34分子筛催化剂的制备及催化MTO反应

采用复合模板剂合成出具有空壳结构的SAPO-34分子筛。使用XRD、SEM、BET对合成的分子筛样品进行表征,结果表明,所合成的分子筛为空壳型纯相SAPO-34分子筛,比表面积达到638.59 m^(2)/g。在催化甲醇制烯烃反应中,甲醇转化率达到100%,乙烯和丙烯(双烯)选择性达到85.3%。催化剂单程寿命为28 min,是常规SAPO-34分子筛的1.75倍。空壳型SAPO-34分子筛具有优异的MTO催化性能,主要原因是缩短了反应产物从分子筛孔道扩散出来的路径,减少了产物二次反应的发生。

Kinetics of steam regeneration of SAPO-34 zeolite catalyst in methanol-to-olefins(MTO) process

Methanol-to-olefins(MTO)is industrially applied to produce ethylene and propylene using methanol converted from coal,synthetic gas,and biomass.SAPO-34 zeolites,as the most efficient catalyst in MTO process,are subject to the rapid deactivation due to coke deposition.Recent work shows that steam regeneration can provide advantages such as low carbon dioxide emission and enhanced light olefins yield in MTO process,compared to that by air regeneration.A kinetic study on the steam regeneration of spent SAPO-34 catalyst has been carried out in this work.In doing so,we first investigated the effect of temperature on the regeneration performance by monitoring the crystal structure,acidity,residual coke properties and other structural parameters.The results show that with the increase of regeneration temperature,the compositions of residual coke on the catalyst change from pyrene and phenanthrene to naphthalene,which are normally considered as active hydrocarbon pool species in MTO reaction.However,when the regeneration temperature is too high,nitrogen oxides can be found in the residual coke.Meanwhile,as the regeneration temperature increases,the quantity of residual coke reduces and the acidity,BET surface area and pore structure of the regenerated samples can be better recovered,resulting in prolonging catalyst lifetime.We have further derived the kinetics of steam regeneration,and obtained an activation energy of about 177.8 kJ·mol^(-1).Compared that with air regeneration,the activation energy of steam regeneration is higher,indicating that the steam regeneration process is more difficult to occur.