Excitation and ionization of OCS molecules in strong UV and NIR laser fields

Rydberg state excitation(RSE) is a highly non-linear physical phenomenon that is induced by the ionization of atoms or molecules in strong femtosecond laser fields. Here we observe that both parent and fragments(S, C, OC) of the triatomic molecule carbonyl sulfide(OCS) can survive strong 800 nm or 400 nm laser fields in high Rydberg states. The dependence of parent and fragment RSE yields on laser intensity and ellipticity is investigated in both laser fields, and the results are compared with those for strong-field ionization. Distinctly different tendencies for laser intensity and ellipticity are observed for fragment RSE compared with the corresponding ions. The mechanisms of RSE and strong-field ionization of OCS molecules in different laser fields are discussed based on the experimental results. Our study sheds some light on the strong-field excitation and ionization of molecules irradiated by femtosecond NIR and UV laser fields.

Simultaneous catalytic hydrolysis of carbonyl sulfide and carbon disulfide over Al_2O_3-K/CAC catalyst at low temperature

In this work, a series of coal-based active carbon （CAC） catalysts loaded by A1203 were prepared by sol-gel method and used for the simulta- neous catalytic hydrolysis of carbonyl sulfide （COS） and carbon disulfide （CS2） at relatively low temperatures of 30-70 ℃. The influences of calcinations temperatures and operation conditions such as： reaction temperature, 02 concentration, gas hourly space velocity （GHSV） and relative humidity （RH） were also discussed respectively. The results showed that catalysts with 5.0 wt% A1203 calcined at 300 ℃ had supe- rior activity for the simultaneous catalytic hydrolysis of COS and CS2. When the reaction temperature was above 50 ℃, catalytic hydrolysis activity of COS could be enhanced but that of CS2 was inhibited. Too high RH could make the catalytic hydrolysis activities of COS and CS2 decrease. A small amount of 02 introduction could enhance the simultaneous catalytic hydrolysis activities of COS and CS2.

Removal of carbonyl sulfide from CO_2 stream using AgNO_3-modified NaZSM-5

Removal of carbonyl sulfide(COS) from CO2 stream is significant for the production and utilization of food grade CO2. This study investigates the adsorption performance of Ag/NaZSM-5 as adsorbent prepared by incipient wetness impregnation for the removal of COS from a CO2 stream in a fixed-bed adsorption apparatus. Effects of various conditions on the preparation of adsorbent, adsorption and desorption were intensively examined. The results revealed that COS can be removed to below 1×10-9from a CO2stream(1000 ppm COS/CO2) using Ag/NaZSM-5(10 wt% AgNO3) with an adsorption capacity of 12.86 mg·g-1. The adsorbent can be fully regenerated using hot air at 450 C. The adsorption ability remained stable even after eight cycles of regeneration.

Hydrolysis of Carbonyl Sulfide in Binary Mixture of Diethylene Glycol Diethyl Ether and Water

The solubility and hydrolysis of carbonyl sulfide in binary mixture of diethylene glycol diethyl ether and water are studied as a function of composition. The use of an aqueous solution of diethylene glycol diethyl ether enhances the solubility and hydrolysis rate of carbonyl sulfide compared with that in pure water. The composition of the mixture with maximum hydrolysis rate varies with temperature. The thermophysical properties including density, viscosity, and surface tension as a function of composition at 20℃ under atmospheric pressure as well as liquid-liquid equilibrium (LLE) data over the temperature range from 28℃ to 90℃ are also measured for the binary mixture.

Tuning the growth of Cu-MOFs for efficient catalytic hydrolysis of carbonyl sulfide

Development of the high activity,promoter‐free catalysts for carbonyl sulfide(COS)hydrolysis is important for the efficient utilization of various feedstocks.In this study,the Cu‐based metal‐organic framework HKUST‐1is synthesized by a simple and mild anodic‐dissolution electrochemical method.The physical and chemical properties of the samples are characterized by several techniques,including scanning electron microscopy,X‐ray diffraction,Brunauer‐Emmett‐Teller analysis and X‐ray photoelectron spectroscopy.The results reveal that the synthesis voltage plays a crucial role in controlling the morphology of the resulting HKUST‐1.The obtained samples function as novel catalysts for the hydrolysis of COS.A high efficiency,approaching100%,can be achieved for the conversion of COS at150oC over the optimal HKUST‐1synthesized at25V.This is significantly higher than that of the sample prepared by the traditional hydrothermal method.Additionally,the effects of the water temperature and the flow velocity on the hydrolysis of COS are also investigated in detail.Finally,a possible reaction pathway of COS hydrolysis over HKUST‐1is also proposed.This work represents the first example of MOFs applied to the catalytic hydrolysis of COS.The results presented in this study can be anticipated to give a feasible impetus to design novel catalysts for removing the sulfur‐containing compounds.

Catalytic hydrolysis of carbonyl sulfide over modified coal-based activated carbons by loading metal

A novel type of metal oxide/activated carbon catalyst was prepared by sol-gel method for the hydrolysis of carbonyl sulfide （COS）. The influences of the calcination temperature, additive content （2.5%-10.0% Fe2O3, mass fraction） and the basic density of the activation process were thoroughly investigated. The surface of catalysts was characterized by Boehm titration. The products were characterized by scanning electron microscopy （SEM）, X-ray diffractometry （XRD） and X-ray photoelectron spectroscopy （XPS）. The results show that catalysts with 2.5%-5.0% Fe2O3 after calcining at 500 ℃ have superior activity. The conversion rate of COS increases with increasing the relative density of basic capacity loaded onto activated carbon（AC）, and the activity follows the order： KOH〉Na2CO3 〉NaHCO3. Boehm titration data clearly show that the total acidity increases （from 0.06 to 0.48 mmol/g） and the basic groups decrease （from 0.78 to 0.56 mmol/g） after COS hydrolysis and H2S adsorption. The XPS results show that the product of HzS may be absorbed by the interaction with metal compounds and 02 to form sulfate （171.28 eV） and element sulfur （164.44 eV）, which lead to catalysts poisoning.

A Novel Sulfided Mo/C Catalyst for Direct Vapor Phase Carbonylation of Methanol at Atmospheric Pressure

The direct carbonylation of methanol, without any halide in the feed as apromoter, is presented. A series of Mo catalysts supported on activated carbon, γ-Al_2O_3 and SiO_2were prepared. The results show that the support greatly affects the Mo catalyst in the directvapor-phase carbonylation of methanol, and activated carbon is the best supports of the investigatedsupports. In addition, the relationships between adsorptions of NH_3 and CO and carbonylation ofmethanol were investigated. A novel sulfided Mo/C catalyst had high activity and selectivity for thevapor phase carbonylation of methanol to methyl acetate without the addition of a CH_3I promoter tothe feed. The reaction conditions were optimized at a reaction temperature of 573 K, a methanolconcentration of 23 mol% and a carbon monoxide space velocity of 3,000 L/(kg·h). Under theseoptimal conditions a methanol conversion of 50%, carbonylation selectivity of 80 rnol%, andspace-time yield of 8.0 mol/(kg·h) were obtained. The active phase of this novel sulfided Mo/Ccatalyst is the non-crystalline phase, and the active component is present as MoS_(2.5) on thesurface of the activated carbon.

The Study of the Preparation of Catalysts for Carbonyl Sulfide Hydrolysis under Moderate Temperature

Multifunctional composite catalyst for carbonyl sulfide hydrolysis under moderate temperature was prepared by impregnation method. The hydrolysis and deoxidization ability of the prepared catalyst was investigated in a fixed bed reactor. It was found that deoxidization ability of the prepared catalyst was raised by the increase of the content of potassium loading catalyst and reaction temperature. And the concentration of H2S had no effect on deoxidization while COS improved the deoxidization ratio. And deoxidization rates were nearly scaled up with concentration of H2. The hydrolysis ability was decreased by the decrease of the surface basicity.

Influence of Gas Components on the Formation of Carbonyl Sulfide over Water-Gas Shift Catalyst B303Q

Water-gas shift reaction catalyst at lower temperature （200-400 ℃） may improve the conversion of carbon monoxide. But carbonyl sulfide was found to be present over the sulfided cobaltmolybdenum/alumina catalyst for water-gas shift reaction. The influences of temperature, space velocity, and gas components on the formation of carbonyl sulfide over sulfided cobalt-molybdenum/alumina catalyst B303Q at 200-400 ℃ were studied in a tubular fixed-bed quartz-glass reactor under simulated water-gas shift conditions. The experimental results showed that the yield of carbonyl sulfide over B303Q catalyst reached a maximum at 220 ℃ with the increase in temperature, sharply decreased with the increase in space velocity and the content of water vapor, increased with the increase in the content of carbon monoxide and carbon dioxide, and its yield increased and then reached a stable value with the increase in the content of hydrogen and hydrogen sulfide. The formation mechanism of carbonyl sulfide over B303Q catalyst at 200-400 ℃ was discussed on the basis of how these factors influence the formation of COS. The yield of carbonyl sulfide over B303Q catalyst at 200-400 ℃ was the combined result of two reactions, that is, COS was first produced by the reaction of carbon monoxide with hydrogen sulfide, and then the as-produced COS was converted to hydrogen sulfide and carbon dioxide by hydrolysis. The mechanism of COS formation is assumed as follows： sulfur atoms in the Co9Ss-MoS2/Al2O3 crystal lattice were easily removed and formed carbonyl sulfide with CO, and then hydrogen sulfide in the water-gas shift gas reacted with the crystal lattice oxygen atoms in CoO-MoOa/Al2O3 to form Co9S8-MoS2/Al2O3. This mechanism for the formation of COS over water-gas shift catalyst B303Q is in accordance with the Mars-Van Krevelen＇s redox mechanism over metal sulfide.

秸杆燃烧中OCS的排放因子和排放估算

建立了痕量羰基硫采样及分析方法，利用低温预捕集和被捕集样直接释放进入分离柱技术，对压缩空气进行采样测定，得出了压缩空气中ＯＣＳ约在２．９４×１０－３μｇ／Ｌ，方法精确度以标准误差系数计为±０．７２％。利用此采样及分析方法对实验室规模的生物质封闭燃烧系统，稻草、玉米秸、麦杆燃烧过程中排出痕量ＯＣＳ进行了采样分析，得出稻草、玉米秸、麦杆燃烧排气中ＯＣＳ的排放量，以排放因子表示分别是：１．８０ｇ／ｔ，２．７５ｇ／ｔ，２．０５ｇ／ｔ。详细统计了作物秸杆量，建立了全国各县各种作物秸杆燃烧释放痕量气总体和网格排放计算的数学模式。利用排放因子计算了几种主要作物秸杆燃气中ＯＣＳ的释放量。

OCS的多光子电离高分辨光电子能谱

Using a Nd:YAG pumped pulsed dye laser-wavelength extender as UV light source, the multiphoton ionization of o CS was studied in a supersonic moecular beam with a Time of Flight mass spectrometer and a Magnetic Bottle Time of Flight photoelectron spectrometer. The intermediate resonant states of OCS were obtained from the massselected MPI spectra by scanning the laser wavelength. From 2+1 MPI photoelectron spectra at dmerent resonant wavelength the vibrational levels of OCS+ ion in electronic ground state X2 H3/2,1/2 were assigned and their X2II spin-orbital splitting was determined to be 0.046eV. The non Franck-Condon behavior between the Rydberg intermediate state and the ionic state has been discussed.

Photodissociation Dynamics of OCS at 207 nm:S(1D2)+CO(X^1Σ^+)Product Channel

By using the direct current slice velocity map imaging technique,the polarization experiment for S(1D2)product from the ultraviolet photodissociation of carbonyl sulfide at 207 nm was studied.The angular momentum polarization character of the photofragment S(1D2)was detected via two different resonance enhanced multiphoton ionization intermediate states,1F3 and 1P1,and four different pump-probe laser polarization geometries.The angular distribution of the corresponding CO(X^1Σ^+)coproducts was extracted and analyzed using the molecular-frame polarization and the laboratory-frame anisotropy models.The observed total kinetic energy release spectrum indicates that there are three dissociation channels,corresponding to the low,medium,and high kinetic energy.The sources of the low and medium kinetic energy channels are consistent with those of bimodal translational energy distribution at longer photolysis wavelengths.The high kinetic energy channel is a new dissociation channel arising from the direct dissociation from the single repulsive A(2^1A′)state.

Vacuum Ultraviolet Photodissociation Dynamics of OCS via the F Rydberg State:theS(^(3)P_(J=2,1,0))Product Channels

Vacuum ultraviolet(VUV)photodissociation dynamics of carbonyl sulfide was investigated experimentally by using a tunable photolysis light source and the timesliced velocity map ion imaging technique.Ion images of S(^(3)P_(J=2,1,0))dissociation products were measured at five photolysis wavelengths from 133.26 nm to 139.96 nm,corresponding to the F Rydberg state of OCS.Two dissociation channels:S(^(3)P_(J))+CO(X^(1)Σ+)and S(^(3)P_(J))+CO(A^(3)Π)were observed with the former being dominant.The vibrational states of CO co-products were partially resolved in the ion images.The product total kinetic energy releases,anisotropy parameters(β),and the branching ratios of high-lying CO vibrational states were determined for the S(^(3)P_(J))+CO(X^(1)Σ^(+))channel.We found that the anisotropy parameters suddenly changed from negative to positive when OCS was excited to the higher vibrational levels of the F state.Furthermore,the anisotropy parameters for S(^(3)P_(J))products of J=2,1,0 were even different.These anomalous phenomena may result from the simultaneous existence of both parallel and perpendicular dissociation mechanisms,suggesting the involvement of other electronic states with different symmetry in the initially-excited energy region.This work provides a further understanding of the nonadiabatic couplings in the VUV photodissociation process of OCS.

Wavelength Dependent Photodissociation of OCS via F 3^1ПRydberg State:CO(X1+)+S(1D2)Product Channel

The vacuum ultraviolet photodissociation of OCS via the F 3^1ΠRydberg states was investigated in the range of 134-140 nm by means of the time-sliced velocity map ion imaging technique.The images of S(^1D2)products from the CO(X^1Σ^+)+S(^1D2)dissociation channel were acquired at five photolysis wavelengths,corresponding to a series of symmetric stretching vibrational excitations in OCS(F 3^1Π,v1=0-4).The total translational energy distributions,vibrational populations and angular distributions of CO(X^1Σ^+,v)coproducts were derived.The analysis of experimental results suggests that the excited OCS molecules dissociate to CO(X^1Σ^+)and S(^1D2)products via non-adiabatic couplings between the upper F 3^1Πstates and the lower-lying states both in the C∞v and Cs symmetry.Furthermore,strong wavelength dependent behavior has been observed:the greatly distinct vibrational populations and angular distributions of CO(X^1Σ^+,v)products from the lower(v1=0-2)and higher(v1=3,4)vibrational states of the excited OCS(F 3^1Π,v1)demonstrate that very different mechanisms are involved in the dissociation processes.This study provides evidence for the possible contribution of vibronic coupling and the crucial role of vibronic coupling on the vacuum ultraviolet photodissociation dynamics.

Photodissociation Dynamics of OCS Near 128 nm:S(3PJ=2,1,0),S(1D2)and S(1S0)Channels

Here we report the study of the photodissociation dynamics of carbonyl sulfide in the vacuum ultraviolet region using the time-sliced velocity map ion imaging technique.Images of S(^3PJ=2,1,0),S(^1D2)and S(^1S0)products were measured at four photolysis wave-lengths of 129.32,128.14,126.99,and 126.08 nm,respectively.Four main dissociation channels:S(^3PJ=2,1,0)+CO(X^1Σ^+),S(^3PJ=2,1,0)+CO(A^3π),S(^1D2)+CO(X^1Σ^+)and S(^1S0)+CO(X^1Σ^+)channels,have been clearly observed and identified.Vibrational states of the CO co-products were partially resolved in the experimental images.From these images,the product total kinetic energy releases,the branching ratios and angular distributions of products have been derived.While the S(^3PJ=2,1,0)+CO(A^3π)product channel is formed through the adiabatic dissociation process after the excitation to the(3^1Σ^+)excited state,the results suggest that strong nonadiabatic coupling plays an important role in the formation of other three channels.

天然气中二氧化碳与羰基硫脱除机理研究进展

原料天然气中二氧化碳(CO_(2))、羰基硫(COS)、硫化氢(H_(2)S)和甲硫醇(CH3SH)等酸性气体需要采用碱性溶剂予以脱除,在吸收过程中,以瞬时质子机理反应的H_(2)S脱除速率远远大于COS和CO_(2),故尽管原料气中COS含量通常远低于H_(2)S,但用于脱除H_(2)S的常规技术不能完全有效地脱除COS。COS与CO_(2)化学结构相似,但CO_(2)吸收速率远大于COS,因此,要深度脱除COS且保留部分CO_(2)难度较高。目前,对COS和CO_(2)吸收机理差异性的研究较少,导致在大量CO_(2)和COS共存的条件下,COS选择性吸收溶剂的设计缺乏理论依据。因此,需深入研究COS的吸收机理。对有机胺法吸收CO_(2)及COS的机理研究进展进行了总结,并提出以下认识:①在机理研究方面,普遍认为COS在伯胺和仲胺中的吸收机理与CO_(2)吸收机理相同;②醇胺吸收CO_(2)的机理通常认为是通过形成氨基甲酸盐而脱除CO_(2),进一步的加热分解即是CO_(2)的释放与吸收液的循环使用;③COS与CO_(2)均为线性分子,物理化学性质也非常接近,使得在二者共存的条件下,COS选择性吸收的难度较大。

介孔氧化硅分子筛负载金属氧化物高温煤气脱硫剂结构调控与脱硫过程放硫的研究进展

煤气化是煤炭清洁高效利用的核心技术,但气化粗煤气中所含硫化氢(H_(2)S)会腐蚀设备并污染环境,因此需要对煤气进行净化脱硫。介孔氧化硅分子筛具有大比表面积、大孔容和有序的介孔结构等特性,将其作为金属氧化物的载体可促进金属氧化物的分散,并为脱硫反应提供大量的反应活性位点,减少传质阻力。脱硫剂构效关系是煤气脱硫技术的关键科学难题之一,然而对于负载型高温煤气脱硫剂而言,上述关系受介孔氧化硅分子筛、脱硫活性组分种类、脱硫剂改性手段和脱硫条件等多因素叠加影响,因而要明晰其本质极具挑战。为此,首先探讨了不同介孔氧化硅分子筛的孔道结构特性,剖析了介孔氧化硅分子筛负载活性组分后的脱硫行为差异,发现拥有丰富孔结构及较厚孔壁的载体的脱硫剂在高温脱硫过程中表现更优。同时,分析了近年来针对锌基、锰基和铁基等金属氧化物负载型脱硫剂的结构调控策略及其对脱硫性能的影响规律,认为通过金属掺杂复合改性可提高活性组分脱硫活性;并对脱硫过程中的放硫机制、放硫规律及抑制手段进行了探讨,认为在脱硫剂中引入催化羰基硫(COS)氢解助剂可有效抑制放硫行为。本综述内容可为高性能高温脱硫剂结构设计与功能化构筑提供理论依据。

延迟焦化装置液化石油气降低总硫技术改造总结

中国石油化工股份有限公司镇海炼化分公司1号产品精制装置焦化液化石油气脱硫脱硫醇系统,通过使用脱羰基硫溶剂UDS、纤维膜换代、投用碱液再生系统,解决了精制焦化液化石油气羰基硫高、脱硫醇效果差、碱渣外排量高等问题,使得焦化液化石油气羰基硫脱除率达到90%以上,精制焦化液化石油气产品羰基硫的质量浓度由99 mg/m^(3)降至10 mg/m^(3)以内,远低于去气分装置回收丙烯的质量要求(质量浓度不大于60 mg/m^(3))。自投用运行以来,回收焦化液化石油气中丙烯,每年可增加经济效益约4063万元。为同类装置焦化液化石油气降低总硫工艺优化提供了参考借鉴。

谷物和油料中甲酸乙酯和硫化羰本底水平评估

甲酸乙酯和硫化羰是潜在的储藏物熏蒸剂,广泛存在于大气、植物和土壤中。它们在新收获的谷物和储存的小麦、大麦、燕麦和油菜籽中的本底含量因商品、温度、含水量和储存期而异,其中甲酸乙酯含量为0.5~2.0 mg/kg,硫化羰含量为0.02~1.0 mg/kg。两种成分含量在储存后的前4~5个月呈上升趋势,然后下降,在温度高于20℃,谷物和油菜籽含水量分别大于9.5%和5%时变化最明显。这些本底含量研究对开发甲酸乙酯和硫化羰作为储藏物熏蒸剂时制定最大残留限量(MRL)和市场接受度值有重要参考价值。

钢铁行业高炉煤气精脱硫技术应用现状和未来趋势研究

高炉炼铁处于长流程钢铁冶炼生产工艺中的关键环节,高炉煤气是炼铁过程副产的重要二次能源,通常在高炉热风炉、轧钢加热炉和自备电厂煤气发电等生产工序进行燃烧利用。高炉煤气精脱硫技术的工程应用作为钢铁行业进行源头减排的典型实施方案具有非常重要的意义,国家与地方相关部门对于高炉煤气脱硫技术的应用也明确提出了最新要求。结合高炉煤气组分复杂、工况波动的特征和硫组分形态不同、有机硫为主的含硫特点以及不同脱硫技术的主要特点,重点分析了针对煤气中硫化氢的脱除方法、羰基硫的脱除方法以及硫化氢和羰基硫的一体化脱除方法,并通过对近年来钢铁行业高炉煤气精脱硫技术的工程应用现状调研,进一步对高炉煤气精脱硫技术后续的研发方向和工程应用等方面提出了几点建议。