Synergistic catalysis of the N-hydroxyphthalimide on flower-like bimetallic metal-organic frameworks for boosting oxidative desulfurization

Synergic catalytic effect between active sites and supports greatly determines the catalytic activity for the aerobic oxidative desulfurization of fuel oils.In this work,Ni-doped Co-based bimetallic metal-organic framework(CoNi-MOF)is fabricated to disperse N-hydroxyphthalimide(NHPI),in which the whole catalyst provides plentiful synergic catalytic effect to improve the performance of oxidative desulfurization(ODS).As a bimetallic MOF,the second metal Ni doping results in the flower-like morphology and the modification of electronic properties,which ensure the exposure of NHPI and strengthen the synergistic effect of the overall catalyst.Compared with the monometallic Co-MOF and naked NHPI,the NHPI@CoNi-MOF triggers the efficient activation of molecular oxygen and improves the ODS performance without an initiator.The sulfur removal of dibenzothiophene-based model oil reaches 96.4%over the NHPI@CoNi-MOF catalyst in 8 h of reaction.Furthermore,the catalytic product of this aerobic ODS reaction is sulfone,which is adsorbed on the catalyst surface due to the difference in polarity.This work provides new insight and strategy for the design of a strong synergic catalytic effect between NHPI and bimetallic supports toward high-activity aerobic ODS materials.

Mathematical simulation of hot metal desulfurization during KR process coupled with an unreacted core model

A three-dimensional mathematical model was established to predict the multiphase flow,motion and dispersion of desulfurizer particles,and desulfurization of hot metal during the Kanbara reactor(KR)process.The turbulent kinetic energy-turbulent dissipation rate(k-ε)turbulence model,volume-of-fluid multiphase model,discrete-phase model,and unreacted core model for the reaction between the hot metal and particles were coupled.The measured sulfur content of the hot metal with time during the actual KR process was employed to validate the current mathematical model.The distance from the lowest point of the liquid level to the bottom of the ladle decreased from 3170 to2191 mm when the rotation speed increased from 30 to 110 r/min,which had a great effect on the dispersion of desulfurizer particles.The critical rotation speed for the vortex to reach the upper edge of the stirring impeller was 70 r/min when the immersion depth was 1500 mm.The desulfurization rate increased with the increase in the impeller rotation speed,whereas the influence of the immersion depth was relatively small.Formulas for different rotation parameters on the desulfurization rate constant and turbulent energy dissipation rate were proposed to evaluate the variation in sulfur content over time.

Process design for gas condensate desulfurization and synthesis of nano-13X zeolite adsorbent: equilibrium and dynamic studies

This paper summarizes the results of a study of adsorption of sulfur compounds from a high-sulfur feed on improved spherical-shaped nano-AgX zeolite. For this purpose, the nano-AgX zeolite was initially synthesized and improved with silver compounds such as silver nitrate, and then it was utilized in the adsorption process. In order to investigate the equilibrium and dynamics of the adsorption process, adsorptive desulfurization of real feed(i.e., sour gas condensate from the South Pars gas field) was carried out in batch and continuous processes under several operating conditions; a temperature-dependent Langmuir isotherm model was used to fit the equilibrium data. The value of monolayer adsorption capacity(q_m) and adsorption enthalpy(ΔH) were calculated to be 1.044 mmol/g and 16.8 kJ/mol, respectively. Furthermore, a detailed theoretical model was employed in order to model the breakthrough experiments. The results revealed that an increase in the feed flow rate and 1/T values will cause linear and exponential increase in the total mass transfer coefficient(ks). Isotherm and dynamic breakthrough models were found to be in agreement with the experimental data.

Wet flue gas desulfurization performance of 330 MW coal-fired power unit based on computational fluid dynamics region identification of flow pattern and transfer process

Wet Flue Gas Desulfurization(WFGD)unit based upon spray scrubber has beenwidely employed to control SO_(2) emissions from flue gas in coal-fired power plant.To clarify the dependence of desulfurization performance on inter-phase transfer behaviors with non-ideal contacting patterns of flue gas and slurry droplets,three regions in spray scrubber are distinguished in terms of gas-slurry flow structures using CFD method in the Eulerian-Lagrangian framework.A comprehensive model is established by involving the transfer process between two phases and chemical reactions in aqueous phase,which is validatedwith the measured data froma WFGD scrubber of 330 MW coal-fired power unit.Numerical results show that the overall uniformity degree of flue gas in whole scrubber is largely determined by the force-balanced droplets in the middle part of scrubber,which is dominated by counter-current mode.Both momentum transfer behavior and SO_(2) chemical absorption process present the synchronicity with the evolution of gas-slurry flow pattern,whilst the heat transfer together with H_(2)O evaporation has little effect on overall absorption process.Three regions are firstly defined as Gas Inlet Region(GIR),Dominant Absorption Region(DAR)and Slurry Dispersed Region(SDR)from the bottom to top of scrubber.SO_(2) is mainly scrubbed in DAR,which provides much more intensive interaction between two phases compared to GIR or SDR.A better understanding of the desulfurization process is obtained from the fundamental relationship between transport phenomena and chemical reactions based upon the complicated hydrodynamics of gas-slurry two-phase flow,which should be useful for designing and optimizing the scrubber in coal-fired power unit.

AN ADVANCED COAL DESULFURIZATION PROCESS──SELECTIVE FLOCCULATION

Selective flocculation is an idea separation method to separate ultrafine pyrite from coal. A number of selective flocculation separation tests under different conditions have been done and the results are very encouraging. The results also show that desulfurization and deashing can be finished simultaneously in selective fIocculation process. It is an advanced coal desulfurization process.

Feasibility of an innovative integrated process of simultaneous desulfurization and denitrification for high strength wastewater

An anaerobic expanding-bed reactor was adopted to investigate the feasibility of an innovative integrated process of simultaneous desulfurization and denitrification （SDD） for high strength wastewater. In the reactor, heterotrophic bacteria （including sulfate reducing bacterium and denitrifying bacteria） and autotrophic bacteria （ including Thiobacillus denitrificans） cooperated together by incubating and enriching functional bac- teria on different carriers in the anaerobic activated sludge. Synthetic wastewater with high concentrations of sulfate and nitrate was employed. The experimental resuhs showed that the removal efficiency of sulfate and nitrate was above 85% , elemental sulfur was observed while nitrate was absent in effluent. The balance of sulfur, nitrogen and electron was discussed respectively, which indicated that the integrated SDD process could be actualized. These resuhs might provide a guidance to further investigate the key factors affecting the integrated SDD process and to improve the efficiency of desulfurization and denitrification in wastewater treatment.

DEVELOPMENT OF SMOVEN PROCESS FOR HOT GAS DESULFURIZATION

The Beijing Research lnstitute of Coal Chemistry (BRICC) is developing the SMOVEN process for hot gas desulfurization. The SMOVEN process features sulfidation in an entrained bed,regeneration in a low velocity fluid bed or a moving bed with oxygen and sorbent circuIation con-trolled by gas stream. A series of tests on the bench scale unit and the continuous process devel-opment unit were carried out. The regenerable metal oxide sorbents were adopted for the sulfur-related components removing from coal gas at the temperature of 550-650℃. A fluidized bed gasifier of 100 mm (id) generated coal gas for tests. The principle of SMOVEN process has been positively verified.

Measuring particle size distribution and total number in the activation chamber of desulfurization system by PIV

Application of particle image velocity (PIV) techniques for measuringparticle size distribution and total number in an activation chamber of desulfurization system isintroduced. Watersheld algorithm is used to choose the suitable initial gray level threshold whichis used to change the gray level images taken by PIV to black and white ones, then every particle inan image is isolated totally. For every isolating particle, its contour is tracked by the edgeenhancement filter function and kept by Freeman s chain code. Based on a set of particle s chincode, its size and size distribution are calculated and sorted. Finally, the experimental data ofcalcium particles and water drops, separately injected into the activation chamber, and the erroranalysis of data are given out.

Feasibility of flue-gas desulfurization by manganese oxides

For the purpose of effective and economic desulfurization of flue-gas, the predominance area diagram of the Mn-S-O system at different temperatures was constructed based on the thermodynamic data obtained from the literatures. It is seen from this figure that flue-gas desulfurization by manganese oxides is feasible from the thermodynamic point of view. Additionally, the most appropriate temperature range for flue-gas desulfurization is between 600 and 800 K, and the reaction is strongly exothermic to maintain the heat balance. The natural manganese ores encompass large tunnels that exhibit large surface areas and highly chemical activity, which can provide a high enough SO2 removing efficiency. From the superposition of the diagrams of Mn-S-O and Fe-S-O systems, it is found that there is a coexistent stability region of MnSO4 and Fe2O3, which provides the possibility of desulfurization by selective sulfation without ferric sulfate forming. A multi-stage desulfurization system has been discussed briefly.

Leaching calcium from phosphogypsum desulfurization slag by using ammonium chloride solution: Thermodynamics and kinetics study

Phosphogypsum(PG) desulfurization slag is a calcium-rich residue from reductive decomposition of PG using sulfur as the reductant. We proposed a technology of preparation light calcium carbonate with PG desulfurization slag, which mainly contains two steps: leaching and carbonizing. In this work, we concentrated on the former, in which ammonium chloride aqueous solution was utilized as leaching agent to extract calcium from the slag, and conducted thermodynamics and kinetics study on it. Fact Sage software was employed to do thermodynamic and phase equilibrium diagram calculations. The influence of leaching conditions including agitation speed, initial concentration of leaching solution, reaction temperature, and liquid/solid ratio on the calcium leaching rate was discussed in detail by means of experiment optimal design. A kinetic model developed from the shrinking core model was given to describe the leaching process. The apparent kinetic activation energy(Ea) of the leaching reaction was calculated to be 10.58 kJ·mol^-1.

Trail of sulfur during the desulfurization via reactive adsorption on Ni/ZnO

The reactive adsorption behavior of thiophene on the reduced Ni/ZnO sample was investigated by a combination of theoretical and experimental study.It is widely accepted that Ni is responsible for the sulfur-removal of thiophene to release S-free hydrocarbons.Such surface reaction was simulated by DFT method.It is demonstrated that thiophene is mainly adsorbed as p-complexation mode over metallic Ni.During desulfurization,the Se Ni bond is formed and the Ce S bond is thus split without pre-hydrogenation,resulting in the formation of Ni_(3)S_(2)phase and S-free C4 olefin which can be further saturated in the presence of H_(2).The S-transfer between Ni_(3)S_(2)and ZnO was monitored by in-situ XRD and STEM with EDS mapping.Two essential features were identified for efficient S-transfer,namely,1)the H_(2)atmosphere,and 2)the two phases are presented with close contact.Based on the acquired information,a general scenario of sulfur trail has been proposed for the desulfurization of thiophene on Ni/ZnO.

脱硫石膏制备α-半水石膏研究进展及应用

随着中国工业的不断发展,产生了大量的脱硫石膏,目前脱硫石膏的综合利用量虽在逐年增加,但其利用率却在降低,探寻脱硫石膏的高值化利用途径迫在眉睫,其中脱硫石膏资源化利用途径之一是将其脱水转化成α-半水石膏。利用脱硫石膏来制备高性能、高附加值的α-半水石膏,不仅能减轻石膏堆积对环境的污染,减少天然石膏的开采,还能带来新的经济效益。基于此,系统地综述了国内外脱硫石膏制备α-半水石膏的研究现状及影响因素,总结了其生产工艺路径及应用,并对推进脱硫石膏的减量化、资源化利用提出了展望,旨在提高固废利用率,促进“碳中和、碳减排”。

采用自主研发的在线前处理系统同时分析脱硫废水中阴阳离子

电厂专用的全自动脱硫废水分析仪可以实现对超高浓度脱硫废水的自动化前处理以及分析,样品通过自动二步稀释,并与双系统离子色谱仪联用,对脱硫废水中的阴、阳离子同时进行检测。脱硫废水中阳离子主要有Na+、NH4+、K+、Mg2+、Ca2+,阴离子主要有F-、Cl-、NO3-、SO42-。本研究对仪器相关参数进行了验证,测试结果为,4种阴离子和5种阳离子的混合标准溶液在其线性关系内相关系数均大于0.999;4种阴离子的峰高和峰面积重复性RSD小于2.29%,5种阳离子的峰高和峰面积重复性RSD小于1.78%,实际样品中4种加标阴离子回收率在93.5%~100.2%之间;5种阳离子加标回收率在95.4%~103.8%之间。结果证明,该系统大大提高了分析效率,节省了人工成本,填补了市场空白。

双螺杆挤出机胶粉脱硫工艺条件的研究

研究同向双螺杆挤出机的螺杆结构、脱硫温度和螺杆转速对胶粉脱硫的影响。结果表明:螺杆结构越有利于提高螺杆的混合和剪切能力,胶粉的溶胶含量越大,交联密度越小;当脱硫温度从170℃升高至190℃时,胶粉的脱硫效果有一定改善;当螺杆转速从50 r·min^(-1)增至90 r·min^(-1)时,胶粉的脱硫效果明显改善;当脱硫温度为180~190℃、螺杆转速为50~70 r·min^(-1)时,中等混合和剪切能力螺杆脱硫的胶粉的脱硫效果较好,脱硫胶粉胶料的拉伸性能较优。

高硫铝土矿脱硫方法研究进展

高品质铝土矿在我国属于紧缺性矿产资源,我国有大量高硫铝土矿资源,但高硫铝土矿冶炼会降低Al_(2)O_(3)溶出率、降低赤泥沉降性能、污染氢氧化铝产品、腐蚀生产设备等,因此高硫铝土矿脱硫技术成为实现其高效综合利用、缓解铝土矿资源短缺的关键。目前高硫铝土矿脱硫技术主要分为预处理脱硫和溶出过程脱硫。预处理脱硫包括浮选法、焙烧法、电化学脱硫、微生物脱硫等。浮选法适合于含硫较低的铝矿石资源,对于低品位、高硫含量的铝矿石则存在浮选药剂用量大、废水排放量大等问题;焙烧法脱硫效率高,但传统堆积焙烧存在焙烧时间长、能耗高等问题;电化学脱硫具有低温、常压、高脱硫率、无二次污染等优点,但存在能耗高、生产规模受限制等问题;微生物脱硫生产成本和能耗较低、环保性较高,但特定菌种对生长环境要求苛刻,培育菌种周期长。溶出过程脱硫包括氧化蒸发法脱硫、沉淀法脱硫和石灰法脱硫等。氧化蒸发法能够清除铝酸钠溶液中大部分S^(2-),但对其他形态硫氧化效果不明显;沉淀法脱硫操作较为简单,但存在脱硫剂成本高,难以应用于实际生产的问题;石灰法只能脱除溶液中SO_(4)^(2-),对其他类型硫离子并未产生显著去除作用。未来,建议从以下几个方向着手解决高硫铝土矿脱硫问题:开发低温高效、低能耗焙烧工艺;改善或者研发新型脱硫捕收剂;筛选高效、易培育菌种,研究混合菌脱硫效果。

基于正交试验的天然气脱硫工艺多目标优化

目的针对天然气净化厂处理含硫天然气时常出现能耗较高、净化气流量较低、脱硫选择性较差等问题,基于Aspen HYSYS流程模拟软件,搭建含硫天然气净化厂脱硫单元稳态模拟模型。方法采用多目标正交试验法与综合频率分析法相结合的方法,以工艺总能耗、净化气流量和选择因子3个指标作为综合评判指标,对脱硫单元的吸收塔塔板数、吸收塔压力、胺液循环量和胺液进料温度4个关键工艺参数进行了优化,确定了脱硫单元工艺参数的最优组合方案,并对优化前后脱硫单元的综合性能进行了对比分析。结果①所搭建的稳态模拟模型能够准确地模拟脱硫单元的运行特性,满足工程应用的要求;②各因素对工艺总能耗的影响从大到小依次为:胺液循环量、吸收塔塔板数、吸收塔压力和胺液进料温度;各因素对净化气流量和选择因子的影响从大到小的顺序一致,均为吸收塔塔板数、吸收塔压力、胺液循环量和胺液进料温度;③脱硫单元关键工艺参数的最优组合为:吸收塔塔板数12块、吸收塔压力5.5 MPa、胺液循环量75 t/h、胺液进料温度28℃;④相较于优化前,优化后的工艺总能耗由11316.54 kW降至9590.61 kW,降幅为15.25%;净化气流量由4164.53 kmol/h增至4175.54 kmol/h,增幅为0.26%;选择因子由1.32增至2.20,增幅为66.67%。结论经过工艺参数优化后,脱硫单元的能耗显著降低,净化气流量得到一定的提升,脱硫选择性得到明显改善。

络合铁脱硫(CTS)工艺运行问题分析及改进措施

介绍了中国石油四川石化有限责任公司硫磺回收装置尾气提标单元应用的络合铁脱硫(CTS)工艺技术;阐述了工艺运行过程中出现的影响装置长周期安全环保运行的各项问题的改进措施,包括使用高效脱硫溶剂、CTS反应器升级改造、更换CTS单元循环溶液助剂、过滤机滤布优化调整和含硫尾气技术改造等。通过上述各项改进措施的实施,进入反应器的H 2S浓度显著降低,反应器积硫粉突破的次数明显减少,循环溶液的各项质量明显提升,过滤机硫粉滤出量较改造前增加3倍,外排烟气实现长期超低达标排放。上述改进措施实施后较为彻底地解决了CTS单元各项运行问题,装置运行关键参数稳定,总硫收率提高,保证了硫磺回收装置安全环保长周期运行,可作为同类装置技术改造的参考。

基于时延补偿的燃煤机组二氧化硫排放浓度抗干扰控制

针对1000 MW燃煤机组脱硫过程能耗高及定值控制实现难的问题,进行了二氧化硫出口浓度闭环控制方法研究。首先,基于开环辨识建立了不同典型负荷点脱硫塔内调控泵频率与出口二氧化硫浓度之间的面向控制器设计的传递函数动态模型。其次,采用了结合史密斯预估器和扰动与不确定性估计技术(UDE)的闭环控制方案,在补偿脱硫过程大范围时延的同时增强闭环系统对模型不确定性和外部干扰的抑制能力。最后基于充分的鲁棒性评估确定了控制策略的参数。仿真和现场应用结果表明,论文研究的控制方法能够实现燃煤机组出口二氧化硫浓度的定值控制,并具备较为出色的瞬态响应性能。

反应吸附脱硫催化剂的研究进展

现行轻型汽车污染物排放限值及测量方法(中国第六阶段)(GB 18352.6—2016)要求汽油中的硫质量分数不能超过10μg/g,因此汽油的深度脱硫技术将持续受到关注。反应吸附脱硫技术具有脱硫率高、辛烷值损失低的优点,是目前用于汽油脱硫的主要手段之一。了解和认识反应吸附脱硫催化剂的组成和各组分之间的相互作用机理,对于提高催化剂活性和稳定性,推进反应吸附脱硫技术发展具有重要意义。详细介绍了反应吸附脱硫催化剂中脱硫活性金属组分、储硫组分、以及载体3种组分的功能与研究进展,分析了每种组分优化对脱硫催化剂活性的影响,讨论了反应吸附脱硫过程中的机理问题,以期为未来反应吸附脱硫催化剂的研发提供参考。

硫化物对厌氧氨氧化耦合自养脱硫反硝化工艺脱氮除硫效能的影响

以成熟Anammox颗粒污泥与产甲烷颗粒污泥作为接种物实现了硫自养反硝化耦合厌氧氨氧化(SADA)工艺快速启动,探究了不同硫化物负荷对SADA工艺脱氮效能的影响及其脱硫机理.结果表明:较高硫化物负荷(>1.50g S/(L·d))对耦合系统中An AOB无显著抑制作用,相应的系统脱氮效率连续运行1.5个月后趋于稳定.当将硫化物浓度降为零,耦合系统的总氮去除率(TNRE)仍能达到88.1%,相应的化学计量比R_(s)(1.23±0.13)与R_(p)(0.33±0.08)亦与Anammox理论值近似,表明解除高硫化物负荷胁迫条件后SADA系统中Anammox颗粒污泥仍能实现生物脱氮过程.当解除高硫化物负荷胁迫1.5个月后,在较低硫化物负荷条件下(0.30g S/(L·d))恢复硫化物胁迫,耦合系统出水NO_(3)^(-)降低,相应的R_(p)降至0.21,表明SADA系统仍能较好地实现同步脱氮除硫,兼具硫自养反硝化和厌氧氨氧化的双重功效.系统存在的产甲烷颗粒污泥降低硫化物对An AOB抑制,缩短了SADA工艺启动时间,且能在重新引入硫化物后快速激活脱硫反硝化过程.通过颗粒污泥形态分析和高通量测序菌群解析可知:不同硫化物胁迫条件下,SADA系统中仍能实现An AOB(如Candidatus Kuenenia,16.9%)和硫氧化菌(如Thiobacillus,31.6%)的共存富集,且能实现高硫化物负荷条件下较高的TNRE(>60%)和硫单质产率(95.2%).