新型长寿命热煤气脱硫剂的研制

介绍了“九五”科技攻关项目“联合循环发电关键技术－高温煤气脱硫研制及脱硫再生工艺研究开发”专题中,关于研制新型长寿命脱硫的最新结果。经大量的配方设计及试验,成功筛选出G－201及G－202两种脱硫剂。其中G－201脱硫剂在工艺放大的试验装置上首次成功地通过1500h真实热煤气脱硫长寿命考核试验。经过检查,考核试验后的脱硫剂无粉化和烧结现象,并保持足够的机械强度、实测硫容仍保持21％,守好如初。     

Desulfurization performance of iron-manganese-based sorbent for hot coal gas

A series of iron-manganese-based sorbents were prepared by co-precipitation and physical mixing method, and used for H₂S removal from hot coal gas. The sulfidation tests were carried out in a fixed-bed reactor with space velocity of 2000 h⁻¹(STP). The results show that the suitable addition of manganese oxide in iron-based sorbent can decrease H₂S and COS concentration in exit before breakthrough due to its simultaneous reaction capability with H₂S and COS. Fe₃O₄ and MnO are the initial active components in iron-manganese-based sorbent, and FeO and Fe are active components formed by reduction during sulfidation. The crystal phases of iron affect obviously their desulfurization capacity. The reducibility of sorbent changes with the content of MnO in sorbent. S7F3M and S3F7M have bigger sulfur capacities (32.68 and 32.30 gS/100 g total active component), while S5F5M has smaller sulfur capacity (21.92 gS/100 g total active component). S7F3M sorbent has stable sulfidation performance in three sulfidation-regeneration cycles and no apparent structure degradation. The sulfidation performance of iron-manganese-based sorbent is also related with its specific surface area and pore volume.     

Preparation and selection of Fe-Cu sorbent for COS removal in syngas

A series of iron-based sorbents prepared with iron trioxide hydrate, cupric oxide by a novel method was studied in a fixed-bed reactor for COS removal from syngas at moderate temperature. In addition, the sorbents mixed with various additives in different ratios were tested. The effects of additive type and ratio on the breakthrough capacity and desulfurization performance, as well as the influence of operating conditions on sulfidation behavior of the sorbent, were investigated. The simulate gas contained 1% COS, 5% CO₂, 20%–30% CO and 60%–70% H₂. The outlet gases from the fixed-bed reactor were automatically analyzed by on-line mass spectrometry, and the COS concentration before breakthrough can be kept steady at 1 ppmv. The result shows that the breakthrough sulfur capacity of the sorbent is as high as 25 g-S/100 g. At 700 K and space velocity of 1000 h⁻¹, the efficiency of sulfur removal and breakthrough sulfur capacity of the sorbent increase with the increase of copper oxide with an optimum value. The result shows that the species and content of additives also affect desulfurization performance of the sorbent.     

高温煤气脱硫剂的研究

介绍了高温煤气脱硫剂的研制、脱硫工艺条件试验、再生工艺条件试验和长周期考核试验。结果表明,以锌、锰和铁等氧化物为主成分,辅加多种助剂的高温煤气脱硫剂,可在(350～600)℃脱除煤气中的H_2S和COS,脱硫精度高,硫容大,脱硫剂脱硫后可再生。脱硫剂经22次脱硫-再生循环操作后,仍具有高脱硫性能。     

热煤气一体化净化工艺中的脱硫反应特征

利用固定床反应器考察了高温煤气脱硫除尘一体化净化工艺中沉积粉尘对高温煤气脱硫剂脱硫性能的影响.结果表明,表面沉积粉尘对脱硫剂初次硫化行为有明显的影响,且与脱硫剂的组成和结构有关.利用钢厂赤泥制备的脱硫剂,含有多种惰性杂质,且具有较大的孔径结构,易于和粗煤气中的粉尘作用,造成脱硫剂硫容的减小.硫化气氛中,H2O的存在造成脱硫剂硫容和脱硫效率的降低,但不会影响因表面沉积粉尘造成的脱硫剂硫容的减小.多次硫化-再生循环实验表明,硫化-再生循环过程有助于减小表面沉积粉尘对脱硫剂脱硫行为的影响.经历一定次数的硫化-再生循环后,粉尘对脱硫剂脱硫行为的影响逐渐消失.     

Reactivity of copper oxide-based sorbent in coal gas desulfurization

Various CuO-based sorbents were prepared to investigate effects of sorbent ingredients such as SiO₂, MnO₂, and MoO₃ on desulfurization reactivity. Several candidate sorbents chosen from a TGA screening test were further tested in a microreactor system. The amount of SiO₂ support to minimize sintering of sorbents was 25 wt%. Sulfur loading was seriously affected by the amount of additives (MnO₂, MoO₃) in a multi-cycle test. Improvement of sulfur loading by the additives was observed in the multi-cycle test. Effects of support materials on sulfur loading were also investigated by using SiO₂, g-alumina and zeolite. SiO₂ showed the best performance among the support candidates. The sorbent showing the best sulfur loading ability was CMS6 (CuO :MoO₃ : MnO₂ : SiO₂=61 : 11 : 3 : 25). Its sulfur loading reached up to 13.8 g sulfur/100 g sorbent in a multi-cycle test.     

Modified Semi‐Coke‐Supported Cerium Oxide‐Doped Zinc Ferrites for the Removal of H2S from Coal Gas

Cerium oxide‐doped ZnFe₂O₄ sorbents supported on modified semi‐coke (MSC) were prepared to improve the desulfurization efficiency of zinc ferrites. The sulfidation tests of the ZnFe₂O₄/MSC sorbents with and without Ce were carried out using a fixed‐bed reactor at 450 °C. The effect of the CeO₂/ZnFe₂O₄ molar ratio of the sorbents on the sulfur capacity was studied. The characteristics of the sorbents were analyzed by X‐ray diffraction, N₂ adsorption, scanning electron microscopy and X‐ray photoelectron spectroscopy. The results showed that cerium oxide could greatly improve the desulfurization reactivity of the ZnFe₂O₄/MSC sorbents. The molar ratio of Ce to Zn and Fe influences the desulfurization reactivity, and a good sulfur capacity of the sorbent can be obtained with a Ce/Zn/Fe ratio of 4:4:1. It was also found that the addition of CeO₂ could enlarge the surface area and the pore volume, thus improving the dispersion of active components. Ce doping results in an increment of the oxygen adsorbed on the sorbent surface, which facilitates the adsorption of H₂S. The Ce ions could act as carriers of the oxidation and reduction reactions and the oxygen transfer could be accelerated during the desulfurization process of coal gas.     

锰系可再生高温脱硫剂的制备及其性能测试

煤气的高温脱硫净化是 IGCC 和 DRI 生产的瓶颈,直接影响整个过程的热效率。在50℃、pH值约为9的条件下采用硝酸锰、硝酸铝混合溶液与氨水进行共沉淀,制备了锰含量不同的脱硫剂,在固定床反应器中考察了脱硫剂的硫化及再生性能,并利用XRD、SEM、BET等手段表征了脱硫剂在硫化/再生过程中的物相和结构变化。共沉淀法制备的脱硫剂Mn/Al分散性好,在850℃高温下进行脱硫反应可以定量快速进行。脱硫硫容与脱硫剂锰含量呈正比,Mn-S/Mn-O交换原子比在0.90~0.95之间,改变空速和进口H₂S含量并不改变脱硫硫容。采用O₂浓度为3%的稀释空气在850℃下再生,再生后的硫容稳定,说明所制备的脱硫剂可用于高温可再生脱硫。     

Molecular hydrogen and spiltover hydrogen storage on high surface area carbon sorbents

A series of templated carbons with various high surface areas (2033–3798 m²/g) have been prepared using various microporous zeolites as hard templates. Molecular hydrogen storage and spiltover hydrogen storage on these templated carbons were investigated and compared with superactivated carbon AX-21 and other reported porous carbon sorbents at 298 K and 100 atm. Two relationships between the surface areas of these carbons and their hydrogen capacities were obtained. The relationship between molecular hydrogen capacity and surface area showed a 0.23 wt.% H₂/1000 m²/g of carbon sorbent at 298 K and 100 atm, indicating that merely increasing surface areas of the carbon sorbents cannot achieve a significant molecular hydrogen capacity at ambient temperature. Spiltover hydrogen storage was achieved by doping Pt nanoparticles (as dissociative hydrogen source) on these carbons (spiltover hydrogen receptor). Our first result on the relationship between the spiltover hydrogen capacity and surface area showed 0.4 wt.% H₂/1000 m²/g of carbon sorbent at 298 K and 100 atm, which indicated that storage via spillover can lead to an average of 70% enhancement compared to molecular hydrogen storage.     

Desulfurization of Transportation Fuels by Adsorption

This paper is a review on sorbents for desulfurization of transportation fuels (gasoline, diesel, and jet fuel). Since the π-complexation sorbents are the most promising, they are the focus of the discussion. During π-complexation, the thiophenic compounds can bind selectively to the sorbents, especially the substituted ones. The later remain highly unreacted in hydrodesulfurization (HDS) (i.e., “refractory” sulfur). Molecular orbital (MO) calculations and experiments have shown that these refractory compounds [(e.g., 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene (DMDBT)] bind strongly with the π-complexation sorbents because of a better electron donation/back-donation ability. The sorbents reviewed include Ag-Y, Cu(I)-Y, Ni(II)-Y, and Ni(II)-X zeolites prepared using various ion-exchange techniques. The techniques included vapor and solid-state ion exchanges, which are suitable for obtaining high loadings of transition metals. The best sorbent, Cu(I)-Y [vapor-phase ion-exchanged (VPIE)], is capable of producing almost 38 cm³ of desulfurized fuel per g of sorbent with a sulfur concentration of less than 0.2 ppmw. Using these π-complexation sorbents in layered bed matrices further increases the desulfurization capacity.     

Novel‐doped zinc oxide sorbents for low temperature regenerable desulfurization applications

Eight metal oxide sorbents including transition metal doped ZnO/SiO₂ sorbents and ZnO/SiO₂ were prepared by incipient wetness impregnation for regenerable desulfurization applications at low temperatures (i.e. room temperature). Among them, copper‐doped sorbent (Cu‐ZnO/SiO₂) demonstrated the highest saturation sulfur capacity of 0.213 g sulfur/g ZnO (54% of the theoretical capacity), which is twice that of ZnO/SiO₂ sorbent. Compared with ZnO/SiO₂, Cu‐ZnO/SiO₂ demonstrated superior desulfurization performance in a wide temperature range of 20–400°C. Due to the use of porous SiO₂ support, Cu‐ZnO/SiO₂ is highly regenerable. It can be easily regenerated in air at low temperatures, ca. 300–550°C, which are much lower than the typical regeneration temperatures of commercial ZnO sorbents. Cu‐ZnO/SiO₂ maintained its sulfur capacity during 10 cycles of regeneration/sulfidation. © 2010 American Institute of Chemical Engineers AIChE J, 2010     

Desulfurization of Transportation Fuels by Adsorption

Abstract

This paper is a review on sorbents for desulfurization of transportation fuels (gasoline, diesel, and jet fuel). Since the π‐complexation sorbents are the most promising, they are the focus of the discussion. During π‐complexation, the thiophenic compounds can bind selectively to the sorbents, especially the substituted ones. The later remain highly unreacted in hydrodesulfurization (HDS) (i.e., “refractory” sulfur). Molecular orbital (MO) calculations and experiments have shown that these refractory compounds [(e.g., 4‐methyldibenzothiophene and 4,6‐dimethyldibenzothiophene (DMDBT)] bind strongly with the π‐complexation sorbents because of a better electron donation/back‐donation ability. The sorbents reviewed include Ag‐Y, Cu(I)‐Y, Ni(II)‐Y, and Ni(II)‐X zeolites prepared using various ion‐exchange techniques. The techniques included vapor and solid‐state ion exchanges, which are suitable for obtaining high loadings of transition metals. The best sorbent, Cu(I)‐Y [vapor‐phase ion‐exchanged (VPIE)], is capable of producing almost 38 cm³ of desulfurized fuel per g of sorbent with a sulfur concentration of less than 0.2 ppmw. Using these π‐complexation sorbents in layered bed matrices further increases the desulfurization capacity.     

微波固相法制备铁酸锌脱硫剂的硫化动力学

通过微波与常规固相法制备了铁酸锌高温煤气脱硫剂,使用X射线衍射（XRD）、氮吸附、扫描电子显微镜（SEM）以及X射线光电子能谱（XPS）对两种不同焙烧方式制备的脱硫剂的物相组成、织构形貌和表面元素进行了表征。数据显示微波焙烧制备的脱硫剂具有孔隙结构丰富、表面金属元素含量高、结合能低等优点。使用热天平对铁酸锌脱硫剂硫化行为进行了研究,根据等效粒子模型计算了两种脱硫剂与硫化氢气体反应的动力学参数,得到了硫化反应动力学方程,并在固定床上对其煤气脱硫性能进行了考察。结果表明硫化过程分为化学反应控制区和颗粒内扩散控制区。微波焙烧制备脱硫剂的化学反应活化能和颗粒内扩散活化能较低,说明其在硫化氢气体脱除上具有更高的活性。在模拟煤气气氛下,相比常规焙烧方法制备的脱硫剂,微波制备的脱硫剂的脱硫性能显著提高,具有更高的硫容和更长的精脱硫时间。     

Sulfidation and regeneration of iron-based sorbents supported on activated-chars prepared by pressurized impregnation for coke oven gas desulfurization

The sulfidation and regeneration properties of lignite char-supported iron-based sorbent for coke oven gas (COG) desulfurization prepared by mechanical stirring (MS), ultrasonic assisted impregnation (UAI), and high pressure impregnation (HPI) were investigated in a fixed-bed reactor. During desulfurization, the effects of process parameters on sulfidation properties were studied systematically. The physical and chemical properties of the sorbents were analyzed by X-ray diffraction (XRD), scanning electron microscope coupled with energy dispersive spectroscopy (SEM-EDS), Fourier transform infrared (FTIR) and BET surface area analysis. The results of desulfurization experiments showed that high pressure impregnation (HPI) enhanced the sulfidation properties of the sorbents at the breakthrough time for char-supported iron sorbents. HPI method also increased the surface area and pore volume of sorbents. Sulfur capacity of sorbents was enhanced with increasing sulfidation temperatures and reached its maximum value at 400 °C. It was observed that the presence of steam in coke oven gas can inhibit the desulfurization performance of sorbent. SO₂ regeneration of sorbent resulted in formation of elemental sulfur. HPIF10 sorbent showed good stability during sulfide-regeneration cycles without changing its performance significantly.     

Desulfurization of high-sulfur jet fuel by mesoporous π-complexation adsorbents

Desulfurization of JP-5 jet fuel (1172 ppmw S) was investigated by π-complexation adsorption with AgNO₃ supported on mesoporous silica SBA-15 and MCM-41. The average pore sizes of AgNO₃/SBA-15 and AgNO₃/MCM-41 were 48.8 and 19.1 Å, respectively. The results of JP-5 desulfurization showed that significant sulfur breakthrough occurred at ∼10.0 and ∼15.0 mL/g by AgNO₃/SBA-15 and AgNO₃/MCM-41, respectively, at a space velocity of 1.25 h⁻¹. The spent AgNO₃/MCM-41 was regenerated by a simple process (heating in air at 200 °C) and ∼50% of the sulfur capacity was recovered after the first cycle. Molecular orbital calculations show that Cu⁺ (as that in CuY zeolite) formed stronger π-complexation bonding with the thiophenic compounds than Ag⁺ (in AgNO₃), as evidenced by experimental heats of adsorption. However, pore diffusion limitation of the large sulfur molecules (alkylated benzothiophenes) became an important factor for desulfurization of high sulfur jet fuels such that the AgNO₃-supported mesoporous sorbents yielded substantially better results than Cu(I)Y, although Cu(I)Y was better for a model fuel that contained only small sulfur molecules. Among all sorbents that have been investigated, the AgNO₃/MCM-41 sorbent showed the best desulfurization performance for high sulfur jet fuels.     

Desulfurization matching with coal poly-generation system based on dual gas resources

The coal poly-generation system for the production of alcohol and ether fuels as well as power is one of advanced coal utilization techniques. The team leaded by Professor Xie Kechang is carrying out the research on the poly-generation system to produce the syngas from the combination of gasified and pyrolyzed coal gas (dual gas resources) for the alcohol ether synthesis. Gas desulfurization is one of the key technologies for this system. The desulfurization matching with dual gas resources based poly-generation system for the production of alcohol and ether fuels as well as power is presented according to gas components, sulfur content, sulfur species and desulfurization accuracy in this technology. This matching desulfurization is classified into hot gas desulfurization, normal gas desulfurization, warm gas desulfurization and organic sulfur catalytic conversion. The preparation of H₂S removal sorbents, organic sulfur hydrolysis catalyst and the evaluation of their activities involved in the system were investigated. The H₂S removal efficiencies of the crude and fine desulfurization sorbents prepared for hot gas desulfurization are 90% and 99% at 500 °C in simulating coal gas, and their sulfur capacities are 21.85 wt.% and 24.91 wt.%, respectively. The organic sulfur catalyst shows the high hydrolysis activity, and the hydrolysis conversion of COS is more than that of CS₂ on the same catalyst. The research will provide necessary information for the matching desulfurization technology in the demonstration project on dual gas resources coal poly-generation system.     

A study of desulfurization ability and activation energy for CuO-AgO sorbents

In this study, we investigated desulfurization abilities and activation energy using TGA for CuO-AgO sorbents calcined at 700 °C. CuO was used as a main active material and AgO was used as an additive material and 25 wt% SiO₂ was used as a support material. The desulfurization reaction temperatures were 450 °C, 500 °C, and 550 °C and the regeneration reaction temperature was 700 °C. From the TGA experiments, the best sulfur loading of CAS1 sorbent containing 1 wt% AgO was about 14.95 g sulfur/100 g sorbent at 550 °C. The activation energy was calculated by the Chatterjee-Conrad method based on the TGA experiment. Desulfurization ability and activation energy of sorbent were decreased as the content of AgO increased.     

助剂对复合金属脱硫剂物化性能的影响

为了获得更加高效的脱硫剂，仵实验室固定床脱硫装置上进行脱硫试验，在操作温度700K，空速为1000h^-1时的条件下，以氧化铁现氧化铜为丰要活性组分，考察了添加助剂对脱硫剂物理与化学性能的影响。结果表明：添加助剂K的脱硫荆的强度为81．7N／cm，堆积密度为0．717g／cm^3，出口羰基硫浓度比添加其他两类助剂低，并长时间保持低于0．2×10^-1，硫容达24．3g·S／100g。     

Preparation and application of zeolite beta with super-low SiO<Subscript>2</Subscript>/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> ratio

This paper presents the direct synthesis of super-low SiO₂/Al₂O₃ ratio zeolite beta molecular sieve through a novel route, by which some of aluminium species are added during crystaling process. The IR results show that with the increase of aluminium content in the framework, the frequency of the band in the range of framework vibration (1060–1090 cm⁻¹) shifts to the lower wave-number; the BET surface-area decreases and the basicity of zeolite becomes stronger. In a second step, new adsorbents were obtained by solid-state ion exchanging zeolite beta with Cu(I), Ag(I) cations. The deep-desulfurization (sulfur levels of <1 ppmw) tests were performed using fixed-bed adsorption technique, the sulfur content of the treated and untreated gasoline was analyzed by microcoulometry. The experimental results show that the desulfurization performance of sorbents decreases in order: Cu(I)beta > Ag(I)beta > Na-beta. The best sorbent, Cu(I)beta, has breakthrough adsorption capacities of 0.236 mmolS/g of sorbent for model gasoline.     

Supported silver adsorbents for selective removal of sulfur species from hydrocarbon fuels

Dispersed silver oxides on supports such as TiO₂, γ-Al₂O₃ and SiO₂ were observed to be effective desulfurizing agents for refined fuels at ambient conditions. TiO₂ was determined to be the most stable support for silver oxide. Ag (4 wt%)/TiO₂ demonstrated a saturation sulfur capacity of 6.3 mgS/g for JP5 fuel containing 1172 ppmw sulfur. This high affinity for sulfur translated to one sulfur heterocycle associated with every two surface Ag atoms in the sorbent even in the presence of a 160-fold excess of other aromatics found in the fuel. A unique attribute of these sorbents was that they were thermally regenerable at 450 °C using air as a stripping medium over multiple cycles. Desulfurization characteristics also varied with fuel composition. Variation in desulfurization performance between JP5, JP8 and a light fraction JP5 were established and associated with the differences in sulfur composition of these fuels. The effects of surface area, porosity and crystal structure of the sorbent on sulfur capacity are also presented.