焙烧温度对高温Mn-Fe-Ca脱硫剂脱硫性能的影响

采用机械混合法制备了Mn-Fe-Ca脱硫剂,通过XRD,SEM和H2-TPR等手段研究了焙烧温度对脱硫剂的织构、物相和还原性能的影响,并在固定床反应器中考察了焙烧温度对脱硫剂脱硫性能的影响.结果表明,1 050 ℃下焙烧后的脱硫剂有较好的机械强度和脱硫性能,脱硫精度最高可达4×10-6,硫容量可达33.3%.焙烧温度的改变,可以改变脱硫剂的微观结构和反应活性.     

高温煤气脱硫剂的研制及活性评价

采用钢厂的废物赤泥为活性成分,添加不同的黏结剂及造孔剂制备出了高温煤气脱硫剂。对制备的脱硫剂的脱硫活性和机械强度进行了测试与表征。结果表明,以赤泥为原料制备的脱硫剂是一种性能优良的脱硫剂。黏结剂的添加不仅能够提高脱硫剂的抗粉化性能,而且也可通过改变脱硫剂的织构来影响脱硫效果,分别添加三种黏结剂后,脱硫剂的机械强度最高的由188 N/cm提高到230 N/cm。同时通过对脱硫剂的硫容和穿透曲线进行的综合考察,发现高机械强度的脱硫剂,并不一定有高的硫容和脱硫效率,而适宜的强度能够提高脱硫剂的脱硫效率。     

负载型氧化锌脱硫剂脱硫性能的改善

单一氧化锌负载型脱硫剂脱硫精度可达到0.1×10-6,但其硫容量相对较低.采用共浸渍法制备ZnO-MnO2/γ-Al2O3负载型H2S脱硫剂,通过XRD和BET等手段研究了MnO2对脱硫剂物相及比表面积的影响.并在固定床反应器中考察了Zn/Mn摩尔比、负载量、烧结温度和脱硫温度对脱硫性能的影响.结果表明,活性组分锌锰摩尔比为8∶1,负载量为20％的脱硫剂有较好的脱硫性能,脱硫精度小于0.1×10-6的同时,最高硫容量可达19.08 g S/100 g(ZnO-MnO2).MnO2的加入可以明显改善氧化锌负载型脱硫剂的脱硫性能.     

新型Mn基高温脱硫剂研究

以铝溶胶为黏结剂用机械混合法研究了烧结温度、还原时间、黏结剂含量及空速对Mn-Cu脱硫剂效果的影响,结果表明,900℃为该脱硫剂的最佳烧结温度,脱硫前用N2和H2的混合气体还原0.5 h有利于脱硫反应的进行.加入适当含量的铝溶胶有利于延长穿透时间,提高脱硫精度.空速对不同铝溶胶含量的脱硫剂影响不同,但总体来看降低空速有利于延长穿透时间.     

氧化铈脱硫剂的高温煤气脱硫研究

用混合法制备CeO2脱硫剂,在固定床反应器中考察黏结剂、脱硫温度、还原时间对脱硫性能的影响.结果表明,预还原后的脱硫剂脱硫的初始阶段主要发生价态较低的氧化铈脱硫反应,随后氧化铈的价态受控于气氛的氧势,并表现出由不同价态氧化铈的脱硫效果.膨润土作为黏结剂要比高铝矾土有更好的脱硫性能.经预还原的氧化铈脱硫剂在900 C下可以在较高脱硫精度的情况下保持相当长的时间.     

铝基铜干法烟气脱硫剂制备及脱硫再生实验

采用浸渍法制备了铝基铜脱硫剂,考察了制备过程中浸渍液浓度对脱硫剂脱硫性能的影响,同时对制得的脱硫剂进行了循环烟气脱硫-再生实验,分析了脱硫剂的表面微观结构在脱硫和再生过程中的变化.实验和分析表明,制得的铝基铜脱硫剂具有较高的脱硫效率,使用该脱硫剂进行循环烟气脱硫的性能是稳定的.     

转化吸收型氧化锌基脱硫剂脱除H2S和COS性能

以前驱物工业活性ZnO和碱式碳酸锌分解的ZnO为脱硫剂活性组分,在引入结构助剂γ-Al_2O_3、碱性助剂K2CO3改性的基础上,制备出转化吸收型氧化锌基脱硫剂。在300℃、空速2000h–1及常压下,考察了活性组分ZnO前驱物种类及不同前驱物制备的助剂γ-Al_2O_3对氧化锌基脱硫剂脱除硫化物性能的影响。结果表明:改性氧化锌基脱硫剂的孔隙结构和碱性显著影响其脱硫性能。与工业活性ZnO制备的氧化锌脱硫剂相比,以碱式碳酸锌分解的ZnO制备的脱硫剂对硫化氢的脱除效率和穿透硫容更高,穿透硫容约增加10倍。不同前驱物制备的γ-Al_2O_3对氧化锌基脱硫剂脱硫性能有较大影响。其中,拟薄水铝石分解的γ-Al_2O_3显著提高了氧化锌基脱硫剂脱硫性能,穿透硫容达12.18%。以碱式碳酸锌分解ZnO为活性组分,添加拟薄水铝石分解的γ-Al_2O_3和碱性助剂K2CO3制备的改性氧化锌基脱硫剂对COS的脱除起到转化与吸收作用,COS转化率达99.98%,穿透硫容为4.03%。     

高温焦炉气脱硫剂铁酸锌的制备及改性

采用超声共沉淀法以铁酸锌为活性中心、CuO为助剂、聚乙二醇为分散剂,制备了CuO-ZnFe2O4脱硫剂,采用XRD、SEM等手段对脱硫剂的结构和形貌进行了表征分析,发现在铁酸锌晶体中成功引入铜物种,并均匀分散在其中。以固定床反应器对脱硫剂的脱硫性能进行评价,考察了助剂的最佳添加量,及在最佳添加量条件下脱硫剂的再生稳定性。结果显示引入CuO助剂后的脱硫剂活性组分的分散性增强,脱硫过程中H2S气体可以更好的与活性位接触,提高了脱硫剂脱硫性能。     

复合金属氧化物脱除羰基硫的研究

采用共沉淀法制备铁锰复合金属氧化物脱硫剂,从温度、空速和羰基硫浓度几个方面考察对脱硫剂脱硫性能的影响.实验结果表明,该脱硫剂在250℃～350℃,强还原性气氛下,具有较高的有机硫脱硫精度和较大硫容.实验还考察了氧化锌、氧化铜、氧化镍和氧化铈几种添加剂对脱硫剂脱硫效果影响,结果表明,脱硫剂中添加氧化镍和氧化铈后脱硫精度有较大提高,出口羰基硫浓度低于0.1×10-6,添加氧化铜和氧化锌的脱硫精度为0.2×10-6;此外,添加氧化锌脱硫剂硫容较大,穿透硫容为25%,而添加氧化铈的脱硫剂硫容相对较小.     

影响氧化锌脱硫的因素

在氧化锌脱硫剂脱硫机理的基础上,分析了工艺条件,如压力、温度、空速、反应器设计、脱硫剂装填以及脱硫剂本身对脱硫性能的影响,指出很多工艺因素影响氧化锌脱硫剂脱除H2S的效率。可能的情况下,改变操作条件(如后期适当提高操作温度),可以进一步发挥氧化锌脱硫剂的性能。不同配方的氧化锌脱硫剂有不同的吸收特性。用纯氧化锌制成的高密度的脱硫剂不如将脱硫剂制成疏松多孔结构的脱硫剂有效。加入合适的助剂也可以进一步提高氧化锌的脱硫能力。     

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.     

循环流化床锅炉添加石灰石脱硫对性能设计的影响

定量分析了循环流化床锅炉添加石灰石脱硫后的锅炉性能计算中燃烧产物计算的新方法， 并通过实例分析总结出至关重要的影响因素。     

高温脱硫的研究进展

论述了煤气高温脱硫的重要意义及研究状况，并着重阐述了几种目前国际上普遍关注的高温脱硫剂的研究状况，最后就我国的情况提出一些建议。     

EFFICIENT DESULFURIZATION IN O2/CO2 COMBUSTION: DEPENDENCE ON COMBUSTION CONDITIONS AND SORBENT PROPERTIES

Based on experiments on desulfurization, CaSO₄ decomposition, and a system approach using theoretical analysis, efficient in-furnace desulfurization in O₂/CO₂ combustion was investigated. The influence of combustion conditions and sorbent properties on system desulfurization efficiency was clarified. The global desulfurization efficiency was found to increase with O₂ purity. The global desulfurization efficiency in a dry recycle was higher than that in a wet recycle. The global efficiency of in-furnace desulfurization decreased with initial O₂ concentration. As the temperature increased, the global desulfurization efficiency increased first and then decreased due to the decomposition of CaSO₄. In the temperature range investigated, the global desulfurization efficiency in O₂/CO₂ coal combustion was much higher than that of conventional coal combustion in air. The global desulfurization efficiency decreased with sorbent size. When the particle radius decreased to one quarter, the global desulfurization efficiency doubled, becoming as high as 80%. The global desulfurization efficiency was very different among the three sorbents investigated, whether in O₂/CO₂ combustion or in conventional air combustion. The global desulfurization efficiency increased in the order of Ca(OH)₂, scallop, and limestone in O₂/CO₂ combustion, but in the order of scallop, Ca(OH)₂, and limestone in conventional air combustion. Nevertheless, all three sorbents demonstrated much higher desulfurization efficiency in O₂/CO₂ combustion than in conventional air combustion.     

THE REACTIVITY AND DURABILITY OF ZINC FERRITE HIGH TEMPERATURE DESULFURIZATION SORBENTS

Cylindrical pellets of zinc ferrite high temperature desulfurization sorbent have been prepared using a number of formulation recipes and induration conditions. Physical and structural properties of the resultant sorbents were measured, and reactivity and durability screening tests were carried out using a single pellet electrobalance reactor. The formulation variables studied were ZnO to Fe₂O₃ ratio, Fe₂O₃ source, and the addition of inorganic (bentonite) and organic (methocel) binders to the sorbents. Pellet induration conditions ranged from 0.25 hours at 815^°C to 4.0 hours at 1038°C. Stronger pellets having greater attrition resistance resulted when 5% bentonite was added to the formulation recipe and when the pellets were indurated at high temperature for extended times. In contrast, bentonite content was not a significant factor in determining sorbent reactivity and durability, both of which were improved by mild induration conditions. Sorbent regeneration temperature was found to be an important factor in improving reaction durability, as was the addition of 0.5% methocel to the formulation recipe. Pellets containing catalyst-grade Fe₂O₃ were more reactive than those containing pigment-grade Fe₂O₃. This effect, however, was less important than the effect of induration conditions.     

副产物含量对栲胶脱硫液性质的影响

在栲胶脱硫生产过程中除了主反应外,同时还伴随Na2S2O3,Na2SO4,NaSCN及NaHCO3等盐类生成的副反应.这些副产物的生成会影响栲胶脱硫液的性质,并最终影响整个脱硫循环工艺的稳定.为了避免这些影响,从表面张力、黏度和密度三个方面分析了Na2S2O3,Na2SO4,NaSCN和NaHCO3四种栲胶脱硫工艺的副产物对栲胶脱硫溶液的影响.结果表明,副产物的积累可以引起脱硫溶液表面张力的下降以及溶液黏度和密度的增加,从而引起脱硫工艺中操作条件的改变,最终影响整个系统的脱硫效率.     

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.     

噻吩催化裂化脱硫机理的量子化学分析

采用半经验AM1计算方法,利用静态理论对噻吩在分子筛催化剂上的催化裂化脱硫机理进行了量子化学计算研究,通过对噻吩分子和可能产生的中间正碳离子的量子化学计算,得到各中间反应所需的能量,从而判断噻吩催化裂化脱硫反应的趋势,证实了氢转移反应在催化裂化脱硫中所起的作用.当噻吩处在催化裂化条件下,正碳离子反应活跃,易与烷烃裂化生成的α烯烃加成,进一步与烷烃发生氢转移饱和后裂化脱硫.由于氢转移反应为放热反应,因而降低反应温度有利于噻吩催化裂化脱硫.