还原温度对Fe-Mo催化剂性质及F-T合成性能的影响

研究了还原温度对Fe-Mo催化剂性质及费托(F-T)合成性能的影响。采用N₂物理吸附、X射线衍射、穆斯堡尔谱和H₂程序升温脱附技术对催化剂进行了表征。结果表明,随还原温度升高,金属铁晶粒粒径增大,金属铁上的H₂吸附量先升后降;催化剂还原度提高,反应态催化剂碳化铁含量递增。催化剂F-T合成性能在280 ℃、1.5 MPa、2 000 h^-1、合成气H₂/CO比为2.0条件下在固定床反应器中测试。反应结果表明,随还原温度提高,催化剂接近稳态时的活性和重质烃选择性(C₅⁺)先升后降,而甲烷选择性则先降后升。350 ℃还原催化剂具有最佳F-T合成反应性能。     

鼓泡浆态床费托合成（FTS）的模拟：数值分析

建立了浆态床反应器模型,该模型考虑了气相、液相的轴向分散及催化剂沿床层的非均匀分布。通过与Ｒｈｅｉｎｐｒｅｕｓｅｎ－Ｋｏｐｐｅｒｓ示范厂文献实验数据的对比,检验了模型的有效性。依据模型,计算分析了反应物、产物的浓度分布,气液两相的Ｈ２／ＣＯ变化及ＦＴＳ与ＷＧＳ对合成气转化的贡献。模拟结果给出了浆态床为何能够利用贫氢合成气的合理解释     

低温高活性熔铁催化剂上的超临界相费托合成反应

在固定床反应器中超临界相条件下研究了熔铁催化剂上的费托合成反应,发现在超临界介质中反应物和产物更容易扩散,较好地抑制了催化剂表面非活性碳的沉积,从而提高了费托合成反应中的CO转化率和烯烃选择性,增加了链增长因子,降低了甲烷选择性.同时,考察了超临界介质、反应温度、压力、H2/CO比和空速等条件对费托合成反应的影响.结果表明,C5-8正构烷烃在催化剂活性温度下都是适宜的超临界介质.当温度和压力都在介质的临界点以上时,介质表现出较好的传质与传热性能,可改善费托合成反应性能.     

STUDIES ON FISCHER TROPSCH SYNTHESIS OVER Fe-Cu-K CATALYST Ⅰ.CATALYTIC PERFORMANCE

The influence of reaction pressure, temperature, space velocity (GHSV), particle size of catalyst and H2/CO ratio of feed-gas on the steady-state product distribution, conversion of CO, H2 and syngas, olefin to paraffin ratio and CO2/ H2O ratio for FTS reaction were investigated using a coprecipitated copper- potassium promoted iron catalyst. The test was carried out in a fixed-bed reactor. Increasing the reaction temperature from 493. 2 to 5-13. 2 K shifted the hydrocarbon distribution toward the heavier hydrocarbons (C5-C23) and selectively increased CO conversion to CO2. The hydrocarbon distribution was found to be dependent on the H2/CO feed-gas ratio in the range from 1.23 to 2. 22. The CO2/H2O ratio in product decreased as the flow of feed-gas rate increased, which suggests that H2O is a primary product and its reaction with CO to form CO2 occurs via a secondary process. The CO conversion increased with the decrease of catalyst particle size from 10 to 60 mesh (2. 0- 0. 3 mm), while the CO convers     

Activation pressure studies with an iron-based catalyst for slurry Fischer-Tropsch synthesis

Fischer-Tropsch synthesis (FTS) was carried out with an industrial iron-based catalyst (100Fe/5Cu/6K/16SiO2, by weight) under the baseline conditions in a stirred tank slurry reactor (STSR). The effects of activation pressure on the catalyst activity and selectivity were investigated. It was found that iron phase compositions, textural properties, and FTS performances of the catalysts were strongly dependent on activation pressure. The high activation pressure retards the carburization. Møssbauer effect spectroscopy (MES) results indicated that the contents of the iron carbides clearly decrease with the increase of activation pressure, especially for the activation pressure increasing from 1.0 MPa to 1.5 MPa, and the reverse trend is observed for superparamagnetic Fe3+ (spm). The higher content of Fe3+ (spm) results in the higher amount of CO2 in tail gas when the catalyst is reduced at higher pressure. The catalyst activity decreases with the increase of activation pressure. The high quantity of iron carbides is necessary to obtain high FTS activity. However, the activity of the catalyst activated in syngas can not be predicted solely from the fraction of the carbides. It is concluded that activation with syngas at the lower pressure would be the most desirable for the better activity and stability on the iron-based catalyst.     

Effect of Sulfate on an Iron Manganese Catalyst for Fischer-Tropsch Synthesis

The effect of sulfate on Fischer-Tropsch synthesis performance was investigated in a slurry- phase continuously stirred tank reactor(CSTR)over a Fe-Mn catalyst.The physiochemical properties of the catalyst impregnated with different levels of sulfate were characterized by N_2 physisorption,X-ray photoelectron spectroscopy(XPS),H_2(or CO)temperature-programmed reduction(TPR),Mφssbauer spectroscopy,and CO_2 temperature-programmed desorption(TPD).The characterization results indicated that the impregnated sulfate slightly decreased the BET surface area and pore volume of the catalyst, suppressed the catalyst reduction and carburization in CO and syngas,and decreased the catalyst surface basicity.At the same time,the addition of small amounts of sulfate improved the activities of Fischer- Tropseh synthesis(FTS)and water gas shift(WGS),shifted the product to light hydrocarbons(C_1-C_(11)) and suppressed the formation of heavy products(C_(12 )).Addition of SO_4~(2-)to the catalyst improved the FTS activity at a sulfur loading of 0.05-0.80 g per 100 g Fe,and S-05 catalyst gave the highest CO conversion(62.3%),and beyond this sulfur level the activity of the catalyst decreased.     

Ru和Cu助剂对费托合成Fe基催化剂反应性能的影响

研究了Ru和Cu助剂对无K的费托(F-T)合成Fe基催化剂的织构性质、物相结构、还原和碳化行为的影响.在n(H2)/n(CO)=2.0,t=260℃,P=1.5MPa和GHSV=2000h-1的条件下,采用固定床反应器考察了Ru,Cu助剂对Fe基催化剂费托合成反应性能的影响.采用低温N2物理吸附、X射线衍射、穆斯堡尔谱...     

硅对铁基费-托合成催化剂的影响

用共沉淀法制备了一系列不同硅含量的铁基催化剂,采用N2吸附和原位X射线衍射对催化剂进行了表征,在固定床反应器中考察了催化剂的费-托合成反应活性、选择性和稳定性.结果表明,含硅的催化剂具有较大的比表面积和较小的平均孔径,在CO还原及费-托合成反应中生成的碳化铁物种的稳定性比不含硅的催化剂高.在费-托合成反应中,不含硅的催化剂具有较高的初始活性,但易失活;含硅的催化剂具有较低的初始活性,但稳定性较高.Fe7C3是活性最高的碳化铁物种.随着硅含量的增加,催化剂的费-托合成反应更易生成低碳数产物.     

含氮合成气在三相淤浆床-固定床中直接合成二甲醚

在三相淤浆床－固定床反应装置中,研究含氮合成气直接合成二甲醚。使用双功能混合催化剂,粒度为0.15 mm～0.18 mm。在220 ℃～260 ℃、3.0 MPa～7.0 MPa、空速1 000 mL·g-1·h-1时考察了温度、压力及两种反应器中催化剂的装填比例对CO转化率及二甲醚选择性的影响。结果表明,一氧化碳转化率随反应压力的增加而提高,随着温度升高二甲醚的选择性变化不大,CO转化率的升高较明显,因此在催化剂活性适宜的温度范围内,该反应装置可以采用较高的反应温度。当260 ℃、7.0 MPa、三相床与固定床中催化剂比例为1∶1时,CO的转化率可达84.5％,二甲醚的选择性为78.7％。淤浆床－固定床反应装置具有操作稳定性好、CO转化率高的优点。催化剂在该装置中反应370 h活性没有明显下降。     

超临界和近临界条件下Fischer Tropsch合成研究：溶剂的影响

研究了超临界和近临界条件下费托合成过程中溶剂对反应行为的影响。反应在固定床反应器中进行，催化剂为Co/SiO2，所选择的溶剂有两类：纯溶剂（正戊烷和正己烷）和混和溶剂（由正己烷和少量的C5~10烃组成）。结果表明,正己烷分压对CO转化率影响很小，但是产物中1 烯烃含量随正己烷分压增加而增加，超临界条件下1 烯烃含量明显高于非临界条件下。溶剂的种类对CO转化率、CH4和CO2选择性以及产物炭分布影响不大。这一结果表明为了减少溶剂用量，对含有适量轻组分（C5~10）的正己烷溶剂进行循环使用是可行的。结果同时表明与正己烷相比，混和溶剂（25%正己烷和75%正葵烷）具有较高的1 烯烃选择性。     

Mo 和 Cu 助剂对 FeK/SiO2 催化剂费托合成性能的影响

 研究了 Mo 和 Cu 助剂对 FeK/SiO₂ 催化剂的性质及费托 (F-T) 合成性能的影响. 采用 N₂ 物理吸附、H₂ 程序升温还原、X 射线衍射、穆斯堡尔谱和 X 射线光电子能谱技术对催化剂进行了表征. 结果表明, Mo 加入后与 Fe 产生了较强的相互作用, 抑制了催化剂的还原和碳化; Cu 助剂的加入促进了催化剂的还原和碳化; 当 Mo 和 Cu 共同加入后, 催化剂的还原和碳化行为与单独加入 Cu 助剂时相似. 催化剂 F-T 合成性能在固定床上于 280 ^oC, 1.5 MPa, 2 000 h^-1, H₂/CO = 2.0 的合成气中测试. 结果表明, Mo 的加入降低了催化剂活性, 但提高了重质烃 (C₅₊) 的选择性; Cu 的添加提高了催化剂的活性, 但对稳定 C₅₊选择性作用不明显. Mo 和 Cu 共同加入后, 催化剂既表现出较为稳定的 C₅₊选择性, 同时其活性也没有降低.     

Effect of Potassium Addition on Coprecipitated Iron Catalysts for Fischer-Tropsch Synthesis Using Bio-oil-syngas

The effects of potassium addition and the potassium content on the activity and selectivity of coprecipitated iron catalyst for Fischer-Tropsch synthesis (FTS) were studied in a fixed bed reactor at 1.5 MPa, 300 o C, and contact time (W=F) of 12.5 gcath/mol using the model bio-oil-syngas of H2/CO/CO2/N2 (62/8/25/5, vol%). It was found that potassium addition increases the catalyst activity for FTS and the reverse water gas shift reaction. Moreover, potassium increases the average molecular weight (chain length) of the hydrocarbon products. With the increase of potassium content, it was found that CH4 selectivity decreases and the selectivity of liquid phase products (C5+) increases. The characteristics of FTS catalysts with different potassium content were also investigated by various characterization measurements including X-ray diffraction, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller surface area. Based on experimental results, 100Fe/6Cu/16Al/6K (weight ratio) was selected as the optimal catalyst for FTS from bio-oil-syngas. The results indicate that the 100Fe/6Cu/16Al/6K catalyst is one of the most promising candidates to directly synthesize liquid bio-fuel using bio-oil-syngas.     

Effect of Manganese Incorporation Manner on an Iron-Based Catalyst for Fischer-Tropsch Synthesis

A systematic study was undertaken to investigate the effects of the manganese incorpo- ration manner on the textural properties,bulk and surface phase compositions,reduction/carburization behaviors,and surface basicity of an iron-based Fischer-Tropsch synthesis(FTS)catalyst.The cata- lyst samples were characterized by N_2 physisorption,X-ray photoelectron spectroscopy(XPS),H_2(or CO)temperature-programmed reduction(TPR),CO_2 temperature-programmed desorption(TPD),and M(?)ssbauer spectroscopy.The FTS performance of the catalysts was studied in a slurry-phase continuously stirred tank reactor(CSTR).The characterization results indicated that the manganese promoter incor- porated by using the coprecipitation method could improve the dispersion of iron oxide,and decrease the size of the iron oxide crystallite.The manganese incorporated with the impregnation method is enriched on the catalyst's surface.The manganese promoter added with the impregnation method suppresses the reduction and carburization of the catalyst in H_2,CO,and syngas because of the excessive enrichment of manganese on the catalyst surface.The catalyst added manganese using the coprecipitation method has the highest CO conversion(51.9%)and the lowest selectivity for heavy hydrocarbons(C_(12 )).     

结构助剂SiO2、Al2O3对铁基催化剂浆态床F-T合成性能的影响

采用连续共沉淀与喷雾干燥成型技术相结合的方法制备了微球状Fe/Cu/K/SiO2和Fe/Cu/K/Al2O3催化剂,研究SiO2和Al2O3作为结构助剂对铁基催化剂吸附行为、炭化行为及F-T合成反应性能的影响。表征结果表明,与Al2O3相比较,SiO2抑制了H2的吸附,但促进了CO的吸附,有利于催化剂的炭化。催化剂在260℃、1.5MPa、H2/CO=0.67和2000h-1下的浆态床F-T合成反应评价表明,Fe/Cu/K/SiO2催化剂具有较高的F-T合成活性、高的水煤气变换反应（WGS）活性,且其烃产物选择性明显向高炭数方向偏移,而Fe/Cu/K/Al2O3催化剂则表现出较低的F-T合成活性、低的水煤气变换反应（WGS）活性和高的轻质烃选择性。但Fe/Cu/K/Al2O3催化剂比Fe/Cu/K/SiO2催化剂具有更好的运行稳定性。     

Fe/SiO_2纳米复合物上合成气制低碳烯烃催化性能研究

分别采用一步合成法和常规共沉淀法制备了Fe/SiO2催化剂,通过N2物理吸附、X射线衍射、透射电镜、傅里叶变换红外光谱和程序升温还原等方法对催化剂进行了表征,并在固定床反应器中对其费托合成制低碳烯烃的催化性能进行了评价。结果表明,与共沉淀铁基催化剂不同,采用一步合成法制备的纳米复合物主要由Fe3O4相构成,形貌呈规则球形,平均粒径为30 nm,尺寸分布窄,更容易还原。一步合成法制得的Fe/SiO2催化剂对费托合成反应具有较高的活性和低碳烯烃选择性、较低的甲烷选择性和良好的稳定性。     

Dynamic modeling of a H2O-permselective membrane reactor to enhance methanol synthesis from syngas considering catalyst deactivation

In this paper,the effect of water vapor removal on methanol synthesis capacity from syngas in a fixed-bed membrane reactor is studied considering long-term catalyst deactivation.A dynamic heterogeneous one-dimensional mathematical model that is composed of two sides is developed to predict the performance of this configuration.In this configuration,conventional methanol reactor is supported by an aluminasilica composite membrane layer for water vapor removal from reaction zone.To verify the accuracy of the considered model and assumptions,simulation results of the conventional methanol reactor is compared with the industrial plant data under the same process condition.The membrane reactor improves catalyst life time and enhances CO2 conversion to methanol by overcoming the limitation imposed by thermodynamic equilibrium.This configuration has enhanced the methanol production capacity about 4.06% compared with the industrial methanol reactor during the production time.     

Characterization and catalytic behavior of EDTA modified silica nanosprings (NS)-supported cobalt catalyst for Fischer-Tropsch CO-hydrogenation

The effect of ethylene diamine tetraacetic acid(EDTA) modification on the physico-chemical properties and catalytic performance of silica nanosprings(NS) supported cobalt(Co) catalyst was investigated in the conversion of syngas(H~(2+) CO) to hydrocarbons by Fischer-Tropsch synthesis(FTS). The unmodified Co/NS and modified Co/NS-EDTA catalysts were synthesized via an impregnation method. The prepared Co/NS and Co/NS-EDTA catalysts were characterized before the FTS reaction by BET surface area,X-ray diffraction(XRD),transmission electron microscopy(TEM),temperature programmed reduction(TPR),X-ray photoelectron spectroscopy(XPS),differential thermal analysis(DTA) and thermogravimetric analysis(TGA) in order to find correlations between physico-chemical properties of catalysts and catalytic performance. FTS was carried out in a quartz fixedbed microreactor(H_2/CO of 2 ∶1,230 ℃ and atmospheric pressure) and the products trapped and analyzed by GC-TCD and GC-MS to determine CO conversion and reaction selectivity. The experimental results indicated that the modified Co/NS-EDTA catalyst displayed a more-dispersed phase of Co_3O_4 nanoparticles(10.9%) and the Co_3O_4 average crystallite size was about 12.4 nm. The EDTA modified catalyst showed relatively higher CO conversion(70.3%) and selectivity toward C_(6-18)(JP-8,Jet A and diesel) than the Co/NS catalyst(C_(6-14))(JP-4).     

Mass- and heat-transfer-enhanced catalyst system for Fischer-Tropsch synthesis in fixed-bed reactors

Fischer-Tropsch synthesis (FTS) was carried out using Al₂O₃-supported Co catalyst coated on metallic monolith. Considering the liberation of a large amont of heat from the highly exothermic FTS reaction, catalytic activity of Co catalyst coated on metallic monolith was tested and compared with that of pellet-type catalysts. The reaction was carried out in a conventional tubular fixed-bed reactor and simulated distillation (SIMDIS) analysis method was used to determine the liquid products distribution. Proper control of degree of reaction, as well as the reaction temperature gave rise to a shift of products selectivity toward higher hydrocarbons, especially C₁₃?C₁₈ diesel range hydrocarbons.     

费托反应本征动力学中合成气分压对反应速率的影响

利用高通量动力学反应器测量了本征条件下钴基费托催化剂上反应物消耗速率rCO和产物生成速率rCH4随固定床床层的分布,并考察了它们在不同入口分压(p0CO,p0H2)条件下的变化.结果表明,入口氢碳比(H/C)0=p0H2/p0CO为影响速率的敏感外部变量,反应速率随(H/C)0的增加而加快;而合成气总压p0H2+CO则...     

固定床F-T合成反应器的稳态和动态行为特性 I.数学模型及其数值计算方法(英文)

讨论了固定床反应器模型的建立过程和工作步骤,确定固定床Ｆ－Ｔ合成反应器用非均相二维模型来描述。总结评价了固定床反应器模型方程的数值计算方法,确定了固定床Ｆ－Ｔ合成反应器模型方程的数值计算方法。