MEA-PEHA复合溶液吸收/解吸CO_2气体实验研究

为了开发性能优良的MEA/烯胺复配吸收剂,本研究采用自主设计的CO_2捕集吸收/解吸装置,通过测试烯胺及MEA/烯胺复配吸收剂的吸收速率、吸收量、解吸速率、解吸率等指标确定最佳单组分烯胺溶剂及其与MEA的最佳复配溶剂。研究结果表明,单溶剂中五乙烯六胺(PEHA)的吸收和解吸效果最好,解吸温度最低,是最佳的单组分烯胺吸收剂;不同物质的量浓度比(4∶6~9∶1)的MEA-PEHA复配溶液中,物质的量浓度配比为5∶5的MEA-PEHA复配溶液饱和吸收量最大(1.72mol),平均吸收速率最高(81.74×10~(-6) mol/s),解吸温度最低(68℃),平均解吸速率最大(137.09×10~(-6) mol/s)以及解吸率较高(95.23%),是CO_2捕集的最佳MEA-PEHA混胺体系。     

基于MDEA复合吸收剂捕集EOR产出气中二氧化碳

采用自主开发的间歇反应器,以CO_2和CH_4体积比为50:50的混合气体作为EOR产出气的模拟气,MDEA为主吸收剂,分别添加MEA、DEA、PZ和AMP作为活化剂,研究优选最佳的强化采油(EOR)产出气CO_2回收MDEA复配溶液。通过饱和吸收量、平均吸收速率、平均再生速率、再生率以及反应热对比分析,得出各体系最佳配比分别为:32%MDEA+3%AMP、32%MDEA+3%PZ、30%MDEA+5%MEA、30%MDEA+5%DEA。对四种优选的配方体系的吸收性能和解吸性能进行综合分析,得出PZ对MDEA溶液的吸收和再生性能提升最大。32%MDEA+3%PZ复配溶液的CO_2吸收量为0.868mol/mol,平均吸收速率为6.718×10~(-3)mol/min,平均再生速率为23.122×10~(-3)mol/min,溶液再生率为94.2%。     

MEA二元复合胺溶液对CO2吸收的研究进展

全球温室效应日益加剧,CO₂减排刻不容缓,乙醇胺(MEA)法作为目前工业上应用最广泛、技术最成熟的烟气CO₂吸收方法,具有吸收速率快、成本低的优点,但是其能耗大、吸收量小和易损耗的缺点也很明显。针对目前常见的MEA二元复合胺溶液展开对比分析,阐述了MEA二元复合胺溶液的研究进展,总结了MEA吸收溶液中加入其他醇胺溶液形成二元复合胺溶液后在吸收速率、吸收量和再生能耗等方面对CO₂吸收效果不同程度的改善情况。基于总结与分析,提出了吸收剂开发需要从吸收机理、溶解度、吸收负荷、解吸速率、解吸操作条件以及再生能耗等方面进行综合比选的思路,可为新型吸收剂的开发提供一定的指导。     

MEA溶液捕集CO_2的反应热实验研究

单乙醇胺(MEA)捕集CO_2具有吸收速率快、吸收量大等优点,是CO_2化学吸收法中应用最普遍的吸收剂。本文利用自主开发的量热系统测量了MEA溶液吸收CO_2的吸收热、解吸热以及吸收量,考察了CO_2负载率、温度、压力、活化剂等对吸收热、解吸热和吸收量的影响。研究表明:吸收热随温度的增加而下降;在温度相同时,吸收热随CO_2负载率的增大而减小,随吸收剂浓度的增大而增大;压力对吸收热的影响不大,但压力越大,对CO_2的吸收量越大;活化剂的添加有效的降低了单一溶剂MEA的吸收热和解吸热。此外,解吸过程中汽化潜热的回收利用可有效降低能耗。     

MEA溶液捕集CO2工艺优化及能耗分析

在对单乙醇胺(MEA)溶液捕集CO2解吸能耗分析的基础上,进一步探讨了液气比、MEA溶液浓度及MEA溶液吸收温度对CO2吸收效率和解吸能耗的影响。在模拟计算工况条件下,根据系统中能耗计算公式,可求得最佳液气比为5.6 L/m3。提高液气比有利于CO2的捕集,但当液气比大于5.6 L/m3时,CO2捕集系统中的单位能耗将增加;在吸收液浓度小于40%时,提高吸收剂溶液的质量浓度可以降低单位解吸能耗,但吸收剂质量浓度并不是越高越好,本工况条件下的适宜浓度范围为35%～40%;同时,MEA溶液在吸收-解吸过程中存在氧化和腐蚀问题。因此,CO2捕集系统工艺参数的优化是降低MEA溶液捕集CO2操作费用的关键。     

N-甲基二乙醇胺和三乙烯四胺混胺吸收CO_2性能的研究

以N-甲基二乙醇胺(MDEA)和三乙烯四胺(TETA)为原料配制5种混胺总含量为30%(φ)的吸收剂用于吸收CO2,在自制的吸收/解吸实验装置中考察混胺配比和吸收剂使用次数对吸收剂性能的影响。实验结果表明,吸收剂Ⅲ(26%(φ)MDEA+4%(φ)TETA)的吸收/解吸性能最好;在101.33 Pa和298.15 K的条件下,吸收剂Ⅲ对CO2的吸收量为0.8 699 mol/mol,平均吸收速率为1.880 mmol/s;在101.33 Pa和383.15 K的条件下,吸收剂Ⅲ对CO2的解吸率为91.61%;与第1次使用相比,吸收剂Ⅲ第4次使用时,CO2吸收量降低了26.8%,CO2解吸率降低了15.7%;使用4次后,吸收剂Ⅲ的质量和p H虽有所降低,但仍具有较佳的吸收/解吸性能。     

MEA-AMP二元复配溶液吸收烟气中二氧化碳的实验研究

实验以乙醇胺(MEA)为主体,加入定量的新型空间位阻胺2-氨基-2-甲基-1-丙醇(AMP)配成复合胺,研究了该复合胺液对CO_2吸收和再生性能,并与同浓度的MEA、二乙醇胺(DEA)溶液进行了比较,筛选了MEA-AMP体系中最佳吸收液。以搅拌实验装置研究了MEA-AMP不同配比的复合胺溶液吸收和解吸模拟烟道气中CO_2特性,揭示了吸收速率、吸收容量和酸碱度与时间之间的关系,并与目前工业应用较广的MEA、DEA溶液进行了对比分析;对CO_2初始逸出温度、试液再生温度、试液再生率、再生pH值下降率进行了记录分析。结果表明,0.7 mol/L MEA-0.3 mol/L AMP吸收容量最大,为0.329 moL;再生温度最低,为100℃,是MEA-AMP复合胺体系中最佳配比溶液。     

MDEA为主体的复配胺液选择性脱硫性能实验研究

在总浓度为2 mol/L的条件下,运用小型反应釜,采用恒压吸收法和恒容吸收法,对以MDEA为主体、DGA与AMP为添加剂的复配胺液进行不同物质的量比下选择性吸收H_2S性能的实验研究。通过分析气相浓度、吸收速率、酸气脱除率及选择性因子,优选出不同复配胺液在此浓度下选择性脱硫的最优配比。实验结果表明:2mol/L MDEA+DGA复配胺液在物质的量比为10∶3时,对原料气中H_2S的吸收速率、脱除率均较高,对CO_2的吸收速率、脱除率均较低,选择性因子最大,为该复配胺液的最优配比;2mol/L MDEA+AMP复配胺液在物质的量比为10∶3时,对原料气中H_2S的吸收速率、脱除率均较高,对CO_2的吸收速率、脱除率均较低,选择性因子最大,为该复配胺液的最优配比。     

高含CO2天然气脱碳工艺中MDEA活化剂优选

国内高含CO_2天然气处理装置主要采用活化MDEA脱碳工艺。以DEA、MEA、PZ为活化剂,总胺物质的量浓度控制在4 mol/L。利用HYSYS软件建立运算模型,研究这3种活化MDEA溶液对CO_2的吸收性能和解吸性能,通过分析认为,高含CO_2天然气深度脱碳处理宜采用PZ为活化剂。对PZ的活化机理进行研究,发现PZ作为活化剂的效果远胜于DEA和MEA。最后,分析不同吸收温度及CO_2分压下PZ浓度变化对活化性能的影响,发现加入少量PZ即可大幅提高PZ活化MDEA溶液与CO_2反应速率,在不同CO_2分压和吸收温度的条件下均能满足高含CO_2天然气的脱碳处理要求,适应性较强,建议活化MDEA溶液中PZ的质量分数为3%~5%。     

填料塔中混合胺钛基纳米流体对高浓度CO2的捕集试验研究

模拟了石油化工废气排放过程中高浓度CO₂(50%，体积分数)尾气处理场景。对伯胺和叔胺溶液进行复配，建立了兼具快速反应性能和高吸收容量的混合胺钛基纳米流体。自主设计并搭建10 t/a规模填料塔CO₂吸收-解吸循环试验系统，考察了纳米流体吸收剂在填料塔中的CO₂吸收-解吸综合强化机制。研究发现，相较混合胺而言，纳米流体吸收剂最大可提升40%的吸收-解吸循环容量。提高贫液中的CO₂负载会削弱纳米颗粒对吸收剂捕集CO₂性能的促进作用。当CO₂负载达到0.4 mol/mol(1 mol胺负载0.4 mol CO₂)时，纳米流体吸收剂的体积总传质系数和混合胺吸收剂基本一致。体系中纳米颗粒之间的相互作用增强，使液相内部形成微对流，可提升捕集体系的CO₂吸收性能。但当纳米颗粒质量分数超过0.12%时，液相中的微对流和固体穿梭效应会因粒子团聚而削弱。因此，需要在循环过程中采取有效措施对团聚的纳米颗粒进行分散。如何通过耦合外部扰动...     

H6P2W18O62/MCM-48催化剂的制备、表征及催化绿色合成己二酸

以MCM-48为载体,通过浸渍法制备了H6P2W18O62/MCM-48催化剂,并采用FT-IR、XRD、SEM、EDS对催化剂进行表征。以微波促进30%(质量分数)H2O2氧化环己酮合成己二酸反应为探针,考察了H6P2W18O62/MCM-48的催化性能,并通过正交实验确定了优化的工艺条件。结果表明,采用H6P2W18O62负载量40%的H6P2W18O62/MCM-48催化剂,在优化的合成己二酸的工艺条件下,即催化剂质量分数(以环己酮质量计)5.1%、n(C6H10O)∶n(H2O2)∶n(H2C2O4.2H2O)=100∶450∶1.88、反应温度95℃、微波功率300 W、反应时间3.5h,己二酸收率可达81.3%;催化剂重复使用5次,己二酸收率仍可达到64.6%。     

Nanocatalysts: Effect of Active-phase and Promoter on Catalytic Properties and Performance in the Hydrodesulfurization Reaction

The influence of various amounts of phosphorus addition on performance of NiMoP/Al₂O₃ and CoMoP/Al₂O₃ nanocatalysts was examined in hydrodesulfurization of thiophene. The nanocatalysts were synthesized via sonochemical technique. The prepared samples were characterized by XRD, FESEM, BET, and FTIR analysis. The catalytic activity in hydrodesulfurization reaction was investigated in a batch stirred slurry reactor at 160°C and atmospheric pressure. The characterizations confirmed highly dispersion of active phase and formation of amorphous AlPO₄ species on the support surface. The results obtained from thiophene hydrodesulfurization showed the nanocatalysts contained 1 wt% of phosphorus had the highest activity. The CoMoP/Al₂O₃ and NiMoP/Al₂O₃ nanocatalysts with optimum phosphorus loading nearly gave 100% conversion of thiophene, so that the sulfur compound concentration in final solution was less than 50 ppm.     

Petroleum Hydrocarbons Extraction Efficiency of Carbon Tetrachloride and Trichlorotrifluoroethane: A Comparative Study

Abstract

Petroleum hydrocarbons (PHC) contaminated water samples, prepared in laboratory, were analyzed using infrared spectroscopy to compare PHC extraction efficiency of carbon tetrachloride (CCl₄) and trichlorotrifluoroethane (C₂Cl₃F₃) solvents. The comparison of the results illustrated that PHC extraction efficiency of CCl₄ was greater than C₂Cl₃F₃. The higher extraction efficiency of CCl₄ was ascribed to its more non-polar nature and higher polarity index. This study supported the selection and use of CCl₄ for extraction and quantification of PHC of groundwater samples of the projects carried out in the department.     

Nanosized Platinum-Loaded H-ZSM-5 Zeolite Catalysts for n-Hexane Hydroconversion

Abstract

A series of nanosized platinum-containing catalysts was successfully loaded on/in zeolite H-ZSM-5 via exchanging the zeolitic proton with platinum from Pt tetramine dichloride complex. Another series of Pt/H-ZSM-5 catalysts was prepared via wet impregnation of H₂PtCl₆ solution for comparison. The latter series was found to produce lower Pt dispersion. Pt dispersion was determined by H₂ chemisorption. Catalyst characterization via ammonia temperature-programmed desorption (TPD), temperature-programmed reduction (TPR), and transmission electron microscopy (TEM) was examined for all catalysts and showed large differences in particle sizes. The data on n-hexane reactions of the catalysts of both series confirmed the formation of Pt nanoparticles in the exchanged catalysts. The relatively lower density and strength of acid sites acquired by Pt-exchanged catalysts contributed to this difference; stronger acid sites in the impregnated catalysts are in favor of hydrocracking reactions, which inhibit isomerization selectivity.     

Characterization of Al2O3–ZrO2 Mixed Oxide Supported Mo Hydrotreating Catalyst

Abstract

A series of molybdenum catalysts supported on Al₂O₃–ZrO₂ mixed oxide containing 50% ZrO₂ and 50% Al₂O₃ were prepared by incipient wetness technique and characterized by BET surface area, X-ray diffraction, temperature programmed reduction and oxygen chemisorption. The catalytic activities for hydrodesulphurization (HDS), hydrogenation (HYD), and hydrocracking (HYC) were determined using thiophene, cyclohexene, and cumene as model compounds, respectively. Results indicate that up to 8 wt% Mo loading, the catalyst is well dispersed and crystallite growth occurred beyond this loading. Also both oxygen uptake and catalytic activities increase with Mo loading up to 8 wt% and then decreases at higher loading. A linear correlation was obtained between oxygen uptake and all catalytic activities and the correlation coefficients obtained suggest that the order of catalytic activities for HDS, HYD, and HYC is: HDS > HYD > HYC. Furthermore, the catalytic activities of the mixed oxide supported catalyst for HDS, HYD, and HYC were higher than those supported on pure alumina and pure zirconia. The incorporation of 3% Co on 8% Mo catalyst was determined to result in enhanced activity for HDS, HYD, and HYC.     

复合SiO2-WO3催化剂的制备、表征及氧化脱除苯并噻吩性能

 采用溶胶-凝胶法制备了SiO₂-WO₃催化剂,并采用XRD、FT-IR、BET、TG-DTA等方法对催化剂进行表征。以苯并噻吩(BT)为模型化合物,H₂O₂为氧化剂,考察了催化剂的活性元素、制备方法、n(W)/n(Si)和焙烧温度对其催化氧化脱硫活性的影响。结果表明,W的引入降低了SiO₂的比表面积,SiO₂-WO₃催化剂中W的主物相为WO₃。在以W为活性组元,且n(W)/n(Si)为0.1时,500℃焙烧得到的SiO₂-0.1WO₃催化剂具有最好的催化脱硫活性。在模拟油20 mL、催化剂SiO₂-0.1WO₃用量0.04 g、n(H₂O₂)/n(S)为15.9、乙腈/模拟油体积比0.3、65℃反应60 min的条件下,苯并噻吩模拟油脱硫率可达99.3%。     

Production of olefins from syngas over Al2O3 supported Ni and Cu nano-catalysts

The most important products that can be produced from syngas are methanol, dimethyl ether and light olefins (ethylene and propylene). The light olefins are the most important syngas products, because many of the chemicals are produced from them. The aim of this work was to study the olefins production from syngas over Al₂O₃-supported Ni-Cu nano-catalysts. In addition, the effect of various factors such as catalyst on olefin production and CO conversion has been investigated. The concentration of heavier olefins (C5) was greater than the remaining olefins, since the rate of reactions must be increased to form C1 to C4. In the case of a Ni/Al₂O₃ catalyst, C1 and C4 was initially increased and then decreased with an increase in Ni loading from 0% to 15%.     

Design of Catalyst Support for Deep Hydrodesulfurization of Gas Oil

Abstract

Alumina-silica (Al₂O₃-SiO₂) composite supports were examined to find the optimum state of support (i.e., composition and morphology). SiO₂ content in the Al₂O₃-SiO₂ support induced a shift of the main peak to higher frequency ascribed to an increased amount of Mo₈O₂₆ ^4?. A 75 wt% Al₂O₃-25 wt% SiO₂ support had homogeneously dispersed alumina particles of smaller size with high crystallinity. Hydrodesulfurization (HDS) of straight-run gas oil and its conventionally hydrotreated straight-run gas oil was performed over NiMo sulfides supported on Al₂O₃-SiO₂ composites. The high crystallinity of NMASA2-27 may be related to the high HDS and hydrogenation activity of NiMo sulfides due to its moderate interaction with the alumina surface.     

氧化镁改性微米TS-1催化丙烯环氧化

合成了粒径在1~2 μm的廉价微米TS-1,并经MgO改性,杀灭其上少量的酸中心;采用SEM、XRD、BET对MgO改性前后的TS-1进行了表征,并考察了其在甲醇溶剂体系丙烯环氧化的催化性能。结果表明,TS-1催化剂经MgO改性后,可以显著提高其催化丙烯环氧化反应的环氧丙烷(PO)选择性,减少副反应的发生;在最优化反应条件CH₂O₂ =1.0 mol/L, θ = 60℃, t = 60 min, p_C3↓H6↓ = 0.6 MPa,以及按每1 gTS-1需80 mL CH₃OH的比例下,H₂O₂转化率达到99.5%,环氧丙烷选择性达到96.7%,环氧丙烷收率比未改性的微米TS-1也有明显提高。     

Application of Light Hydrocarbon (C7+) and Biomarker Analyses in Characterizing Oil from Wells in the North and North Central Sinai,Egypt

Abstract

Seven representative oil show samples from wells in the north and north central Sinai have been characterized by means of a variety of organic geochemical techniques (C₇ hydrocarbon and biomarker analyses), to illustrate origin, differences, and similarity among oils. These oils were obtained from Cretaceous and Jurassic reservoirs. The C₇ oil correlation star diagram (OCSD) suggests closely related oils, derived mainly from similar source rocks, while the C₇ oil transformation star diagram (OTSD) and C₇ light hydrocarbon analyses indicate a minor degree of transformation of some oils, as Misri-1, Halal-1, and Nakhl-1 oils were subjected to evaporative fractionation. Moreover, the studied oils show no sign of water washing and biodegradation. Molecular characteristics suggest pre-Tertiary shales and carbonate source rocks, deposited under a saline oxic environment, rich in terrigeneous organic sources with significant bacterial and algal input. Since the studied oils are of mixed marine and terrestrial origin, C₇ signature of these oils is not representative of their origin and should be supported by other geochemical evidence (e.g., biomarkers) to predict their origin.