LTAG技术对催化裂化目的产品的影响

催化裂化轻循环油(LCO)因高芳烃、低十六烷值,性质较差,目前在我国LCO主要用于生产柴油调和组分或直接作为燃料油,无法满足油品升级和目前环保指标的要求。为了更好地适应市场变化,缓解柴油库存压力,洛阳石化采用催化柴油加氢处理-催化裂化组合工艺(LTAG)技术对柴油加氢和II套催化进行了改造。与LTAG技术投用前相比,在大幅压减催化柴油的基础上,目的产品(液化气和汽油)的产品分布和质量得到了改善,催化汽油辛烷值提高,烯烃大幅下降,芳烃含量大幅升高,满足了油品升级和环保指标的要求。此外,通过对比LCO加氢深度对催化裂化反应的影响发现:若想获得低成本、高收率、高辛烷值的汽油,必须合理控制副反原料LCO的加氢深度,即加氢必须保持高的多环芳烃饱和率以及高的单环芳烃选择性,要尽可能将多环芳烃选择性地加氢饱和为单环芳烃。     

提高催化重整氢收率的途径分析

随着加工原油质量变重变劣,且环保要求日趋严格,以及市场对优质汽、柴油需求量的增加,炼油厂需要进一步提高加氢工艺装置的加工能力和深度。催化重整装置的副产氢气可为炼油厂加氢精制、加氢改质、加氢裂化等加氢装置提供氢源。催化重整氢气收率与工艺过程类型、原料组成、催化剂类型和操作参数等有关。催化重整工艺过程类型选用连续再生式重整,氢气收率和氢气纯度均比半再生重整高。选用环烷烃含量高的催化熏整原料,有利于提高重整氢的收率,这是由于产生氢气的环烷脱氢反应发生的越多,氢气收率越高。催化重整催化剂选用高选择性、低积炭的催化剂,有利于提高重整氢收率,并可提高催化剂的选择性和寿命。改善重整过程的操作参数（如适当提高反应温度和降低反应压力等）,可以提高重整氢收率,但是不推荐采用提高空速和降低氢油比的方法来提高氢气收率。此外,实践证实,从重整原料中脱除大部分c。烃（包括环烷烃、苯和己烷）,有利于增加催化重整氢气净收率,同时可以提高汽油收率,增大汽油辛烷值,并降低炼油厂苯的生成。     

FHUDS催化剂在1.20Mt/a柴油加氢装置上的应用

国V柴油质量升级的主要目的是深度降低柴油中的硫含量,进一步提高柴油的十六烷值。对现有的柴油加氢装置进行改造,选用新型加氢催化剂,生产符合国V质量标准的油品是炼油企业应对国V质量升级的有效途径。中国石化长岭分公司1.20Mt/a柴油加氢装置选用FHUDS系列催化剂,设计以巴陵柴油为主,掺炼12.5%焦化柴油,生产满足国V车用柴油标准的调和组分。2017年7月,用纯催化柴油对装置进行了标定。结果表明,在反应器入口温度298℃、反应氢分压4.5MPa、氢油体积比783条件下,其脱硫率达到99.1%,脱氮率达到95.3%,精制柴油十六烷指数提高2.4个单位。改用巴陵柴油做原料,并掺炼部分焦化柴油时,在反应器入口温度340℃、反应氢分压5.3MPa、氢油体积比670的条件下,精制柴油硫含量为3.0μg/g,十六烷值指数为52.3,达到国V车用柴油质量标准要求。     

FHUDS-5/6加氢脱硫催化剂在金陵石化柴油加氢装置上的应用

金陵石化公司Ⅲ套柴油加氢装置设计处理量为250×104t/a,原料由直馏柴油、焦化柴油和催化柴油构成,构成比例为直馏柴油占47.6%、焦化柴油占32.8%、催化柴油占19.6%。为应对油品质量升级的要求,2013年3月,该装置更换由抚顺石油化工研究院研发的超深度加氢脱硫催化剂FHUDS-5及FHUDS-6,连续8d试生产3×104t欧Ⅴ标准柴油。与常规FH-UDS、FHUDS-3催化剂相比,FHUDS-5催化剂的加氢脱硫、脱氮活性明显提高,在相同条件下加工同一原料时,所需反应温度低,具有深度加氢脱硫活性好、装填密度低及氢耗低等特点,尤其适合大分子硫化物的脱除,适宜加工高硫柴油馏分原料,生产超低硫清洁柴油;FHUDS-6催化剂为高活性Mo-Ni型,用于加工处理直柴掺兑焦化汽柴油及催化柴油混合油,或单独处理纯催化柴油时,其反应温度比FHUDS-2催化剂降低约10℃,其深度脱硫活性及十六烷值增幅也明显优于FHUDS-2催化剂。结合生产实际,从参数变化、原料性质、产品性质、物料平衡、产品收率、能耗等方面,分析两种催化剂在欧Ⅴ标准柴油生产中的应用。结果表明,FHUDS-5及FHUDS-6催化剂具备加工欧Ⅴ标准柴油的性能,但装置能耗较高,催化剂失活速率加快,精制柴油收率下降。     

FRIPP柴油深度加氢脱硫技术工业应用

我国国Ⅲ标准柴油要求硫含量小于350μg/g,国Ⅳ标准柴油要求硫含量小于50μg/g。洛阳石化增上的2.6Mt/a柴油加氢装置,采用抚顺石油化工研究院(FRIPP)新开发的FH-UDS催化剂。该催化剂加氢脱硫和加氢脱氮活性高,对原料适用性强,可以在较高空速、较低氢油比条件下加工各类柴油原料,生产硫含量小于350μg/g的柴油产品,若调整工艺条件,亦可生产硫含量小于50μg/g的低硫柴油,是生产低硫柴油的理想催化剂,尤其适合处理以直馏柴油为主,掺炼二次加工柴油的混合原料。洛阳石化2.6Mt/a柴油加氢装置运行结果表明:原料和操作条件达到设计要求;在反应压力为7.55MPa、体积空速为2.42h-1、平均反应温度为365℃、氢油体积比为386.9等工艺条件下,加工焦化柴油、直馏柴油、催化柴油和焦化汽油等混合原料,生产出硫含量小于350μg/g的清洁柴油。     

整体式催化剂上甘油水蒸气重整制氢

为改善甘油重整制氢反应在转化率、氢产率以及抑制积碳方面都与热力学平衡存在较大差距的问题,设计开发了整体式重整催化剂.考察了涂层组分、比例对整体式催化剂理化特性及其在甘油水蒸气重整制氢反应中催化性能的影响.通过考察Ce-Zr物质的量比及La的添加对催化剂活性的影响,确定了Ce-Zr-La物质的量比为1∶1∶1为最优条件.整体式催化剂的活性得到明显改善,在甘油质量分数为10%,空速为3.07,h-1时,在温度考察范围内甘油完全转化为气相产物,氢气选择性递增,并趋于平稳,最高可达90.85%;随着空速增大,甘油质量分数的增加,氢气选择性减小,甘油气相转化率降低,但仍可保持较好的转化效果.     

FHUDS-5/FHUDS-6/FHUDS-8级配催化剂生产国Ⅴ、国Ⅵ柴油应用分析

中国石化金陵分公司2.5Mt/a柴油加氢装置,以常减压柴油、催化柴油和焦化柴油为原料(催化柴油质量分数不超过20%,焦化柴油质量分数不超过15%),采用FHUDS-5/FHUDS-6/FHUDS-8级配催化剂,通过新增第二反应器后,降低反应空速至1.0h~(-1),装置满负荷标定结果表明:FHUDS-6、FHUDS-8催化剂活性较强,装填在反应器上部,有助于多环芳烃的加氢饱和;FHUDS-5催化剂装于二反下床层,充分发挥其在较高温度下的烷基转移超深度脱硫优势,有利于大分子硫化物的脱除;反应系统压降升高,但循环氢压缩机运行稳定,新氢压缩机需要双机运行,需做好管线减震固定措施;在反应器入口温度310℃、反应压力7.4MPa条件下,精制柴油硫含量均低于10mg/kg,闪点高于70℃,凝点低于-4℃,密度平均降低20.5~23.4kg/m~3,均低于845kg/m~3,多环芳烃含量在4%左右,十六烷值为51,满足国Ⅴ、国Ⅵ标准;生产国Ⅴ、国Ⅵ柴油的能耗差异主要在于优化换热流程,提高自发蒸汽数量。     

加氢改质装置深度加氢处理生产国Ⅴ柴油影响因素分析

随着柴油排放标准日益严格,柴油质量升级步伐加快,超低硫清洁柴油需求增加。为了能够及时向市场全面供应符合要求的产品柴油,济南石化于2015年10月对800kt/a柴油加氢改质装置进行了国Ⅴ标准柴油的试生产。根据原料性质、工艺参数、产品质量、物料平衡及产品分布情况,对柴油产品硫含量的影响因素,如原料性质、加氢反应温度、循环氢硫化氢含量等进行了逐一分析。调整期间,采取优化原料、提高加氢反应温度等措施,通过标定最终得出结论:装置在现有催化剂和允许的操作条件下,可以生产国Ⅳ标准柴油,但无法生产硫含量小于10μg/g的国V标准柴油。原因在于:催化剂装填量偏小;循环氢中的硫化氢含量较高;高压换热器存在微量泄漏现象。针对这些原因,提出改造建议:增上一台加氢反应器,更换新型催化剂,增上一套循环氢脱硫设施,更新加氢反应换热器。计划于下次大检修时实施,以确保提供国Ⅴ标准柴油。     

MoO3催化剂上苯酚加氢脱氧制取芳烃研究

以(NH_4)_6Mo_7O_(24)·4H_2O为前驱体通过简单的焙烧方法制备非负载型MoO_3催化剂,通过低温N_2吸附、X射线衍射(XRD)、X射线光电子能谱(XPS)和H_2程序升温还原(H_2-TPR)技术对催化剂特性进行表征,以苯酚为模型化合物进行加氢脱氧实验制备以苯为主要产物的芳烃化学品。重点考察反应温度、反应时间、反应气组成等参数对苯酚转化率、目标产物苯选择性的影响,并就氧化钼催化加氢脱氧反应机制及催化剂的可重复使用性能进行讨论与考察。实验结果表明,在340℃、0.5 MPa H_2与3.0 MPa N_2混合气氛的优化工况下,苯酚的转化率达到98.1%,产物苯选择性达到99.5%。MoO_3催化材料中的氧缺陷位是催化苯酚分子中C_(AR)—OH键直接氢解生成芳烃苯的主要活性位。此外,MoO_3重复使用3次后催化活性仍无明显下降,表明该催化剂的加氢脱氧催化活性具有良好的稳定性。     

碳二加氢精制催化剂研究进展

催化选择加氢工艺技术是提纯裂解烯烃最普遍的方法,而碳二加氢精制催化剂是乙烯分离工艺流程的关键技术之一。介绍了国内外碳二选择性加氢精制催化剂的发展现状,包括催化剂的制备工艺、催化剂的载体、活性组分及助催化剂的进展情况。对碳二馏分选择性加氢反应机理进行了探讨,深入分析了空速、反应温度、一氧化碳浓度及氢炔比等因素对催化剂使用性能的影响。提出了碳二加氢精制催化剂的发展方向,一是加强对蛋壳型催化剂的研究,将活性组分钯分布在载体表面壳层,使钯层更薄,提高钯的利用率,使之表现出更好的碳二加氢反应活性和乙烯选择性;二是通过添加其他组分对钯基催化剂进行改性,发展多组分钯基催化剂,以提高乙烯选择性、减少绿油生成量和延长催化剂运行周期。因此,开发出高活性、高乙烯选择性、高空速、低绿油生成量、再生性能更好的非贵金属催化剂具有现实意义。     

Catalytic performance of Pd–Ni bimetallic catalyst for glycerol hydrogenolysis

Catalytic conversion of glycerol from biodiesel production to value-added chemicals and fuels is actually of great interest for industrial chemical research. Bimetallic catalysts are confirmed superior to monometallic catalysts in terms of catalytic activity and selectivity for glycerol hydrogenolysis. Accordingly, a series of Pd–M (M = Fe, Co, Ni, Cu, Zn) bimetallic catalysts were prepared in this work via coprecipitation to investigate the promoting effect of Pd. The relationship between the catalytic performance and metal-support interaction was also discussed. Through the catalyst screening, Pd–Ni bimetallic catalyst exhibited moderate activity and the highest selectivity towards ethylene glycol. At 493 K and hydrogen pressure of 6.0 MPa, the glycerol conversion and selectivity of ethylene glycol reached 89% and 22% respectively. XRD and TEM patterns showed that the Pd nanoparticles with an average size of ∼4 nm were uniformly dispersed in the supports. H₂-TPR revealed that the reduction temperatures of metal oxides were significantly decreased by the introduction of Pd component. XPS curves indicated that unique performance of the Pd–Ni bimetallic catalyst might be attributed to the formation of Pd–Ni alloy. And the required metal-support interaction was assumed responsible for the cleavage of C–C bond and generation of ethylene glycol. In the end, hydrogenolysis reactions for the main products of glycerol conversion were carried out over Pd–Ni catalyst to explore the possible reaction pathways for glycerol hydrogenolysis.     

Biodiesel resources and production technologies – A review

The environmental concern and availability of fuels are greatly affecting the trends of fuels for transportation vehicles. Biodiesel is one of the options as alternative transport fuel. This can be produced from straight vegetable oils (SVOs), oils extracted from various plant species and animal fats. Amongst many resources, availability and cost economy are the major factors affecting the large scale production of the biodiesels. The transesterification is one of the production processes for biodiesel, but incomplete esterification of all fatty acids in the starting material, lengthy purification methods such as water washing, relatively long reaction times, contamination and separation difficulties associated with co-production of glycerol and saponification of the starting material under certain reaction conditions are still being major challenges in the biodiesel production. Technological advancement and enhanced production methods are the demand of present time for large scale and sustainable production of biodiesel. In the present paper, comprehensive review on its production process, feed stock and its applications have been made. From many case studies it was concluded that engine performance with B20 biodiesel blends, and mineral diesel were found comparable.     

甘油水蒸汽重整制氢研究进展

随着生物柴油的规模化发展,其副产物甘油的高效利用成为影响生物柴油成本和新一代化学品平台工艺开发的重要问题。将甘油转化为氢气符合未来能源对可再生和CO2净零排放的要求,正受到新能源研究领域的密切关注。综述了甘油水蒸汽重整制氢的热力学、反应机理和催化剂的研究现状,对甘油水蒸汽重整未来的发展进行了评述。     

Critical review on the current scenario and significance of crude glycerol resulting from biodiesel industry towards more sustainable renewable energy industry

Biodiesel production through transesterification of vegetable oils and animal fats is rapidly increasing due to strong governmental policies and incentives. However, corresponding increase in the production of crude glycerol causes mixed effects. Sustainable biodiesel production requires optimization of its production process and drastic increase in the utilization of glycerol. High biodiesel yields and low environmental impacts, with respect to needless waste streams are mandatory. As such, upgrading of crude glycerol to highly pure glycerol and subsequent utilization of the product in producing value-added products are emerging research areas. International crude glycerol market is still at an early and very unstable stage. Globally, future conditions for an international market will largely be decided by supply and demand of glycerol for its utilization in conventional and newly developed industries. This paper highlights the current scenario on glycerol production from biodiesel industry, its global market and its new emerging outlets as commodity chemicals.     

Biodiesel purification using micro and ultrafiltration membranes

Biodiesel is an environmental-friendly fuel that can replace petroleum diesel. However, after transesterification reaction of vegetable oils, the obtained crude biodiesel must be purified. The commonly applied purification step is water washing. This step is a concern in biodiesel production, since large quantities of clean water are used, generating a wastewater stream to be further treated. Here we propose the application of micro and ultrafiltration processes to purify crude biodiesel. Crude biodiesel was filtrated in a dead-end process at different transmembrane pressures and using membranes of different pore sizes. Flux results showed that greater transmembrane pressures, as well as greater pore sizes, enable greater fluxes. Density, viscosity and acid values of purified biodiesel (washed and filtrated) are in accordance to the international legislation for biodiesel quality. Both processes (water washing and membrane separation) were able to reduce the amount of soap detected in crude biodiesel. However, the proposed microfiltration membranes were not efficient as the washing method to reduce the free glycerol content. The ultrafiltration membrane of 30 kDa was also not able to produce a purified biodiesel according to the international legislation for free glycerol content. Between the analyzed membranes, the glycerol content limit (less than 0.02 wt%) was achieved only with the ultrafiltration membrane of 10 kDa. Water addition in the crude biodiesel improved the glycerol removal by membrane filtration. The obtained results showed that the membrane separation process is a suitable alternative for biodiesel purification.     

The influence of impurities on the acid-catalyzed reaction of glycerol with acetone

The acid-catalyzed reaction of glycerol with acetone was studied in the presence of impurities that might be present in the crude glycerin of biodiesel production. These are mainly methanol, water and sodium chloride, in different amounts. The results indicated that methanol has minor effect on the glycerol conversion, whereas the concomitant addition of water and sodium chloride produces a drastic decrease of the conversion. The nature of the acid catalyst also affects the conversion in the presence of impurities. Amberlyst-15™ acid resin is more sensible to the water content than zeolite Beta. The results of the glycerol adulteration with different contaminants were compared with the reaction using a crude glycerin from a Brazilian biodiesel industrial plant.     

Dimethyl carbonate mediated production of biodiesel at different reaction temperatures

Methanol was replaced by dimethyl carbonate for biodiesel production. In the process, fatty acid methyl ester (FAME) was produced through transesterification of soybean oil with dimethyl carbonate (DMC) using potassium methoxide as a catalyst. This method produced a more attractive by-product, glycerol carbonate (GC). Factors affecting the reaction such as vegetable oil to DMC molar ratio, catalyst concentration, reaction time and reaction temperature were optimized. Triglyceride conversion of 95.8% was obtained at the optimized condition. This process provided an insight into the reactivity of DMC at different temperature. Co-production of FAME and glycerol carbonate (GC) proceeded through carboxymethylation reaction because methoxyl group and carbonyl group are generated which subsequently attacked the carbonyl moiety in glyceride molecules to form the required products.     

Hydrogen and syngas production from glycerol through microwave plasma gasification

Glycerol which is a byproduct of biodiesel production is considered as a potential feedstock for syngas production with the increase of biodiesel demand. In this study, the characteristics of glycerol gasification under a microwave plasma torch with varying oxygen and steam supply conditions were investigated. The experimental results demonstrated that the gasification efficiency and syngas heating value increased with the supplied microwave power while the increase of oxygen and steam led to a lower gasification performance. In order to achieve high carbon conversion and cold gas efficiency in the microwave plasma gasification of glycerol, the O₂/fuel ratio should be maintained at 0–0.4. It was revealed that the fuel droplet size and the mixing effect and retention time inside the plasma flames are critical factors that influence the product gas yield and gasification efficiency. This study verified that syngas with a high content of H₂ and CO could be effectively produced from glycerol through microwave plasma gasification.     

Microbial hydrogen production by bioconversion of crude glycerol: A review

Hydrogen is a clean source of energy with no harmful byproducts produced during its combustion. Bioconversion of different organic waste materials to hydrogen is a sustainable technology for hydrogen production and it has been investigated by several researchers. Crude glycerol generated during biodiesel manufacturing process can also be used as a feedstock for hydrogen production using microbial processes. The possibility of using crude glycerol as a feedstock for biohydrogen production has been reviewed in this article. A review of recent global biodiesel and crude glycerol production and their future market potential has also been carried out. Similarly, different technical constraints of crude glycerol bioconversion have been elaborately discussed and some strategies for improved hydrogen yield have also been proposed. It has been underlined that use of crude glycerol from biodiesel processing plants for hydrogen production has many advantages over the use of other organic wastes as substrate. Most importantly, it will give direct economic benefit to biodiesel manufacturing industries, which in turn will help in increasing biofuel production and it will partially replace harmful fossil fuels with biofuels. However, different impurities present in crude glycerol are known to inhibit microbial growth. Hence, suitable pretreatment of crude glycerol is recommended for maximum hydrogen yield. Similarly, by using suitable bioreactor system and adopting continuous mode of operation, further investigation of hydrogen production using crude glycerol as a substrate should be undertaken. Furthermore, isolation of more productive strains as well as development of engineered microorganism with enhanced hydrogen production potential is recommended. Strategies for application of co-culture of suitable microorganisms as inoculum for crude glycerol bioconversion and improved hydrogen production have also been proposed.     

Scope and opportunities of using glycerol as an energy source

Biodiesel is a promising fuel for diesel engines in wake of its renewable nature and environmental benefits. Biodiesel can be produced by different pathways; however, glycerol (or glycerin, glycerin) is a valuable by-product which is formed during this process. As mandates are being enforced by different government worlds over, the demand of biodiesel is likely to go up. With increased demand and production of biodiesel, significant quantity of glycerol shall be available. There is an urgent need to find alternative application area of glycerol so that viability of biodiesel industry can be sustained.In the present study, the focus has been made on the various application areas of using surplus glycerol from biodiesel industries to make them more financially attractive. Amongst the different pathways of using glycerol as a source of energy; direct combustion, mixing with agricultural solid wastes and then burning, blending directly or indirectly with other fuels, hydrogen and hydrocarbon production from glycerol, etherification, etc. are prominent one. The requirement, advantages and limitations of each approach have also been evaluated in the study. Combustion of glycerol if not done properly would result in formation of acrolien which is highly toxic in nature and efforts should be made to use glycerol indirectly to produce energy (i.e. all the pathways expect the direct combustion and the solid fuel method). The production of hydrogen from glycerol via APR appears to be the best solution to the disposal problem since the hydrogen yield via APR is highest. Moreover the process occurs at lower pressure and temperature when compared to steam reforming, and it is a single step process. Etherification, tri-acetylisation, and blending have been found to be useful for improving the performance of automotives by facilitating proper and smooth combustion of fuel.