重整进料硫含量超标的原因及应对措施

分析了连续重整装置中硫含量超标的原因,认为是罐区精制石脑油中溶解的氧与重整原料预处理高分油中的H2S生成了不能靠蒸发汽提方式脱除的游离态硫导致的,通过实行停重整注硫泵、提高重整原料预处理反应温度等措施后,重整进料硫含量恢复正常。     

1．2Mt／a重整装置进料硫含量超标原因与对策

对1．2Mt/a连续重整装置出现的重整进料硫含量超标的异常情况进行了分析,认为预加氢反应进料、出料换热器内漏、重整进料硫化剂注入过量、罐区来精制油中溶解氧与高分出料中的H2S反应生成不易汽提脱除的元素硫是硫含量超标的原因,通过采取检修换热器、暂停注硫泵、停止罐区来精制油进汽提塔等措施后,重整进料的硫含量达到了指标要求。     

石脑油加工情况及优化

介绍了某石化石脑油加工情况及重整装置运行情况,通过各项数据分析出问题点,并采取柴油加氢汽提塔抽出不稳定石脑油,高低油硫石脑油分储分炼,双塔工况等手段对部分问题进行了缓解,并提出后续的优化思路.     

预加氢装置常见问题分析及解决措施

针对连续重整装置预加氢单元精制油硫含量偏高的现象,从原料组分、反应深度、汽提塔运行状况等方面进行了分析。结合实际案例,得出精制油硫含量偏高的原因为汽提塔回流过大,导致部分溶解有硫化氢的轻组分进入塔底。此外,分别对预加氢反应系统和汽提塔塔顶系统常见的腐蚀问题提出了相应的防护措施。     

重石脑油脱硫技术应用

为保证炼油厂中压加氢裂化装置所产重石脑油的总硫含量符合重整装置直接进料的标准,在加氢裂化装置后部设置精脱硫反应装置,以脱除重石脑油可能携带的微量硫。通过技术选择,采用某公司的Zn系催化剂,在设计的操作条件下,满足进料要求的原料通过反应器后,产品质量能满足后续装置直接进料的要求。     

连续重整装置进料硫含量的影响及控制

以连续重整装置工艺技术为基础,借鉴国内炼化企业运行经验,浅析硫含量对连续重整装置运行的影响。连续重整装置硫含量超标会导致重整催化剂中毒,活性下降,重整产品质量降低。同时,硫含量不能过低,以防止重整装置内加热炉、反应器内壁等高温部位结焦。通过加强进料化验分析、严格控制石脑油加氢单元操作参数、重整单元降温处理等方法来控制重整进料硫含量,以保证重整装置长周期运行。     

催化剂级配技术在300万t/a柴油加氢裂化增产化工原料装置中的应用

为了提高产品质量、降低柴汽比、增产化工原料,将350万t/a柴油加氢精制装置改造为300万t/a柴油加氢裂化装置,采用A公司HDS催化剂体相催化剂及加氢裂化催化剂级配来实现柴油加氢超深度脱硫时增产化工原料,装置改造中反应系统改动较少,主要集中在分馏部分。标定数据表明,加工直馏柴油工况,反应压力7. 35 MPa,催化剂床层平均温度为340. 2℃,重石脑油硫含量0. 1μg/g,氮含量0. 3μg/g,重石脑油收率达到17. 82%,喷气燃料冰点为-55. 9℃,烟点为28. 5 mm,精制柴油硫含量5. 5μg/g,多环芳烃0. 8%,达到国Ⅵ柴油标准。在多掺炼20%催化柴油工况,床层平均温度提高11℃,重石脑油收率达到12. 98%,重石脑油质量可满足重整料要求,精制柴油达到国Ⅵ柴油标准。     

连续重整装置液化气硫含量高原因分析及对策

在连续重整装置运行期间,产生的液化气一旦硫含量过高,不仅将导致副产物质量不佳,还将影响装置整体运行效果。以某项目为例,对液化气硫含量高的原因展开分析,在确定液化气硫来源的基础上,结合工艺流程判断影响硫含量的因素,逐一完成进料硫含量、设备运行参数、换热器故障等原因排查,最终确定液化气硫含量超标与汽提塔换热器内漏有关,通过修复内漏和合理注入缓蚀剂成功降低了液化气硫含量,为装置可靠运行提供保障。     

连续重整预加氢系统压降增大处理措施

预加氢是对粗石脑油进行预处理,给重整反应提供合格精制油。随着运行时间延长,预加氢系统压降过大,这成为连续重整装置高负荷生产的瓶颈。针对这一问题对反应器床层上部催化剂进行了过筛处理,加热炉炉管进行爆破吹扫等一系列的处理。结果表明:预加氢反应系统压降大大降低,预加氢燃料气用量大幅度降低;同时,装置加工量大幅度上升,保证了下游重整装置有充足的精制石脑油。     

高硫原料油对乙烯装置的影响分析及对策

针对乙烯装置裂解原料石脑油中硫含量偏高的情况,分析了使用高硫油在工艺、设备和安全环境方面对乙烯装置的影响,并从实际出发,提出了选择合理的原油炼制方案来降低石脑油中硫含量,从根本上解决硫含量偏高的问题。另外,还可以从改进工艺操作、加强监测、对设备材料进行升级处理等角度考虑如何减少高硫原料油对乙烯装置的影响。     

重整反应苛刻度低原因分析及处理措施

针对金陵石化I重整装置2016年2月出现的脱庚烷塔底物料中非芳含量上升、抽提原料中非芳含量上升、反应总温降下降以及单位产氢量下降等反应苛刻度低的问题进行详细分析,总结出可能引起反应苛刻度低的四个方面条件:I重整进出物料换热器内漏、原料性质、操作条件及催化剂性质,并分别对四个方面的条件进行详细的数据对比分析,最后得出本次I重整装置反应苛刻的低的主要原因为增加了S含量高达(4~6)×10-6的II加氢裂化装置重石掺炼量,致使重整催化剂出现轻微的S中毒,加快了催化剂积碳速率,且因I重整装置扩容改造后未增加催化剂再生能力,再生能力不足直接导致待生催化剂中C含量高达6.66%,从而使重整催化剂金属活性降低,直接降低了催化剂烷烃脱氢环化性能,使I重整反应苛刻度下降,脱庚烷塔底C8+物料及抽提进料中非芳含量明显升高。     

重整装置原料预处理部分的优化设计

重整原料预处理是催化重整装置的一个重要组成部分。通过对先加氢后分馏和先分馏后加氢两种预处理工艺流程的对比，推荐采用先加氢后分馏的工艺流程，以60万t／a连续重整装置为例，对经过预加氢处理后的石脑油，采用先汽提后分馏和“二塔合一”工艺流程的主要设备、投资、能耗等进行了对比，推荐采用先汽提后分馏工艺流程设计方案。     

石脑油加氢单元进料水冲击的现象分析及处理

文章通过对国产化催化重整联合装置石脑油加氢单元进料水冲击造成重整进料硫、氮含量超标的现象进行了分析,指出了原料带水对石脑油加氢催化剂活性及系统操作的影响,此时可通过加强脱水、提高反应温度和压力以及降低空速等方法进行处理。     

石脑油预加氢装置运行状况分析及防护措施

介绍了中国石化西安石化分公司300 kt/a石脑油加氢装置运行状况,针对反应器压力降升高、石脑油进料/反应产物换热器内漏导致精制油硫含量超标原因进行系统分析,通过检测、比较各换热器低硫端油样中的总硫含量判断换热器的内漏位置,指出原料油携带重质馏分油及腐蚀残渣是反应器压力降升高的重要因素,垢下腐蚀和H2S-HCl-H2O-NH3酸性腐蚀是换热器管束减薄甚至穿孔的主要原因。提出进料线设置过滤器、增设1台高温脱氯器、优化注水部位及注水量、石油脑油进料直供及材质合适材质等措施,以保证装置长周期运行。     

Thermal Integration of Sulfuric Acid and Continuous Catalyst Regeneration of Naphtha Reforming Plants

An optimal reactor design is proposed that simultaneously improves the naphtha reforming reactor performance and increases sulfur trioxide production. In this new configuration, the naphtha reforming process as an endothermic reaction is coupled with the oxidation reaction of sulfur dioxide, which is an exothermic reaction. The differential evolution optimization technique is applied to maximize the produced amounts and yields of aromatics and hydrogen. The results obtained with the optimized thermally coupled reactor are compared with those of the conventional and thermally coupled reactors, proving the superiority of the proposed configuration.     

MOLECULAR MODELING AND OPTIMIZATION FOR CATALYTIC REFORMING

In this paper, molecular modeling and optimization for the naphtha catalytic reforming process is studied. The catalytic reforming process is for producing high octane number gasoline by reforming reactions in three sequencing fixed bed reactors. Feed naphtha coming from an atmospheric distillation unit consisted of molecules from C5 to C10 including paraffin, iso-paraffin, naphthene, and aromatic. The molecular reaction network consisted of paraffin cracking, naphthene side-chain cracking, aromatic side-chain cracking, ring opening, ring closure, paraffin isomerization, dehydrogenation, and hydrogenation. A molecular model for catalytic reforming was built. On the basis of the simulation model, a process optimization was performed for feed temperature and pressure under constraints such as benzene content, aromatic content, and RON (Research Octane Number) limitations. High RON was contrasted to low benzene and aromatic content requirements. By optimizing and controlling the reaction pathway, we can obtain a final product with the highest profit and appropriate benzene and aromatic contents and RON value. This example shows significant benefits from applying molecular modeling to optimization in the process level. Since gasoline production is related to many different processes such as reforming, FCC, isomerization, alkylation, and so on, more benefits can be obtained by applying molecular modeling to plant-wide optimization.     

MOLECULAR MODELING AND OPTIMIZATION FOR CATALYTIC REFORMING

In this paper, molecular modeling and optimization for the naphtha catalytic reforming process is studied. The catalytic reforming process is for producing high octane number gasoline by reforming reactions in three sequencing fixed bed reactors. Feed naphtha coming from an atmospheric distillation unit consisted of molecules from C5 to C10 including paraffin, iso-paraffin, naphthene, and aromatic. The molecular reaction network consisted of paraffin cracking, naphthene side-chain cracking, aromatic side-chain cracking, ring opening, ring closure, paraffin isomerization, dehydrogenation, and hydrogenation. A molecular model for catalytic reforming was built. On the basis of the simulation model, a process optimization was performed for feed temperature and pressure under constraints such as benzene content, aromatic content, and RON (Research Octane Number) limitations. High RON was contrasted to low benzene and aromatic content requirements. By optimizing and controlling the reaction pathway, we can obtain a final product with the highest profit and appropriate benzene and aromatic contents and RON value. This example shows significant benefits from applying molecular modeling to optimization in the process level. Since gasoline production is related to many different processes such as reforming, FCC, isomerization, alkylation, and so on, more benefits can be obtained by applying molecular modeling to plant-wide optimization.     

Simulation of a Commercial Semiregenerative Reforming Plant Using Feedstocks with and without Benzene Precursors

This paper describes the use of kinetic and reactor modeling to simulate the behavior of a commercial semi‐regenerative reforming unit when two feedstocks (with and without benzene precursors) are employed. The feed without benzene precursors was prepared by fractionation of a typical reforming feed. A cut point of 88 °C was selected because most of the C₅–C₆ light naphtha is excluded. This cut point was not deep enough to remove the main benzene precursor, cyclohexane, but other precursors, i.e. methylcyclopentane and n‐hexane, were almost totally eliminated. It was decided not to increase this cut point value beyond 88 °C because this would reduce the flowrate of the feedstock to the reforming unit, which is not convenient due to refineries gasoline production policies. It has been shown that naphtha fractionation is a very good method for reducing the content of benzene precursors in reforming feedstocks, and consequently an important decrease in reformate benzene concentration can be achieved.     

Industrial application of an extended fully thermally coupled distillation column to BTX separation in a naphtha reforming plant

Aromatic compounds are yielded from naphtha reforming in a petrochemical plant, and the products are separated with binary distillation columns for benzene, toluene, xylene and heavy components in sequence. In this study, the first three columns of the fractionation process in the naphtha reforming unit are replaced with an extended fully thermally coupled distillation column (EFTCDC) also known as the extended Petlyuk column. An industrial-sized application of the EFTCDC is examined to compare the performance of the column with a conventional system. From a structural design giving the optimum structure of the column, a practical column structure is derived and used in the HYSYS simulation to find the optimal operation condition for a given set of product specifications. The EFTCDC gives an energy saving of 9.7% over a conventional three-column process. In addition, it is proved that the design procedure is good for an industrial process of 18 components.     

神府煤液化油石脑油馏分重整生产芳烃的研究

由于煤液化油石脑油馏分(200℃)中芳烃潜含量较高,利用煤液化油石脑油馏分为原料,进行加氢精制,将原料中的硫氮含量降至1 mg/kg左右,满足重整进料要求,然后在小型固定床连续反应器上进行加氢重整生产芳烃试验。着重考察重整反应前、后族组成的变化及主要芳烃化合物的产率。结果表明,加氢重整过程中发生正构烷烃异构化反应;环烷烃主要发生脱氢芳构化反应转化为芳香烃;煤液化油石脑油馏分适宜进行催化重整,C_1~C_4烃气产率6.03%,氢气产率3.60%;重整后,芳烃含量达83.20%,其中C_6~C_8芳烃含量61.03%,是提取BTX的良好原料。石脑油的馏程对芳烃的组成和产率有一定影响,适宜的馏程为60~160℃。