Petroleum Refining Processes
Desulphurisation
Sulphur occurs in crude oils combined in a variety of ways from the simplest compound H2S to complex ring structures H2S is produced during distillation of the crude oil by decomposition of higher boiling sulphur compounds and appears in the LPG from which it must be removed because of its poisonous and corrosive nature This is done by counter current washing with an amine (egdiethanolamine) the H2S being removed for sulphur recovery by heating the amine solution in a separate vessel thus regenerating the amine for recycle to the washing stage Mercaptans can be considered derivatives of H2S in which one hydrogen atom is replace by a carbon hydrogen group and share some of its unpleasant properties of bad smell and corrosivity Those mercaptans boiling below about 80℃ are readily dissolved in alkaline solutions but the solubility decreases rapidly above that temperature For LPG and light gasolines therefore the mercaptans can be removed by counter current washing with caustic soda solution
The UOP Merox process uses caustic soda to extract the mercaptans which are then oxidised with air to disulphides and the caustic soda regenerated for further use The oxidation step is assisted by a metal complex catalyst dissolved in the caustic soda
The process can be represented as follow
4C2H5SH+4NaOH 4C2H5SNa+2H2O +2H2O
+O2
2C2H5S—SC2H5+4NaOH
The disulphides are not soluble in caustic soda and form an oil layer which can be removed
Mercaptans in fraction boiling between80℃ and 250℃ cannot be oxidised to disulphides in the Merox solution with air The disulphideswhich are noncorrosive and have little smell remain dissolved in the oil so that no actual desulphurisation has been achived but the products have been sweetened Another process for the oxidation of mercaptans uses copper chloride as a catalyst Both processes can be used in the production of aviation jet fuels
As the cuts taken from crude oil increase in boiling point it is found that the sulphur increases In the 250350℃ range which is used for both diesel fuel and domestic centralheating fuel the sulphur content is about 1 per cent weight from most Middle East crudes When this material is burnt the sulphur is oxidised to SO2 which being easily oxidised to sulphuric acid causes atmospheric pollution and corrosion of metals The sulphur cannot be treated by the methods previously outlined as it is mainly combined with carbon and hydrogen in forms much more complicated than the simple mercaptans These complex compounds have to be broken down to get at the sulphur which is done by passing the oil together with hydrogen at high temperature (320420℃) and high pressure (2570 bar) over a catalyst containing cobalt and molybdenum oxides on an alumina base made in the form of small pellets or extrudates The reaction is easier and the catalyst life better when the ratio of hydrogen to feed is several times higher than that necessary to complete the reaction chemically Under these conditions the sulphur compounds decompose and the sulphur combines with the hydrogen to give H2S Almost all of the sulphur compounds can be decomposed in this way without significantly affecting the remaining hydrocarbons
This process of desulphurisation also called hydrofining is effective in attacking all forms of sulphur compounds and can be used to treat any part of crude oil
In principle the equipment used for all feeds is basically simlar and will contain means for carrying out the following steps
1 Supplythe feed and hydrogen to the reactor at the correct temperature and pressure
2 Cool the reactor product to condense the oil and allow the separation of the excess hydrogen so that it can be recycled to the reactor
3 Remove the H2S and small quantity (23 per cent) of lowboiling hydrocarbons producted in the reaction
A pump takes the feed and raises it to the repuired pressure and passes it through tubes in a furnace where it is heated to the required temperature before being mixed with the hydrogen and passing into the reactor The reactor product is cooled partially by the fresh feed in a heat exchanger to save fuel and partially by water in another heat exchanger Excess hydrogen is separated from the condensed oil in a drum and recirculated back to the reactor by a compressor together with fresh hydrogen to replace the amount consumed in the reaction The liquid from the drum is passed into a distillation column where the H2S and lowboiling breakdown products are removed and the desulphurised oil taken from the bottom of the column
Much of the crude oil boiling above 350℃ is used to make heavy fuel oil for powerstations ships and large industrial plants and can have a sulphur content of 254 per cent weight from most Middle East crudes Buring this material releases SO2 and very high chimneys have to be used (a number in the 500600 foot range have been built one of 800 feet in the USA) so that the SO2 can be dispered widely in the atmosphere thus avoiding localised pollution The ideal solution would be to desulphurise all parts of the crude oil Unfortunately although the desulphurisation of distillates boiling up to about 550℃ cab be relatively easily accomplished the treatment of heavy crudeoil residues poses many difficult problems With increasing boilingpoint the difficulty of desulphurisation increases and also the proportion of molecules containing sulphur becomes high (possibly up to 50 per cent) which means that a high proportion of the molecules present must be decomposed Trace metals in the oil tend to deactivate the most effective desulphurisation catalysts and high pressures (up to 170 bar) must bs used All these factors result in high costs for fueloil desulphurisation Also recent developments in the crudeoil sopply situation worldwide have placed a stong emphasis on energy conservation Consequently fuel intensive processes would be employed only as alast resort when alternative means of miniming pollution are not viable
In a refinery where desulphurisation is used extensively the production of H2S can easily reach 100 tonnes per day Although the H2S could be burnt to SO2 and vented from all stacksit is very undesirable because of the atmospheric pollution caused and additional plant is instslled to recover the sulphur The H2S is burnt to SO2 with the oxygen supply limited so that about onethirt of the H2S burns This gives a mixture of twothirds H2S and onethird SO2 which will combine to form sulphur and water
2H2S+SO23S+2H2O
The sulphur is collected and is usually sold to chemical companies mainly for the manufacture of sulphuricacid
Thermal Cracking
When hydrocarbons are heated to temperatures exceeding about 450℃ they begin to decompose The large molecules breaking or cracking into smaller ones Paraffins are the most easily cracked followed by naphthenes aromatics being extremely refractory At one time thermalcracking processes were widely used to improve the octane number of naphthas or to produce gasoline and gas oil from heavy fractions The quality of the gasoline from the thermal cracking of naphtha is not high enough for present motor gasolines and the process has fallen out of use The products from heavy oil cracking requirements and while at present the process is little used it could be of interest should conversion of heavy distillates (up to 550℃) to gas oils be required One thermalcracking process presently in common use is visbreaking which is the thermalcracking of viscous crudeoil residues to reduce their viscousity by breaking down the large complex molecules to smaller onesA satisfactory fuel oil can them be made without the necessity of using gas oils or kerosine to blend with the viscous residue
Another thermalcracking process presently employed is Delayed Coking which is normally applied toatmospheric or vacuum residues from low sulphur crudes for the production of electrode grade coke (used mostly in aluminium production) The residue is heated to about 500℃ and passed to the bottom of a large drum where the cracking reaction proceeds which breaks down the highboiling materials The lower boiling materials formed vaporise at the high temperature in the drum and pass out of the top to the fractionation system where they are separated into gas gasoline and gas oil and leave behind in the drum a porous mass of coke When the drum is full of coke the feed is switched to another drum which is filled while the full one is steamedout and the coke removed As in the thermalcracking process the liquid products require hydrogenation for use as naphtha or gas oil
Catalytic Cracking
Thermal cracking of heavy distillates for gasoline production is not selective and produces substantial quantities of gas and fuel oil together with the gasoline which is also not of very good quality About thirty years ago it was found that fuller’s earth and simillar materials could act as cracking catalysts and give a good yield of high octane number gasline (catalytic cracking) Unfortunately the fuller’s earth became quickly covered in carbon and no longer acted as a catalyst was returned to its previous activity and thus to operate the process continuously it was necessary to devise methods of alternatively using and regenerating the catalyst continuously on a large scale
One of the most successful methods of achieving this depends on the use of fluidisation When a gas is passed up through a bed of fine power the behaviour of the power depends on the velocity of the gas If it is high (about 1 msec) the particles are moved about by the gas and the bed of power acts like a fluid and can be transported find its own level ect just like a liquid By using this property the catalyst in power form can be circulated continuously between a reaction stage and a regeneration stage
The reactor and regenerator vessels are each designed so that the upward vapour velocity is sufficient to fluidise the catalyst The oil feed (normally boiling 350550℃) meets hot (620740℃) regenerated catalyst which is substantially free of carbon and the vaporised oil and catalyst pass through a transfer line to the reactor where the catalyst forms a fluidised bed The cracking reaction proceeds as soon as catalyst meets the oil and is completed within the reactor at 480540℃ depositing carbon on the catalyst The spent catalyst is steam stripped to remove entrained hydrocarbons and returned to the regenerator where air is used to burn the carbon from the catalyst The oil products leave the reactor via cyclones to reduce catalyst entrainment and are separated into fuel gas C3C4 gasoline and gas oils The gasoline octane number can be as high as 95
The catalyst loses activity as a result of hydrothermal deactivation and the accumulation of metals from the feed which can contain up to 1 ppm of vanadium plus nickel Catalyst activity is maintained by continuous sddition oof fresh catalyst and withdrawal of equilibrium catalyst to maintain a constant inventory
In addition to straightrun and vacuum gas oils coker gas oiletc the feed to a catalytic cracker can include atmospheric residue provided the metals content is low enough The Kellogg heavy oil cracking (HOC) process is designed for high metals content atmospheric residue
Great improvement have been made in the manufacture of catalysts which now incorporate molecular sieve materials (zeolite) and have a very high activity It has been found that the long residence time of the vapours in the reactor gives rise to secondary reactions which reduce the selectivity of the conversion to gasoline and produce more gas and coke New designs dispese with the fluid bed in the reactor and carry out the reaction in the transfer line the oil and catalyst are quickly separated at the end of the transfer line for instance in a cyclone and the catalyst drops into a stripper as previously to the remove entrained hydrocarbons before transfer to the regenerator This is called Short Contact Time (SCT) cracking and has markedly improved the yield of gasoline obtainable in the process
Hydrocracking
As hydrocarbons increase in the number of carbonatoms they contain so there is a decrease in the ratio of the number of hydrogen atoms per carbon atom eg methane CH4 has a ratio of 4 pentane C5H12 has a ratio of 24 decane C10H22 has a ratio of 22 If we wish to produce lowboiling hydrocarbons (eg gasoline containing 510 carbon atoms) from highboiling hydrocarbons containing say 20 carbon atoms we must find some means of increasing the ratio of hydrogen to carbon In thermal cracking olefines (which have a lower hydrogencarbon ratio than paraffins) are produced and also carbon eliminated by deposition in the catalyst The alternative approach is to add hydrogen and this is done in the hydrocracking process by cracking at a very high pressure in hydrogen
This process which is very flexible and can produce high yields of either gasoline or gas oil from wax distillaate or gasoline from gas oil operates at pressures of 150170 bar and temperatures of around 430℃ Reactors capable of withstanding these severe conditions may be 150200 mm thick and pose many difficult engineering problems in design and construction Hydrogen requirements for hydrocracking are very high up to about 300 m3 per m3 of oil processsd which is far in excess of that available from catalytic reformers so that a large hydrogen production plant must be built to supply the hydrocracker
When designed to produce gas oil a hydrocracker will use one reactor and the basicflow diagram appears very similar to a hydrofiner but two reactors containing different catalyst are used when gasoline production is required Unreacted feed is recycled to the reactor so that complete conversion of the feed to lower boiling products may be achieved It will be appreciated that the severe operating conditions required in this process necessitate highduty equipment to withstand the high temperatures and pressures large gas compressors and pumps and a hydrogen production unit which makes the capital cost very high
Catalytic Reforming
Catalytic reforming is now one of the most important processes for the production of motor gasolines taking straightrun materials in the boiling range of about 70190℃ as feed and raising the octane number from about 40 to 95100
The main reactions taking place are Dehydrogenation of naphthenes to aromatics
CH2 CH3 CHs
CH2 CH CH2 CH CH3
+3H2
CH2 CH2 CH2 CH
CH2 CH2
a paraffin isomerisation
n hexane 2 methylpentane
b naphthene isomerisation
CH3 CH2
CH2 CH CH2 CH2
CH2 CH2 CH2 CH2
CH2 CH2
The cyclohexane can then dehydrogenate by reaction (1)
Dehydrocyclisation
n heptane methylcyclohexane + H2
The straightchain paraffin can cyclise to the naphthene with production of hydrogen and the naphthene then dehydrogenate to an aromatic by reaction(1)
Hydrocracking
C10H22 + H2 C6H14 + C4H10
Hydrocracking involves the breaking of a carbon chain to give two smaller molecules Paraffins are produced because of the addition of hydrogen to the olefinic fragments resulting from the cracking
All four reactions result in an increase in octane number as in the first three reactions aromatics are produced which have much greater octane numbers than the corresponding paraffins and napthenes and in the fourth reaction low octane number longchain paraffins are destroyed
The catalysts originally developed consisted of platinium (about 03075 per cent weight) on highly purified alumina In the past few years new catalysts have been developed still using platinum as a major component but also adding other metas such as rthenium which improve the life of the catalyst under severe operating conditions
The reactions are carried out at temperatures in the region 490540℃ and pressure 1030 bar There are other side reactions which tend to deactivate the catclyst by the foemation of carbon on it These reactions can be reduced by a high pressure of hydrogen which is maintained by a combination of unit operating pressure and recycle of hydrogen with the feed However yields of reformate are higher at lower pressures whilst a high recycle of hydrogenfeed ratio of 451 (molmol) compared with the previous conditions of about 30 bar and about 81 hydrogenfeed ratio
Dehydrogenation of naphthenes which occurs in the first three reactions is a highly endothermic procss (absorbs heat) and it is necessary to divide the catalyst into a number of separate reactors because the temperature drops so much as the reaction proceeds that its rate becomes too slow and the products have to be reheated to enable the reaction to be completed
Catalytic reforming is a valuable source of hydrogen which is used mainly in desulphurisation units The process is also used for the production of aromatics (egbenzene toluene xvlenes) for use as petrochemical feedstocks
In order to maintain the catalyst at a high level of activity the feedstock must be carefully purified it is preferable to maintain levels of sulphur and water below about two parts per million and eliminate traces of lead It is necessary to burn carbon off the catelyst periodically This is normally done by shutting down the plant However there are versions of the process in which each reactor is taken off stream in turn for regeneration by interchanging with a swing reactor In another case small amounts of catalyst can be removed from and returned to the reactors continuously after regeneration or reactivation steps in which the distribution of metals on the catalyst are adjusted to maintain the catalyst in the most active state
原油加工工艺
脱硫
原油中含硫简单混合物H2S复杂环状结构等种形式原油混合起原油蒸馏程中分解较高沸点硫化物产生H2S进入石油液化气里H2S毒性腐蚀性石油液化气里H2S必须种胺溶液（例二乙醇胺）进行逆流洗涤H2S然单独容器里加热吸收H2S胺溶液脱H2S回收硫胺溶剂生循环作逆流洗涤硫醇作H2S衍生物硫化氢中氢原子碳氢团代硫醇H2S臭味腐蚀性样令愉快性质沸点80℃硫醇极易溶解碱性溶液温度80℃时溶性迅速降低生产石油液化气轻质汽油时采苛性钠溶液进行逆流洗涤硫醇
UOP Merox 硫醇氧化法苛性钠萃取硫醇然硫醇空气氧化生成二硫化物苛性钠生循环氧化步种溶苛性钠金属络合物作催化剂
流程方程表示：
4C2H5SH+4NaOH 4C2H5SNa+2H2O +2H2O
+O2
2C2H5S—SC2H5+4NaOH
二硫化物溶苛性钠形成层油层
沸点80℃250℃间馏分里硫醇萃取Merox溶液里空气氧化生成二硫化物二硫化物腐蚀作没气味然溶油中未达脱硫目产品已臭种氧化硫醇工艺氯化铜作催化剂述两种工艺均加工喷气式发动机燃料
着原油中蒸馏出馏分沸点增高会发现含硫量增生产柴油家庭供暖系统燃料油沸点250℃350℃间沸点范围中东产原油含硫量约1重量种油料燃烧时硫氧化成SO2SO2极易氧化成硫酸会引起气污染金属腐蚀硫碳氢结合结构简单硫醇复杂面介绍方法处理复杂化合物必须裂解硫方法：高温（320℃420℃间）高压（2570巴间）条件原油连氢气起通铝矾土载体氧化钴氧化钼催化剂（制成球压制物）氢气进料例超需例倍时候反应较容易催化剂寿命较长条件硫化物分解硫氢气化合生成H2S硫化物均方法分解影响余碳氢化合物
种脱硫工艺称加氢精制处理种结构硫化物方面效处理原油馏分
原处理种原料设备基相似包括完成列步骤：
1． 合适温度压力反应塔提供进料氢气
2． 冷反应塔出口产品油品冷凝量氢气分离出供反应塔循环
3． H2S少量（2~3）反应程中产生低沸点碳氢化合物
泵输送原料增高求压力通道送进加热炉原料加热炉加热求温度然氢气混合起进入反应塔出反应塔高温产品部分热交换器中新鲜原料冷节省燃料部分热交换器里水冷量氢气卧罐里冷凝油中分离出然台压缩机循环回反应塔里新加进氢气起补充反应中消耗掉部分卧罐中出液体送入蒸馏塔（汽提塔）蒸馏塔里H2S低沸点裂解产品塔底取脱硫产品油
沸点超350℃许原油作生产发电厂船型工厂需重燃料油绝数中东原油含硫量25~4（重量）燃烧种原油会释放出H2S必须建造高烟囱（美国建造干高度500600英尺中高达800影驰烟囱）样H2S会飘散高空避免局部区污染会造成气严重污染理想解决方法脱原油馏分硫遗憾沸点高达550℃左右蒸馏物脱硫相说容易达处理重质原油残渣油尚许困难脱硫工艺困难沸点增高增含硫分子例会增高（达50）说呈现出高例分子必须分解油中微量金属会效脱硫催化剂失活性必须高压（高达170巴）素结果会造成燃料油脱硫成增高者世界范围原油供应形势发展非常强调源保护采方法减少污染时采染料精加工工艺
广泛采脱硫工艺炼厂里达日产100吨H2S容易H2S燃烧生产SO2高烟囱里排放掉样处理理想样造成环境污染需安装装置回收硫H2S氧气供应足情况燃烧生成SO2约三分H2S燃烧结果形成三分二H2S三分SO2混合物H2SSO2化合成硫水：
2H2S+SO23S+2H2O
硫收集起通常出售化学公司生产硫酸
热裂化
碳氢化合物加热450℃开始分解结果分子分裂裂化成较分子石蜡容易裂化次石脑油芳香烃特难裂化时期广泛采热裂化改进石脑油中辛烷值者重馏分生产汽油柴油石脑油热裂化生产汽油质量够高作现代车汽油述工艺已淘汰重油裂化产品求完全加氢满足现代质量求加氢工艺目前极少采果需重馏分（温度高达550℃）变成粗柴油会工艺感兴趣通种热裂化工艺称减粘裂化热裂化粘性原油残渣油复杂分子裂化成较分子降低粘度必粗柴油煤油粘性残渣油混合情况生产出种令满意燃料油
采种热裂化工艺称延迟焦化工艺通常处理低硫原油常压真空蒸馏残渣油生产电极焦（制铝工业）残渣油加热500℃左右进入焦化塔底部塔底部高沸点原料进行裂化反应焦化塔里形成低沸点原料高温气化塔顶部进入分馏系统里分馏成石油气汽油粗柴油塔中留堆孔焦焦化塔结满焦进料送入焦化塔结满焦塔通入蒸汽焦炭时塔进料裂化结焦满正裂化工艺中样液态产品进行加氢处理便作石脑油柴油
催化裂化
热裂化重馏分生产汽油太适宜产生量石油气燃料油伴汽油汽油质量太约三十年前发现：漂白土（硅藻）相似材料起裂化催化剂作生产出高辛烷值汽油（催化裂化）遗憾漂白土容易焦炭覆盖失催化剂作焦炭烧掉催化剂回复先前具活性工艺流程持续进行必须设计出规模持续断交生催化剂方法
达目成功方法采流化技术空气吹细粉末层时粉末状态取决空气速度果速度高（约10米秒粉末似片飞尘吹速度中等时（约1米秒）粉尘空气带动四处转动粉末层起流体作流动流体样保持水状态等等通利特性粉末状催化剂反应生两阶段间持续流通
反应塔生塔分进行设计便升气流速度足输送催化剂原料油（正常沸点350℃550℃间）热（沸点620℃740℃间）生催化剂相遇生催化剂没焦炭汽化油催化剂道输送进入反应塔反应塔里催化剂形成流化层催化剂遇油裂化反应开始反应塔里温度480℃540℃间完成反应催化剂积焦种失效催化剂蒸汽解吸夹带催化剂中碳氢化合物催化剂回生塔里里空气催化剂表面焦炭烧掉石油产品旋风分离器分离催化剂离开反应塔减少催化剂流失然分离成燃料气C3C4汽油粗柴油汽油辛烷值高达95
水蒸汽减活作进料中金属积聚（进料中钒镍含量高达1ppm）催化剂会失活性通断加进新鲜催化剂回收衡催化剂维持总量变保持催化剂活性
直馏粗柴油减压粗柴油焦化粗柴油外假金属含量十分低话输送催化裂化装置进料包括常压残渣油凯洛克重油裂化（HOC）工艺金属含量高常压残渣油设计工艺
目前生产分子筛（沸石）混合具高活性催化剂方面已改进业已发现蒸汽反应塔里长时间阻滞会引起副反应会降低生产汽油选择性产生更气体焦炭新设计省略反应塔流化层输送道里进行反应油催化剂迅速输送道末端分离（例旋风分离器）催化剂输送生塔前先前样进入汽提塔滞留碳氢化合物称短接触时间（SCT）裂化工艺提高生产流程中汽油产量
加氢裂化
碳氢化合物含碳原子数目增加时氢原子数目碳原子例降譬甲烷（CH4）4戊烷（C5H12）24癸烷（C10H22）22果想高沸点碳氢化合物（譬含20碳原子）中生产出低沸点碳氢化合物（譬含510碳原子汽油）必须找增氢碳方法热裂化程中生产出烯烃（氢碳例链烷烃低）催化裂化程中生产出烯烃时碳催化剂沉积作种方法加氢加氢裂化程中通氢气中进行高压裂化完成
工艺灵活性石蜡馏分中高产汽油粗柴油者粗柴油里高产汽油压力150巴170巴温度430℃左右进行操作够承受苛刻条件反应塔需150200毫米厚设计制造程中需考虑许工程难题加氢裂化氢需求量加工立方米石油需高达300立方米左右氢气需求量超催化重整装置氢气必须建造座型制氢工厂供应加氢裂化装置
设计加氢裂化装置生产粗柴油时采座反应塔基流程加氢精制装置十分相似求生产汽油时两装催化剂反应塔没参加反映进料回反应塔里便进料完全变成低沸点产品应注意：工艺求苛刻操作条件需重型设备承受高温高压：型气体压缩机泵制氢装置基投资高
催化重整
目前催化重整生产车汽油重工艺工艺采约70℃~190℃沸点范围直馏原料作进料辛烷值约40提高95~100
发生反应：环烷脱氢生成芳烃
CH2 CH3 CHs
CH2 CH CH2 CH CH3
+3H2
CH2 CH2 CH2 CH
CH2 CH2
a石蜡异构化
n烷 2甲基戊烷
b环烷异构化
CH3 CH2
CH2 CH CH2 CH2
CH2 CH2 CH2 CH2
CH2 CH2
然环烷脱氢反应（1）生成苯
脱氢环化
n烷 甲基环烷+H2
正构烷烃通环化作生成环烷烃伴生出氢气然环烷烃反应（1）脱氢生成种芳香烃
加氢裂化
C10H22 +H2 C6H14+C4H10
加氢裂化包含碳链断裂成两较分子氢加裂化产生烯烃双键生产出烷烃
述四反应结果辛烷值增加头三反应中生成芳香烃辛烷值相应链烷环烷辛烷值相第四反应中辛烷值长链烷烃断裂
原先研制催化剂高纯度矾土铂（约03~o75重量）组成年中已研制出新催化剂然铂作成分加进诸铼样金属苛刻操作条件延长催化剂寿命
反应温度490℃~540℃区间压力10~30巴范围进行外副反应催化剂焦炭催化剂活性降低反应高压氢复原装置操作压力循环氢进料配合维持氢操作压低压情况重整产品产量较高高速循环氢成昂贵新型催化剂该工艺10~15巴压力范围氢进料4~51（克分子克分子）条件运行原条件约30巴氢进料约81
前三反应里进行环烷脱氢种高吸热反应（吸收热量）必须催化剂分散单独反应器中反应开始时温度降太结果反应速度变太慢产品必须重新加热反应完成
催化重整供脱硫装置氢宝贵源种工艺生产芳烃（譬苯甲苯二甲苯）作石油化工生产原料
保持催化剂高度活性进料必须精心加净化硫水保持约百万分二微量铅必须定期催化剂中焦炭烧通常停机进行通轮换生备反应器轮流切断反应器蒸汽进行催化剂生种情况少量催化剂生够断移回反应器里新生程序包括生活化阶段阶段里催化剂金属分布调整催化剂保持佳状态
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Desulphurisation
Sulphur occurs in crude oils combined in a variety of ways from the simplest compound H2S to complex ring structures H2S is produced during distillation of the crude oil by decomposition of higher boiling sulphur compounds and appears in the LPG from which it must be removed because of its poisonous and corrosive nature This is done by counter current washing with an amine (egdiethanolamine) the H2S being removed for sulphur recovery by heating the amine solution in a separate vessel thus regenerating the amine for recycle to the washing stage Mercaptans can be considered derivatives of H2S in which one hydrogen atom is replace by a carbon hydrogen group and share some of its unpleasant properties of bad smell and corrosivity Those mercaptans boiling below about 80℃ are readily dissolved in alkaline solutions but the solubility decreases rapidly above that temperature For LPG and light gasolines therefore the mercaptans can be removed by counter current washing with caustic soda solution
The UOP Merox process uses caustic soda to extract the mercaptans which are then oxidised with air to disulphides and the caustic soda regenerated for further use The oxidation step is assisted by a metal complex catalyst dissolved in the caustic soda
The process can be represented as follow
4C2H5SH+4NaOH 4C2H5SNa+2H2O +2H2O
+O2
2C2H5S—SC2H5+4NaOH
The disulphides are not soluble in caustic soda and form an oil layer which can be removed
Mercaptans in fraction boiling between80℃ and 250℃ cannot be oxidised to disulphides in the Merox solution with air The disulphideswhich are noncorrosive and have little smell remain dissolved in the oil so that no actual desulphurisation has been achived but the products have been sweetened Another process for the oxidation of mercaptans uses copper chloride as a catalyst Both processes can be used in the production of aviation jet fuels
As the cuts taken from crude oil increase in boiling point it is found that the sulphur increases In the 250350℃ range which is used for both diesel fuel and domestic centralheating fuel the sulphur content is about 1 per cent weight from most Middle East crudes When this material is burnt the sulphur is oxidised to SO2 which being easily oxidised to sulphuric acid causes atmospheric pollution and corrosion of metals The sulphur cannot be treated by the methods previously outlined as it is mainly combined with carbon and hydrogen in forms much more complicated than the simple mercaptans These complex compounds have to be broken down to get at the sulphur which is done by passing the oil together with hydrogen at high temperature (320420℃) and high pressure (2570 bar) over a catalyst containing cobalt and molybdenum oxides on an alumina base made in the form of small pellets or extrudates The reaction is easier and the catalyst life better when the ratio of hydrogen to feed is several times higher than that necessary to complete the reaction chemically Under these conditions the sulphur compounds decompose and the sulphur combines with the hydrogen to give H2S Almost all of the sulphur compounds can be decomposed in this way without significantly affecting the remaining hydrocarbons
This process of desulphurisation also called hydrofining is effective in attacking all forms of sulphur compounds and can be used to treat any part of crude oil
In principle the equipment used for all feeds is basically simlar and will contain means for carrying out the following steps
1 Supplythe feed and hydrogen to the reactor at the correct temperature and pressure
2 Cool the reactor product to condense the oil and allow the separation of the excess hydrogen so that it can be recycled to the reactor
3 Remove the H2S and small quantity (23 per cent) of lowboiling hydrocarbons producted in the reaction
A pump takes the feed and raises it to the repuired pressure and passes it through tubes in a furnace where it is heated to the required temperature before being mixed with the hydrogen and passing into the reactor The reactor product is cooled partially by the fresh feed in a heat exchanger to save fuel and partially by water in another heat exchanger Excess hydrogen is separated from the condensed oil in a drum and recirculated back to the reactor by a compressor together with fresh hydrogen to replace the amount consumed in the reaction The liquid from the drum is passed into a distillation column where the H2S and lowboiling breakdown products are removed and the desulphurised oil taken from the bottom of the column
Much of the crude oil boiling above 350℃ is used to make heavy fuel oil for powerstations ships and large industrial plants and can have a sulphur content of 254 per cent weight from most Middle East crudes Buring this material releases SO2 and very high chimneys have to be used (a number in the 500600 foot range have been built one of 800 feet in the USA) so that the SO2 can be dispered widely in the atmosphere thus avoiding localised pollution The ideal solution would be to desulphurise all parts of the crude oil Unfortunately although the desulphurisation of distillates boiling up to about 550℃ cab be relatively easily accomplished the treatment of heavy crudeoil residues poses many difficult problems With increasing boilingpoint the difficulty of desulphurisation increases and also the proportion of molecules containing sulphur becomes high (possibly up to 50 per cent) which means that a high proportion of the molecules present must be decomposed Trace metals in the oil tend to deactivate the most effective desulphurisation catalysts and high pressures (up to 170 bar) must bs used All these factors result in high costs for fueloil desulphurisation Also recent developments in the crudeoil sopply situation worldwide have placed a stong emphasis on energy conservation Consequently fuel intensive processes would be employed only as alast resort when alternative means of miniming pollution are not viable
In a refinery where desulphurisation is used extensively the production of H2S can easily reach 100 tonnes per day Although the H2S could be burnt to SO2 and vented from all stacksit is very undesirable because of the atmospheric pollution caused and additional plant is instslled to recover the sulphur The H2S is burnt to SO2 with the oxygen supply limited so that about onethirt of the H2S burns This gives a mixture of twothirds H2S and onethird SO2 which will combine to form sulphur and water
2H2S+SO23S+2H2O
The sulphur is collected and is usually sold to chemical companies mainly for the manufacture of sulphuricacid
Thermal Cracking
When hydrocarbons are heated to temperatures exceeding about 450℃ they begin to decompose The large molecules breaking or cracking into smaller ones Paraffins are the most easily cracked followed by naphthenes aromatics being extremely refractory At one time thermalcracking processes were widely used to improve the octane number of naphthas or to produce gasoline and gas oil from heavy fractions The quality of the gasoline from the thermal cracking of naphtha is not high enough for present motor gasolines and the process has fallen out of use The products from heavy oil cracking requirements and while at present the process is little used it could be of interest should conversion of heavy distillates (up to 550℃) to gas oils be required One thermalcracking process presently in common use is visbreaking which is the thermalcracking of viscous crudeoil residues to reduce their viscousity by breaking down the large complex molecules to smaller onesA satisfactory fuel oil can them be made without the necessity of using gas oils or kerosine to blend with the viscous residue
Another thermalcracking process presently employed is Delayed Coking which is normally applied toatmospheric or vacuum residues from low sulphur crudes for the production of electrode grade coke (used mostly in aluminium production) The residue is heated to about 500℃ and passed to the bottom of a large drum where the cracking reaction proceeds which breaks down the highboiling materials The lower boiling materials formed vaporise at the high temperature in the drum and pass out of the top to the fractionation system where they are separated into gas gasoline and gas oil and leave behind in the drum a porous mass of coke When the drum is full of coke the feed is switched to another drum which is filled while the full one is steamedout and the coke removed As in the thermalcracking process the liquid products require hydrogenation for use as naphtha or gas oil
Catalytic Cracking
Thermal cracking of heavy distillates for gasoline production is not selective and produces substantial quantities of gas and fuel oil together with the gasoline which is also not of very good quality About thirty years ago it was found that fuller’s earth and simillar materials could act as cracking catalysts and give a good yield of high octane number gasline (catalytic cracking) Unfortunately the fuller’s earth became quickly covered in carbon and no longer acted as a catalyst was returned to its previous activity and thus to operate the process continuously it was necessary to devise methods of alternatively using and regenerating the catalyst continuously on a large scale
One of the most successful methods of achieving this depends on the use of fluidisation When a gas is passed up through a bed of fine power the behaviour of the power depends on the velocity of the gas If it is high (about 1 msec) the particles are moved about by the gas and the bed of power acts like a fluid and can be transported find its own level ect just like a liquid By using this property the catalyst in power form can be circulated continuously between a reaction stage and a regeneration stage
The reactor and regenerator vessels are each designed so that the upward vapour velocity is sufficient to fluidise the catalyst The oil feed (normally boiling 350550℃) meets hot (620740℃) regenerated catalyst which is substantially free of carbon and the vaporised oil and catalyst pass through a transfer line to the reactor where the catalyst forms a fluidised bed The cracking reaction proceeds as soon as catalyst meets the oil and is completed within the reactor at 480540℃ depositing carbon on the catalyst The spent catalyst is steam stripped to remove entrained hydrocarbons and returned to the regenerator where air is used to burn the carbon from the catalyst The oil products leave the reactor via cyclones to reduce catalyst entrainment and are separated into fuel gas C3C4 gasoline and gas oils The gasoline octane number can be as high as 95
The catalyst loses activity as a result of hydrothermal deactivation and the accumulation of metals from the feed which can contain up to 1 ppm of vanadium plus nickel Catalyst activity is maintained by continuous sddition oof fresh catalyst and withdrawal of equilibrium catalyst to maintain a constant inventory
In addition to straightrun and vacuum gas oils coker gas oiletc the feed to a catalytic cracker can include atmospheric residue provided the metals content is low enough The Kellogg heavy oil cracking (HOC) process is designed for high metals content atmospheric residue
Great improvement have been made in the manufacture of catalysts which now incorporate molecular sieve materials (zeolite) and have a very high activity It has been found that the long residence time of the vapours in the reactor gives rise to secondary reactions which reduce the selectivity of the conversion to gasoline and produce more gas and coke New designs dispese with the fluid bed in the reactor and carry out the reaction in the transfer line the oil and catalyst are quickly separated at the end of the transfer line for instance in a cyclone and the catalyst drops into a stripper as previously to the remove entrained hydrocarbons before transfer to the regenerator This is called Short Contact Time (SCT) cracking and has markedly improved the yield of gasoline obtainable in the process
Hydrocracking
As hydrocarbons increase in the number of carbonatoms they contain so there is a decrease in the ratio of the number of hydrogen atoms per carbon atom eg methane CH4 has a ratio of 4 pentane C5H12 has a ratio of 24 decane C10H22 has a ratio of 22 If we wish to produce lowboiling hydrocarbons (eg gasoline containing 510 carbon atoms) from highboiling hydrocarbons containing say 20 carbon atoms we must find some means of increasing the ratio of hydrogen to carbon In thermal cracking olefines (which have a lower hydrogencarbon ratio than paraffins) are produced and also carbon eliminated by deposition in the catalyst The alternative approach is to add hydrogen and this is done in the hydrocracking process by cracking at a very high pressure in hydrogen
This process which is very flexible and can produce high yields of either gasoline or gas oil from wax distillaate or gasoline from gas oil operates at pressures of 150170 bar and temperatures of around 430℃ Reactors capable of withstanding these severe conditions may be 150200 mm thick and pose many difficult engineering problems in design and construction Hydrogen requirements for hydrocracking are very high up to about 300 m3 per m3 of oil processsd which is far in excess of that available from catalytic reformers so that a large hydrogen production plant must be built to supply the hydrocracker
When designed to produce gas oil a hydrocracker will use one reactor and the basicflow diagram appears very similar to a hydrofiner but two reactors containing different catalyst are used when gasoline production is required Unreacted feed is recycled to the reactor so that complete conversion of the feed to lower boiling products may be achieved It will be appreciated that the severe operating conditions required in this process necessitate highduty equipment to withstand the high temperatures and pressures large gas compressors and pumps and a hydrogen production unit which makes the capital cost very high
Catalytic Reforming
Catalytic reforming is now one of the most important processes for the production of motor gasolines taking straightrun materials in the boiling range of about 70190℃ as feed and raising the octane number from about 40 to 95100
The main reactions taking place are Dehydrogenation of naphthenes to aromatics
CH2 CH3 CHs
CH2 CH CH2 CH CH3
+3H2
CH2 CH2 CH2 CH
CH2 CH2
a paraffin isomerisation
n hexane 2 methylpentane
b naphthene isomerisation
CH3 CH2
CH2 CH CH2 CH2
CH2 CH2 CH2 CH2
CH2 CH2
The cyclohexane can then dehydrogenate by reaction (1)
Dehydrocyclisation
n heptane methylcyclohexane + H2
The straightchain paraffin can cyclise to the naphthene with production of hydrogen and the naphthene then dehydrogenate to an aromatic by reaction(1)
Hydrocracking
C10H22 + H2 C6H14 + C4H10
Hydrocracking involves the breaking of a carbon chain to give two smaller molecules Paraffins are produced because of the addition of hydrogen to the olefinic fragments resulting from the cracking
All four reactions result in an increase in octane number as in the first three reactions aromatics are produced which have much greater octane numbers than the corresponding paraffins and napthenes and in the fourth reaction low octane number longchain paraffins are destroyed
The catalysts originally developed consisted of platinium (about 03075 per cent weight) on highly purified alumina In the past few years new catalysts have been developed still using platinum as a major component but also adding other metas such as rthenium which improve the life of the catalyst under severe operating conditions
The reactions are carried out at temperatures in the region 490540℃ and pressure 1030 bar There are other side reactions which tend to deactivate the catclyst by the foemation of carbon on it These reactions can be reduced by a high pressure of hydrogen which is maintained by a combination of unit operating pressure and recycle of hydrogen with the feed However yields of reformate are higher at lower pressures whilst a high recycle of hydrogenfeed ratio of 451 (molmol) compared with the previous conditions of about 30 bar and about 81 hydrogenfeed ratio
Dehydrogenation of naphthenes which occurs in the first three reactions is a highly endothermic procss (absorbs heat) and it is necessary to divide the catalyst into a number of separate reactors because the temperature drops so much as the reaction proceeds that its rate becomes too slow and the products have to be reheated to enable the reaction to be completed
Catalytic reforming is a valuable source of hydrogen which is used mainly in desulphurisation units The process is also used for the production of aromatics (egbenzene toluene xvlenes) for use as petrochemical feedstocks
In order to maintain the catalyst at a high level of activity the feedstock must be carefully purified it is preferable to maintain levels of sulphur and water below about two parts per million and eliminate traces of lead It is necessary to burn carbon off the catelyst periodically This is normally done by shutting down the plant However there are versions of the process in which each reactor is taken off stream in turn for regeneration by interchanging with a swing reactor In another case small amounts of catalyst can be removed from and returned to the reactors continuously after regeneration or reactivation steps in which the distribution of metals on the catalyst are adjusted to maintain the catalyst in the most active state
原油加工工艺
脱硫
原油中含硫简单混合物H2S复杂环状结构等种形式原油混合起原油蒸馏程中分解较高沸点硫化物产生H2S进入石油液化气里H2S毒性腐蚀性石油液化气里H2S必须种胺溶液（例二乙醇胺）进行逆流洗涤H2S然单独容器里加热吸收H2S胺溶液脱H2S回收硫胺溶剂生循环作逆流洗涤硫醇作H2S衍生物硫化氢中氢原子碳氢团代硫醇H2S臭味腐蚀性样令愉快性质沸点80℃硫醇极易溶解碱性溶液温度80℃时溶性迅速降低生产石油液化气轻质汽油时采苛性钠溶液进行逆流洗涤硫醇
UOP Merox 硫醇氧化法苛性钠萃取硫醇然硫醇空气氧化生成二硫化物苛性钠生循环氧化步种溶苛性钠金属络合物作催化剂
流程方程表示：
4C2H5SH+4NaOH 4C2H5SNa+2H2O +2H2O
+O2
2C2H5S—SC2H5+4NaOH
二硫化物溶苛性钠形成层油层
沸点80℃250℃间馏分里硫醇萃取Merox溶液里空气氧化生成二硫化物二硫化物腐蚀作没气味然溶油中未达脱硫目产品已臭种氧化硫醇工艺氯化铜作催化剂述两种工艺均加工喷气式发动机燃料
着原油中蒸馏出馏分沸点增高会发现含硫量增生产柴油家庭供暖系统燃料油沸点250℃350℃间沸点范围中东产原油含硫量约1重量种油料燃烧时硫氧化成SO2SO2极易氧化成硫酸会引起气污染金属腐蚀硫碳氢结合结构简单硫醇复杂面介绍方法处理复杂化合物必须裂解硫方法：高温（320℃420℃间）高压（2570巴间）条件原油连氢气起通铝矾土载体氧化钴氧化钼催化剂（制成球压制物）氢气进料例超需例倍时候反应较容易催化剂寿命较长条件硫化物分解硫氢气化合生成H2S硫化物均方法分解影响余碳氢化合物
种脱硫工艺称加氢精制处理种结构硫化物方面效处理原油馏分
原处理种原料设备基相似包括完成列步骤：
1． 合适温度压力反应塔提供进料氢气
2． 冷反应塔出口产品油品冷凝量氢气分离出供反应塔循环
3． H2S少量（2~3）反应程中产生低沸点碳氢化合物
泵输送原料增高求压力通道送进加热炉原料加热炉加热求温度然氢气混合起进入反应塔出反应塔高温产品部分热交换器中新鲜原料冷节省燃料部分热交换器里水冷量氢气卧罐里冷凝油中分离出然台压缩机循环回反应塔里新加进氢气起补充反应中消耗掉部分卧罐中出液体送入蒸馏塔（汽提塔）蒸馏塔里H2S低沸点裂解产品塔底取脱硫产品油
沸点超350℃许原油作生产发电厂船型工厂需重燃料油绝数中东原油含硫量25~4（重量）燃烧种原油会释放出H2S必须建造高烟囱（美国建造干高度500600英尺中高达800影驰烟囱）样H2S会飘散高空避免局部区污染会造成气严重污染理想解决方法脱原油馏分硫遗憾沸点高达550℃左右蒸馏物脱硫相说容易达处理重质原油残渣油尚许困难脱硫工艺困难沸点增高增含硫分子例会增高（达50）说呈现出高例分子必须分解油中微量金属会效脱硫催化剂失活性必须高压（高达170巴）素结果会造成燃料油脱硫成增高者世界范围原油供应形势发展非常强调源保护采方法减少污染时采染料精加工工艺
广泛采脱硫工艺炼厂里达日产100吨H2S容易H2S燃烧生产SO2高烟囱里排放掉样处理理想样造成环境污染需安装装置回收硫H2S氧气供应足情况燃烧生成SO2约三分H2S燃烧结果形成三分二H2S三分SO2混合物H2SSO2化合成硫水：
2H2S+SO23S+2H2O
硫收集起通常出售化学公司生产硫酸
热裂化
碳氢化合物加热450℃开始分解结果分子分裂裂化成较分子石蜡容易裂化次石脑油芳香烃特难裂化时期广泛采热裂化改进石脑油中辛烷值者重馏分生产汽油柴油石脑油热裂化生产汽油质量够高作现代车汽油述工艺已淘汰重油裂化产品求完全加氢满足现代质量求加氢工艺目前极少采果需重馏分（温度高达550℃）变成粗柴油会工艺感兴趣通种热裂化工艺称减粘裂化热裂化粘性原油残渣油复杂分子裂化成较分子降低粘度必粗柴油煤油粘性残渣油混合情况生产出种令满意燃料油
采种热裂化工艺称延迟焦化工艺通常处理低硫原油常压真空蒸馏残渣油生产电极焦（制铝工业）残渣油加热500℃左右进入焦化塔底部塔底部高沸点原料进行裂化反应焦化塔里形成低沸点原料高温气化塔顶部进入分馏系统里分馏成石油气汽油粗柴油塔中留堆孔焦焦化塔结满焦进料送入焦化塔结满焦塔通入蒸汽焦炭时塔进料裂化结焦满正裂化工艺中样液态产品进行加氢处理便作石脑油柴油
催化裂化
热裂化重馏分生产汽油太适宜产生量石油气燃料油伴汽油汽油质量太约三十年前发现：漂白土（硅藻）相似材料起裂化催化剂作生产出高辛烷值汽油（催化裂化）遗憾漂白土容易焦炭覆盖失催化剂作焦炭烧掉催化剂回复先前具活性工艺流程持续进行必须设计出规模持续断交生催化剂方法
达目成功方法采流化技术空气吹细粉末层时粉末状态取决空气速度果速度高（约10米秒粉末似片飞尘吹速度中等时（约1米秒）粉尘空气带动四处转动粉末层起流体作流动流体样保持水状态等等通利特性粉末状催化剂反应生两阶段间持续流通
反应塔生塔分进行设计便升气流速度足输送催化剂原料油（正常沸点350℃550℃间）热（沸点620℃740℃间）生催化剂相遇生催化剂没焦炭汽化油催化剂道输送进入反应塔反应塔里催化剂形成流化层催化剂遇油裂化反应开始反应塔里温度480℃540℃间完成反应催化剂积焦种失效催化剂蒸汽解吸夹带催化剂中碳氢化合物催化剂回生塔里里空气催化剂表面焦炭烧掉石油产品旋风分离器分离催化剂离开反应塔减少催化剂流失然分离成燃料气C3C4汽油粗柴油汽油辛烷值高达95
水蒸汽减活作进料中金属积聚（进料中钒镍含量高达1ppm）催化剂会失活性通断加进新鲜催化剂回收衡催化剂维持总量变保持催化剂活性
直馏粗柴油减压粗柴油焦化粗柴油外假金属含量十分低话输送催化裂化装置进料包括常压残渣油凯洛克重油裂化（HOC）工艺金属含量高常压残渣油设计工艺
目前生产分子筛（沸石）混合具高活性催化剂方面已改进业已发现蒸汽反应塔里长时间阻滞会引起副反应会降低生产汽油选择性产生更气体焦炭新设计省略反应塔流化层输送道里进行反应油催化剂迅速输送道末端分离（例旋风分离器）催化剂输送生塔前先前样进入汽提塔滞留碳氢化合物称短接触时间（SCT）裂化工艺提高生产流程中汽油产量
加氢裂化
碳氢化合物含碳原子数目增加时氢原子数目碳原子例降譬甲烷（CH4）4戊烷（C5H12）24癸烷（C10H22）22果想高沸点碳氢化合物（譬含20碳原子）中生产出低沸点碳氢化合物（譬含510碳原子汽油）必须找增氢碳方法热裂化程中生产出烯烃（氢碳例链烷烃低）催化裂化程中生产出烯烃时碳催化剂沉积作种方法加氢加氢裂化程中通氢气中进行高压裂化完成
工艺灵活性石蜡馏分中高产汽油粗柴油者粗柴油里高产汽油压力150巴170巴温度430℃左右进行操作够承受苛刻条件反应塔需150200毫米厚设计制造程中需考虑许工程难题加氢裂化氢需求量加工立方米石油需高达300立方米左右氢气需求量超催化重整装置氢气必须建造座型制氢工厂供应加氢裂化装置
设计加氢裂化装置生产粗柴油时采座反应塔基流程加氢精制装置十分相似求生产汽油时两装催化剂反应塔没参加反映进料回反应塔里便进料完全变成低沸点产品应注意：工艺求苛刻操作条件需重型设备承受高温高压：型气体压缩机泵制氢装置基投资高
催化重整
目前催化重整生产车汽油重工艺工艺采约70℃~190℃沸点范围直馏原料作进料辛烷值约40提高95~100
发生反应：环烷脱氢生成芳烃
CH2 CH3 CHs
CH2 CH CH2 CH CH3
+3H2
CH2 CH2 CH2 CH
CH2 CH2
a石蜡异构化
n烷 2甲基戊烷
b环烷异构化
CH3 CH2
CH2 CH CH2 CH2
CH2 CH2 CH2 CH2
CH2 CH2
然环烷脱氢反应（1）生成苯
脱氢环化
n烷 甲基环烷+H2
正构烷烃通环化作生成环烷烃伴生出氢气然环烷烃反应（1）脱氢生成种芳香烃
加氢裂化
C10H22 +H2 C6H14+C4H10
加氢裂化包含碳链断裂成两较分子氢加裂化产生烯烃双键生产出烷烃
述四反应结果辛烷值增加头三反应中生成芳香烃辛烷值相应链烷环烷辛烷值相第四反应中辛烷值长链烷烃断裂
原先研制催化剂高纯度矾土铂（约03~o75重量）组成年中已研制出新催化剂然铂作成分加进诸铼样金属苛刻操作条件延长催化剂寿命
反应温度490℃~540℃区间压力10~30巴范围进行外副反应催化剂焦炭催化剂活性降低反应高压氢复原装置操作压力循环氢进料配合维持氢操作压低压情况重整产品产量较高高速循环氢成昂贵新型催化剂该工艺10~15巴压力范围氢进料4~51（克分子克分子）条件运行原条件约30巴氢进料约81
前三反应里进行环烷脱氢种高吸热反应（吸收热量）必须催化剂分散单独反应器中反应开始时温度降太结果反应速度变太慢产品必须重新加热反应完成
催化重整供脱硫装置氢宝贵源种工艺生产芳烃（譬苯甲苯二甲苯）作石油化工生产原料
保持催化剂高度活性进料必须精心加净化硫水保持约百万分二微量铅必须定期催化剂中焦炭烧通常停机进行通轮换生备反应器轮流切断反应器蒸汽进行催化剂生种情况少量催化剂生够断移回反应器里新生程序包括生活化阶段阶段里催化剂金属分布调整催化剂保持佳状态
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