CN103664478A - Method for increasing yields of low-carbon olefins and aromatics by naphtha steam cracking - Google Patents
Method for increasing yields of low-carbon olefins and aromatics by naphtha steam cracking Download PDFInfo
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Abstract
The invention relates to a method for increasing yields of low-carbon olefins and aromatics by performing steam cracking on a raw material naphtha with the aromatic content of greater than or equal to 9%. According to the method, a backwash-free polar solvent aromatic extraction system is added before a steam cracking device, thereby lowering the aromatic content in the naphtha cracking raw material, enhancing the olefin selectivity in the cracking process, directly increasing the yield of the low-carbon olefins, lowering the coking rate of the equipment and the temperature of the cracking reaction, and prolonging the decoking period. The method pretreats the fed cracking raw material and effectively recycles the aromatic components, so that the total aromatic yield is increased by more than 40% as compared with the pretreatment-free method. By adopting the backwash-free solvent extraction process, the method optimizes the cracking raw material, widens the raw material sources, increases the yields of the low-carbon olefins and aromatics, and effectively lowers the device energy consumption and equipment investment.
Description
Technical field
The present invention relates to a kind of method of increased low carbon olefine output and aromatic hydrocarbons, more particularly, the present invention relates to a kind of solvent extraction petroleum naphtha gained steam cracking of raffinating oil and improve the method for low-carbon alkene and aromatic production.
Technical background
The low-carbon alkene such as ethene, propylene is the basic material of Chemical Manufacture.At present, the main mode of production of low-carbon alkene is steam cracking in the world.Steam cracking device is the tap of petrochemical complex, and its expense of raw materials accounts for 60%～80% of whole device running cost, and the economic benefit of enterprise is had to major effect.Along with ethene production capacity in recent years constantly increases, crude resources is day by day in short supply, ethylene raw imbalance between supply and demand increases gradually, expands its raw material sources and becomes particularly important.Research institution is studied the relation of feedstock property and yield of light olefins both at home and abroad, finds that the normal paraffin content of cracking stock is higher, aromaticity content is lower, by the coking that is more conducive to improve olefins yield He reduce equipment.There are some researches prove mononuclear aromatics and polycyclic aromatic hydrocarbons in raw material, only have side chain cracking to generate the object products such as ethene or propylene.Aromatic ring itself is because the bond energy of C-C conjugated link(age) is up to 611KJ/mol, be difficult to open loop, at 500～900 ℃ of next generation coking precursors, in the katalysis that has furnace tube material nickel alloy steel, in the time of 300～400 ℃, just can dehydrogenation polycondensation generate the poor bituminous matter of mobility, have a strong impact on production.The coking of commerical test proof aromatic hydrocarbons is especially remarkable in the coking of useless pot.Thereby the aromaticity content in reduction raw material, improve normal paraffin content, improve the group composition of raw material, be the fundamental principle that cracking stock is optimized.For this reason, investigators have in succession developed the series of process such as hydrocracking, fractionation by adsorption, Aromatics Extractive Project cracking stock have been processed.
Within 1979, Lummmus company is used hydrogenation tail oil as cracking stock in URBK factory.Hydrocracking process makes diesel raw material generation chain rupture, saturated reaction, in gained hydrogenation tail oil product, is rich in abundant paraffinic hydrocarbons, can effectively improve the productivity of low carbon olefin hydrocarbon of raw material.But adopt hydrocracking technology to optimize cracking stock, to exist hydrogen-consuming volume too high, higher this significant drawback of energy consumption.Also exist to process simultaneously and do the heavy gas oil that surpasses 410 ℃, between hydrogenation tail oil yield and quality, have contradiction, and in tail oil, coronene, ovalene increase and then cause the problems such as cracking apparatus coking with extending running period.
Nineteen seventies U.S. UCC company has developed and has adopted dewaxing by molecular sieve method to improve the IsoSivTM technique of cracking stock.
molecular sieve can adsorb molecule critical diameter at the normal paraffin of 0.49nm, and cannot adsorb isoparaffin, naphthenic hydrocarbon and the aromatic hydrocarbons of molecule critical diameter more than 0.56nm.The normal paraffin utilization decompression, purging, the displacement peak method that are adsorbed in microporous molecular sieve are reclaimed.Utilize this technology can obtain normal paraffin content in raw material and surpass 90% raw material, the yield of ethene of its cracking surpasses 35%, and propene yield is not less than 20%.Calendar year 2001, American UOP company disclosed employing liquid phase simulated moving bed technology, the MaxEne technique based on sorbex technology of normal paraffin in the full fraction naphtha of fractionation by adsorption.Under liquid-phase condition, be adsorbed on normal paraffin on sorbent material after lighter desorbing agent desorption, through the normal paraffin cut of Extract knockout tower, as cracking stock, its yield of ethene reaches 38%.But fractionation by adsorption has isoparaffin and the naphthenic hydrocarbon component of better cracking performance in a large number by loss, thereby raw material consumption is increased considerably, and need to have the throughput of enough naphtha resource guarantee ethene.
As the important means of aromatics separation, Aromatic Extraction Process can obtain useful byproduct when processing cracking stock, thereby how to be applied to process inferior raw material and to become and expand the major issue that ethylene raw source need to discussion.
Patent CN1062293C has developed a kind of nmp solvent extracting heavy gas oil as the method for steam cracking olefin feedstock processed.Heavy gas oil by this method extracting upgrading after the BMCI value of gained extracting upgrading oil be less than 20, raffinate oil cracking ethylene yield and ethene, propylene and divinyl total recovery are greater than respectively 27% and 50%, cracking performance is better than hydrogenation tail oil.This technology is to optimize modification technology for the cracking stock of heavy petroleum hydrocarbon development of raw materials, and cannot be for the upgrading of at present most widely used feed naphtha.
Patent CN1277907C has proposed a kind of petroleum naphtha recombinant processing method, and petroleum naphtha is carried out to extracting and separating, raffinates oil as steam crack material, extracts oil out as reformer feed.But this recombination method does not relate to concrete technology route and the method for extraction process.
Patent 200810223640.3 has proposed a kind of method of utilizing petroleum hydrocarbon to produce low-carbon alkene, method adopts extracting rectification method or solvent extraction process aromatics separation, gained is raffinated oil and is carried out steam cracking, and patent has provided respectively operational path and the processing condition of extracting rectification method or solvent extraction process.Extracting rectification is that the relative volatility that relies on high selective solvent to change aromatic hydrocarbons, non-aromatics realizes the separation of aromatic hydrocarbons, and the extracting of liquid liquid is the different aromatics separations that utilize aromatic hydrocarbons and non-aromatics solubleness in solvent.If select the extracting rectification flow process in this patent, because feed naphtha boiling range is wider, and aromatic hydrocarbons mass fraction is only 7～30%, and a large amount of non-aromatic components in Cutting Tap need to be steamed from tower top, causes process energy consumption higher.And solvent extraction process in patent 200810223640.3 has been selected the band backwash solvent extraction flow process in conventional arene extracting process, three master operations of solvent recuperation that this flow process comprises extracting---put forward and heat up in a steamer backwash---.The process energy consumption of making that adds of extracting backwash operation significantly raises.Add that to put forward the object of heating up in a steamer backwash be the rate of recovery that increases non-aromatics, improve the purity of aromatic hydrocarbon product.The main purpose of this extraction technique is to produce cracking stock, and the thick aromatic hydrocarbons of gained by-product can continue to be fed into hydrogenated pyrolysis gasoline device and continue processing, at this, reclaims non-aromatics wherein and produces aromatic hydrocarbon product.Thereby this method haves much room for improvement.
The object of the invention is to avoid prior art weak point, thereby provide a kind of high aromaticity content petroleum naphtha to increase production the low-carbon alkene of cracker and the low energy consumption technologies method of aromatic production by extracting upgrading simultaneously.
Summary of the invention
The method that the object of this invention is to provide a kind of high aromaticity content feed naphtha producing low-carbon olefins by cracking and aromatic hydrocarbons after without backwash polar solvent extracting pre-separation.
The present invention be take aromaticity content and is more than or equal to the method that 9% petroleum naphtha is raw material steam cracking increased low carbon olefine output and aromatic hydrocarbons, before steam cracking device, increases without backwash polar solvent extracting aromatic hydrocarbons system, said method comprising the steps of:
1) by boiling range, be 30 ~ 210 ℃, aromaticity content is more than or equal to 9% petroleum naphtha introducing without backwash polar solvent extracting pre-separation operation extraction tower, and separation obtains the petroleum hydrocarbon logistics of poor aromatic hydrocarbons and is rich in the thick arene stream of aromatic hydrocarbons;
2) the petroleum hydrocarbon logistics of poor aromatic hydrocarbons step 1) being obtained enters steam cracking device cracking separated;
3) the thick arene stream that is rich in aromatic hydrocarbons step 1) being obtained is sent into hydrocracking gasoline aromatic extraction unit aromatics separation product, and the logistics that is rich in stable hydrocarbon simultaneously obtaining turns back to together with the petroleum hydrocarbon logistics of cracking operation and poor aromatic hydrocarbons and introduces cracking operation;
Wherein, the described poor aromatic hydrocarbons petroleum hydrocarbon through obtaining without backwash polar solvent extracting pre-separation reduces more than 70% compared with the aromaticity content of feed naphtha.
Comprising the following steps without backwash polar solvent extracting pre-separation operation described in step 1):
I) described high aromatic hydrocarbons feed naphtha is introduced to extraction tower bottom, make its in extraction tower with top-down solvent counter current contact, by tower top, obtain raffinating oil of poor aromatic hydrocarbons, by the rich solvent that obtains being rich in aromatic hydrocarbons and solvent at the bottom of tower;
II) the poor aromatic hydrocarbons described step I) obtaining obtains cracking stock after raffinating oil and entering the adverse current washing of water wash column bottom;
III) rich solvent that is rich in aromatic hydrocarbons described step I) obtaining is delivered to solvent recovery tower, is obtained being rich in the logistics of aromatic hydrocarbons by tower top; By the solvent stream that obtains aromatic hydrocarbons mass content at the bottom of tower and be less than 0.5%, after heat exchange, regeneration, return to extracting tower top, complete solvent cycle.
Described polar solvent is selected from one or more in tetramethylene sulfone, 3-methyl sulfolane, N-formyl morpholine, N-Methyl pyrrolidone, methyl phenyl ketone, isophorone and Tetraglycol 99.Preferred tetramethylene sulfone.
Described extraction tower internal solvent and the mass ratio of raw material are 2～8, and the pressure of extraction tower is 0.1～1MPa, and extraction temperature is 40～110 ℃.
In the method for the invention, the tubular reactor high-temperature steam thermal-cracking method of described steam cracking we selected typical ethylene unit, heater outlet temperature is 830 ~ 850 ℃, and the residence time is 0.2 ~ 0.26s, and dilution steam generation ratio is 0.4 ~ 0.6.
Described feed naphtha is less than or equal to C15 for comprising carbonatoms, and the hydrocarbon mixture of aromatic hydrocarbons mass content in 7%～33% scope.
The beneficial effect that the present invention has is as follows:
1) in the method for the invention, because solvent-applied extracting pre-separation operation has reduced the aromaticity content in naphtha cracking raw material.On the one hand, improved the selectivity of cracking process alkene, directly increased the yield of low-carbon alkene, compared with the yield of ethene of the cracking stock without extracting separation, improved approximately 0.8～3.6 percentage point, triolefin yield improves approximately 1.4～6 percentage points; On the other hand, reduce the coking rate of equipment and the temperature of scission reaction simultaneously, extended coke cleaning period.
2) use method of the present invention, in the charging of pre-treatment cracking stock, effectively reclaimed aromatic component, while making total aromatic production without pre-treatment, improve more than 40%.
3) use method of the present invention, because extracting pretreatment process has been selected the solvent extraction flow process without backwash, effectively reduced energy consumption and the solvent load of extractive process.
Accompanying drawing explanation
Fig. 1 is the schematic flow sheet of the method that comprises extracting pre-separation operation of the present invention.
Aromaticity content is more than or equal to 9% feed naphtha to be introduced without the separation of backwash polar solvent extracting pre-separation operation and obtains the petroleum hydrocarbon logistics a of poor aromatic hydrocarbons and be rich in the hydrocarbon mixture logistics b of aromatic hydrocarbons; The petroleum hydrocarbon logistics a of poor aromatic hydrocarbons is introduced to cracking operation and carry out scission reaction, obtain comprising H
2, C
1～C
9the logistics c of hydrocarbon mixture, logistics c is introduced to separation of olefins operation and carries out separation, obtain being rich in C
2alkene, C
3alkene and C
4the logistics d of the hydrocarbon mixture of alkene, Pyrolysis fuel oil PFO e and contain C
6～C
9the hydrocarbon mixture pyrolysis gasoline f of aromatic hydrocarbons; Pyrolysis gasoline f enters hydrogenation process, obtain introducing aromatic hydrocarbons separation circuit together with the logistics b that is rich in aromatic hydrocarbons that hydrocracking gasoline g obtains with pre-separation operation, carry out obtaining BTX aromatics logistics h after separation and aromaticity content is less than or equal to 3% the logistics i that is rich in stable hydrocarbon, after the further rectifying separation of BTX aromatics logistics h, obtain comprising the aromatic hydrocarbon product of benzene, toluene and dimethylbenzene; The logistics i that is rich in stable hydrocarbon turns back to together with the petroleum hydrocarbon logistics a of cracking operation and poor aromatic hydrocarbons as cracking stock.
Fig. 2 is the schematic flow sheet without backwash solvent extraction pre-separation operation of the present invention.
Feed naphtha is introduced to extraction tower bottom, make its in described extraction tower with top-down solvent j logistics counter current contact, by tower top, obtained the k logistics of raffinating oil of poor aromatic hydrocarbons, by the rich solvent l logistics that obtains being rich in aromatic hydrocarbons and solvent at the bottom of tower; The poor aromatic hydrocarbons obtaining is raffinated oil after k logistics enters the adverse current washing of water wash column bottom and is obtained cracking stock a logistics; Solvent recovery tower is delivered in the rich solvent l logistics that is rich in aromatic hydrocarbons, is obtained being rich in the thick arene stream b logistics of aromatic hydrocarbons by tower top; By the solvent j logistics that obtains aromatic hydrocarbons mass content at the bottom of tower and be less than 0.5%, after heat exchange, regeneration, return to extracting tower top, complete solvent cycle.
Embodiment
Embodiment 1
Take Fig. 1 as example illustrates method of the present invention, by be selected from aromaticity content be Tianjin of 9.82% petroleum naphtha introduce shown in Fig. 2 without backwash solvent extraction pre-separation experimental installation, by solvent extraction process, carry out separation.Select tetramethylene sulfone to make solvent, the mass ratio of solvent and charging is 3, and extraction tower pressure is 0.6MPa, and extraction temperature is 50 ℃; Recovery tower pressure is 0.04MPa, and tower top temperature is 29 ℃, and column bottom temperature is 169 ℃, and reflux ratio is 0.8.The aromaticity content obtaining after separation is the petroleum hydrocarbon mixture b that 0.78% petroleum hydrocarbon logistics a and aromaticity content are 50.78%, and before and after extracting pre-separation, the essentially consist character of logistics is as shown in table 1; After the petroleum hydrocarbon logistics a of low arene content mixes with logistics i as In Cracking Feedstock, being heated to after 70 ℃ and being heated to the water vapor of 190 ℃ take after ratio that thinning ratio is 0.5 is mixed and introduces tubular type steam cracking reaction device, in service temperature, it is 835 ℃, the residence time is to carry out scission reaction under the condition of 0.247s, obtains H
2, C
1～C
9hydrocarbon mixture logistics c, this logistics contains C
2～C
4alkene, principal product forms as shown in table 2.After separation, obtain being rich in C
2alkene, C
3alkene and C
4the product d of alkene, Pyrolysis fuel oil PFO e and contain C
6～C
9the hydrocarbon mixture f of aromatic hydrocarbons; Contain C
6～C
9the hydrocarbon mixture f of aromatic hydrocarbons carry out after hydrogenation, the petroleum hydrocarbon mixture b that is rich in aromatic hydrocarbons that gained hydrogenation products hydrocracking gasoline g and pre-separation operation obtain is mixed into aromatic hydrocarbons separation circuit, after separation, obtain the aromatic product such as benzene,toluene,xylene, aromatic hydrocarbons overall yield is in Table 3.Extractive process energy consumption is in Table 4.
Embodiment 2
The Saudi Arabia's feed naphtha that is selected from aromaticity content 10.33% is introduced without backwash solvent extraction pre-separation experimental installation.Select tetramethylene sulfone as solvent, solvent ratio is 3, and extraction tower pressure is 0.5MPa, and extraction temperature is 70 ℃; Recovery tower pressure is 0.035MPa, and tower top temperature is 26 ℃, and column bottom temperature is 165 ℃, and reflux ratio is 1.The aromaticity content obtaining after separation is the thick arene stream b that 1.00% petroleum hydrocarbon logistics a and aromaticity content are 51.38%, and before and after extracting, the essentially consist character of logistics is as shown in table 1; Introducing tube furnace hydrocarbon pyrolysis reactor after poor arene stream a and logistics i Hybrid Heating to 60 ℃ and after being heated to ratio that the water vapor of 180 ℃ is 0.5 in thinning ratio and mixing, in service temperature, it is 835 ℃, the residence time is to carry out scission reaction under the condition of 0.247s, obtains being rich in C
2alkene, C
3alkene and C
4the product of alkene, Pyrolysis fuel oil PFO e and contain C
6～C
9the hydrocarbon mixture f of aromatic hydrocarbons, cracking principal product productive rate is in Table 2; After mixture f hydrogenation, be mixed into aromatic hydrocarbons separation circuit with thick arene stream b, obtain the aromatic product such as benzene,toluene,xylene, aromatic hydrocarbons overall yield is in Table 3.Extractive process energy consumption is in Table 4.
Embodiment 3
The Shandong feed naphtha that is selected from aromaticity content 13.43% is introduced without backwash solvent extraction pre-separation experimental installation.Select tetramethylene sulfone as solvent, solvent ratio is 3, and extraction tower pressure is 1MPa, and extraction temperature is 80 ℃; Recovery tower pressure is 0.038MPa, and tower top temperature is 31 ℃, and column bottom temperature is 173 ℃, and reflux ratio is 1.The aromaticity content obtaining after separation is the thick arene stream b that 3.08% petroleum hydrocarbon logistics a and aromaticity content are 52.47%, and before and after extracting, the essentially consist character of logistics is as shown in table 1; Introducing tube furnace hydrocarbon pyrolysis reactor after poor arene stream a and logistics i Hybrid Heating to 60 ℃ and after being heated to ratio that the water vapor of 180 ℃ is 0.5 in thinning ratio and mixing, in service temperature, it is 840 ℃, the residence time is to carry out scission reaction under the condition of 0.225s, obtains being rich in C
2alkene, C
3alkene and C
4the product of alkene, Pyrolysis fuel oil PFO e and contain C
6～C
9the hydrocarbon mixture f of aromatic hydrocarbons, cracking principal product productive rate is in Table 2; After mixture f hydrogenation, be mixed into aromatic hydrocarbons separation circuit with thick arene stream b, obtain the aromatic product such as benzene,toluene,xylene, aromatic hydrocarbons overall yield is in Table 3.Extractive process energy consumption is in Table 4.
Embodiment 4
The C of aromaticity content 24.91% will be selected from
4～C
15the feed naphtha of hydrocarbon is introduced without backwash solvent extraction pre-separation operation.Select tetramethylene sulfone as solvent, solvent ratio is 3, and extraction tower pressure is 0.9MPa, and extraction temperature is 80 ℃; Recovery tower pressure is 0.04MPa, and tower top temperature is 40 ℃, and column bottom temperature is 173 ℃, and reflux ratio is 0.9.The aromaticity content obtaining after separation is the thick arene stream b that 5% petroleum hydrocarbon logistics a and aromaticity content are 64.94%, and before and after extracting, the essentially consist character of logistics is as shown in table 1; Introducing tube furnace hydrocarbon pyrolysis reactor after poor arene stream a and logistics i Hybrid Heating to 60 ℃ and after being heated to ratio that the water vapor of 180 ℃ is 0.5 in thinning ratio and mixing, in service temperature, it is 835 ℃, the residence time is to carry out scission reaction under the condition of 0.225s, obtains being rich in C
2alkene, C
3alkene and C
4the product of alkene, Pyrolysis fuel oil PFO e and contain C
6～C
9the hydrocarbon mixture f of aromatic hydrocarbons, cracking principal product productive rate is in Table 6; After mixture f carries out hydrogenation, gained mixture is mixed into aromatic hydrocarbons separation circuit with thick arene stream b, obtains the aromatic product such as benzene,toluene,xylene, and aromatic hydrocarbons overall yield is in Table 3.The unit raw material total energy consumption of extractive process is in Table 4.
Table 1: cracking stock carries out extracting pre-treatment front and back logistics property
Table 2: the cracking yield of main split product
Table 3: aromatic hydrocarbons total recovery
Table 4: solvent extraction pre-treatment energy consumption
Comparative example 1
In the situation that guaranteeing that cracker inlet amount is constant, by embodiment 1, be that the present invention adds the cracking flow process of extracting pre-separation to be contrasted without pretreatment process with conventional.Table 7 be in two kinds of situations under identical pyrolyzer operational condition the yield result of primary product.Table 8 is aromatics yield and the aromatic production result of variations of whole flow process under two kinds of flow processs.
Comparative example 2
Embodiment 2 is compared with cracking yield and the aromatic production of the conventional cracking stock without pretreatment process.Cracking principal product yield and process total arenes yield the results are shown in Table 7 with table 8.
Comparative example 3
Embodiment 3 is compared with cracking yield and the aromatic production of the conventional cracking stock without pretreatment process.Cracking principal product yield and process total arenes yield the results are shown in Table 7 with table 8.
Comparative example 4
Embodiment 4 is compared with cracking yield and the aromatic production of the conventional cracking stock without pretreatment process.Cracking principal product yield and process total arenes yield the results are shown in Table 7 with table 8.
Table 5: without extracting with through the composition contrast of the cracking primary product of extracting raw material
Table 6: without the aromatic production contrast of extracting and process extracting flow process
In the raw material after the visible extracting of table 1, Determination of Alkane Content obviously increases, and aromaticity content reduces 77 ~ 92wt%.The yield of ethene of analytical table 5 available cracking process improves 1.6 ~ 3.5wt%, and propene yield improves 0.6 ~ 1.3wt%, and divinyl yield improves 0.4 ~ 0.9wt%, and triolefin total recovery improves 2.6 ~ 5.7wt%; The total arenes yield of whole production process has improved 5.59 ~ 13.23wt% simultaneously, and the output of aromatic hydrocarbons has improved more than 60%.
Comparative example 5
During same feed naphtha, extracting pre-separation operation is selected without backwash solvent extraction process (embodiment 2) and contrasted with selecting employing extracting rectification technique (embodiment 5).
Embodiment 5: the flow process of extracting rectification technique is: feed naphtha enters the above cut of Cutting Tap excision carbon 9, pressure tower 0.05MPa, 130 ℃ of tower tops, at the bottom of tower 196 ℃, reflux ratio 1.2.Gained overhead stream is sent into extracting rectification tower middle part, solvent enters from tower top, solvent conducts heat with petroleum hydrocarbon steam counter current contact in decline process, mass transfer, select sulfolane solvent, the mass ratio of solvent and raw material is 3, and tower top pressure is 0.05MPa, and tower top temperature is 102 ℃, column bottom temperature is 171 ℃, and reflux ratio is 0.68.Tower top obtains poor arene stream to be mixed with Cutting Tap tower base stream as cracking stock.Recovery tower is sent in the logistics that obtains being rich in aromatic hydrocarbons and solvent at the bottom of tower, and the tower top pressure of recovery tower is 0.04Mpa, and tower top temperature is 30 ℃, and column bottom temperature is 162 ℃, and reflux ratio is 2.5.Tower top obtains being rich in the logistics of aromatic hydrocarbons, send hydrogenated pyrolysis gasoline aromatic extraction unit; At the bottom of tower, obtaining aromatic hydrocarbons mass content is less than 0.5% solvent stream and returns to extracting rectification tower and recycle.
Table 7: without the energy consumption comparison of backwash solvent extraction process and extracting rectification technique
Note: in ethylene yield per ton, in table, difference is that extracting rectification flow process deducts the difference without backwash solvent extraction flow process
From table 7, energy consumption without backwash solvent extraction process is starkly lower than extracting rectification process energy consumption, and this is mainly because feed naphtha boiling range is wider, and aromatic hydrocarbons mass fraction is only 7～30%, a large amount of non-aromatic components in Cutting Tap need to be steamed from tower top, cause process energy consumption high.Although the inlet amount of follow-up hydrogenated pyrolysis gasoline Aromatics Extractive Project operation increases to some extent when selecting without backwash solvent extraction process, increasing amount and feed naphtha amount gap are larger, make this energy consumption increased value less on the total energy consumption impact of two extractive processs, thereby feed naphtha extracting pre-treatment selects without backwash solvent extraction process compared with extracting rectification technique, process energy consumption significantly reduces.
Comparative example 6
During same feed naphtha, extracting pre-separation operation is selected without backwash solvent extraction process (embodiment 2) and added the solvent extraction process (embodiment 6) of backwash to contrast with selecting employing.
Embodiment 6: add the flow process of the solvent extraction process of backwash to be: feed naphtha is introduced extraction tower middle part and top-down solvent counter current contact, selects sulfolane solvent, and solvent ratio is 3.8, and the pressure of extraction tower is 0.7MPa, and extraction temperature is 90 ℃.By tower top, obtain poor arene stream, poor arene stream is as cracking after washing, and its aromaticity content and embodiment 2 are all 1.0wt%; By the logistics that obtains being rich in aromatic hydrocarbons and solvent at the bottom of tower; After tower base stream and the heat exchange of extraction tower solvent stream, enter to carry and heat up in a steamer tower, overhead product returns to backwash at the bottom of extraction tower tower as backflow aromatic hydrocarbons, and the mass ratio of backwash liquor and raw material is 0.02.The rich solvent that is rich in aromatic hydrocarbons obtaining at the bottom of tower is delivered to recovery tower, and recovery tower pressure on top surface is 0.035MPa, and column bottom temperature is 169 ℃, and reflux ratio is 0.8, is obtained being rich in the logistics of aromatic hydrocarbons by tower top, sends into hydrogenated pyrolysis gasoline aromatic hydrocarbons separation circuit; Solvent stream by obtaining aromatic hydrocarbons mass content at the bottom of tower and being less than 0.5%, returns to extracting tower top after heat exchange, complete solvent cycle.
Table 8: without backwash solvent extraction and the energy consumption comparison that adds backwash solvent extraction process
Note: in ethylene yield per ton, in table, difference is to add backwash solvent extraction flow process to deduct the difference without backwash solvent extraction flow process
From table 8, without the energy consumption of backwash solvent extraction process, lower than adding backwash extraction process energy consumption, this is to make adding of tower process energy consumption increase owing to carrying on the one hand heating up in a steamer, and adding of backwash liquor solvent load is increased on the other hand, causes extractive process energy consumption to increase.Equally, although the inlet amount of follow-up hydrogenated pyrolysis gasoline Aromatics Extractive Project operation increases to some extent when selecting without backwash solvent extraction process, but increasing amount and feed naphtha amount gap are larger, make this energy consumption increased value less on the total energy consumption impact of two extractive processs, thereby feed naphtha extracting pre-treatment selects without backwash solvent extraction process and add backwash extraction process, process energy consumption significantly reduces.
Claims (7)
1. the aromaticity content of take is more than or equal to the method that 9% petroleum naphtha is raw material steam cracking increased low carbon olefine output and aromatic hydrocarbons, it is characterized in that, before steam cracking device, increases without backwash polar solvent extracting aromatic hydrocarbons system, said method comprising the steps of:
1) by boiling range, be 30 ~ 210 ℃, aromaticity content is more than or equal to 9% petroleum naphtha introducing without backwash polar solvent extracting pre-separation operation extraction tower, and separation obtains the petroleum hydrocarbon logistics of poor aromatic hydrocarbons and is rich in the thick arene stream of aromatic hydrocarbons;
2) the petroleum hydrocarbon logistics of poor aromatic hydrocarbons step 1) being obtained enters steam cracking device cracking separated;
3) the thick arene stream that is rich in aromatic hydrocarbons step 1) being obtained is sent into hydrocracking gasoline aromatic extraction unit aromatics separation product, and the logistics that is rich in stable hydrocarbon simultaneously obtaining turns back to together with the petroleum hydrocarbon logistics of cracking operation and poor aromatic hydrocarbons and introduces cracking operation;
Wherein, the described poor aromatic hydrocarbons petroleum hydrocarbon through obtaining without backwash polar solvent extracting pre-separation reduces more than 70% compared with the aromaticity content of feed naphtha.
2. method according to claim 1, is characterized in that, comprising the following steps without backwash polar solvent extracting pre-separation operation described in step 1):
I) described high aromatic hydrocarbons feed naphtha is introduced to extraction tower bottom, make its in extraction tower with top-down solvent counter current contact, by tower top, obtain raffinating oil of poor aromatic hydrocarbons, by the rich solvent that obtains being rich in aromatic hydrocarbons and solvent at the bottom of tower;
II) the poor aromatic hydrocarbons described step I) obtaining obtains cracking stock after raffinating oil and entering the adverse current washing of water wash column bottom;
III) rich solvent that is rich in aromatic hydrocarbons described step I) obtaining is delivered to solvent recovery tower, is obtained being rich in the logistics of aromatic hydrocarbons by tower top; By the solvent stream that obtains aromatic hydrocarbons mass content at the bottom of tower and be less than 0.5%, after heat exchange, regeneration, return to extracting tower top, complete solvent cycle.
3. method according to claim 2, is characterized in that, described polar solvent is selected from one or more in tetramethylene sulfone, 3-methyl sulfolane, N-formyl morpholine, N-Methyl pyrrolidone, methyl phenyl ketone, isophorone and Tetraglycol 99.
4. method according to claim 3, is characterized in that, described polar solvent is tetramethylene sulfone.
5. method according to claim 2, is characterized in that, in described extraction tower, the mass ratio of polar solvent and raw material is 2～8, and extraction tower pressure is 0.1～1MPa, and extraction temperature is 40～110 ℃.
6. method according to claim 1, it is characterized in that, the tubular reactor high-temperature steam thermal-cracking method of described steam cracking method we selected typical ethylene unit, heater outlet temperature is 830 ~ 850 ℃, the residence time is 0.2 ~ 0.26s, and dilution steam generation ratio is 0.4 ~ 0.6.
7. method according to claim 1, is characterized in that, described feed naphtha is less than or equal to C15 for comprising carbonatoms, the hydrocarbon mixture of aromatic hydrocarbons mass content in 7%～35% scope.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105482858A (en) * | 2015-11-20 | 2016-04-13 | 清华大学 | Substitute used for evaluation of physical and chemical properties of naphtha |
| CN109694301A (en) * | 2017-10-20 | 2019-04-30 | 中国石油化工股份有限公司 | A method of using Aromatic raffinate as raw materials for ethylene production |
| CN112933658A (en) * | 2021-01-25 | 2021-06-11 | 北方华锦化学工业股份有限公司 | Method and device for reducing solvent in raffinate oil of aromatic extraction device |
| CN114478160A (en) * | 2020-10-26 | 2022-05-13 | 中国石油化工股份有限公司 | Method and system for preparing low-carbon olefin from crude oil |
| CN115725327A (en) * | 2021-08-30 | 2023-03-03 | 中国石油化工股份有限公司 | System and method for producing ethylene by steam thermal cracking |
| CN115725336A (en) * | 2021-08-30 | 2023-03-03 | 中国石油化工股份有限公司 | System and method for improving yield of triene triphenyl in ethylene device |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105482858A (en) * | 2015-11-20 | 2016-04-13 | 清华大学 | Substitute used for evaluation of physical and chemical properties of naphtha |
| CN109694301A (en) * | 2017-10-20 | 2019-04-30 | 中国石油化工股份有限公司 | A method of using Aromatic raffinate as raw materials for ethylene production |
| CN114478160A (en) * | 2020-10-26 | 2022-05-13 | 中国石油化工股份有限公司 | Method and system for preparing low-carbon olefin from crude oil |
| CN114478160B (en) * | 2020-10-26 | 2024-05-07 | 中国石油化工股份有限公司 | Method and system for preparing low-carbon olefin from crude oil |
| CN112933658A (en) * | 2021-01-25 | 2021-06-11 | 北方华锦化学工业股份有限公司 | Method and device for reducing solvent in raffinate oil of aromatic extraction device |
| CN115725327A (en) * | 2021-08-30 | 2023-03-03 | 中国石油化工股份有限公司 | System and method for producing ethylene by steam thermal cracking |
| CN115725336A (en) * | 2021-08-30 | 2023-03-03 | 中国石油化工股份有限公司 | System and method for improving yield of triene triphenyl in ethylene device |
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