Summary of the invention
Usually, the present invention relates to a kind of novel method, this method comprises that two hydrodesulfurisationstep step and a centre remove H
2The step of S, this method can be simultaneously:
-according to these countries, reach the technological standard of motor benzine in the future, i.e. the about 30ppm of sulphur content, even 10ppm,
Olefin hydrogenation process in the described method of-control,
The loss of octane number that-restriction is relevant with hydrodesulfurizationprocess process,
-reduce mercaptans content so that in sweet gasoline certain sulphur and olefin(e) centent.
More properly, the present invention relates to a kind of hydrocarbon cut sulfur method that contains sulphur compound and olefin(e) compound, this method comprises following at least sequential step:
-causing described cut desulfurization degree strictly to be higher than under 90% the condition, desulfurization for the first time in the presence of hydrogen and Hydrobon catalyst,
-from hydrogen sulfide (H from separation major portion the effluent of the desulfurization first time
2S),
-in the presence of hydrogen and Hydrobon catalyst, be lower than at the desulfurization degree that causes described effluent under the condition of desulfurization degree of desulfurization for the first time, from the separating step and the desulfurization second time of removing the effluent of hydrogen sulfide.
Therefore, this sulfur method proposes a kind of high desulfurization rate that reaches, and typically is higher than 95%, more properly is higher than 99%, simultaneously the terms of settlement that limits the loss of octane that is produced by hydrogenated olefins and form recombination mercaptan.Produce low-sulfur and low thioalcohol and high-octane gasoline thus.
The present invention relates to a kind of sulfur method that contains the hydrocarbon cut of sulphur compound and olefin(e) compound, this method comprises following at least sequential step:
-causing described cut desulfurization degree strictly to be higher than under 90% the condition, desulfurization for the first time in the presence of hydrogen and Hydrobon catalyst,
-from hydrogen sulfide (H from separation major portion the effluent of the desulfurization first time
2S),
-in the presence of hydrogen and Hydrobon catalyst, be lower than under the condition of desulfurization degree of desulfurization for the first time the desulfurization second time of removing the effluent of hydrogen sulfide from separating step at the desulfurization degree that causes described effluent.
In the method for the invention, preferably at least a Hydrobon catalyst contains at least a period of element sorted table group VIII element, and more preferably at least a catalyzer also contains at least a period of element sorted table group vib element.
Most preferably, described Hydrobon catalyst contains at least a period of element sorted table group VIII element and at least a period of element sorted table group vib element that is selected from molybdenum and tungsten that is selected from nickel and cobalt.
Preferably, the desulfurization first time of the inventive method is to carry out under the following condition: temperature 250-350 ℃, pressure 1-3 MPa, liquid hourly space speed 1-10 hour
-1, and H
2/ HC than 50-500 liter/liter, preferably, desulfurization for the second time is to carry out under the following condition: temperature 200-300 ℃, pressure 1-3 MPa, liquid hourly space speed 1-10 hour
-1, and H
2/ HC than 50-500 liter/liter.
Preferably, the desulfurization degree of desulfurization for the second time is that strictness is higher than 80%, and more preferably, the difference of the desulfurization degree of desulfurization for the first time and the desulfurization degree of desulfurization for the second time is one of absolute value percentage at least.Such difference can reach by following method especially: by for the first time and the temperature head between the desulfurization second time and/or per hour volumetric velocity is poor, and/or by first with second hydrodesulfurisationstep step in the different catalytically active of use catalyzer, for example according to the composition of these catalyzer or preparation method's difference.
Method of the present invention randomly can also be included in the selective hydration replenish step that contains diolefine in the hydrocarbon cut, and described step was carried out before the desulfurization first time.More preferably, this method can also comprise the replenish step that light sulfocompound increases the weight of, and described step was carried out before the desulfurization first time, can also comprise that most preferably described cut is separated at least one replenish step of at least two kinds of cuts, wherein:
-contain the very lighting end of small portion sulfocompound,
-contain the last running of major portion sulfocompound, then, described at least last running can be handled according to first desulfurized step.
Method of the present invention preferably is applicable to the material of the gasoline fraction of Tathagata autocatalysis cracking or coking of hydrocarbonaceous heavy burder or steam cracking.
Will be better understood the present invention by the embodiment of the present invention of reading following pure illustrative and provide without limitation.
Embodiment
According to following preferred but non-imposed embodiment of the present invention, material to be desulfurization is in advance in selective hydration diolefine (step a) and add (the non-imposed processing in the reactor chain of step b) of heavy and light sulfocompound.Pretreated like this material redistillation is fractionated at least two kinds of cuts (step c): the heavy petrol of the petroleum naphtha of poor sulphur rich olefins and the poor alkene of rich sulphur.Generally contain sulphur below the 50ppm from the lighting end of three preceding step, the following sulphur of 20ppm preferably, the following sulphur of 10ppm most preferably, this cut did not generally need to carry out last processing before adding as the gasoline base-material.Last running from three preceding step has concentrated most of sulphur, can handle according to purpose method of the present invention.The advantage of this preferred implementation is to make loss of octane minimum, because hydrogenant has the light olefin of 5 carbon atoms not deliver to hydrodesulfurizationsection section easily.
Usually, these pre-treatment step a), b) and experiment condition c) as follows:
1) selective hydration effect (step a):
This gasoline pre-treatment optional step to be desulfurization is to be used for removing the diolefine that gasoline exists to small part.This diene hydrogenation effect is a non-imposed but favourable step, and in fact this step can remove the whole diene that exist in the pending cut before hydrotreatment.These diolefine are polymeric natural gum precursors in hydrotreating reactor, and limit their life-span.
Carry out in the presence of a kind of catalyzer as this step 1, this catalyzer contains at least a group VIII metal, preferably is selected from VII family metal and a kind of carrier of platinum, palladium and nickel.For example use a kind of 1-20 of containing weight % to be deposited on inert support, like aluminum oxide, silicon-dioxide, silica-alumina, nickel aluminate, or contain the catalyzer of the nickel at least 50% alumina supporter.This catalyzer is usually pressure 0.4-5 MPa, temperature 50-250 ℃ and liquid hourly space speed 1-10 hour
-1Operate under the condition.Another group vib metal that can associate for example as molybdenum and tungsten, generates bimetallic catalyst.Associate as this group vib metal and group VIII metal, the group vib metal deposits on carrier up to 1-20 weight %.
The selection operation condition is a particularly important.More generally, comparing in the presence of the excessive a little amounts of hydrogen, under pressure, operate with the needed stoichiometric calculation value of hydrogenated diene hydrocarbon.Hydrogen and treating material are with the preferably catalyst fixed bed reactor of flow pattern injection up or down.This temperature more generally is 50-300 ℃, preferably 80-250 ℃, and more preferably 120-210 ℃.
This pressure should be selected to such an extent that be enough to make more than the 80 weight %, and preferably the above pending gasoline of 95 weight % remains in the reactor with liquid phase: its pressure more generally is the 0.4-5 MPa, preferably is higher than 1 MPa.Favourable pressure is between the 1-4 MPa, comprises its cut off value.
Under these conditions, space velocity is about 1-12 hour
-1, preferably 4-10 hour
-1
Lighting end can contain the diolefine up to percentum weight in the gasoline fraction of catalytic pyrolysis.After hydrogenization, diene content is reduced to below the 3000ppm, even below the 2500ppm, better below the 1500ppm.In some cases, can reach the diene content that is lower than 500ppm.Diene content behind the selective hydration in some cases even be reduced to below the 250ppm.
The diolefine selective hydrogenation is supervened the isomerization of outer olefinic double bonds, causes generating internal olefin.The result of this isomerization has generated by the saturated more resistant to elevated temperatures alkene of hydrogen, causes octane value to increase (or because of the low octane value that compensated of alkene loss) a little.This perhaps generally is higher than the reason of terminal olefine owing to the octane index of internal olefin.
According to one embodiment of the present invention, in the hydrogenation catalyticreactor, carry out the diene hydrogenation step, this reactor comprises at least one usually whole material and carries out the catalyzed reaction section that the necessary hydrogen amount of expected response is passed through.
2) light sulfocompound increases the weight of (step b)
This optional step is that promptly its boiling point is lower than the compound of thiophene boiling point with saturated light sulfide, changes into saturated sulfocompound, and its boiling point is higher than the compound of thiophene boiling point.These light sulfocompounds are mercaptan, the CS of 1-5 carbon atom typically
2With the sulfide that contains 2-4 carbon atom.This transformation preferably has the catalyzer of at least a group VIII (element classification periodictable the 8th, 9 and 10 families) element to carry out on aluminum oxide, silicon-dioxide or silica-alumina or nickel aluminate class carrier with a kind of.Selecting catalyst especially so that promote reaction between light mercaptans and the alkene, obtains mercaptan or sulfide that boiling point is higher than thiophene.
This optional step can randomly use same catalyzer and step a) to carry out simultaneously.For example, during the hydrogenated diene hydrocarbon, operation is particularly advantageous under the condition that the compound that is the mercaptan form as at least a portion is transformed.
In this case, these temperature generally are 100-300 ℃, preferably 150-250 ℃.H
2/ material ratio is adjusted to and whenever is upgraded to the 1-20 liter, preferably every liter of 3-15 liter.Space velocity generally is 1-10 hour
-1, preferably 2-6 hour
-1, pressure is the 0.5-5 MPa, preferably the 1-3 MPa.
3) gasoline be separated at least two kinds of cuts (step c):
This step is chosen wantonly.At step a) and b) after when carrying out this step, this step can produce the petroleum naphtha of desulfurization, this gasoline often contains the following mercaptan of 50ppm.In this step process, gasoline is fractionated at least two kinds of cuts:
-lighting end, the residual sulphur content of its cut is very limited, is preferably lower than about 50ppm, more preferably is lower than about 20ppm, most preferably is lower than about 10ppm, and need not be intended to reduce sulphur content other one or more handle and just can use this cut,
-last running has wherein concentrated most of sulphur, i.e. nascent whole sulphur in material, and the sulphur of not finding in petroleum naphtha.
Preferably use common distillation tower to carry out this separation.This separation column should be able to the gasoline lighting end that contains small portion sulphur with contain preferably that the last running of nascent most of sulphur separates in feed gasoline.
The petroleum naphtha that obtains by this separation generally contains whole at least five carbon atom alkene, preferably five carbon atom compounds and at least 20% six carbon atom alkene.Usually, at step a) and b) after this lighting end sulphur content that obtains very low, promptly do not need to handle this lighting end as last acting as a fuel to use.
The gasoline that a kind of alternative of the inventive method that use describes below is handled is directly to come the unitary pyrolysis gasoline of autothermic cracking, or the step a), the b that describe in front) or c) in the pretreated pyrolysis gasoline of at least one step.
Method of the present invention is included in two step d) and the f in two differential responses sections), and between two hydrodesulfurizationsection section, separate H
2The step e) of S.
(step d) is in the presence of hydrogen to first step of hydrogenating desulfurization, and at temperature 250-350 ℃, preferably 270-320 ℃ and pressure 1-3 MPa preferably under the 1.5-2.5 MPa, allow pending gasoline pass through Hydrobon catalyst.Liquid space velocity generally is 1-10 hour
-1, preferably 2-5 hour
-1, H
2/ HC is than being 50-500 liter/liter (l/l), preferably 100-400 liter/liter (l/l), more preferably 150-300 liter/liter (l/l).H
2/ HC ratio is at 1 normal atmosphere and the ratio of 0 ℃ of following hydrogen flowing quantity with flow of hydrocarbon.Under these conditions, this is reflected in the gas phase and carries out.The desulfurization degree that reaches in this step process strictly is higher than 90%, and the gasoline that promptly for example begins the 2000ppm sulphur that contains can change into the gasoline that contains the following sulphur of 200ppm.Operational condition should be regulated according to the characteristic for the treatment of material in this step process, reaches desulfurization degree and strictly is higher than 90%, preferably is higher than 92%, most preferably is higher than 94%.Effluent from this first hydrodesulfurisationstep step is the gasoline of partial desulfurization, and residual hydrogen and sulfocompound decompose the H that produces
2S.
After this step is most of H
2Separating step (the step e) of S and other effluent.This step is used for removing at least 80%, preferably at least 90% H that produces in the step d) process
2S.Can adopt the various different modes in most of mode known to those skilled in the art to remove H
2S.For example can enumerate a lot of metal oxide absorption H
2S, these metal oxides preferably are selected from zinc oxide, cupric oxide or molybdenum oxide.This adsorbent is preferably reproducible, and for example can regenerate with continuous or discontinuous manner by thermal treatment under oxidation or reductive atmosphere.Can in fixed bed or moving-bed, use this adsorbent.Another relatively classic methods be cooling step d) effluent, obtain a kind of liquid and a kind of H of being rich in
2And H
2The gas of S.Use the amine washing plant of those skilled in the art's well-known functions, can be with H
2S and H
2Separate.
Second step f) of desulfurization is the deep desulfurization of gasoline that is used for carrying out from step e), up to the sulphur content of looking for.This step is at temperature 200-300 ℃, and preferably 240-290 ℃, pressure 1-3 MPa preferably under the 1.5-2.5 MPa, allows gasoline from step e) mix with hydrogen and passes through Hydrobon catalyst.Liquid space velocity generally is 1-10 hour
-1, preferably 2-8 hour
-1, H
2/ HC is than being 50-500 liter/liter (l/l), preferably 100-400 liter/liter (l/l), more preferably 150-300 liter/liter (l/l).Under these conditions, in gas phase, carry out this reaction.Gasoline of handling in this step process and hydrogen mixture contain the H below the 100ppm
2S, the preferably following H of 50ppm
2S.The operational condition of this step should be that desulfurization degree can reach needed sulphur content, keeps desulfurization degree to be lower than the operational condition of first step desulfurization degree simultaneously.The treating material sulphur content is more much lower than the beginning material in this step process, and the desulfurization degree of looking for is also lower.Therefore, catalyst volume of Xu Yaoing and service temperature generally also are lower.For example, desulfurized step f) VVH (per hour volumetric velocity) can be higher 1.5 times than the VVH of step d), and/or desulfurized step f) temperature for example can be than low at least 10 ℃ of the temperature of step d), advantageously at least 20 ℃.Often, the volume of industrial equipments stagnant catalyst, at this moment, the desulfurization degree of step f) mainly is to regulate by temperature.But, by to step d) or f) in any known parameters of working of each step desulfurization degree, for example implementation step f) time use the catalyzer lower than step d) catalyst activity, can regulate described difference, do not exceed scope of the present invention.For example, step f) is used and to be contained than the low amount of metal of step d) catalyzer or than the catalyzer of small specific surface carrier, can obtain step d) and f) catalyzer between poor activity.Another terms of settlement is to use the catalyzer of part inactivation in step f).
Therefore, be adjusted in operational condition in the step f) process, often reach and strictly be higher than 80%, preferably be higher than 85%, most preferably be higher than 92%, even be higher than 95% desulfurization degree according to the treating material characteristic.
The difference of the desulfurization degree of first and second hydrodesulfurisationstep step generally is to be higher than 1% with absolute value representation, preferably is higher than 2%, most preferably is higher than 3%.
Astoundingly, the applicant in fact finds, step d) and f) separately this constraint condition of desulfurization degree that the sulfur in gasoline alcohol content of production is reduced to is minimum, make thus later any gasoline desulfur (alcohol) (adoucissement) step become non-imposed or less compulsory.
According to a kind of enforcement alternatives of the inventive method, also possible is to inject new hydrogen in second hydrodesulphurisatioreactors reactors, so that separate gasoline and the hydrogen that produces, and will generally contain the following H of 200ppm
2This hydrogen of S injects first hydrodesulfurisationstep step.
At step d) and f) catalyzer that uses in the process contains at least a group VIII element and/or at least a group vib element on suitable carrier.
The group VIII metal content of representing with oxide compound generally is 0.5-15 weight %, preferably 1-10 weight %.The group vib metal content generally is 1.5-60 weight %, preferably 3-50 weight %.
When having the group VIII element, it is cobalt preferably, and when having the group vib element, it usually is molybdenum or tungsten.This support of the catalyst is the porous solid normally, for example as aluminum oxide, silica-alumina or other porosu solid, for example as the magnesium oxide, silicon-dioxide or the titanium dioxide that use or mix with aluminum oxide or silica-alumina use separately.Minimum for the olefin hydrogenation effect that exists in the heavy petrol is reduced to, a kind of catalyzer of advantageously preferred use is wherein with per unit surface %MoO
3The molybdenum density that weight is represented is higher than 0.07, preferably is higher than 0.10.Catalyzer of the present invention preferably has specific surface less than 190 meters
2/ gram is more preferably less than 180 meters
2/ gram is most preferably less than 150 meters
2/ gram.
After adding one or more elements and shaping of catalyst (when this step uses the mixture that has contained fundamental element to carry out) randomly, first step activates this catalyzer.This activation may be that initial oxidation reduces then, perhaps directly reduction, perhaps only calcining.Calcining step is usually at the about 100-600 of temperature ℃, and preferably 200-450 ℃ is carried out under airflow.
The catalyzer that preferably is its sulfur-bearing form to the small part use.At whole activation step, i.e. can add sulphur before or after calcining or the reduction.Preferably, when adding sulphur or sulfocompound, do not carry out any catalyst oxidation step toward catalyzer.Sulphur or sulfocompound can be not on the spot, promptly implement to add outside the reactor of the inventive method, or on the spot, promptly add in the reactor that the inventive method is used.Under this latter event, reduce under the condition that this catalyzer is preferably described in front, allow the material that contains at least a sulfocompound by vulcanizing then, this sulfocompound is in case decomposition just causes sulphur to be fixed on this catalyzer.This material can be gas or liquid, for example contains H
2The hydrogen of S, or contain the liquid of at least a sulfocompound.
According to prior art embodiments 1 and 2 and embodiments of the invention 3 relatively, can prove meaning of the present invention and advantage.
Embodiment 1 (according to prior art)
Embodiment 1 relates to does not have the middle H that removes
2S, but the sulfur method of hydrodesulfurisationstep step is arranged.
With the aqueous solution of the cobalt of molybdenum that contains the Ammonium Heptamolybdate form and Xiao Suangu, " no excess solution " dipping transition alumina, its aluminum oxide is coccoid, 130 meters of specific surfaces
2/ gram, 0.9 milliliter/gram of pore volume can obtain Hydrobon catalyst A.This catalyzer carries out drying then, and calcines under 500 ℃ of air.The cobalt contents of this sample and molybdenum content are 3%CoO and 10%MoO
3
100 milliliters of catalyst A are put into tubular fixed-bed hydrodesulphurisatioreactors reactors.This catalyzer at first with by 2% just-be the material that the sulphur of dimethyl disulphide forms in the heptane to contact, 3.4 MPas, 350 ℃ of following sulfidizing 4 hours.
The material of handling is a kind of catalytic cracking gasoline, and it begins 50 ℃ of boiling points, 225 ℃ of full boiling points.Its sulphur content is 2000ppm by weight, and bromine index (IBr) is 69 grams/100 grams, and this is corresponding to about 36 weight % alkene.
This material uses catalyst A at pressure 2 MPas, H
2/ HC is than 300 liters/liter and VVH2 hour
-1Handle under the condition.Table 1 shows the influence of temperature to desulfurization degree and olefin saturation performance.
Table 1
| Temperature (℃) | The sulphur content of sweet gasoline (ppm) | Mercaptans content (ppm) | Desulfurization degree (%) | The IBr of sweet gasoline | Alkene saturation exponent (HDO) |
| ????310 | ????41 | ????32 | ????97.9 | ????20.3 | ????70.6 |
| ????320 | ????23 | ????20 | ????98.8 | ????14.7 | ????78.7 |
| ????330 | ????12 | ????11 | ????99.4 | ????10 | ????85.5 |
Using the very high sour gasoline of this class to reach 10ppm sulphur necessary operations condition is high temperature (>310 ℃) and low VVH (2 hours
-1).Under these conditions, might reach desulfurization degree and be higher than 99%, but at this moment the alkene saturation exponent becomes very high (being higher than 85%), this is unfavorable for octane value.
Embodiment 2 (according to prior art)
Embodiment 2 relates to a kind of sulfur method according to prior art, and this method has two hydrodesulfurisationstep step and centre to remove to generate H
2S.
Under condition, use catalyst A than embodiment 1 milder.According to prior art, the desulfurization degree of second hydrodesulfurisationstep step is higher than the desulfurization degree of first step.The material of handling is identical with the material of embodiment 1.
In embodiment 1 reactor, this material mixes with hydrogen and is added to catalyst A.Service temperature is 285 ℃.Other concrete operations condition is listed in table 2.The effluent of reactor outlet contains 239ppm sulphur.These effluents cool off and stripping, so that with hydrogen in the hydrocarbon phase and H
2S separates.According to the operational condition of described second step of listing in the table 2, at this moment steam stripped effluent mixes to reinject with new hydrogen and is equipped with in the reactor of catalyst A.Mass flow should multiply by 1.5 with respect to the flow of first step.The experimental installation that uses comprises that online sulphur content analyses instrument, and this analyser can be measured the sulphur content in the effluent continuously.The temperature of reactor when regulating second step is so that obtain containing the gasoline of 10ppm sulphur.
Table 2
| First step |
| Temperature 1 | ????℃ | ????285 |
| VVH1 | Hour
-1 | ????4 |
| Pressure 1 | Crust | ????20 |
| H
2/HC1
| Rise/liter | ????300 |
| The sulphur in exit | ????ppm | ????239 |
| Outlet IBr | | ????49.9 |
| HDS | ????% | ????88.1 |
| Second step |
| Temperature 2 | ????℃ | ????292 |
| VVH2 | Hour
-1 | ????6 |
| Pressure 2 | Crust | ????20 |
| H
2/HC2
| Rise/liter | ????300 |
| The sulphur in exit | ????ppm | ????10 |
| The mercaptan in exit | ????ppm | ????9 |
| Outlet IBr | | ????36.9 |
| HDS | ????% | ????96.0 |
| |
| Total HDS | ????% | ????99.5 |
| Total HDO | ????% | ????46.6 |
This embodiment shows and comprises that two hydrodesulfurisationstep step and centre remove H
2The method of S, more much higher than the selectivity of the method for implementing a step among the embodiment 1.In fact, gasoline that embodiment 2 produces and the gasoline of embodiment 1 have same sulphur content, but alkene saturation exponent (HDO) here is 46.7%, and embodiment 1 is 85.5%.The process of olefin saturation performance was reduced to minimum when therefore the method for implementing according to embodiment 2 can make and cause hydrogenating desulfurization.
Embodiment 3: the present invention
In this embodiment, with embodiment 2 on the contrary, the desulfurization degree of first step is higher than the desulfurization degree of second step.
The material of handling is identical with embodiment 1 and 2.
This material mixes with hydrogen in the previous reaction device of delivering to catalyst A.Service temperature is 300 ℃.Other operational condition is listed in table 3.The effluent of reactor outlet contains 117ppm sulphur respectively.Operating method is identical with embodiment's 2: these effluents cool off and stripping, so that with hydrogen in the hydrocarbon phase and H
2S separates, and according to the operational condition of listing in the table 3, hydrocarbon phase mixes to reinject with new hydrogen and is equipped with in the reactor of catalyst A.Mass flow should multiply by 1.5 with respect to the flow of first desulfurized step.As among the embodiment 2, attemperation is so that reclaim the gasoline that obtains containing 10ppm sulphur at reactor outlet at last.
Table 3
| First step |
| Temperature 1 | ????℃ | ????300 |
| VVH1 | Hour
-1 | ????4 |
| Pressure 1 | MPa | ????2 |
| H
2/HC1
| Rise/liter | ????300 |
| The sulphur in exit | ????ppm | ????117 |
| Outlet IBr | | ????43.4 |
| HDS | ????% | ????94.2 |
| Second step |
| Temperature 2 | ????℃ | ????264 |
| VVH2 | Hour
-1 | ????6 |
| Pressure 2 | MPa | ????2 |
| H
2/HC2
| Rise/liter | ????300 |
| The sulphur in exit | ????ppm | ????10 |
| The mercaptan in exit | ????ppm | ????6 |
| Outlet IBr | | ????36.8 |
| HDS | ????% | ????91.2 |
| |
| Total HDS | ????% | ????99.5 |
| Total HDO | ????% | ????46.7 |
Method of the present invention, the desulfurization degree that promptly adopts the desulfurization degree of first step to be higher than second step can reach same sulphur content in sweet gasoline, and with the same alkene saturation exponent of prior art by embodiment 2 explanations.Yet the effluent that uses the inventive method to obtain contains the mercaptan than the gasoline that is obtained by embodiment 2 low 30%.Therefore, adopt the inventive method not only can limit the saturability of alkene greatly, but also reduce mercaptans content greatly, significantly reduced the corrodibility of producing gasoline like this.