The method of methyl alcohol or dimethyl ether conversion producing light olefins
Technical field
The present invention relates to the method for a kind of methyl alcohol or dimethyl ether conversion producing light olefins.
Technical background
Low-carbon alkene mainly is ethene and propylene, is two kinds of important basic chemical industry raw materials, and its demand is in continuous increase.Usually, ethene, propylene are to produce by petroleum path, but because limited supply of petroleum resources and higher price, the cost of being produced ethene, propylene by petroleum resources constantly increases.In recent years, people begin to greatly develop the technology that alternative materials transforms system ethene, propylene.Wherein, the alternative materials that is used for low-carbon alkene production that one class is important is an oxygenatedchemicals, for example alcohols (methyl alcohol, ethanol), ethers (dme, methyl ethyl ether), ester class (methylcarbonate, methyl-formiate) etc., these oxygenatedchemicalss can be transformed by coal, Sweet natural gas, biomass equal energy source.Some oxygenatedchemicals can reach fairly large production, as methyl alcohol, can be made by coal or Sweet natural gas, and technology is very ripe, can realize up to a million tonnes industrial scale.Because the popularity in oxygenatedchemicals source is added and is transformed the economy that generates low-carbon alkene technology, so by the technology of oxygen-containing compound conversion to produce olefine (OTO), particularly the technology by methanol conversion system alkene (MTO) is subjected to increasing attention.
In the US4499327 patent silicoaluminophosphamolecular molecular sieves catalyzer is applied to methanol conversion system olefin process and studies in great detail, think that SAPO-34 is the first-selected catalyzer of MTO technology.The SAPO-34 catalyzer has very high selectivity of light olefin, and activity is also higher, and can make methanol conversion is the degree that was less than in reaction times of low-carbon alkene 10 seconds, more even reach in the reaction time range of riser tube.
In addition, known in the field, guarantee high selectivity of light olefin, need long-pending a certain amount of carbon of on the SAPO-34 catalyzer, and the agent of MTO technology alcohol ratio is very little, and coking yield is lower, realize catalyst recirculation amount bigger, that control easily, just need in the breeding blanket, the coke content on the catalyzer be controlled at certain level, and then reach the purpose of the average coke content of control reaction zone inner catalyst.Therefore, it is crucial how the average coke content of the catalyzer in the reaction zone being controlled at certain level in the MTO technology.
The method that relates to catalyzer coke content in a kind of MTO of control reactor reaction zone in the US20060025646 patent is the catalyzer part of inactivation to be sent into the breeding blanket make charcoal, and another part decaying catalyst turns back to reaction zone and continues reaction.
Can make in the aforesaid method that the carbon difference that enters between two strands of interior catalyzer of reactor is very big, and contain the catalyzer of more carbon and contain the catalyzer of carbon seldom all unfavorable to the selectivity of low-carbon alkene, there is the problem that the selectivity of product fluctuation is big, the purpose selectivity of product is lower.
Summary of the invention
Technical problem to be solved by this invention is the bad control of revivifier inner catalyst coke-burning regeneration degree that exists in the prior art, the problem of the bad assurance of the average carbon deposit level of catalyst in reactor, and a kind of new methyl alcohol or the method for dimethyl ether conversion producing light olefins are provided.This method is used for the production of low-carbon alkene, has that the convenient control of revivifier inner catalyst coke-burning regeneration degree, the average carbon deposit level of catalyst in reactor are more reasonable, a yield of light olefins advantage of higher in the product.
For solving the problems of the technologies described above, the technical solution used in the present invention is as follows: the method for a kind of methyl alcohol or dimethyl ether conversion producing light olefins, to comprise that methyl alcohol, dme or its mixture are raw material, with SAPO type molecular sieve is catalyzer, raw material generates the effluent that contains ethene, propylene by reaction unit and catalyzer contact reacts, and wherein reaction unit mainly comprises reactor 1, reclaimable catalyst stripper 7, revivifier 9, regenerated catalyst settling section 11 and regenerated catalyst stripper 12; Reactor 1 bottom has opening for feed 2, top has product outlet 5, and inside is provided with gas-solid cyclone separator 3, and reactor settling section 4 bottoms have two catalyst outlets, part catalyzer turns back to reactor 1 bottom, and another part links to each other with reclaimable catalyst stripper 7; Stripper 7 tops have discharge port, link to each other with reactor settling section 4, and the bottom links to each other with revivifier 9 bottoms by pipeline 8; Revivifier 9 bottoms have regenerating medium import 15, and top links to each other with regenerated catalyst settling section 11; Establish cyclonic separator in the regenerated catalyst settling section 11, top has exhanst gas outlet 10, the bottom links to each other with regenerated catalyst stripper 12, regenerated catalyst stripper 12 bottoms have catalyst outlet 13 and link to each other with reactor 1 bottom, regenerated catalyst settling section 11 side lower parts also have catalyst outlet 14 and link to each other in revivifier 9 bottoms with reclaimable catalyst, enter revivifier 9 regeneration, wherein revivifier 9 is a riser tube; Wherein, the gas superficial velocity of interior at least one position of reactor (1) is at least greater than 0.9 meter per second.
In the technique scheme, described SAPO type molecular sieve preferred version is the SAPO-34 molecular sieve; The average coke content preferable range of catalyzer behind the revivifier coke-burning regeneration is less than 6% weight; At least one locational gas superficial velocity is 3~12 meter per seconds in the revivifier, and preferable range is 5~12 meter per seconds; Temperature in the revivifier is between 550~700 ℃, and preferable range is 600~650 ℃; Pressure in the revivifier is counted 0~1MPa with gauge pressure, and preferable range is 0.1~0.3MPa; The temperature of reaction zone is 350~600 ℃, and preferable range is 400~550 ℃, and more preferably scope is 425~500 ℃; Pressure in the reactor is counted 0~1MPa with gauge pressure, and preferable range is 0.1~0.3MPa; The raw material weight air speed is 0.1~20 hour
-1, preferable range is 3~8 hours
-1
Catalyzer behind the inactivation enters the breeding blanket by line of pipes behind stripping, adopt air or air and the mixed gas that reaction is inert gasses is made charcoal at the breeding blanket inner catalyst.Owing to will will control the average carbon deposit level of reaction zone inner catalyst, and easily whole reaction-regeneration system be controlled, need the regeneration level of control breeding blanket inner catalyst.The approach of the degree of making charcoal of control catalyst has the concentration, recovery time, regeneration temperature etc. of oxygen in the control regenerating medium.The degree that the present invention preferably makes charcoal from recovery time control promptly adopts the mobile riser tube that approaches piston flow of gas-solid to carry out the regeneration of catalyzer, makes the reproduction speed of catalyzer be in regenerative power control region.
The average coke content of riser regenerator outlet regenerated catalyst should guarantee with reaction zone in catalyst mix after can reach desired average carbon deposit level.The control of the average coke content of revivifier outlet catalyzer can realize by method of the present invention.If the average coke content of catalyzer of revivifier outlet is higher than institute's required value, can all or part ofly turns back to the revivifier inlet and proceed regeneration.The regenerated catalyst that reaches the carbon content requirement enters the reaction zone of reactor by the catalyst transport pipeline behind stripping, with the existing catalyst mix in the reaction zone, reach required average carbon deposit level, and contact with raw material.
In reactor feed, can also add the common charging of a certain proportion of thinner non-imposedly, thinner can be low-carbon alkanes (methane, ethane, propane etc.), low-carbon alcohol (ethanol, n-propyl alcohol, Virahol, propyl carbinol, isopropylcarbinol etc.), CO, nitrogen, water vapour, C4 hydrocarbon, mononuclear aromatics etc., wherein, preferred low-carbon alkanes, low-carbon alcohol, water vapour, more preferably low-carbon alcohol, water vapour, most preferably be water vapour, the amount of thinner and the volume ratio of raw material can be 0.1~10: regulate in 1 scope.
By controlling regeneration level among the present invention, adjust the method for reaction zone coke content, can also in the scope of broad, adjust the ethene that generates in the reaction zone and the ratio of propylene.The remarkable method of adjusting ethylene/propene in the MTO reaction mainly contains the temperature of adjusting reaction zone, the carbon deposit level of adjusting reaction zone etc., the method of the invention can be when adjusting temperature of reaction, adjust the average coke content of reaction zone, thereby can in a big way, adjust the ethylene/propene ratio.
Adopt method of the present invention, can be implemented in the degree that the revivifier inner control is made charcoal, make regenerated catalyst keep certain carbon content to enter reaction zone, thereby reach the purpose of the average coke content of control reaction zone inner catalyst.When the average coke content of the catalyzer in the reaction zone is controlled suitable value, can make that yield of light olefins reaches maximum value.Therefore, method of the present invention can improve the yield of low-carbon alkene in the reaction process, and easy to operate, is easy to control.
Adopt technical scheme of the present invention: the average coke content of the catalyzer behind the revivifier coke-burning regeneration is less than 6% (weight); The fluidized-bed reactor temperature of reaction is 350~600 ℃, and the reaction weight space velocity is 0.1~20 hour
-1, be 0~1MPa in the gauge pressure reaction pressure, the gas superficial velocity of at least one position is at least greater than 0.9 meter per second in the reaction zone; The riser regenerator regeneration temperature is 550~700 ℃, and the pressure in the revivifier is counted 0~1MPa with gauge pressure, and at least one locational gas superficial velocity is 3~12 meter per seconds in the revivifier; Catalyzer is that yield of light olefins can reach 77.02% (weight), has obtained better technical effect under the SAPO type molecular sieve condition.
Description of drawings
Fig. 1 is the schematic flow sheet of the method for the invention.
Among Fig. 1,1 is fluidized-bed reactor; 2 is the feeding line of fluidized-bed reactor bottom; 3 is cyclonic separator; 4 is the settling section of fluidized-bed reactor; 5 is the outlet line of fluidized-bed reactor; 6 enter the line of pipes of stripper for catalyst in reactor; 7 strippers; 8 enter the line of pipes of revivifier for the stripping rear catalyst; 9 is revivifier; 10 is flue gas discharge opening; 11 is the regenerated catalyst settling section; 12 is the stripper of regenerated catalyst; 13 return the line of pipes of reaction zone for regenerated catalyst; 14 return the line of pipes of breeding blanket for regenerated catalyst; 15 is the opening for feed of revivifier 9.
Raw material enters the reactor 1 of reaction unit through pipeline 2, contact with catalyst and react, gas-solid mixture enters reaction unit after separating fast catalyst sedimentation section 4, partially catalyzed agent and gas product are after cyclone separator 3 separates, and gas product enters follow-up centrifugal station through outlet line 5. Under the cyclonic separation and sedimentation under catalyst enter stripper 7 through pipeline 6, stripping goes out the gas product that catalyst carries, enter the charging aperture 15 of the regenerator 9 of regenerating unit through feed-line 8 through steam stripped catalyst, also enter regenerator 9, the carbon deposit on the catalyst and regenerating medium generation oxidation reaction with the regenerating medium contact. The gas-solid mixture that comes out from regenerator 9 enters the settling section 11 of regenerating unit, and flue gas is discharged by pipeline 10 through cyclonic separation, and sedimentation or isolated catalyst enter reactor 1 by pipeline 13 after stripper 12. In regenerator, by control regeneration parameter, such as recovery time, regeneration temperature etc., can reach the purpose of control regeneration level, if the phosphorus content of regenerated catalyst does not reach the required carbon level that contains, catalyst after the regeneration can be mixed into regenerator by pipeline 14 and decaying catalyst, further coke-burning regeneration.
The invention will be further elaborated below by embodiment, but be not limited only to present embodiment.
Specific embodiment
[embodiment 1~4]
In small-sized circulating fluid bed reaction device, reaction-regeneration system flow process form is identical with Fig. 1.Revivifier 9 adopts riser tubes, and lift gas is an air, and 600 ℃ of regeneration temperatures are adjusted the average coke content of regenerated catalyst by changing gas superficial velocity in the riser regenerator.Reactor 1 adopts fast fluidized bed, and gas superficial velocity is 1.2 meter per seconds, and temperature of reaction is 425 ℃, and pure methanol feeding, methyl alcohol weight space velocity are 3 hours
-1, be 0MPa in gauge pressure reaction and regeneration pressure.The thief hole of regenerator and spent agent lays respectively on pipeline 13 and the pipeline 8, and infrared carbon sulphur high speed analysis instrument is adopted in the analysis of carbon content on the catalyzer.The internal circulating load of catalyzer is remained on a rational value, make that system is stable, control is convenient.At first guarantee catalyst inventory and controlling level in the reactor, come the internal circulating load of control catalyst by the turnover flow (valve control) of catalyzer in control pipeline 14 and the pipeline 6.Catalyzer adopts the SAPO-34 modified catalyst of spray-dried moulding.The reactor outlet product adopts online gas chromatographic analysis, and experimental result sees Table 1.
Table 1
Embodiment |
Breeding blanket gas phase superfacial velocity, meter per second |
The spent agent coke content, % (weight) |
The average coke content of reaction zone inner catalyst, % (weight) |
The regenerator coke content, % (weight) |
Ethene carbon back yield, % (weight) |
Propylene carbon back yield, % (weight) |
Ethene+propylene carbon back yield, % (weight) |
Embodiment 1 |
3.2 |
8.8 |
2.8 |
1.1 |
36.67 |
37.78 |
74.45 |
Embodiment 2 |
5.1 |
8.5 |
5.2 |
2.5 |
40.28 |
35.76 |
76.04 |
Embodiment 3 |
6.2 |
8.1 |
5.8 |
3.1 |
42.82 |
33.89 |
76.71 |
Embodiment 4 |
12.6 |
7.9 |
6.7 |
5.7 |
45.27 |
28.68 |
73.95 |
[embodiment 5~7]
According to embodiment 2 described conditions, just change the regeneration temperature of revivifier 9, experimental result sees Table 2.
Table 2
Parameter |
Regeneration temperature, ℃ |
The average coke content of reaction zone inner catalyst, % (weight) |
The regenerator coke content, % (weight) |
Ethene carbon back yield, % (weight) |
Propylene carbon back yield, % (weight) |
Ethene+propylene carbon back yield, % (weight) |
Embodiment 5 |
550 |
5.7 |
2.8 |
42.76 |
33.9 |
76.66 |
Embodiment 6 |
650 |
5.1 |
2.3 |
40.13 |
35.89 |
76.02 |
Embodiment 7 |
700 |
4.8 |
1.9 |
38.97 |
35.98 |
74.95 |
[embodiment 8~12]
According to embodiment 3 described conditions, just change the temperature of reaction of reactor 1, experimental result sees Table 3.
Table 3
Parameter |
Temperature of reaction, ℃ |
The spent agent coke content, % (weight) |
Ethene carbon back yield, % (weight) |
Propylene carbon back yield, % (weight) |
Ethene+propylene carbon back yield, % (weight) |
Embodiment 8 |
350 |
7.7 |
34.72 |
36.64 |
71.36 |
Embodiment 9 |
400 |
7.9 |
39.43 |
34.12 |
73.55 |
Embodiment 10 |
500 |
8.5 |
45.35 |
30.98 |
76.33 |
Embodiment 11 |
550 |
8.7 |
48.32 |
24.17 |
72.49 |
Embodiment 12 |
600 |
9.1 |
51.67 |
20.32 |
71.99 |
[embodiment 13~15]
According to embodiment 3 described conditions, just change the methyl alcohol weight space velocity, experimental result sees Table 4.
Table 4
Parameter |
The methyl alcohol weight space velocity, hour
-1 |
Ethene carbon back yield, % (weight) |
Propylene carbon back yield, % (weight) |
Ethene+propylene carbon back yield, % (weight) |
Embodiment 13 |
0.12 |
40.19 |
30.42 |
70.61 |
Embodiment 14 |
8.11 |
43.15 |
33.87 |
77.02 |
Embodiment 15 |
19.45 |
44.26 |
27.68 |
71.94 |
[embodiment 16~18]
According to embodiment 3 described conditions, reactor 1 adopts same press operation with revivifier 9, changes the pressure of reactor, revivifier, and experimental result sees Table 5.
Table 5
Parameter |
The pressure of reactor and revivifier, MPa |
Ethene carbon back yield, % (weight) |
Propylene carbon back yield, % (weight) |
Ethene+propylene carbon back yield, % (weight) |
Embodiment 16 |
0.1 |
40.87 |
33.56 |
74.43 |
Embodiment 17 |
0.3 |
38.97 |
32.96 |
71.93 |
Embodiment 18 |
1.0 |
35.79 |
31.78 |
67.57 |
[embodiment 19~21]
According to embodiment 3 described conditions, change the catalyst type in the reactor 1, experimental result sees Table 6.
Table 6
Parameter |
Catalyst type |
Ethene carbon back yield, % (weight) |
Propylene carbon back yield, % (weight) |
Ethene+propylene carbon back yield, % (weight) |
Embodiment 19 |
SAPO-11 |
6.97 |
21.56 |
28.53 |
Embodiment 20 |
SAPO-18 |
41.43 |
30.65 |
72.08 |
Embodiment 21 |
SAPO-56 |
25.65 |
21.78 |
47.43 |
[embodiment 22~23]
According to embodiment 3 described conditions, change type of feed, experimental result sees Table 7.
Table 7
Parameter |
Type of feed |
The volume ratio of methyl alcohol and dme |
Ethene carbon back yield, % (weight) |
Propylene carbon back yield, % (weight) |
Ethene+propylene carbon back yield, % (weight) |
Embodiment 22 |
Dme |
? |
42.78 |
33.79 |
76.57 |
Embodiment 23 |
Methyl alcohol+dme |
1∶1 |
42.81 |
33.82 |
76.63 |
[embodiment 24]
According to embodiment 4 described conditions, regenerated catalyst is divided into two portions, wherein a part is passed through pipeline 13 Returning reactors 1 behind stripping, another part returns the inlet of revivifier 9 by pipeline 14 without stripping, with enter revivifier 9 regeneration after reclaimable catalyst mixes, the ratio of the catalyst quality flow rate in pipeline 13 and the pipeline 14 is 2: 1.Experimental result is: ethene carbon back yield is that 42.78% (weight) propylene carbon back yield is 33.65% (weight) ethene+propylene carbon back yield 76.43% (weight).
Obviously, adopt method of the present invention, can realize the make charcoal control of degree of revivifier 9 inner catalysts, thereby the average coke content of catalyzer in the further controlling reactor 1, finally reach the purpose that improves yield of light olefins, have bigger technical superiority, can be used in the industrial production of low-carbon alkene.