CN102276381A

CN102276381A - Method for improving selectivity of light olefins prepared from conversion of oxygenated compound

Info

Publication number: CN102276381A
Application number: CN2010101997211A
Authority: CN
Inventors: 王洪涛; 齐国祯; 俞志楠; 陈伟
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2010-06-11
Filing date: 2010-06-11
Publication date: 2011-12-14
Anticipated expiration: 2030-06-11
Also published as: CN102276381B

Abstract

The invention relates to a method for improving selectivity of light olefins prepared from conversion of an oxygenated compound, and a purpose of the present invention is mainly to solve the problem of poor average carbon deposition level of a catalyst in a reactor in the prior art. According to the present invention, the method for improving the selectivity of the light olefins prepared from conversion of the oxygenated compound is adopted. The method mainly comprises the following steps that: a) raw materials of the oxygenated compound contact a molecular sieve catalyst in a fluidized bed reactor to generate product stream I containing the light olefins and the carbon deposited catalyst; b) the product stream I is subjected to gas-solid separation, then the gas-phase product containing the light olefins flows from the top of the reactor, and the solid-phase carbon deposited catalyst enters the sedimentation segment of the reactor; c) the carbon deposited catalyst in the sedimentation segment of the reactor is divided into at least two parts, wherein the first part enters the reactor through a circulating pipeline of the reactor, the second part enters a regenerator through a spent pipeline; d) the carbon deposited catalyst is regenerated through the regenerator, and then enters the sedimentation segment of the regenerator to ensure the height of the catalyst bed in the sedimentation segment of the regenerator, such that the catalyst can naturally flow in the sedimentation segment of the reactor after steam stripping; e) one part of the catalyst in the sedimentation segment of the regenerator returns to the regenerator through a circulating pipeline of the regenerator. With the technical scheme of the present invention, the regenerator is adopted as the lift pipe, such that the problem in the prior art is solved better; the method can be applicable for the industrial production of the light olefins prepared through conversion of the oxygenated compound.

Description

Improve optionally method of converting oxygen-containing compound to low-carbon olefins

Technical field

The present invention relates to optionally method of a kind of raising converting oxygen-containing compound to low-carbon olefins.

Background technology

Low-carbon alkene is defined as ethene and propylene here, is two kinds of important basic chemical industry raw materials, and its demand is in continuous increase.Ethene, propylene mainly are to make by petroleum path traditionally, 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 substitute energy transformation technology, and as the technology of oxygen-containing compound conversion to produce olefine (OTO), oxygenatedchemicals comprises methyl alcohol, ethanol, dme, methyl ethyl ether, methylcarbonate etc.Have many technology to can be used to produce oxygenatedchemicals, raw material comprises coal, Sweet natural gas, biomass etc.As methyl alcohol, can make by coal or Sweet natural gas, 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.

For the MTO technology, long-pending a certain amount of carbon can effectively improve the selectivity of low-carbon alkene in the reaction product on the SAPO-34 catalyzer, and has the catalyst carbon deposit weight range an of the best to make that the selectivity of low-carbon alkene is the highest.Therefore, will enter the certain coke content of control on the catalyzer of reactor, and then reach the purpose of the higher selectivity of light olefin of control.In addition, for the catalyzer with best coke content, the carbon deposit on the granules of catalyst is average more, and the selectivity of low-carbon alkene is just high more in the product.Therefore, it is crucial how the catalyzer coke content in the reaction zone evenly 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, cause the problem that the fluctuation of low-carbon alkene selectivity of product is big, the purpose selectivity of product is lower.

Summary of the invention

Technical problem to be solved by this invention is to have the not good problem of the average carbon deposit level of catalyst in reactor in the prior art, and optionally method of a kind of new raising converting oxygen-containing compound to low-carbon olefins is provided.This method is used for the production of low-carbon alkene, has that the catalyst in reactor carbon deposit is average, a selectivity of light olefin 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, a kind of raising converting oxygen-containing compound to low-carbon olefins is method optionally, mainly may further comprise the steps: a) raw material of oxygenatedchemicals contacts with molecular sieve catalyst in fluidized-bed reactor, generates the product logistics I that comprises low-carbon alkene and carbon deposited catalyst; B) the logistics I is after gas solid separation, and the gas-phase product that contains low-carbon alkene flows out from reactor head, and its solid phase carbon deposited catalyst enters the reactor settling section; C) carbon deposited catalyst is divided into two portions at least in the reactor settling section, and first part enters reactor through the reactor cycles pipeline, and second section enters revivifier through pipeline to be generated; D) carbon deposited catalyst enters the revivifier settling section after revivifier regeneration, guarantees that revivifier settling section inner catalyst bed height makes catalyzer flow into the reactor settling section naturally behind stripping; E) a part of catalyzer returns revivifier through the revivifier circulation line in the revivifier settling section; Wherein, revivifier is a riser tube.

In the technique scheme, the oxygenatedchemicals in the raw material is at least a in methyl alcohol or the dme, and described molecular sieve catalyst is selected from SAPO type molecular sieve.Oxygenatedchemicals in the raw material is preferably methyl alcohol, and SAPO type molecular screening is from the SAPO-34 molecular sieve.The temperature of reactor is 350～600 ℃, and the pressure in the reactor is counted 0～1MPa with gauge pressure, and the raw material weight air speed is 0.1～20 hour ^-1Between; Temperature in the revivifier is between 550～700 ℃, and revivifier is interior to be 0～1MPa in gauge pressure pressure.The temperature of reactor is preferably 420～500 ℃, and the pressure in the reactor is preferably 0.1～0.3MPa in gauge pressure, and the raw material weight air speed is preferably 3～8 hours ^-1Temperature in the revivifier is preferably 600～650 ℃, is preferably 0.1～0.3MPa in gauge pressure pressure in the revivifier.Carbon deposition catalyst is in mass flux ratio first part in the settling section: second section=1: 0.01～2; Carbon deposition catalyst is in the preferred first part of mass flux ratio in the settling section: second section=1: 0.05～0.5.The average coke content of reactor settling section inner catalyst is 1～9%; The average coke content of reactor settling section inner catalyst is 2～6%.

Catalyzer in the reactor settling section enters revivifier by pipeline to be generated behind stripping, adopt the mixed gas of air or air and rare gas element to make charcoal at the breeding blanket inner catalyst.The catalyzer that catalyzer after the process regeneration and circulation line come enters reactor bottom, must make that the catalyst carbon difference in the reactor is bigger, carbon deposit is inhomogeneous, even the average coke content of catalyzer reaches best coke content, can not make the selectivity of low-carbon alkene reach maximum.In addition, catalyst temperature after the regeneration is higher, and the catalyst temperature that circulation line comes is lower, and the temperature of raw material is lower, three strands of bigger materials of the temperature difference mix the temperature distributing disproportionation that must make in the reactor and spare in reactor, increased the difficulty of temperature of reactor control.

Adopt method of the present invention, can be by the revivifier circulation line so that the degree that carbon deposited catalyst is made charcoal in the revivifier is easy to control, the catalyst transport after the regeneration is mixed with a large amount of carbon deposited catalyst elder generations in settling vessel, enters reactor through circulation line then.Adopt this method, no matter be that catalyzer adopts the mode of holomorphosis or the mode of incomplete regen-eration in the revivifier, directly feed reactor with respect to regenerated catalyst in the prior art, can make that the catalyst carbon deposit in the reactor is more even, thereby realize the purpose of the best coke content of controlling reactor inner catalyst, can make that selectivity of light olefin reaches maximum value.In addition, the catalyzer after the regeneration mixes with carbon deposition catalyst earlier again and mixes with raw material, makes that the interior temperature distribution of mixing post-reactor is more even, is easy to control.Therefore, method of the present invention can effectively improve the selectivity of low-carbon alkene in the reaction process, and easy to operate, is easy to control.

Adopt technical scheme of the present invention: the oxygenatedchemicals in the raw material is at least a in methyl alcohol or the dme, and described molecular sieve catalyst is a SAPO type molecular sieve.The temperature of reactor is 350～600 ℃, and the pressure in the reactor is counted 0～1MPa with gauge pressure, and the raw material weight air speed is 0.1～20 hour ^-1Between.Temperature in the revivifier is between 550～700 ℃, and revivifier is interior to be 0～1MPa in gauge pressure pressure; Carbon deposition catalyst is in mass flux ratio first part in the settling section: second section=1: 0.01～2; The average coke content of reactor settling section inner catalyst is 1～9%.The carbon back yield of ethene+propylene reaches as high as 80.38% weight, has obtained better technical effect.

Description of drawings

Fig. 1 is the schematic flow sheet of the method for the invention.

Among Fig. 1,1 is the reactor settling section; 2 is the reactor cycles pipeline; 3 is the feeding line of fluidized-bed reactor bottom; 4 is fluidized-bed reactor; 5 are the regenerating medium inlet; 6 is riser regenerator; 7 is the revivifier settling section; 8 is stripper; 9 are the regeneration pipeline; 10 is the revivifier circulation line; 11 is pipeline to be generated.

Raw material enters the fluidized-bed reactor 4 of reaction unit from the feeding line 3 of fluidized-bed reactor bottom, contact with the catalyzer of reactor cycles pipeline 2 and react, gas-solid mixture enters the reactor settling section 1 of reaction unit behind sharp separation, gaseous products enters follow-up centrifugal station after deviating from catalyzer through cyclonic separator; Catalyzer first part catalyzer in the reactor settling section enters fluidized-bed reactor 4 through reactor cycles pipeline 2, and second section enters riser regenerator 6 through the catalyzer merging of pipeline 11 to be generated and revivifier circulation line 10; The carbon deposited catalyst that enters riser regenerator 6 enters revivifier settling section 7 after contacting with the regenerating medium of regenerating medium inlet 5 and burning, a part of catalyzer advances stripper 8 strippings after regeneration pipeline 9 is delivered to reactor settling section 1 in the revivifier settling section 7, and a part of catalyzer enters riser regenerator 6 through the catalyzer merging of revivifier circulation line 10 and pipeline 11 to be generated.Making charcoal of carbon deposited catalyst is easy to control in revivifier, can regulate the coke content of revivifier settling section inner catalyst by control revivifier circulation line.It is more even with the carbon deposit of carbon deposited catalyst mixing rear catalyst that regenerated catalyst enters the reactor settling section, thereby can effectively improve the selectivity of low-carbon alkene.

The invention will be further elaborated below by embodiment, but be not limited only to present embodiment.

Embodiment

[embodiment 1～3]

On reaction unit as shown in Figure 1, reactor adopts fast fluidized bed, temperature of reaction is 450 ℃, adopt the feeding manner of methyl alcohol, dme, methyl alcohol+dme respectively, the raw material weight air speed is 5 hours-1, be 0.01MPa in gauge pressure reaction and regeneration pressure, revivifier adopts riser tube, regenerating medium is an air, regeneration temperature is 650 ℃, the thief hole of regenerator and spent agent lays respectively at regeneration pipeline 9 and pipeline to be generated 11, and infrared carbon sulphur high speed analysis instrument is adopted in the analysis of carbon content on the catalyzer.The coke content of control reclaimable catalyst is 5.9% (weight percent), the coke content of regenerated catalyst is 05% (weight percent), carbon deposition catalyst in the settling section is controlled to be first part in mass flux ratio: second section=1: 0.1 makes that system is stable, control is convenient.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

Parameter	Type of feed	Methyl alcohol: dme (weight ratio)	Ethene carbon back yield, % (weight)	Propylene carbon back yield, % (weight)	Ethene+propylene carbon back yield, % (weight)
						Embodiment 1	Methyl alcohol	-	43.14	34.25	77.39
Embodiment 2	Dme	-	43.49	33.78	77.27
						Embodiment 3	Methyl alcohol+dme	1∶1	43.85	33.81	77.66

[embodiment 4～6]

According to embodiment 1 described condition, just change the type of catalyzer, experimental result sees Table 2.

Table 2

Parameter	Catalyst type	Ethene carbon back yield, % (weight)	Propylene carbon back yield, % (weight)	Ethene+propylene carbon back yield, % (weight)
					Embodiment 4	SAPO-11	8.52	23.12	31.64
Embodiment 5	SAPO-18	40.79	28.35	69.14
					Embodiment 6	SAPO-56	28.66	22.69	51.35

[embodiment 7～10]

According to embodiment 1 described condition, just change temperature of reactor, experimental result sees Table 3.

Table 3

Parameter	Temperature of reactor, ℃	Ethene carbon back yield, % (weight)	Propylene carbon back yield, % (weight)	Ethene+propylene carbon back yield, % (weight)
					Embodiment 7	350	25.29	26.57	51.86
Embodiment 8	420	40.63	34.11	74.74
					Embodiment 9	500	48.26	32.12	80.38
Embodiment 10	600	42.68	20.74	63.41

[embodiment 11～14]

According to embodiment 1 described condition, 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 11	0.15	41.97	31.48	73.45
Embodiment 12	3.05	43.17	33.62	76.79
					Embodiment 13	8.16	43.85	33.65	77.50
Embodiment 14	19.40	44.89	27.74	72.63

[embodiment 15～17]

According to embodiment 1 described condition, just change regenerator temperature, experimental result sees Table 5.

Table 5

Parameter	Regeneration temperature, ℃	The regenerator coke content, % (weight)	Ethene carbon back yield, % (weight)	Propylene carbon back yield, % (weight)	Ethene+propylene carbon back yield, % (weight)
						Embodiment 15	550	1.50	44.99	32.69	77.68
Embodiment 16	600	1.15	44.07	33.58	77.65
						Embodiment 17	700	0.01	42.49	33.69	76.18

[embodiment 18～20]

According to embodiment 1 described condition, reactor and revivifier adopt same press operation, change the pressure of reactor, revivifier, and experimental result sees Table 6.

Table 6

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 18	0.1	41.88	33.69	75.57
Embodiment 19	0.3	39.78	32.86	73.64
					Embodiment 20	1	36.56	31.69	68.25

[embodiment 21～24]

According to embodiment 1 described condition, just change the ratio of settling section two portions carbon deposition catalyst mass rate, experimental result sees Table 7.

Table 7

Parameter	First part: second section (mass flux ratio)	Ethene carbon back yield, % (weight)	Propylene carbon back yield, % (weight)	Ethene+propylene carbon back yield, % (weight)
					Embodiment 21	1∶0.02	20.33	10.01	30.34
Embodiment 22	1∶0.05	44.54	30.20	74.74
					Embodiment 23	1∶0.5	40.44	35.37	75.81
Embodiment 24	1∶2	40.30	35.04	75.34

[embodiment 25～28]

According to embodiment 1 described condition, just change the coke content of reclaimable catalyst, experimental result sees Table 8.

Table 8

Parameter	The spent agent coke content, % (weight)	Ethene carbon back yield, % (weight)	Propylene carbon back yield, % (weight)	Ethene+propylene carbon back yield, % (weight)
					Embodiment 25	1.00	39.04	35.48	74.52
Embodiment 26	2.10	40.87	35.02	75.89
					Embodiment 27	7.60	40.36	30.14	70.50
Embodiment 28	9.20	25.89	20.64	46.53

[comparative example 1～3]

Reaction unit is changed, and the catalyzer after the regeneration is not transported to the reactor settling section, but directly enters reactor from reactor bottom, and all according to embodiment 1,15,17 described conditions, experimental result sees Table 9 for all the other.

Table 9

Parameter	Regeneration temperature, ℃	The regenerator coke content, % (weight)	Ethene carbon back yield, % (weight)	Propylene carbon back yield, % (weight)	Ethene+propylene carbon back yield, % (weight)
						Comparative example 1	650	0.50	42.44	33.91	76.35
Comparative example 2	550	1.50	43.09	33.66	76.75
						Comparative example 3	700	0.01	41.63	33.69	75.32

Obviously, adopt method of the present invention, effectively improved oxygenatedchemicals transforms producing light olefins in the presence of molecular sieve catalyst selectivity, have bigger technical superiority, can be used in the industrial production of low-carbon alkene.

Claims

1. one kind is improved optionally method of converting oxygen-containing compound to low-carbon olefins, mainly may further comprise the steps:

A) raw material of oxygenatedchemicals contacts with molecular sieve catalyst in fluidized-bed reactor, generates the product logistics I that comprises low-carbon alkene and carbon deposited catalyst;

B) the logistics I is after gas solid separation, and the gas-phase product that contains low-carbon alkene flows out from reactor head, and its solid phase carbon deposited catalyst enters the reactor settling section;

C) carbon deposited catalyst is divided into two portions at least in the reactor settling section, and first part enters reactor through the reactor cycles pipeline, and second section enters revivifier through pipeline to be generated;

D) carbon deposited catalyst enters the revivifier settling section after revivifier regeneration, guarantees that revivifier settling section inner catalyst bed height makes catalyzer flow into the reactor settling section naturally behind stripping;

E) a part of catalyzer returns revivifier through the revivifier circulation line in the revivifier settling section;

Wherein, revivifier is a riser tube.

2. according to the described raising converting oxygen-containing compound to low-carbon olefins of claim 1 method optionally, it is characterized in that oxygenatedchemicals in the raw material is at least a in methyl alcohol or the dme, described molecular sieve catalyst is selected from SAPO type molecular sieve.

3. according to the described raising converting oxygen-containing compound to low-carbon olefins of claim 2 method optionally, it is characterized in that the oxygenatedchemicals in the raw material is a methyl alcohol, SAPO type molecular screening is from the SAPO-34 molecular sieve.

4. according to the described raising converting oxygen-containing compound to low-carbon olefins of claim 1 method optionally, the temperature that it is characterized in that reactor is 350～600 ℃, and the pressure in the reactor is counted 0～1MPa with gauge pressure, and the raw material weight air speed is 0.1～20 hour ^-1Between; Temperature in the revivifier is between 550～700 ℃, and revivifier is interior to be 0～1MPa in gauge pressure pressure.

5. according to the described raising converting oxygen-containing compound to low-carbon olefins of claim 4 method optionally, the temperature that it is characterized in that reactor is 420～500 ℃, and the pressure in the reactor is counted 0.1～0.3MPa with gauge pressure, and the raw material weight air speed is 3～8 hours ^-1Temperature in the revivifier is 600～650 ℃, and revivifier is interior to be 0.1～0.3MPa in gauge pressure pressure.

6. according to the described raising converting oxygen-containing compound to low-carbon olefins of claim 1 method optionally, it is characterized in that in the settling section that carbon deposition catalyst is in mass flux ratio first part: second section=1: 0.01～2.

7. according to the described raising converting oxygen-containing compound to low-carbon olefins of claim 6 method optionally, it is characterized in that in the settling section that carbon deposition catalyst is in mass flux ratio first part: second section=1: 0.05～0.5.

8. according to the described raising converting oxygen-containing compound to low-carbon olefins of claim 1 method optionally, the average coke content that it is characterized in that reactor settling section inner catalyst is 1～9%.

9. described according to Claim 8 raising converting oxygen-containing compound to low-carbon olefins is method optionally, and the average coke content that it is characterized in that reactor settling section inner catalyst is 2～6%.