Fluidized bed reactor and process for producing olefins from oxygenates

Patent metadata

Field	Value
Publication number	US-9403735-B2
Application number	US-201214124502-A
Country	US
Kind code	B2
Filing date	May 30, 2012
Priority date	Jun 8, 2011
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

The present invention provides a fluidized bed reactor and its use for producing olefins from oxygenates, the fluidized bed reactor comprises: a reaction zone located in the lower portion of the fluidized bed reactor and comprising a lower dense phase zone and an upper riser, wherein the dense phase zone and the riser are connected with each other transitionally; a separation zone located in the upper portion of the fluidized bed reactor and comprising a settling chamber, a fast gas-solid separation means, a cyclone and a gas collecting chamber, wherein the riser extends upwardly into the separation zone and is connected at its outlet with the inlet of the fast gas-solid separation means, the fast gas-solid separation means is connected at its outlet with the inlet of the cyclone via a fast gas passage, the cyclone is connected at its outlet with the gas collecting chamber, and the gas collecting chamber is located below the reactor outlet and connected therewith; and a catalyst recycle line for recycling the catalyst from the settling chamber back to the dense phase zone, a catalyst withdrawl line for withdrawing the deactivated catalyst from the settling chamber and/or the dense phase zone to the catalyst regeneration means, and a catalyst return line for returning the regenerated catalyst from the catalyst regeneration means to the dense phase zone.

First claim

The invention claimed is:

1. A fluidized bed reactor, comprising:
a reaction zone located in a lower portion of the fluidized bed reactor and comprising a lower dense phase zone and an upper riser, wherein the lower dense phase zone and the upper riser are connected with each other transitionally;
a separation zone located in an upper portion of the fluidized bed reactor and comprising a settling chamber, a fast gas-solid separator, a cyclone and a gas collecting chamber, wherein the upper riser extends upwardly into the separation zone and an outlet of the upper riser is connected with an inlet of the fast gas-solid separator, an outlet of the fast gas-solid separator is connected with an inlet of the cyclone via a fast gas passage, an outlet of the cyclone is connected with the gas collecting chamber, and the gas collecting chamber is located below a reactor outlet and connected with the reactor outlet; and
a catalyst recycle line configured to recycle a catalyst from the settling chamber back to the lower dense phase zone, a catalyst withdrawal line configured to withdraw a deactivated catalyst from at least one of the settling chamber and the lower dense phase zone to a catalyst regenerator, and a catalyst return line configured to return a regenerated catalyst from the catalyst regenerator to the lower dense phase zone,
wherein the fluidized bed reactor is suitable for producing an olefin from an oxygenate,
the lower dense phase zone has a height to diameter ratio of from 0.5 to 10,
the upper riser has a height to diameter ratio of from 2 to 20,
a diameter ratio of the lower dense phase zone to the upper riser is from 2 to 10, and
the fast gas passage is configured such that a stream resides in the fast gas passage for not more than 5 seconds.

2. The fluidized bed reactor according to claim 1 ,
wherein the lower dense phase zone comprises an inner portion configured to remove reaction heat and/or prevent backmixing of gas and solid.

3. The fluidized bed reactor according to claim 1 ,
wherein the height to diameter ratio of the lower dense phase zone is from 0.6 to 8,
the height to diameter ratio of the upper riser is from 3 to 15, and
the diameter ratio of the lower dense phase zone to the upper riser is from 2.5 to 8.

4. The fluidized bed reactor according to claim 3 ,
wherein the height to diameter ratio of the lower dense zone is from 0.8 to 5,
the height to diameter ratio of the upper rise is from 4 to 10, and
the diameter ratio of the lower dense phase zone to the upper riser is from 3 to 6.

5. The fluidized bed reactor according to claim 1 ,
wherein the settling chamber is located in a lower portion of the separation zone such that a catalyst separated in the separation zone is collected in the settling chamber, and
the settling chamber comprises a stripping gas distributor in an inside of the settling chamber such that a stripping gas is introduced to strip the catalyst, and a stripped mixture guiding line at an upper side of the settling chamber such that the stripped mixture is transferred to the cyclone to be separated.

6. The fluidized bed reactor according to claim 1 , wherein the fast gas-solid separator is selected from the group consisting of a vortex type fast gas-solid separator, an ejection type fast gas-solid separator, an inverse L type fast gas-solid separator, a T type fast gas-solid separator, a multi-tube type fast gas-solid separator, and a rotary arm type fast gas-solid separator.

7. The fluidized bed reactor according to claim 1 ,
wherein the cyclone comprises at least one group of cyclones, and
each group of cyclones comprises one, two or three cyclones in series.

8. The fluidized bed reactor according to claim 1 ,
wherein the fast gas passage is configured such that the stream resides in the fast gas passage for not more than 4 seconds.

9. The fluidized bed reactor according to claim 8 ,
wherein the fast gas passage is configured such that the stream resides in the fast gas passage for not more than 3 seconds.

10. A process for producing an olefin from an oxygenate with the fluidized bed reactor according to claim 1 , the process comprising:
introducing a feed stream comprising an oxygenate and a diluent into the lower dense phase zone in the lower portion of the fluidized bed reactor via a feed inlet distributor, such that the feed stream is reacted in the presence of a catalyst and that a part of a feed is converted to a lower olefin and a part of the catalyst is deactivated due to carbon deposition thereon;
directing a reaction mixture comprising the lower olefin, unreacted feed and the catalyst from the lower dense phase zone upwardly into the upper riser, such that substantially all of the unreacted feed is further converted to the lower olefin in the presence of the catalyst and that a riser effluent primarily comprising the lower olefin and the catalyst is produced;
entering the riser effluent directly into the separation zone in the upper portion of the fluidized bed reactor, wherein the riser effluent is first entered into the fast gas-solid separator such that most of the catalyst is separated, entered into the cyclone via the fast gas passage such that remaining catalyst is separated, entered into the gas collecting chamber, and then exited through the reactor outlet, and all the separated catalyst falls into the settling chamber in the lower portion of the separation zone; and
recycling a part of the catalyst from the settling chamber back to the lower dense phase zone via the catalyst recycle line, withdrawing a part of the deactivated catalyst from at least one of the settling chamber and the lower dense phase zone to the catalyst regenerator via the catalyst withdrawal line such that the deactivated catalyst is regenerated in the catalyst regenerator, and then returning a part of the regenerated catalyst from the catalyst regenerator to the lower dense phase zone via the catalyst return line;
wherein, when passing the lower dense phase zone, the stream has a superficial gas velocity of from 0.1 to 2 m/s, and a residence time of from 0.5 to 20 seconds,
when passing the upper riser, the stream has a superficial gas velocity of from 2 to 20 m/s, and a residence time of from 0.3 to 5 seconds, and
when passing the fast gas passage, the stream has a residence time of not more than 5 seconds.

11. The process according to claim 10 , further comprising at least one of:
removing reaction heat; and
preventing backmixing of gas and solid by the inner portion in the lower dense phase zone.

12. The process according to claim 10 ,
wherein, when passing the lower dense phase zone, the stream has a superficial gas velocity of from 0.2 to 1.5 m/s, and a residence time of from 1 to 15 seconds,
when passing the upper riser, the stream has a superficial gas velocity of from 4 to 18 m/s, and a residence time of from 0.4 to 4 seconds, and
when passing the fast gas passage, the stream has a residence time of not more than 4 seconds.

13. The process according to claim 12 ,
wherein, when passing the lower dense phase zone, the stream has a superficial gas velocity of from 0.3 to 1.2 m/s, and a residence time of from 2 to 10 seconds, and
when passing the upper riser, the stream has a superficial gas velocity of from 5 to 15 m/s, and a residence time of from 0.5 to 3 seconds.

14. The process according to claim 10 , further comprising:
introducing a stripping gas via the stripping gas distributor into the settling chamber to strip the catalyst, wherein the stripping gas is nitrogen or steam; and
passing a stripped gas mixture to the cyclone via a stripped mixture

Assignees

• Wei Fei
• Wei Xiaobo
• Wang Yao
• Zhu Chang
• Fude (Beijing) Chemical & Ind Co Ltd
• Univ Tsinghua

Inventors

• Wei Fei
• Wei Xiaobo
• Wang Yao
• Zhu Chang

Classifications

• B01J8/28 Primary

  the one above the other · CPC title

• C07C11/02

  Alkenes · CPC title

• B01J8/0055

  using cyclones · CPC title

• Y02P20/584

  Recycling of catalysts · CPC title

• C07C1/20

  starting from organic compounds containing only oxygen atoms as heteroatoms · CPC title