Start-up method for reaction-regeneration unit used to prepare light olefins from methanol

Patent metadata

Field	Value
Publication number	US-9233350-B2
Application number	US-201313736892-A
Country	US
Kind code	B2
Filing date	Jan 8, 2013
Priority date	Jan 10, 2012
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

The invention provides a start-up method for a reaction-regeneration unit for preparing light olefins from methanol, which comprises: (a) heating a regenerator with an auxiliary combustion chamber and a reactor with a start-up furnace; (b) charging a catalyst into the regenerator and reactor; (c) closing a spent catalyst slide valve and a regenerated catalyst slide valve after the reactor reaches about 350° C. or more; (d) feeding methanol to the reactor after the dense phase stage of the regenerator reaches about 350° C. or more; (e) opening the spent catalyst slide valve and introducing a carbon deposited catalyst from the reactor to the regenerator after the dense phase stage reaches about 400° C. or more and the average amount of carbon deposits on the catalyst in the reactor reaches about 2.5% or more; (f) raising the regenerator to above about 580° C.; and (g) stopping the start-up furnace and auxiliary combustion chamber.

First claim

The invention claimed is:

1. A method for starting-up a process for producing light olefins from methanol in a reaction-regeneration unit, comprising the following steps:
preheating the reaction-regeneration unit having a reactor and a regenerator prior to introducing a methanol-containing feedstock into the reactor, wherein the preheating step comprises steps (a), (b), and (c):

(a) heating the regenerator using hot air until a dense phase stage of the regenerator reaches a temperature in a range from about 350° C. to about 550° C., and heating the reactor using a superheated steam having a temperature of about 400° C. to about 550° C.;
(b) charging a first portion of a catalyst into the regenerator and charging a second portion of the catalyst into the reactor;
(c) closing a spent catalyst slide valve in a spent catalyst slope tube and a regenerated catalyst slide valve in a regenerated catalyst slope tube when the temperature of the reactor reaches at least about 350° C.;
injecting a first back-flushing gas into the spent catalyst slope tube so that a density of the catalyst in the spent catalyst slope tube is less than about 100 kg/m 3 ; and
injecting a second back-flushing gas into the regenerated catalyst slope tube so that a density of the catalyst in the regenerated catalyst slope tube is less than about 100 kg/m 3 ;

(d) introducing the methanol-containing feedstock into the reactor when a dense phase stage of the regenerator reaches a temperature of at least about 350° C.; establishing a circulation of the catalyst in the reactor; and forming carbon deposits on the catalyst;
(e) establishing a circulation of the catalyst between the reactor and the regenerator when a temperature of the dense phase stage of the regenerator reaches at least about 400° C. and an average amount of carbon deposits on the catalyst in the reactor reaches at least about 2.5%; and
(f) burning the carbon deposits on the catalyst in the regenerator to release heat so as to heat the regenerator to a temperature above about 580° C.

2. The method according to claim 1 , wherein the hot air is heated in an auxiliary combustion chamber and the superheated steam is heated in a start-up furnace.

3. The method according to claim 1 , wherein a fuel for combustion in the auxiliary combustion chamber is diesel oil, fuel gas, or a mixture thereof.

4. The method according to claim 1 , wherein the catalyst comprises an aluminosilicophosphate molecular sieve.

5. The method of claim 1 , wherein the first back-flushing gas is injected into the spent catalyst slope tube upstream of the spent catalyst slide valve and the second back-flushing gas is injected into the regenerated catalyst slope tube upstream of the regenerated catalyst slide valve.

6. The method of claim 1 , wherein the first back-flushing gas and the second back-flushing gas is independently chosen from stream, nitrogen, fuel gas, or a combination thereof.

7. The method according to claim 1 , wherein step (e) further comprises the following sub-steps:
opening the spent catalyst slide valve;
reducing or stopping the first back-flushing gas so as to allow the carbon deposited catalyst from the reactor to enter the regenerator through the spent catalyst slope tube;
opening the regenerated catalyst slide valve; and
reducing or stopping the second back-flushing gas so as to allow the regenerated catalyst from the regenerator to enter the reactor through the regenerated catalyst slope tube.

8. The method according to claim 1 , wherein in step (d) the circulation of the catalyst in the reactor comprises circulating a portion of the catalyst through an outer circulating tube having an inlet and an outlet connected to the reactor.

9. The method according to claim 8 , wherein the outer circulating tube is configured to receive heat from an external source.

10. The method according to claim 2 , further comprising step (g):
(g) shutting down the start-up furnace and the auxiliary combustion chamber when the reactor reaches a temperature of at least about 480° C. and the regenerator reaches a temperature of at least about 650° C.

11. The method according to claim 10 , wherein steps (a) to (g) are completed in about two hours to about four hours.

Assignees

• China Petroleum & Chemical
• Shanghai Res Inst Petrochemical Technology Sinopec

Inventors

• Qi Guozhen
• Zhong Siqing
• Yu Zhinan
• Jin Yongming

Classifications

• B01J8/1872 Primary

  Details of the fluidised bed reactor (B01J8/1836 takes precedence) · CPC title

• B01J8/26

  with two or more fluidised beds, e.g. reactor and regeneration installations · CPC title

• B01J8/008 Primary

  Details of the reactor or of the particulate material; Processes to increase or to retard the rate of reaction (B01J8/0285, B01J8/067, B01J8/087, B01J8/1836 take precedence) · CPC title