A kind of method for preparing cyclopentadiene by gas phase depolymerization of dicyclopentadiene

Abstract

The invention provides a method for preparing cyclopentadiene through gas-phase depolymerization of dicyclopentadiene. According to the method, a depolymerizing device is in subsection series connection design and subjected to subsection temperature control; on one hand, the depolymerization time is shortened, and the coking possibility is reduced, so that the service life of the depolymerizing device is prolonged to the maximum, and the depolymerization energy consumption is also reduced by adopting the method provided by the invention; and on the other hand, the DCPD depolymerization rate and CPD yield are further improved by adopting the method provided by the invention and respectively reach 99.9% and 99.5%, especially the CPD yield is also improved by 5% under the condition that the life is prolonged compared with the prior art, and the service life of the depolymerizing device is prolonged to be more than 1200h.

Description

technical field

[0001] The invention discloses a method for preparing cyclopentadiene by gas-phase depolymerization of dicyclopentadiene, which belongs to the field of chemical industry. Background technique

[0002] Dicyclopentadiene and cyclopentadiene are respectively abbreviated as DCPD and CPD in the present invention. CPD is an important by-product of the ethylene industry. It is widely used in rubber, pesticides, resins and other fields, and has high application value. CPD is prone to dimerization reaction at room temperature to generate DCPD. Therefore, when using CPD, it is first necessary to depolymerize DCPD. The depolymerization reaction is:

[0003]

[0004] This reaction is an endothermic reaction, so in order for the reaction to proceed to the right, the heat required for depolymerization must be provided.

[0005] The methods of DCPD depolymerization include liquid phase depolymerization method and gas phase depolymerization method. Liquid-phase depolym...

Examples

example 1

[0073] Using carbon ten with a DCPD content of 80% as a raw material, using the process flow of the present invention, the temperature of the first-stage depolymerizer is controlled at 240°C; the temperature of the second-stage depolymerizer is controlled at 300°C, and the residence time is 7s, n(N 2 ) / n(DCPD)=1:1, a 1200h continuous operation experiment was carried out, and the product analysis results showed that the DCPD depolymerization rate was 99.7%, the CPD yield was 99.0%, and no coke was produced.

example 2

[0075] Using carbon ten with a DCPD content of 80% as a raw material, using the process of the present invention, the temperature control of the first-stage depolymerizer is 270°C; the temperature control of the second-stage depolymerizer is 300°C, and the residence time is 7s, n(N 2 ) / n(DCPD)=1:1, a 1200h continuous operation experiment was carried out, and the product analysis results showed that the DCPD depolymerization rate was 99.9%, the CPD yield was 99.5%, and no coke was produced.

example 3

[0077] Using carbon ten with a DCPD content of 80% as raw material, using the process of the present invention, the temperature control of the first-stage depolymerizer is 240°C; the temperature control of the second-stage depolymerizer is 280°C, and the residence time is 5s, n(N 2 ) / n(DCPD)=1:1, a 1200h continuous operation experiment was carried out, and the product analysis results showed that the DCPD depolymerization rate was 99.1%, the CPD yield was 98.4%, and no coke was produced.

technical field

[0001] The invention discloses a method for preparing cyclopentadiene by gas-phase depolymerization of dicyclopentadiene, which belongs to the field of chemical industry. Background technique

[0002] Dicyclopentadiene and cyclopentadiene are respectively abbreviated as DCPD and CPD in the present invention. CPD is an important by-product of the ethylene industry. It is widely used in rubber, pesticides, resins and other fields, and has high application value. CPD is prone to dimerization reaction at room temperature to generate DCPD. Therefore, when using CPD, it is first necessary to depolymerize DCPD. The depolymerization reaction is:

[0003]

[0004] This reaction is an endothermic reaction, so in order for the reaction to proceed to the right, the heat required for depolymerization must be provided.

[0005] The methods of DCPD depolymerization include liquid phase depolymerization method and gas phase depolymerization method. Liquid-phase depolym...

Examples

example 1

[0073] Using carbon ten with a DCPD content of 80% as a raw material, using the process flow of the present invention, the temperature of the first-stage depolymerizer is controlled at 240°C; the temperature of the second-stage depolymerizer is controlled at 300°C, and the residence time is 7s, n(N 2 ) / n(DCPD)=1:1, a 1200h continuous operation experiment was carried out, and the product analysis results showed that the DCPD depolymerization rate was 99.7%, the CPD yield was 99.0%, and no coke was produced.

example 2

[0075] Using carbon ten with a DCPD content of 80% as a raw material, using the process of the present invention, the temperature control of the first-stage depolymerizer is 270°C; the temperature control of the second-stage depolymerizer is 300°C, and the residence time is 7s, n(N 2 ) / n(DCPD)=1:1, a 1200h continuous operation experiment was carried out, and the product analysis results showed that the DCPD depolymerization rate was 99.9%, the CPD yield was 99.5%, and no coke was produced.

example 3

[0077] Using carbon ten with a DCPD content of 80% as raw material, using the process of the present invention, the temperature control of the first-stage depolymerizer is 240°C; the temperature control of the second-stage depolymerizer is 280°C, and the residence time is 5s, n(N 2 ) / n(DCPD)=1:1, a 1200h continuous operation experiment was carried out, and the product analysis results showed that the DCPD depolymerization rate was 99.1%, the CPD yield was 98.4%, and no coke was produced.

Images