Method for coupling MTO (methanol to olefin) process with process of preparing ethylene by cracking naphtha steam

Abstract

The invention relates to a method for coupling an MTO (methanol to olefin) process with a process of preparing ethylene by cracking naphtha steam, and aims at mainly solving the problems that an existing coupling technology is unreasonable in process design, large in investment and high in operating cost. According to the technical scheme, the method for coupling the MTO process with the process of preparing ethylene by cracking naphtha steam is adopted; an MTO product gas enters a coarse separation tower after being compressed and dried; coarse separation tower top stream including components below C2 and a part of C3 components enters a deethanization tower in the process of preparing ethylene by cracking naphtha steam; coarse separation tower kettle stream including residual C3 components and components over C4 enters a depropanization tower in the MOT separation process; the depropanization tower kettle stream enters a debutanization tower in the process of preparing ethylene by cracking naphtha steam, so that the problems are well solved, and the method can be applied to production of light olefins.

Description

technical field

[0001] The invention relates to a coupling method of an MTO process and a naphtha steam cracking process for producing ethylene. Background technique

[0002] Low-carbon olefins, namely ethylene and propylene, are two important basic chemical raw materials. At present, ethylene and propylene are mainly produced through petroleum routes, such as naphtha steam cracking technology to produce ethylene and propylene. US 20070083071 discloses a process for producing ethylene and propylene by catalytic cracking of hydrocarbons. The hydrocarbon raw materials are converted into products including low-carbon olefins in a catalytic cracking furnace, and then the product stream is separated into C2~C3 alkanes, C2~ For the three streams of C3 olefins and C4+ hydrocarbons, C2-C3 alkanes are returned to the tubular cracking furnace for thermal cracking, and C4+ hydrocarbons are returned to the catalytic cracking furnace for catalytic cracking, and finally ethylene and propy...

Examples

Embodiment 1

[0022] The naphtha steam cracking ethylene unit adopts the pre-deethanization process, the ethylene production capacity is 1.2 million tons / year, the mass ratio of propylene to ethylene in the cracking gas is 0.47, and the methanol treatment scale of the newly added MTO unit is 1.8 million tons / year In 2009, the mass ratio of ethylene to propylene in MTO product gas was 1.5. Using the coupling method of the present invention, the operating conditions of the rough separation tower are: temperature is -10°C, pressure is 1.5MPaG. The obtained polymerization-grade ethylene has a purity of ≥99.95 mol%, and the polymerization-grade propylene has a purity of ≥99.6 mol%. The output distribution data of ethylene and propylene are shown in Table 1. Compared with Comparative Example 1, the input of naphtha is reduced by 1.2766 million tons / year, the production of propylene is increased by 79,600 tons / year, the investment of MTO plant project is saved by 788 million yuan, and the price di...

Embodiment 2

[0026] The naphtha steam cracking ethylene unit adopts the pre-deethanization process, the ethylene production capacity is 1.1 million tons / year, the mass ratio of propylene to ethylene in the cracking gas is 0.47, and the methanol treatment scale of the newly added MTO unit is 1.8 million tons / year In 2009, the mass ratio of ethylene to propylene in MTO product gas was 1.5. Using the coupling method of the present invention, the operating conditions of the rough separation tower are: temperature is -10°C, pressure is 1.5MPaG. The obtained polymerization-grade ethylene has a purity of ≥99.95 mol%, and the polymerization-grade propylene has a purity of ≥99.6 mol%. The output distribution data of ethylene and propylene are shown in Table 1. Compared with Comparative Example 2, the input of naphtha is reduced by 1.2766 million tons / year, the production of propylene is increased by 79,600 tons / year, the investment of MTO plant project is saved by 788 million yuan, and the price di...

Embodiment 3

[0030] The naphtha steam cracking ethylene unit adopts the pre-deethanization process, the ethylene production capacity is 1 million tons / year, the mass ratio of propylene to ethylene in the cracking gas is 0.47, and the methanol treatment scale of the newly added MTO unit is 1.8 million tons / year In 2009, the mass ratio of ethylene to propylene in MTO product gas was 0.8. Using the coupling method described in the present invention, the operating conditions of the crude separation tower are: temperature is -20°C, and pressure is 0.6MPaG. The obtained polymerization-grade ethylene has a purity of ≥99.95 mol%, and the polymerization-grade propylene has a purity of ≥99.6 mol%. The output distribution data of ethylene and propylene are shown in Table 1. Compared with Comparative Example 3, the input of naphtha is reduced by 850,500 tons / year, the production of propylene is increased by 210,100 tons / year, the investment of MTO plant project is saved by 411 million yuan, and the pr...

technical field

[0001] The invention relates to a coupling method of an MTO process and a naphtha steam cracking process for producing ethylene. Background technique

[0002] Low-carbon olefins, namely ethylene and propylene, are two important basic chemical raw materials. At present, ethylene and propylene are mainly produced through petroleum routes, such as naphtha steam cracking technology to produce ethylene and propylene. US 20070083071 discloses a process for producing ethylene and propylene by catalytic cracking of hydrocarbons. The hydrocarbon raw materials are converted into products including low-carbon olefins in a catalytic cracking furnace, and then the product stream is separated into C2~C3 alkanes, C2~ For the three streams of C3 olefins and C4+ hydrocarbons, C2-C3 alkanes are returned to the tubular cracking furnace for thermal cracking, and C4+ hydrocarbons are returned to the catalytic cracking furnace for catalytic cracking, and finally ethylene and propy...

Examples

Embodiment 1

[0022] The naphtha steam cracking ethylene unit adopts the pre-deethanization process, the ethylene production capacity is 1.2 million tons / year, the mass ratio of propylene to ethylene in the cracking gas is 0.47, and the methanol treatment scale of the newly added MTO unit is 1.8 million tons / year In 2009, the mass ratio of ethylene to propylene in MTO product gas was 1.5. Using the coupling method of the present invention, the operating conditions of the rough separation tower are: temperature is -10°C, pressure is 1.5MPaG. The obtained polymerization-grade ethylene has a purity of ≥99.95 mol%, and the polymerization-grade propylene has a purity of ≥99.6 mol%. The output distribution data of ethylene and propylene are shown in Table 1. Compared with Comparative Example 1, the input of naphtha is reduced by 1.2766 million tons / year, the production of propylene is increased by 79,600 tons / year, the investment of MTO plant project is saved by 788 million yuan, and the price di...

Embodiment 2

[0026] The naphtha steam cracking ethylene unit adopts the pre-deethanization process, the ethylene production capacity is 1.1 million tons / year, the mass ratio of propylene to ethylene in the cracking gas is 0.47, and the methanol treatment scale of the newly added MTO unit is 1.8 million tons / year In 2009, the mass ratio of ethylene to propylene in MTO product gas was 1.5. Using the coupling method of the present invention, the operating conditions of the rough separation tower are: temperature is -10°C, pressure is 1.5MPaG. The obtained polymerization-grade ethylene has a purity of ≥99.95 mol%, and the polymerization-grade propylene has a purity of ≥99.6 mol%. The output distribution data of ethylene and propylene are shown in Table 1. Compared with Comparative Example 2, the input of naphtha is reduced by 1.2766 million tons / year, the production of propylene is increased by 79,600 tons / year, the investment of MTO plant project is saved by 788 million yuan, and the price di...

Embodiment 3

[0030] The naphtha steam cracking ethylene unit adopts the pre-deethanization process, the ethylene production capacity is 1 million tons / year, the mass ratio of propylene to ethylene in the cracking gas is 0.47, and the methanol treatment scale of the newly added MTO unit is 1.8 million tons / year In 2009, the mass ratio of ethylene to propylene in MTO product gas was 0.8. Using the coupling method described in the present invention, the operating conditions of the crude separation tower are: temperature is -20°C, and pressure is 0.6MPaG. The obtained polymerization-grade ethylene has a purity of ≥99.95 mol%, and the polymerization-grade propylene has a purity of ≥99.6 mol%. The output distribution data of ethylene and propylene are shown in Table 1. Compared with Comparative Example 3, the input of naphtha is reduced by 850,500 tons / year, the production of propylene is increased by 210,100 tons / year, the investment of MTO plant project is saved by 411 million yuan, and the pr...

Images