A method for producing a terpolymer polypropylene from a coal to olefin byproduct

Abstract

The present application relates to a kind of coal to olefin by-product production ternary copolymerization polypropylene method, belong to carbon four separation and olefin polymerization technical field.The method comprises the following steps: S1, with coal as raw material synthesis methanol;S2, with the methanol obtained in step S1 as raw material, by fluidized bed reactor, the C4-C6 component separated out in the process of converting methanol into propylene;S3, using the way of rectification, from the C4-C6 component obtained in step S2 1-butene is separated;S4, with the 1-butene separated in step S3 and propylene, ethylene, hydrogen, silane, triethylaluminum, isopropanol as raw material, using Ziegler-Natta catalyst, under the condition of 2.4-3.0MPa, 70-80 ℃ in catalytic reactor generates propylene ethylene butane ternary copolymer polypropylene.The present application expands the source of 1-butene, also for can to polypropylene market continuously provide high-performance polypropylene product lay foundation.

Description

Technical Field

[0001] This invention relates to the fields of C4 separation and olefin polymerization technology, and in particular to a method for producing ternary copolymer polypropylene from coal-to-olefins byproducts. Background Technology

[0002] Ethylene-propylene-butene terpolymer polypropylene is a multiphase copolymer obtained by copolymerizing ethylene and 1-butene as monomers with propylene. Compared with propylene-ethylene binary copolymer polypropylene, the addition of ethylene and 1-butene disrupts the regularity of the polypropylene molecular chain to some extent, thereby lowering the melting temperature of polypropylene. This results in a final film with better low-temperature heat-sealing performance, higher transparency, better anti-blocking properties, and better rigidity and toughness. It can be widely used in high-quality packaging fields such as food, stationery, cosmetics, and clothing, and has a larger market demand.

[0003] Currently, the main sources of 1-butene used in the production of ethylene-propylene-butadiene terpolymer polypropylene include: steam cracking of heavy oil, ethylene dimerization, and mixed C4 enrichment from refinery cracking units. These sources are mainly concentrated in the petroleum refining sector and are relatively singular. However, due to the scarcity of petroleum resources, the insufficient supply of 1-butene for production greatly limits the production of ethylene-propylene-butadiene terpolymer polypropylene. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for producing ternary copolymer polypropylene (TCPP) from coal-to-olefins by-products, which solves the technical problem that the production yield of ethylene-propylene-butene ternary copolymer polypropylene is limited due to the shortage of petroleum resources and insufficient sources of 1-butene.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0008] In a first aspect, embodiments of the present invention provide a method for producing ternary copolymer polypropylene from coal-to-olefins byproducts, comprising the following steps:

[0009] S1. Methanol is synthesized from coal.

[0010] S2. Using the methanol obtained in step S1 as raw material, methanol is converted into propylene through a fluidized bed reactor, and the C4-C6 components by-products of the methanol-propylene conversion process are separated by distillation.

[0011] The C4-C6 components include isobutane, n-butane, cis-2-butene, trans-2-butene, and 1-butene;

[0012] S3. Separate 1-butene from the C4-C6 fraction obtained in step S2 by distillation;

[0013] S4. Using 1-butene obtained in step S3, along with propylene, ethylene, hydrogen, silane, triethylaluminum, and isopropanol as raw materials, a Ziegler-Natta catalyst is used to react in a catalytic reactor at 2.4-3.0 MPa and 70-80℃ to produce propylene-ethylene-butyl terpolymer polypropylene.

[0014] Optionally, in step S1, the method for synthesizing methanol from coal includes: heating coal to 1200-1400℃ using air, oxygen, or steam at a reaction pressure of 5.0-6.5 MPa, causing the coal to decompose into a gas containing carbon monoxide, carbon dioxide, hydrogen, nitric oxide, and methane; and then synthesizing methanol from the generated gas at a pressure of 5-8 MPa and a temperature of 220-260℃ under the action of a copper-based catalyst.

[0015] Optionally, in step S2, the method for separating the C4-C6 components includes: reacting the methanol obtained in step S1 with a ZSM-5 molecular sieve catalyst in an MCR reactor to form a fluidized bed, generating light hydrocarbon gas; the generated light hydrocarbon gas enters a quench tower for dust removal and cooling, and then is sent to a water washing tower for countercurrent washing to remove oxygen-containing organic matter entrained in the light hydrocarbon gas; the treated gas is compressed and condensed by a compressor, and acidic gases in the gas are removed by a water washing tower and an alkaline washing tower; the gas is then compressed and condensed again by a compressor, dried to remove water, and distilled to obtain the C4-C6 components.

[0016] Optionally, the temperature inside the MCR reactor is 350-400℃ and the pressure is 200-220kPa; the temperature inside the quench tower is 90-95℃ and the pressure is 0.06-0.09MPa; and the temperature of the gas inside the water washing tower is 40-45℃ and the pressure is 0.08-0.10MPa.

[0017] Optionally, in step S3, the system for separating 1-butene includes a light component separation tower, an isobutane separation tower, a C4 separation tower, and a butene separation tower;

[0018] After the C4-C6 components are distilled in the light component separation tower, the bottom component of the light component separation tower enters the C4 separation tower for distillation, and the top component of the C4 separation tower enters the butene separation tower. After distillation in the butene separation tower, 1-butene is collected from the top of the butene separation tower.

[0019] Optionally, the top temperature of the light component separation tower is -28.8 to -30°C, the bottom temperature is 50 to 52°C, and the condenser is cooled with propylene at -40 to -45°C; the top temperature of the C4 separation tower is 65 to 70°C, the bottom temperature is 95 to 100°C; and the top temperature of the butene separation tower is -25 to -28°C, the bottom temperature is -2 to -5°C.

[0020] Preferably, the top temperature of the light component separation tower is -28.8°C and the bottom temperature is 50.3°C, and the condenser is cooled with -40°C propylene. The top temperature of the C4 separation tower is 65°C and the bottom temperature is 100°C. The top temperature of the butene separation tower is -25°C and the bottom temperature is -2°C.

[0021] Optionally, the bottom outlet of the light component separation tower is connected to a condenser, and the top outlet of the butene separation tower is connected to a condenser.

[0022] Optionally, in step S4, the system for preparing propylene-ethylene-butyl terpolymer polypropylene includes a polymerization reactor, a second cyclone separator, a degassing tank, and a purification chamber.

[0023] 1-Butene, propylene, ethylene, hydrogen, silane, triethylaluminum, and isopropanol are fed into the polymerization reactor. The materials are mixed evenly in the polymerization reactor by stirring. A catalyst is added to the polymerization reactor to generate propylene-ethylene-butadiene ternary copolymer polypropylene powder. The generated propylene-ethylene-butadiene ternary copolymer polypropylene powder is sequentially separated by the second cyclone separator, the degassing tank, and the purification silo. The separated propylene gas is recovered to the recovery unit, and the separated propylene-ethylene-butadiene ternary copolymer polypropylene powder is extruded into granules.

[0024] Optionally, the system for preparing propylene-ethylene-butyl terpolymer polypropylene further includes a first cyclone separator, a first filter, a compressor, a circulating pump, a condenser, and a second filter;

[0025] The remaining propylene gas after the reaction in the polymerization reactor is separated by the first cyclone separator, and the propylene-ethylene-butadiene ternary copolymer polypropylene powder carried out is separated and returned to the polymerization reactor. The separated propylene gas is filtered by the first filter and then condensed in the condenser. The condensed propylene liquid is returned to the polymerization reactor by the circulation pump, or the condensed propylene liquid is compressed by the delivery compressor and then returned to the polymerization reactor.

[0026] Optionally, the propylene gas recovered in the recovery unit is fed into the polymerization reactor for recycling.

[0027] (III) Beneficial Effects

[0028] The beneficial effects of this invention are as follows: This invention provides a method for producing ternary copolymer polypropylene from coal-to-olefins byproducts, using coal as raw material, thus solving the problem of insufficient 1-butene production due to the scarcity of crude oil resources. This invention expands the sources of 1-butene, broadening the raw material sources for the production of propylene-ethylene-butane ternary copolymer polypropylene, and laying the foundation for a continuous supply of high-performance ternary copolymer polypropylene to the polypropylene market, resulting in better economic efficiency.

[0029] This invention extracts high-purity 1-butene from the C4-C6 components byproduct of fluidized bed methanol-to-propylene technology via distillation. The process is simple, and the recovery rate of 1-butene can reach over 96%, with a purity of over 99%. It can be used in the subsequent production of propylene-ethylene-butene terpolymer polypropylene.

[0030] In the process of producing propylene-ethylene-butyl terpolymer polypropylene from 1-butene of the present invention, the propylene-ethylene-butyl terpolymer polypropylene and propylene gas can be efficiently separated, resulting in high purity propylene-ethylene-butyl terpolymer polypropylene. The separated propylene gas can be recycled and reused, which is economical and environmentally friendly. Attached Figure Description

[0031] Figure 1 A process flow diagram for separating 1-butene from C4-C6 components.

[0032] [Attached image captions]

[0033] 1: Light component separation tower; 2: Isobutane separation tower; 3: C4 separation tower; 4: Butene separation tower; 5: Polymerization reactor; 6: First cyclone separator; 7: First filter; 8: Compressor; 9: Circulating pump; 10: Condenser; 11: Second filter; 12: Second cyclone separator; 13: Degassing tank; 14: Purification chamber. Detailed Implementation

[0034] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0036] Example 1

[0037] This embodiment provides a method for producing ternary copolymer polypropylene from coal-to-olefins byproducts, including the following steps:

[0038] S1. Coal-to-methanol process:

[0039] Under a reaction pressure of 5.0-6.5 MPa, coal is heated to 1200-1400℃ using air, oxygen, or steam, causing the coal to decompose into gases containing carbon monoxide, carbon dioxide, hydrogen, nitric oxide, and methane. The generated gases are then used to synthesize crude methanol at a pressure of 5-8 MPa, a temperature of 220-260℃, and with an NC306 copper-based catalyst.

[0040] S2. Separation of C4-C6 components byproducts from the methanol-to-propylene process using the FMTP (fluidized bed methanol-to-propylene) process:

[0041] The crude methanol obtained in step S1 is reacted with ZSM-5 molecular sieve catalyst powder in an MCR reactor (380℃, 220kPa) to form a fluidized bed, generating light hydrocarbons (the main components of which are ethylene, propylene, C1-C7 light hydrocarbons, hydrogen, and water). The olefins generated in this reactor, excluding propylene, are then reacted again in an EBTP (butadiene-pentylene to propylene) reactor (440℃, 220kPa) to generate propylene, thereby improving the overall yield of propylene. The fluidized ZSM-5 molecular sieve catalyst after the reaction is transported to a regenerator (air, 700℃) to restore its activity, and then returned to the MCR and EBTP reactors. The catalyst is thus circulated among the three reactors.

[0042] The generated process gas is mixed and enters the quench tower for dust removal and cooling (94℃, 0.09MPa). Then, it is sent to the water washing tower (process gas 40℃, 0.08MPa) for countercurrent washing to remove oxygen-containing organic matter entrained in the process gas. Subsequently, the low-pressure process gas undergoes four-stage compression and condensation by the compressor. Between the second and third stages of the compressor (second stage outlet pressure 0.65MPa, 40℃), a water washing tower and an alkaline washing tower are installed to further remove acidic gases from the process gas. Between the third and fourth stages (third stage outlet pressure 1.4MPa, 40℃), a dryer is installed to remove the moisture generated after condensation. Between the third and fourth stages, two distillation towers are installed to remove C4-C6 components (including isobutane, n-butane, cis-2-butene, trans-2-butene, and 1-butene, etc.) from the process gas, and the C4-C6 components are collected. The processed process gas is sent from the fourth stage outlet of the compressor (2.9MPa) to the distillation section to remove other components from the process gas except for propylene, and obtain a polymer-grade propylene product with a purity >99.6%.

[0043] S3. Extracting 1-butene from the C4-C6 fraction:

[0044] The C4-C6 fractions collected in step S2 are separated to extract 1-butene, as shown in the process flow below. Figure 1 As shown.

[0045] This embodiment uses four distillation columns to separate 1-butene from the C4-C6 fraction. In the figure, 1 is the light component separation column, 2 is the isobutane separation column, 3 is the C4 separation column, and 4 is the butene separation column. Light component separation column 1 and isobutane separation column 2 are used to separate light components, while C4 separation column 3 and butene separation column 4 are used to separate heavy components. Specifically, the C4-C6 fraction first enters the light component separation column 1. The top fraction of the light component separation column 1 enters the isobutane separation column 2. The top fraction of the isobutane separation column 2 separates the light component isobutane, and the bottom fraction of the isobutane separation column 2 is recycled within the isobutane separation column 2 to separate isobutane. The bottom component of the light component separation tower 1 enters the C4 separation tower 3. n-Butane is separated from the bottom of the C4 separation tower 3, and the top component of the C4 separation tower 3 enters the butene separation tower 4. 2-Butene is separated from the bottom of the butene separation tower 4, and 1-Butene is separated from the top of the butene separation tower 4. The recovery rate of 1-Butene can reach 96%, and the purity can reach 99%.

[0046] S4, 1-butene synthesize propylene-ethylene-butene terpolymer polypropylene:

[0047] The process flow for synthesizing propylene-ethylene-butene terpolymer polypropylene from 1-butene is as follows: Figure 1 As shown in the figure. In the figure, 5 is the polymerization reactor, 6 is the first cyclone separator, 7 is the first filter, 8 is the compressor, 9 is the circulating pump, 10 is the condenser, 11 is the second filter, 12 is the second cyclone separator, 13 is the degassing tank, and 14 is the purification chamber.

[0048] 1-Butene, propylene, ethylene, hydrogen, silane, triethylaluminum, and isopropanol are pumped into polymerization reactor 5. The materials are stirred to ensure uniform mixing in reactor 5. A Zieglie-Natta catalyst is added to reactor 5. Under conditions of 2.4-3.0 MPa(G) and 70-80℃, propylene-ethylene-butadiene terpolymer polypropylene powder is generated in reactor 5. The generated propylene-ethylene-butadiene terpolymer polypropylene powder is separated by a second cyclone separator 12. The separated propylene gas is recovered to the recovery unit, and the separated powder enters a degassing tank 13 for further propylene gas removal. Then, in the purification silo 14, trace amounts of propylene gas entrained in the powder are further removed under nitrogen stripping. The removed propylene gas is recovered to the recovery unit. The purified powder is then conveyed to an extruder for granulation. The propylene gas separated by the second cyclone separator 12 is filtered by a second filter 11 and collected in the recovery unit.

[0049] After the reaction in the polymerization reactor 5, the remaining propylene gas is separated by the first cyclone separator 6, which separates the propylene-ethylene-butadiene ternary copolymer polypropylene powder and returns it to the polymerization reactor 5. The separated propylene gas is filtered by the first filter 7 and then condensed in the condenser 10. The condensed propylene liquid is returned to the feed inlet of the polymerization reactor 5 by the circulation pump 9, or the condensed propylene liquid is compressed by the compressor 8 and then returned to the feed inlet of the polymerization reactor 5.

[0050] In this embodiment, the main components of the packing material in the first filter 7 and the second filter 11 are alumina smooth spherical adsorbent and silica gel desiccant, which are mainly used to remove COS, CO2 and moisture.

[0051] The propylene recovered in the recycling unit can be recycled back into the system or discharged for other uses.

[0052] In this embodiment, the synthesis of propylene-ethylene-butyl terpolymer polypropylene from 1-butene can efficiently produce propylene-ethylene-butyl terpolymer polypropylene. Simultaneously, propylene gas and the propylene-ethylene-butyl terpolymer polypropylene can be separated, resulting in a yield of 98% and a purity of 99%. Furthermore, the propylene can be separated and recycled, making it more economical and environmentally friendly.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing ternary copolymer polypropylene from coal-to-olefins byproducts, characterized in that, The steps include the following: S1. Methanol is synthesized from coal. S2. Using the methanol obtained in step S1 as raw material, methanol is converted into propylene through a fluidized bed reactor, and the C4-C6 components by-products of the methanol-propylene conversion process are separated by distillation. The C4-C6 components include isobutane, n-butane, cis-2-butene, trans-2-butene, and 1-butene; S3. Separate 1-butene from the C4-C6 fraction obtained in step S2 by distillation; The system for separating 1-butene includes a light component separation tower (1), an isobutane separation tower (2), a C4 separation tower (3), and a butene separation tower (4). The light component separation tower (1) and the isobutane separation tower (2) are used to separate light components, and the C4 separation tower (3) and the butene separation tower (4) are used to separate heavy components. After the C4-C6 components are distilled by the light component separation tower (1), the bottom component of the light component separation tower (1) enters the C4 separation tower (3) for distillation, and the top component of the C4 separation tower (3) enters the butene separation tower (4). After distillation by the butene separation tower (4), 1-butene is collected from the top of the butene separation tower (4). S4. Using 1-butene obtained in step S3, as well as propylene, ethylene, hydrogen, silane, triethylaluminum, and isopropanol as raw materials, a propylene-ethylene-butane terpolymer polypropylene is generated in a catalytic reactor under conditions of 2.4-3.0 MPa and 70-80℃ using a Ziegler-Natta catalyst.

2. The method for producing ternary copolymer polypropylene from coal-to-olefins byproducts according to claim 1, characterized in that, In step S1, the method for synthesizing methanol from coal includes: heating coal to 1200-1400℃ using air, oxygen, or steam at a reaction pressure of 5.0-6.5 MPa, causing the coal to decompose into a gas containing carbon monoxide, carbon dioxide, hydrogen, nitric oxide, and methane; then synthesizing methanol from the generated gas at a pressure of 5-8 MPa and a temperature of 220-260℃ using a copper-based catalyst.

3. The method for producing ternary copolymer polypropylene from coal-to-olefins byproducts according to claim 1, characterized in that, In step S2, the method for separating the C4-C6 components includes: reacting the methanol obtained in step S1 with a ZSM-5 molecular sieve catalyst in an MCR reactor to form a fluidized bed, generating light hydrocarbon gas; the generated light hydrocarbon gas enters a quench tower for dust removal and cooling, and then is sent to a water washing tower for countercurrent washing to remove oxygen-containing organic matter entrained in the light hydrocarbon gas; the treated gas is compressed and condensed by a compressor, and acidic gases are removed from the gas by a water washing tower and an alkaline washing tower; the gas is then compressed and condensed again by a compressor, dried to remove water, and distilled to obtain the C4-C6 components.

4. The method for producing ternary copolymer polypropylene from coal-to-olefins byproducts according to claim 3, characterized in that, The temperature inside the MCR reactor is 350-400℃ and the pressure is 200-220kPa; the temperature inside the quench tower is 90-95℃ and the pressure is 0.06-0.09MPa; the temperature of the gas inside the water washing tower is 40-45℃ and the pressure is 0.08-0.10MPa.

5. The method for producing ternary copolymer polypropylene from coal-to-olefins byproducts according to claim 1, characterized in that, The top temperature of the light component separation tower (1) is -28.8~-30℃, the bottom temperature is 50-52℃, and the condenser is cooled with propylene at -40~-45℃. The top temperature of the C4 separation tower (3) is 65-70℃, the bottom temperature is 95-100℃, and the top temperature of the butene separation tower (4) is -25~-28℃, the bottom temperature is -2~-5℃.

6. The method for producing ternary copolymer polypropylene from coal-to-olefins byproducts according to claim 1, characterized in that, The bottom outlet of the light component separation tower (1) is connected to the condenser, and the top outlet of the butene separation tower (4) is connected to the condenser.

7. The method for producing ternary copolymer polypropylene from coal-to-olefins byproducts according to claim 1, characterized in that, In step S4, the system for preparing propylene-ethylene-butyl terpolymer polypropylene includes a polymerization reactor (5), a second cyclone separator (12), a degassing tank (13), and a purification chamber (14). 1-Butene, propylene, ethylene, hydrogen, silane, triethylaluminum, and isopropanol are fed into the polymerization reactor (5). The materials are mixed evenly in the polymerization reactor (5) by stirring. A catalyst is added to the polymerization reactor (5) to generate propylene-ethylene-butyl ternary copolymer polypropylene powder. The generated propylene-ethylene-butyl ternary copolymer polypropylene powder is sequentially separated by the second cyclone separator (12), the degassing tank (13), and the purification chamber (14). The separated propylene gas is recovered to the recovery unit, and the separated propylene-ethylene-butyl ternary copolymer polypropylene powder is extruded into granules.

8. The method for producing ternary copolymer polypropylene from coal-to-olefins byproducts according to claim 7, characterized in that, The system for preparing propylene-ethylene-butyl terpolymer polypropylene also includes a first cyclone separator (6), a first filter (7), a compressor (8), a circulating pump (9), a condenser (10), and a second filter (11). The remaining propylene gas after the reaction in the polymerization reactor (5) is separated by the first cyclone separator (6), and the propylene-ethylene-butadiene ternary copolymer polypropylene powder is separated and sent back to the polymerization reactor (5). The separated propylene gas is filtered by the first filter (7) and condensed in the condenser (10). The propylene liquid obtained by condensation is sent back to the polymerization reactor (5) by the circulation pump (9), or the propylene liquid obtained by condensation is compressed by the delivery compressor (8) and then sent back to the polymerization reactor (5).

9. The method for producing ternary copolymer polypropylene from coal-to-olefins byproducts according to claim 7, characterized in that, The propylene gas recovered in the recovery unit is transported to the polymerization reactor (5) for recycling.

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