Method for preparing methanol based on carbon dioxide capture, method for preparing ethylene glycol and environment-friendly polyester

Abstract

The present disclosure relates to a method for preparing methanol based on carbon dioxide capture, a method for preparing ethylene glycol and an environment-friendly polyester. The method comprises the following steps: capturing and purifying a byproduct high-concentration carbon dioxide gas flow in a petroleum refining process into high-purity carbon dioxide, and then sequentially performing hydrogenation reaction in three-stage fixed bed reactors to prepare green methanol, wherein a copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst is used in the first-stage and third-stage reactors, and a copper-zirconium-titanium-vanadium deposition hydrogenation catalyst is used in the second-stage reactor. The green methanol can be prepared into ethylene glycol through an MTO process, ethylene oxidation and ethylene oxide hydrolysis. The ethylene glycol and terephthalic acid (PTA) can be prepared into the environment-friendly carbon-reducing polyester through slurry preparation, esterification reaction and polymerization reaction. In the esterification and polymerization processes, specific esterification catalysts and composite stabilizers are added to improve the performance.

Claims

1. A method for preparing methanol, the method using carbon dioxide and hydrogen as raw materials to prepare the methanol by hydrogenation reaction, wherein, the hydrogenation reaction being sequentially performed in three-stage fixed bed reactors, a copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst being filled in a first-stage fixed bed reactor, a copper-zirconium-titanium-vanadium deposition hydrogenation catalyst being filled in a second-stage fixed bed reactor, and the copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst being filled in a third-stage fixed bed reactor, the copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst being columnar and having a porous structure, comprising a supporting carrier and an active component, the active component comprising copper oxide, zinc oxide, calcium oxide, magnesium oxide and aluminum oxide, the copper-zirconium-titanium-vanadium deposition hydrogenation catalyst being columnar and having a porous structure, comprising a supporting carrier, a nano silicon dioxide carrier, and a porous deposition catalyst layer on the surface of the nano silicon dioxide carrier, the porous deposition catalyst layer comprising copper oxide, zirconium oxide, titanium oxide and vanadium oxide, and the supporting carrier comprising graphite, activated carbon and a binder; the copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst is prepared by a preparation method comprising the following steps: 1) mixing a water-soluble zinc salt solution, a water-soluble magnesium salt solution and a water-soluble aluminum salt solution to obtain a mixed solution; and adding an aqueous sodium hydroxide solution dropwise into the mixed solution to obtain a co-precipitation deposition suspension; 2) simultaneously adding an aqueous solution of water-soluble copper salt, an aqueous solution of water-soluble calcium salt and an aqueous sodium hydroxide solution dropwise into the co-precipitation deposition suspension; 3) adding an aqueous sodium bicarbonate solution to adjust the pH value of a reaction system; and aging by heating; 4) placing the reaction system in a high-pressure reaction kettle, and performing high-pressure blasting, dehydration treatment and re-dispersion into a suspension in water on the reaction system under the conditions of heating and stirring; 5) adding tetrabutyl silicate dropwise into the suspension; 6) filtering, adding graphite, activated carbon and a binder into a filter cake, and heating and shaping to obtain the copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst; the copper-zirconium-titanium-vanadium deposition hydrogenation catalyst is prepared by a preparation method comprising the following steps: 1) simultaneously adding an aqueous solution of a water-soluble copper salt, a tetraalkyl zirconium, a tetraalkyl titanate, an aqueous sodium metavanadate solution, an aqueous sodium hydroxide solution, and an aqueous sodium carbonate solution dropwise on the nano silicon dioxide carrier, so that the porous deposition catalyst layer is formed on the nano silicon dioxide carrier after reaction; the alkyl group is a C1-6 alkyl group; and 2) filtering, adding graphite, activated carbon, and a binder into a filter cake, and performing heat treatment to obtain the copper-zirconium-titanium-vanadium deposition hydrogenation catalyst.

2. The method for preparing methanol according to claim 1, wherein in the copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst, the supporting carrier accounts for 40%-50% and the active component accounts for 50%-60% by weight; and/or, in the copper-zirconium-titanium-vanadium deposition hydrogenation catalyst, the supporting carrier accounts for 40%-50%, the nano silicon dioxide carrier accounts for 20%-25%, and the porous deposition catalyst layer accounts for 25%-40% by weight.

3. The method for preparing methanol according to claim 2, wherein in the copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst, the copper oxide accounts for 30%-40% of the active component, the zinc oxide accounts for 23%-30% of the active component, the calcium oxide accounts for 4%-6% of the active component, the magnesium oxide accounts for 14%-18% of the active component, and the aluminum oxide accounts for 15%-20% of the active component by weight; and/or, in the copper-zirconium-titanium-vanadium deposition hydrogenation catalyst, the copper oxide accounts for 40%-50% of the porous deposition catalyst layer, the zirconium oxide accounts for 25%-35% of the porous deposition catalyst layer, the titanium oxide accounts for 10%-15% of the porous deposition catalyst layer, and the vanadium oxide accounts for 10%-15% of the porous deposition catalyst layer by weight.

4. The method for preparing methanol according to claim 1, wherein the specific surface area of the copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst is 125-150 m.sup.2/g; and/or, the length of the copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst is 4-8 mm; and/or, the specific surface area of the copper-zirconium-titanium-vanadium deposition hydrogenation catalyst is 80-100 m.sup.2/g; and/or, the length of the copper-zirconium-titanium-vanadium deposition hydrogenation catalyst is 4-8 mm.

5. The method for preparing methanol according to claim 1, wherein in the supporting carrier, the graphite accounts for 30%-35%, the activated carbon accounts for 45%-55%, and the binder accounts for 15%-20% by weight; and/or, the particle size of the graphite is 0.2-0.3 m; and/or, the activated carbon is coconut shell carbon micro powder.

6. The method for preparing methanol according to claim 1, wherein the first-stage fixed bed reactor comprises an inner chamber and an outer chamber, the inner chamber comprises a plurality of horizontal arranged trays, and two adjacent trays are staggered, the outer chamber is designed as a tower, and the top, middle and bottom of the outer chamber are all designed with a plurality of groups of homogenizing trays, the copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst is filled between the inner chamber and the homogenizing trays of the outer chamber, and a filter screen is arranged at the bottom of the outer chamber.

7. The method for preparing methanol according to claim 1, wherein the residence time of the raw gas in the first-stage fixed bed reactor is 135-160s; and/or, after the hydrogenation reaction of the first-stage fixed bed reactor is completed, the conversion rate of carbon dioxide is 38.0%-50%; and/or, the volume of the first-stage fixed bed reactor is 135-150 m.sup.3, and the volume of the filled copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst is 75-90 m.sup.3.

8. The method for preparing methanol according to claim 1, wherein the second-stage fixed bed reactor adopts a multi-layer tray reflux design, and the phase separation is completed during the reaction process, the bottom is a high-pressure methanol gas-liquid phase mixed product, and the top is an incompletely reacted mixed gas phase.

9. The method for preparing methanol according to claim 1, wherein the volume of the second-stage fixed bed reactor is 50-58 m.sup.3; and/or, the volume of the first-stage fixed bed reactor is 2.5-3.0 times that of the second-stage fixed bed reactor; and/or, the residence time of the reaction system in the second-stage fixed bed reactor is 35-45s.

10. The method for preparing methanol according to claim 1, wherein in the second-stage fixed bed reactor, the effective self-circulation ratio of the reaction system is 3.5-6.0; and/or, the cumulative conversion rate of carbon dioxide after the hydrogenation reaction of the second-stage fixed bed reactor is completed is 80.4%-91.5%.

11. The method for preparing methanol according to claim 1, wherein the third-stage fixed bed reactor comprises an inner chamber and an outer chamber, the inner chamber comprises a plurality of horizontal arranged trays, and two adjacent trays are staggered, the outer chamber is designed as a tower, and the top, middle and bottom of the outer chamber are all designed with a plurality of groups of homogenizing trays, the copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst is filled between the inner chamber and the homogenizing trays of the outer chamber, and a filter screen is arranged at the bottom of the outer chamber.

12. The method for preparing methanol according to claim 1, wherein the volume of the third-stage fixed bed reactor is 15-20 m.sup.3; and/or, the volume of the second-stage fixed bed reactor is 2.0-4.0 times that of the third-stage fixed bed reactor; and/or, the residence time of the reaction system in the third-stage fixed bed reactor is 60-90s; and/or, the cumulative conversion rate of carbon dioxide after the hydrogenation reaction of the third-stage fixed bed reactor is completed is 87.5%-95.0%.

13. The method for preparing methanol according to claim 1, wherein the carbon dioxide is derived from a byproduct of a petroleum refining process.

14. The method for preparing methanol according to claim 1, wherein the carbon dioxide and hydrogen are mixed and pressurized, and then fed into the first-stage fixed bed reactor from the bottom to perform the hydrogenation reaction, the reacted gas stream flows out of the bottom of the first-stage fixed bed reactor, enters a condenser to be condensed, and then enters a first methanol phase separation device after depressurization to perform phase separation.

15. The method for preparing methanol according to claim 14, wherein the gas stream at the top of the first methanol phase separation device is mixed with additional hydrogen to obtain a mixture, and the mixture is pressurized and fed into a middle and lower part of the second-stage fixed bed reactor to perform the hydrogenation reaction, and the reacted liquid component flows out of the bottom of the second-stage fixed bed reactor and enters the first methanol phase separation device to perform phase separation.

16. The method for preparing methanol according to claim 15, wherein the additional hydrogen accounts for 4%-8% of the volume of the hydrogen fed into the first-stage fixed bed reactor.

17. The method for preparing methanol according to claim 15, wherein an incompletely reacted gas is led out from the top of the second-stage fixed bed reactor, mixed with second additional hydrogen, and pressurized to enter a third-stage fixed bed reactor to perform the hydrogenation reaction, and a reacted gas stream flows out of the bottom of the third-stage fixed bed reactor and enters a second-stage methanol phase separation device to perform phase separation.

18. The method for preparing methanol according to claim 17, wherein the second additional hydrogen accounts for 0.3%-0.6% of the volume of the hydrogen fed into the first-stage fixed bed reactor.

19. A method for preparing ethylene glycol, comprising the steps of preparing ethylene from methanol by methanol-to-olefin technology, preparing ethylene oxide by oxidizing the ethylene, and preparing ethylene glycol by hydrolyzing the ethylene oxide, wherein the method further comprises the step of preparing methanol according to claim 1.

20. A method for preparing polyethylene terephthalate, comprising the steps of sequentially performing first esterification, second esterification, first prepolymerization, second prepolymerization, and final polymerization on terephthalic acid and ethylene glycol; wherein the method further comprises the steps of preparing the ethylene glycol according to claim 19, and adding an esterification catalyst and a composite stabilizer to the terephthalic acid and the ethylene glycol before performing the first esterification step; the esterification catalyst being selected from the group consisting of zinc acetate, manganese acetate, potassium acetate, sodium acetate, cobalt acetate, calcium acetate, and lithium acetate, or combinations thereof; the composite stabilizer comprises an amine stabilizer, sodium bisulfite, and a phosphorus stabilizer.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic diagram of a methanol synthesis device used in the embodiment;

(2) FIG. 2 is a schematic diagram of a first-stage fixed bed reactor used in the embodiment;

(3) FIG. 3 is a schematic diagram of a methanol distillation device used in the embodiment;

(4) Wherein, 1first-stage fixed bed reactor, 2second-stage fixed bed reactor, 3third stage fixed bed reactor, 4first methanol phase separation device, 5pressure swing adsorption (PSA) device, 6crude methanol storage tank, 7low pressure methanol distillation tower, 8methanol reflux tank, 9medium pressure methanol distillation tower, 10fine methanol storage tank, 11fusel oil storage tank, 12inner chamber, 13outer chamber, aCO.sub.2+H.sub.2, bH.sub.2, ctail gas, dcrude methanol, erefined methanol, ffusel oil.

DETAILED DESCRIPTION

(5) In the traditional synthesis of methanol by carbon dioxide hydrogenation reaction, for the high pressure and high temperature hydrogenation reactor, due to the limitation of material and reaction temperature (pressure resistance 15.0 Mpa, temperature resistance 350 C.), the structure volume of a single reactor can not be too large (generally according to the material balance, heat accounting and safety requirements, the full volume of 100,000 tons of methanol reactor is 50-100 m.sup.3), so that the gas flow has a short residence time in the reactor. The existing methanol reactor design (the full volume of 100,000 tons of methanol reactor is about 50 m.sup.3) adopts a large-flux self-circulation design of tail gas, which has high energy consumption, short residence time of mixed gas flow in the catalyst area, low single-pass reaction degree, and very low overall conversion rate of carbon dioxide.

(6) The three-stage methanol reactors of the present disclosure adopt a reinforced design, wherein the first-stage methanol reactor adopts a single circulation reaction, and the residence time of the initial mixed gas in the first-stage reactor is extended by 3.0-5.5 times, and the sufficient residence time effectively improves the reaction conversion rate.

(7) One of the aspects of the present disclosure is that a hydrolysis-resistant copper-zirconium-titanium-vanadium deposited hydrogenation catalyst is used in the second-stage methanol reactor, which has the effects of resisting hydrolysis and inactivation. The catalyst is developed and designed according to the characteristics of the reaction gas phase components separated by the methanol phase separation device after the reaction of the first-stage hydrogenation reactor is completed. By using the catalyst, the hydrogenation reaction can be completed at a lower temperature and a higher pressure, and the mixed phase is separated by gas-liquid separation, and then the crude methanol and high-boiling by-products are introduced into the crude methanol storage tank from the bottom of the reactor, and the gas phase part is guided out from the top of the reactor and sent into the third stage methanol reactor. In the second-stage reactor, by using the aforementioned hydrolysis-resistant hydrogenation catalyst, the carbon dioxide and hydrogen which are not reacted in the first-stage methanol reactor can further reacts so that the hydrogenation reaction degree of carbon dioxide is further improved.

(8) The third stage hydrogenation reactor is an auxiliary system for further improving the carbon dioxide conversion rate on the basis of the main reaction completed by the first and second-stage reactors. Because the by-product content in the tail gas from the top of the second-stage methanol reactor is further increased, the catalyst used in the third stage reactor is the same as that in the first-stage.

(9) Another of the aspects of the present disclosure is in the first-stage methanol reactor of the main reaction device, the raw material from a inlet is pure carbon dioxide and hydrogen mixed gas. Compared with the single stage designed methanol reactor, the unreacted recycled gas is injected into the mixed gas inlet in the present disclosure, and then the influence of the reaction by-products especially the water in the by-products on the catalyst activity is eliminated, the life of the hydrogenation catalyst is greatly prolonged, and the efficiency of the main reaction of the first-stage methanol reactor is improved. Another advantage of the three-stage methanol reactor is that the staged reaction effectively prolongs the residence time of the mixed gas flow in the main reaction zone, and effectively improves the conversion rate of a single cycle reaction. The present disclosure introduces the unreacted mixed gas at the top of the methanol phase separation device which is shared by the first-stage and the second-stage methanol reactors into the second-stage methanol reactor after being pressurized by a compressor, and adopts a large proportion of cycle reaction mode.

(10) One of the aspects of the present disclosure is the specific structural setting of the first-stage fixed bed reactor, specifically, the carbon dioxide gas and hydrogen are mixed after being compressed and injected into the system from the bottom of the inner chamber of the first-stage fixed bed reactor. The inner chamber of the reactor is designed as a multilayer tray design, for each stage of tray, the reaction mixed gas enters from a corner of the bottom of the tray, flows horizontally along the tray, and then enters the upper channel of the diagonal bottom corner into the upper tray, and so on to the top of the inner chamber. The design effectively prolongs the contact residence time of the mixed gas and the catalyst, and improves the reaction uniformity and reaction efficiency. The outer chamber is designed as a tower design, the mixed gas is collected to the top of the reactor after reacting in the inner chamber, and then enters the outer chamber to react, and the mixed gas flow in the outer chamber flows from the top to the bottom of the reactor and is collected, cooled by heat exchange, and introduced into the first methanol phase separation device. The top, middle and bottom of the outer chamber are all designed with multiple groups of homogenizing discs between which are filled with the catalyst particles. Each homogenizing disc first collects the gas, and then guides the gas to the next layer through the homogenizing design channel, so that the mixed gas flow uniformly passes through multiple catalyst layers in the tower body, and a filter screen is designed at the bottom of the outer chamber to prevent the catalyst particles from entering the bottom outlet.

(11) The second-stage methanol reactor has a device capacity of a mixed gas phase flow flux of 50,000-150,000 tons and an effective full volume of 50%-65% of the first-stage methanol reactor, and adopts a multilayer tray reflux design, and completes phase separation during the reaction process, so that the bottom is a high-pressure methanol gas-liquid phase mixed product, and the top is an unreacted mixed gas phase product.

(12) The third stage methanol reactor adopts the same design as the first-stage methanol reactor, and has a device capacity of a mixed gas phase flow flux of 4,000-8,000 tons. The bottom of it discharges the mixed gas after reaction which then can be sent to a separately designed second methanol phase separation device, and the liquid phase is transported to a crude methanol storage tank after being separated by decompression, while the gas phase is guided to a pressure swing adsorption (PSA) device, and then the unreacted hydrogen is recovered, and then sent to a waste gas treatment system for harmless treatment and emptying.

(13) Different from ethylene glycol EG prepared by a petrochemical ethylene process, the green ethylene glycol prepared by the present disclosure has different impurity by-products in the composition, especially in the variety and content of low-molecular aldehydes and organic acids. In detail, the ethylene glycol prepared by the present disclosure has higher acetaldehyde content, lower 1,4-dioxane content, slightly higher low-molecular carboxylic acid content, and slightly lower ultraviolet light transmittance at 220 nm and 250 nm than the petrochemical ethylene glycol. This can lead to a decrease in the hue L value, a lower a value and a higher b value of the PET product. The esterification reaction rate of the green ethylene glycol is obviously lower than that of the petrochemical ethylene glycol, and under the same esterification conditions, the esterification conversion rate of the green ethylene glycol in the first esterification step is decreased by 3%-5%, and the esterification conversion rate of the green ethylene glycol in the second esterification step is decreased by 2.2%-4.0%.

(14) One more of the aspects of the present disclosure is to add an esterification catalyst to ensure that the esterification reaction proceeds smoothly, the manganese element in the manganese acetate of the esterification catalyst has reducibility, and can react with a metal compound with oxidizability in the reaction process, and can also react with an oxidant component in the reaction system, thereby avoiding the deactivation of the effective active center components of antimony and titanium catalysts, and ensuring a good esterification reaction state of the green ethylene glycol. In addition, during polymerization, an alcohol amine stabilizer with complexing function is combined with sodium bisulfite to form a composite stabilizer with a phosphorus stabilizer. The alcohol amine stabilizer can effectively complex and block heavy metal ions and reducible low-molecular organic impurities in the green ethylene glycol, and the sodium bisulfite can block the by-products with active aldehyde and ketone groups, thereby reducing the side reaction level of the components, and the phosphorus stabilizer can control the thermal degradation reaction in the esterification and polymerization reaction processes.

(15) The carbon dioxide hydrogenation technology of the present disclosure has following advantages, 1) the full volume of the first-stage methanol reactor is effectively increased, and the residence time of a carbon dioxide and hydrogen mixed gas in the methanol reactor fixed bed is greatly increased, 2) a unique inner chamber gas phase flow channel design and outer chamber homogenization design are adopted, the reaction is more uniform, 3) the first-stage methanol reactor does not adopt tail gas circulation, and the one-stage reaction conversion rate is increased, 4) a high-proportion self-circulation technology of the second-stage methanol reactor is adopted, and the process flow is further optimized, 5) a third-stage methanol synthesis reactor is combined, a more reasonable process flow technology is adopted, the catalyst service cycle is prolonged, the conversion efficiency of the carbon dioxide hydrogenation methanol preparation is increased, and the device operation stability is further increased from the material reaction level by adopting catalysts with different components.

(16) The present disclosure is further explained in detail below in combination with specific embodiments; it should be understood that, those embodiments are to explain the basic principle, major features and advantages of the present disclosure, and the present disclosure is not limited by the scope of the following embodiments; the implementation conditions employed by the embodiments may be further adjusted according to particular requirements, and undefined implementation conditions usually are conditions in conventional experiments. In the following embodiments, unless otherwise specified, all raw materials are basically commercially available or prepared by conventional methods in the field.

(17) The embodiments described below are only for illustrating the technical concepts and features of the present disclosure, and are intended to make a person familiar with the technology being able to understand the content of the present disclosure and thereby implement it, and should not limit the protective scope of this disclosure. Any equivalent variations or modifications according to the spirit of the present disclosure should be covered by the protective scope of the present disclosure.

(18) The present application is further described below in combination with the drawings and the preferred embodiments of the present application. The orientation and position relationship described in the present application are only for the convenience of description and simplifying the description, and are not used to indicate or imply that the device or element referred to must have a specific orientation, only have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

(19) As shown in FIGS. 1-3, the device system for preparing methanol comprises three-stage fixed bed reactors for synthesizing methanol in FIG. 1, and a device for distilling methanol in FIG. 2. The first-stage fixed bed reactor 1 is filled with a copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst, the second-stage fixed bed reactor 2 is filled with a copper-zirconium-titanium-vanadium deposition hydrogenation catalyst, and the third-stage fixed bed reactor 3 is filled with a copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst.

(20) As shown in FIG. 2, the first-stage fixed bed reactor 1 comprises an inner chamber 12 and an outer chamber 13. The inner chamber 12 comprises multiple layers of horizontally arranged trays (not shown, and the flowing path of the gas flow is shown, and the flowing path of the gas flow is diagonal due to the staggered design of the trays) and two adjacent trays are staggered. The outer chamber 13 is designed in a tower type, and multiple groups of homogenizing trays (not shown, and the flowing path of the gas flow is shown, and the flowing path of the gas flow is diagonal due to the staggered design of the trays) are arranged at the top, middle and bottom of the outer chamber 13. The copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst is filled between the homogenizing trays of the inner chamber 12 and the outer chamber 13. A filter screen (not shown in the figure) is arranged at the bottom of the outer chamber 13.

(21) The second-stage fixed bed reactor 2 adopts a multi-layer tray 14 reflux design, and the phase separation is completed during the reaction process. The bottom is a high-pressure methanol gas-liquid phase mixed product, and the top is an unreacted mixed gas phase.

(22) The third-stage fixed bed reactor 3 adopts the same structure as the first-stage fixed bed reactor 1.

(23) As shown in FIG. 1, carbon dioxide and hydrogen are mixed and pressurized, and then fed from the bottom into the first-stage fixed bed reactor 1 for hydrogenation reaction. The gas stream after reaction flows out from the bottom of the first-stage fixed bed reactor 1, enters a condenser for condensation, and then enters the first methanol phase separation device 4 for phase separation after depressurization. The gas stream at the top of the first methanol phase separation device 4 is mixed with additional hydrogen, and then pressurized and fed from the middle and lower part into the second-stage fixed bed reactor 2. The mixed gas stream is subjected to hydrogenation reaction in the second-stage fixed bed reactor 2. The liquid components after reaction flow out from the bottom of the second-stage fixed bed reactor 2, and enter the first methanol phase separation device 4 for phase separation. The incompletely reacted gas is led out from the top of the second-stage fixed bed reactor 2, mixed with the second additional hydrogen, and then pressurized and fed into the third stage fixed bed reactor 3 for hydrogenation reaction. The gas stream after reaction flows out from the bottom of the third stage fixed bed reactor 3, and enters the second methanol phase separation device for phase separation. The tail gas at the top of the third stage fixed bed reactor 3 is subjected to depressurization treatment, and then led into the pressure swing adsorption (PSA) device 5 for hydrogen adsorption, desorption and recovery. The recovered hydrogen is used as the additional hydrogen fed into the second-stage fixed bed reactor 2 and the second additional hydrogen fed into the third stage fixed bed reactor 3. The liquefied crude methanol obtained from the first and second methanol phase separation devices in the three stage fixed bed reactors can be stored in the crude methanol storage tank 6.

(24) As shown in FIG. 3, the liquid crude methanol obtained from the first methanol phase separation device 4 and the second methanol phase separation device is subjected to two-stage distillation separation. The pressure of the second-stage distillation is higher than that of the first-stage distillation. For the two-stage distillation separation system, the first-stage distillation adopts low pressure distillation. The crude methanol is fed into the bottom of the low pressure methanol rectification tower 7. The methanol is taken out from the top of the distillation tower, cooled and returned to the refined methanol storage tank 10. The heavy components at the bottom of the low pressure methanol distillation tower 7 mainly include 50%-60% methanol and other high boiling point by-products, which are fed into the middle of the medium pressure methanol distillation tower 9 by a circulating pump, and then high quality methanol is further taken out from the top of the tower by distillation, cooled and returned to the refined methanol storage tank 10. The high boiling point components taken out from the bottom are fed into the fusel oil storage tank 11 as fusel oil for further treatment.

Preparation Example 1

(25) The present preparation example provides a copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst, and a preparation method thereof is specifically as follows:

(26) First, 1.0M of aqueous solutions of a copper sulfate, zinc sulfate, calcium chloride, magnesium sulfate, aluminum sulfate are prepared respectively and filtered for use. 1.0M sodium hydroxide solution, 0.5M sodium bicarbonate solution is also prepared. A zinc sulfate solution, magnesium sulfate solution, aluminum sulfate solution is mixed in a molar ratio of 1.0:1.0:0.75 to obtain a mixed solution, and the sodium hydroxide solution is added dropwise into the mixed solution under stirring in 4.0 hours, with the molar ratio of metal ions and hydroxide in accordance with the stoichiometric ratio, and a co-precipitation deposition suspension is obtained. The temperature of the reaction system is controlled at 70 C., and after the drop addition is completed, the reaction is continued for 2.0 hours.

(27) A copper sulfate solution, calcium chloride solution in a molar ratio of 1.5:1.8 and the sodium hydroxide solution are added dropwise to the co-precipitation deposition suspension simultaneously and the total valence of the two metal ions was equal to the total valence of hydroxide ions, and the dropwise addition time is controlled for 4 hours, and the pH value of the system is controlled at about 10 during the dropwise addition. After the completion of the dropwise addition, the pH value of the suspension is adjusted to 10.0 with the sodium bicarbonate solution. The suspension is heated to 90 C. and stabilized for 1.0 hour. Then the suspension is transferred to a 2.5 MPa pressure-resistant stainless steel reactor, heated to 220 C. under high-speed stirring conditions and stirred for 5.0 hours, and then a high-pressure circulating pump is started, and the suspension is transported to a specially designed high-pressure blasting nozzle. The suspension is first dehydrated under high-pressure overheating conditions in the high-pressure blasting nozzle, and then suddenly blasted to normal pressure conditions, and in the process, the submicron powder in the suspension is blasted into nano powder, and the porosity and specific surface area of the powder are greatly improved.

(28) The nano powder after blasting is partially dehydrated, the soluble components are washed away with distilled water, and then a water suspension with a concentration of 10% is formed under stirring. Tetrabutyl silicate accounting for 150 ppm of the powder mass is added dropwise to the water suspension at 80 C., and the dropwise addition time is controlled for 6 hours, after the completion of the dropwise addition, aging is performed for 2.0 hours. The water is removed by filtration, and submicron graphite, coconut shell carbon micro powder and a binder (the mass ratio of the three is 3:5:2) are added to the filter cake as a supporting carrier to prepare columnar porous pellets, which are dried and shaped at 320 C. to obtain a copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst.

(29) The specific surface area of the catalyst is 125 m.sup.2/g, and the catalyst is columnar with a length of 4.0 mm.

(30) In the catalyst, the supporting carrier accounts for 40 wt %, and the active component accounts for 60 wt %. In the active component, a copper oxide accounts for 35.0 wt %, a zinc oxide accounts for 26.0 wt %, a calcium oxide accounts for 4.2 wt %, a magnesium oxide accounts for 16.8 wt %, and a aluminum oxide accounts for 18.0 wt %.

Preparation Example 2

(31) The present preparation example provides a copper-zirconium-titanium-vanadium deposition hydrogenation catalyst, and a preparation method thereof is specifically as follows:

(32) A prepared copper sulfate aqueous solution (concentration: 3.0 mol/L), tetraethyl zirconium, tetraisopropyl titanate, sodium metavanadate aqueous solution (concentration: 2.0 mol/L), sodium hydroxide aqueous solution (concentration: 2.5 mol/L), and sodium carbonate aqueous solution (concentration: 2.0 mol/L) are synchronously added dropwise into a nano-silica which used as a carrier. The pH value of the system is strictly controlled to be 10 during the dropwise addition. The precipitates formed by the reaction of the four metal ions with the alkali liquor are deposited on the surface of the nano-silica carrier to form a porous deposition catalyst layer. Then, the suspension is filtered and washed, and is mixed with submicron graphite, coconut shell carbon micro powder and a binder (mass ratio: 3:5:2, as a supporting carrier) to be compressed into columnar porous catalyst particles. The columnar porous catalyst particles are sent into a muffle furnace for treatment at 600 C. for 16 hours to obtain a copper-zirconium-titanium-vanadium deposition hydrogenation catalyst. The surface of the catalyst is porous.

(33) The specific surface area of the catalyst is 100 m.sup.2/g, and the catalyst is columnar with a length of 5.0 mm.

(34) In the catalyst, the supporting carrier accounts for 40 wt %, the nano-silica carrier accounts for 20 wt %, and the active component porous deposition catalyst layer accounts for 40 wt %. In the active component, the copper oxide accounts for 45 wt %, the zirconium oxide accounts for 30 wt %, the titanium oxide accounts for 12.0 wt %, and the vanadium oxide accounts for 13.0 wt %.

Comparative Preparation Example 1

(35) A hydrogenation catalyst is prepared by the method as in Preparation Example 1, by only differing in that: the raw materials don't comprise calcium chloride aqueous solution.

Comparative Preparation Example 2

(36) A hydrogenation catalyst is prepared by the method as in Preparation Example 1, by only differing in that: the raw materials don't comprise the magnesium sulfate aqueous solution.

Comparative Preparation Example 3

(37) A deposition hydrogenation catalyst is prepared by the method as in Preparation Example 2, by only differing in that: the raw materials don't comprise the tetraethyl zirconium.

Comparative Preparation Example 4

(38) A deposition hydrogenation catalyst is prepared by the method as in Preparation Example 2, by only differing in that: the raw materials does not comprise the sodium metavanadate aqueous solution.

Example 1

(39) This example provides a preparation method of methanol, and the method is specifically as follows.

(40) Taking a 200,000 t/year methanol device prepared by hydrogenation of carbon dioxide as an example, the sources and quality indexes of raw hydrogen and carbon dioxide are as follows:

(41) Hydrogen: when propylene is prepared by a methanol-to-olefin technology (MTO process) with green power as energy, the byproduct is hydrogen. The quality indexes (hydrogen content and impurity content) and process parameter are as shown in Table 1 below:

(42) TABLE-US-00001 TABLE 1 hydrogen raw material indexes and process parameters Gas component, process Component content parameter (volume), process parameter H.sub.2 99.99% (VOL) O.sub.2 5 ppm CO 1 ppm CO.sub.2 10 ppm H.sub.2O 50 ppm CH.sub.4 50 ppm C.sub.2H.sub.4 10 ppm C.sub.3H.sub.6 10 ppm H.sub.2S 1 ppm N.sub.2 100 ppm Temperature 42 C. Pressure 2.4 MPa Flow rate 55088 Nm.sup.3/h (Nm.sup.3/hour)

(43) Carbon dioxide: The high concentration carbon dioxide gas stream (mass index shown in Table 2 below) generated in petroleum refining is recovered. The carbon dioxide waste gas is first captured, compressed, enriched (by pressure swing adsorption PSA device), desulfurized and denitrified to prepare carbon dioxide raw gas with a volume content of more than 98.0%;

(44) TABLE-US-00002 TABLE 2 carbon dioxide raw material index and process parameters Gas component, process Component content parameter (volume), process parameter CO.sub.2 80.0-92% vol H.sub.2 0.16% vol H.sub.2O Saturated N.sub.2 15.0-19.98% vol CO 0.01% vol Temperature 40 C. Pressure 0.5 MPa Flow rate 18866 Nm.sup.3/h (Nm.sup.3/hour)

(45) The purified carbon dioxide gas is mixed with hydrogen, and then pressurized to 10.0 MPa and heated to 265 C. The mixed gas is delivered to the inner chamber of the first-stage methanol reactor (first-stage fixed bed reactor), flows through the catalyst fixed bed in the inner chamber, and then reaches the top of the methanol reactor. The mixed gas flows uniformly from top to bottom through the outer chamber homogenizer at the top, the outer chamber multilayer catalyst fixed bed and the gas homogenizer to complete the first-stage circulating process catalytic hydrogenation reaction. The mixed gas is delivered from the bottom of the outer chamber to the first methanol phase separation device through heat exchange and pressure reduction equipment. The catalysts filled in the inner chamber and the outer chamber are the catalysts of Preparation Example 1. In the first-stage methanol reactor, the total residence time of the carbon dioxide and hydrogen mixed phase is 145 seconds. The results are that the carbon dioxide conversion rate is 40.25% and the reaction selectivity is 97.0%.

(46) The first methanol phase separation device is further cooled and refluxed, and heavy components such as crude methanol and reaction generated water are collected from the bottom and then delivered to a crude methanol intermediate tank.

(47) The mixed gas that is not reacted at the top of the first methanol phase separation device is pressurized and heated (the temperature is raised to 180 C. and the pressure is raised to 15.0 MPa) by a compressor and a heat exchanger, and then delivered to the second-stage methanol reactor (second-stage fixed bed reactor). The second-stage methanol reactor adopts a design structure different from that of the first-stage reactor, and the gas-liquid phase unreacted mixed gas, crude methanol, water and high boiling point by-products are led out from the bottom and delivered to the first methanol phase separation device for separation.

(48) The mixed gas at the top of the first methanol phase separation device which is from the first and second methanol reactors is recycled to the second methanol reactor via a compressor. The unreacted gas phase component is taken out from the top of the first and second methanol reactors and directly sent to the third methanol reactor (third fixed bed reactor) via a compressor.

(49) The second methanol reactor adopts a large-flux self-circulation mode to improve the reaction efficiency. The reactor is filled with the catalyst of Preparation Example 2. The residence time of the mixed phase in the second methanol reactor is 35 seconds, and the effective self-circulation ratio is 3.5 times. After the second methanol reactor, the cumulative conversion rate of carbon dioxide is 85.0%.

(50) The mixed gas taken out from the top of the second methanol reactor is compressed and fed into the third methanol reactor. The third methanol reactor adopts the same structure as the first methanol reactor and the same catalyst of Preparation Example 1. After the catalytic hydrogenation reaction in the third methanol reactor, the mixed gas is introduced into a separately designed second methanol phase separation device for separation. The liquid phase crude methanol at the bottom of the separator is fed into a crude methanol storage tank, and the tail gas at the top is introduced into a PSA hydrogen recovery device after decompression. The recovered hydrogen is desorbed and mixed into the carbon dioxide pipeline of the second methanol reactor. The tail gas after hydrogen adsorption contains a small amount of carbon dioxide, methane, ethane, formaldehyde, acetaldehyde and trace hydrogen, and is sent to a tail gas incineration device for treatment and venting. The liquefied crude methanol generated in the third methanol reactor is fed into the crude methanol storage tank. In the third methanol reactor, the residence time of the mixed phase is 60 seconds, and the cumulative conversion rate of carbon dioxide is 94.9% after the third methanol reactor.

(51) The crude methanol taken out from the first, second and third methanol reactors is collected into a crude methanol storage tank and then sent to a two-stage distillation system. A refined methanol is taken out from the top of a first-stage low-pressure methanol distillation tower, and methanol, water and high-boiling by-products are taken out from the bottom. The components are heated and gasified and sent to a second-stage medium-pressure distillation tower. After the two-stage distillation tower, refined methanol is taken out from the top, and heavy components at the bottom are refluxed to separate water which is then sent to a water treatment device for treatment. The remaining fusel oil after water removal is sent to a fusel oil storage tank for storage and treatment. The tail gas is collected into a tail gas treatment device, treated and vented. The refined methanol products distilled from the two-stage distillation towers are collected into a refined methanol storage tank. The indexes of refined methanol product are shown in Table 3.

(52) TABLE-US-00003 TABLE 3 Methanol product indexes (GB 338-2011) Item GB 338-2011 (superior) Appearance Colorless and transparent, no visible impurities Methanol content 99.85% w/w Acetone Acid (calculated as HCOOH) 0.0015% w/w Carbonizable substances 50 (sulfuric acid washing test, platinum- cobalt color number) Chroma 55 Boiling range 760 mm 0.8 C. Evaporation residue 0.001% w/w Odor No abnormal odor Potassium permanganate test 50 min Specific gravity at 20 C. 0.791-0.792 g/cm Moisture 0.10% w/w Hydroxy compounds (as HCHO) 0.002% w/w

(53) For the 200,000 t/year carbon dioxide hydrogenation to prepare methanol project of the present embodiment, the carbon dioxide conversion rate was 94.9%, and the device material balance data are as shown in Table 4.

(54) TABLE-US-00004 TABLE 4 Project process device material balance table Project name Material name Unit Value Feed H.sub.2 feed gas Kg/h 4974 CO.sub.2 feed gas Kg/h 36864 Output product Refined methanol Kg/h 24928 By-product water Kg/h 14204 Tail gas Kg/h 2414 Fusel oil Kg/h 290

Comparative Example 1

(55) The present comparative example provides a method for preparing methanol, which is basically the same as that of Example 1, by only differing in that: the catalysts in the first-stage fixed bed reactor and the third-stage fixed bed reactor are replaced with the catalyst of Comparative Preparation Example 1. As a result, the cumulative conversion rate of carbon dioxide is 91.8%.

Comparative Example 2

(56) The present comparative example provides a method for preparing methanol, which is basically the same as that of Example 1, by only differing in that: the catalysts in the first-stage fixed bed reactor and the third-stage fixed bed reactor are replaced with the catalyst of Comparative Preparation Example 2. As a result, the cumulative conversion rate of carbon dioxide is 92.2%.

Comparative Example 3

(57) The present comparative example provides a method for preparing methanol, which is basically the same as that of Example 1, by only differing in that: the catalyst in the second-stage fixed bed reactor is replaced with the catalyst of Comparative Preparation Example 3. As a result, the cumulative conversion rate of carbon dioxide is 90.6%.

Comparative Example 4

(58) The present comparative example provides a method for preparing methanol, which is basically the same as that of Example 1, by only differing in that: the catalyst in the second-stage fixed bed reactor is replaced with the catalyst of Comparative Preparation Example 4. As a result, the cumulative conversion rate of carbon dioxide is 88.7%.

Example 2

(59) The present example provides a method for preparing green ethylene glycol, which is specifically as follows:

(60) The green refined methanol prepared in Example 1 is transported to an MTO device for preparing olefins from methanol, in which the green refined methanol is first used to prepare ethylene, and then the ethylene is used to prepare green ethylene oxide by oxidation, and the green ethylene oxide is hydrolyzed to prepare green ethylene glycol. The process for preparing green ethylene glycol from green methanol has been widely applied in the methanol chemical industry, and the present example adopts a conventional chemical industry implementation mode. The indexes of the finally obtained green ethylene glycol are shown in Table 5.

(61) The obtained green ethylene glycol meets the requirements of GB/T4649-2018 and conforms to the quality requirements of polyester-grade ethylene glycol raw materials, but compared with petrochemical ethylene glycol, the tested ultraviolet transmittance at 220 nm and 250 nm of it is lower than that of petrochemical ethylene glycol, although it meets the national standard quality requirements. The reason is that the content of low-molecular aldehydes, carboxylic acids and low-molecular carboxylic acid esters, and alcohol by-products in the green ethylene glycol is higher than that in the petrochemical ethylene glycol.

(62) TABLE-US-00005 TABLE 5 performance indicators of green ethylene glycol Standard requirement of polyester-grade ethylene Performance of EG of No Item glycol Example 2 Note: 1 Appearance Transparent liquid, no Transparent liquid, no mechanical impurities mechanical impurities 2 Ethylene glycol, w % 99.9 99.92 3 Diethylene glycol, w % 0.050 0.021 4 1,4-Butanediol , w % Reported .sup.b 0.005 Reported .sup.b 5 1,2-Butanediol , w % Reported .sup.b 0.002 Reported .sup.b 6 1,2-Hexanediol , w % Reported .sup.b Not detected Reported .sup.b 7 Ethylene carbonate , Reported .sup.b 0.001 Reported .sup.b w % 8 Chromaticity (platinum- 5 1.0 cobalt)/number Before 20 6.7 heating After heating with hydrochloric acid 9 Density (20 C.) 1.1128~1.1138 1.1133 (g/cm.sup.3) 10 Boiling range (at 0 C., 196.0 196.5 101.33 Kpa) 199.0 198.6 Initial boiling point/ C. Dry point/ C. 11 Moisture, w % 0.08 0.05 12 Acidity (calculated as 10 4.0 acetic acid)/(mg/kg) 13 Iron content/(mg/kg) 0.10 0.02 14 Ash/(mg/kg) 10 1.0 15 Aldehyde 8.0 6.8 content(calculated as formaldehyde)/(mg/kg) 16 Ultraviolet 75 77.2 Compared with transmittance/% Reported .sup.b Reported .sup.b the ethylene glycol 220 nm 92 93.5 obtained by the 99 99.7 petrochemical method, 250 nm the measured values of 275 nm 220 nm and 250 nm are slightly low 350 nm 17 Chloride ion/(mg/kg) 0.5 0.01 .sup.a The petrochemical method and the ethylene oxidation/ethylene oxide hydration process do not require the item, but the green method requires the item .sup.b Reported means that the data need to be measured and provided, and items 4-7 in the above table are given according to a report

Example 3

(63) The present example provides a preparation method for green polyethylene terephthalate (PET), which is specifically as follows.

(64) The green ethylene glycol prepared in the above example 2 is used as a raw material of polyester, and polymerization and spinning is performed on a 50,000 t/year continuous polymerization melt direct spinning device.

(65) Device capacity: 150 t/d, using ultra-low temperature five-kettle process design, and by melt direct spinning.

(66) A refined terephthalic acid (PTA) and the green ethylene glycol (EG) are configured into slurry in a molar ratio of 1:1.135, and a prepared esterification catalyst, namely, a mixture of zinc acetate, manganese acetate and lithium acetate (molar ratio of 1:0.3:0.5) is injected into a slurry tank, and the total addition amount of the esterification catalyst is controlled to be 100 ppm of polyester product PET. A composite stabilizer is injected into the slurry through a designed injection port in a slurry conveying pipeline, and the composite stabilizer is consisted of triethanolamine, sodium bisulfite and triphenyl phosphite, wherein the amount of the triethanolamine accounts for 50 ppm of the mass of PET, the amount of the sodium bisulfite accounts for 20 ppm of the mass of PET, and the amount of the triphenyl phosphite accounts for 150 ppm of the mass of PET.

(67) After the slurry is uniformly mixed, the slurry is conveyed to a first esterification reactor for a preliminary esterification reaction, and the temperature of the first esterification reactor is controlled to be 256-258 C., the pressure is controlled to be 75 KPa, and the esterification rate of the first esterification reactor is controlled to be 90%-91.5%.

(68) The melt after the reaction in the first esterification reactor is introduced into the second esterification reactor. The second esterification reactor is a multi-chamber design and is divided into three esterification reaction chambers. The reaction temperature at the outlet of the second esterification reactor is 260-262 C. A prepared nano-barium sulfate tracer (a suspension of barium sulfate in ethylene glycol, the mass concentration is 5%, and the particle size of the barium sulfate is 50 nm) is added into the first chamber of the second esterification reactor. The amount of the nano-barium sulfate tracer is 50 ppm of the mass of PET, and the nano-barium sulfate tracer is used as a marker to track the whole life cycle of the green carbon-reduced polyester. A titanium-based multi-metal catalyst (the catalyst in Example 1 of CN117567730A) is added into the second chamber of the second esterification reactor. The concentration of titanium element is 8 ppm of the mass of PET. A liquid matting agent is added into the third chamber of the second esterification reactor. The mass of the liquid matting agent is 0.3% of the mass of PET.

(69) The melt after the second esterification reaction in the second esterification reactor is introduced into a first prepolymerization reactor. The esterification rate of the melt is 96.5%-97.8%. The reaction temperature in the first prepolymerization reactor is controlled to be 269-271 C. The vacuum degree is 10.0-12.0 KPa. The melt after a first prepolymerization reaction in the first prepolymerization reactor is introduced into a second prepolymerization reactor to further complete the prepolymerization reaction. The second prepolymerization reactor is a single-shaft disc reactor. The reaction temperature is controlled to be 273-275 C. The vacuum degree is 1.0-1.3 KPa. The intrinsic viscosity of the prepolymer is controlled to be 0.240-0.285 (measured in a mixed solvent of phenol:tetrachloroethane=3:2 (V/V)). The melt after the prepolymerization reaction is conveyed to the final polymerization reactor through a prepolymer conveying pump and a prepolymer filter. The final polymerization reactor is a front-rear double-shaft disc reactor. The reaction temperature at the outlet of the final polymerization reactor is controlled to be 280-282 C. The vacuum degree is 150-175 Pa. The intrinsic viscosity at the outlet is controlled to be 0.640-0.645 (measured in a mixed solvent of phenol:tetrachloroethane=3:2 (V/V)). The melt is conveyed to a direct spinning workshop through a melt conveying pump. Various green carbon-reduced polyester fibers with different specifications are spun. The process parameters are shown in Table 6.

Example 4

(70) The present example provides a method for preparing green polyethylene terephthalate PET, which is basically the same as that of Example 3, by only differing in that: the process parameters are slightly different and as shown in Table 6 below, and the dosage of the tracer barium sulfate added into the first chamber of the second esterification reactor is increased to 100 ppm.

Example 5

(71) The present example provides a method for preparing green polyethylene terephthalate PET, which is basically the same as that of Example 3, by only differing in that: the process parameters are slightly different and as shown in Table 6 below, and 60 ppm (based on mass of PET) of 2,2,4,4-cyclohexanedicarboxylic acid is added into the pulping reactor and 50 ppm (based on mass of PET) of nano-barium sulfate is also added into the second esterification reactor.

Example 6

(72) The present example provides a method for preparing green polyethylene terephthalate PET, which is basically the same as that of Example 3, by only differing in that: the process parameters are slightly different and as shown in Table 6 below, and 80 ppm (based on mass of PET) of 2,2,4,4-cyclohexanedicarboxylic acid is added into the pulping reactor and 80 ppm (based on mass of PET) of nano-barium sulfate is added into the second esterification reactor.

Example 7

(73) The present example provides a method for preparing green polyethylene terephthalate PET, which is basically the same as that of Example 3, by only differing in that: the process parameters are slightly different and as shown in Table 6 below, and 75 ppm (based on mass of PET) of 2,2,4,4-cyclohexanedicarboxylic acid is added into the pulping reactor and 100 ppm (based on mass of PET) of sub-nanometer calcium carbonate-magnesium carbonate composite (calcium: 40 ppm, magnesium: 60 ppm) is added into the second esterification reactor.

Example 8

(74) The present example provides a method for preparing green polyethylene terephthalate PET, which is basically the same as that of Example 3, by only differing in that: the process parameters are slightly different and as shown in Table 6 below, and 75 ppm (based on mass of PET) of pentaerythritol is added into the pulping reactor and 100 ppm (based on mass of PET) of sub-nanometer calcium carbonate-magnesium carbonate composite (calcium: 40 ppm, magnesium: 60 ppm) is added into the second esterification reactor.

(75) TABLE-US-00006 TABLE 6 Process parameters First Second esterification esterification First Second Final First acid Second acid prepolymer- prepolymer- polymer- Outlet esterification value/mg esterification value/ ization ization Prepolymer ization intrinsic No. ( C./kpa) KOH/t ( C.) mgKOH/t ( C./kpa) ( C./kpa) viscosity ( C./pa) viscosity Example 3 256.5/75.0 65.7 262.6 27.9 270.2/10.7 273.8/1.04 0.269 281.2/155.2 0.642 Example 4 256.2/75.0 68.9 262.2 28.5 270.5/10.2 273.5/1.00 0.262 281.5/157.0 0.640 Example 5 256.0/75.0 68.6 262.5 28.2 270.8/10.4 273.7/1.06 0.265 281.5/150.7 0.645 Example 6 256.8/75.0 64.3 262.4 27.7 271.0/10.5 274.2/1.10 0.272 280.8/152.5 0.641 Example 7 257.2/75.0 62.7 262.2 28.5 270.2/10.5 273.6/1.07 0.268 281.7/156.4 0.642 Example 8 258.5/75.0 60.2 263.0 25.8 270.6/10.2 273.9/1.02 0.274 282.4/148.6 0.647 Comparative 256.1/75.0 74.9 262.7 30.9 272.9/10.3 274.8/1.00 0.285 283.8/165.2 0.646 Example 1 Comparative 256.8/75.0 63.7 262.5 22.1 272.6/10.0 275.8/1.12 0.289 283.0/158.2 0.644 Example 2 Comparative 256.6/75.0 73.3 262.3 31.6 273.2/10.6 274.8/1.14 0.283 283.2/165.0 0.645 Example 3 Comparative 256.9/75.0 71.0 262.5 29.1 272.8/10.2 274.5/1.10 0.287 283.0/155.7 0.643 Example 4 Note: Intrinsic viscosity is measured in a mixed solvent of phenol:tetrachloroethane = 3:2 (V/V)

Comparative Example 5

(76) The present comparative example provides a method for preparing PET, which is basically the same as that of Example 3, by only differing in that: no esterification catalyst, tracer, and composite stabilizer were added.

Comparative Example 6

(77) The present comparative example provides a method for preparing PET, which is basically the same as that of Example 3, by only differing in that: the esterification catalyst was added, while no tracer and composite stabilizer were added.

Comparative Example 7

(78) The present comparative example provides a method for preparing PET, which is basically the same as that of Example 3, by only differing in that: a ethylene glycol antimony catalyst was used, while no tracer, esterification catalyst, and composite stabilizer were added.

Comparative Example 8

(79) The present comparative example provides a method for preparing PET, which is basically the same as that of Example 3, by only differing in that: the polymerization monomers were EG and PTA obtained by the petrochemical method, and a ethylene glycol antimony catalyst was used, while no tracer, esterification catalyst, and composite stabilizer were added.

(80) The use of each additive agent is shown in Table 7 below.

(81) TABLE-US-00007 TABLE 7 Additive agent using Esterification catalyst (zinc acetate, lithium Polymerization Stabilizer 2 Stabilizer 3 acetate, Tracer 2 catalyst Stabilizer 1 Sodium Triphenyl manganese Tracer 1 Solid phase (titanium No. Triethanolamine bisulfite phosphite acetate) (qualitative) (qualitative) series) Example 3 35 ppm 15 ppm 135 ppm 110 ppm 0 50 ppm 8 ppm Example 4 35 ppm 15 ppm 135 ppm 110 ppm 0 100 ppm 8 ppm Example 5 35 ppm 15 ppm 135 ppm 110 ppm 60 ppm 50 ppm 8 ppm Example 6 35 ppm 15 ppm 135 ppm 110 ppm 80 ppm 80 ppm 8 ppm Example 7 35 ppm 15 ppm 135 ppm 110 ppm 75 ppm 100 ppm* 8 ppm Example 8 35 ppm 15 ppm 135 ppm 110 ppm 75 ppm* 100 ppm* 8 ppm Comparative 8 ppm Example 5 Comparative 110 ppm 8 ppm Example 6 Comparative 210 ppmSb Example 7 Comparative 210 ppmSb Example 8 Note: Tracer 1: 2,2,4,4-tetramethylcyclobutanedicarboxylic acid, *pentaerythritol; Tracer 2: nano barium sulfate, *sub-nanometer composite calcium carbonate-magnesium carbonate (calcium: 40 ppm, magnesium: 60 ppm, total: 100 ppm)

(82) The semi-dull PET polyester prepared in each of the above examples and comparative examples was tested for performance, and the results are shown in Table 8 below, wherein the intrinsic viscosity was measured in a mixed solvent of phenol and tetrachloroethane (3:2 V/V).

(83) TABLE-US-00008 TABLE 8 Performance of semi-dull PET polyester dulling Intrinsic Melting DEG End carboxyl Hue Hue agent Ash viscosity point content content L B content content No. (dl/g) 3:2 C. (%) (mgKOH/Kg) value value (%) (%) Example 3 0.642 258.7 1.28 27.6 81.2 3.7 0.301 0.0 Example 4 0.640 258.4 1.31 28.2 80.9 3.4 0.300 0.0 Example 5 0.645 258.2 1.30 27.5 81.5 3.6 0.297 0.0 Example 6 0.641 258.9 1.26 28.3 79.8 4.0 0.303 0.0 Example 7 0.642 257.9 1.29 29.0 80.3 3.4 0.295 0.0 Example 8 0.647 258.3 1.32 27.6 81.0 3.8 0.298 0.0 Example 5 0.644 257.2 1.38 33.6 78.7 6.9 0.305 0.0 Example 6 0.645 257.6 1.33 27.9 79.2 7.3 0.301 0.0 Example 7 0.642 257.7 1.26 34.2 78.4 5.8 0.299 0.01 Example 8 0.643 259.3 1.27 28.7 83.8 2.6 0.302 0.0

(84) As shown in Table 8, compared with the petrochemical EG raw material (Comparative Example 8), the performance index of polyester prepared from the green EG is obviously different from that of polyester prepared from the petrochemical EG, and the main reason is by-products of the ethylene glycol produced by hydrogenation of carbon dioxide to prepare methanol are higher than those of the petrochemical ethylene glycol. By using the specific esterification catalyst and the composite stabilizers, the performance index of polyester produced 10 by the present disclosure is basically the same as that of polyester produced by petrochemical process.

(85) The melt direct spinning process is used to spin 83.3 dtex/144f and 55.5 dtex/72f FDY fibers, and the green carbon reduction polyester fiber prepared from the green ethylene glycol meets the market requirements and is basically the same as the 5 polyester fiber synthesized from the petrochemical ethylene glycol.

(86) TABLE-US-00009 TABLE 9 83.3dtex/144f FDY fiber physical and chemical index Boiling Oil Yarn water Strength/ content/ evenness shrinkage Interlacing No. Specification Fineness cN/dtex Elongation/% % CV % rate/% point Example 3 83/144 82.7 3.91 35.76 1.02 0.93 6.5 10 Example 4 83/144 82.6 3.90 35.17 1.07 0.95 6.6 9 Example 5 83/144 83.1 3.92 35.58 1.01 0.96 6.7 10 Example 6 83/144 82.9 3.89 35.40 0.99 0.90 6.3 11 Example 7 83/144 83.5 3.86 35.62 1.03 0.95 6.5 10 Example 8 83/144 83.6 3.85 35.98 1.00 0.92 6.9 10 Comparative 83/144 82.7 3.90 35.88 1.01 0.94 6.4 12 Example 5 Comparative 83/144 83.4 3.84 36.15 1.03 0.96 6.4 11 Example 6 Comparative 83/144 82.9 3.87 36.35 1.04 0.93 6.5 10 Example 7 Comparative 83/144 83.2 3.89 36.22 1.07 0.94 6.7 10 Example 8 Note: Comparative Example 8 is the polyester fiber produced from the petrochemical EG and PTA

(87) Table 10 below is the quality index of the 55.5 dtex/72f FDY fiber.

(88) TABLE-US-00010 TABLE 10 55.5dtex/72f FDY fiber physical and chemical index Boiling Oil Yarn water Strength/ Elongation/ content/ evenness shrinkage Interlacing No. Specification Fineness cN/dtex % % CV % rate/% point Example 3 55/72 55.7 3.98 33.50 1.05 1.26 7.2 14 Example 4 55/72 54.9 4.01 33.17 1.07 1.24 7.3 14 Example 5 55/72 55.2 3.96 32.58 1.08 1.22 7.1 13 Example 6 55/72 55.0 3.98 33.10 1.03 1.28 7.5 14 Example 7 55/72 54.8 3.89 32.64 1.09 1.30 7.2 14 Example 8 55/72 55.7 4.02 32.98 1.03 1.25 7.2 15 Comparative 55/72 55.6 3.97 32.81 1.01 1.24 7.4 14 Example 5 Comparative 55/72 55.7 4.02 32.75 1.08 1.26 7.3 14 Example 6 Comparative 55/72 54.9 3.82 33.72 1.04 1.28 7.2 14 Example 7 Comparative 55/72 55.8 4.06 32.53 1.07 1.24 7.1 14 Example 8 Note: Comparative Example 8 is the polyester fiber produced from the petrochemical EG and PTA

(89) The fiber is woven into a fabric, and after printing and dyeing, the fabric is subjected to tracking detection, and the detection results are as shown in Table 11.

(90) TABLE-US-00011 TABLE 11 Fabric tracking detection Tracer 1 Detection result Tracer 1 (nuclear magnetic Tracer 2 Tracer 2 Liquid phase resonance absorption Solid phase Detection No. (qualitative) characteristic peak) (quantitative) result Example 3 0 None 50 ppm 42 ppm Example 4 0 None 100 ppm 87 ppm Example 5 60 ppm Yes 50 ppm 39 ppm Example 6 80 ppm Yes 80 ppm 68 ppm Example 7 75 ppm Yes 100 ppm 85 ppm Example 8 75 ppm* Yes 100 ppm* 85 ppm* Comparative None None Example 5 Comparative None None Example 6 Comparative None None Example 7 Comparative None None Example 8 Note: Tracer 1: 2,2,4,4-tetramethylcyclobutanedicarboxylic acid, *pentaerythritol; Tracer 2: nano barium sulfate, *sub-nanometer composite calcium carbonate-magnesium carbonate (calcium: 40 ppm, magnesium: 60 ppm, total: 100 ppm)

(91) It can be seen that the tracer can be used for green carbon chemistry tracking.

(92) The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent change or modification made according to the essence of the present application should be covered in the protection scope of the present application.