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

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.