A method for preparing methanol by a hydrogenation reaction comprising carbon dioxide and hydrogen as raw materials to prepare the methanol, wherein:
- the hydrogenation reaction is carried out in a reaction system comprising two-stage fixed bed reactors in sequence, wherein:
- a first-stage fixed bed reactor comprises at least two reaction towers arranged in parallel, wherein each reaction tower of the first-stage fixed bed reactor is filled with a copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst, wherein:
- the copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst comprises:
- a supporting carrier, and
- an active component comprising copper oxide, zinc oxide, calcium oxide, magnesium oxide and aluminum oxide,
- wherein the copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst is columnar and comprises a porous structure;
- and
- a second-stage fixed bed reactor comprises at least one reaction tower, wherein each reaction tower of the second-stage fixed bed reactor is filled with a copper-zirconium-titanium-vanadium deposition hydrogenation catalyst wherein:
- the copper-zirconium-titanium-vanadium deposition hydrogenation catalyst comprises:
- a supporting carrier comprising graphite, activated carbon and a binder,
- a nano silicon dioxide carrier, and
- a porous deposition catalyst layer on a surface of the nano silicon dioxide carrier, the porous deposition catalyst layer comprising copper oxide, zirconium oxide, titanium oxide and vanadium oxide,
- wherein the copper-zirconium-titanium-vanadium deposition hydrogenation catalyst is columnar and comprises a porous structure;
- wherein each of the first-stage fixed bed reactor and the second-stage fixed bed reactor comprise:
- an inner chamber comprising an inner circumference and an outer circumference and a plurality of horizontal arranged trays inside the inner circumference of the inner chamber, and
- an outer chamber comprising an outer circumference and an inner circumference, wherein the inner circumference of the outer chamber surrounds the outer circumference of the inner chamber, wherein:
- a top, a middle and a bottom of the outer chamber comprise a plurality of groups of homogenizing trays, and
- a filter screen is arranged at the bottom of the outer chamber between the outer circumference and the inner circumference of the bottom chamber;
- filling the copper-zinc-calcium-magnesium-aluminum hydrogenation catalyst between the inner chamber and the homogenizing trays of the outer chamber of the first-stage fixed bed reactor;
- filling the copper-zirconium-titanium-vanadium deposition hydrogenation catalyst between the inner chamber and the homogenizing trays of the outer chamber of the second-stage fixed bed reactor;
- and
- hydrogenating the carbon dioxide to form methanol, wherein:
- a pressure of the first-stage fixed bed reactor is from 5.0-15.0 MPa;
- a pressure of the second-stage fixed bed reactor is from 10.0-17.5 MPa;
- and
- a reaction selectivity of methanol after the hydrogenation reaction of the second-stage fixed bed reactor is completed is more than 97.0%.