Method for enriching carbon dioxide and hydrogen by water-gas shift coupling of blast furnace gas

A method for enriching carbon dioxide and hydrogen by water-gas shift coupling of blast furnace gas, comprising following steps:

• purifying the blast furnace gas by a dry purification method, followed by heating and mixing with water gas, allowing for a water-gas shift coupling reaction under an action of a catalyst to obtain a mixed gas of the carbon dioxide and hydrogen;
• wherein components of the blast furnace gas comprise 15-30 vol. % CO2, 15-30 vol. % CO, 0.1-5 vol. % H2, 30-60 vol. % N2, 0-1.5 vol. % O2, 20-200 mg/m3 H2S, 20-160 mg/m3 COS, 2-6 vol. % water gas, 5-20 mg/m3 HCl, and 0.2-0.4 vol. % CH4;
• and
• the dry purification method is performed with a multilayer composite adsorbent that consists of alkali-modified activated carbon, molecular sieve and alumina;
• wherein the mass ratio of alkali-modified activated carbon:molecular sieve:alumina is (3-5):(3-5):2;
• wherein the blast furnace gas after purification has a concentration of 20 vol. % CO2, 25 vol. % CO, and 3 vol. % H2;
• a temperature of the blast furnace gas after purification is 160-220° C., a pressure is 0.18-0.3 MPa, and a temperature of the heating is 320-400° C.;
• the catalyst is an iron-based catalyst;
• and a space velocity of the water-gas shift coupling reaction is 400-1200 h−1;
• and
• after the water-gas shift coupling reaction, the water-gas shift coupling reaction is carried out again;
• and a temperature for carrying out the water-gas shift coupling reaction again is 200-250° C., with a catalyst of a copper-based catalyst, and a space velocity of 2000-3600 h−1.