Thermodynamic assessment of gasification and pyrolysis of marine algae to produce hydrogen-containing gas

Abstract

The article gives a thermodynamic assessment of modes of gasification and pyrolysis of algae of gross formulation C1H1.66O1.4 with obtaining hydrogen gas. The authors investigate the modes of air gasification and pyrolysis of algae at pressures of 0.1 MPa and 1 MPa with varying the fuel excess ratio and temperatures. In the case of gasification at a pressure of 0.1 MPa the hydrogen and carbon monoxide concentration increases with an increase of the fuel excess ratio (φ) from 2 to 10 and at φ = 10 and T = 1000 K reaches 25.95 mole % and 27.84 mole %, respectively. An increase in temperature from 1000 K to 1300 K leads to a decrease in the amount of hydrogen and an increase in carbon monoxide in the gaseous products. An increase in the operating pressure from 0.1 to 1 MPa at a gasification temperature of 1000 K leads to the formation of a small amount of methane (~ up to 5 mole %), a decrease in the mole content of hydrogen and carbon monoxide in the final products, and also to the formation of coke (at φ≥7), which we can use as a target product. The caloric value of the gases produced is higher in the pyrolysis of algae than in its gasification. The pressure increase at 1300 K has almost no effect on the equilibrium composition of the products in the gaseous products.