Gasoline blending is a key process in the petroleum refinery industry posed as a nonlinear optimization problem with heavily nonlinear constraints This paper presents a DNA based hybrid genetic algorithm (DNA-HGA) to optimize such nonlinear optimization problems In the proposed algorithm potential solutions are represented with nucleotide bases Based on the complementary properties of nucleotide bases operators inspired by DNA are applied to improve the global searching ability of GA for efficiently locating the feasible domains After the feasible region is obtained the sequential quadratic programming (SQP) is implemented to improve the solution The hybrid approach is tested on a set of constrained nonlinear optimization problems taken from the literature and compared with other approaches The computation results validate the effectiveness of the proposed algorithm The recipes of a short-time gasoline blending problem are optimized by the hybrid algorithm and the comparison results show that the profit of the products is largely improved while achieving more satisfactory quality indicators in both certainty and uncertainty environment (C) 2010 Elsevier B V All rights reserved