Stochastic optimisation method of simulated annealing (SA) type is presented. In the first part, the description of optimisation procedure is given. It is based on the application of simplex algorithm in the SA framework and aimed at solving nonlinear optimisation problems. A critical review of approaches proposed in the literature for realization of basic steps of SA algorithm is also given. A short review of some applications of SA optimisation technique for chemical and process engineering problems is included.