Optimization model for EL-TO Zagreb cogeneration plant

Abstract

A mathematical model for the cost optimization of the EL-TO Zagreb thermal power plant has been developed. The plant supplies hot water for district heating, process steam for industry and electric power. The rather detailed mathematical model of the plant includes models of all main components like gas turbine facilities with heat recovery boilers, high pressure steam generators, back-pressure turbines, peak load boilers and other equipment like heat exchangers, deaerators and pressure reduction valves. All boilers can use alternatively natural gas or heavy oil as fuel while gas turbines are supplied with natural gas only. The generalized reduced gradient method was used for solving the strongly nonlinear optimization problem. The goal of the mathematical model was to minimize the production cost by satisfying the district heat and industrial steam consumption. Results of the sensitivity analyses of the influence of extraction steam pressure levels on cost function are presented as well as a comparison of optimization results with operational data.