Optimization & thermodynamic, environmental and economic analysis of kalina cycle integrated for waste heat recovery in an existing steam generation system in different operating conditions

With the developing technology, the demand for energy is increasing day by day. The increasing need for energy has brought with it the need to find new resources and design new cycle technologies that will increase the efficiency of existing systems. Today, the main interest of researchers is focused on developing a new combined system to use energy resources more efficiently. The amount of waste heat that is not used efficiently and wasted in the industry is quite high. With the recovery of these waste heats; both energy is produced and CO2 emission is reduced. The Kalina cycle, which uses ammonia-water mixture as the cycle fluid, is one of the systems that provide the most efficient recovery of low-temperature waste heat. Compared ORC that another low waste heat recovery cycle with KC, better results were obtained using KC in terms of net power and thermal efficiency. In addition, the ammonia-water mixture is environmentally friendly and cheap compared to organic fluids is one of the reasons for KC's preference. In this thesis, the Kalina cycle is integrated into an existing burner that uses waste chips as fuel to generate steam and dry the moist fiber. Two different simulations were made for the Kalina cycle according to the conditions called Case-1 and Case-2. The Kalina cycle was analyzed using the first and second laws of thermodynamics and thermally optimized according to these two different simulation results. In the Case-1 simulation, the turbine outlet pressure is kept at a constant value for different ammonia-water concentrations, as in some studies in the literature, while in the Case-2 simulation; the turbine outlet pressure is kept variable for each concentration. Both cases were investigated depending on both turbine inlet temperature (from saturated liquid temperature at 50 bar to 330 °C) and increasing ammonia-water concentration (from X = 20% to X = 80%). Energy, exergy, economic and environmental analyzes were carry out for the Kalina cycle. At the same time, the thermal and exergy efficiencies of the cogeneration system formed by integrating the Kalina cycle were calculated. Maximum net power, thermal and exergy efficiencies obtained from Kalina cycle Case-1 at X=80%, T=330°C, respectively; 349.39kW, 22.70%, 52.60%. Maximum net power, thermal and exergy efficiencies obtained from Kalina cycle Case-2 X=20% at T=330°C, respectively; 380.97kW, 26.58%, 60.34%.