Part-load performance of a high temperature Kalina cycle

Abstract

The Kalina cycle has recently seen increased interest as an alternative to the conventional steam Rankine cycle. The cycle has been studied for use with both low and high temperature applications such as geothermal power plants, ocean thermal energy conversion, waste heat recovery, gas turbine bottoming cycle and solar power plants. The high temperature cycle layouts are inherently more complex than the low temperature layouts due to the presence of a distillation-condensation subsystem, three pressure levels and several heat exchangers. This paper presents a detailed approach to solve the Kalina cycle in part-load operating conditions for high temperature (a turbine inlet temperature of 500• C) and high pressure (100 bar) applications. A central receiver concentrating solar power plant with direct vapour generation is considered as a case study where the part-load conditions are simulated by changing the solar heat input to the receiver. Compared with the steam Rankine cycle, the Kalina cycle has an additional degree of freedom in terms of the ammonia mass fraction which can be varied in order to maximize the part-load efficiency of the cycle. The results include the part-load curves for various turbine inlet ammonia mass fractions, and the fitted equations for these curves.

A review of recent research on the use of zeotropic mixtures in power generation systems

“…The results indicated that the highest rate of exergy destruction in the power cycle occurs in the receiver/boiler. The study was continued with a full thermoeconomic optimization [114,119] with the minimization of LCOE as the objective function by combining the detailed thermodynamic design [115] and the part-load models [116] in order to evaluate the cycle performance over a year. The results suggested that a Kalina cycle power system without storage cannot compete with the state-of-the-art steam Rankine cycle power system for high temperature solar power applications when considering both the thermodynamic and the economic aspects.…”

Thermoeconomic optimization of a Kalina cycle for a central receiver concentrating solar power plant

“…A methodology to obtain the nominal operating condition for the Kalina cycle KC12 was presented in detail by Modi et al [26]. The validation of the general solution algorithm for the high temperature Kalina cycles was also presented [26]. The following assumptions were made for the thermodynamic design of the Kalina cycle CSP plant [25,35].…”

“…3. In general, the following steps were used to solve the Kalina cycle for each iteration of the optimization process [26]. The turbine TUR was solved first to obtain the state at the turbine outlet.…”

“…The turbine TUR was solved first to obtain the state at the turbine outlet. Assuming a condenser pressure for the condenser CD2, the mass flow rates were then obtained using a simplified configuration as presented in Marston [17] and elaborated in Modi et al [26] for the KC12 layout. Once the mass flow rates at different points in the cycle were known, and it was made sure that the inlet stream to the separator SEP is in two-phase flow, then the pumps, the mixers, the recuperators, and the condensers were solved using the equations as presented in Modi et al [26], while satisfying all the design constraints.…”

“…Examples include their use in geothermal power plants [4], for waste heat recovery [5][6][7][8], for exhaust heat recovery in a gas turbine modular helium reactor [9], in combined heat and power plants [10,11], with a coal-fired steam power plant for exhaust heat recovery [12], as a part of Brayton-Rankine-Kalina triple cycle [13], and in solar plants [14][15][16]. For high temperature applications, the Kalina cycles have been investigated to be used as gas turbine bottoming cycles [17][18][19][20], for industrial waste heat recovery, biomass based cogeneration and gas engine waste heat recovery [21], for direct-fired cogeneration applications [22], and in CSP plants [23][24][25][26].…”