Waste heat supply-side power regulation with variable concentration for turbine in Kalina cycle

The waste heat is usually considered as a free heat resource, thus the objective aim of power regulation for scheduled long term fluctuated waste heat driven power generation units should be waste heat supply-side control that generate as much as possible power which is quite different from the demand-side control of the conventional power plants. The variable concentration power regulation is a unique approach that based on the Kalina cycle by adjusting turbine inlet pressure with variable concentration of ammonia-water work solution to match work flow rate and to realize maximum possible power for achieving high efficiency without turbine throttling loss. A solution storage tank is set and charged with solution of either work or basic concentration, and the variable concentration in the system loop is realized with the seesaw effect balanced with that in the solution storage tank. Both the static and dynamic mathematical models were established to study the characteristics of the variable concentration regulation. The results showed that under certain condition, if the power output changes from 0.8 to 1 of the rated value, the volume of the solution tank should be 36% of the equivalent liquid volume of the system. The thermal efficiency of variable concentration regulating scheme is 12.8% higher than that of the scheme with turbine inlet valve throttling at 80% rated turbine flow rate.