An 86 MW bottoming cycle has been designed based on the Kalina cycle principles previously reported by the authors. It is designated as Kalina Cycle System 6 (KCS6). It uses an ABB Type 13E gas turbine topping cycle to produce a 227 MW combined cycle having a heat rate (LHV) of 6460 Btu/kWh (52.8%). The working fluid is a 75% aqua ammonia mixture.
Equipment and installation costs were developed for KCS6 and a baseline two-pressure steam bottoming cycle. The KCS6 turbine was designed with input from ABB.
Compared to the two-pressure steam bottoming cycle, KCS6 provides an additional 12.1 MW (16.4%). The estimated cost of the bottoming cycle is $1,058/kW vs. $1,033/kW for the steam plant. The KCS6 heat acquisition equipment (boiler and recooler) and distillation/condensation subsystem represent the two major additions to cost over the steam plant. On the other hand, the turbine is less expensive, mostly due to the elimination of the large condensing stages.
An economic analysis of the KCS6 plant is presented using the value of the additional output as the decision-making economic variable. The analysis is based on a model which considers capital cost, heat rate and near-term world-wide fuel prices. At $4.25/106 Btu fuel, the KCS6 costs approximately $7 million less than the value of its output.