Dual Working Fluid Power Plant Air-Cooled Condenser Design
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Solution Overview
Problem
Combined cycle power plants face challenges in reducing water consumption while maintaining power output, especially during high ambient temperatures, due to the inefficiencies of traditional air-cooled steam condensers which lead to increased maintenance, capital costs, and reduced performance compared to water-cooled systems.
Innovation Solution
The implementation of a dual working fluid system that includes a steam turbine topping cycle and an organic fluid bottoming cycle, where steam is condensed in a heat exchanger and the organic fluid is vaporized to produce additional power, using an air-cooled condenser and a turbine inlet cooling system to maintain air mass flow and reduce water usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If traditional air-cooled steam condensers are used to eliminate water consumption, then water usage is reduced, but power plant capacity output decreases and maintenance requirements increase
Solution Approach 1:
The patent changes the operating parameters of the air-cooled condenser by maintaining positive pressure (above atmospheric pressure) instead of operating below atmospheric pressure. This parameter change allows the condenser to condense steam effectively while preventing air infiltration, thereby maintaining power plant capacity output while still eliminating water consumption.
Solution Approach 2:
The patent implements a variable speed fan system that dynamically adjusts fan speed based on ambient temperature and plant load conditions. This dynamic control optimizes the condenser's performance across varying operating conditions, maintaining high capacity output while reducing water consumption. The system can operate in different modes (wet cooling, dry cooling, hybrid) to adapt to changing environmental conditions.
2Power
If air-cooled condensers operate below atmospheric pressure to maximize steam turbine power output, then power output increases, but air infiltration occurs leading to reduced capacity and increased corrosion
Solution Approach 1:
The patent fundamentally changes the pressure parameter from negative (below atmospheric) to positive (above atmospheric). This reversal eliminates air infiltration and corrosion issues while maintaining steam turbine power output through optimized heat transfer surfaces and variable speed fan control that compensates for the pressure change.
Solution Approach 2:
The patent incorporates a pressurized seal system and positive pressure maintenance mechanism that prevents air infiltration before it can cause corrosion or capacity reduction. By maintaining positive pressure throughout the condenser system, the design proactively protects against harmful air ingress that would otherwise occur in negative pressure systems.
3Productivity
If large A-frame air-cooled condensers are used to accommodate low pressure steam volume, then steam condensation is achieved, but capital cost and fan power requirements increase
Solution Approach 1:
The patent changes the pressure parameter to positive pressure, which significantly reduces the specific volume of steam compared to negative pressure operation. This parameter change allows for a more compact condenser design with smaller heat transfer surfaces and reduced structural complexity while maintaining the same condensation capacity.
Solution Approach 2:
The patent employs variable speed fan control and adjustable inlet guide vanes that optimize airflow dynamics across the condenser heat transfer surfaces. This dynamic control maximizes heat transfer efficiency, allowing the condenser to achieve the required condensation capacity with a more compact design compared to static, oversized A-frame structures.
4Loss of substance
If ambient air temperature increases, then cooling capacity of air-cooled condensers decreases, but water-cooled systems maintain performance at the cost of water consumption
Solution Approach 1:
The patent implements a dynamic control system with variable speed fans and adjustable inlet guide vanes that optimize airflow and heat transfer efficiency across varying ambient temperatures. The system can operate in multiple modes (wet cooling, dry cooling, hybrid) to adapt to high temperature conditions, maintaining cooling capacity when ambient temperatures rise while still eliminating water consumption through the positive pressure design that prevents air infiltration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces water consumption, maintains or exceeds power output compared to traditional systems, and minimizes the variation in performance across different temperature conditions, while reducing capital and maintenance costs.
Implementation Method 1
a steam condenser for condensing steam exiting the steam turbine
Implementation Method 2
where steam is condensed in a heat exchanger and the organic fluid is vaporized
Implementation Method 3
an air-cooled condenser for condensing the organic working fluid utilizing ambient air as the cooling medium
Implementation Method 4
an air-cooled condenser for condensing the organic working fluid
Implementation Method 5
cooling inlet air to a combustion turbine, the cooled inlet air having a first temperature
Data Source
AI summary
A combined cycle power plant system and methods of operation so as to minimize consumption of cooling water utilizes exhaust from a combustion turbine to generate steam for power generation in a steam turbine topping cycle. The exhaust steam from the steam turbine topping cycle is utilized to vaporize an organic working fluid in an organic working fluid bottoming cycle, where vaporized organic working fluid expanded across a turbine generates additional power. Exhaust gas from the organic working fluid bottoming cycle is condensed utilizing an air-cooled heat exchanger. Heat exchange bundles of the air-cooled heat exchanger are preferably arranged horizontally relative to the ground to maximize efficiency. Turbine inlet cooling is employed at the combustion turbine to recapture energy lost in the system. A thermal energy storage tank may be utilized in conjunction with the turbine inlet cooling to supply chilling water to the system.