Steam Coil Oxygen Preheater Heat Integration in Oxy Boiler Plants
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Solution Overview
Problem
Existing coal-fired oxy boiler power plants face challenges in optimizing the heat integration of oxygen feed systems with the steam cycle, leading to inefficiencies and energy wastage, particularly in incorporating the steam coil oxygen preheater into the thermal cycle.
Innovation Solution
A novel heat integration scheme that thermally incorporates the Air Separation Unit into the condensate system of a coal-fired oxy boiler power plant, utilizing a steam extraction arrangement and condensate return scheme to supply heat to the oxygen feed line, with a steam coil oxygen preheater connected to the Rankine steam cycle, allowing for flexible plant operation and improved thermal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the steam coil oxygen preheater is integrated into the thermal cycle, then plant thermal efficiency is improved, but the system complexity increases
Solution Approach 1:
The patent merges the oxygen preheater system with the existing steam cycle by integrating the steam coil oxygen preheater into the condensate heating train. The preheater is connected between the condenser and the series of heaters, utilizing extraction steam from the steam turbines to heat oxygen. This integration combines two previously separate systems (oxygen preparation and steam cycle) into a unified thermal system, improving overall efficiency while managing complexity through systematic integration.
2Loss of energy
If heat integration is optimized, then energy wastage is reduced, but the difficulty of system integration increases
Solution Approach 1:
The patent applies preliminary action by preheating oxygen using extraction steam from the steam turbines before combustion. The oxygen preheater is positioned in the thermal cycle to receive heat from steam at various stages, preparing the oxygen for combustion in advance. This preliminary heating of oxygen improves energy utilization by recovering heat that would otherwise be wasted, while the integration points are strategically selected to minimize integration complexity.
3Adaptability or versatility
If the oxygen preheater is connected to multiple steam turbines, then flexibility of plant operation is improved, but the device complexity increases
Solution Approach 1:
The patent implements multi-functionality by designing the oxygen preheater system to accept steam from multiple sources - HP (high pressure), IP (intermediate pressure), and LP (low pressure) steam turbines. The preheater can draw steam from any or all of these sources depending on plant operating conditions, making the system adaptable to different load levels and operational scenarios. This universal design allows the same equipment to serve multiple functions across different operating regimes without requiring separate systems for each steam source.
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 integration enhances overall plant thermal efficiency by optimizing heat generation and utilization, reducing energy wastage, and enabling flexible plant operation by effectively linking the steam coil oxygen preheater with the condensate system, thereby improving the global heat rates and reducing emissions.
Implementation Method 1
it may be preferable to separately or additionally preheat oxygen from the Air Separation Unit in a steam coil oxygen preheater
Implementation Method 2
Exhaust steam from the last low pressure steam turbine LP is condensed in a condenser 102
Data Source
AI summary
A coal fired oxy boiler power plant is disclosed in which a steam coil oxygen preheater located on an oxygen line Air Separation Unit is thermally integrated with the condensate system. Thermal energy for the steam coil oxygen preheater is provided via an extraction line connected to a steam extraction port of an intermediate pressure steam turbine. A drain line of the steam coil oxygen preheater fluidly connects the steam coil oxygen preheater to a point of the Rankine steam cycle fluidly within the condensate system.