Air Separation Unit 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 integration of thermal needs and sinks, particularly in incorporating the Air Separation Unit into the condensate cycle, which affects overall plant efficiency and energy utilization.
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 Air Separation Unit dryer regenerator, with a cold reheat line and control valves to manage steam pressure and temperature for efficient regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the Air Separation Unit is integrated into the condensate cycle, then overall plant thermal efficiency is improved, but the system complexity increases
Solution Approach 1:
The patent merges the Air Separation Unit thermal requirements with the existing condensate heating system by integrating the dryer regenerator into the condensate cycle. Steam extracted from the turbine is used to heat the molecular sieve dryer, and the heated condensate is returned to the feedwater system, combining two separate thermal needs into one integrated system.
Solution Approach 2:
The condensate heating system serves dual purposes: it heats condensate for feedwater preparation and simultaneously provides thermal energy for the Air Separation Unit dryer regenerator. The steam extraction system also serves multiple functions by providing process heat for both the feedwater heaters and the dryer regenerator.
2Loss of energy
If steam extraction is used to heat the dryer regenerator, then energy waste is reduced, but the control system complexity increases
Solution Approach 1:
The patent incorporates control valves and instrumentation that monitor steam flow, condensate temperature, and dryer regenerator performance. The system uses feedback control to adjust steam extraction rates and condensate flow to maintain optimal thermal efficiency while meeting the drying requirements of the molecular sieve.
Solution Approach 2:
The condensate system self-regulates by using the extracted steam to heat the condensate, which then flows through the dryer regenerator before returning to the feedwater system. The thermal energy that would otherwise be wasted is automatically captured and reused, reducing energy loss without requiring complex external control systems.
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 the thermal efficiency of the power plant by optimizing heat usage and reducing energy waste, allowing for flexible plant operation and improved overall thermal efficiency.
Implementation Method 1
a dryer regenerator with a dryer heater wherein an extraction line connects the steam extraction port to the dryer heater
Implementation Method 2
a condenser adapted to condense steam exhausted from the low pressure steam turbine
Data Source
Figure 1~2
Figure 3~4
AI summary
Provided is a scheme for thermally integrating an Air Separation Unit into a coal fired oxy boiler power plant. Air Separation Unit has a Dryer with a dryer heater (5) wherein an extraction fine (4) connects the steam extraction port (2) to the dryer heater (5). A drain line (8) of the dryer heater (5) then fluidly connects the regeneration heater to a point of the Rankine steam cycle fluidly within the condensate system..