Sootblower Lance Tube Cooling via Temperature Feedback
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Solution Overview
Problem
Kraft boilers face significant inefficiencies due to continuous sootblowing processes that consume large amounts of steam and are ineffective in preventing ash buildup on superheater surfaces, leading to reduced heat transfer and frequent boiler shutdowns for cleaning.
Innovation Solution
A cleaning system for heat transfer surfaces in boilers that uses sootblowers with a temperature measuring system to control steam flow, adjusting it based on wall temperature measurements to minimize steam usage during cleaning and cooling strokes, thereby preventing excessive temperature and reducing residual ash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous sootblowing is performed to remove ash deposits from superheater surfaces, then ash removal effectiveness is improved, but steam consumption increases significantly
Solution Approach 1:
The sootblower system dynamically adjusts steam flow rate based on real-time temperature measurements from the lance tube. The control system modulates the steam valve to maintain optimal cleaning effectiveness while minimizing steam consumption, transitioning from continuous fixed-flow operation to variable-flow operation responsive to actual thermal conditions.
Solution Approach 2:
A temperature sensing system continuously monitors lance tube temperature and feeds this information back to the control system. The feedback loop enables automatic adjustment of steam flow rates, allowing the system to maintain effective ash removal while consuming less steam by reducing flow when full power is not needed.
2Productivity
If high steam flow rate is used during sootblowing to ensure effective cleaning, then ash deposit removal is improved, but thermal energy loss increases
Solution Approach 1:
The system applies partial steam flow rather than continuous high-flow steam during sootblowing operations. By using temperature feedback to determine when and how much steam is actually needed for effective cleaning, the system avoids excessive steam application, thereby maintaining productivity while reducing thermal energy loss to acceptable levels.
3Reliability
If sootblowing operates at predetermined intervals regardless of actual need, then cleaning coverage is improved, but steam waste increases
Solution Approach 1:
The sootblower system monitors its own thermal conditions through temperature sensors and automatically determines when cleaning is actually needed. This self-service capability allows the system to operate based on real conditions rather than fixed schedules, ensuring cleaning coverage is maintained while eliminating steam waste from unnecessary blowings.
4Ease of operation
If lance tube temperature is not controlled, then operational simplicity is maintained, but tube softening and plugging risk increases
Solution Approach 1:
The system replaces simple mechanical operation with automated thermal management using temperature sensors and electronic control. This substitution maintains ease of operation through automatic control while preventing tube plugging by actively monitoring and responding to temperature conditions that could lead to softening and deformation.
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 reduces steam consumption during cooling strokes, conserving energy and maintaining effective ash removal, thereby enhancing boiler efficiency and reducing the need for frequent shutdowns.
Implementation Method 1
A temperature measuring system is used for measuring and monitoring wall temperature of an annular wall of the tube during operation of the one or more sootblowers
Implementation Method 2
controlling a flow of steam or other cleaning fluid through the tube and nozzle during cleaning portions and cooling portions of the strokes... controlling the flow of steam during the cooling portions of the strokes to prevent the wall temperature measurements from exceeding a predetermined temperature limit
Data Source
AI summary
A cleaning system and method for cleaning heat transfer surfaces in a boiler using a temperature measuring system for measuring and monitoring wall temperature of an annular wall of the tube of a lance of one or more sootblowers. Controlling a flow of steam or other fluid through the tube during the cooling portions of the strokes based on wall temperature measurements from the temperature measuring system. Infrared or thermocouple temperature measuring systems may be used. The steam or other fluid may be flowed at a default flowrate that may be substantially zero until the temperature measuring system indicates the wall temperature of the annular wall begins to exceed a predetermined temperature limit which may be the softening point of the annular wall. Then the steam or other fluid is flowed at a rate greater than the default flowrate.