Convection Section Cleaning Device for Thermal Power Plants
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Solution Overview
Problem
In thermal power plants, especially those using waste or biomass fuels, the existing cleaning methods for heating surfaces in the convection section face challenges such as inadequate steam kinetic energy, increased corrosion risk, and difficulty in removing residues due to water vapor treatment, leading to inefficient heat transfer and mechanical cleaning requirements.
Innovation Solution
A cleaning device with a lance and liquid distribution system that uses a pressure-sensitive switch to maintain liquid flow through the lance, ensuring water remains in a liquid state during long distances and high temperatures, and includes a path correction device for precise liquid delivery, allowing for effective and gentle cleaning of heating surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If steam is used for cleaning heating surfaces in the convection section, then cleaning action is provided, but the kinetic energy is insufficient and corrosion risk increases
Solution Approach 1:
The patent changes the physical state parameter of the cleaning medium from vapor (steam) to liquid (water). This parameter change provides sufficient kinetic energy for effective cleaning while avoiding the corrosion problems associated with steam at high temperatures
Solution Approach 2:
The patent replaces the thermal-based cleaning system (steam) with a mechanical-based system (pressurized liquid jet). The liquid is delivered under high pressure through a lance to provide mechanical cleaning action without the thermal effects of steam
2Productivity
If water is used to treat residues on heating surfaces, then residue removal is attempted, but water evaporates before reaching the surface at long distances
Solution Approach 1:
The patent uses hydraulic principles to deliver liquid water under high pressure through a lance over long distances. The pressurized liquid flow maintains its liquid state and delivers sufficient kinetic energy to the heating surfaces for effective residue removal
Solution Approach 2:
The liquid is pressurized before delivery through the lance, preparing it in advance to maintain liquid state and deliver sufficient impact force at the heating surfaces, preventing evaporation during transit
3Reliability
If mechanical knockers or sootblowers are used for cleaning, then heating surfaces are cleaned, but structural complexity and control technology requirements increase
Solution Approach 1:
The patent extracts the essential cleaning function from complex mechanical sootblower systems and implements it through a simpler pressurized liquid delivery system. The lance with liquid distribution device provides cleaning action without the mechanical complexity of rotating components or complex control systems
Solution Approach 2:
The pressurized liquid system provides self-regulating cleaning action where the liquid pressure and flow automatically adapt to the cleaning requirements, reducing the need for complex control technology and mechanical adjustments
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
The solution enables continuous liquid flow through the lance, preventing evaporation and ensuring effective residue removal, reducing corrosion risks and extending maintenance intervals, while maintaining structural simplicity and reducing control technology requirements.
Implementation Method 1
the liquid supply system in the lance forms a pressure-sensitive switch which yields at a predetermined pressure level, so that a liquid can flow through the pressure-sensitive switch to the liquid distribution device
Implementation Method 2
the impact of the discharged blowing medium on the debris accumulated on the heating surface generates a temperature shock as well as a mechanical shock intended to loosen the debris
Implementation Method 3
The temperature of the flue gas is reduced via these convective heating surfaces and at the same time the energy given off by the flue gas is transferred in the form of heat to a cooling medium circuit
Implementation Method 4
ensuring water remains in a liquid state during long distances and high temperatures
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a cleaning device (1) comprising at least: a holder (2), a lance (3) having a fluid distribution device (4), a drive unit (5) for a translational motion of the lance (3) in the holder (2), and a fluid conducting system (6) having a feed (7), a return (8), and flow paths (9) starting from the feed (7) to the return (8) and to the fluid distribution device (4), wherein at least one actuating means (10) is provided in order to connect the feed (7) to the return (8) or to the fluid distribution device (4) as needed. The invention further relates to a method for cleaning heating surfaces (23) of a convection section (18) of a thermal power plant (17) that comprise spaced heat exchanger pipes (21) using such a cleaning device (1).