High-Temperature Single Machine Pulse Bag Filter (Coal/Fuel Biomass Applications)
I. Overview
This is a compact, integrated pulse bag dust collector specifically designed to handle high-temperature flue gases produced by coal-fired boilers, biomass burners (such as wood chips, straw, rice husks, etc.), and burners. It not only addresses the high-temperature issue but also deals with the complex chemical environment that arises, including acidic corrosion and火星 risks. Its goal is to achieve efficient, safe, and stable purification of high-temperature flue gases at the source or near the source.
Section II: Design Core: Withstanding High Temperatures and Special Challenges
The primary characteristics of flue gas from coal and biomass combustion determine the specialized design of the dust collector:
1. High Temperature: Flue gas temperatures are typically between 160℃ to 250℃, and may even exceed this momentarily.
2. High moisture content: The biomass fuel has significant fluctuations in moisture content, resulting in high humidity in the flue gas.
3. Acidic Gases: Produced by combustion (e.g., SO2, HCl), they form acid dew at low temperatures, causing corrosion.
4. Mars Risk: Unburned carbon particles and sparks are common, prone to burn through filter bags.
5. Sticky Dust: Biomass fly ash may contain low-melting-point alkali metal compounds such as potassium and sodium, which are prone to adhere to filter bags at high temperatures.
Section 3: Key Technologies and Special Designs
The high-temperature single-machine pulse dust collector requires the following key designs:
High-temperature-resistant core components
Filter Media Selection (The Core of the Core):
Special modified glass fiber filter material: withstanding high temperature up to 260°C, instant temperature up to 280°C, excellent antioxidant properties, resistant to short-term spark burning, high cost-performance ratio.
PPS (polysulfone): With a temperature resistance up to 190°C, it offers good resistance to acids and alkalis and is commonly used for biomass flue gas (when chlorine content is low), but it is not resistant to high oxygen levels.
PTFE: With a temperature resistance up to 250°C, it features chemical resistance and non-stick properties, making it ideal for dealing with highly corrosive and sticky dust. It can be made into pure PTFE filter material or used as a base fabric or coating for P84/PPS.
P84 (Polyimide): Withstanding temperatures up to 260°C, excellent high-temperature performance, and good capture properties. However, poor alkali resistance and high cost.
Selection Strategy: Based on flue gas temperature, composition (especially sulfur and chlorine content), and budget, a comprehensive choice is made for the most economical option.
High-temperature and chemically resistant filter media.
2. Structural Safety and Temperature Control Design
Shot Blasting/Rust Removal/Corrosion Prevention: Interior wall shot blasting to SA2.5 standard
Insulation of the cabinet: The entire cabinet (including the ash hopper) must be wrapped with sufficient thickness of insulating material (such as rock wool, aluminum silicate fiber blanket) to prevent the outer shell from becoming too cold, causing acid condensation and corrosion, and to ensure that the flue gas temperature remains above the crystallization point at all times.
Outer panel: The thermal insulation layer is covered with color steel plate, serving as protection and enhancing aesthetics.
Mixed Flow Valve (Wild Flow Valve): An automatic temperature control mixed flow valve is installed on the pipeline before the air inlet of the dust collector. When the flue gas temperature exceeds the allowable limit of the filter bags (e.g., set at 220℃), the valve automatically opens to draw in ambient cool air, lowering the temperature of the mixed gas to a safe range. This is the most crucial safety protection device.
Pre-ignition arrester: Install a cyclone or labyrinth arrester before the flue gas enters the deduster to effectively separate and settle most sparks and hot particles.
Explosion-proof Measures: In case of dust hazards (such as coal dust, wood dust), explosion-proof plates and pressure relief valves must be installed to rapidly release pressure during sudden pressure increases, protecting the main structure of the equipment.
Corrosion resistance and dust removal optimization.
Material Upgrade:
The housing and critical components can be made of weather-resistant steel or treated with heavy-duty anti-corrosion coatings. In areas with extremely high corrosion risks (such as clean gas chambers), stainless steel materials can be used.
Design of Ash Pan
The hopper angle is designed to be larger (typically ≥60°), with a smooth inner wall, and may include hopper wall vibrators or air cannons to prevent clogging of materials due to high humidity or dust adhesiveness.
Ash cleaning system optimization:
Utilize pulse valves suitable for high-temperature service conditions.
Ash removal strategy needs adjustment; adopt the principle of "small amounts and multiple times" to avoid excessive force during ash removal that damages the filter bags aged by high temperatures. At the same time, ensure thorough ash removal to prevent caking.