Hybrid Electrostatic and Wall Flow Filter for High-Temperature Gas

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Solution Overview

Problem

Existing electrostatic filters and bag/ceramic candle filters face inefficiencies in high-temperature applications and require high installation and maintenance costs, failing to meet stringent particulate emission standards, especially when dealing with gases from industrial processes like coal boilers and cement works.

Innovation Solution

A compact filter apparatus combining an electrostatic precipitator with wall flow filtering cells and a regeneration system, positioned in the outlet hood of the electrostatic filter, achieving high filtration efficiency and low installation costs by using silicon carbide materials capable of operating at high temperatures up to 600°C, and incorporating a counterflow compressed air pulse regeneration system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If electrostatic precipitators are used for gas dedusting, then the system can operate at high temperatures, but the dust removal efficiency does not meet stringent emission standards

Engineering Contradiction:
Improveoperating temperatureVSAvoiddust removal efficiency
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent combines an electrostatic precipitator with a bag filter in a hybrid configuration. The electrostatic precipitator performs primary dedusting at high temperatures, while the bag filter provides secondary filtration to achieve the required emission standards. This merging of two different filtration mechanisms allows the system to maintain both high-temperature operation capability and high dust removal efficiency.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If bag filters are used for gas dedusting, then the dust removal efficiency is high, but the installation and maintenance costs are high

Engineering Contradiction:
Improvedust removal efficiencyVSAvoidinstallation and maintenance costs
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of using a complete bag filter system throughout, the patent applies bag filtering only partially - specifically in the form of bagged hoppers at the collection points. This partial application provides sufficient additional filtration to meet emission standards while significantly reducing the overall cost compared to a full bag filter system.

Inventive Principle:
Principle #16Partial or excessive action

3Temperature

If ceramic candle filters are used for high temperature applications, then the temperature resistance is good, but the overall size and installation costs are high

Engineering Contradiction:
Improvetemperature resistanceVSAvoidoverall size
Core Design Contradiction:
TemperatureVSVolume of stationary object

Solution Approach 1:

The patent extracts the high-temperature filtration function from expensive ceramic candle filters and implements it instead through a combination of electrostatic precipitation and bagged hoppers. This extraction allows the system to maintain temperature resistance capability while dramatically reducing the overall size and installation costs associated with ceramic candle filter systems.

Inventive Principle:
Principle #2Taking out (Extraction)

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 achieves dust removal efficiencies of 90-99% at significantly lower installation and maintenance costs compared to traditional systems, effectively meeting stringent emission standards while maintaining operational reliability and efficiency across high-temperature industrial applications.

Implementation Method 1

electrostatic precipitators, by means of a difference of potential induced between the emitting and collecting electrodes, achieve the separation of the contaminated particles from the carrier gas

Methodology Applied
Scientific EffectElectrostatic charge induction: Electrostatic Induction

Implementation Method 2

achieve the separation of the contaminated particles from the carrier gas which is made to flow between the electrodes

Methodology Applied
Scientific EffectElectrostatic deposition: Electrostatic Deposition

Implementation Method 3

the dust is separated from the fumes by means of a proper filtering effect, obtained by making the gaseous current cross through fabric bags (tubular, 150 mm in diameter, 6000-8000 mm long) consisting of microporous felts

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Implementation Method 4

The filtering effect is provided, firstly, by the small size of the pores of the felt which allows the passage of the gas but not of the dusty particles

Methodology Applied
Scientific EffectPorosity: Porosity

Implementation Method 5

the bags themselves must be cleaned, e.g. by means of counterflow compressed air jets

Methodology Applied
Scientific EffectPneumatic cleaning: Pulse Jet

Implementation Method 6

incorporating a counterflow compressed air pulse regeneration system

Methodology Applied
Scientific EffectCompressed air pulse: Pulse Jet

Data Source

PatentEP3423191B1Gas dedusting filter apparatus and process
Publication Date: 2021.12.15 ECOSPRAY TECH
  • EP3423191B1 patent drawingFigure 1
  • EP3423191B1 patent drawingFigure 2
  • EP3423191B1 patent drawingFigure 3

AI summary

The present invention relates to a filter apparatus (1) for dedusting gas comprising one or more electrostatic precipitators (100), in each of said electrostatic precipitators (100) there being inserted at least one filtering unit (300) comprising, in turn, a plurality of filtering cells (301), e.g. of the wall flow type. The present invention also relates to a dedusting process for treating industrial gas. In particular, the dedusting process according to the present invention implemented by the filter apparatus having improved dusting efficiency, which is the object of the present invention, allows the treatment of gas coming from industrial processes, such as coal boilers, cement works, incinerators and like.