Wall-flow Honeycomb Catalyst for Flue Gas Dust Removal and Denitrification
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Solution Overview
Problem
Current flue gas treatment processes require separate systems for dust removal and denitrification, leading to high costs, large space requirements, and inefficient pollutant removal, especially for low-dust flue gas, due to the limitations of existing catalysts with non-uniform dispersion, high abrasion, and low efficiency.
Innovation Solution
A wall-flow honeycomb catalyst is developed using a mixture of calcined and crude titanium dioxide, boehmite, fused silica powder, dextrin, machine oil, and vanadium-molybdenum composite oxide, which is extrusion-molded and sintered to create a catalyst with enhanced mechanical strength and distribution, allowing for efficient dust removal and low-temperature denitrification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate systems are used for dust removal and denitrification, then each function can be optimized independently, but the floor space, investment cost, and system complexity increase significantly
Solution Approach 1:
The patent combines dust removal and denitrification functions into a single integrated catalyst system. The wall-flow honeycomb structure serves dual purposes: filtering dust particles while the coated denitrification catalyst treats nitrogen oxides. This merging eliminates the need for separate treatment systems, reducing floor space, investment cost, and system complexity while maintaining effective dust removal and denitrification performance
Solution Approach 2:
The wall-flow honeycomb catalyst is designed as a multi-functional device that simultaneously performs dust removal through physical filtration and denitrification through catalytic conversion. The honeycomb structure provides both the mechanical filtering capability for dust particles and the support structure for denitrification catalyst coating, enabling one device to fulfill multiple pollution control functions that previously required separate systems
2Adaptability or versatility
If a filter cartridge or filter bag is coated with denitrification active substance, then dust removal and denitrification can be integrated, but the catalyst dispersion becomes non-uniform and abrasion resistance decreases
Solution Approach 1:
The patent employs a wall-flow honeycomb structure with controlled pore sizes and distributions as the substrate. This porous ceramic structure provides a rigid framework that maintains structural integrity while allowing uniform catalyst distribution across the walls. The honeycomb geometry ensures consistent flow distribution and catalyst exposure, preventing the non-uniform dispersion issues encountered with flexible filter cartridges or bags
Solution Approach 2:
The patent uses a composite structure combining a ceramic honeycomb substrate with denitrification catalyst coating. The ceramic material provides mechanical strength and structural stability, while the catalyst layer delivers denitrification activity. This composite approach enhances both the uniformity of catalyst distribution and the overall abrasion resistance compared to coating flexible filter materials
3Temperature
If existing catalysts are used for low-temperature denitrification, then denitrification can be achieved at low temperatures, but the dust removal efficiency and catalyst life are compromised
Solution Approach 1:
The patent optimizes multiple parameters including honeycomb pore size distribution, wall thickness, and catalyst composition to achieve low-temperature denitrification while extending catalyst life. The specific pore size range and wall geometry are designed to maximize surface area for catalyst deposition and optimize flow patterns, ensuring efficient dust removal and sustained catalytic activity at low temperatures without premature catalyst degradation
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 catalyst achieves high dust removal efficiency (over 95%) and denitrification activity at 160° C. to 200° C., with a long lifespan and low production costs, integrating dust removal and denitrification in a single system suitable for industries like glass and coking after semi-dry/dry desulfurization.
Implementation Method 1
wall-flow honeycomb catalyst for dust removal
Implementation Method 2
vanadium-molybdenum composite oxide... high denitrification activity at 160° C. to 200° C.
Implementation Method 3
subjecting the filter unit to high-temperature sintering to obtain the catalyst
Data Source
AI summary
A wall-flow honeycomb catalyst for dust removal and low-temperature denitrification of flue gas, and a preparation process thereof are provided. The catalyst is prepared from the following raw materials in parts by weight: calcined titanium dioxide: 30 to 60 parts; crude titanium dioxide: 30 to 50 parts; boehmite: 3 to 5 parts; fused silica powder: 2 to 4 parts; binder: 0.5 to 2 parts; lubricant: 0.5 to 2 parts; vanadium-molybdenum composite oxide: 5 to 10 parts; and water: 150 to 200 parts; and the vanadium-molybdenum composite oxide is obtained by dissolving ammonium metavanadate and ammonium molybdate in an oxalic acid solution and spray-drying a resulting solution. The preparation process of the catalyst of the present disclosure is simple and low in cost.