Metal Filter with Irregular Substrate for Low-Temp NOx Reduction
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Solution Overview
Problem
Conventional NOx reduction techniques for ship engines, such as extruded catalytic filters, fail to achieve NOx reduction efficiency of 85% or more at temperatures of 300°C or less, due to low cell density and decreased catalytic activity, which is insufficient to meet stringent emission regulations.
Innovation Solution
A metal filter with a metal substrate having irregularities coated with a low-temperature active catalyst composed of Ti-PILC, vanadium, tungsten, and alumina sol, enhancing NOx reduction efficiency and adhesion in the temperature range of 250°-300°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an extruded catalytic filter composed of vanadia and PILC is used, then the filter structure is simple and easy to manufacture, but the NOx reduction efficiency is below 85% at temperatures of 300°C or less due to low cell density and decreased catalytic activity
Solution Approach 1:
The patent changes the physical and chemical parameters of the catalyst by using a slurry coating method with specific composition ratios (vanadium 1-10 wt%, tungsten 1-5 wt%, alumina sol 5-20 wt%) and controlling drying and burning conditions (drying at 100-200°C for 1-10 hrs, burning at 400-600°C for 1-10 hrs) to achieve high NOx reduction efficiency of 85% or more at temperatures of 300°C or less
Solution Approach 2:
The patent creates a composite catalyst material combining vanadium, tungsten, alumina sol, and PILC in a slurry coating layer on the metal substrate. This composite structure provides both high catalytic activity for NOx reduction and good adhesion to the substrate, resolving the contradiction between ease of manufacture and high productivity
2Reliability
If the catalyst is coated on a metal substrate with irregularities, then the adhesion and bondability are enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by forming irregularities on the metal substrate surface before coating the catalyst slurry. The substrate is treated to create protrusions and depressions that enhance mechanical interlocking and adhesion of the catalyst layer, preventing catalyst separation during operation and extending filter lifetime
Solution Approach 2:
The patent utilizes porous materials by creating a slurry coating layer with controlled porosity and thickness (5-50 μm) that contains interconnected pores for catalyst activity while maintaining adhesion to the irregular substrate surface. The porous structure allows reactant access while the irregular substrate provides anchoring points
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 metal filter achieves NOx reduction efficiency of 85% or more at 250°-300°C, with superior adhesion and extended filter lifetime, effectively meeting regulatory standards and improving purification performance compared to conventional techniques.
Implementation Method 1
a filter for purifying exhaust gases by spraying a reductant such as ammonia or urea onto exhaust gases so that the exhaust gases are converted into harmless N2 and H2O via an active catalytic reaction
Implementation Method 2
the bondability of the applied low-temperature active catalyst is enhanced thanks to irregularities formed on the metal substrate, the metal filter of the invention can exhibit very superior adhesion and bondability in water
Data Source
AI summary
The present invention relates to a metal filter for purifying the exhaust gas from a ship, and a preparation method thereof. The purpose of the present invention is to provide: a metal filter for purifying the exhaust gas from a ship, capable of reducing nitrogen oxide by 85% or more at 250-300° C.; and a preparation method thereof. The metal filter for removing nitrogen oxide contained in the exhaust gas from a ship of the present invention comprises an integrated catalyst, wherein a metal substrate comprising irregularities is coated with a low temperature active catalyst in which vanadium (V), tungsten (W) and alumina sol are supported in a Ti-pillared clay (Ti-PILC) powdered support.