Ruthenium Titania-Tungsten Catalyst for NOx and SO3 Reduction
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Solution Overview
Problem
Current NOx and SO3 removal catalysts fail to completely suppress SO2 oxidation to SO3, leading to increased SO3 levels in discharge gases, causing corrosion and performance issues in boiler systems, necessitating additional countermeasures to prevent pressure loss.
Innovation Solution
A discharge gas treatment catalyst comprising a titania-tungsten oxide or titania-silica-based carrier with ruthenium, which prevents SO2 oxidation to SO3 and reduces NOx and SO3 levels by promoting their reduction to SO2 and N2, respectively, using ammonia as a reducing agent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional NOx removal catalysts (ammonia catalytic reduction method) are used, then NOx removal performance is improved, but SO2 oxidation to SO3 increases, causing corrosion and pressure loss
Solution Approach 1:
The patent introduces a specific catalyst composition (titania-tungsten oxide or titania-silica-tungsten oxide carrier with ruthenium) as an intermediary substance that mediates between the NOx reduction reaction and the harmful SO2 oxidation reaction. This catalyst selectively promotes NOx reduction while suppressing SO2 oxidation to SO3, thereby resolving the contradiction between achieving NOx removal performance and preventing SO3 formation
Solution Approach 2:
The patent changes the chemical parameters of the catalyst system by using specific combinations of titania, tungsten oxide, silica, and ruthenium in controlled proportions. These parameter changes in catalyst composition and structure enable the system to achieve high NOx removal efficiency while simultaneously suppressing the oxidation of SO2 to SO3, thus resolving the technical contradiction
2Object-affected harmful factors
If SO2 oxidation to SO3 is suppressed, then corrosion is reduced, but NOx removal efficiency may be compromised
Solution Approach 1:
The patent applies local quality by creating a catalyst with specific spatial distribution of active components. The ruthenium is carried on the titania-tungsten oxide or titania-silica-tungsten oxide carrier in a controlled manner, creating localized active sites that are highly selective for NOx reduction while avoiding sites that would promote SO2 oxidation. This local optimization allows simultaneous achievement of high NOx removal efficiency and low corrosion
3Reliability
If additional countermeasures are taken to prevent pressure loss, then system reliability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the root cause of the problem (SO3 formation from SO2 oxidation) and addresses it directly at the source through a specialized catalyst. By removing the harmful SO3 formation step itself rather than addressing its effects downstream, the invention eliminates the need for additional countermeasures such as enhanced dust collectors or other downstream corrections, thereby preventing pressure loss while avoiding increased device complexity
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 effectively decreases SO3 and NOx concentrations, reducing corrosion and performance degradation, thereby enhancing the efficiency and reliability of discharge gas treatment systems while minimizing the need for additional countermeasures.
Implementation Method 1
NOx is decomposed by use of ammonia (NH3), serving as a reducing agent, in the presence of a nitrogen oxide removal catalyst
Implementation Method 2
NOx reduction for removal thereof
Implementation Method 3
oxidation of SO2 to form sulfur trioxide (SO3)
Implementation Method 4
reduction of SO3 to SO2
Data Source
AI summary
The invention provides a discharge gas treatment catalyst which can effectively decreases NOx and SO3 contained in a discharge gas. The discharge gas treatment catalyst, for removing nitrogen oxide and sulfur trioxide from a discharge gas, includes a carrier which is formed of titania-tungsten oxide and which carries ruthenium, and a titania-tungsten oxide-based NOx removal catalyst serving as a substrate which is coated with the carrier. When a discharge gas to which ammonia has been added and which contains SO3 and NOx is brought into contact with the catalyst, decomposition of ammonia is suppressed by ruthenium, and reduction of SO3 and NOx contained in the discharge gas is promoted, whereby SO3 concentration and NOx concentration can be further decreased.