Copper Catalyst NOx Removal for Polymerization Safety
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Solution Overview
Problem
The presence of NOx in polymerization processes is detrimental to catalysts, leading to reduced polymerization rates and lower polymer quality, as well as posing safety risks due to the formation of NOx gums.
Innovation Solution
A process involving the selective removal of NOx from gaseous streams using a catalyst consisting of metallic copper on a support, in the presence of hydrogen, converting NOx to N2 and H2O, thereby reducing NOx levels and improving process safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If NOx is present in the gaseous stream, then polymerization can proceed, but catalyst activity is reduced and polymer quality deteriorates
Solution Approach 1:
The patent extracts and removes NOx from the gaseous stream before it reaches the polymerization catalyst. A catalytic converter with copper-based catalyst is used to convert NOx into N2 and H2O, effectively separating the harmful contaminant from the process stream. This extraction prevents NOx from poisoning the catalyst and maintains both productivity and reliability.
Solution Approach 2:
The patent introduces an intermediary substance - a copper-based catalytic converter - that mediates between the NOx-containing gaseous stream and the polymerization catalyst. This intermediary converts the harmful NOx into harmless N2 and H2O through catalytic action, protecting the main catalyst from poisoning while allowing the polymerization process to continue uninterrupted.
2Productivity
If NOx is present in the gaseous stream, then polymerization can proceed, but polymer yield is reduced and grade deteriorates
Solution Approach 1:
The patent extracts NOx from the gaseous stream upstream of the polymerization reactor. By removing this harmful contaminant through catalytic conversion in a separate unit, the system maintains both high polymer yield and consistent polymer grade, preventing NOx-induced reductions in productivity and quality.
3Productivity
If NOx is present in the gaseous stream, then polymerization can proceed, but safety risks increase due to NOx gum formation
Solution Approach 1:
The patent extracts and removes NOx from the gaseous stream before it can condense and form harmful gums in downstream equipment. By eliminating the root cause (NOx) upstream through catalytic conversion, the system prevents safety hazards associated with NOx gum formation in cryogenic distillation units, heat exchangers, and piping.
Solution Approach 2:
The patent applies preliminary anti-action by preventing NOx from causing harm before it can manifest as safety risks. The catalytic converter proactively converts NOx into harmless N2 and H2O upstream, preventing the subsequent formation of explosive NOx gums in colder equipment and eliminating the need for complex downstream protection systems.
4Object-affected harmful factors
If a catalyst is used to remove NOx, then NOx levels are reduced, but process complexity increases
Solution Approach 1:
The patent employs a relatively simple and cost-effective copper-based catalytic converter that can be easily installed and maintained. The catalyst operates at moderate temperatures and requires only periodic regeneration, avoiding the need for complex high-temperature furnaces or multiple treatment stages. This straightforward approach reduces process complexity while effectively lowering NOx levels.
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 process effectively reduces NOx levels in gaseous streams to below 2 ppmv, preventing catalyst poisoning and improving polymer quality, while also enhancing process safety by minimizing the risk of NOx gum formation and explosions.
Implementation Method 1
The processes involve contacting the gaseous stream containing NOx with a catalyst in the presence of H2. The NOx is converted to N2 and H2O. The catalyst consists essentially of metallic copper on a support.
Implementation Method 2
Prior to beginning the process, copper oxide is reduced to the copper zero state by reduction, typically using hydrogen. In this reaction, metallic copper acts as a catalyst and does not change its oxidation state.
Data Source
AI summary
Processes for selectively removing NOx from various gaseous streams are described. The gaseous streams, include, but are not limited to, hydrocarbon process streams, ammonia combustion gas streams, flue gas streams, cement kiln gas streams, and the like. The processes involve contacting the gaseous stream containing NOx with a catalyst in the presence of H2. The NOx is converted to N2 and H2O. The purified gaseous stream has less NOx less than the level of NOx in the gaseous stream. The catalyst consists essentially of metallic copper on a support with optionally Cu2O, CuO, ZrO2, ZnO, TiO, CeO2, NiO, or combinations thereof.