Urea Ammonium Formate Reducing Agent Preparation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for preparing reducing agent compositions for nitrogen oxide catalytic reduction face challenges such as high material costs, energy-intensive processes, and difficulties in achieving the required purity and homogeneity, especially when using urea and ammonium formate, which are sensitive to crystallization and decomposition.
Innovation Solution
A two-stage or one-stage process is employed where urea is added to an aqueous solution of ammonium formate, prepared in situ from pure starting materials like ammonia and formic acid, eliminating the need for separate crystallization and dehydration stages, and using a tube reactor for efficient mixing and control of solution concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If urea solution is used for selective catalytic reduction, then the process is simple and cost-effective, but the frost resistance is limited to -11°C and the catalyst deactivates faster
Solution Approach 1:
The patent combines urea with ammonium formate to create a composite reducing agent solution. This composite approach leverages the complementary properties of both substances: urea provides cost-effectiveness and ease of handling, while ammonium formate enhances frost resistance and catalyst stability. The synergistic combination resolves the contradiction by integrating the advantages of both components into a single reducing agent formulation.
Solution Approach 2:
The patent modifies the chemical composition parameters of the reducing agent by adjusting the ratio of urea to ammonium formate. By changing these compositional parameters, the solution achieves improved frost resistance (down to -30°C) and enhanced catalyst stability while maintaining reasonable ease of manufacture. The parameter optimization allows balancing multiple competing requirements.
2Temperature
If ammonium formate is added to improve frost resistance, then the freezing point decreases to -30°C, but the process complexity increases and material costs increase
Solution Approach 1:
The patent merges the preparation of ammonium formate with the urea solution formulation process. Instead of separately preparing ammonium formate and then mixing it with urea, the method combines these steps into an integrated process where ammonium formate is prepared in-situ during the same operational sequence. This merging reduces process complexity and eliminates the need for separate preparation equipment.
Solution Approach 2:
The patent performs preliminary preparation of ammonium formate in-situ before final mixing with urea. By preparing ammonium formate advance during the same process sequence rather than requiring separate pre-preparation steps, the method reduces overall process complexity. The in-situ preparation eliminates the need for separate storage and handling of ammonium formate.
3Manufacturing precision
If pure starting materials are used to achieve high purity, then the reducing agent meets stringent purity criteria, but the material costs and energy consumption increase
Solution Approach 1:
The patent uses water as an intermediary medium in the in-situ preparation of ammonium formate. By utilizing water as the solvent and reaction medium, the process achieves high purity without requiring energy-intensive distillation or evaporation steps. Water facilitates the chemical reaction and subsequent mixing with urea while maintaining solution homogeneity and purity, thereby reducing energy consumption compared to alternative purification methods.
4Manufacturing precision
If separate crystallization and dehydration stages are used, then the purity is improved, but the process complexity increases and handling issues arise
Solution Approach 1:
The patent extracts and eliminates the separate crystallization and dehydration stages from the traditional process sequence. By removing these complex and handling-intensive steps, the method achieves the same purity objectives through a simplified in-situ preparation approach. The extraction of problematic process stages directly addresses the handling ease issue while maintaining product quality.
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
This method simplifies the process, reduces costs, and ensures a homogeneous, high-purity reducing agent composition with improved frost resistance and stability, meeting stringent purity criteria while minimizing energy consumption and handling issues related to crystallization.
Implementation Method 1
an aqueous solution of ammonium formate, which is prepared from starting materials other than solid ammonium formate
Implementation Method 2
adding urea to an aqueous solution of ammonium formate
Implementation Method 3
using a tube reactor for efficient mixing and control of solution concentration
Data Source
AI summary
The invention relates to a method for preparing a reducing agent composition, which is used in the selective catalytic reduction of nitrogen oxides and which contains from 20 to 40% by weight of urea, from 20 to 40% by weight of ammonium formate, and water. The composition is prepared by adding urea to the aqueous solution of ammonium formate that is prepared in situ, and by preparing the aqueous solution of ammonium formate using, as starting materials, a source of ammonium, a source of formate, and water.