Electrostatic Precipitators for Urea Plant Gas Cleaning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current systems for cleaning gas streams from urea plant solidification units are inefficient, leading to high energy consumption, frequent maintenance needs, and poor removal of urea powder and ammonia due to the use of scrubbers, which also result in environmental emissions and corrosion issues.
Innovation Solution
The implementation of electrostatic precipitators, both 'dry' and 'wet', to replace traditional scrubbers, utilizing existing substances and conditioning techniques to enhance removal efficiency, reducing energy consumption and maintenance requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If scrubbers are used to remove urea powder and ammonia from the gas stream, then the gas purification function is provided, but the removal efficiency is low and fouling/corrosion problems occur on downstream fans
Solution Approach 1:
The patent replaces the mechanical scrubbing system with an electrostatic precipitation system. Instead of using liquid scrubbers that cause fouling and corrosion, the invention employs electrostatic fields to charge and collect urea particles and ammonia molecules on collector plates, eliminating the harmful wet scrubbing effects while maintaining high removal efficiency
Solution Approach 2:
The patent changes the physical-chemical parameters of the gas stream by introducing electrostatic charging. The gas phase ammonia and urea particles are transformed into charged species through corona discharge, allowing them to be collected on oppositely charged collector plates with high efficiency, fundamentally changing the removal mechanism from mechanical/chemical scrubbing to electrostatic separation
2Reliability
If scrubbers are used to purify the gas stream, then gas cleaning is achieved, but significant energy consumption and costs are incurred for urea recovery from the aqueous solution
Solution Approach 1:
The patent replaces the energy-intensive aqueous scrubbing and evaporation system with an electrostatic precipitation system that operates without liquid absorption media. The electrostatic field directly captures urea particles and ammonia molecules, eliminating the need for large volumes of water and the subsequent energy-consuming evaporation processes required to recover urea from scrubber liquids
Solution Approach 2:
The patent extracts and removes urea particles and ammonia from the gas stream directly through electrostatic collection, bypassing the intermediate step of dissolving them in large volumes of water. The collected materials are deposited on the electrostatic precipitator plates where they can be periodically removed and processed, eliminating the energy-intensive water evaporation step
3Reliability
If scrubbers with demisters are used to separate liquid drops from the gas current, then separation is achieved, but significant consumption of makeup water is required for cleaning the demisters
Solution Approach 1:
The patent replaces the wet scrubber with demisters with a dry electrostatic precipitation system. Since no liquid scrubbing media is used, there are no liquid-saturated demisters requiring water cleaning. The electrostatic precipitator collectors are dry surfaces that can be cleaned mechanically or by vibration, eliminating the continuous makeup water requirement for demister maintenance
Solution Approach 2:
The patent extracts and removes liquid urea droplets from the gas stream through electrostatic collection before they would require demister separation. The electrostatic field charges and collects both liquid droplets and gaseous ammonia on the collector plates, eliminating the need for downstream demisters and their associated water cleaning requirements
4Productivity
If traditional scrubbers are used in high-flow urea plants, then gas treatment is provided, but distribution of the gas stream is poor and efficiency drops due to aerosol formation
Solution Approach 1:
The patent replaces the mechanical scrubbing system with an electrostatic precipitation system that is not limited by gas distribution issues. The electrostatic field acts uniformly across the entire cross-section of the gas stream, effectively treating high-volume flows without the distribution problems that plague traditional scrubbers at high capacities
Solution Approach 2:
The patent changes the removal mechanism from mechanical impingement and liquid absorption to electrostatic charging and collection. This fundamental parameter change allows the system to maintain high removal efficiency across a wide range of gas flow rates, as the electrostatic force acts on individual charged particles regardless of the overall gas velocity or distribution patterns
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 approach significantly improves the removal efficiency of urea powder and ammonia, minimizing environmental emissions and corrosion, while reducing energy costs and maintenance needs, allowing for more compact and cost-effective systems.
Implementation Method 1
a first electrostatic precipitator to charge and collect urea particles
Implementation Method 2
a second electrostatic precipitator to charge and collect ammonia molecules
Data Source
Figure 1
Figure 2
AI summary
A cleaning system (1) for cleaning a gas stream from a solidification unit (2) of a urea plant (3) comprises a first removal device (7) for removing urea powder and a second removal device (8) for removing ammonia, the two removal devices (7, 8) being arranged in series along a gas treatment circuit (13) and connected by a connecting line (16); at least one of the two removal devices (7, 8) is an electrostatic precipitator (11, 12) designed to remove substantially all or at least most of the contaminant treated in the removal device (7, 8), i.e. urea powder or ammonia.