Related Experiment Video
Updated: Jun 22, 2026
11:47
Using 2-Photon Microscopy to Quantify the Effects of Chronic Unilateral Ureteral Obstruction on Glomerular Processes
Published on: March 4, 2022
Effect of oxygenated liquid additives on the urea based SNCR process
M Tayyeb Javed1, W Nimmo, Asif Mahmood
1Department of Chemical and Materials Engineering, Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore Islamabad, Pakistan. m.t.javed@pieas.edu.pk
Journal of Environmental Management
|June 23, 2009
Summary
Oxygenated liquid additives impact nitrogen oxides (NOx) removal via selective non-catalytic reduction (SNCR) with urea. While some additives lower effective temperatures, they often reduce peak NOx reduction efficiency in flue gas treatment.
Area of Science:
- Environmental Chemistry
- Chemical Engineering
- Combustion Science
Background:
- Selective Non-Catalytic Reduction (SNCR) is a key technology for reducing nitrogen oxides (NOx) in flue gases.
- Urea is a common reducing agent in SNCR processes.
- Optimizing SNCR performance requires understanding the influence of various additives.
Purpose of the Study:
- To investigate the effect of oxygenated liquid additives on NOx removal efficiency using urea in the SNCR process.
- To evaluate the impact of hydrogen peroxide (H2O2), ethanol (C2H5OH), ethylene glycol (C2H4(OH)2), and glycerol (C3H5(OH)3) on SNCR performance.
- To determine the influence of these additives on the optimal temperature range for NOx reduction.
Main Methods:
- Experimental investigation using a 150kW pilot-scale reactor with simulated flue gas from methane combustion.
- Controlled introduction of urea as the reducing agent and ammonia doping to achieve target NOx levels (500ppm).
- Systematic addition of H2O2, C2H5OH, C2H4(OH)2, and C3H5(OH)3 to study their effects across a temperature range of 800-1200°C.
Main Results:
- Hydrogen peroxide (H2O2) addition shifted the peak reduction temperature down by 150°C but reduced peak efficiency from 81% to 63%.
- Ethanol (C2H5OH) further decreased peak NOx reduction efficiency to 50% while shifting the optimal temperature down by 180°C.
- Ethylene glycol (C2H4(OH)2) enabled 50% NOx reduction above 940°C.
- Glycerol (C3H5(OH)3) significantly reduced peak efficiency to 40% but allowed reductions at a much lower temperature (800°C), a 330°C shift.
Conclusions:
- Oxygenated liquid additives significantly alter the temperature dependence and efficiency of urea-based SNCR for NOx removal.
- H2O2, ethanol, ethylene glycol, and glycerol offer trade-offs between lower operating temperatures and reduced peak NOx reduction efficiency.
- The choice of additive depends on specific operational requirements and acceptable NOx emission levels in flue gas treatment.
Related Concept Videos
01:23Urea Cycle
The urea cycle describes how liver cells convert ammonia to urea. Ammonia is a toxic waste product of protein catabolism. Land animals must convert ammonia into the less toxic urea which can be safely eliminated by the kidneys through urine. Marine animals excrete ammonia directly, and the surrounding water dilutes the ammonia to safe levels.
02:24Comparative Excretory Systems
Animals have evolved different strategies for excretion, the removal of waste from the body. Most waste must be dissolved in water to be excreted, so an animal’s excretory strategy directly affects its water balance.
02:23RNA Editing
RNA editing is a post-transcriptional modification where a precursor mRNA (pre-mRNA) nucleotide sequence is changed by base insertion, deletion, or modification. The extent of RNA editing varies from a few hundred bases, in mitochondrial DNA of trypanosomes, to a just single base, in nuclear genes of mammals. Even a single base change in the pre-mRNA can convert a codon for one amino acid into the codon for another amino acid or a stop codon. This type of re-coding can significantly affect the...
01:18Bioreactor Controls-II
In aerobic fermentations, oxygen is vital for microbial growth and metabolite production. Since air comprises only about 20% oxygen and the gas is poorly soluble in water—just 9 ppm at 20°C—supplying sufficient oxygen becomes a critical challenge, especially in high-demand processes like yeast growth or citric acid production. Even a fully saturated broth may offer only a few seconds of oxygen availability.To address this, sterile or scrubbed air is introduced into the fermentor via a sparger...
01:20Formation of Dilute Urine
The formation of dilute urine is a critical renal adaptation that maintains fluid balance, particularly during periods of high fluid intake. This process primarily involves the juxtamedullary nephrons. By adjusting the permeability of water and ions in response to physiological conditions, the kidneys can either conserve or excrete water, resulting in concentrated or dilute urine.
Filtrate Osmolarity in the PCT
Initially, as the filtrate passes through the proximal convoluted tubule (PCT), its...
Filtrate Osmolarity in the PCT
Initially, as the filtrate passes through the proximal convoluted tubule (PCT), its...