Fig 4 - uploaded by Deshai Botheju
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NOx and CO concentration variation during one full scale trial conducted with MEA injection at a rate of 550 l/hr (Injection position: 5th floor level of the precalciner).
Source publication
Amine reclaimer wastes (ARW) generated in carbon capture and sequestration (CCS) is categorized as a hazardous waste which needs proper disposal. The proposal described in this paper can bring about a multi-effective solution to the problem of CCS waste handling. Both the pilot scale and the full scale experimental trials carried out in this study...
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Context 1
... full scale demonstration tests conducted using aqueous NH 3 and MEA corroborated the observations made in pilot scale experiments. Fig. 4 illustrates NO x reduction vs. time evolution data from one experimental run conducted with MEA injection at a rate of 550 l/hr corresponding to a TN/NO ratio of 1. NO x reduction up to about 30% is observed at this condition. It took a certain time before the NO x level reached its minimum level, apparently due to the time lapse ...
Context 2
... up to about 30% is observed at this condition. It took a certain time before the NO x level reached its minimum level, apparently due to the time lapse needed for the system to reach uniform mixing of chemical throughout the reaction volume. Once the chemical injection had stopped, the NO x level gradually rose to its pre-injection level. Fig. 4 also indicates CO emission during the injection period. Corresponding to the maximum NO x reduction, the CO level shows a peak increase. This behavior can mainly be due to the fast consumption of OH radicals by amine compounds as shown in Eq. ...
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Executive Summary Coal-fired utility boilers generate over 50 percent of the electricity in the United States. Concerns about the effect of anthropogenic emissions of carbon dioxide (CO 2) on global climate will undoubtedly result in regulations restricting CO 2 emissions from existing and newly built emitting sources. While the oxy-fuel, IGCC, and...
Citations
... However, the potential of waste amines to reduce NOx is lower than that of NH 3 [166,167]. Several authors have investigated the use of waste amine for the reduction of NOx [168][169][170][171]. Stanciulescu et al. [168] studied the reductant performance of methylamine, ethylamine, propylamine, and butylamine. ...
... They reported inferior efficiency when compared with the industrially utilized urea solution AdBlue (32.5 wt % urea). Botheju and their coworkers [170,171] studied the use of waste amine as a reductant for the selective non-catalytic reduction of NO x in flue gases and reported approximately 20% efficiency, with much higher efficiencies under different parametric conditions. However, reusing waste amines upstream of the PCC plant could engender alterations in the concentration of different metals and compounds in the incoming flue gas [167]. ...
... When TN/NO ratios are less than 1.6, the NO x reduction potential of reclaimer-generated wastewater is equivalent to that of MEA but lower than that of NH 3 (Botheju et al., 2012;Locci et al., 2018). Pilotscale experiments confirmed that the NO x reduction efficiencies of three reagents (i.e., NH 3 , MEA, and reclaimer-generated wastewater) are approximately 60%, 35%, and 28%, respectively (Botheju et al., 2013). The NOx reduction potentials of MEA and reclaimergenerated wastewater are clearly not as superior as that of aqueous NH 3 . ...
... The NOx reduction potentials of MEA and reclaimergenerated wastewater are clearly not as superior as that of aqueous NH 3 . This can be understood based on the relatively straightforward SNCR chemistry of NH 3 (e.g., Equations (4.1) and (4.2)) (Botheju et al., 2013). The concentration of ammonia in the flue gas discharged from the absorber is 2e5 ppmv, and its concentration in the reclaimer-generated wastewater is significantly low (IEAGHG, 2014). ...
... In Europe for instance, amines cannot be disposed in landfills as their biological degradation is not sustainable. An acceptable mean for amine reclaimer waste (ARW) valorisation is to employ them as a reducing agent in incinerators [82,83], as they can be thermally destructed, without further environmental issues. Although their NO x reduction potential is inferior to the one of aqueous solutions of NH 3 or water, they still represent an interesting topic to explore because of the costs induced by their disposal. ...
... Further interest arises in the frame of carbon capture technologies, where amines are employed to wash out CO 2 from the flue gas after combustion. NH 3 , monoethanolamine (MEA) and amines were used by Botheju et al. [83] as a reducing agent in both a cement kiln system and a pilot system. In this pilot, the process temperature varied between 700 and 1150 • C. It was found that amines and MEA also have an optimal working temperature interval, with a maximum reduction efficiency reached for a temperature level of about 950 • C. The maximum reduction efficiencies were 60%, 35% and 20% for NH 3 , MEA and amine, respectively. ...
The selective non-catalytic reduction (SNCR) process used to transform nitrogen monoxide molecules into environmentally friendly gases is reviewed with its numerical modeling. The fundamentals of SNCR in terms of chemistry and flow physics are first discussed, to then examine how they impact on the design and optimization of furnaces and incinerators relying on this technology. The various options in operation today are presented for coal-fired or waste-to-energy power plants, biomass and CO boilers. In complement, specific applications using additive components are discussed along with the amine reclaimer waste approach. The methodology and the challenges of computational fluid dynamics applied to SNCR systems are reviewed, before discussing emerging simulation techniques, as large eddy simulation (LES) of such complex systems. The modeling of the multicomponent evaporation of the liquid reagent injected for transforming NOx, as urea, and the modeling of the chemistry in the gaseous phase, are addressed for the numerical simulation of SNCR. Finally, reduced-order modeling of SNCR is discussed and perspectives are drawn for the control, in situ, of SNCR systems.
... NOx originates from diverse combustion mechanisms [5][6][7][8][9]. Without flue-gas cleaning, the MSW that is incinerated may release more than 1 kg of NOx/ton and will significantly contribute to the overall environmental impact of the incineration plant [10][11][12]. In general, a flue-gas cleaning system is employed selective non-cat-alytic reduction (SNCR) brought about by adding ammonia water for NOx reduction of the flue [6,7]. ...
This study investigates the possibility of applying food waste leachate to a municipal solid waste incinerator in order to effectively dispose of the material and to reduce the environmental impact. The spray positions and the quantity of the food waste leachate in municipal solid waste incinerator were adjusted to examine the stability of the process and the environmental effect. The rear of the first combustion chamber was found to be the desirable location for an environmental perspective in this study. At a food waste leachate injection rate of 2 m3/h, the concentration of the emitted NOx decreased from 130 ppm to 40 ppm. The consumption of ammonia water was reduced by about 36% after adding the food waste leachate. The inclusion of the food waste leachate to the municipal incinerator also increased the amount of steam that was produced. The results of this research indicated that a positive outcome can be expected in terms of diversifying the treatment options for food waste leachate. The results also provide guidance for institutional framework to manage the incineration of the food waste leachate.
Incineration is the most effective method for reducing the increasing waste volume. However, as the pollutants generated during incineration may cause secondary pollution, blocking them in advance is necessary. During incineration, prevention facilities are operated to reduce the amount of pollutants. Conventional selective non-catalytic reduction (SNCR) reduces nitrogen oxides (NO x ) by injecting ammonia and urea as reducing agents. In this study, the NO x reduction effect on food wastewater (FW) was examined. In addition, the removal efficiency was compared at different concentrations of urea mixed with FW. When different concentrations of urea were injected in SNCR facilities A, B and C, NO x removal efficiencies of up to 75% were observed; with FW injection only, removal efficiency was 56%; and when both urea and FW were injected, removal efficiency was up to 79%. Although FW showed a lower NO x removal efficiency than urea, injecting both increased the efficiency. In addition, when air pollutant emissions and the incinerator temperature were analysed, we found that they could be managed without exceeding the allowed limits. However, for the injection and incineration of reducing agents, the characteristics of the incineration facility and reducing agents must be considered.
A study was performed to investigate monomethylamine (MMA) as an alternative or supplementary reagent for selective non-catalytic reduction (SNCR) of nitrogen oxides (NOx) for power plants especially the coal-fired type. A detailed chemical kinetics mechanism for MMA, related to the SNCR NOx reduction process, was modeled using a simplified plug flow reactor (PFR) approach using the CHEMKIN software. Model validation results were in line with reported experimental results. A model sensitivity analysis showed that the normalized MMA/NO stoichiometric ratio (NSR) and the initial NOx concentration are the most critical parameters that significantly affect MMA-based process performance. Additionally, a reduced reaction mechanism and its mechanism tree for this particular process are proposed, consisting of only 18 reactions and 21 species. Simulation comparisons with three other reagents (ammonia, urea, and cyanuric acid), under similar process conditions, indicate that MMA-based SNCR NOx reduction process has a superior performance at much lower temperatures (under 800 K) than conventional SNCR processes, with the added benefit that it does not suffer from ammonia slip problems. The MMA-based SNCR NOx removal system could be applied in cascade mode with other post-combustion NOx removal approaches to extend NOx control to lower temperatures and eliminate the temperature window limitation and potential ammonia slip of conventional SNCR systems. The cascade design is a perfect solution for coal power plants especially at partial load modes of operation which provides more flexibility in performance for such plants. The results of the simulations in this study show that the potential of MMA for SNCR NOx reduction systems at full-scale power plants has significant merit.
Amine-based carbon dioxide capture is the most mature technology for reducing flue gas CO2 emissions. It has been postulated and observed during commercialisation of this technology that significant quantities of waste amines are produced. Further industrial implementation of this technology requires adequate disposal or valorisation options for this waste. This review presents an analysis of seven biological and chemical technologies for waste amine amelioration or valorisation. Of these, the biological treatments are identified as being more mature for industrial application with the capacity for marketable product generation. Slow speed is the main drawback of the biological processes but this does not hinder their commercial viability. Using waste amine for NOx reduction in power stations is a secondary option, where it seems probable that the amount of waste amine generated in the CO2 capture plant is sufficient to fulfil the DeNOx requirements of the flue gas. This route, however, requires investigation into the impact of waste amine impurities on the power station and the CO2 capture plant operations.
