Plant Tail Gas Research Articles

Evaluation of the inhibiting effect of H2O, O2, and NO on the performance of laboratory and pilot K-ZnxCo3-xO4 catalysts supported on α-Al2O3 for low-temperature N2O decomposition

The K-ZnxCo3-xO4 catalyst supported on α-Al2O3 for N2O decomposition was investigated in terms of its resistance towards typical contaminants (O2, H2O, and NO) present in the nitric acid plant tail gases. The catalyst synthesized in laboratory-scale was thoroughly characterized by means of X-ray μ-tomography, XRF, XRD, and SEM/TEM/EDX. The impact of contaminants such as O2, H2O, and NO on the N2O conversion of the catalyst was examined and quantified by kinetic and thermodynamic modeling. The mechanism of inhibition involving local (active site blocking) and global (modification of the spinel electronic properties by electrophilic NOx adspecies) effects was proposed. The strongest inhibition of NO was associated with its facile reactivity with surface O intermediates produced during N2O decomposition. The resultant NO2 and NO3 surface adducts are stable at the catalyst surface up to 550 °C. For the pilot catalyst, the effect of contamination was the same in nature as for the laboratory sample, however, the observed quantitative differences were associated with the changes in the shape of the spinel nanocrystals constituting the catalyst active phase. The obtained results provide rationales for designing and preparation of the robust deN2O catalyst with enhanced resistivity to poisoning.

Enhancement of microalgal lipid production in municipal wastewater: Fixation of CO2 from the power plant tail gas

Insufficient carbon source is the main limiting factor for microalgae cultivation in wastewater. The use of power plant tail gas to provide carbon source for microalgae could simultaneously reduce CO2 and promote both microalgal growth and lipid production. In this work, the effect of CO2 from the power plant tail gas on Chlorella pyrenoidosa grown in wastewater was primarily studied. The results showed that the dry weight and lipid productivity of C. pyrenoidosa was significantly increased by 84.92 and 74.44% in the presence of power plant tail gas, respectively. Meanwhile, the optimum carbon fixation sequestration of microalgae was 1.121 g/L and the average carbon fixation rate was 0.209 g/(L·d), which was 134.22% and 107.07% higher than the blank group. The effects of various toxic components of power plant tail gas on the growth of microalgae were also investigated. The results showed that the pretreatment process including desulfurization and denitrification of the power plant tail gas is needed before the utilization of CO2.

Catalytic combustion of Claus tail gas: Oxidation of sulfur species and CO using gold supported on lanthanide-modified TiO2

Sulfur recovery processes aimed at the reduction of SO2 emissions can unintentionally contribute to increased greenhouse gas emission through the final incineration stage. In the past two decades, metal oxide supported gold nanoparticles have shown their catalytic activity for low-temperature CO oxidation, and they could be candidates for Claus plant tail gas incineration catalysts. This study was aimed at finding a durable catalyst and reasonable conditions for the Claus tail gas incineration process, which involves relatively high temperatures (573–623 K), up to 1% sulfur species, and a high concentration of water vapor (16.7%). Lanthanide oxides (i.e., La2O3, Eu2O3 or Er2O3) were deposited on the surface of titania xerogel, followed by impregnation with gold and calcination at 673 K. Results showed that the Eu2O3/TiO2 supported gold was the most active for CO oxidation, because the electron transfer from the bulk TiO2 to Au nanoparticles and higher sulfate tolerance.

Method for analysis of ClO2 and Cl2 air emissions from pulp mill

Abstract Chlorine dioxide is commonly used as a bleaching agent in kraft pulp mills. Scrubbers are required to remove any remaining ClO2 from the plant tail gases. To control the air emissions of chlorine compounds, chlorine dioxide and chlorine contents must be monitored to ensure that the strict regulatory standards are met. However, the currently used analytical method is not suitable for detection of low concentrations of chlorine and chlorine dioxide. A new method for measuring chlorine dioxide and chlorine emissions was developed, which ensures compliance with the stringent requirements imposed by the authorities. The two species could be measured separately with a limit of quantification of 3 ppm. The method was robust and easy to use in the pulp mill environment and it was validated both in the laboratory and the field. The specificity of the method was demonstrated, Cl2 analysis was not sensitive to the presence of ClO2 and vice versa. The uncertainty (±2×RSD) of the analytical method in the field was estimated from duplicate measurements performed in the range of 3–500 ppm for ClO2 and 3–300 ppm for Cl2, and was found to be ±20 % and ±10 %, respectively. Possible interferences in the analytical method are also discussed.

Direct Decomposition of N2O Emitted from Nitric Acid Plant Tail Gases Using Noble Metal Supported Mordenite-Zeolite Catalysts∗

Abstract Mordenite based catalysts for direct decomposition of N2O have been successfully prepared and their direct decomposition performance characterized at the operating temperature of 300–400 °C commonly encountered in the nitric acid plants tail gases. The catalyst was prepared in 2 steps: 1. Precursor wet ion exchange, 2. Precursor impregnation. In addition to the previous contribution, it is shown here that the bimetallic Rh-, Pd-, Ir-Fe-MOR catalysts thus prepared exhibited an excellent N2O decomposition performance: total conversion efficiency of Rh-Fe-MOR catalyst has been achieved at 400 °C and between 7500 h−1 and 10 000 h−1 space velocity.

Recovery of Hydrogen from Ammonia Plant Tail Gas by Absorption-Hydration Hybrid Method

In this work, the absorption-hydration hybrid method was used to recover (hydrogen + nitrogen) from (hydrogen + nitrogen + methane + argon) tail gas mixtures of synthetic ammonia plant through hydrate formation/dissociation. A high-pressure reactor with magnetic stirrer was used to study the separation efficiency. The influences of the concentration of anti-agglomerant, temperature, pressure, initial gas-liquid volume ratio, and oil-water volume ratio on the separation efficiency were systematically investigated in the presence of tetrahydrofuran (THF). Anti-agglomerant was used to disperse hydrate particles into the condensate phase for water-in-oil emulsion system. Since nitrogen is the material for ammonia production, the objective production in our separation process is (hydrogen + nitrogen). Our experimental results show that by adopting appropriate operating conditions, high concentration of (hydrogen + nitrogen) can be obtained using the proposed technology based on forming hydrate.

Laboratory and pilot scale synthesis, characterization and reactivity of multicomponent cobalt spinel catalyst for low temperature removal of N 2O from nitric acid plant tail gases

Synthesis of a multicomponent (K, Zn-doped) cobalt spinel deN 2O catalyst developed in a laboratory was extended to a pilot scale. The optimal composition and morphology of the prototype catalyst elucidated in the laboratory conditions were successfully reproduced upon large scale synthesis and shaping. Tuning of the catalyst properties was guided by in situ work function measurements in conjunction with the TPRS tests of N 2O decomposition including the effect of water and oxygen inhibitors. In the pilot tests the engineered catalyst exhibited high performance (conversion >95% below 350 °C) in N 2O removal from the real tail gases of the nitric plant for at least 20 days.

Catalytic performance of Fe-, Pd-, and Pd–Fe- mordenites in simulated hydrocarbon-selective catalytic reduction of N2O by methane in a model flue-gas from nitric acid plants

AbstractThis paper reports on the individual activity and selectivity of Fe-, Pd- and Pd – Fe-mordenite catalysts prepared by wet Fe-ion exchange and Pd-ion impregnation for N2O reduction using simulated hydrocarbon-selective catalytic reduction operation conditions of nitric acid plants. Laboratory-scale data on the activity, selectivity and characterization of Fe-, Pd-, and Pd – Fe-mordenite catalysts for conversion of N2O have been obtained under the simulated hydrocarbon-selective catalytic reduction operating condition in the temperature range of 325 – 400 °C encountered in nitric acid plant tail gases. More specifically, Pd-, Fe- and Pd – Fe-mordenite catalysts with Si/Al ratios of 10.25 – 10.65 were prepared. Wet ion-exchange methodology was used to prepare Fe-mordenite catalyst, whilst Pd-ion impregnation was used to prepare Pd-, and Pd – Fe-mordenite catalysts. Catalytic activities could not be consistently correlated with and explained by X-ray absorption near edge spectroscopy spectra. Further analysis by temperature-programmed desorption of ammonia was performed to explain higher catalytic activity of Pd – Fe-mordenite compared to Fe-, and Pd-mordenites. Higher catalytic activity of Pd – Fe-mordenite is most probably attributable to the presence of strong Lewis type acid centers as manifested by a TPD spectrum peak at about 300 °C.

Fabrication of CdS/TiO 2 nano-bulk composite photocatalysts for hydrogen production from aqueous H 2S solution under visible light

CdS/TiO 2 nano-bulk composite (NBC) photocatalyst of a new configuration consisting of bulky CdS with high crystallinity decorated with nanosized TiO 2 particles exhibited an unprecedented high rate of hydrogen production under visible light irradiation ( λ ⩾ 420 nm) from water containing sulfide and sulfite ions as hole scavengers. The fabrication method of the composite photocatalysts was critical for their performance. It was demonstrated that this active composite photocatalyst could be applied for practical processes of simultaneous hydrogen production and H 2S removal in the treatment of Claus plant tail gas streams or vents of hydrodesulfurization plants.

4425317 Recycle of hydrogenated sulfur plant tail gas to sour gas scrubbing system

4425317 Recycle of hydrogenated sulfur plant tail gas to sour gas scrubbing system

Application of the Lime/Limestone Flue Gas Desulfurization Process to Smelter Gases

In this presentation, adaptation of the lime/limestone process for flue gas desulfurization (FGD) is discussed and how this process can be adapted to applications in the nonferrous smelting industry such as fugitive gases, copper reverberatory furnace gases, lead sintering gases, molybdenum roasting plant tail gases, and other weak SO2 smelter gases. Different methods for particulate removal are also discussed with emphasis on how the particulate removal process can be integrated with the desulfurization process.

The chemistry of the Beavon sulfur removal process

The Beavon Sulfur Removal Process (BSRP) removes essentially all of the sulfur compounds from Claus plant tail gases. The sulfur containing compounds, such as hydrogen sulfide, sulfur dioxide, carbonyl sulfide and carbon disulfide, are converted to sulfur in over 99.9% efficiency. The BSRP consists of two stages. In the first stage the various sulfur compounds are either hydrogenated or hydrolyzed to give hydrogen sulfide while in the second stage the hydrogen sulfide is oxidized using the Stretford process to give elemental sulfur of good quality. The process is a commercial success with 29 plants operating or under construction in the United States and 4 in Japan. This process can also be utilized in Synthetic Natural Gas plants, natural gas processing, and other similar applications.

ChemInform Abstract: THE PURASIV S PROCESS FOR REMOVING ACID PLANT TAIL GAS

Chemischer InformationsdienstVolume 5, Issue 44 Other Subjects ChemInform Abstract: THE PURASIV S PROCESS FOR REMOVING ACID PLANT TAIL GAS J. J. COLLINS, J. J. COLLINSSearch for more papers by this authorL. L. FORNOFF, L. L. FORNOFFSearch for more papers by this authorK. D. MANCHANDA, K. D. MANCHANDASearch for more papers by this authorW. C. MILLER, W. C. MILLERSearch for more papers by this authorD. C. LOVELL, D. C. LOVELLSearch for more papers by this author J. J. COLLINS, J. J. COLLINSSearch for more papers by this authorL. L. FORNOFF, L. L. FORNOFFSearch for more papers by this authorK. D. MANCHANDA, K. D. MANCHANDASearch for more papers by this authorW. C. MILLER, W. C. MILLERSearch for more papers by this authorD. C. LOVELL, D. C. LOVELLSearch for more papers by this author First published: November 5, 1974 https://doi.org/10.1002/chin.197444430Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume5, Issue44November 5, 1974 RelatedInformation

Removal and Recovery of NOx from Nitric Acid Plant Tail Gas by Adsorption on Molecular Sieves

Removal and Recovery of NO_x from Nitric Acid Plant Tail Gas by Adsorption on Molecular Sieves

The Catalytic Treatment of Nitric Acid Plant Tail Gas

The Catalytic Treatment of Nitric Acid Plant Tail Gas