Removal Of SOx Research Articles

Simultaneous DeNo<SUB>x</SUB> and DeSO<SUB>x</SUB> Technology Using Non-Equilibrium Plasma and Chemical Hybrid Process

A series of experiments were carried out to evaluate the simultaneous NOx and SOx removal using the plasma-chemical hybrid process and to quantify all the reaction byproducts such as N2O and CO. The oxidation from NO to NO2 without decreasing NOx concentration and with least power consumption is the key for obtaining the optimum reactor operating condition. The produced NO2 was totally converted to N2 and Na2SO4 with Na2SO3 or Na2S by the chemical reactor, while NaOH was used to neutralize H2SO3 and H2SO4 in the solution. The final products is water soluble and nontoxic Na2SO4. The NO2 reduction was more effective for Na2S than Na2SO3 but 2 ppm of H2S was produced. The hybrid process showed nearly 100% NOx and SOx simultaneous removal with less than 11 ppm of N2O and CO, and the power consumption using the pulse plasma reactor was less than 1/4 using the packed-bed plasma reactor.

Combustion and carbonisation exhaust utilisation in electric discharge and its relation to prebiotic chemistry

The municipal waste carbonisation inside a high temperature combustion chamber using direct heating by exhaust gas flow in an oxygen free atmosphere is an interesting alternative in the waste management scenario. The process has a lot of similarities with biomass pyrolysis. During carbonisation inside an oven at lower temperatures (∼350°C) the main process is cracking, producing liquid hydrocarbons as levoglucosane and similar tar compounds, then at higher temperatures (∼650°C) hydrogen is formed, while at very high temperatures (∼950°C) carbon char/active carbon is formed instead of ash. The heat from the process can be recuperated.The method for flue gas cleaning with possible application to combustion and carbonisation process uses non-thermal plasma based pilot system for 50–250m3/h of gas flow. The applied method very efficiently cleaned the exhaust gas from a variety of non-wanted compounds, utilising whole combustion exhaust. CO2 removal efficiency was as high as 40–99%. The process is connected with nitrogen fixation, removal of NOx, VOC, PAH, SH and SOx, PCDD, PCDF and other is done with high efficiency and without wastewater production. The final solid amino acids condensation product (proteinoid) made in electric discharge seems to be convenient as a nitrogen containing fertiliser.

Simultaneous Catalytic Removal of NOx, SOx, and CO from FCC Regenerator

Simultaneous catalytic removal of NOx, SOx, and CO under simulated FCC regenerator conditions was investigated over mixed oxide catalysts CuMgAlO (Cu-cat), CeMgAlO (Ce-cat), and CuCeMgAlO (CuCe-cat), which were prepared by coprecipitation and characterized by XRD, XPS, and N2 adsorption−desorption. At low temperatures (<340 °C), the presence of O2 or H2O enhanced the activity of CuCe-cat for NO and CO conversion but significantly suppressed the activity of Cu-cat and Ce-cat. At high temperature (720 °C), the presence of O2 or H2O had no adverse effect on the NO and CO conversions over these catalysts. However, the presence of SO2 in the feed deactivated Cu-cat and Ce-cat drastically while no deactivation of CuCe-cat was observed. The enhanced performance of CuCe-cat can be explained by a synergistic effect between copper and cerium ions, which results in the formation of large amounts of Cu+ ions and oxygen vacancies. Thermogravimetric studies show that this catalyst exhibits excellent performance for SOx adsorption in the SO2 + O2 system and can effectively release the adsorbed SOx in H2 + Ar atmosphere.

Budget and export of anthropogenic SOx from East Asia during continental outflow conditions

We examine the budget and export of anthropogenic SOx (SO2 and sulfate aerosol) emitted from East Asia during the late winter/early spring when continental outflow conditions dominate. Our study is based on simulations using a modified version of the China‐MAP coupled regional climate/chemical transport model of Qian and Giorgi [1999]. The modification involves the addition of algorithms to treat the vertical transport and removal of SOx by convective clouds. Model‐calculated anthropogenic SO2 concentrations peaked at values greater than 20 ppbv at the surface in the urban source regions of China and Korea, but averaged only about 5 pbbv in the rural areas. Midtropospheric SO2 concentrations were more than an order of magnitude less, with peak values of around 0.1–0.15 ppbv overlying the urban source regions. The model‐calculated sulfate aerosol distribution is more disperse, with peak surface concentrations of 5–10 ppbv in urban source regions, and concentrations of about 3 ppbv or less in rural areas and 1 ppbv or less in the midtroposphere. The model‐calculated SOx concentrations are generally within a factor of 2 of the relevant observed concentrations at nonurban sites. The calculations indicate that during the late winter/early spring period, about 50% of the anthropogenic SOx emitted over East Asia is removed from the continental source regions. Roughly 30% is wet and dry deposited onto the neighboring oceans, and the remaining 20% is exported out of the model domain. The vast majority of the exported SOx is in the form of sulfate aerosol and is transported into the midtroposphere overlying the North Pacific Ocean. The rate of SOx export, about 0.2 Tg S per month, is significant when compared to natural S sources to the North Pacific Ocean, suggesting that the export of anthropogenic SOx from East Asia is perturbing sulfate aerosol concentrations over the North Pacific Ocean during the late winter and early spring. On an intraregional basis we find that China is the largest contributor to the emission and export of SOx from East Asia. However, all the nations/continental subregions of East Asia appear to be net exporters of SOx, even those downwind of China.

海水の電解水による舶用排煙ＳＯｘ，ＮＯｘ，ＣＯｘとＰＭの処理システムの開発

In marine air pollution control, only SCR (Selective Catalytic Reduction) is estimated at a variable method to control NOx, but on the other hand, seawater scrubber applying the basic characteristic that is naturally alkaline (pH typically around 8.1) is viewed as an economical SOx removal system at present. Especially, seawater scrubber would not be necessary to follow any of the various land based flue gas desulfurization methods, i.e. wet, dry or alkali scrubbing. However, these methods are not readily adaptable to marine conditions due to the quantities of consumables required, i.e. lime or limestone, the means of operation and the commercial availability.This research is undertaken to develop a new method as the main target of eliminating all exhaust emissions, particularly onboard, because the vessel can easily use seawater and be apt to apply a wet scrubber system. First, with using only seawater, the SOx are absorbed by relatively high solubility compared to other components of exhaust pollutants, and PM (Particulate Matter) is removed through direct contact with sprayed seawater droplets. Besides, the electrolyzed alkaline seawater by electrolysis, which contains mainly NaOH together with alkali metal ions (i.e. Na+, K+, Mg2+, Ca2+), is used as the absorption medium of NOx and CO2. Especially, to increase NOx absorption rate into the alkaline seawater, nitric monoxide (NO) is adequately oxidized to nitric dioxide (NO2) in the acidic seawater, which means both volume fractions are adjusted to identical proportion. The results found that the SOx removal could be achieved nearly perfectly and also led to a sufficient reduction of PM without regard to the pH values of reaction seawater. However, it may be also necessary to do a trial for NOx and CO2absorption with using the electrolyzed seawater.

623 プラズマ・ケミカルプロセスを併用したNOxおよびSOxの同時除去(GS-6・9 強制対流熱伝達)

623 プラズマ・ケミカルプロセスを併用したNOxおよびSOxの同時除去(GS-6・9 強制対流熱伝達)

Combined DeSOx/DeNOx Reactions on a Natural Manganese Ore in a Fluidized Bed Reactor.

Simultaneous removal of SO2 and NOx from simulated gas was investigated using a continuously operating fluidized bed reactor with variables of gas velocity, sorbent/catalyst feeding rate, aspect ratio (L/D), temperature, sorbent/catalyst size. NMO (natural manganese ore) was used as a sorbent and catalyst of size from 0.715 mm to 0.194 mm in diameter. Particle size, aspect ratio, and sorbent feeding rate did not affect the reduction of NOx with ammonia, and NOx removal efficiency was about 94% at 350°C, gas velocity of 0.204 m/sec, L/D=1.0. SOx removal efficiency was affected by temperature, gas velocity, sorbent/catalyst feeding rate, aspect ratio and sorbent/catalyst size and it was about 92% at 450°C, gas velocity of 0.204 m/sec, sorbent/catalyst feeding rate of 8.54 g/min, L/D=1.0.

00/02288 Investigation of desulfurization and sulfur analysis method in hydropyrolysis of coal

Calcium magnesium acetate (CMA) shows potential as a reductant for simultaneous NOx and SOx removal from coal-fired combustion plant. The performance of urea co-injection with CMA on NO reduction in an ‘advanced reburn’ (AR) configuration has been investigated with a view to optimization of the process in a pulverized coal-fired furnace operating at 80 kW. The impact on SO2 reduction has also been investigated. Urea/CMA solution was sprayed into the reburn zone of the furnace using twin-fluid atomizers over a range of reductant/NO stoichiometric ratios (NSR). The influence on NO reductions of primary zone stoichiometry (λ1) was investigated for a range of CMA reburn feed rates (Rff) and reburn zone stoichiometry (λ2). In addition, the effect of temperature on the SNCR performance of urea was investigated. Optimum process conditions were categorized either by maximizing NO and SO2 reductions (Modes A and B, respectively) or maximizing reductant utilization efficiencies (Modes C and D). NO control was best performed at λ1=1.05, but SO2 reductions were greatest at more fuel-lean primary zone conditions (λ1=1.15). Highest NO reductions of 85% under AR-rich conditions were achieved under Mode A, but were only slightly higher compared with reductions of 79% under Mode B, where SO2 reductions were optimized at 85%. N-utilization was also at an acceptable level of 25% compared to the maximum utilization efficiency which was obtained at NSR=1.5 of 30% for the same conditions of stoichiometry operating in Mode C. Operation at this lower level of reburn (9.6%) could significantly reduce the consumption of CMA with some impact on NO reduction (73%). SO2 removal performance would be compromised severely with reductions lowered from 75% at Mode A to 35% at Mode C. Optimizing Ca utilization (Mode D) resulted in poor NO and SO2 reductions, at 61 and 22%, respectively, and can be discounted as a viable option. The technique offers flexibility of operation depending on the emission control requirements.

103 非平衡プラズマを用いたNOxとSOxの同時除去(GS-9 環境工学)

103 非平衡プラズマを用いたNOxとSOxの同時除去(GS-9 環境工学)

Incinerator Flue Gas Cleaning Using Wet-Type Electrostatic Precipitator.

An experimental approach has been adopted to remove dioxins and other pollutants from incinerator flue gas in a pilot-scale experimental system. The main objective of this study is to investigate the combined system for simultaneous removal of gaseous pollutants and dusts. The combined gas cleaning system consists of a radiator, a scrubber and a wet-type electrostatic precipitator (ESP). Dioxins can be decomposed effectively using after-burners downstream of the incinerator by maintaining the gas temperature around 850 ± 20°C. Fractional removal rates for various kinds of dioxins (PCDDs + PCDFs) were measured in this study. When the combined system is used, dioxin removal rates of 90–92% are achieved over a wide range of initial concentrations of dioxins. The combined system is also found to be effective in the removal of NOx, SOx, HCl, and dust.

Removal of SOx and NOx over activated carbon fibers

The recent development of de-SOx and de-NOx using activated carbon fibers (ACF) in Japan is introduced in this review comparing it with the conventional commercialized system. Pitch-based ACFs showed higher de-SOx activity than other ACFs from different precursors. De-SOx activity can be further modified by the heat-treatment, continuous and complete removal of SOx. ACF is also effective for removing NOx in the presence of NH4. The mechanisms of de-SOx and de-NOx on the surface of ACFs are proposed and discussed. Based on fundamental research results de-SOx, de-NOx and their combined processes are designed and proposed.

Electrochemical membrane flue‐gas desulfurization: K2SO4/V2O5 electrolyte

AbstractThe viability of a new electrolyte was demonstrated in the bench‐scale electrochemical removal of SOx from flue‐gas streams at high temperatures. At current densities up to 20 A/m2, approximately 99% current efficiciency was achieved when removing 90% of inlet SOx at 480°C. As current densities increased to 100 A/m2, current efficiencies were 64% at 480°C and 73% at 520°C. While species present in this K2SO4/V2O5 molten salt are not well understood, a simple mechanism was used to develop a model to describe the observed removal results. This model was then used to predict preliminary economic viability of this system based on known electrochemical technology.

Characterization of the Effects of Vanadium Traps in Cracking Catalysts by Imaging Secondary Ion Mass Spectrometry and Microactivity Test

AbstractThe vanadium trapping effect of Mg and La containing additives in cracking catalyst contaminated with 2300 ppm Ni and 4700 ppm V has been analyzed by microactivity test (MAT) and imaging secondary ion mass spectrometry (SIMS). The results of SIMS imaging are consistent with cracking activity data and show that the La/spinel is a superior vanadium trap for the fluid catalytic cracking of hydrocarbons (FCC) operation. La/spinel serves as a dual function additive for both vanadium trap and SOx removal. The optimum amount of La/spinel added to the cracking catalyst is about 15% by weight. This results in an increased catalytic activity, an increase in gasoline yield, and a decrease in coke and gas factors. The MgAl2O4 phase of Mg/Al2O3 additive is found capable of trapping vanadium while its MgO of Mg/Al2O3 phase can migrate to zeolite particles (the active component of the FCC catalyst) that, in turn, causes a decline in the activity of that catalyst.

97/04157 Complex approach to the issue of decreasing occupational diseases during stripping of thin and extremely thin layers of coal at Eastern Donbass mines

Despite the recent remarkable advances in the development of Cu-zeolite materials for selective catalytic reduction (SCR) of NOx with NH3, their performance is not immune to the poisoning by sulfur oxide species SO2 and SO3, commonly referred as SOx. Periodic removal of SOx, i.e. deSOx, is needed to maintain high NOx conversion efficiency of these catalysts even when ultra-low sulfur diesel (ULSD) fuel is used. Such deSOx events require high temperatures, typically in excess of 550 °C, which can be detrimental to the durability of the SCR catalysts and other aftertreatment components, and may also result in a fuel penalty. In this work, a recently discovered method, herein referred to as chemical deSOx, was found to be effective for removal of sulfur and for recovery of NOx conversion at substantially lower temperatures. The method relies on the use of low concentrations of reductants under net oxidizing conditions, arguably by inducing a locally reducing environment on the catalyst surface through different chemical mechanisms. Reductants such as NOx + NH3, NH3, C3H6 and n-C12H26 were demonstrated to achieve the removal of sulfur species without resorting to high temperatures. It is proposed that the change of the oxidation state of Cu sites in response to these exposures, achieved through different chemical mechanisms depending on the reductant, was responsible for facilitating the removal of sulfur from the catalyst.

5585081 SOx, NOx and particulate removal system

5585081 SOx, NOx and particulate removal system

97/02388 A simultaneous SOx and NOx removal system for burning all grades of coal

97/02388 A simultaneous SOx and NOx removal system for burning all grades of coal

5540897 Improved sox, nox, and particulate removal system

5540897 Improved sox, nox, and particulate removal system

97/01479 A simultaneous SOx and NOx removal system for burning all grades of coal

97/01479 A simultaneous SOx and NOx removal system for burning all grades of coal

A New Dry Process for Simultaneous Removal of SO2 and NO from Flue Gas by Powder-particle Fluidized Bed.

A new process, which is a combination of dry processes for flue gas desulfurization and selective catalytic reduction of NOx with NH3 for simultaneous removal of SOx and NOx from the flue gas, was developed using a powder-particle fluidized bed. In the process, SOx was removed by fine sorbent, and NOx was reduced to N2 with NH3 catalyzed by coarse DeNOx catalyst in a powder-particle fluidized bed reactor. The powder-particle fluidized bed was made of a stainless steel tube of 0.053m internal diameter and 1.0m in height above the distributor. Three kinds of fine sorbents, iron oxide dust (a by-product of steel production), sodium-based sorbents (sodium bicarbonate and sodium carbonate), and copper-based sorbents (CuO, CuO•V2O5/Al2O3, and CuO•V2O5•K2SO4/Al2O3), were evaluated in this study. Coarse particles of inactive silica sand and DeNOx catalysts of WO3/TiO2 and V2O5•WO3/TiO2 were used as fluidized medium particles. The effects of various operating conditions and properties of DeSOx sorbent and DeNOx catalyst on removal of SO2 and NO were investigated. The iron oxide dust appeared to be a potential low-cost sorbent for removal of SOx and also a catalyst for reduction of NOx. Both sodium-based and copper-based sorbents had sufficient reactivity for removal of SO2. The powder-particle fluidized bed reactor was effective for simultaneous removal of SOx and NOx from the flue gas. In the proposed process, the simultaneous removal of over 90% of SO2 and NO was achieved by proper combination of fine sorbent and coarse catalyst.

Oxidation chemistry of chloric acid in NOx/SOx and air toxic metal removal from gas streams

AbstractChloric acid, HClO3, is a new oxidizer which has recently been shown to be an effective agent in the simultaneous removal of NOx and/or SOx from combustion flue gases and various chemical processes, including nitrations and metal pickling. Aqueous chloric acid readily reacts with NO and SO2 even in dilute solutions at ambient temperatures. Chlorine dioxide, ClO2, is formed as a chemical intermediate in the solution phase oxidation reactions. The oxidation by‐products of NO include NO2 and nitric acid. The ClO2 generated from the solution phase reactions also participates in gas phase oxidation reactions with NO and NO2. The combined solution phase and fast gas phase reaction chemistries provide the means for creating a new type of high performance NOx/SOx removal process. Wet scrubber based pilot plant tests have demonstrated up to 99% removal of NO.Additional recent research work has shown that chloric acid is an effective reagent for the removal of air toxic metals, such as elemental mercury, which are present in the waste gas output streams from incinerators, hydrogen from mercury cell chlor‐alkali plants, and flue gases of coal‐fired power plants. Work in this area is being conducted by Argonne National Laboratories and Olin.This paper discusses the oxidation chemistry of chloric acid and its unique solution and gas phase reactions with NO, SO2, and air toxics in wet scrubber type process equipment.