Studies on a New Method of Simultaneously Removing Sulfur Dioxide and Oxides of Nitrogen from Combustion Gases

Ryason, P. R.; Harkins, J

doi:10.1080/00022470.1967.10469072

Cited by 19 publications

(14 citation statements)

References 7 publications

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“…Furthermore, the ratio of the COS produced to the SC2 reduced, Y(COS)/AY(S02), decreased with decrease in temperature and the ratio of CO to SC2 concentrations, Y0(CO)/Y°(SO2). These results are consistent with those of Ryason and Harkins (1967), who reported that the optimum CO to SC2 concentration ratio to minimize the formation of COS is close to the stoichiometric value of 2.…”

Section: Resultssupporting

confidence: 92%

“…In addition to elemental sulfur and CC2, other workers (e.g., Ryason and Harkins, 1967) have reported that under suitable conditions carbonyl sulfide, COS, may be formed during the reduction of SC2 with CO. Table III presents some typical data of the amount of COS produced on the three catalysts studied in this work at various conditions. The ratio of CO to SC2 concentrations was greater than the stoichiometric value in all cases.…”

Section: Resultsmentioning

confidence: 99%

“…There has been recent interest in catalytic processes for reducing the sulfur dioxide in power plant stack gases with carbon monoxide. Ryason and Harkins (1967) found that copper-alumina and silver-alumina catalysts were effective for the simultaneous removal of both S02 and NO from stack gases. They reported that formation of COS can be minimized by maintaining the mole ratio of CO to S02 to slightly less than 2 (i.e., slightly less than the stoichiometric ratio for the complete reduction of S02 to sulfur).…”

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Catalytic Reduction of Sulfur Dioxide with Carbon Monoxide on Cobalt Oxides

Bazes¹,

Caretto²,

Nobe³

1975

Product R&D

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161°C, 46.5 mmol of Co,(CO)d., P-to-Co = 2.5, Pco = PH* = 32-35 atm. The absorption rates of synthesis gas were measured under carefully controlled gas-liquid interfacial area, thus operating the autoclave as a stirred (or Lewis) cell whereby only the solution was mixed without disturbing the interfacial area (for the theory of gas-liquid absorption combined with chemical reaction, see Danckwertz, 1970).It was found that the enhancement factor F was approximately 1 at 120' and 2.23 mmolh. of carbonyl while a value of 17 was measured at 161'C and 46.5 mmolh. of carbonyl. An F value of 1 indicates a very slow chemical reaction in the solution compared to the gas-liquid mass transfer rate. The CO concentration in the solution is thus equal, or almost equal, to the saturation value. This was confirmed by the ir analysis and further by the observation that the overall octene conversion rate was independent of the impeller speed over 1250 rpm. Thus under the prevailing conditions, the degree of PBu3 liganding is only determined by the thermodynamics of the carbonyl-PBu3 system. On the other hand, a value of 17 for F, found at 161'C, Literature CitedThe reduction of NO with NH3 on alumina-supported vanadium oxide and iron oxide-chromium oxide catalysts has been studied in flow reactors between 200 and 515'C. The rate of reduction of NO on both catalysts reaches a maximum at about 400'C and is considerably enhanced by the presence of 02. With 1000 ppm of NO and either stoichiometric or excess "3, acceleration of NO reduction is a strong function of 0 2 concentration up to 1 % 02. In simulated flue gas containing 14% C02, 5 % H20, 3% 0 2 and with NO varying from 250 to 1000 ppm, reduction of NO is a function of NH3/NO ratio from 0.5 to 1.4. The presence of SO2 in the gas mixture does not appreciably affect the reduction of NO on either catalyst at 400'C.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

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Catalytic Reduction of Sulfur Dioxide with Carbon Monoxide on Cobalt Oxides

Bazes¹,

Caretto²,

Nobe³

1975

Product R&D

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“…Both the rate of sorption and the capacity of the sorbent were low. Ryason and Harkins (1967) reported the simultaneous removal of SO2 and NO over a copper oxide under rediicinq conditions in a gas stream. Querido and Short (1973), Okay and Short (1973), and Quinlan et al (1973) have continued the development of this process.…”

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confidence: 99%

Reduction and removal of SO₂ and NO_x from simulated flue gas using iron oxide as catalyst/absorbent

Clay

Lynn

1975

AIChE Journal

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Iron oxide supported on alumina is a promising catalyst/absorbent for use in the simultaneous removal of NO, and SO, from power plant stack gases. A dry-contacting process is under development which would operate under net reducing conditions at temperatures of 370° to 540OC. Iron oxide is converted to the ferrous state, NO is reduced to Nz or NH3, and SOz is removed as ferrous sulfide or sulfate. Regeneration with air produces SO2 and reforms Fe20s.The reduction of SOz by CO and H2 was studied in fixed-bed reactors to determine the effects of temperature and of the other reactive components of flue gas (excepting fly ash) on the rate of reaction and the products formed. H2S and COS react with FeO to form FeS. Under readily attainable conditions, virtually complete removal of sulfur compounds was achieved for gas-phase residence times of about 1 to 10 ms. NO and Oz were also reduced. Conditions under which oxygen poisons the catalyst were determined. DAVID T. CLAY and SCOTT LYNN Department of Chemical EngineeringUniversity of California Berkeley, Colifornia 94720 SCOPESulfur dioxide and nitric oxide are major air pollutants in the United States. Fossil-fueled power plants are major sources of both. Wet processes for SO2 removal are currently being developed commercially, but to date no process for simultaneous SO2 and NO removal has passed the laboratory scale. A dry removal process would be preferred, since this would avoid flue-gas reheating, the problems of contacting the gas with a liquid or slurry, and the crystallization phenomena usually encountered in flue-gas scrubbing. The objective of this study was to develop a dry process which not only achieves high NO and SO2 removals, but also converts NO to innocuous materials and SO2 to a salable product and is potentially economical to operate.The process flow sheet is shown in Figure 1. Iron oxide, supported on alumina, acts as a catalyst for the reduction of both SOz and NO by CO and H2. Simultaneously, it acts as an absorbent for sulfur compounds, converting them to FeS. The catalyst/absorbent is in the form of fine pellets (0.05 to 0.10 mm) and contacts the gas as a falling bed in concurrent flow at 370° to 540OC. The solid is regenerated with air at 675OC to produce a rich stream of SO2, suitable for conversion to H2SO4 or elemental sulfur. Fez03 is reformed in the particles. Experiments in fixed-bed reactors using mixtures of helium and one or more reactant gases were run to demonstrate the basic process chemistry, to estimate rates for preliminary design purposes, and to look for interfering reactions. A preliminary estimation of the capital and operating costs of the process was made on the basis of the results obtained. CONCLUSIONS AND SIGNIFICANCEThe overall reactions listed in Table 1 were shown to proceed rapidly at 370" to 540°C in fixed-bed reactors using pellets of supported iron oxide 3.2 mm x 3.2 mm or particles 0.25 to 0.50 mm diameter. Iron oxide was reduced to the ferrous state, SO2 was reduced by both CO and H2, and the sulfur was absorbed ...

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“…A correlation between both this effect and the effect of the oxidizing or reducing nature of the catalyst/ absorbent on NH selecticity was found. 1 1 1 1 1 1 1 1 1 1 1 1 1 Copper Oxide was reported to accomplish simultaneous S0" and NO removal by forming S and N_ (Quinlan, 1973 andRyason, 1967 A combination of nickel and iron onides was tested to see if the amount of NH produced could be decreased. Klimisch (1973) has demonstrated the ability of Ni to decompose NH, on a Pt-Ni-Al catalyst at 500°C.…”

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Development of a feasible process for the simultaneous removal of nitrogen oxides and sulfur oxides from fossil fuel burning power plants

Clay

Lynn

1974

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Studies on a New Method of Simultaneously Removing Sulfur Dioxide and Oxides of Nitrogen from Combustion Gases

Cited by 19 publications

References 7 publications

Catalytic Reduction of Sulfur Dioxide with Carbon Monoxide on Cobalt Oxides

Catalytic Reduction of Sulfur Dioxide with Carbon Monoxide on Cobalt Oxides

Reduction and removal of SO₂ and NO_x from simulated flue gas using iron oxide as catalyst/absorbent

Development of a feasible process for the simultaneous removal of nitrogen oxides and sulfur oxides from fossil fuel burning power plants

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Studies on a New Method of Simultaneously Removing Sulfur Dioxide and Oxides of Nitrogen from Combustion Gases

Cited by 19 publications

References 7 publications

Catalytic Reduction of Sulfur Dioxide with Carbon Monoxide on Cobalt Oxides

Catalytic Reduction of Sulfur Dioxide with Carbon Monoxide on Cobalt Oxides

Reduction and removal of SO2 and NOx from simulated flue gas using iron oxide as catalyst/absorbent

Development of a feasible process for the simultaneous removal of nitrogen oxides and sulfur oxides from fossil fuel burning power plants

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Reduction and removal of SO₂ and NO_x from simulated flue gas using iron oxide as catalyst/absorbent