Showing papers on "Sodium sulfite published in 1978"

Simultaneous Absorption of SO2 and NO2 in Aqueous Solutions of NaOH and Na2SO3

Abstract: Experiments on the absorption of sulfur dioxide and/or nitrogen dioxide diluted with nitrogen into aqueous solutions of sodium hydroxide and sodium sulfite with a plane interface were carried out at 1 atm and 25/sup 0/C in an agitated vessel (15 cm high, 10 cm ID). From a mixture with nitrogen oxides and nitrogen, the rate of nitrogen dioxide absorption into aqueous sodium hydroxide solution was enhanced by the presence of the sulfur dioxide, but into aqueous sodium sulfite solution, the rate was reduced. Such absorption behavior arose from the change of sulfite concentration at the gas-liquid interface. Therefore, the rate of nitrogen dioxide absorption with sulfur dioxide can be predicted according to the previously proposed mechanism of competitive reactions of nitrogen dioxide with sulfite and water. These results suggest that it may be possible to develop an economical process for removing sulfur dioxide and nitrogen oxides simultaneously from stack gases by an alkaline solution, especially at high sulfur dioxide concentrations.

Dechlorination of Water for Fish Culture: Comparison of the Activated Carbon, Sulfite Reduction, and Photochemical Methods

Abstract: Activated carbon, ultraviolet radiation, and sodium sulfite were evaluated as dechlorinating agents. Activated carbon tested in a variety of commercial dechlorinators was not 100% effective in chlo...

Recovery of petroleum with chemically treated high molecular weight polymers

Abstract: Plugging of reservoirs with high molecular weight polymers, e.g. partially hydrolyzed polyacrylamide, is overcome by chemically treating a polymer having an excessively high average molecular weight prior to injection into a reservoir with an oxidizing chemical, e.g. sodium hypochlorite, and thereafter incorporating a reducing chemical, e.g., sodium sulfite, to stop degradation of the polymer when a desired lower average molecular weight and flooding characteristics are attained.

Sulfur dioxide removal process

Abstract: Sodium sulfate is purged from a sulfur dioxide removal system involving contact of a sulfur dioxide-containing gas with a solution containing sodium sulfite to absorb sulfur dioxide from the gas. The spent absorbing solution is regenerated by desorbing sulfur dioxide and recycled for further use. To avoid an unduly large build-up of sulfate in the system, at least a portion of the absorbing-desorbing medium, e.g. spent absorbing solution, containing sodium sulfate and a relatively large amount of sodium bisulfite is treated to reduce the amount of water in the medium so that there is precipitated therefrom up to about 10 weight percent undissolved solids containing sodium sulfate in greater concentration than would otherwise be obtained in the absorption-desorption cycle. The insolubles containing sodium sulfate are removed from the liquid, and the liquid can be returned to the sulfur dioxide removal system. In one preferred aspect of the invention, up to about 75 weight percent of the entire stream of spent absorbing solution is treated to precipitate therefrom up to about 10 weight percent undissolved solids which are relatively rich in sodium sulfate content. In the invention the sodium sulfate-containing solids can be separated from the liquid which is then subjected to a desorption operation to produce sulfur dioxide, and the latter operation can be conducted while maintaining at least about 25 weight percent undissolved solids in the desorption zone.

Enhancement of oxygen absorption into sodium sulfite solutions

Abstract: Oxygen absorption enhancement in a sodium sulfite solution was studied in the absence and presence of copper catalyst both for absorption across the liquid surface in a stirred cell and for absorption from individual bubbles rising through a turbulent liquid. The enhancement factor was determined from the ratio of oxygen and argon mass transfer coefficients, measured under identical experimental conditions in the same batch of liquid. It has been found that the oxygen absorption is not chemically enhanced, as long as the mass transfer coefficient, kL0, is high enough, i.e., higher than the value 1.4 × 10−4 m sec−1 for the sulfite solution we used. An analysis of our data as well as literature data indicates that the sulfite system is poorly suited for studies of the volumetric mass transfer coefficient of physical absorption (kL0a) in fermentors, inasmuch as oxygen absorption can be chemically enhanced while the degree of enhancement depends on the operating conditions of batch aeration, as well as on the concentration of trace impurities with catalytic effects upon the sulfite solution used.

Stabilization of pyrido{8 3,2-a{9 phenoxazine compounds

Abstract: Stabilized solutions of 1-hydroxy-5-oxo-5H-pyrido-[3,2-a]-phenoxazine-3-carboxylic acid (I) and of 1,5-dihydroxypyrido-[3,2-a]phenoxazine-3-carboxylic acid (II) are provided. The solutions contain a stabilizer selected from the group consisting of ascorbic acid, isoascorbic acid and water-soluble salts thereof. The solutions optionally contain an auxiliary stabilizer selected from the group consisting of sodium sulfite, sodium metasulfite and N-acetyl-L-cysteine and may also contain a solubilizer.

Method for removing sulfur dioxide

Abstract: Sulfur dioxide is removed from waste gases generated in a thermoelectric plant by contacting the gases countercurrently with an aqueous alkaline solution having a pH of about 9-12 and containing both sodium hydroxide and manganic hydroxide, whereby the sulfur dioxide reacts with the sodium hydroxide to form sodium sulfite until the pH of the solution is about 6-7 and the sodium hydroxide is substantially exhausted and wherein the sulfur dioxide then reacts with the manganic hydroxide to form manganese sulfite. The resultant sodium sulfite and manganese sulfite are oxidized and transformed into sodium sulfate and manganese sulfate respectively, by the action of oxygen in the mixture, in the presence of the manganic ion and also by the direct oxidizing action of the manganic ion.

Process for removing sulfur dioxide from gas

Abstract: There is disclosed a process for obtaining purer sodium sulfate from a mixture of solids containing sodium sulfate and sodium sulfite. The process involves contacting an aqueous slurry of the sulfate-sulfite mixture with a sulfur dioxide-containing gas under conditions which solubilize a significant amount of the sulfite as sodium bisulfite dissolved in the liquid aqueous phase. The remaining solid phase contains sodium sulfate of greater purity than in the mixture treated with sulfur dioxide. The mixture of sodium sulfate and sodium sulfite which is purified by the process may be obtained advantageously as a purge material from a process for removing sulfur dioxide from a gas stream.

Solid dechlorinating material

Abstract: PURPOSE: A specific dechlorination agent, a specific mineral ion giving material, and air curable cement such as gypsum are mixed, thereby to provide a durable dechlorinating solid material capable of producing mineral water that contains no chlorine from urban water service, etc. CONSTITUTION: Dechlorinating material such as sodium thiosulfate, sodium sulfite (0.2 to 10 wt%), mineral ion giving agent such as iron sulfate in a small quantity, and air curable cement such as gypsum or lime are mixed with water and compression molded to provide dechlorinating solid material. The resulted solid 1 is placed in a water system pipe 2 or coated on inner surface 3 of cup, etc. The cement consistuting solid base discharges Ca ion and iron sulfate gives mineral ion, thus maintaining dechlorination ability as long as it is present. As such, the process provides water that contains a variety of mineral ions and is free from chlorine. COPYRIGHT: (C)1980,JPO&Japio

Process for purging sodium sulfate from a sulfur dioxide removal system

Abstract: Sodium sulfate is purged from a sulfur dioxide removal system involving contact of a sulfur dioxide-containing gas with a solution containing sodium sulfite to absorb sulfur dioxide from the gas. The spent absorbing solution is regenerated by desorbing sulfur dioxide and recycled for further use. To avoid an unduly large build-up of sulfate in the system, at least a portion of the absorbing-desorbing medium containing sodium sulfate and a relatively large amount of sodium bisulfite, e.g. spent absorbing solution, is contacted with a treating gas containing at least a small amount of sulfur dioxide while reducing the amount of water in the medium so that a slurry is obtained having up to about 10, or even up to about 20, weight percent precipitated solids containing sodium sulfate in greater concentration than would otherwise be obtained in the absorption-desorption cycle. Preferably, the sulfur dioxide-containing treating gas is unsaturated with respect to water. The insolubles containing sodium sulfate are removed from the liquid, and the liquid can be returned to the sulfur dioxide removal system. In one preferred aspect of the invention, up to about 75 weight percent of the entire stream of spent absorbing solution is treated to form up to about 10 weight percent undissolved solids which are relatively rich in sodium sulfate content. In the invention the sodium sulfate-containing solids can be separated from the liquid which is subjected to a desorption operation to produce sulfur dioxide, and the latter operation can be conducted while maintaining at least about 25 weight percent undissolved solids in the desorption zone.

Recovering method of sodium sulfite digesting chemicals

Abstract: PURPOSE:To recover digesting chemicals, by setting up conditions of the first process, the second process and the third process in connection with each other, in order to make the ratio of sulfur content to sodium content in solid maters supplied into an oxidation reactor of the third process equal the ratio of smelt.