Potassium carbonate solutions process

Benfield process Removal of carbon dioxide from fuel gases, such as those obtained by gasifying coal in the Lurgi process, by countercurrent scrubbing of the gases by hot potassium carbonate solution. 

Catacarb process An extraction process used to remove carbon dioxide from process gases by scrubbing the hot gases with potassium carbonate solution containing additives which increase the hydration rate of the gas in the solution. The Vetrocoke process is similar. See Benfield process. 

In one process the carbon dioxide is removed using potassium carbonate solution, potassium hydrogencarbonate being produced ... 

Three major sources in the kraft process are responsible for the majority of the H2S emissions. These involve the gaseous waste streams leaving the recovery furnace, the evaporator and the air stripper, respectively denoted by R), R2 and R3. Stream data for the gaseous wastes are summarized in Table 8.8. Several candidate MSAs are screened. These include three process MSAs and three external MSAs. The process MSAs are the white, the green and the black liquors (referred to as Si, S2 and S3, respectively). The external MSAs include diethanolamine (DBA), S4. activated carbon, Sj, and 30 wt% hot potassium carbonate solution, S6. Stream data for the MSAs is summarized in Table 8.9. Syndiesize a MOC REAMEN that can accomplish the desulfurization task for the three waste streams. 

A mixture of 10.3 g of thiophene-20 -methylacetic acid [prepared by process of Bercot-Vat-teroni, et al.. Bull. Soc. Chim. (1961) pp. 1820-211, 11.10 g of benzoyl chloride and a suspension of 23.73 g of aluminum chloride in 110 cc of chloroform was allowed to stand for 15 minutes and was then poured into a mixture of ice and hydrochloric acid. The chloroform phase was extracted with a 10% aqueous potassium carbonate solution and the aqueous alkaline phase was acidified with N hydrochloric acid and was then extracted with ether. The ether was evaporated off and the residue was crystallized from carbon tetrachloride to obtain a 54% yield of 5-benzoyl-thiophene-20 -methylacetic acid melting at 83°C to 85°C. The... 

Benfield process aqueous potassium carbonate blocking of pores of methanation catalyst by evaporation of potassium carbonate solution... 

The H2 is separated from C02 and purified at the final stage of the process. Older variations of the SMR process (Figure 2.5a) used solvents to remove the acid gas (C02) from the gaseous stream after WGS reactors. Solvents commercially used for C02 removal in the gas separation unit include monoethanolamine (most preferred and widely used solvent), water, ammonia solutions, potassium carbonate solutions, and methanol. This operation allows the reduction of C02 concentration in the process gas to about 100 ppm. The remaining... 

Carbosolvan One of the several processes for absorbing carbon dioxide from gases, using hot potassium carbonate solution. See also Benfield, Carsol, CATACARB, Giammarco-Vetrocoke, Hi-Pure. 

CATACARB [Catalyzed removal of carbon dioxide] A process for removing carbon dioxide and hydrogen sulfide from gas streams by absorption in hot potassium carbonate solution containing a proprietary catalyst. Developed and licensed by Eickmeyer and Associates, KS, based on work at the U.S. Bureau of Mines in the 1950s. More than a hundred plants were operating in 1997. See also Benfield, Carsol, Hi-pure, Giammarco-Vetrocoke. 

CONOSOX A complex flue-gas desulfurization process using potassium carbonate solution as the wet scrubbing medium. The product potassium bisulfite is converted to potassium thiosulfate and then reduced with carbon monoxide to potassium carbonate for re-use. The sulfur is recovered as hydrogen sulfide, which is converted to elemental sulfur by the Claus process. Developed by the Conoco Coal Development Company and piloted in 1986. 

HiPure A variation on the Benfield process, using two stages of scrubbing by hot potassium carbonate solution in order to reduce the carbon dioxide contents of gases to very low levels. See also Carsol, CATACARB, Giammarco-Vetrocoke. 

Potassium bromide also can be prepared by treating iron turnings with a 35 wt% aqueous solution of bromine. The product ferrosoferric bromide is boded in potassium carbonate solution containing a slight excess of 15% potassium carbonate (Dancy, W.B. 1980. Potassium Compounds. In Kirk-Othmer Encyclopedia of Chemical Technology, 3 i ed. p. 963. New York Wiley Interscience). The method does not involve bromate formation. The second step of the process may be represented in the foUowing reaction ... 

In general, the direct-oxidation processes employ a redox couple that has sufficient oxidation potential to convert H2S into elemental sulfur but insufficient potential to oxidize sulfur to higher states. Examples of materials that have this redox potential are vanadium compounds, arsenic compounds, iron compounds, and certain organic species. Typically, the redox materials, dissolved in a hot potassium carbonate solution with the species in its oxidized form, contacts the I S-laden gas and the H2S dissolves as the hydrosulfide. This sulfur reacts with the redox couple, forming elemental sulfur and the reduced state of the couple. Airblowing of the solution reoxidizes the couple and removes the elemental sulfur from solution as a product froth. 

Two processes are known by the Giammarco-Vetrocoke name. Both processes use an aqueous solution of sodium or potassium carbonate and arsenite to absorb acid gases. Some variations of the process use glycine instead of arsenite to activate the potassium carbonate solution. In one process, the solution is used to extract carbon dioxide from natural gas or synthesis gas. In the other, hydrogen sulfide is extracted from coke-oven or synthesis gas and yields elemental sulfur from a complex sequence of reactions. In 1992, more than 200 plants were operating1. 

Summary KDN can be prepared directly from ammonium carbamate by first, reacting the carbamate with nitronium tetrafluoroborate in the presence of acetonitrile to form an intermediate, the free acid of ADN, which need not be isolated. This intermediate is then treated with a potassium carbonate solution in the presence of ether. The KDN is then recovered by evaporation of the reaction mixture, followed by treatment with a solvent mixture, to remove impurities. The product is recovered by evaporation, and then reciystallized from butanol to form high purity KDN. Commercial Industrial note For related, or similar information, see Application No. 539,647, June 18, 1990, by SRI International, to Jeffrey C. Bottaro, Mountain View, CA, Robert J. Schmitt, Redwood City, CA, Paul E. Penwell, Menlo Park, CA, and David S. Ross, Palo Alto, CA. Part or parts of this laboratory process may be protected by international, and/or commercial/industrial processes. Before using this process to legally manufacture the mentioned explosive, with intent to sell, consult ary protected commercial or industrial processes related to, similar to, or additional to, the process discussed in this procedure. This process may be used to legally prepare the mentioned explosive for laboratory, educational, or research purposes. 

Combinations of physical and chemical absorption are also used, as in Shell s Sulfinol process in which a mixture of diisopropanolamine and sulfolane in water is utilized. For the hydrogen sulfide-free gases from the steam-reforming process, chemical scrubbing with activated potassium carbonate solutions or alkanolamines is preferred. In the case of hydrogen sulfide-containing gases from the partial oxidation process, physical absorption alone or in combination with chemical absorption is preferred. 

The reactors are supplied with g mixture of ethylene, oxygen and recycle gas acting as diluents. The recirculation stream is dissolved in a potassium carbonate solution to reduce the carbon dioxide content In this process, which features closed-circuit circulation of inert gases, purge and hence ethylene losses (0.5 per cent of the amount introduced) are minimal. - - ... 

Processes employing alkaline salts, espedally potassium carbonate solutions, are strongly influenced in their operation and their performance by the partial pressnre of the acid gases. Hence they are unsuitable at low or high pressures for the absorption of a low-content feedstock component. It is preferable to combine high pressure with a sufficient C02 concentration. 

Various versions of the hot potash process are today offered by a number of different licensors. Apart from measures intended to reduce heat demand, these versions differ by their additives to the potassium carbonate solution, which are in some cases intended to activate the reaction and in others to prevent corrosion. 

---