Siu-Ming Yih

GAS ABSORPTION INTO WAVY AND TURBULENT FALLING LIQUID FILMS IN A WETTED-WALL COLUMN

Experiments are conducted for gas absorption in a long wetted-wall column. Liquid-side mass transfer coefficients are measured for absorption of CO2 and O2 into falling water films on the outside of a stainless steel pipe 2.72 cm OD and 183 cm absorption length. The liquid film Reynolds number ranges from 129 to 10500 which encompasses the wavy-laminar, wavy-transition and turbulent flow regimes. The experimental data are correlated by a dimensionless equation of the form kt = (ktD) (v2/g) 1/3 = a-Rep-Sc1/2. The correlation is well supported by a viscosity-damped turbulence model at the gas-liquid interface which tends to confirm that viscosity is probably the major mechanism causing eddy damping and not surface tension as proposed by Levich and Davies. The form of the above correlation also represents previous experimental work at different temperatures and for different gases quite well.

Simultaneous absorption of hydrogen sulphide and carbon dioxide into potassium carbonate solution with or without amine promoters

Abstract Simultaneous absorption of hydrogen sulphide and carbon dioxide into potassium carbonate and amine-promoted potassium carbonate solutions has been perf

ABSORPTION OF NO AND SO2 IN FE(II)-EDTA SOLUTIONS I. ABSORPTION IN A DOUBLE STIRRED VESSEL

Abstract A double stirred vessel with a plane gas-liquid interface was used to measure the absorption rates of (i) NO in aqueous solutions of Fe(II)-EDTA, (ii) NO and SO2 in mixtures of Fe(II)-EDTA and Na2SO3 or Na2SO3, at 25°C and 1 atm. The forward rate constants, k2, of the complexing reaction NO + Fe(II)-EDTA→Fe(II)(EDTA)(NO) at various liquid temperatures between 25-80°C and liquid concentrations between 0.01-0.05 mol/dm3 were deduced from chemical absorption theory. The results showed that k2 increases only slightly within 25-80°C and 0.01-0.05 mol/dm3. The rate of absorption of NO during the simultaneous absorption of NO and SO2 was higher than the rate of single NO absorption when Na2SO3 was added to the Fe(II)-EDTA. Na2SO3 can replace Na2SO3, when SO2 is absorbed together with NO.

SIMULTANEOUS ABSORPTION OF CARBON DIOXIDE AND HYDROGEN SULFIDE IN HOT CARBONATE SOLUTIONS IN A PACKED ABSORBER-STRIPPER UNIT

An experimental investigation for the simultaneous absorption of CO2 and H2S in 20 wt% hot K2CO3 solution have been conducted in a pilot scale packed absorber-stripper. The effects of liquid circulation rate, gas flow rate, inlet gas composition, steam pressure at bottom of stripper, and DEA promoter concentration, on the individual gas removal % and stripping efficiency were studied. The results showed that the performance of the absorber and stripper influenced one another and so must be considered together.

HOLDUP MEASUREMENT IN A SCHEIBEL EXTRACTION COLUMN

Abstract ABSTRACT The total holdup of a dispersed organic phase in a rotary-agitated Scheibel liquid-liquid extraction column of the first type is studied experimentally. The column is 2 inches in diameter and contains 11 stages with a 4-inch height packed section and a 1-inch height mixing section. The packed section is made of stainless steel wire mesh packing with a 93.74% free area and acts as a settler for the coalescence of droplets. Three systems are studied: benzene/water, methyl isobutyl ketone (MIBK)/water and 20% TBP-80% kerosene/1 M nitric acid. The effects of different phase flow rates and rotation speeds (300-670 rpm) on the dispersed phase holdup are investigated. The results show that the holdup increases with increasing dispersed phase flow rate but does not vary with continuous phase flow rate. For benzene, the holdup is large at low rotation speeds and decreases with increasing rotation speed until a minimum holdup is reached, after this transition point, the holdup increases with incre...

GAS ABSORPTION INTO WAVY AND TURBULENT NON-NEWTONIAN FALLING LIQUID FILMS IN A WETTED-WALL COLUMN

Average Him thickness and liquid-side mass transfer coefficient for the absorption of oxygen in wavy and turbulent power-law model falling liquid films are measured. Considerable reduction in (he film thickness with resulting increase in the mass transfer coefficient are obtained as compared to that predicted by the theoretical laminar flow equation assuming no slip at the wall.

SIMULTANEOUS ABSORPTION OF C02 AND H2S IN SULFINOL SOLUTIONS IN A SET OF PACKED ABSORBER-STRIPPER

Simultaneous absorption of CO2 and H2S in a Sulfinol solution have been studied in a set of small pilot scale packed absorber-stripper. Data were presented on the effects of varying liquid circulation rate, feed gas flow rate, feed gas composition and steam pressure at bottom of stripper, on the individual gas removal %, steam stripping efficiency and overall volumetric gas-phase mass transfer coefficient for absorption. A comparison with an earlier work on absorption into 20% hot potassium carbonate solution in the same apparatus show that the influence of operating variables on the performance of the absorber-stripper unit is qualitatively similar for both types of solvents except that the steam stripping efficiency of the Sulfinol system is much more superior than the 20% hot carbonate system under similar conditions. This shows that the hybrid nature of the Sulfinol solvent gives a much better regeneration efficiency than chemical solvents in simultaneous CO2 and H2S removal

PERFORMANCE OF A WETTED-WALL SHEET BUNDLE COLUMN

The performance of a wetted-wall sheet bundle column with vertically aligned sheets placed inside as liquid film supports was investigated as an alternative to a wetted-wall fiber bundle column used for gas and liquid contacting. It avoids or simplifies some of the design problems associated with using fibers and still retains the advantages possessed by the fibers such as low pressure drop and high mass transfer coefficient. A comparison with the conventional Raschig ring packings and stainless steel tube bundles show that the fibers and sheets which were made of light weight material has definite advantages in reducing the weight and cost of the packing material in the column substantially

ABSORPTION OF NO AND SO2 IN FE(II)-EDTA SOLUTIONS II. PACKED COLUMN SIMULATION

Abstract Two methods were applied in simulating the height of a packed column required for the removal of NO and SO2 by absorption into Fe(II)-EDTA solutions. The first method used a double-stirred cell to simulate a packed column by matching the gas- and liquid-phase mass transfer coefficients of the two device. The second method used the differential mass balance including reaction kinetics. Data taken in an 8 cm diameter, 40 cm packed height column and in a double-stirred cell were employed in illustrating the methodology. The two methods of prediction were quite satisfactory.