Eizo Sada

Gas absorption accompanied by complex chemical reactions — III Parallel chemical reactions

Abstract Gas absorption accompanied by the parallel chemical reactions is discussed from the view-point of the film theory. The approximate solutions for the ratio Φ are derived by the same method described in our previous papers and compared with the analytical or numerical solutions for several cases. The difference of the ratio Φ between the approximate and the exact solutions is only a few per cent.

Gas absorption accompanied by complex chemical reactions- I Reversible chemical reactions

Abstract A solution based on the film theory is presented for gas absorption accompanied by a generalized, reversible chemical reaction of the form γAA+γBB⇋γEE+γFF. The approximate solution for the ratio of mass transfer coefficients, Φ, is derived and compared graphically with the exact numerical solutions for several limiting cases. It is shown that the error of this approximate method is less than several per cent.

Gas absorption accompanied by complex chemical reactions - II Consecutive chemical reactions

Abstract Based upon the film theory, the approximate solutions for gas absorption accompanied by two consecutive chemical reactions of the forms γ A A +γ B B →γ C C + Product,γ A′ A′ +γ C C →γ C C →γ B B and γ A A +γ B B →γ C C ,γ A A +γ ′ C C Product, are derived and compared with the numerical solutions. For the case of equal diffusivities, the approximate and numerical solutions agree with each other within a few per cent.

Gas absorption accompanied by complex chemical reactions-IV: Unsteady state

Abstract For gas absorption accompanied by ( m,n )-( p,q )-th order reversible, consecutive and parallel chemical reactions, the approximate solutions based on the penetration and surface renewal theories are derived under the condition of equal diffusivities, and compared with the approximate solution based on the film theory to manifest the generalized solution being suitable for three theories. For the case of reversible chemical reaction, the approximate solution based on the penetration theory is compared with the numerical solution to examine the accuracy of Hikita and Asais approximation in the unsteady state. It is found that the division of the approximate solution from the numerical solution is only a few per cent.

Absorption of carbon dioxide into aqueous solutions of ethylenediamine: Effect of interfacial turbulence

Abstract Absorption rates for carbon dioxide into aqueous ethylenediamine solutions were measured in a laminar liquid jet, a wetted-wall column and a quiescent liquid absorber to investigate the chemical absorption mechanism and the reaction kinetics over a wide range of contact times. From the chemical absorption data in the laminar liquid jet with surface-active agent, the value of the rate constant for the second order reaction was derived as 1.75 × 104 l mol−1 s−1. Additional experiments were carried out on the tracer desorption of ethylene from aqueous ethylenediamine solutions saturated with ethylene to check and verify effects due to interfacial turbulence. We conclude that the Marangoni effect cannot be neglected even for such a short contact time as that in a laminar liquid jet.

Simultaneous absorption with reaction in a slurry containing fine particles

Abstract The simultaneous absorption of two gases accompanied by chemical reaction into a slurry of fine suspended particles was numerically analysed using the model obtained with some extension of the corresponding single gas absorption. Experiments were performed for the simultaneous absorption of sulfur dioxide and carbon dioxide with a plane gas—liquid type stirred tank absorber. The experimental results were satisfactorily elucidated by the proposed model and it is suggested that when accompanied by sulfur dioxide absorption, carbon dioxide may almost be regarded as an inert gas.

The film condensation of mixed vapour in a vertical column

Abstract In the film condensation of mixed vapour, the heat-transfer coefficient for the liquid film is given by the same equation as previously presented for the condensation of pure vapour. The dependence of the mass-transfer coefficient in vapour phase upon the rate of condensation is explained by the film theory, but for the mass transfer in liquid film, the agreement of the experimental values of the masstransfer coefficients with the values calculated on the basis of the penetration theory is excellent.

A study of interfacial flow due to concentration difference

Abstract Experiments were carried out to study the effect of concentration differences on the surface-velocity distribution. The surface-velocity induced by feeding the surface-tension lowering material onto the surface of the stagnant liquid was measured in a similar type of apparatus to that used by Ruckenstein et al. [1]. The system studied was ethanol-water. From the experimental results, the dependence of surface-velocity distribution on the bulk viscosity of the solution, degree of surface contamination and concentration and feed rate of alcohol, was discussed.

Variation of the enhancement factor in gas absorption with order of chemical reaction

Abstract The enhancement factor for the gas absorption with the two-step reversible and irreversible consecutive reaction, 2 A ⇌ A *+ A and A *+ B → P in the film theory was derived by using the Van Krevelen approximation, and was compared with the exact numerical solution. The difference between the approximate and the exact enhancement factors is within a few per cent. The relation of the enhancement factor to the order of reaction in the whole regime from a simple irreversible reaction to an instantaneous rapid reaction was discussed.

Chromatographic Removal of Endotoxin from a Macromolecular Antitumor Antibiotic SN-07.

高分子抗腫瘍性抗生物質SN-07から, イオン交換クロマトグラフィー (IEC) および疎水クロマトグラフィー (HIC) によりエンドトキシンを除去した.IECおよびHIC用樹脂に吸着したエンドトキシンは, アルカリ-エタノールによる洗浄後, 洗浄液中の塩濃度の上げ下げを繰り返す方法により除去できることがわかった.この方法で調整したエンドトキシンフリーカラムによりSN-07を精製したところ, Sepabeads FP-DA 13を用いたIECでは負荷した量の95.5%のエンドトキシンが除去された.HICではリガンド濃度の異なる2種類の樹脂 (Sepabeads FP-PH 12およびFP-PH 13) についてSN-07の吸脱着を行う塩濃度でのエンドトキシンの平衡吸着能を調べたところ, 両樹脂ともに吸着量の差は小さかった. カラムを用いたSN-07の精製においても, エンドトキシンの除去率はFP-PH12で92.8%, FP-PH13では95.7%といずれも高く, 上記平衡吸着能の結果に対応した.