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Showing papers in "Industrial & Engineering Chemistry Process Design and Development in 1979"



Journal ArticleDOI
TL;DR: In this paper, the parameters for 46 group combinations are provided and a new main group for sulfones is introduced, for which the group interaction parameters for eight main groups are fitted.
Abstract: The group contribution method UNIFAC has become very popular because of its large range of applicability and its reliable predictions of vapor−liquid equilibria. With the help of new data stored in the Dortmund Data Bank (DDB), many gaps in the existing UNIFAC parameter matrix have been filled, and many new main groups have been added to the parameter table. In this paper, the parameters for 46 group combinations are provided. Additionally, a new main group for sulfones is introduced, for which the group interaction parameters for eight main groups are fitted.

354 citations












Journal ArticleDOI
TL;DR: G, = noise generator k = integral value of B/T K, = controller gain K, = process gain n, = Laplace transform variable s, = coefficients of the polynomial 6(B) (denominator of G,(B)) t = time T = sampling interval X, (B) = transfer function of forward loop controller.
Abstract: G, = noise generator k = integral value of B/T K , = controller gain K , = process gain n, = noise sequence s = Laplace transform variable s, = coefficients of the polynomial 6(B) (denominator of G,(B)) t = time T = sampling interval X,(B) = transfer function of forward loop controller (Table 111) y = system output ut = controller signal a = relative perturbation in process parameters = relative perturbation in process time delay r ( B ) = polynomial resulting from factorization (Appendix) y, = coefficients of y ( B ) 6(B) = denominator of G,(B)


Journal ArticleDOI
TL;DR: In this paper, a channelling flow model was developed which gave a satisfactory explanation of the multiplicity of hydrodynamic states dependent on the past flow history and the existing correlations proved adequate although the parameters differed from those developed for larger packings and an appropriate factor was needed to account for the flow history effect.
Abstract: Correlations were developed and tested for predicting the hydrodynamic performance of cocurrent trickle bed reactors packed with small particles (0.5-1.85 mm). Such reactors show a multiplicity of hydrodynamic states dependent on the past flow history. In general, the existing correlations proved adequate although the parameters differed from those developed for larger packings and an appropriate factor was needed to account for the flow history effect. A channelling flow model was developed which gave a satisfactory explanation of the multiplicity of hydrodynamic states.


Journal ArticleDOI
TL;DR: In this paper, the absorption rate of lean NO(x) as encountered in flue gases in aqueous mixed solutions of NaClO2 and NaOH was carried out using a stirred vessel with a plane interface at 25 C and atmospheric pressure.
Abstract: The absorption of such lean NO(x) as encountered in flue gases in aqueous mixed solutions of NaClO2 and NaOH was carried out using a stirred vessel with a plane interface at 25 C and atmospheric pressure. The rate of NO2 absorption was analyzed by the chemical absorption theory under the fast-reaction regime. The reaction which prevailed was found to be the parallel reactions involving oxidation and hydrolysis, and to be second order with respect to NO2. The second-order rate constant for the hydrolysis was evaluated as 3.09 x 10 to the 8th L/mol s. The order of reaction relative to ClO2(-) was derived as unity for chlorite concentrations greater than 1.0 M. The third-order rate constant for the oxidation was derived as 7.32 x 10 to the 8th (L/mol)-squared/s at /NaOH/ 0.20 M. For the absorption of NO, there appears to be a gradual jump in absorption rate at the interfacial concentration of NO ranging from 5 x 10 to the -7th to 2 x 10 to the -6th mol/L. Above this transition region, the order of reaction in NO approaches 2, whereas below the transition region, the order of reaction becomes unity.











Journal ArticleDOI
TL;DR: In this paper, a simple mathematical model of a single irreversible reaction with n-th order, concentration-independent catalyst deactivation is proposed, which predicts the time-temperature relationship for the constant-conversion mode of operation.
Abstract: A simple mathematical model of a single irreversible reaction with n-th order, concentration-independent catalyst deactivation is proposed. The model predicts the time-temperature relationship for the constant-conversion mode of operation and can be used to optimize temperature policy in a batch reactor. The applicability of the model to pilot-plant data from hydrocracking of gas oil and catalytic reforming of naphtha is demonstrated and the effects of process variables, such as start-of-run temperature, space velocity, and conversion level on the fouling rate are examined. The model has successfully described both the linear and exponential portions of the reaction temperature-time curves and demonstrated a linear correlation (on a logarithmic basis) between fouling rate and the work function, i.e., the product of conversion and space velocity, of the catalyst.