用硫化氢气体制造硫酸

简述硫化氢气体生产硫酸的发展过程。对硫化氢制酸常见的鲁奇湿接触法流程的丹麦托普索公司的WSA流程及特点作了介绍。在目前我国硫回收量不断增加及环境保护越来越严格的形势下,硫化氢制酸有着一定的发展前途。     

Evolution of carbon disulfide and hydrogen sulfide in spinning viscose fibres

Conclusions It has been found that the rate of decomposition of the byproducts and of cellulose xanthate differ considerably from the rate of evolution of the gases formed.Carbon disulfide in the chemically unbounded state forms stable emulsions with the components of the precipitation bath.The kinetics of carbon disulfide evolution in the plasticizing treatment of viscose fibre is described by a zero order reaction equation.Translated from Khimicheskie Volokna, No. 6, pp. 44–45, November–December, 1985.     

Wet spinning of asymmetric hollow polysulfone fibres by the double spinning bath method

The possibility of fabricating an asymmetric hollow fibre from polysulfone in a one-stage process with the double spinning bath method was demonstrated. A correlation was established between the quality of the selective layer and the value of the diffusion coefficient of the solvent in the precipitant.Russian Institute of Chemical Technology, Moscow. Translated from Khimicheskie Volokna, No. 6, pp. 24–26, November–December, 1993.     

Direct oxidation of hydrogen sulphide to sulphur using impregnated activated carbon catalysts

Low concentrations of H₂S were directly oxidized to sulphur and small quantities of SO₂, over seven different activated carbons with or without impregnation. The effectiveness of virgin activated carbon was tested at 175°C, 700 kPa, and O₂/H₂S ratio with 5% greater than stoichiometry. The conversion of H₂S was 99.9 mol% with SO₂ production of 3–6%, for 360 min runtime for Fisher coconut shell activated carbon and 648 min for Envirotrol bituminous (EB) activated carbon. Then the activated carbons became deactivated due to deposition of sulphur on the surface. Under these conditions mesoporous activated carbons such as EB and Hydrodarco had the longest breakthrough time. The addition of 5.5 wt% ammonium iodide, potassium iodide and potassium carbonate individually to EB decreased the production of SO₂ while having minimal effect on the overall H₂S conversion. The addition of 5.5 wt% NH₄I decreased the average SO₂ production from 2.5% to 0.9%. The activation energy for the H₂S oxidation on the 5.5 wt% NH₄I on EB activated carbon was determined to be 40 kJ/mol.     

Catalytic oxidation of hydrogen sulphide by air over an activated carbon fibre

Activated carbon fiber (ACF), FN-200CF-15, made from coal tar, oxidized hydrogen sulphide effectively to sulphuric acid at an inlet concentration of 200 ppm and space velocity (SV = flow rate/packing volume) of 100 h⁻¹ (sulphur load 11 g-S/day kg-fiber) for one and a half months only by keeping the moisture content of ACF more than 50%. This phenomenon is different from granular activated carbon (GAC) reported previously.     

The adsorption of hydrogen and hydrogen sulphide on tungsten sulphide; isotherm and neutron scattering studies

Adsorption isotherms for hydrogen and hydrogen sulphide on a WS₂ surface have been measured at 400°C at pressures up to 1 at. Inelastic neutron scattering spectra have been recorded for the materials produced. Both hydrogen and hydrogen sulphide adsorb dissociatively to produce S-H bonds. Hydrogen sulphide adsorption is smaller than that of hydrogen and it is suggested that this is because dissociation leads also to sulphidation of the surface vacancies at which the adsorption occurs. In both cases the hydrogen atoms produced as a consequence of the dissociation are able to diffuse over the surface to form bonds to available sulphur atoms.     

Electrolysis of liquid hydrogen sulphide

Electrolysis of liquid hydrogen sulphide has been investigated. Pyridine was used to provide conductivity. The cathodic current efficiency for hydrogen production was 99.7 ± 0.5%; sulphur was the major anodic product with a current efficiency of 84.2 ± 4.5%. Ohmic losses in the solution were the largest source of voltage drop.     

The solubility of mixtures of carbon dioxide and hydrogen sulphide in an aqueous dipa solution

The solubility of mixtures of carbon dioxide and hydrogen sulphide in an aqueous solution of di-isopropanolamine (2.5 kmol m^?3 DIPA) has been measured at temperatures of 40 °C and 100°C. Partial pressures of CO₂ ranged from 2.0 to 5991 kPa, while partial pressures of H₂S ranged from 1.3 to 4126 kPa.     

The temperature-programmed desorption of hydrogen from copper surfaces

The desorption kinetics of H₂ from a Cu/ZnO/Al₂O₃ catalyst for methanol synthesis were studied under atmospheric pressure in a microreactor set-up by performing temperature-programmed desorption (TPD) experiments after various pretreatments of the catalyst. Complete saturation with adsorbed atomic hydrogen was obtained by dosing highly purified H₂ for 1 h at 240 K and at a pressure of 15 bar. The TPD spectra showed symmetric H₂ peaks centered at around 300 K caused by associative desorption of H₂ from Cu metal surface sites. H₂ TPD experiments performed with different initial coverages resulted in peak maxima shifting to higher temperatures with lower initial coverages indicating that the desorption of H₂ from Cu is of second order. The microkinetic analysis of the TPD traces obtained with different heating rates yielded an activation energy of desorption of 78 kJ mol^–1 and a corresponding frequency factor of desorption of 3×10¹¹ s^–1> in good agreement with the kinetic parameters obtained with Cu(111) under UHV conditions.