摘要:

AbstractThe process of recrystallization of apatite phosphogypsum (PHG) in a solution ammonium sulphate (AS) with the subsequent decomposition of the binary salt was investigated and the resulting highly dispersed products with a low P2O5content have been discussed. The following effects were examined: (NH4)2SO4concentration, the quantity of ammonium sulphate, the reaction temperature of phosphogypsum with (NH4)2SO4solution, the time of treatment of phosphogypsum with (NH4)2SO4solution and the decomposition of the binary salt, as well as the liquid/solid ratio for the binary salts, Based on the results of the chemical and X‐ray analysis, it was established that, depending on the technological conditions of the process of recrystallization, binary salts of (NH4)2SO4·CaSO4·H2O and of (NH4)2SO4·CaSO4·H2O and of (NH4)2SO4·5 CaSO4·H2O were formed. As a result of the investigations carried out, a product with a low P2O5content, suitable for direct processing to secondary products has been p

ISSN:0930-7516    

DOI:10.1002/ceat.270190112

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractIn this paper a novel process for biotechnological abatement of hydrogen sulphide is presented which details the fundamentals of chemical and biological phenomena involved. The process is based on the combination of two steps to form a closed cycle which has special enviornmental advantages. The chemical step corresponds to the abatement reaction itself with absorption of the gas in a ferric solution. The biological step is related to the regeneration of the absorbing solution by means of specific bacterial strains. Particular interest is devoted to the biological kinetics of the regeneration stage, where several inhibition phenomena appear, and are also related to parameters such as temperature and pH. Results of experimental runs of gas absorption in a laboratory scale plant are also described.

ISSN:0930-7516    

DOI:10.1002/ceat.270190113

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe dynamic behavior of a Pt‐Rh/CeO2‐Al2O3three‐way catalyst (TWC) under pulsed flow operation conditions (intermittent mode), such as occur in a newly developed hybrid drive system, has been studied experimentally in a laboratory apparatus with simulated exhaust gas. The parallel hybrid system is based on the combination of an Otto‐cycle engine with an electric motor and a flywheel providing a short‐term energy storage. This configuration permits intermittent charging of the flywheel by the combustion engine which runs only during about 10% of the driving time. Each exhaust gas pulse (duration typically ca. 3 s) is proceeded by an air pulse, which results from the filling of the engine cylinders with air at start up and shut off. Experimental studies indicated that the air pulses have a negative impact on the performance of the catalytic converter, reducing the inherent benefits resulting from the intermittent operation mode of the combustion engine.Forced asymmetric λ‐cycling during exhaust pulse was found to be most beneficial for improving catalyst performance. A simple reduced kinetic model derived from a Langmuir‐Hinshelwood model for CO oxidation, which was extended by introducing CO and O2equivalents to mimic the complex exhaust gas, was used to describe the dynamic behavior of the TWC. The model proved to be useful for finding the optimal λ‐cycling conditions. Experiments with the real Otto‐cycle engine exhaust proved that the reduced kinetic model is suitable for use in a cl

ISSN:0930-7516    

DOI:10.1002/ceat.270190114

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0930-7516    

DOI:10.1002/ceat.270190101

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY