Chemical Engineering Technology

Sulphur, one of the oldest inorganic fungicides, is mixed in different formulas with other organic or
inorganic products in order to increase its biological activity and to cover a larger area of different fruit
diseases treatment. In this paper, sulphur, as sulphides, polysulphides and thiosulphates, is one of the main
components in such a microemulsioned formulation, which include both overbasic potassium naphthenates and
oleates. Dilution and carbonation of the microemulsion results in a step-by-step gradual hydrolysis of all
initially stable entities. Organic hydrolysates may cover up any surface with an adherent layer incorporating
inorganic sulphur amorphous hydrolysates. After complete hydrolysis through carbonation most of the sulphur
compounds pass mainly to nanoparticulate elemental sulphur along with other of its neutral or acid salts.
Calcium and magnesium ions from hard dilution waters may contribute to micelle aggregation hydrolysate layer
adherence. This composite fungicide gather some of the most required properties of this class of products:
biological active entities generation as nanosized particulate hydrolysates straight on the surfaces subsequently
their application, amorphous elemental sulphur and sulphur compounds, mixed organic/inorganic micelle
aggregates ready to penetrate plasma cell membranes, etc. The experimental data encompass properties design
and commercial Frucol brand behavior as foliar product.

Risk assessment is the tool for maintaining perfect safety management systems and aiding sustainable process design, with hazard identification as the critical step. This step can be executed by past accidents analysis (PAA) to achieve the mentioned objectives. Despite of available analyses, the recurring of accidents identifies the shortcomings in PAA and requires a detailed examination as reported in this review. The intensified exploration of accident information will strengthen both the safety management system at existing facilities and process designing in terms of sustainability. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

A 3-D two-fluid CFD model in the Eulerian-Eulerian framework was developed to predict the hydrodynamics and heat and mass transfer of sieve trays. Interaction between the two phases occurs via interphase momentum and heat and mass transfer. The tray geometries are ...

Absorption of SO2, diluted with nitrogen up to concentrations of 500 Pa, was performed at 20 °C and 1 atm, with water and sulfuric acid solutions containing hydrogen peroxide in two different contactors: a packed column and a cable scrubber. The absorption rate was determined for various SO2 partial pressures, as well as different concentrations of sulfuric acid (up to 40 wt %) and of hydrogen peroxide in the scrubbing liquid. It was found that the SO2 absorption rate increases with the hydrogen peroxide concentration, and decreases as the acidity of the scrubbing liquid increases. Taking into account hydrodynamic and mass transfer characteristics of the packing for both scrubbers, a practical enhancement factor depending on the liquid phase H2SO4 and H2O2 contents, was deduced from semi-continuous tests. As a good concordance was observed between results determined for both contactors, a single correlation is proposed, allowing the computation of this kinetic factor for quite simple simulation or design of SO2 scrubbers, provided the gas and liquid phase mass transfer coefficients kGa and kLa are known.

The calcium carbonate precipitation in a single feed semi-batch precipitator has been
investigated, aiming a kinetic analysis of the process. The feed rate, concentration of
reactants and the feed location point influence the particle size distribution (PSD) as well as
kinetic parameters. The values of the transient kinetic parameters suggest a nucleation process
accompanied by the dissolution and recrystallization of the CaCO3 polymorphs.

The chemical process involves the once through precipitation of adsorbing compounds from the low solubility classes of phosphates and hydroxides, accompanied by the total chromium adsorption and bonding.

The approach subsumes the addition of phosphate ions as phosphoric acid into waste water to induce Cr3+ ion complexation, as well as the significant growth in chromium phosphate super saturation of liquid phase before mass precipitation of the adsorbents.

From the distribution of the ionic molar concentrations between liquid phase and precipitated phase, ionic balance, solubility products and literature data, there was figured out formulas of the hypothetical precipitated compounds.
Chromium and aluminium are completely removed from chromate solutions completely and found integrally in the solid phase as Cr(OH)3, Cr(OH)2Cl, Cr(OH)Cl2, CrPO4, AlPO4  and Al(OH)3.

The PO43- ion is just partially precipitated as calcium, magnesium and aluminum insoluble phosphates. Thus, the lowest concentration of PO43- ion in the mother liquors has to be considered as a criterion in appoint the best reactant combination and the appropriate reaction pH.

It was demonstrated the advanced chromium removal from tannery is possible and the resulted precipitated material could be easily converted to a safe disposable waste.

Lucrarea prezintă evoluţia principalilor poluanţi evacuaţi din halda - mal stâng de
zgură şi cenuşă de la termocentrala Işalniţa pentru o perioadă de 8 ani. Se evidenţiază
fluxurile de ape descărcate din acest tip de haldă şi se prezintă valoarea indicatorilor
specifici şi impactul asupra receptorului.

The layered sodium silicates are valuable co-builders minded to substitute tripolyphosphates
in detergent formulations. The sodium disilicate polymorphs are fairly characterized, but the
recrystallization procedures of the metastable phases from the amorphous are not well known.
Some attempts to obtain a single enriched ,  or  phase have been carried out . The
properties of these materials related to their use as builders have been evaluated.
As a result of the ecological pressure, many detergent manufacturers started incentiving
researches to find suitable alternatives for tripolyphosphates, which are main responsible for
the so called “eutrophication” process. A wide range of sodium silicates , with general
formula (Na2O)x(SiO2)y(H2O)z , have already been tested and developed to full commercial
scale as multifunctional builders [14].All these products perform the following functions in
detergency: soften the water, provide alkalinity, suspend the soil and buffer the washing
liquors, adsorb surfactants onto the particle porous surface, stabilize the bleaching agents, do
not cake and support any kind of processing. Beyond the optimal detergency, crystalline
silicates bring about less pollution and environmental friendliness