Control of Drying Process in Mechanically Spouted Bed Dryer

ABSTRACT

The continuously operated Mechanically Spouted Bed (MSB) dryer of high evaporative capacity can be advantageously used to produce fine powder from paste-like materials, slurries, suspensions and sludges. Due to the thin layer formed on the surface of the spherical inert particles intensive heat and mass transfer occur and the drying process takes place in the constant rate period. Steady state drying conditions can be achieved when the total operational time of partial processes of inert bed drying does not exceed the cycle time of the inert particles.

A laboratory scale MSB dryer has been equipped with a computerised measuring, data acquisition and control system. In the knowledge of the hydrodynamic characteristics of the MSB and giving the enthalpy and mass balances over the dryer a calculation method has been developed for control of drying process.     

Lean NOx Trap Chemistry Under Lean-Gasoline Exhaust Conditions: Impact of High NOx Concentrations and High Temperature

The primary technical barrier to deployment of fuel saving lean gasoline engines is NOx emissions control. We conducted automated flow reactor experiments on a commercial LNT catalyst to identify opportunities and challenges associated with the higher temperatures and higher NOx concentrations expected in lean gasoline applications. Overall NOx conversion was quite high at low to moderate temperatures, but dropped off at high temperatures. The decrease in NOx conversion with temperature was worse for higher inlet NOx concentrations. As expected from equilibrium considerations, the catalyst stored more NOx under higher gas phase NOx concentrations, but that NOx was rapidly released during the rich phase and slipped out of the catalyst before it could be converted to N₂ by incoming reductant. This rich phase NOx release was the primary factor limiting performance of the catalyst at high temperatures, and resulted in significant spikes of NOx that would likely exceed any not-to-exceed regulated emissions levels. N₂O production was also significant, and increased with NOx concentration. The catalyst made very little NH₃ at high temperatures. NH₃ yield was significant at the lowest operating temperature studied, but it decreased with increasing NOx concentration.     

Analysis of Polycyclic Aromatic Compounds Using Microbore Columns

The gas chromatographic analysis of polycyclic aromatic compounds can be completed faster and with increased chromatographic resolution using microbore columns (Fast GC). Microbore columns contain two to three times the number of theoretical plates per meter when compared to 0.25 mm internal diameter (i.d.) capillary columns. The increased chromatographic resolving power of microbore columns enables separations to be carried out with much shorter columns giving rise to faster analysis times. Analysis times of priority polycyclic aromatic hydrocarbons on 20 m (5% phenyl, 0.1 mm i.d., 0.1 w m film thickness) and 10 m (5% phenyl, 0.1 mm i.d., 0.1 w m film thickness) columns are reduced by about 45% and 60% respectively in comparison with 30 m columns, and data quality (precision and accuracy) is not affected. All areas/parameters of the chromatographic system must be adjusted and optimized to ensure proper chromatographic performance. Smaller injection volumes (0.2-0.5 w L) and injection liners (1-2 mm i.d.) are required to obtain optimum (and reproducible) chromatography on 0.1 mm i.d. columns.     

Synthesis and Mutagenic Activity of Bay-Region Bridged Chrysenes

The synthesis of a series of substituted bay-region bridged chrysene derivatives is described. The method involves the oxidative photocyclization of stilbene carboxylic acids followed by dehydration with hydrofluoric acid. The photocyclization of stilbene carboxylic acids lead to secondary photolactonizations and functionalization of a bay region carbon by a novel photolytic process. The mutagenic activity of the substituted chrysenes was determined and activity levels correlated with substituent effects.     

SHS in mechanoactivated Ni-Al-W blends: Some structural aspects

SHS reaction in mechanically activated Ni-Al-W blends was explored with special emphasis of structural aspects. Dry mechanical activation combined with a wet one was found to improve the strength characteristics of SHS-produced NiAl:W composite by the mechanism of dispersion strengthening.     

Extraction of phenols from industrial mixtures: A review

Research on the extraction of phenols from industrial mixtures by physicochemical methods is considered.     

Using slurries from flotational coal enrichment in the production of heat insulation on the basis of intershale clay

Heat insulation may be produced from intershale clay and slurries obtained in flotational coal enrichment, without employing traditional materials. The thermal conductivity and density of the insulation produced are 0.20 W/(m °C) and 1200 kg/m³.     

Determining the degree of coal oxidation at PAO AKKhZ

Methods of assessing coal oxidation are compared. The method developed by the Soviet Institute of Mining and the Coal Chemistry Institute is most expedient. On that basis, a draft of the Ukrainian DSTU standard on determining the oxidation of coal has been formulated. The method has been successfully used in selecting the flotation agent for coal enrichment at PAO Avdeevskii Koksokhimicheskii Zavod (AKKhZ).     

Sulfolane and dimethyl sulfoxide as extractants

The use of sulfolane and dimethyl sulfoxide in liquid extraction and extractive rectification is considered.     

Improving solid-fuel pyrolysis and gasification for effective cogeneration

The thermal conversion of solid fuel is considered (for the example of biomass), with assessment of the yield of volatiles and coke residue. The optimal temperature range for its pyrolysis (the range corresponding to maximum heat of combustion of the gases per unit mass of the initial product) is identified. The influence of steam and air flow rates on the gasification products is studied. A system for the generation of thermal and electrical energy in the steam-gas cycle is proposed, with a biomass gasification unit. The energy loads of a population center are calculated, with engineering and economic assessment of the steam-gas cycle. Biomass-based cycles are compared, from the perspective of the energy efficiency of a cogeneration system.