A Comparison of Distillery Stillage Disposal Methods

This paper compares the main stillage disposal methods from the point of view of technology, economics and energetics. Attention is paid to the disposal of both solid and liquid phase. Specifically, the following methods are considered: a) livestock feeding, b) combustion of granulated stillages, c) fertilizer production, d) anaerobic digestion with biogas production and e) chemical pretreatment and subsequent secondary treatment. Other disposal techniques mentioned in the literature (electrofenton reaction, electrocoagulation and reverse osmosis) have not been considered, due to their high costs and technological requirements.Energy and economic calculations were carried out for a planned production of 120 m3 of stillage per day in a given distillery. Only specific treatment operating costs (per 1 m3 of stillage) were compared, including operational costs for energy, transport and chemicals. These values were determined for January 31st, 2009. Resulting sequence of cost effectiveness: 1. – chemical pretreatment, 2. – combustion of granulated stillage, 3. – transportation of stillage to a biogas station, 4. – fertilizer production, 5. – livestock feeding. This study found that chemical pretreatment of stillage with secondary treatment (a method developed at the Department of Process Engineering, CTU) was more suitable than the other methods. Also, there are some important technical advantages. Using this method, the total operating costs are approximately 1 150 ??/day, i.e. about 9,5 ??/m3 of stillage. The price of chemicals is the most important item in these costs, representing about 85 % of the total operating costs

Image analysis in an agitated particle - liquid transparent system

Large tall vessels with a draught tube are used for the mixing of suspensions especially in cases where high homogeneity and heat tranfer are desirable. The article describes flow behaviour of liquid in the vessel with a draught tube. LDA method (Laser Doppler Anemometry) was used for measurement axial velocity profile. The experimental configuration for LDA method was produced by firm DANTEC. Experimental results are compared with numerical simulation and other experiment

Pumping capacity and local energy dissipation rate at mixing of low concentrated suspension

Present work is taking in account all corrections respecting the properties of additional optical system for perfection of all presiously published velocity data. From the velocity components in all the three directions impeller pumping capacity and energy dissipation rates are calculated

Wpływ dawki flokulantu na kinetykę flokulacji zawiesiny gliny o stężeniu 0,78 g/l w mieszalniku przy intensywności mieszania 168 W/m3

Effect of flocculant dosage on clay slurry flocculation was investigated a baffled tank agitated by the Rushton turbine at mixing intensity 168 W/r and clay concentration 0.78 g/1. The model wastewater was flocculated wi organic flocculant Sokoflok 16A (solution 0.1 wt %). Created flocks we separated by sedimentation. The maximum turbidity removal degree equ to 98% was observed experimentally at flocculation time 10 min and t] dosage 2 ml/1. The generalized correlation proposed by Śulc and Dili (200 was used for data treatment. The correlation predicts maximum turbidity i moval degree 98.3% for flocculation time 7 min and the dosage 2.176 mlBadano wpływ dawki fiokulantu na proces flokulacji zawiesiny gliny w mieszalniku z przegrodami wyposażonym w turbinę Rushtona przy intensywności mieszania 168 W/m3 i stężeniu gliny 0,78 g/l. Modelowa zawiesina agregowała pod wpływem fiokulantu organicznego Sokoflok 16A (roztwór 0,1 wt %). Powstałe flokuły oddzielano za pomocą sedymentacji. Najwyższy stopień usunięcia mętności równy 98% obserwowano po czasie flokulacji 10 min i dawce 2 ml/l. Przy opracowaniu wyników wykorzystano uogólnioną zależność zaproponowaną przez Sulca i Ditla (2008). Zależność ta przewidywała najwyższy stopień usunięcia mętności równy 98,3% dla czasu flokulacji 7 min i dawki 2,176 ml/l

Progress in the evaluation of local energy dissipation rate in an agitated vessel

The scale-up of processes such as liquid-liquid dispersion, gas-liquid dispersion, powder dispersion, flocculation, the scale of segregation at chemical reactions requires correct knowledge of local turbulent energy dissipation rate. This paper presents progress in the evaluation of local dissipation rate in an agitated vessel. The effect of PIV spatial resolution on velocity field in the impeller discharge flow is discussed

Numerical Simulation of Multicomponent Isobaric Adsorption in Fixed Bed Columns

A model has been formulated for multicomponent isobaric adsorption in fixed bed columns. The following mass transfer mechanisms were used: convective flow, axial dispersion, external particle mass transfer and intraparticle diffusion. Analysis was applied on the system of governing equations to obtain controlling dimensionless criteria for the fixed bed adsorber. The derived criteria can be divided into three groups, namely: main dynamic criteria, equilibrium criteria and multicomponent dynamic criteria, their physical meaning has been discussed. The system of equations has been numerically solved using a finite difference method with an implicit conservative scheme. On the basis of this model a numerical simulation has been made to determine the influence of external particle mass transfer, axial dispersion, intraparticle diffusion and adsorption equilibrium on adsorber dynamics

The effect of process conditions on the flocculation process occurring in an agitated vessel

The effect of flocculation time, flocculant dosage, pollutant concentration, mixing intensity and tank size on flocculation performance was experimentally studied in a mechanically agitated vessel. The macroscopic approach was applied for fl occulation modelling. The simple semi-empirical generalized correlation for flocculation kinetics proposed by Šulc (2003a) and the simple semi-empirical generalized correlation quantifying the effect of flocculation time and flocculant dosage on fl occulation proposed by Šulc, Ditl (2007) were used for data treatment

Porównanie metod suszenia gazu ziemnego przechowywanego w podziemnych magazynach gazu

Underground storage reservoirs are widely used. Gas is stored at 7 to 20 MPa and 20 to 35°C. Gas is saturated by moisture during the storage period. However, distributed gas should meet certain conditions. To reach requested water content the following methods can be used: absorption to triethylenglycol (TEG), adsorption by solid desiccants and multistage expansion. Energy demand, advantages and disadvantages of methods are discussed on base of chemical engineering calculations and available information.Podziemne zbiornki gazu są szeroki stosowane. Gaz przechowuje się pod ciśnieniem od 7 do 20 MPa i w temperaturze od 20 do 35°C. Podczas przechowywania gaz jest nasycony wilgocią. Jednakże rozdzielany gaz powinien spełniać określone warunki. Aby uzyskać wymaganą zawartość wilgoci w gazie można zastosować następujące metody: absorpcję glikolem trietylenowym (TEG), absorpcję stałymi substancjami osuszającymi i wielostopniową ekspansję. Zapotrzebowanie energii, zalety i wady wymienionych metod z uwzględnieniem obliczeń procesowych oraz dostępnej informacji są omówione w artykule

The effect of process conditions on the flocculation process occurring in an agitated vessel

The effect of flocculation time, flocculant dosage, pollutant concentration, mixing intensity and tank size on flocculation performance was experimentally studied in a mechanically agitated vessel. The macroscopic approach was applied for fl occulation modelling. The simple semi-empirical generalized correlation for flocculation kinetics proposed by Šulc (2003a) and the simple semi-empirical generalized correlation quantifying the effect of flocculation time and flocculant dosage on fl occulation proposed by Šulc, Ditl (2007) were used for data treatment