The micro-bubble generation and destruction coefficients i.e. K_g and K_d were assume constant; this assumption is not so far from the reality . Mechanism of the micro-bubble generation depends on the liquid and gas interstitial velocities; micro-bubble fluid apparent viscosity and the bubble density, this is a known concept from the literature, but here, we can see that, bubble density controls the micro-bubble yield stress. A typical saturation and bubble density profiles are shown in the Figure 1. It shows that the micro-bubble fluid front, flows with constant speed.
Diffusion of the products from the interior of the particle to the pore mouth at the external surface 7. Mass transfer of the products from the external particle surface back to the oil The overall rate of the reaction is determined by the rate of the slowest step. When steps 1-2 and 6-7 (diffusion) are significantly faster compared to steps 3-4-5 (reaction) the reaction itself is limiting the overall rate and mass transfer will not affect the effectiveness of the catalyst. When the reaction steps are significantly faster compared to the diffusion steps mass transfer does affect the overall rate of the reaction, which is mostly the case in porous catalysts used for hydro-treating. To determine the overall reaction rate an n-order formula is used which contains the relation between the starting concentration of sulfur in the oil and the concentration of sulfur at a certain residence time in the reactor.
Literature survey on S-shaped diffusers reveals that the flow at the exit plane of diffusers is not uniform and hence offers an uneven impact loading to the design point of view, it is undesirable. Here, an attempt is made to uniform the flow of the S-diffuser, especially at its exit by changing its corner shapes (i.e. sharp 90º, 45ºchamfered etc.) as well as using submerged vortex generators (VG). Lin(7) conducted an exploratory study of such VG devices to control turbulent flow separation.
As the rarefaction and shock waves continue to travel in opposite directions, they eventually encounter the ends of the shock tube. In this case, since the left end of the tube is much closer to the diaphragm than it is to the right end, the rarefaction wave reaches its end first. In figure 1c, the rarefaction has reflected off the left end of the tube and begun moving towards the right, leaving behind a region of low pressure, P6. In figure 1d, the shock wave eventually reaches and reflects off the right end of the tube and begins moving left, leaving behind a region (5) with a higher pressure, P5, which is given by equation 6. P_5=P_2 [2γ_1 M_r1^2-(γ_1-1)]/(γ_1+1 )  In equation 4, Mr is the Mach number of the reflected shock wave, and can be determined by solving equations 7 and 8. u_p=(2a_1)/(γ_1+1) (M_s1-1/M_s1 ) =(2a_2)/(γ_1+1) (M_r1-1/M_r1
Bernoulli’s theorem is a special application of the laws of motion and energy. The principle equation describes the pressure measured at any point in a fluid, which can be a gas or a liquid, to the density and the velocity of the specified flow. The theorem can be explained by the means of imagining a particle in a cylindrical pipe. If the pressure on both sides of the particle in the pipe is equal, the particle will be stationary and in equilibrium. By implementing the second law of motion the particle will accelerate or decelerate if there exists a pressure difference over the particle.
2.1.4 Acoustic Doppler Velocimeter (ADV) Acoustic Doppler Velocimeter (ADV) is similar in operation to Acoustic Doppler current profiler (ADCP) which is based on Doppler’s shift in sound frequency. It is an emerging technique of measuring instantaneous velocity at a single point with more accuracy the ADCP as it uses the converging beam pattern and sample small amount of water. It facilitates the multiple point velocity at a single point and across the stream. 2.2 Review of Literature Chiu et al. (2005) developed a novel velocity distribution equation based on the probability concept for converting small numbers of velocity samples into mean stream velocity which can be used for estimating discharge quickly and efficiently.
INTRODUCTION The concept of chemical equilibrium was developed after Berthollet (1803) found that some chemical reactions are reversible. For any reaction mixture to exist at equilibrium, the rates of the forward and backward (reverse) reactions are equal. In the following chemical equation with arrows pointing both ways to indicate equilibrium, A and B are reactant chemical species, S and T are product species, and α, β, σ, and τ are the stoichiometric coefficients of the respective reactants and products: α A + β B ⇌ σ S + τ T The equilibrium concentration position of a reaction is said to lie "far to the right" if, at equilibrium, nearly all the reactants are consumed. Conversely the equilibrium position is said to be "far to the left"
Question#1: What is distillation? Answer: “A separation technique in which two or more substances are separated into their components from their mixture (liquid or vapour mixture) by the means of heat removal or heat addition is called distillation1.” In liquid mixture distillation, the mixture is heated and less boiling point liquid began to evaporate. Vapors of that liquid then condensed to get purified liquid. Purified liquid is then called condensate. Repetition of distillation on collected liquid is called double distillation, this can be done just to enhance the purity of collected liquid2.
Disadvantage of this column is liquid hydrostatic head caused high pressure drop. Gas and Liquid flow rate As stated by McCabe et al. (2005), the first task in designing absorption control system is to determine the flow rates and composition of each stream entering the column. From the law of conservation of mass, any material entering a process must either accumulate or exit, or in simple word, whatever comes in must go out. By using material balance, the flow rates and its composition can be determined.
The activation energy was calculated from the slope (Ea/RT) by linear plot of ln k on l/T, using the Arrhenius equation k = ln A- Ea/RT, where k is rate constant of the reaction at temperature T (in Kelvin), A is a constant and R is the universal gas constant. The catalytic reduction of 4-NP was studied at six different temperatures (25, 30, 35, 45, 55, 65 and 70oC) using olibanum gum capped AuNPs as catalyst. A linear relationship was found between ln k and the reciprocal temperature from which the activation energy was measured. A plot of ln k versus 1/T, shown in Figure. 10, is a linear curve for 4-NP reduction using AuNPs.