Effect of Process Parameters on the Progressive Freeze Concentration of Sucrose Solutions

Abstract

The progressive freeze concentration of sucrose solutions was tested. The effect of the initial concentration of the solution (C 0), the temperature of the refrigerant (T) and the stirring speed (ω) on the final concentration of the solution was determined. The effects were significant on the freeze concentration, for both individual and combined effects. The maximum concentration achieved in the progressive freeze concentration was 53º Brix, when the initial concentration was 35º Brix, at a speed of 800 rpm and a temperature of refrigerant of-20°C. The best values of the concentration index are obtained at low concentrations, high stirring speed and low temperature. The average distribution coefficient increased with the initial concentration of the solution. The average yield parameter at different initial concentrations is around 0.6 kg ice•kg sol-1 •h-1 .

Progressive freeze concentration of skimmed milk in an agitated vessel: Effect of the coolant temperature and stirring rate on process performance

“…solids concentration than the coolant temperature (À5, À10, and À15 C). Ojeda et al (2017) observed similar behavior by the concentration of sucrose solutions while using the same freeze concentration system employed in the present study. Table 1 shows the results of freeze concentration efficiency (eff).…”

“…The average ice growth rate of the tests, calculated according to Chen et al (1998), is within the interval between 1.47 and 4.02 mm s À1 . Moreno et al (2014) and Ojeda et al (2017) observed similar results during the freeze concentration of coffee and sucrose solutions, respectively. So, these average ice growth values were lower than the critical value of approximately 8 mm s À1 reported by some authors (Moreno et al, 2014;Petzold et al, 2016).…”

“…The tests were performed with experimental PFC equipment as described by Ojeda et al (2017) (Figure 1). It is comprised of a jacketed tank (1) with an inner diameter of 115 mm, 230 mm height, and 2400 mL capacity.…”

“…Thus, the highest performance and efficiency of a freezing concentration process depend strongly on finding the optimum operating conditions. Ojeda et al (2017) and Osorio et al (2018) evaluated the influence of the following operational variables in the freeze concentration process of sucrose and ethanolwater solutions: initial concentration of the solution (C i ), refrigerant temperature (T), and stirring speed (o). Yahya et al (2017) recently studied the effect of the coolant temperature and the agitation speed on a PFC system for sugarcane juice.…”

Progressive stirred freeze-concentration of ethanol-water solutions

“…In the case of tubular progressive FCs, their high efficiency and 67 ease of scaling is emphasized while in the case of vertical progressive FCs, it has been 68 possible to obtain crystals of high purity (Miyawaki, Gunathilake, et al 2016). Recently, 69 there was a report on hybrid equipment (Ojeda et al 2017), which functions as a vertical 70 progressive FC but manages to generate the ice film not only at the bottom but also on the 71 inner walls of the tank, similar to a progressive tubular FC. One of the most important 72 challenges faced by progressive FCs is in increasing the solute recovery (increased 73 separation efficiency) as ice tends to grow with impurities.…”