Modelling examples of sugar crystallization - Beet/Refinery energy balances:

Modelling of continuous vertical crystallizer R1-VKT at two different seed magma ratio

Modelling of vertical continuous sugar crystallizer like R1-VKT at the same residence time (2.79 h), operating vacuum (0.2 bar abs), and MA (0.7mm) using two different seed magma ratio (25 and 10% massecuite mass).

Simulation results showing that, running continuous sugar crystallizers like VKT and CVP at lower seed magma ratio allow achievement of the optimum efficiency (the highest throughput& crystallization rate and the lowest energy consumption) of the sugar crystallizer with the use of low percentage of seed magma which is summarized in the following:

1) Crystallizer throughput increases from 137.18 Ton massecuite/h at 25% seed magma ratio to 154.23 Ton massecuite/h at 10% seed magma ratio.

2) Crystallization rate increases from 58.79 T/h at 25% seed magma ratio to 79.14 T/h at 10% seed magma ratio.

3) Crystal growth rate increases from 0.96 g/m2.min at 25% seed magma ratio to 1.39 g/m2.min at 10% seed magma ratio.

4) Feed liquor consumption increases from 122.7 T/h at 25% seed magma ratio to 165.2 T/h at 10% seed magma ratio.

5) Steam consumption decreases from 0.354-ton steam /ton sugar at 25% seed magma ratio to 0.347-ton steam/ton sugar at 10% seed magma ratio. Steam consumption is related to the deposited sugar's quantity on the original seed magma crystals (crystallization rate). 

Seed magma of small MA 300:350 microns could be used from two sources; well washed centrifuged sugar magma of low-grade strikes or boiled strikes of the same feed liquor in a separate seed vacuum pans under controlled sugar boiling conditions with use of large number of sugar crystal nuclei.

Use of high seed magma percentage is a kind of sugar recycling where 30% of capacity (working volume) of the continuous sugar crystallizer is reduced in such cases.  

OZsugar integrated control software program for batch sugar crystallization with features of online monitoring and control of all sugar crystallization controlling's parameters.

Sugar crystallization case: Refined sugar grade1 (R1) sugar crystallization cycles at two operating vacuum conditions 0.2 and 0.1 bar abs. The whole crystallization cycle from establishing vacuum, material's charging to discharging of the obtained massecuite is performed and controlled in auto sequence steps by the program. The tracking and control of all controlling parameters such as supersaturation coefficient SS, crystal content CC, mother liquor brix & purity, mean aperture MA, and crystallization rate through the real detection of boiling point elevation or mother liquor brix.

Implementation of OZsugar controlling software program on batch vacuum pans of refined sugar in a large cane sugar refinery soon.

Simulation of the two R1 cycles showing that, R1 batch sugar crystallization cycle running under low vacuum pressure 0.1 bar abs achieves 8.9% energy saving per cycle, working with lower temperature difference (steam to vapor), and use low-pressure vapors of less color formation than working under higher vacuum pressure 0.2 bar abs. 

Flash cooling crystallization or continuous vacuum cooling (CVC) is essential in beet sugar processing and cane sugar refining operations. This technique plays a crucial role as supplementary sugar boiling after the main process in batch pans or continuous pans like CVP or VKT.

By operating under deep vacuum conditions, CVC enables the necessary temperature variance for flash evaporation from massecuite and recirculating run offs, maximizing sucrose extraction and enhancing the sugar yield of the strike. Post-CVC, the crystal growth in the massecuite can increase by 10 to 25% of the original mass, depending on its grade and quality.

Moreover, the implementation of CVC results in a reduction in the number of sugar boilings required, leading to decreased steam consumption in both cane sugar refining and beet sugar processing. This efficient cooling and crystallization method not only improves sugar yield but also optimizes the overall production process.