Decrease Sucrose Loss through Blackstrap

• Autor(a) principal: Martins, Alexandra Sofia da Silva
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Texto Completo: http://hdl.handle.net/10362/89167
• topic: Sucrose; Chemical Losses; Boiling pan; Centrifuges; Inverts; Ashes; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

´To reduce the chemical inversion of sucrose, and consequently increase the profit margin, many refineries are trying to optimise their production process by focusing on the areas most prone to losses. A Pareto diagram is developed every fiscal year to help understand the areas that have a higher contribution to this problem. In the year FY18 (October of 2017 to October of 2018) it was realised that recovery represented about 16% of the total chemical losses. Thus, before making any alterations, the different boiling pans had to be characterised, as well as its inlet and outlet streams and respective centrifuges. Since there was no time to define all of them, the present work focused on the A1 and A pans. After setting these parameters, improvements to the crystallisation profiles were proposed. Through the alteration of the absolute pressure, temperature, Brix, and tons of fed syrup, some positive changes could be observed. Using Hypothesis Tests, one for each boiling pan, the new invert generation was deter-mined with a confidence level of 90%. In A1 there was an invert reduction of 3.32 percentual points (from 8.62% to 5.30%), while for A 3.27 (from 6.31% to 3.04%). By analysing the control chart of the final molasses of recovery, it was proved that this decrease occurred and it was 0.02%. Monetarily, this value corresponds approximately to the estimated profit projection for the new invert generation. One of the goals of this thesis was also to increase the process yield. However, this value has not changed. Lastly, the centrifuges wash time was optimised, with the assistance of Design of Experi-ments (DOE). Thus, through some tests, it was possible to determine the optimal wash time to reduce the presence of ash and invert in the purged sugar. When separated from the syrup, this sugar returns into the process. In the A1 centrifugal, by applying an eight seconds wash, there was a reduction in inverts and ashes of -36.59% and -35.84%, respectively. As for the A centrif-ugal, a first wash of six seconds, followed by one of ten seconds, reduced the inverts by -62.58% and the ashes by -61.65%.