Optimizing bio-coagulants for brewery wastewater treatment using response surface methodology

Coag-flocculation process was used to treat brewery effluent stream with Detarium Microcarpum seed powder (DMSP) and oyster dried shell powder (ODSP) as coagulants. The proximate analyses of the coagulants were obtained using AOAC standard method. Percentage moisture, ash, fat, crude protein, crude fiber and carbohydrate content were determined for both coagulants. Jar test experiments were employed for the coag-flocculation process and response surface methodology (RSM) optimize the process. A box-Behnken design (BBD) of Design Expert 6.0.8, implementing RSM was used to evaluate the effects and interactions of three factors: coagulant dosage, pH and stirring time on the treatment efficiency. The optimal conditions obtained were coagulant dosage of 100.53mg/L, pH of 2.001 and stirring time of 24.47mins with 90.44% solid particle (SP) removal (desirability value of 1.0) and coagulant dosage of 104.19mg/L, pH of 3.34 and stirring time of 27.54 with 96.55% SP removal (desirability value of 1.0) for DMSP and ODSP, respectively. These agree reasonably with the experimental optimum for both coagulants. A determination coefficient, R2, of 97 and 98%; F-value of 45.8056 and 55.3045; and prob.-value of 1.92E-07 and 2.39E-07 for DMSP and ODSP respectively were used to evaluate the model adequacy.RSM has been demonstrated to be appropriate approach for the optimization of this process.Keywords: Coag-flocculation, Detarium Microcarpum, oyster shell, optimization, response surface methodolog

Application of process synthesis for the recovery of valuable chemicals from an industrial waste stream

MSc ThesisA dissertation submitted in partial fulfilment of the requirements for the degree Master of Science in Engineering to the Faculty of Engineering and the Built Environment, School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, 2018This work aims at designing and simulating on Aspen Plus process simulator a process that can recover valuable chemicals from a High Organic Waste (HOW) stream produced at Sasol Secunda plant, South Africa. The waste is made up of low boiling point organic components such as pyridine, acetonitrile and Methyl Ethyl Ketone and water. Currently, the waste is incinerated without energy recovery. This practice serves to exacerbate the already high greenhouse gases emissions from the plant, but more importantly, it results in the missed opportunity to maximize revenues through resale of recycled valuable chemicals. The recovery of valuable chemicals from the HOW is made difficult by the formations of azeotrope between organic components and water; at least 6 azeotropes exist in the HOW stream. In this work the emphasis is on pyridine because of its established market value and demand. Pyridine market size is about 400 million USD in 2017 and is expected to increase to over 600 million USD by 2021 mainly due to increased usage in the agrochemical industry. Water integration strategy was also assessed demand because of the reported need to improve water utilization efficiency at Sasol Secunda plant. The recovery was achieved in 2 separate steps: 1) water-pyridine mixture was separated from the rest of the HOW stream using fractional distillation and 2) pyridine enrichment section which was designed using thermodynamic tools such as residue curve maps and isovolatility curves. The rest of the HOW stream (light fractions) was sent to the currently used incinerator. Liquid-liquid extraction and azeotropic distillation were considered for the pyridine enrichment step. Results showed that the combination of liquid-liquid extraction and distillation offered the benefit of a lower entrainer to azeotropic mixture ratio (EA) compared to azeotropic distillation. This gave the lowest recorded EA at 0.320:1. The comparison between the proposed process and the incineration of the whole HOW stream showed that the implementation of the process proposed reduced the incineration load by 60wt% and CO and CO2 emissions by 50%. Dividing Wall column process integration technique was implemented to reduce the number of distillation columns in the proposed process and 10% reduction in the reboiler and condenser duties was observed. Implementation of DWC further improved the purity of the recovered pyridine from 96mol% to over 99.9mol%. Preliminary economic evaluation carried out on Aspen Plus showed that the proposed recovery process was profitable with an Internal Rate of Return (IRR) of 20% and a payback period of 4.5 years.MT 201

Isoamyl alcohol production integrated with hydrous ethanol production : otimization, heat integration and economic evaluation

Orientador: Eduardo Augusto Caldas BatistaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: O etanol produzido a partir da cana-de-açúcar constitui uma das melhores alternativas para a manufatura de biocombustíveis para o Brasil. A demanda energética e melhor aproveitamento de subprodutos são áreas com grandes potenciais de melhorias para tornar o processo de produção de etanol ainda mais rentável. O setor sucroalcooleiro brasileiro apresenta aumentos sucessivos de produção de etanol. Essa ampliação da produção de etanol permitirá usos mais rentáveis de subprodutos como o óleo fúsel, que é uma mistura de vários alcoóis tais como isobutanol, etanol, propanol e, principalmente, o álcool isoamílico. Esses alcoóis podem ser aplicados em indústrias de alimentos, de tintas e vernizes, de plastificantes e de perfumaria. No entanto, o óleo fúsel não tem sido devidamente aproveitado pelas usinas. No campo da energia, o desenvolvimento de tecnologias de destilação com maior eficiência é profícuo, uma vez que essa etapa é responsável por parte considerável dos custos de utilidades e de investimentos da produção de etanol. Diante destas circunstâncias, o presente trabalho tem como objetivo investigar processos que aumentem a economicidade e sustentabilidade da produção de etanol através da redução dos custos de utilidades e de equipamentos da destilação de etanol ou por meio da manufatura de produtos com maior valor agregado. Com a premissa de serem processos com relativa facilidade de aplicação, os seguintes processos são investigados: Produção de álcool isoamílico integrada à produção de etanol; utilização de colunas de elevada eficiência energética para separações multicomponentes (coluna com parede dividida e colunas de múltiplo efeito); otimização da demanda energética do processo convencional de destilação de etanol; destilalação de óleo fúsel para produção de etanol, álcool isoamílico e butanol. A produção de álcool isoamílico integrada à destilação de etanol permite aumentar a recuperação de etanol e produzir, a partir do óleo fúsel, uma mistura de elevada pureza de álcool isoamílico e seu isômero álcool amílico ativo. A integração energética com colunas de múltiplo efeito para o processo de produção integrada de etanol e álcool isoamílico, no entanto, não se mostrou uma alternativa viável economicamente, pois pequenas diferenças de temperatura para transferência de calor entre as colunas foram obtidas. A fim de um maior aproveitamento de outros constituintes do óleo fúsel, a configuração autônoma para recuperação de butanol, álcool isoamílico e etanol a partir do óleo fúsel apresentou elevadas purezas e recuperações desses componentes em um processo isento de solventes que emprega apenas colunas de destilação convencionais e decantadores. Outra importante contribuição desta tese é a otimização dos custos energéticos da destilação industrial de etanol em função da composição da flegma. As condições ótimas encontradas permitem uma economia na demanda de energia de cerca de 15 % em algumas usinas de etanol já em funcionamento, apenas pelo controle da composição da flegma. O processo de produção de etanol hidratado utilizando colunas com parede dividida (DWC) apresenta menores custos de utilidades (redução da demanda de energia de 21 %) e economia de investimento em equipamentos de aproximadamente 15 % comparado com o arranjo convencional da destilação industrial de etanolAbstract: Bioethanol produced from sugarcane is a great alternative to produce biofuels for Brazil. The energy demand and better utilization of by-products are areas with large potential improvements in the ethanol production process. The ethanol industry in Brazil has experienced successive increases in demand and production. This expansion of ethanol productivity will allow more profitable uses of products such as fusel oil, a mixture of various alcohols such as isobutanol, ethanol, propanol and, especially, isoamyl alcohol. Such alcohols have applications in various industries. However, current applications of fusel oil presents low economic benefits for ethanol mills. Energy demand is another point that has great impact on increasing the sustainability and profitability of bioethanol production. The development of more efficient distillation technologies is very important because this unit operation is responsible for a considerable part of the utilities and investment costs in ethanol production. Moreover, this reduction in steam consumption can increase the quantity of bagasse available to be used for bioelectricity or cellulosic ethanol production. In these circumstances, the present study aims to investigate processes that increase the economic benefit and sustainability of ethanol production by reducing utilities and equipment distillation costs or by manufacturing of products with higher added value. With the premise of having relative ease application, the following processes are investigated: integrated process for isoamyl alcohol and ethanol production; use of high energy efficiency columns distillation for multi-component separations (divided wall column and multi-effect columns; energy demand optimization of the conventional distillation process of ethanol; distillation process of fusel oil to obtain ethanol, isoamyl alcohol and butanol. The integrated production of ethanol and isoamyl alcohol allows increasing the recovery of ethanol and producing isoamyl alcohol and its isomer active amyl alcohol with high purities from fusel oil. However, energy integration using a multi-effect distillation columns for the integrated process was not an economically viable alternative due to the small temperature differentials obtained for energy transfer between columns. To make better use of other constituents of fusel oil, the investigation of an autonomous plant configuration for butanol, isoamyl alcohol and ethanol recovery from fusel oil was investigated, this process shows high recovery rates of these components by a process that does not use solvents and employs only conventional distillation columns and decanters. An additional contribution of this thesis is to demonstrate the influence of phlegm concentration on energy demand costs of industrial ethanol distillation. The optimal economic conditions allow savings in energy demand of about 15% in the current ethanol plants, only by controlling the composition of phlegm. The process of hydrated ethanol production using a Divided Wall Column (DWC) was developed and optimized. Compared with the conventional sequence of two distillation columns, the DWC proposal presented lower costs of utilities and equipmentDoutoradoEngenharia de AlimentosDoutor em Engenharia de Alimentos2013/09432-0130750/2012-3, 142031/2013-5FAPESPCNP