Optimal Design of Solvent Blend and Its Application in Coking Wastewater Treatment Process

Abstract

One of the key steps of coking wastewater treatment is phenolic and tar removal via extraction. However, the high loss of the extractant, i.e., methyl isobutyl ketone (MIBK), leads to the high cost of the process. The adoption of a novel solvent or solvent blend is considered as an efficient way to address this problem. In this paper, seven solvents (benzene, toluene, m-xylene, ethylbenzene, 1, 3, 5-trimethylbenze, cyclohexane, and octanol), selected as candidate diluters for MIBK according to operating requirements, are studied with a nonlinear programming (NLP) model based on ideal counter-current extraction. The results, verified with experiments, suggest toluene is the most promising candidate. Further investigation of this solvent blend reveals that both D blend (the distribution coefficient of phenol between solvent blend and water) and m MIBK (the MIBK concentration in raffinate) increase with x MIBK (the molar fraction of MIBK in blend). The trade-off between the extraction performance and MIBK loss recommends the blend with x MIBK = 0.05 as extractant for coking wastewater treatment. An industrial process consisting of extraction, back stripping, distillation, and mixer is presented. A corresponding NLP model is established for its operating optimization. To improve the accuracy, the representatives of typical phenolics and tar in wastewater (2,4 dimethyl phenol, m-xylene, and quinolone) are also considered in addition to phenol. The case study indicates that the blend exhibits economic advantage over pure MIBK with a makeup cost of 11.15 ¥/t, much less than the 185.15 ¥/t in the case of MIBK.

Structural Characteristic Integrated Computer-Aided Molecular Design for Phenols Removal Considering Synergistic Effect

“…9,10 Many efforts have been made to select better solvent mixtures for extracting phenols. Liao et al 11 proposed a new solvent mixture with molar fraction of 95% toluene and 5% MIBK for extracting phenols. However, this solvent mixture was likely to perform less efficiently due to the unequal proportions.…”

“…Solvent mixtures in which two solvents have a synergistic effect would perform with higher efficiency than single solvent, and are considered an efficient way to improve efficiency. , Many efforts have been made to select better solvent mixtures for extracting phenols. Liao et al proposed a new solvent mixture with molar fraction of 95% toluene and 5% MIBK for extracting phenols. However, this solvent mixture was likely to perform less efficiently due to the unequal proportions.…”

Multi-layer and open three-dimensionally ordered macroporous TiO2–ZrO2 composite: diversified design and the comparison of multiple mode photocatalytic performance

“…Pollutants such as naphthalene, anthracene and phenolic azo dyes, which are highly toxic and have poor biodegradability, were directly discharged into the environment in high concentrations, which may cause serious pollution problems for water resources [1][2][3]. Various methods have been tried for reducing water pollution [4][5][6]. Of all the wastewater treatment methods, semiconductor photocatalysis technology had been demonstrated to be the most promising prospect [7][8][9][10].…”

Efluentes de indústrias bioquímico-farmacêuticas: tratamento e redução da geração

“…A viabilidade técnica e econômica do processo por extração líquido-líquido depende prioritariamente da seleção e disponibilidade de um solvente puro MACKAY, 1971MACKAY, e 1973GREMINGER et al, 1982;CARVALHO, 2005;CORREIA et al, 2007;CHASIB, 2013;LIU et L., 2013;ABBASSIAN et al, 2015;OTHMAN et al, 2017) ou misto MACKAY, 1975;MEDIR et al, 1985;LIAO et al, 2014) com propriedades físico-químicas e logísticas adequadas (Hampe, 1986;Frank et al, 2008).…”

“…Na primeira o fenol era extraído do solvente com uma solução aquosa de NaOH, gerando fenolato de sódio insolúvel no solvente. Esta reação pode ser considerada irreversível e instantânea(ZHA et al, 1994):Esta reação é muito importante e utilizada na recuperação de fenóis de efluentes(LIU et al, 2013;LIAO et al, 2014; ABBASSIAM et al, 2015;OTHMAN et al, 2017).…”