Evaluating environmental impacts of a solvent recovery unit in a chemical factory by using life cycle assessment


Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Çevre Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2016

Öğrenci: GİZEM HAKYEMEZ

Danışman: FİLİZ BENGÜ DİLEK

Özet:

In this study, Life Cycle Assessment (LCA) Technique was used to analyze the possible environmental impacts of the Solvent Recovery Unit (SRU) of a chemical factory. Firstly, the impact assessment of the SRU where a solvent of dimethylacetamide (DMAc) is currently being recovered by distillation, was performed using LCA with the help of SimaPro software, Eco-Indicator 99 method. Functional unit of the analysis was set as 1 kg of waste solvent recovered. Secondly, the case in which a solvent of dimethyl sulfoxide (DMSO) is used in the plant as an alternative solvent was assessed. It was found that the environmental impact of these solvents are almost compensated by their recovery. Overall total impact scores for the recovery of DMAc and DMSO in the SRU were found as 0.00457 Pt and 0.00451 Pt, respectively. Thirdly, end-of-pipe treatment and incineration were considered for both solvent types, DMAc and DMSO. Functional units were selected as 1 kg waste solvent treated and 1 kg waste solvent incinerated, respectively. In case of end-of-pipe treatment, DMAc and DMSO increased the overall impact of the baseline end-of-pipe treatment by 4,125 and 3,137 times, respectively. In case of waste solvent incineration, DMSO resulted in less impact than DMAc in all impact categories. Comparison of three solvent handling methods revealed that environmental impact of the solvent recovery by distillation is the smallest whereas the end-of-pipe treatment is the highest for both DMAc and DMSO cases. Finally, financial comparison of the solvent recovery and end-of pipe treatment handling methods indicated that solvent recovery is economically favorable option. Financial comparison was performed for DMAc case only, as the plant cost data was available only for DMAc recovery.