(221e) Optimal Integrated Plant for Renewable Surfactants Production

The sustainable development goals pose a number of challenges to the traditional industry. The sustainable production and consumption from the UN requires a complete transformation of the chemical and consumer goods industry. Chemicals traditionally produced from crude fractions must find another raw material that is renewable and alternative production routes. Surfactants are specialty chemicals whose purpose is to wet, emulsify, help solubilize or soften species. They are used in laundry as well as in other industries such as gas recovery from fracture and, so far, they have been typically produced from crude oil. Washing clothes or dishes means that sooner or later the species end up in a water body. Even if the waste water treatment plants are capable of processing and removing surfactants from water, including the two major ones such as linear alkylbenzene sulphonates (LAS) and the alkyl phenol ethoxylates (APE), that are aerobically degraded and partially absorbed to the sewage sludge, biodegradable ones can certainly help in the sustainability of products such as detergents. There are already synthetic paths for sustainable biosurfactants (Kumar et al., 2022; Reis et al 2013) In most linear processes that transform biomass into the biosurfactants are presented. Surfactants consist of two sections, a hydrophilic head group and a hydrophobic alkyl chain. Alternatively, it is possible to generate both fractions from biomass to build alkyl poluglucosides, APG’s, (Rivai et al 2017) and that can be produced from manure and CO₂.

This study presents the conceptual design for the production of sustainable surfactants from waste, including CO₂ and manure. An integrated facility is designed to process the waste employing it to grow algae and produce biogas. From the algae, intermediates such as glucose and lipids are obtained. From biogas, hydrogen is produced. Next, alcohols are produced via lipids hydrogenation so as to synthesize the APG’s from them and the glucose. No further raw material is required, at the expense of a large investment. The design problem is formulated as a large NLP for the selection of processing route of the intermediates and final product as well as the operating conditions. Such formulation allows for the selection of the algae growing and its composition for the limited use of additional utilities and chemicals. An economic analysis and process scale down has also been performed.

The algae composition recommended consists of 60% lipids and 27% carbohydrates. The yield of the facility reaches 0.47kg/kg algae (0.08kg/kg manure). For the production of 252 kt/yr of APG, the facility consumes 17.7 MW of thermal energy and steam and 7.9 MW of electricity, absorbing 788 kt/yr of CO₂ after discounting the emissions related to thermal and power consumption. The investment adds up to 196 M€ for a production cost of 0.17€/kg_APG. The large amount of manure to be processed, corresponding to 300k cows, suggests a scale down study to evaluate the effect on the investment and production costs. Current market price of APG can be achieved processing the waste of over 2.5k animals.

References

Kumar, S., Kumar Kansal, S., Pandey, A., Saravanamurugan, S. (2022) Chapter 14 - Polyalkylglycosides: sustainable production of nonionic biosurfactants from lignocellulosic biomass, 373-390. In Biomass, Biofuels, Biochemicals Biochemicals and Materials Production from Sustainable Biomass Resources (Li, H., Pandey, A., Saravanamurugan S., Elumalai S edas. Elsevier Oxford.

Reis, R.S., Pacheco, G.J., Pereira A.G. , Freire D.M.G. (2013) Biosurfactants: Production and Applications DOi: 10.5772/56144

Rivai, M., Astuti, Y., Hambali, E., Permadi, P., Suryani, A., & Sutanto, A. (2017). Selection of PTSA Catalyst Concentration for the Synthesis Alkyl Polyglycosides from Fatty Alcohol (C16) and Glucose Syrup. 11

The Joint Conference on Chemistry in conjunction with the Regional Biomaterial Scientific Meeting. Proceeding of Chemistry Conferences, Volume 2.