Radiation-directed production of chemical reagents and petroleum additives from waste organic feedstocks

Plant, Arran and Joyce, Malcolm and Najdanovic, Vesna (2023) Radiation-directed production of chemical reagents and petroleum additives from waste organic feedstocks. PhD thesis, Lancaster University.

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Abstract

Nuclear cogeneration is the collation of co-processes that aims to improve the sustainability, overall efficiency, and profitability of nuclear power by producing alternative products alongside electricity. A range of existing cogeneration processes explores the use of waste stream process heat for a variety of processes including district heating and desalination. However, the direct application of under-utilized ionization energy has yet to be fully realized. This thesis is a study on the potential application of ionizing radiation from nuclear facilities towards the radiolytic production of organic chemicals derived from waste renewable feedstocks. Here we show that glycerol, a notable waste feedstock from biodiesel production can be converted into acetol (hydroxyacetone) or solketal which are textile and biofuel additives, respectively using ionizing radiation from a 250-kW research fission reactor. The radical-initiated chain reaction for hydroxyl acetone (acetol) production is optimised to produce the highest G value (2.7 ± 0.4 µmol J−1) and mass productivity (~1 %) to be reported in the available radiolysis literature. A previously unreported radiolytic product, solketal, which is a valuable biofuel additive is produced radiolytically using ternary glycerol, acetone, and water mixtures with G-values of 1.5 ± 0.2 µmol J−1 at 50 kGy. Empirical data showed a preference for low LET, low dose rate, γ-ray emissions such as those from spent fuel was found to be favourable for acetol and solketal production. Simulating three production scenarios with MCNP models for preferential solketal production found that a spent fuel facility consisting of ~1710 elements showed the largest production capacity at 57.4 ± 5.6 t year−1 due to the high volume available to be irradiated. Extrapolating to a theoretical European production network involving ~180 equivalent SFP facilities based on relative reactor power, a total of (1.3 ± 0.1) × 104 t year−1 of solketal could be produced, contributing to (2.5 ± 0.2) × 108 litres year−1 to a (95% petroleum, 5% solketal) fuel blend. While this represents only ~0.3 % of total transport fuels consumed within the EU, it presents a pioneering process that could be feasible if G-values and mass productivities were improved upon.