Abstract

This report summarises the theoretical design of a degasification plant to recover ammonia and carbon dioxide from organic residues, such as agricultural digestates, manure and municipal/industrial wastewater. Heat and water management had been identified as one crucial factor to optimise during this research. The chemical and physical parameters reveal the high tendency of ammonia towards water phase and underline the difficulty in ammonia stripping. Besides temperature, the volumetric gas-liquid ratio had been identified as most important factors. Regarding pH-value it had been observed, that a further increase is not sufficient once pH 9 is reached. Applied absolute pressure also has been identified of lower importance, compared to temperature and volumetric gas-liquid ratio. The latter three parameters are influencing evaporation and heat management in the desorption stage. A design model from literature according to Onda showed good correlation with the practical experiments including packings. Other column fillings as cones lead to operational problems. The understanding of the exact relations in column design are further used to design a cost-efficient process with low carbon footprint. The practical tests, as such, were reproducible, however the batch operation and limitations in the column design resulted in a limited transferability towards large scale plants. In terms of the absorption stage, the pilot needs to be further optimised to reach sufficient recovery rates. An absorption of ammonia and carbon dioxide under use of gypsum is favoured to also recover carbon dioxide and to avoid sulfuric acid dosing. In that term further tests and optimisation is needed, to have a fully quantifiable pilot system. The integration of a measure-control system is a further development step. In conclusion, the degasification process with low pressure (vacuum) reveals benefits compared to conventional air stripping in terms of heat management and the necessary gas-liquid-ratio, which has effects on column diameter and eventually column height. The necessity of aggressive chemicals dosage (as caustic in desorption) or acid (in absorption) is in view of the authors not given, hence cheap and safe alternatives (e.g. CO2 stripping) and gypsum dosage as alternative sulphur source work sufficient.

Abstract

As part of their communication activities, multi-actor approach projects are required to produce short “practice abstracts” (PAs) which outline their plans and main findings. The information should be easy understandable and provided throughout the project’s life-cycle. This information must therefore be shared in a specific format (the “EIP Common format”) which is specially made so that project info and results can be shared with those who can apply the findings. The format includes: a short and understandable title, a succinct summary of the issue tackled and the main outcomes and recommendations produced, and contact details to find further information. The content of the submitted practice abstracts can be updated at any moment according to new findings.

Do you want to download “{filename}” {filesize}?

In order to optimally design and continuously improve our website for you, we use cookies. By continuing to use the website, you agree to the use of cookies. For more information on cookies, please see our privacy policy.