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Nutzbarmachung von Phosphor aus Roggenkleie - Prozessentwicklung und -bewertung
Citation Link: https://doi.org/10.15480/882.13866
Publikationstyp
Doctoral Thesis
Date Issued
2024
Sprache
German
Author(s)
Advisor
Referee
Title Granting Institution
Technische Universität Hamburg
Place of Title Granting Institution
Hamburg
Examination Date
2024-11-08
Institute
TORE-DOI
Citation
Technische Universität Hamburg (2024)
Phosphorus (P) is an essential nutrient for all forms of life and is therefore indispensable for agriculture. Fertilizers in particular make up the majority of P use in Germany, accounting for 90% of imported mineral P. However, as the deposits of mineral P are limited and non-renewable, sustainable P management is necessary for long-term availability. Large P losses occur primarily through leaching into surface waters, in wastewater treatment plants, or with slaughterhouse waste. Organic P, which is mainly present as a P reservoir in cereals and legumes, cannot be absorbed as a nutrient by animals and plants due to its binding form. Therefore, most organic P is excreted by the animals and – after deployment of the residues as an organic fertilizer – washed out into surface waters via erosion and groundwater; thus, promoting the risk of eutrophication. The aim of sustainable P management must therefore be to circulate P in the environment in as closed a manner as possible and thus also to utilize organic forms of P efficiently. In this way, on the one hand, agriculture with high land productivity and thus a sufficient food supply can be ensured and, on the other hand, eutrophication as a result of increased P application to the environment can be prevented. The present work shows a potential process with which the P organically bound as phytate in rye bran (as an example of widely used animal feed rich in P) can be made available and utilized efficiently. Within this work, a three-stage process was developed to recover phytate-P from the rye bran in a usable form as mineral phosphate salt, while the remainder of the bran is still available as a feedstuff. The process involves acid extraction of the phytate from the rye bran,
subsequent release of the phosphate from the organic bond by means of thermal hydrolysis and finally salt recovery by precipitation as magnesium phosphate. Experimentally, a total yield of phosphate in relation to the P content of the native bran of 93% was achieved in the lab. The product, a precipitate with a P content of approx. 11wt.-%, can be used for technical or agricultural applications. Based on the results in the laboratory, a theoretical process scaling shows that implementation on a larger scale is technically feasible, but that process adaptations are necessary for an economical presentation of the product. The main costs are incurred for the use of chemicals for extraction and precipitation as well as the electricity requirement, resulting in a cost of production of 34.4 € kg-1. This value is relatively robust with respect to deviations within the largest cost positions as well as investment costs, which show uncertainties in the data base. However,
some investigated feasible process modifications could have a significant impact on the product manufacturing costs with a reduction of up to 40%. Overall, full utilization of the P from the total quantity of cereal bran used as animal feed in Germany could cover around 9% of mineral P imports in Germany. If the process was extended to all feedstuffs with a yield remaining the same, the entire import volume of mineral P could be compensated for. This means that conditioning feed before it is fed has enormous potential to contribute to a sustainable P management and, thus, not only to the protection of mineral P deposits, but also to the reduction of the eutrophication problem.
subsequent release of the phosphate from the organic bond by means of thermal hydrolysis and finally salt recovery by precipitation as magnesium phosphate. Experimentally, a total yield of phosphate in relation to the P content of the native bran of 93% was achieved in the lab. The product, a precipitate with a P content of approx. 11wt.-%, can be used for technical or agricultural applications. Based on the results in the laboratory, a theoretical process scaling shows that implementation on a larger scale is technically feasible, but that process adaptations are necessary for an economical presentation of the product. The main costs are incurred for the use of chemicals for extraction and precipitation as well as the electricity requirement, resulting in a cost of production of 34.4 € kg-1. This value is relatively robust with respect to deviations within the largest cost positions as well as investment costs, which show uncertainties in the data base. However,
some investigated feasible process modifications could have a significant impact on the product manufacturing costs with a reduction of up to 40%. Overall, full utilization of the P from the total quantity of cereal bran used as animal feed in Germany could cover around 9% of mineral P imports in Germany. If the process was extended to all feedstuffs with a yield remaining the same, the entire import volume of mineral P could be compensated for. This means that conditioning feed before it is fed has enormous potential to contribute to a sustainable P management and, thus, not only to the protection of mineral P deposits, but also to the reduction of the eutrophication problem.
DDC Class
6: Technology
660: Chemistry; Chemical Engineering
660.2: Chemical Engineering
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Natalie Mayer_Dissertation_Nutzbarmachung von Phosphor aus Roggenkleie_2024.pdf
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