Experiments with high pressure dewatering of manure from 5 biogas plants and fresh pig and cow manure
The purpose of this work is to develop a dewatering method that can dewater digested manure to a dry matter content that makes it possible to utilise the dry matter for energy production.
The purpose of the project is to obtain information on dewatering of manure at high pressure. This should result in the fact that the dry matter fraction of the manure can be dewatered to 55-65% dry matter and be interesting from an energy point of view. Thomas Koch Energi have developed an automatic dewaterer that can dewater manure up to 60% dry matter by means of pressures up to 400 bar. Laboratory experiment have shown that dry matter content of up to 70% is possible. The project will try' to gain information about the following: 1) Can the parameters that influence the dry matter content be identified? 2) Which factors influence the stability of and permeability of the manure? 3) Which barriers are there for removal of water? The end product will be optimised from an energy point of view. The project will consist of experiments on 3-5 biogas plants and experiments with fresh manure. During the experiment the relevant parameters will be measured on site and samples will be sent to a analysis laboratory
The report includes a compressive test on existing analysis methods for sludge. None of the methods have shown any acceptable correlation's between the results and obtained dewatering characteristics. This project have not developed any analysis methods that can predict the mechanical behaviour of manure. But the dewatering device that has been developed works, and can dewater manure. It has been proved that it is possible to dewater digested manure up to 59-60% dry matter content in laboratory conditions. (Dewatering time 10-20 minutes and a pressure of up to 61 MPa). It is possible to separate 20-30% of the dry matter in the manure in the dry fraction. This fraction contains 30-45% of the carbon in the manure. The experiment has shown that the maximum obtainable pressure in the manure (before it escapes the dewatering chamber) is dependent of the speed of pressure increase. At more 'commercial' conditions (a total dewatering cycle time of 30-60 seconds) it is possible to obtain a dry matter content of 50-54%. Some times it is possible to obtain 58% dry matter content and 2 days later it is only possible to obtain 51% dry matter content. 2-10% of the ammonium and potassium and 20-40% of the phosphorous is fund in the dry fraction. Fresh manure have been dewatered and the maximum obtainable dry matter content is approx. 25-35% at 5-15 MPa
Key figures
Category
Participants
| Partner | Subsidy | Auto financing |
|---|---|---|
| Aalborg Universitet (Fredrik Bajers Vej) | ||
| DB lab. | ||
| KRÜGER A/S |
Contact
Stationsvej 4
DK-4621 Gadstrup, Denmark
Roer Pedersen, Jan ; Projektleder: Koch, Thomas , 46191554, tke@cybernet.dk
Øvr. Partnere: Aalborg Universitet. Institut for Vand, Jord og Miljø; DB lab.; Krüger A/S
