Feasibility of an integrated biogas scrubber for a swine manure digester
North, John Robert
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/20837
Description
Title
Feasibility of an integrated biogas scrubber for a swine manure digester
Author(s)
North, John Robert
Issue Date
1990
Doctoral Committee Chair(s)
Day, Donald L.
Department of Study
Agricultural and Biological Engineering
Discipline
Agricultural Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Engineering, Agricultural
Engineering, Chemical
Engineering, Sanitary and Municipal
Language
eng
Abstract
Laboratory experiments were conducted to study a scrubbing system for the removal of carbon dioxide (CO$\sb2$) from the biogas produced by a swine manure anaerobic digester. This innovative scrubbing system was included in the original design of an existing full-scale digester, but had never been tested. The principle of operation was that ammonia (NH$\sb3$) gas would be desorbed from the influent manure in an enclosed preheating vessel, the mix tank, and subsequently reabsorbed in a separate scrub tank full of water (charging cycle). The biogas was passed through this charged scrubbing solution (scrubbing cycle). The CO$\sb2$ would then be absorbed from the biogas stream, producing a higher quality gas in terms of methane content.
Scale models of the full-scale system were constructed and operated in the lab. The critical parameters studied were the pH of the manure slurry in the mix tank, the frequency of operation of the charging cycle, and the rate of turnover of the scrubbing solution. The objectives of this study were to determine the effect of the variation of these parameters on the efficiency of the scrubbing process, and to assess the physical and economic feasibility of incorporating any beneficial modifications into the full-scale system.
The experimental results showed that the scrubbing mechanism described above did not work. Minimal amounts of NH$\sb3$ were transferred from the manure to the scrubbing solution. However, significant CO$\sb2$ removals were achieved via a different mechanism. The charging cycle transferred the biogas (and CO$\sb2$) from the scrub tank to the mix tank, where it was absorbed into the manure. The scrubbing efficiency was directly proportional to the manure pH and the charging cycle frequency. The maximum CO$\sb2$ removal was about 77% corresponding to an average mix tank pH of about 9 and a charging cycle frequency of 4 cycles per hour.
It was determined that this scrubbing process would not be feasible for this application, due to the large quantities, and costs, of alkali required to maintain the manure pH at a beneficial level.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
