Impedance-based moisture content sensor assessment for gas-phase biofilters

Zheng, Zhonghua

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https://hdl.handle.net/2142/95299 Copy

Description

Title

Impedance-based moisture content sensor assessment for gas-phase biofilters

Author(s)

Zheng, Zhonghua

Issue Date

2016-11-09

Director of Research (if dissertation) or Advisor (if thesis)

Wang, Xinlei

Department of Study

Engineering Administration

Discipline

Agricultural & Biological Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Gas-phase biofilter
• Impedance
• Moisture sensor
• Nitrogen compounds
• Particle size distribution

Abstract

A woodchips-based gas-phase biofilter is capable of mitigating airborne ammonia efficiently. The moisture content (MC) of the biofilter media is important to determine ammonia mitigation and nitrous oxide generation. It is critical to monitor real-time moisture content of the biofilter media for maintaining biofilter performance. The objectives of this research are to obtain a deep insight into the impedance-based moisture content measurement and to improve methodologies to monitor the moisture content of gas-phase biofilters. A sensor consisting of a sensing unit (three parallel plates) and a circuit generating DC voltage outputs was used in this study to measure moisture content. The sensor readings changed with step-wise increase of moisture content as well as different particle size distribution and nitrogen (ammonia-nitrogen, nitrate-nitrogen) concentrations of biofilter media. The results show that both particle size distribution and nitrogen concentrations significantly affected impedance-based moisture sensing. A mathematical model was formulated, which was able to demonstrate the relationship between the sensor reading and moisture content of the biofilter media. A model was established to predict the moisture content of the biofilter media based on sensor reading, ammonia-nitrogen concentration and nitrate-nitrogen concentration.

Graduation Semester

2016-12

Type of Resource

text

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http://hdl.handle.net/2142/95299

Copyright and License Information

Copyright 2016 Zhonghua Zheng

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