Performance of a Small-Scale, Variable Temperature Fixed Dome Digester in a Temperate Climate

Energies

Juan M. Castano¹  Jay F. Martin¹ 

[1] Department of Food, Agricultural and Biological Engineering, Ohio State University, 590 Woody Hayes Drive, Columbus, OH 43210-1057, USA; E-Mails:

关键词: anaerobic digestion;    dairy manure;    biogas;    organic loading rate;   

DOI  :  10.3390/en7095701

来源: mdpi

【 摘 要 】

Small-scale digesters, similar to popular Chinese designs, have the potential to address the energy needs of smaller dairy farmers in temperate U.S. climates. To assess this potential, a 1.14 m³ (300 gallon) modified fixed-dome digester was installed and operated, at variable temperatures (5.3 to 27.9 °C) typical of the Midwestern United States, from March 2010 to March 2011 (363 days). Temperature, gas production, and other variables were recorded. The system was fed with dilute dairy manure with 6% volatile solids (VS) and an organic loading rate (OLR) ranging from 0.83 to 2.43 kg volatile solids (VS)/m³/day. The system was loaded with no interruption and exhibited no signs of inhibition from July 2010 to mid-November 2010 (129 days). During this period the digester temperature was over 20 °C with an average daily biogas production of 842 ± 69 L/day, a methane yield of 0.168 m³/kg VS added, and a Volatile Solids reduction of 36%. After the temperature dropped below 20 °C, the digester showed signs of inhibition and soured. These findings suggest that an ambient temperature, modified fixed dome digester could operate without temperature inhibition for approximately six months (169 days) a year in a temperate climate when digester temperatures exceed 20 °C. However, during colder months the digester temperature must maintained above 20 °C for viable gas production year round.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.