demonstration of biogas production using low moisture content

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DEMONSTRATION OF BIOGAS PRODUCTION USING LOW MOISTURE CONTENT DEMONSTRATION OF BIOGAS PRODUCTION USING LOW MOISTURE CONTENT BEEF CATTLE MANURE EXECUTIVE SUMMARY Beef cattle feedlots in the Texas panhandle produce more than 6 million beef cattle annually. The manure is deposited in open-lots, and is removed every 6 to 12 months. Traditionally, this manure has gone directly to land application following removal from the pens. At these beef cattle feedyards, annual manure production is about 36 billion pounds of fresh manure, equating to about 1.3 billion pounds after drying on the pen surface for 6 to 12 months. This amount of manure represents a tremendous biogas energy potential should economically methods be developed to harvest that energy. This research and demonstration project was performed to evaluate biogas production at ambient temperatures using beef cattle manure scraped from open lot feedyards. Three laboratory experiments were conducted to determine potential biogas production rates. In the first two laboratory experiments, biogas was produced in collapsible low density polyethylene (LDPE) containers. The permeability of the containers resulted in low biogas production rates and abnormal gas concentrations. The experimental procedures were modified for the third experiment and the biogas was collected by water displacement in Nalgene containers kept at 21° C (70° F). Manure in the third experiment had an initial volatile solids (VS) content of 32.0% dry weight basis. Biogas production rates were 0.0046, 0.12, 0.14, 0.13, and 0.035 liters per gram VS at wet basis moisture contents of 50, 60, 70, 80, and 95%, respectively. Biogas production rates were steady throughout the 8 months that biogas was produced. A field demonstration project was conducted to determine feasibility of collecting biogas using "landfill-type" cells. Two 91m 3 (3,200 ft 3 ) cells were excavated in the native soil to a depth of 6 feet. The cells were lined on the top and bottom with EPDM geomembranes, and manure at a wet basis moisture content of 60% was placed within the cells. The first cell was loaded with manure (initial VS=32.0% dry weight basis) in February, 1999, and began biogas production around August 1, 1999. Biogas production ceased around October 23, 1999. During the 12 week period, the first cell produced a total of about 1,500 m 3 (53,000 ft 3 ) of biogas with a maximum methane concentration of 52%, for a biogas production rate of 0.10 liters per gram VS. The second cell was loaded with manure (initial VS=41.9% dry weight basis) in January, 2000, and has not produced any biogas to date. This research and demonstration project demonstrated that biogas could be produced in landfill cells using beef cattle manure scraped from open lots. The biogas production appears to be highly temperature dependent, as biogas was produced for only 7 weeks out of the year. Thus, biogas production with beef cattle manure may not be feasible unless the cells are heated so that biogas could be produced year-round. Further studies are warranted to continue development of an economical method for biogas production from beef cattle manure collected in open lots. Back http://www.westbioenergy.org/cattle/execsumm.html [3/26/2003 8:52:51 AM]
INTRODUCTION DEMONSTRATION OF BIOGAS PRODUCTION USING LOW MOISTURE CONTENT BEEF CATTLE MANURE INTRODUCTION About 6.3 million beef cattle are fed each year in feedyards in the Texas Panhandle area (Figure 1). In addition, more than 3.4 million hogs are grown in the same area. There are 70 feedyards in the area with capacities greater than 20,000 cattle, with several lots as large as 50,000 to 85,000 head. About 36 billion pounds or 16 million metric tons of manure (wet basis) are produced at beef cattle feedyards alone (Parker et al., 1997). The potential biogas energy production from this vast amount of manure would be immense if an economical method of production was found. Figure 1. Cattle Feeding Area Covering Twenty-Six Counties in Texas, Two Counties in New Mexico, Three Counties in Oklahoma, and Three Counties in Kansas Manure production and management at beef cattle feedlots differs from most dairies and swine operations. At beef cattle feedlots, manure that is deposited on the ground is scraped and removed every 120 to 365 days, as opposed to swine and dairy operations that scrape or remove manure as often as every day. As a result, beef cattle manure contains more foreign matter (soil, rocks) and less volatile solids than swine or dairy manure. These solids cause problems in conventional biogas digesters. A typical open-lot beef cattle feedyard is shown in Figure 2. Beef cattle manure has a much lower moisture content than dairy and swine waste because water is not added http://www.westbioenergy.org/cattle/intro.htm (1 of 2) [3/26/2003 8:52:52 AM]
Page 1 and 2: DEMONSTRATION OF BIOGAS PRODUCTION
Page 3: DEMONSTRATION OF BIOGAS PRODUCTION
Page 7 and 8: LITERATURE REVIEW DEMONSTRATION OF
Page 9 and 10: OBJECTIVES Dr. Brent Auvermann is a
Page 11 and 12: OBJECTIVES The field phase of the e
Page 13 and 14: OBJECTIVES Figure 7. Loading manure
Page 15 and 16: Results and Discussion diffusion th
Page 17 and 18: Results and Discussion Figure 8c. E
Page 19 and 20: Results and Discussion Figure 9a. E
Page 21 and 22: Results and Discussion Figure 9f. E
Page 23 and 24: Results and Discussion Figure 10d.
Page 25 and 26: Results and Discussion Figure 13. T
Page 27 and 28: Results and Discussion 95% Moisture
Page 29 and 30: Conclusions CONCLUSIONS AND SUGGEST
Page 31 and 32: 75% Moisture 50% Moisture 40% Moist
Page 33 and 34: Experiment 3 50%Moisture 60% Moistu

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