Auburn Test

Feedstock Efficiency Tests with a small Pickup-mounted Down Draft Gasifier

From the article:

Objective

The objective of this study was to determine composition and performance of synthesis gas from gasification of selected alternative feedstocks being tested for co-firing in the Lafarge Roberta Cement kiln at Calera, Alabama, using a small down draft gasifier mounted on a pickup.

Procedure

Different feedstock mixtures were tested in a small biomass gasifier mounted on a Dodge Dakota pickup (Figure 1). Wood was used as the primary feedstock, then tested with mixtures containing 80% wood and 20% of broiler litter, switchgrass and plastic (Figures 2, 3 and 4) on an as-is weight basis. Gasoline was used as a reference point. The following steps were taken for each feedstock combination:

1. Modifications were made to the pickup so that the gas tank could be drained completely dry, and to the gasifier so samples of the syngas could be easiliy drawn for analysis.

2. Prior to the gasifier tests, the pickup was driven on 2 gallons of gasoline to provide a point of reference. The gas tank was completely drained to be sure that the 2 gallons of gasoline were accurately measured (Figure 5)

3. Feedstocks were accurately weighed on a medical scale (Figure 6) and loaded into the gasifier (Figure 7), being sure the mixture was spread as evenly as possible from top to bottom.

4. Feedstocks were sub-sampled for composition analysis, including ultimate and proximate analyses, and ash fusion temperature, at the Alabama Power Analytical Lab, Calera, AL.

5. Performance of each feedstock combination was determined by driving the pickup on the NCAT test track (Figure 8) at 50-55 mph till the fuel was completely used up. Exact time and distance and weather conditions were recorded.

6. Approximately every thirty minutes after starting the performance test for each gasifier feedstock, the pickup was stopped to measure composition of the synthesis gas (% hydrogen, carbon monoxide, methane, carbon dioxide and oxygen; Figures 9, 10, 11 and 12) being produced, with a gas analyzer. This resulted in 4 readings per feedstock.

7. Efficiency for each feedstock was calculated by determining the distance traveled per unit of energy.