Table 10.12.1 gives the products for a slow pyrolysis process at 1382 and 1652°F along with data for fast pyrolysis at 1450°F. The increase in gas yield and decrease in organic liquid with an increase in reactor temperature are evident. The hydrocarbon fraction of the gas decreases from 32.2 to 17.5% with an increase in temperature from 1382 to 1652°F, while the H2 and CO portion increases from 46.5 to 70.1%. This data shows that higher temperature pyrolysis gives significantly higher yields to lower Btu gas. The higher temperature apparently results in the destruction of hydrocarbons in the gas. Comparing values for solid waste is difficult because of the variability between feed stocks of MSW. Table 10.12.1 shows the data for a run at 1450°F where pyrolysis is rapid along with data for slow pyrolysis. These data indicate that the fast pyrolysis at 1450°F gives results which are closer to those of the slow, high-temperature pyrolysis process. The total CO and H2 is 72.6%, the total hydrocarbon 10.1%+ (undoubtedly higher but only CH4 is evaluated), and the gas volume 17,400 cu ft/tn. Unfortunately, the data for fast pyrolysis is not complete, and a full comparison on the yield is not possible.
Table 10.12.3 presents data for a process to convert MSW to fuel oil. The temperature for pyrolysis is low (932°F), and the reaction rate rapid. This low-temperature pyrolysis gives higher yields of organic liquids, and the gas has significant quantities of C2-C7 hydrocarbons not present at higher temperatures. Reducing the temperature for this same process by several hundred degrees results in an increase in the gas yield of 80%.
The data available substantiate the guiding principles previously outlined and explain the composition and quantities of the products and how they are affected by changes in composition, temperature, and heating rate. They do
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