ABSTRACT
The effect of particle size on the gasification performance of a pilot-scale (25 kg/h) downdraft fixed bed gasification system was investigated using prunings from peach trees at five different size fractions (below 1, 1-2, 2-4, 4-6 and 6-8 cm). The gas and hydrocarbon compositions were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC-MS), respectively. With increasing particle size, gas yield increased while tar and dust content decreased. The lower heating value of the gas decreased slightly with particle size. At a smaller particle size, more hydrocarbons were detected in the producer gas. Hydrogen and carbon dioxide contents increased with the decrease in particle size, reaching 16.09% and 14.36% at particle size below 1cm, respectively. Prunings with a particle size of 1-2 cm were favorable for gasification in the downdraft gasifier used in this study.
Subject(s)
Bioreactors , Gases/chemical synthesis , Heating/instrumentation , Incineration/instrumentation , Prunus/chemistry , Equipment Design , Equipment Failure Analysis , Particle Size , Pilot ProjectsABSTRACT
To improve the enzymatic digestibility of sweet sorghum bagasse and bioethanol production, five pretreatment methods have been investigated and compared, including (1) dilute NaOH solution autoclaving pretreatment, (2) high concentration NaOH solution immersing pretreatment, (3) dilute NaOH solution autoclaving and H(2)O(2) immersing pretreatment, (4) alkaline peroxide pretreatment and (5) autoclaving pretreatment. Among them, the best result was obtained when sweet sorghum bagasse was dilute NaOH solution autoclaving and H(2)O(2) immersing pretreatment. The highest cellulose hydrolysis yield, total sugar yield and ethanol concentration were 74.29%, 90.94 g sugar/100g dry matter and 6.12 g/L, respectively, which were 5.88, 9.54 and 19.13 times higher than the control. Moreover, the FTIR and SEM analysis illustrated significant molecule and surface structure changes of the sweet sorghum bagasse after pretreatments.
