Recycling Organic Solid Wastes By Using Pyrolysis Techniques Of Energy And Biochar Production: The Case Of Khat In Jimma Town.

Abstract

Biochar is a carbon-rich solid material produced during pyrolysis, which is the thermochemical conversion of biomass in the absence of oxygen. Biochar can be used for soil and compost amendment to increase agronomic productivity. It reduces greenhouse gases, such as carbon dioxide and methane, are released into the atmosphere imparting on global warming. When the objective of these thesis was to process recycling organic solid wastes by using pyrolysis techniques of energy and biochar production from khat waste (local name in leftover Geraba). The method was purely experimental in the laboratory as well as in the field where samples to tested by using laboratory equipment. Procedurally, organic waste (khat) was changed into the energy and biochar in pyrolysis techniques by selected stoves. When the biochar production used for soil fertility, which was described their effects by growing the same species like maize with biochar and without biochar. The temperature profile during pyrolysis was determined using a K type thermocouple. The production of biochar from normal nelia and continuous feeding type anelia stove at the same heating temperature and time through measuring biomass bed temperature of stove was undertaken. For the comparison the same two points was selected in the solid domain of the stove geometry from 10cm below from top and 10 cm above from the bottom, the data was measured by inserting K-type thermocouple by the help of Digital thermometer in ten minute difference up to 60 minutes. Bulk density, pH and surface area of the biochar was measured. The biochar produced is highly alkaline, with all pH values recorded in 60 minute the pH 8.2 for N.A stove and C.A stove in solar (open drying) test, and N.A stove and C.A stove in oven tes is 8.3 and 7.8 respectively. After the experimental test results, the continuous anelia feeding type stove is modeled based on experimental temperature results to validate its temperature profile distribution differences by CFD simulation. When the CFD simulation temperature profile distribution is greater than the experimental, and generally it shows that the experimental temperature more accurate than the simulation temperature.