Biochar From Municipal Solid Waste (MSW)

This research presents a model for the production of biochar from municipal solid waste using the slow pyrolysis technique. In this research, biochar production methods and the benefit of using them were investigated. The proposed location for establishing the studied plant is in the Nablus waste transfer station. The waste quantityand contents are the main parameters for the initial design. After preparing the process flow diagram, mass and energy balance equations were applied to calculate the products and energy needed. At the end, feasibility and environmental analysis were performed on the suggested plant. The city of Nablus and some neighboring villages export about 250 tons of waste per day, for pyrolysis process, only organicportion (53%)will be considered as the raw material. The amount of solid waste that is entered in a whole day (24 hours) is equal to (120201 kg/day), but this amount is divided into 6 cycles per day, and the duration of one cycle is 4 hours. Any quantity (20033 kg/4 hours) with a moisture content of 40% is entered. Right down to the drying process, the weight was reduced to (12924 kg / 4 hours) with a moisture content of 7%. The second part of the process, the drying process. To facilitate this process, the dryer is supplied with dry and hot steam. The process continues until the humidity reaches 7% where the reactor moisture should be less than 10% and the raw materials are fed into the shredder which reduces the volume of waste. Small dry pieces arrive at the pyrolysis reactor which starts the heating process from 500°C and the materials settle in the reactor for a period of time until biochar, bio-oil and syngas are produced which enter into the process repeatedly as heat energy for the reactor to continue working.The results indicate that for every 1 kg of material 0.35 biochar, 0.35 syngas, and 0.30 biooil at an energy input of 1.8 MJ/kg. Therefore, the energy required for this quantity (12,924 kg / 4 h) is estimated at 36060 MJ / 4 h. Also, the amount of heat required for the drying process is 26,289 MJ / 4 h. Three scenarios were also developed to determine the economic effectiveness of the project. Considering the initial cost of 16 million, the selling price of biochar and bio-oil was estimated as 0.65 ($/kg), 0.79 ($/kg), respectively. In another scenario, the selling price was 0.65 ($/kg), 0.22 ($/kg), respectively. Ending with the scenario that means selling bio-oil only at 0.79 (\$/kg). The expected payback period was 1.5, 2.5, and 7.5, respectively.