reactor was heated up by both the preheated hot nitrogen carrying gas and the electrical furnace. Hot nitrogen gas flows into the reactorfromthetoptothebottom.Thetemperatureofthereactorzone was controlled by regulating the electric power via a temperature controller. Biochar was discharged from the reactor after the reactor was cooled down to the room temperature following each run. All the condensable gases were collected in a water-cooled condensate receiver, and the non-condensable gases are collected by a gas sampling bag or discharged to a ventilation system [16] (see Fig. 2). In the present work, 0.67mm (3.18 mm screen size) pine sawdust dried in the PRECISION oven at 105C for 24 h was used for producing biochar samples. For each run, around 20– 30g dry pine sawdust sample was loaded into the unit. For the preparation of biochar at different biochar yield and carbon content, five reaction conditions were selected: 280C for 52 min, 290C for 30 min, 300C for 30 min, 330C for 30 min, and 450C for 30 min. During the biochar production, the nitrogen flow rate was set at 0.014 Nm3/min. At the end of carbonization reaction, N2 flow rate was increased to 0.028Nm3/min to cool down the biochar sample. Four thermocouples are located in the unit to monitor the temperature, CH0 for the preheated N2, CH1 for the biochar sample, CH2 for the reactor wall temperature and CH3 for the furnace temperature. The following procedures were followed in setting and controlling the reactor temperature: (1) preheating the nitrogen flow and the furnace to a temperature of 210C, which takes about 25 min; (2) setting up the furnace temperature to 30–40C above the target biochar production temperature, which enables the sample to be heated to the target temperature over a few minutes; (3) controlling the furnace temperature to maintain the sample at the target temperature over a targeted residence time; (4) turning off the gas heater and furnace power to cool the unit by keeping the nitrogen flow at a higher rate, until the sample temperature dropped to below 200C; (5) continuing the cooling for a few hours without nitrogen flow, until the sample temperature dropped to room temperature before the biochar product was discharged. During the pre-heating period below 210C, it was checked that there was negligible decomposition of loaded samples in the reactor.