*2.2. Carbonization Pilot Plant Description*

The EOP carbonization was carried out in a pilot plant installed at ENIS, which is illustrated in Figure 1. It includes a metallic pyrolysis chamber connected to a combustor of recycled carbonization volatiles that are transported by two insulated gas channels. The combustor is connected to a heat exchanger, which heats the carbonization chamber through hot combustion gases. The carbonization temperature is controlled by a thermocouple. The carbonization chamber was filled with about 50 kg of the EOP and then underwent a first pre-heating step using a gasoline burner in order to carry out the drying phase of the EOP biomass. From a temperature of about 400 ◦C, the EOP biomass was decomposed, and the carbonization volatile gases, which were generated from the carbonization chamber and circulated through the insulated gas channel, replaced the gasoline and ensured the auto-feeding of the flame in the combustor. The EOP biochar was recuperated at the end of the carbonization experiment within the carbonization chamber. This carbonization experimental procedure took around 4 h. *C* **2023**, *9*, x FOR PEER REVIEW 7 of 27

**Figure 1.** Schematic diagram of the EOP biomass carbonization plant. **Figure 1.** Schematic diagram of the EOP biomass carbonization plant.

tion performance, and exhaust emissions. The percentages of C, H, N, and S (CHNS) of the biochar were determined using the Vario Micro Elementar CHNS system. The oxygen

The HHV of the biochar was calculated using Equation (11). The volatile matter, moisture, and ash content of the EOP biochar were determined using a thermogravimetric analysis and the ASTM D 482, respectively. XRF was carried out using the S4 Pioneer system in order to determine the chemical composition of the EOP biochar ash. X-ray diffraction (XRD) analysis was performed in order to identify the crystal structure of the EOP biochar, using a Philips X'pert Pro super Diffractometer with monochromatic Co Kα radiation in the 2θ range from 10° to 80° at a scanning rate of 2°·min−1. The layer dimension perpendicular to the basal plane, Lc, of the EOP biochar was obtained from the (002) reflection angle following the Debye–Scherrer equation, whereas the d-spacing was determined according to the Bragg formula, with n being equal to 1 and θ representing the

The porous morphology of a biochar is an important property to investigate, considering its relationship to the surface area, the distribution of the pore's diameter,its poros-

Representative SEM showing the primary particle sizes of the EOP biochar was recorded using a Hitachi S-4800 scanning electron microscope. In addition, an Autopore IV 9500 mercury porosimeter (Micrometrics, USA) was used to measure the pore volume distribution, the surface area, and the porosity of the EOP biochar by measuring the

The temperature-programmed oxidation analysis (TPO) of the EOP biochar sample was carried out using a thermobalance (NETZSCH STA, 449F3) with an air flow of about 80 mL·min−1 at the standard conditions of temperature and pressure (STP) and at a heating

The EOP biochar's chemical functional groups were identified by FTIR analysis using a Nicolet 380 spectrometer (Thermo-Scientific, Waltham, MA, USA) in the range of 4000– 400 cm−1. The standard IR spectra of hydrocarbons were used to identify the functional

rate of 10°C·min−1. The temperature ranged from room temperature to 1000 °C.

ity, and the effect of these parameters on gaseous species absorption.

amount of mercury penetrating into the sample pores [53].

*2.3. Physico-Chemical Characterization of the EOP Biochar* 

content was calculated by the difference.

(002) reflection angle [18].

groups of the biochar components.
