Characterization of Biochar Properties Affected by Different Pyrolysis Temperatures Using Visible-Near-Infrared Spectroscopy

Table 1

Average value and standard deviation of ash, volatile matter (VM), fixed carbon (Fc) contents, and calorific value (CV) of three types of raw biomass and charred materials under different pyrolysis temperatures.

Feedstock	Material	Raw	Pyrolysis temperature
type	property	biomass (control)	300°C	350°C	400°C	450°C	500°C	550°C	600°C
Cedar wood	Ash (wt.%)	0.3±0.1	1.5±0.3	1.6±0.1	1.6±0.1	1.8±0.1	1.8±0.1	2.0±0.3	2.1±0.1
	VM (wt.%)	82.4±0.1	37.5±0.7	34.8±0.3	32.6±0.7	29.3±0.5	25.8±0.6	21.5±0.5	18.4±0.4
	Fc (wt.%)	17.3±0.1	61.1±0.9	63.7±0.3	65.8±0.7	69.0±0.4	72.4±0.6	76.5±0.4	79.5±0.4
	CV (MJ/kg)	20.5±0.1	25.1±0.1	25.8±0.1	25.5±0.1	27.1±0.1	27.9±0.1	28.9±0.1	29.5±0.1
Pine wood	Ash (wt.%)	0.2±0.1	2.5±0.1	1.7±0.1	2.0±0.1	2.6±0.1	3.1±0.1	4.1±0.1	4.7±0.3
	VM (wt.%)	84.4±0.2	37.3±0.4	32.5±0.4	30.5±0.3	27.0±0.5	23.1±0.2	19.9±0.2	17.2±0.7
	Fc (wt.%)	15.4±0.2	60.2±0.5	65.8±0.5	67.5±0.3	70.4±0.6	73.8±0.2	76.0±0.2	78.1±0.9
	CV (MJ/kg)	19.2±0.1	25.6±0.1	25.9±0.1	26.5±0.1	27.6±0.1	28.6±0.1	28.7±0.1	28.8±0.1
Cotton stalk	Ash (wt.%)	5.4±0.1	6.0±0.1	7.6±0.1	8.3±0.2	9.5±0.2	9.2±0.2	11.1±0.1	10.1±0.1
	VM (wt.%)	74.4±0.1	32.2±0.3	29.9±0.3	24.6±0.3	23.7±0.3	20.8±0.6	18.2±0.7	15.6±1.2
	Fc (wt.%)	20.2±0.1	61.8±0.4	62.5±0.4	67.1±0.1	66.9±0.1	70.0±0.4	70.7±0.6	74.2±1.4
	CV (MJ/kg)	18.8±0.1	25.7±0.1	25.2±0.1	26.9±0.1	25.3±0.1	26.4±0.1	26.9±0.1	27.6±0.1