Table 1.
Fuel characteristics of wood pellets fabricated with larch sawdust immersed in tap water (TW), sodium hydroxide (AK) and sulfuric acid (AC) solutions

Immersion condition		Moisture content (%)	Calorific value (MJ/kg)	Ash content (%)
Solution type	Time (hr)
Tap water (TW)	24				5.4 ± 0.6	19.1 ± 0.2	0.1 ± 0.1
	72	4.8 ± 0.1	19.4 ± 0.1	0.2 ± 0.0
	120	5.9 ± 0.3	19.5 ± 0.3	0.1 ± 0.0
1%-NaOH (AK-1%)	24	6.5 ± 0.7	18.9 ± 0.1	1.6 ± 0.1
	72	6.0 ± 0.4	18.8 ± 0.1	1.6 ± 0.0
	120	6.0 ± 0.1	18.6 ± 0.0	1.4 ± 0.2
2%-NaOH (AK-2%)	24	5.4 ± 0.7	18.9 ± 0.0	3.2 ± 0.1
	72	5.5 ± 0.7	18.8 ± 0.1	3.0 ± 0.1
	120	6.5 ± 0.7	18.3 ± 0.2	3.2 ± 0.2
1%-H2SO4 (AC-1%)	24	5.5 ± 0.5	19.4 ± 0.3	0.2 ± 0.1
	72	5.5 ± 0.7	18.8 ± 0.1	0.3 ± 0.0
	120	6.0 ± 0.5	18.7 ± 0.1	0.2 ± 0.1
2%-H2SO4 (AC-1%)	24	5.9 ± 0.1	18.4 ± 0.1	0.2 ± 0.1
	72	5.0 ± 0.4	18.1 ± 0.1	0.2 ± 0.0
	120	6.0 ± 0.4	17.6 ± 0.3	0.3 ± 0.1
Non-immersed larch sawdust		5.1 ± 0.2	19.0 ± 0.1	0.2 ± 0.1
NIFOS 1st-gradepelleta		≤ 10.0	≥ 18.0	≤ 0.7
ENplus A1b		≤ 10.0	16.5 ≤ Q ≤ 19	≤ 0.7

Each value is the mean ± standard deviation in triplicate.
Standard for the quality of wood pellets designated by the National Institute of Forest Science (NIFoS).
Specification of wood pellets for non-industrial use designated by the European Nation (EN 14961-2).