Pilot-scale conversion of lime-treated wheat straw into bioethanol: quality assessment of bioethanol and valorization of side streams by anaerobic digestion and combustion

Table 4 Fuel analysis results of the lime-treated wheat straw solid fraction (experimental and corrected for 85% calcium recycle) original wheat straw feedstock and untreated wood

Source composition		Lime-treated wheat straw solid fraction (experimental)	Lime-treated wheat straw solid fraction (corrected for 85% calcium recycle)	Wheat straw original feedstock (harvest 2003)	Wood (untreated, average)[28]
Parameter	Unit
Ash (550°C)	wt%_dry	27.2		12.6	---
Ash (815°C)	wt%_dry	27.0	19.5	11.5	1.5
Volatiles	wt%_dry	68.4	75.5	70.1	80.7
Moisture	wt%_wet	3.4^a	50^b	7.7	49.2
Higher heating value, measured	MJ/kg_dry	13.4	14.3	16.6	19.8
Lower heating value	MJ/kg_dry	12.4	13.2	15.6	18.5
Lower heating value (at 50% MC)	MJ/kg_wet	5.0	5.4	6.6	8.0
C	wt%_daf	43.1	44.9	46.5	51
H	wt%_daf	5.8	6.1	5.6	6.1
N	wt%_daf	1.5	1.5	1.7	0.3
O	wt%_daf	44.8	46.6	45.8	43
S	wt%_daf	4.56	0.71	0.15	0.06
Cl	wt%_daf	0.20	0.21	0.31	0.04
F	wt%_daf	0.0031	0.0031	---	0.0024
Al	mg/kg_dry	121	133	185	211
As	mg/kg_dry	5.4	5.9	< dl	less than dl
B	mg/kg_dry	5.2	5.7	4.1	9
Ba	mg/kg_dry	3.2	3.5	3.6	143
Ca	mg/kg_dry	52000	8600	4700	13000
Cd	mg/kg_dry	Less than dl	---	0.15	0.5
Co	mg/kg_dry	7.3	8.1	55	0.51
Cr	mg/kg_dry	10.2	11.2	0.2	5
Cu	mg/kg_dry	9.1	10.1	1.6	17
Fe	mg/kg_dry	160	170	220	120
K	mg/kg_dry	3000	3300	15000	2000
Li	mg/kg_dry	Less than dl	---	0.2	Less than dl
Mg	mg/kg_dry	870	36	1105	769
Mn	mg/kg_dry	33	36	14	214
Mo	mg/kg_dry	Less than dl	---	1.9	0.55
Na	mg/kg_dry	1500	1660	200	300
Ni	mg/kg_dry	5	5.8	0	8
P	mg/kg_dry	5100	5600	485	486
Pb	mg/kg_dry	Less than dl	---	1.1	32
Sb	mg/kg_dry	1.4	1.6	1.8	1.8
Se	mg/kg_dry	Less than dl	---	1.9	1
Si	mg/kg_dry	40000	44500	28000	900
Sn	mg/kg_dry	0	0	0.20	1.2
Sr	mg/kg_dry	23	25	18	14
V	mg/kg_dry	0.3	0.3	---	---
Zn	mg/kg_dry	25	27	0.6	0.4

ISSN: 2731-3654