Table 1.

Pretreatment conditions and yields.

Sample	1	2	3	4	5
Reactor	VR	SE	SE	HR	HR
Acid concentration*	48	7.25	7.25	4.5	2.5
pH	1.3	1.6 to 2.7†	1.6 to 2.2†	2.2	2.3
Reactor Temperature	190°C	170°C	150°C	150°C	150°C
Residence time	1 min	30 min	30 min	3 to 5 min‡	2 to 4 min‡
Combined Severity§	1.3	0.8 to 1.9	0.8 to 1.3	-0.2 to 0	-0.5 to -0.2
Xylan removed	88.9%	88.9%	86.7%	83.1%	19.6%
Monomeric xylan Yield	72.1%	69.6%	61.3%	53.4%	2.1%
Total xylan yield	81.4%	79.2%	83.4%	79.9%	19.1%
Furfural yield	9.7%	9.7%	3.3%	3.3%	0.5%
Cellulose content	59.1%	62.9%	59.1%	57.0%	42.2%

*Concentration in mg Acid/g dry biomass.

† Addition of steam throughout reaction dilutes the sample and changes the pH.

‡Residence time distribution (± 2 standard deviations).

§Calculated as reported by van Walsum [21]