Page 342 - Advances in Eco-Fuels for a Sustainable Environment

Thermal depolymerization of biogas digestate 297

6.5
Biocrude (wt%) 6.0 4.5
5.5
5.0
3.0
0 1.5 Initial press (MPa)
20
40 0.0
(A) Holding time (min) 60

6
Biocrude (wt%) 5 4.5

4
3.0
250 1.5 Initial press (MPa)
300 0.0
(B) Target temp. (°C) 350

6.5
Biocrude (wt%) 6.0 60

5.5
5.0 40
20 Holding time (min)
250
300 0
(C) Target temp. (°C) 350
Fig. 10.3 The combined effects of system variables on biocrude yield, (A) T¼300°C,
(B) t¼30min, and (C) p¼2.55MPa.

target temperature is also demonstrated in Fig. 10.4B. Our results are in agreement
with the results reported by Dote et al. [84]. They observed that the biocrude yield
increased with an increase in target temperature from 250°Cto300°Cand the
biocrude yield decreased when the temperature was further increased from
300°C to 340°C [84]. The effect of the reaction temperature on the biocrude yield
may be explained by recognizing that while a high temperature is necessary for
biocrude production, very high temperatures may cause the lower molecular
weight chemical compounds present in the biocrude mixture to be volatilized, lead-
ing to its gasification [85, 86].