Mass Balance. Taking the
raw paper sludge input as datum (100%), the mass distribution
of the lab-scale experiments are shown in Figure 8. It should benoted that the additional water used to mock up HTT was also
equal to the raw paper sludge input (one to one mass ratio). At
200 °C treatment condition, the product after the HTT was
increased from 60.1 (100%) to 96.5 g (151.4%). After
dewatering, the liquid part was 55.8 g (92.9%) while the solid
product was approximately 35.1 g (58.5%). Then, in the drying
test, 21.5 g (35.8%) of moisture was evaporated; the dried mass
of the product was 13.7 g (22.7%). From the lab-scale solid fuel
production process, the dried solid input was 24% (moisture
content 76%), and 22.7% dried solid fuel was recovered
accounting 94.6% of fuel recovery.