Environmental Engineering Reference
In-Depth Information
10.4
On-line PAT measurement and theory of sampling concept in a
full-scale biogas fermentor or bioreactor setting (Holm-Nielsen, 2008).
Representative mass reduction - so-called 'riffle splitting' or similar
(more detailed info can be found in Petersen (2005)).
.
Particle size reduction - grinding or crushing.
.
.
Lot dimensionality transformation (3D or 2D
1D or 0D) - transform
three-dimensional and two-dimensional sampling places into optimal
one-dimentional
sampling places
such as a pipeline (reactors or
fermentors are 3D).
To overcome the difficulties in TOS-correct reactor sampling, a recurrent
loop sampling concept can be introduced; this is essentially transforming the
three-dimensional bioreactor sampling issue into a one-dimensional pipeline
sampling situation (Fig. 10.4). To be fully representative, a vertical recurrent
loop concept should be implemented. From such an external loop, pumping
from the bottom of the reactor to the top, a full cross-section of the upward
flow could be achieved as a composite sample by taking as many increments
as necessary (Gy, 1998). Such a set-up would ensure an optimal ability to
represent the entire volume of the fermentor. Structural correctness means
that all parts of the sample material have an equal probability of being
selected in the sampling procedure. This can obviously never be the case
when samples are extracted from the side of a bioreactor (Petersen 2005;
Petersen and Esbensen 2005; Mortensen and Bro, 2006).
Bioslurries in AD (and other fermentation processes) are almost always
pumped in pipelines, fed in semi-continuously or continuously into the
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