Page 6 - 4_TOC special applications

SCA-130-402

For this determination, proven methods are During this process, most of the generated
available. First, the dry matter (DM) of the carbon dioxide was also removed. The final
liquid manure is determined at 105 °C. The solution is subsequently transferred into the
dried liquid manure is subsequently annealed autosampler vials of the analyzer and
to a constant mass at 550 °C in a muffle automatically analyzed. For this purpose, a
furnace. The loss of mass during annealing small fraction is injected onto the 720 °C hot
corresponds to the organic content of the platinum catalyst. The organic substances
liquid manure. The ratio of methane gas are then converted into carbon dioxide and
concentration and organic content measured using an NDIR detector.
corresponds to the biogas production yield
(fermentation) and is a key criterion for the The advantage of this alternative method lies
fermentation of different types of biomass and in its suitability for automation. This way,
for the assessment of the efficiency of many samples can be processed
fermentation processes. automatically in sequence.
With the possibility of multiple injections, the
■ Innovative methods method also offers statistical reliability. In the
In order to avoid long annealing times for the muffle furnace, a combusted weighed sample
ODM determination, an alternative method for yields an ODM value. The suspensions are
the determination of the organic substance generally analyzed at least four times to
was sought. The TOC suspension method establish a mean value.
was considered suitable for this purpose. The
dried sample was weighed into an
Erlenmeyer flask and mixed with hydrochloric
acid to convert the inorganic carbon ■NPOC-Determination
compounds, such as carbonates and For the determination of the organic content
hydrocarbonates, to carbon dioxide. In the in liquid manure (duplicate determination from
next step, a dispersion device was used to two different approaches with each 5
break up and homogenize the suspension. separate injections) yielded the following
results:
Liquid manure NPOC RSD
(dried and [mass.- [%]
powdered) %]
Sample 1 44,1 0,8
Sample 1 44,2 1,9
Sample 2 44,2 1,6
Sample 2 42,5 1,4

1000
900
Signal[mV] 600

300
0
-100
0 5 10 15

Zeit[min]
Fig. NPOC-Peaks of suspension
Fig. Homogenisation of the suspension