Introduction to BMP - Analytics

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Donnerstag, 17. November 2016 2 Labor für Umweltingenieurwissenschaften

Donnerstag, 17. November 2016 3 Labor für Umweltingenieurwissenschaften

Hints – Reactor Handling

• Avoid leaving the incubator door open longer than necessary

• Take your bottles out and measure as quick as possible

• Release gas if necessary (in all reactors of one serie)

• Be careful with the valves

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Pressure measurement Experiment 1

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0.5

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Pre

ssu

re [

ba

r]

Time [days]

Blank Substrate

You get the final pressure values (per reactor & day) by:

• first sum up the pressures of each reactor

• and then subtracting the mean blank value of each day

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Pressure measurement Experiment 1

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600

800

1000

1200

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1600

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Pre

ssu

re [

mb

ar]

Time [hours]

B17 real B18 realReactor I Reactor II

How to calculate the BMP starting from here?

You get the final pressure values (per reactor & day) by:

• first sum up the pressures of each reactor

• and then subtracting the mean blank value of each day

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𝑉2 =𝑉1 ∗ 𝑝1 ∗ 𝑇2𝑝2 ∗ 𝑇1

𝑉1 ∗ 𝑝1𝑇1

= 𝑉2 ∗ 𝑝2𝑇2

V1 = [bottle volume (ml) – filling volume (300ml)]/1000 V2 = x (L) p1 = p Sum (mbar) Biogas p2 = 1013 (mbar) T1 = 311 K T2 = 273 K

Reactor BMP

Calculation – conversion into BMP

You end up with a volume. What do you need to do now?

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• Is the threshold value reached?

• Where is the threshold value?

• If it’s not yet reached is there a forecast?

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800

0 50 100 150 200 250 300 350 400

BM

P [

NL

ga

s /

kg

oT

S]

Time [hours]

Predicted B17 B18Reactor I Reactor II

Calculation – the predicted BMP

How to calculate the theoretical BMP?

Predicted

Calculation – the predicted BMP

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Use the Buswell equation

SOP – Anaerobic Digestion Analysis

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Mass balance parameters:

• TS

• oTS

• Gas quality

Process control parameters:

• pH

• Alkalinity

• Fatty Acids

Two main Parts:

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Mass balance parameter TS – total solids

• Duplicate sampling

• Absolute measure

• Aluminium dish

• 105°C

• Constant weight

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Mass balance parameter oTS – organic total solids

• Duplicate sampling

• Absolute measure

• Aluminium dish

• 550°C !!!

• Constant weight

Follow up analysis from TS

SOP – Anaerobic Digestion Analysis

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Mass balance parameters:

• TS

• oTS

• gas quality

Process control parameters:

• pH

• Alkalinity

• Fatty Acids

Two main Parts:

Homogeneous sampling

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Process control parameters

What do we measure and why?

pH alone is not enough

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Process control parameters Titration

• Titration with H2SO4 0.05 mole/L

• Fix Endpoints at pH: 5, 4.3, 4

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Process control parameters Titration preparation

• Sampling

• Centrifuging

• Filtrating

• Diluting

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Process control parameters Titration The Kapp equation:

𝑨𝒍𝒌 = 𝑨 ∗ 𝑵 ∗ 𝟏𝟎𝟎𝟎 𝑺𝑽

Alk = Alkalinity (mmol/L) A = Acid used to titrate from initial pH to pH 4.3 (ml) N = Normality (mmol/L) SV = Sample Size (ml)

𝑽𝑭𝑨 = 𝟏𝟑𝟏𝟑𝟒𝟎 ∗ 𝑵 ∗ 𝑩 𝑺𝑽 − 𝟑. 𝟎𝟖 ∗ 𝑨𝒍𝒌 − 𝟐𝟓

VFA = Volatile Fatty Acids (mg/L) B = Acid used to titrate from pH 5 to pH 4 (ml)

SOP – Anaerobic Digestion Analysis

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Mass balance parameters:

• TS

• oTS

• gas quality

Process control parameters:

• pH

• Alkalinity

• Fatty Acids

Two main Parts:

Homogeneous sampling Need of a control reactor

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Mass balance parameter Gas quality

Gas quality: ratio between CH4 : CO2

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Mass balance parameter Gas quality preparation

Follow the instructions at the lab to prepare the

samples for gas quality measurements

When do we measure what (in Experiment II)?

Analysis Interval

TS / oTS / of all components Start / End of the experiment

pH 2 times per week

Titration In critical moments (at the beginning)

Gas quality With every discharge of gas from the reactors

Schedule of today’s afternoon

• Quick introduction on the new material at the lab

• Pressure measurements

• Do the titration measurements (sampling reactor)

• Measure the gas quality (in assistance)

• End the TS measurement, that started last week

• Start the 0TS measurement

• Preparing the reactors for experiment II

• Start with the conversion from pressure to BMP