Transcript Analytical Instruments for Todays and Future Fuels

New H2S Analyser
IP 570 Determination of Hydrogen Sulfide in fuel oils
– Rapid liquid phase extraction method
for Bunker Fuels and Refinery Feedstock Components
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H2S a new issue, but of increasing global concern
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H2S present within refineries, terminals, oil storage systems, during
bunkering and bunker handling on board the ship, during carriage and
handling of crude oils.
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H2S can be released during oil/fuel transportation due to heat & agitation.
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Exposure to H2S has caused death and serious injuries, a significant
concern to Underwriters in the Marine industry.
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IMO, major oil companies, shipping companies issue guidelines on the
dangers of H2S.
....precise monitoring of H2S concentrations is a major safety concern
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Levels of H2S may be found in:
• Petroleum products
– petroleum products, especially residual fuel oils that often
contain some dissolved H2S entrapped after processing
– crude oils
• Sulfur reducing bacteria
– predominantly distillate fuels
– does not significantly increase the H2S levels
.... screening for H2S is very important
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H2S issues for the Marine/
bunker industry:
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Health and safety
– Colourless and volatile gas
– Generates flammable
headspace gases
– Highly toxic and potentially
lethal
– Acts upon central nervous
system – narcosis
– Exposure limits 10 ppm over
a period of 8 hours
– Fatalities do occur
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L
O
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0 to 10ppm
Irritation of the eyes,
nose and throat
10 to 50ppm
Headache and
dizziness
Nausea and vomiting
Coughing and
breathing difficulty
50 to
200ppm
Severe respiratory
tract irritation
Eye irritation/acute
Shock
Convulsions
Coma
Death in severe
cases
M
O
D
H
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G
H
H2S issues for the Marine/bunker industry:
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Corrosion
– Above the cargo – H2S contributes to mild steel corrosion
– On board tankers – potential to damage electronics, instruments and
sensors
– Cost!
Need for a robust instrument that offers fast and reliable H2S analysis
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H2S within the Marine/ Bunker industry:
• H2S concentration in vapour depends on:
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H2S content in the cargo (liquid phase)
Amount of air circulation
Temperature of air and cargo
Cargo level in the tank
The exact configuration of tank venting arrangements
Amount of agitation
Duration of storage
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• H2S within the Marine/ Bunker industry:
• H2S has a high partition coefficient between liquid
and vapour – 1 ppm in the liquid phase can give rise
to a 100 ppm concentration in a vapour space.
• No proven rules for the tendency of releasing H2S
into vapour phase.
....Accurate liquid phase testing of cargo is crucial and
the only way to establish true H2S concentrations
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Current tests for H2S
IP 399 Determination of hydrogen sulfide
in fuel oils
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Complex spectrophotometric procedure
Measures H2S in liquid phase
3 hour intensive preparation required
Chemical process needs lengthy
technician time
– Uses toxic chemicals
– Many opportunities to lose H2S vapours
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Current tests for H2S
ASTM D5705 - Draeger tubes
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Glass tubes filled with a chemical reagent
100ml sample of air is drawn through the tube
Colour change indicates concentration
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Easy to use
Poor precision
Only measures H2S in the vapour phase
Some known interferences
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New H2S Analyser developed to meet industry needs
Unique NEW instrument for measuring H2S in liquids
– Automatic & easy to use
– Suitable for Lab or portable testing
– precise result in 15 minutes
– Pre calibrated detector with a 2 year expected life
– Integrated computer, colour display and air pump
Basic principles
– Measures H2S ppm (mg/kg) in fuel oils
– Utilizes gas extraction combined with an H2S detector
– Air is bubbled through the heated sample
– Instantaneous readings are integrated and converted to ppm
(mg/kg)
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Key Components
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Purging
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Insert weighed 5 ml sample
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Start Test
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Calibration
• Static – H2S detector is factory calibrated to give a fixed mV
output per ppm v/v
• Dynamic - H2S detector is factory calibrated using two H2S
control standards with a known mass of H2S. This calibration
then enables results to be shown in ppm (mg/kg)
• Air flow is factory calibrated
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Verification
• Using nitrogen containing a certified amount of H2S.
• This can be carried out by the user or distributor
Service
• The calibration of the detector enables a detector to be quickly
changed in the lab or in the field by replacing the detector
• Local calibration may be carried out using certified gas
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SetaAnalytics
Results
Hydrogen Sulfide Analyser
Instr. S/N : 10001278000000
Sensor S/N : 02.09465093 027
S/W Ver_M : 1.0A
S/W Ver_S : 1.28
Date 02 Nov 2007
Start Time 17:10:07 hr:min:sec
Total Test No. 000105
Sample weight 4.512grams
Test temperature 60oC
Sample ID :
Operator ID ABCA
Test method IP 570
H2S value 1.90 mg/kg (ppm)
Test duration 15 min
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Repeatability and Reproducibility vs H2S Concentration
IP 570
Repeatability and Reproducibility (mg/kg)
3.00
2.50
Reproducibility
2.00
Repeatability
1.50
1.00
0.50
0.00
0
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4
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12
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H2S Concentration (m g/kg)
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Data courtesy of the Energy Institute
Samples used in the round robin
Sample No.
Description
Viscosity (mm2/s at 50°C)
1
RFO Vacuum distillation unit feed
677
2
RFO Vacuum distillation unit feed
620
3
RFO High sulfur visbreaker residue
4
RFO Blend stock
927
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RFO Vacuum distillation unit feed
1455
6
RFO Blend stock
438
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RFO with scavenger
2149
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RFO Cracked vacuum distillate
29.7
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RFO 380
389
10
RFO 380
363
11
RFO 500
471
12
Diluent oil
65.4
13
RFO 180
211
14
RFO 200
213
15
RFO vacuum residue with scavenger
1986
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3000
Data courtesy of the Energy Institute
Latest comparative data:
IP 399 vs IP 570
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3.5
y = 0.8346x
R2 = 0.9354
H2S Level by IP 399
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2.5
2
1.5
Result Data
Linear (Result Data)
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0.5
0
0
1
2
3
H2S Level by IP 570
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4
5
Summary:
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The Energy Institute (IP) has published a new test method IP 570
The new Analyser measures H2S in the liquid phase
Good relationship with results from IP 399. H2S analyser has better precision
and can measure to lower H2S levels than IP 399
Precision is excellent
Test times are 15 minutes
Results are simply a ppm (mg/kg) level.
Operator requirements have been considerably reduced
Reliable measurements from 0ppm to 250ppm
RS232 interface
30 test data storage
Sensor protection with bypass loop
Automatic check for leaks using mass flow controller
H2S limit has been recommended for inclusion within specifications
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Typical User Applications
Refineries
• to assist control & reduction of H2S during refining processes
• Checking of final blended bunker fuels at the refinery tank farm
• Checks of product in storage at the refinery & bunker terminal
At loading & onboard ship
• To access chemical remediation using H2S treatment additives
New IP 570: Oil and Marine industry moving to adopt this new
Analyser for Health and Safety product reasons
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