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Metrohm Petroleum Refinery Applications
Innovation to fuel profitability
Impacting the Entire Refining ProcessRefineries are complex operations that convert crude
oil into a range of products. Optimizing the production
process to improve yield and maximize profitability is a key
objective of any refinery. A recent study found that losses
due to corrosion alone can approach $12 billion USD per
year. Metrohm offers innovative analytical methodologies
to improve process efficiency, protect against corrosion
and maximize profitability.
From crude oil to highly refined petroleum products,
Metrohm offers solutions that deliver value across the
refinery.
The table on the following page demonstrates the utility
of Metrohm products across the entire refining operation.
This brochure connects the regulatory needs of the
industry to our quality titration, ion chromatography, near-
infrared and process products.
Whether it is simply running a standard method or
implementing a customized process system, Metrohm is
ready to partner with you to help drive productivity and
profitability in your operation.
Driving Global StandardsStandard methods are more important than ever before
because these industry validated solutions streamline
testing, making it consistent in labs all over the world.
ASTM, UOP, ISO, IP and other global standards are
commonly used for product quality control testing as they
facilitate global commerce and are the basis of sound
economies.
The testing of crude and refined oil products is demanding
and requires precise and reliable analysis to meet regulatory
demands. Metrohm is actively involved with ASTM and
helps drive method development. We take on these
challenges and deliver solutions that improve accuracy and
efficiency.
Innovation to Fuel Profitability
1
PRODUCT PARAMETER TECHNOLOGY METHOD REFERENCE PAGE #
Crude Oil Total acid number Thermometric titration ASTM D8045 3
Total acid number Potentiometric titration ASTM D664 3
Water content KF volumetric titration ASTM D4377 3
Water content KF coulometric titration ASTM D4928 3
Salt content Potentiometric titration ASTM D6470 4
Organic halides Potentiometric titration ASTM D4929 4
Organic halides Combustion IC AN-CIC-14 4
Jet Fuel & Kerosene Acidity Potentiometric titration ASTM D3242 4
Hydrogen sulfide and mercaptans
Potentiometric titration ASTM D3227 4
Organic halides and sulfur Combustion IC AN-CIC-14 4
Water content KF volumetric titration ASTM D4377 4
Water content KF coulometric titration ASTM D4928 4
Liquefied Petroleum Gas (LPG) Hydrogen sulfide Potentiometric titration ASTM D2420 5
Water content KF coulometric titration AN-K-058 5
Organic halides and sulfur Combustion IC AN-CIC-018 5
Diesel & Biodiesel Blends Total acid number Potentiometric titration ASTM D664 6
Iodine number Potentiometric titration 8.000.6020 6
Water content KF coulometric titration 8.000.6077 6
Oxidation stability Oxidation stability EN15751(EN 14112) 6
Free and total glycerol content Ion chromatography ASTM D7591 6
Antioxidant content Ion chromatography TA-005 6
Sulfur content Combustion IC TA-049 6
Fuel Ethanol & Gasoline Blends pHe pH measurement ASTM D6432 7
Total acid number and acidity Potentiometric titration ASTM D7795 7
Water content KF volumetric titration ASTM E1064 7
Water content KF coulometric titration ASTM E203 7
Inorganic chloride content Ion chromatography ASTM D7319 & ASTM D7328 7
Total and potential inorganic sulfate content
Ion chromatography ASTM D7319 & ASTM D7328 7
PROCESS PARAMETER TECHNOLOGY METHOD REFERENCE PAGE #
Crude Desalting Total acid number of crude oil Online titration AN-PAN-1037 8
Salt in crude oil Online titration AN-PAN-1014 8
Desalted water anlaysis Online and lab titration AN-T-076 8
Mercaptans and hydrogen sulfide
Online titration AN-PAN-1026 8
Salt content (salinity) Conductometric method ASTM D3230 8
AlkylationOrganically bound halides in feed, process and alkylates
Combustion IC AN-CIC-018 9
Acid strength Online titration AN-PAN-1006 9
Residual moisture in alkyate gas KF gas analyzer AN-K-058 9
Sour Water Stripping Hydrogen sulfide and ammonia Online titration AN-PAN-1001 10
Anions, sulfide and ammonium in sour water
Ion chromatography AW IC-US-0218 10
Amine Treatment Heat stable salts Ion chromatography AN-S-343 10
Bicine Ion chromatography AW IC-US-0215 10
Amine strength Online titration AN-PAN-1003 10
Diesel & Gasoline Blending Monitoring
Cetane number, density, FAME, flash point, pour point, viscosity, cloud point
Online near-IR AN-NIR-022 11
Ethylene Cracking Various parameters Online near-IR AN-NIR-US-073 12
Water & Waste Water Analysis Various parameters Various technologies Various methods 13
Corrosion Monitoring Corrosion determination Electrochemistry Various methods 14
Crude OilCrude oil assays evaluate the physical and chemical
composition of crude oil feedstock. Each type of crude oil
has unique chemical characteristics that are important to
refiners, oil traders and producers globally.
Crude oil measurements can vary from a simple yield
determination to a complex evaluation of the quality of the
crude oil and all of its refined fractions. These evaluations
are critical to control corrosion in the refinery and greatly
impact the profitability of all refining operations given
the potential for significant loss in crude investments and
disruptions in the refining process that influence yield,
quality, production and environment.
Total Acid Number by ASTM D8045Acid Number (AN) is a critical quality control parameter for
crude oil and petroleum products. The accuracy of the AN
results has significant influence on the commercial value
of crude oil and the profitability of a refinery. Moreover,
acidic compounds lead to corrosion in petroleum refining
and transportation infrastructure, therefore accurate AN
measurements are necessary for safe operation. Given the
commercial and corrosion impact of acidic compounds
monitored by AN titrations, new method ASTM D8045
is critical to quality control laboratories throughout the
industry.
ASTM D8045 uses thermometric titration and improves
upon the traditional D664 analysis technique by utilizing
a sensor that is unaffected by difficult matrices, requires
lower solvent volumes, and completes sample analysis in
often less than two minutes.
Total Acid Number by ASTM D664Even though it is not as effective or reliable as ASTM D8045,
many laboratories still measure Acid Number using ASTM
D664. Metrohm has proven potentiomentric systems that
yield the most accurate results from D664 and provide a
high level of automation for worry free analysis.
Water Content by ASTM D4377 & D4928The determination of the amount of water in crude oil
and petroleum products has always been important.
Karl Fischer (KF) titration is the best water determination
method due to its excellent reproducibility and accuracy
as well as its ease of use. For these reasons, KF is called
out in numerous international standards. Water is not
homogeneously distributed in these products, which
means that the petroleum samples must be homogenized
before analysis. Furthermore, crude and heavy oils contain
tars that can contaminate electrodes and titration cells
leading to frequent reagent exchange and titration cell
3
cleaning. These additional steps add time and complexity
to these measurements. To ensure that the sample
completely dissolves, solubility promoters are added to the
methanol.
Metrohm offers both volumetric and coulometric KF
titrators for moisture determination in crude oil samples.
Chloride by ASTM D6470 & D3227Chlorides in crude oil form areas of salt accumulation in
processing units. These salt accumulations corrode key
equipment, especially those that run in low-temperature
ranges where hydrogen chloride forms. Refineries
constantly optimize the production process to improve the
yield of high value products. They lose their profit due to
the corrosion to the level of 1 billion per year. Protecting
plants against the corrosion caused by sulfur, chloride and
other organic acids is important in the context of safety
and profitability.
Chloride in crude oil is determined by potentiometric
and conductometric methods in accordance with ASTM
methods.
Organic Chlorides by ASTM D4929Organic chlorides in crude oil are known to cause severe
corrosion in crude tower overhead systems, therefore,
most refineries allow no more than 1 ppm (mg/L) organic
chlorides in the crude charge. There are two alternative
test methods for determination of organic chloride in
washed naphtha fraction; sodium biphenyl reduction
measured with potentiometry or combustion and
evaluation by microcoulometry. Metrohm Combustion Ion
Chromatography can be used instead of microcoulometry
for this measurement.
Organic Halides by Combustion ICCombustion IC enables the sulfur and halogen content in
combustible solids, liquids, and gases to be determined
by combining combustion digestion (pyrolysis) with
subsequent ion chromatography.
Combustion IC can detect of individual halides without the
interference that is encountered in any of the competing
detection methods for ASTM D4929
Jet Fuel & KeroseneTotal Acid Number by ASTM D3242The acid and base number may also be determined
by photometric titration with color indication of the
equivalence point. Metrohm offers a unique optical
electrode called the Optrode, a new sensor for photometric
titration. It is 100% solvent resistant thanks to its inert
glass shaft. Another key advantage of the Optrode is its
capacity for automation.
Water Content in Jet Fuel by ASTM D4377 & D4928Fuels contain mercaptans that are oxidized by iodine and
can falsely indicate a high water content.
The problem is addressed by adding N-ethylmaleimide,
which causes the SH groups of the mercaptan to add to
the double bond of N-ethylmaleimide. Normally the water
content in fuels is determined by coulometric titration.
With volumetric titration, a solubility promoter must be
added to the methanol.
Hydrogen Sulfide & Mercaptans by ASTM D3227Sulfur compounds in petroleum products not only have an
unpleasant odor, they are also environmentally damaging
and promote corrosion. For determining hydrogen sulfide
and mercaptans in gasoline, kerosene, naphtha, and
similar distillates, the sample is titrated with a silver nitrate
solution. In this titration silver sulfide (Ag2S) and silver
mercaptide are produced and two pronounced potential
jumps occur. The first endpoint corresponds to hydrogen
sulfide (H2S), the second to the mercaptans. The indicator
electrode for the titration is the Ag-Titrode with Ag2S
coating. Since both H2S and mercaptans are oxidized by
atmospheric oxygen and the arising oxidation products
cannot be determined titrimetrically, work must be carried
out under nitrogen atmosphere.
4
Organic Halides and Sulfur by Combustion ICThe burning of sulfur-containing fuel leads to the emission
of air-polluting sulfur oxides into the atmosphere.
Furthermore, high sulfur concentrations have an adverse
effect on the ease of ignition of fuels and their stability
during storage. Halogen concentrations in the refinery
process must also be analyzed due to the corrosion risk.
As a result, a fast and reliable method for determining the
halogen and sulfur contents is required.
The Combustion IC method is captivating, not only due to
its outstanding precision, but also because it has higher
sample throughput.
Jet Fuel Testing by Near-IR SpectroscopyMonitoring jet fuel properties is important because the
fuel used in aircrafts must meet rigorous specifications.
Near-infrared spectroscopy (NIR) is a fast method for fuel
analysis. Metrohm developed a unique calibration solution
for jet fuels testing in the laboratory.
The parameters that can be determined by NIR
include:
• API gravity
• Density at 15°C
• Aromatic content
• Cetane index
• Boiling profiles at 10%, 20%, 50% and 90% recovery
• Flash point
• Freeze point
• Hydrogen content
• Viscosity at -20 °C
Liquefied Petroleum Gas (LPG)Water Content in Liquefied GasesWater is a contaminant in fuels and its concentration
should be as low as possible. Water promotes corrosion
and leads to undesired reactions in the fuel. In the case of
liquefied petroleum gas, the challenge lies in the sample
measurement and the associated phase transition from
liquid to gas. In the sample cylinder, an equilibrium is
reached between the liquid and gas phase. Depending
on the sample, the water content in the gas phase can
be several times higher than that of the liquid phase.
Therefore, defined sampling is very important to ensure
accurate and reproducible results.
The 875 KF Gas Analyzer from Metrohm is a fully automated
solution to determine trace levels of water in liquefied and
permanent gases.
Organic Halides and Sulfur in LPG by ASTM D7990Fluorine, chlorine and sulfur contained in LPG can be
harmful to many catalytic chemical processes, lead to
corrosion and contribute to emissions pollutants. This test
method can be used to determine total fluorine, chlorine
and sulfur in processed and finished LPG products.
The Combustion Module (Oven + LPG/GSS) is comprised
of the combustion oven and the LPG/GSS module and
enables sample digestion during the pyrolysis of liquefied
gases and gases under pressure.
5
Sodium by Online AnalysisThe performance and life of combustion engines
optimized for LPG can severely deteriorate with elevated
sodium levels. Determining these levels at the downstream
stage helps refineries adjust process conditions. Metrohm
Process Analytics technologies use an ion-selective
electrode and the dynamic standard addition technique to
accurately measure sodium in LPG in the 0-2 ppm range.
Process measurements overcome traditional, lab-based ICP
or AAS, which cannot be implemented in the production
area.
Diesel & Biodiesel BlendsBiodiesel is sold both as pure fuel and in blends with fossil
fuels. The minimum requirements for biodiesel are set in
the specifications of EN 14214 (pure fuel and blend stock)
and ASTM D6751 (only blend stock). EN 14213 describes
the minimum requirements for biodiesel used as heating
oil. EN 590 applies to diesel fuels that contain up to 7%
biodiesel and ASTM D7467 applies to those that contain
between 6 and 20% biodiesel.
Acid Number by ASTM D664 & EN 14104The acid number is a sum parameter for all acidic
components; at the same time it is a measure for the
long-term stability and corrosiveness of the biofuel. The
smaller the value, the higher the quality. Standard EN
14104 stipulates a non-aqueous potentiometric acid-base
titration for determining the acid number.
Moisture DeterminationThe presence of water in biofuels reduces their calorific
value and increases the corrosion rate. Some biodiesel
fuels contain additives that can participate in side reactions
during the direct coulometric Karl Fischer titration. In this
case, Metrohm recommends that the biodiesel sample is
not injected directly into the reaction solution. Instead, the
water contained in the biodiesel should be driven off in
a Karl Fischer oven. The water is driven off at 120 °C and
transported to the titration cell of the KF Coulometer in a
stream of carrier gas (dry air or inert gas). This process can
be completely automated with the 874 USB Oven Sample
Processor.
Iodine Number by EN 14111Iodine number is a test for the number of double bonds in
a sample. It is the amount of iodine (in g/100 g sample) that
can be added to the sample under the given conditions.
The determination of the iodine number in fatty acids or
biodiesel is covered by European standard EN 14111.
Oxidation Stability by EN 15751 & EN 14112Fatty acid methyl esters are produced from a vegetable oil
and usually obtained from oil seed by transesterification
with methanol. Both feedstock and biodiesel have a
relatively short storage life as they are slowly oxidized by
atmospheric oxygen. The resulting oxidation products can
damage vehicle engines. For this reason, the oxidation
stability is an important quality criterion for biodiesel and
vegetable oils and must therefore be checked regularly
during manufacture and storage. The oxidation stability
of fatty acid methyl esters is included as an essential
parameter in EN 15751 & EN 14112 standards.
Free & Total Glycerol Content by ASTM D7591 & EN 14214The production of biodiesel from vegetable oils and
animal fats leads to the formation of free and bound
glycerol (monoglycerides and diglycerides) as by-products
after transesterification of the triglycerides. Incomplete
transesterification and/or separation of glycerol causes
glycerol contamination in the biodiesel, which speeds up
fuel aging and leads to deposits in the engine and blocked
filters. To ensure engines operate properly, ASTM D6751
and EN 14214 limit the maximum total glycerol content
(i.e., free and bound glycerol) to 0.24 and 0.25% (v/v),
respectively. Free and bound glycerol is determined by ion
chromatography with subsequent pulsed amperometric
detection.
Fuel Ethanol & Gasoline BlendsThe minimum requirements for fuel ethanol as a blend
component in gasoline are documented in standards EN
15376 and ASTM D4806. ASTM D5798 relates to ethanol-
gasoline blends E75-E85.
6
pHe Value of Fuel Ethanol by ASTM D6432 & EN 15490A combined pH glass electrode with ground-joint
diaphragm is recommended for measuring the pH value
in organic solvents. Because pHe determination according
to ASTM D6423 and EN 15490 is time-controlled, it is
essential that the sensor has a rapid response time. The
Metrohm EtOH-Trode with a special membrane glass and
the very precise fixed ground-joint diaphragm is particularly
suitable for measuring the pHe values of biofuels.
Conductivity of Fuel Ethanol Electrical conductivity is an important analytical sum
parameter for detecting and monitoring corrosive ionic
constituents in ethanol and ethanol fuel. Due to the
considerably lower conductivity in non-aqueous systems,
very sensitive measuring systems are required. The
stainless-steel conductivity measuring cell with Pt 1000
temperature sensor, in conjunction with the flexible 856
Conductivity Module, is ideally suited for this application
in accordance with DIN 51627-4.
Acidity by ASTM D7795Fuel ethanol is mixed with gasoline in various ratios to
reduce both the demand for gasoline and environmental
pollution. Denatured fuel ethanol may contain additives
such as corrosion inhibitors and detergents as well as
contaminants from manufacturing that can affect the
acidity of finished ethanol fuel. Very dilute aqueous
solutions of low molecular mass organic acids, such as
acetic acid, are highly corrosive to many metals, therefore,
it is important to keep such acids at a very low level.
Water Content by ASTM E1064 & ASTM E203The ASTM E1064 and EN 15489 standards describe
coulometric Karl Fischer titration for determining water
content. For water content >2%, the recommended
test method is volumetric titration as per ASTM E203.
The volumetric KF titrators from Metrohm meet all the
specifications required by the standards and are therefore
extremely suitable for this application.
Inorganic Chloride Content by ASTM D7179 & ASTM D7328Bioethanol is either used in pure form as a fuel or blended
with fossil fuels. Contaminants in the form of inorganic
chloride and sulfate salts are corrosive and lead to
deposits and blockages in the fuel filter and injection
nozzles. The international ethanol specifications EN 15376,
ASTM D4806, and ASTM D5798 regulate the sulfate and
chloride content in bioethanol and bioethanol fuel blends.
Total Potential Inorganic Sulfate Content in Fuel Ethanol & Gasoline Blend as per ASTM D7319 & ASTM D7328According to ASTM D7319, the total content of inorganic
chloride and sulfate is determined by direct injection of the
ethanol sample, separation on an anion exchange column
and measured using conductivity detection. If hydrogen
peroxide is previously added, sulfur-containing species
such as sulfites, sulfides, or thiosulfates can be oxidized to
form sulfate and are quantified as potential sulfate content.
7
Increase Your Profit Through Internal Process Improvement.Petroleum refineries are large and complex production
facilities. Once the crude oil price is fixed the profitability
can only be improved through process optimization. In
plant operation, plant integrity and safety, production
rate, product quality, and costs are primary considerations.
These all depend on comprehensive process control
through online and near-real-time monitoring of key
process variables, often in explosive, dusty, corrosive, and
hostile environments. Metrohm provides online analyzers
specifically tailored to your process needs. In addition
to dedicated analyzers, we specialize in suitable sample
preconditioning systems that allow you to implement a
reliable online solution.
Explosion proof analyzers are available in a stainless- steel
version for Zone I or Zone II according to the European
explosive atmosphere directives (ATEX).
Crude DesaltingSalt Content by ASTM D3230Excessive amounts of chloride salts in crude oil result
in higher corrosion rates in refining units and have a
detrimental effect on catalysts. Desalting techniques are
well established, but continuous monitoring of the salt
content is needed for process control and cost reduction.
Salt in crude oil is determined by titration using ASTM
D6470 or by conductometric measurement with ASTM
D3230.
Water Content by ASTM D4347 & ASTM D4928Crude oil that comes in contact with water carries some
residual water. If the level of water in crude oil exceeds 0.1
to 0.5%, the distillation column will over pressurize. This
creates unnecessary wear on the column and a potential
safety issue. Water content in crude oil is monitored using
ASTM D4347 and ASTM D4928
Mercaptans & Hydrogen SulfideRaw oil contains several percent by weight of sulfur
compounds. These compounds not only have an
unpleasant smell, they are also environmentally harmful
and corrosive which is why they must be largely removed
during refining.
The 2045TI Ex Proof Analyzer with a flexible sample
pretreatment system is found in a very wide variety of
refinery applications. It monitors mercaptan and H2S
content in accordance with ASTM D3227 and UOP163
and can also be used for the determination of ammonia,
halogen and phenol content as well as for the bromide
index, saponification and acid number. The analyzer fulfills
EU Directive 94/9/EC (ATEX95) and is certified for Zones
1 and 2.
Chloride Monitoring in Crude DesaltingMonitoring of the chloride in crude and after desalting is
needed to check the desalting process efficiency and to
overcome corrosion problems in downstream processes.
The analytical measuring method is ASTM D3230 by
conductivity detection. Since the sample take off point
is typically in a hazardous environment the ADI 2045 Ex
Proof Process Analyzer is designed and equipped to meet
directives 94/9EC (ATEX95).
Desalting Water AnalysisA large portion of the water used in the crude desalting
process is recycled. The source of wash water for the
desalters varies widely; in some cases stripped phonic sour
water is used as wash water. Metrohm provides dedicated
online solutions for important water analysis parameters
such as: Sulfide, Ammonia, Phenol, pH, Alkalinity,
Hardness, Conductivity.
8
AlkylationIsobutane and olefin are feeds into the alkylation unit
which combines the olefin with butane to increase
octane and lower the vapor pressure of the product for
blending. Alkylation is used in combination with fractional
distillation, catalytic cracking and isomerization to
increase the yield of automotive gasoline. Either sulfuric or
hydrofluoric acid is used as the catalyst for the alkylation
reaction. Both catalysts operate at low temperatures and
high isobutane-to-olefin ratios to reduce the side reactions
and catalyst consumption. Sulfuric acid is a liquid under
normal operation conditions, while hydrofluoric acid is
a gas. Produced alkylates are passed through caustic to
remove residual acids.
Online Acid Strength DeterminationAcid acts as a catalyst in a refinery alkylation reaction,
therefore, a minimal amount of acid is required to
enable the reaction to occur. As acid strength declines,
undesirable side reactions increase and can cascade in
a runaway manner that consumes all of the acid in the
unit. This can lead to undesirable polymer formation or
oily sample formation depending on the type of acid used.
In the hazardous environment, rugged online analyzers
monitor the concentration of acid used in the alklyation
process.
Alkali concentration can be measured using a similar online
analyzer.
Monitoring Alkylation by CICInsufficient acid strength in the HF Alkylation unit can lead
to flurobutane formation. In an acid runaway situation,
the amount of organic fluorides in the alkylate product
elevates as acid is consumed and exits with the alkylate.
Metrohm provides easy to use solutions for the residual
organically bound fluoride and sulfur in iso-butane and
olefin feeds by CIC with a gas box that can withstand
pressure up to 400 psi.
Residual Moisture ContentThe alkylate is blended to make gasoline with specific
Research Octane Number (RON) values and residual
water content in the alkylate can induce corrosion. For
finished product quality assurance the moisture content
determination in the alkylate product is important.
The 875 KF Gas Analyzer from Metrohm provides
predefined methods for water content determination in
liquefied and permanent gases.
Sour Water StrippingSour water is condensed waste water produced during
many downstream refining processes containing hydrogen
sulfide, ammonia and other contaminating compounds. It
is often acidic in nature and can cause corrosion problems
within the refinery’s pipework so it must be treated before
it can be reused or disposed to the waste water treatment
plant.
Sour water is treated in the Sour Water Stripper (SWS)
which uses a steam stripping process to remove sulfides
and ammonia as gases. At optimum pH the sour water
mixes with steam and the ammonia and hydrogen sulphide
gas vent to the top of the stripper column to the Sulfur
Recovery Unit (SRU). The stripped water is either used to
produce steam in the reboiler or pumped within control
limits to the waste water treatment plant for further
processing
9
Online Monitoring of Hydrogen Sulfide and AmmoniaOnline analysis of ammonia and sulfides increases the
efficiency of the SWS which leads to significant steam
reduction and increased energy savings. Effectively
stripping and monitoring H2S and NH
3 is an essential
operation in the overall pollution reduction program of
refineries. The Process Analyzer 2045TI can analyze H2S
and NH3 simultaneously with automatic cleaning and
calibration using absolute wet chemical techniques. Fast
and accurate results are continuously transmitted for
process control.
Other contaminants that increase the sour water
corrosiveness like phenol and cyanide can also be analyzed
with Metrohm Process Analyzers.
Determination of Anions, Sulfide, and Ammonium by Ion ChromatographyDetermination of sulfide and other sulfur species is
critical for strict SWS process monitoring. While titration
is a suitable technique for the sulfide content, the
other corrosive sulfur species can be determined by ion
chromatography. The degradation products of sulfide,
such as sulfite, sulfate, thiosulfate and thiocyanate can
be monitored by suppressed ion chromatography. Sulfide
content in sour water can be monitored with UV detection
while ammonia content can be monitored by cation
exchange chromatography. Sample preparation steps such
as ultrafiltration and dilution can be automated.
Amine TreatmentAn amine treating unit captures hydrogen sulfide and
other acidic gases from the refinery gas streams and
concentrates them into an amine solution. It is also used
to capture acidic gases from raw or sour natural gasses.
Amine gas sweetening is a proven technology that removes
H2S and CO
2 from natural gas and liquid hydrocarbon
streams through absorption and chemical reaction. The
entire process is very energy intensive and results in high
operating costs. Optimizing the amine activity and usage
by online analysis is a critical step in reducing overall costs
and measuring the efficiency of the CO2 capture at the
same time.
Online Monitoring of Amine StrengthDetermination of free amine is an important parameter
to ensure acid gas removal. The alkalinity of gas washing
solutions containing alkanolamines is measured by
potentiometric titration with sulphuric acid using a
combined glass electrode.
A single online analyzer can monitor several sample streams
and determine the binding capacity of several amine
scrubbers in succession. By implementing Metrohm’s fully
automated online monitoring solution for this process, it
is possible to optimize the amine activity and measure the
efficiency of the acidic gas capture, reducing overall costs
while ensuring environmental compliance.
Monitoring Heat Stable Salt Formation by Ion ChromatographyHeat stable salts are a product of the neutralization reaction
between the alkaline amine and an organic or inorganic
acid (the neutralizing agent). Amine solutions extract other
contaminants that form salts of organic acids and sulfur
species such as oxalic acid, formic acid, thiosulfate and
thiocyanate. The accumulation of heat-stable salts not only
causes a reduction in CO2 absorption capacity, but also
causes a significant increase in the system corrosiveness.
Metrohm provides a simple to use Isocractic IC method to
determine heat stable salts.
Bicine Determination by Ion ChromatographyDuring degradation of these amines they form various
products, especially bicine which is corrosive. It is
extremely important to determine the accurate amount of
bicine in order to control corrosion and cost. Bicine can be
determined using cation exchange chromatography with
electrochemical detection.
10
Diesel & Gasoline Blending Monitoring
During the blending process, different fractions of the
crude oil distillation are mixed together to produce
ready-to-sell diesel or gasoline. This process is the most
economical when it is carried out in automated process
systems that work online. The endpoint of the blending
process is reached when the required fuel specifications
are achieved. Key characteristics, which indicate the
progress of the blending process, are the cetane number
for diesel blends and the octane rating for gasoline blends.
Near-infrared spectroscopy (NIR) sensors located directly in
the process enable the entire process to be controlled and
ensure a high-quality end product.
Parameters that can be monitored in parallel and inline are
listed in the table above.
Advantages of NIR Analysis in PetrochemistryNear-infrared spectroscopy has been successfully used in
oil refineries for years. NIR detects numerous parameters
in a single measurement in less than a minute. The cost
savings are enormous. Further advantages are:
• short response times and fast quality control
• improved product quality and process optimization
• reduced investment, analysis, and maintenance costs
• accurate and precise measuring results.
Real Time Blending Process Monitoring by NIRMonitoring the blending of a range of fuels is a direct
example of the success of NIR in the refinery. NIR detects
numerous parameters in a single measurement in less than
a minute.
Metrohm manufactures dedicated lab and process NIR
analyzers for diesel and gasoline analysis and blend
monitoring. These dedicated analyzers are provided
with start-up calibration that eliminates time-consuming
calibration development.
Gasoline Blends
• API• Alcohols & ether (MTBE, etc.)• Alkene content • Aromatic content
• Benzene content• Density• Motor octane number (MON)• Octane index number
• Research octane number (RON)
• Reid vapor pressure
Diesel Blends
• Boiling Point • Cetane number • Cloud point • Color
• Cold filter plugging point (CFPP)• Density• FAME content
• Flash point• Pour point• Specific weight• Viscosity
11
Ethylene CrackingApproaching 150 million tons per year, ethylene is the
largest volume industrially produced organic material.
Feedstock, typically naphtha or light gases (e.g., ethane,
propane), is first heated to high temperatures to break
down the feed into small hydrocarbon molecules. After
being cooled, the products are then sent through a variety
of separation processes with high purity ethylene being
one product stream among many.
Process optimization focuses on maximizing the output
of ethylene and other profitable products. Typically, a
Process GC is utilized for monitoring the cracking process.
However, these measurements are time-consuming and
maintenance-heavy. Near-IR with multicomponent analysis
capability can be used for real-time cracking process
monitoring.
NIR process analysis is a key component of process
optimization, because it provides process control with real-
time gas concentrations at various points in the process.
The use of fiber optics enables real-time sequential
measurements of up to 9 positions (e.g., feed, recycle
streams, product streams) with a single instrument. This
allows for rapid adjustments of the process to account
for changes such as differences in feed or temperature.
The net results of incorporating NIR into the process are
increased capacity, improved process reproducibility and
product quality. Further, the amount of process testing can
be shortened while enhancing plant safety. In combination
with a high pressure cell, NIR spectroscopy can also be
used as a tool for online, real-time analysis of industrial
gases.
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Water & Waste Water MonitoringMany of the processes in a petroleum refinery use water in large quantities. Refineries also generate a significant amount
of waste water that has been in contact with hydrocarbons. In addition, most organic and inorganic compounds found
in the refinery accumulate in this process water. To sustain this resource, refineries treat the waste water and reuse it for
various process applications. This requires treatment utilizing reliable analyses that monitor the composition of the water
continuously.
Raw water or source water for refineries could come from lakes, rivers, ground water or sea water. Due to the specific
requirements of process water in the refinery, all source water needs to be treated before being used for refinery applications.
Waste water from refineries contains high levels of
pollutants and is characterized by the presence of large
quantities of oil products and other chemicals that are
hard to degrade. With increasing regulatory limits and
stringent monitoring requirements, most refineries are
forced to use advanced water treatment, recovery and
process monitoring technologies. Major waste water
streams in refineries include desalter water, sour water,
spent caustic formed in the extraction of acidic compounds
from products, tank bottoms, and condensate blow down.
Below is a table listing analytical parameters monitored in
various water sources within the refinery.
Water Source Parameters of Interest Technology
Source water: Ground water, River water, Sea water, Rain water
pH, Conductivity, Hardness, Alkalinity, Chloride, Sulfate, COD,
ISE Measurement; Titration & Online Analyzer
Chloride, Sulfate, Nitrite, Nitrate, Phosphate & other anions
Ion Chromatography; Online IC
Sodium, Potassium, Calcium, Magnesium, Ammonium, Barium
Ion Chromatography; Online IC
Process Water: Hydrocracking steam condensatepH, Conductivity, Hardness, Alkalinity, Chloride, Sulfate, COD
Titration
Ammonia, Nitrite, Phosphate, Silica, Iron, Cobalt, Sulfide, Fluoride, Hypochlorite
Dedicated Online Analyzers
Desalter waste waterpH, Conductivity, Chloride, Sulfide, hardness, alkalinity
ISE Measurement; Titration; Dedicated Online analyzer
Sulfide, Ammonia, Phenol Dedicated Online Analyzers
Sour water Ammonia, Sulfide, Chloride Dedicated Online analyzers; Ion Chromatography
Cooling water & cooling tower blow down Calcium, Magnesium, Zinc, Phosphate, Silica Dedicated Online analyzers; Ion Chromatography
Spent caustic Cyanide, Phenol, Sulfide, Ammonia,Dedicated Online analyzers; Titration; ISE Measurement
Waste water treatment
Ammonia, Sulfide, Cyanide, Phenol, Nitrite, Nitrate, Total Nitrogen, Sulfate, Calcium, Magnesium, Barium, COD, Phenol, Total phosphate
Dedicated Online Analyzers
pH, Conductivity, Alkalinity, Hardness, Chloride, Sulfate
Measurement & Titration
Fluoride, Chloride, Sulfate, Nitrite, Nitrate, Phosphate, organic acids, hexavalent chromium, Sodium, Ammonium, Potassium, Calcium, Magnesium and other amines, Cobalt, Zinc
Ion Chromatography
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Electrochemistry Techniques Parameters of Interest ASTM Reference Methods
DC TechniquesLinear sweep voltammetryTafel slope analysisPotentio-dynamic polarization (LPR)
Polarization resistance (Rp)Corrosion rate (mm/Year)Corrosion currentCorrosion potential
ASTM G102 ASTM G59
AC TechniquesElectrochemical impedance analysis (EIS)
Film resistance & conductivityCharge-transfer resistanceSolution resistancePolarization resistance
ASTM G59ASTM G106
Chrono & other TechniquesElectrochemical noise (ECN)Critical pitting technique (CPT)Hydrogen permeation study Cyclic potentiodynamic polarizationHydrodynamic linear sweep
Redox kineticsPit initiationCrevice progressionHydrogen resistanceSurface morphology
ASTM G150ASTM G148ASTM G100ASTM G61ASTM F746ASTM F2129
Corrosion MonitoringReliable Corrosion Measurements via Electrochemistry
Refineries are complex systems of multiple operations that depend on the type of crude refined and the desired products.
They constantly optimize the production process to improve the high value products yield that maximizes profitability.
Refineries lose their profit due to the corrosion to the level of $1 billion per year. Protecting refinery plants against
corrosion due to the sulfur, chloride and other organic acids is important in regard to safety and profitability.
Metrohm offers innovative and improved analytical methodologies to improve process efficiency and to protect against
corrosion to maximize profitability.
Over the past three decades, several methods have been introduced to measure and monitor corrosion. While many of
these traditional methods such as weight loss or spray test analysis are quick and cost-effective, they can only offer a
qualitative overview of the process. In comparison, electrochemistry techniques are accurate, reproducible and often the
only method to measure corrosion rates on a quantitative basis. Electrochemistry has not only made it easy and direct to
measure the parameters governing the corrosion processes but has also helped greatly in the overall development of the
novel corrosion resistant films and corrosion inhibitors.
Depending on the nature of the application, different
electrochemical techniques are needed to determine
specific parameters of interest. Metrohm instruments
and pre-programmed methods provide ready-to-use
tools to determine these parameters. Metrohm offers
fully customized corrosion analyzers to evaluate corrosion
parameters for specific ASTM methods. A corrosion
software package with pre-programmed protocols is
provided with every analyzer at no charge. Corrosion
parameters of interest and the relevant ASTM methods are
summarized in the table below.
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9702.C1.1056 © 2016 Metrohm USA / Belgium. Metrohm and design® is a registered trademark of Metrohm Ltd.
Partner with Metrohm for ProfitabilityPetroleum refining is demanding and requires precise and
reliable analysis. As a leading manufacturer of instruments
for chemical analysis we are aware of these challenges.
We work closely with the petroleum refineries and with
the regulatory agencies such as ASTM and EPA to come up
with new and improved analytical methods that improve
overall product quality and profitability. Your partners at
Metrohm are experienced professionals who help you with
customized application support and service.
Quality ServiceMetrohm Quality Service begins before you purchase your
instrument and continues throughout its entire lifecycle.
Instrument experts help you make the right decisions to
satisfy your analytical and environmental requirements.
Application chemists assist you in every technical aspect,
from support in method development to troubleshooting
and process optimization. Our certified service engineers
are always on alert to provide emergency service in the
shortest possible time – wherever you are. Metrohm
provides the same high standard of service all over the
world by trained and certified service engineers based at
local Metrohm offices. After all, who is better qualified to
care for your instruments than the people who built them?
For more information visit: www.metrohm.be