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Metrohm Petroleum Refinery Applications

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Metrohm Petroleum Refinery Applications Innovation to fuel profitability
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Page 1: Metrohm Petroleum Refinery Applications

Metrohm Petroleum Refinery Applications

Innovation to fuel profitability

Page 2: Metrohm Petroleum Refinery Applications

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

Page 3: Metrohm Petroleum Refinery Applications

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

Page 4: Metrohm Petroleum Refinery Applications

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

Page 5: Metrohm Petroleum Refinery Applications

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

Page 6: Metrohm Petroleum Refinery Applications

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.

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Page 7: Metrohm Petroleum Refinery Applications

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.

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Page 8: Metrohm Petroleum Refinery Applications

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.

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Page 9: Metrohm Petroleum Refinery Applications

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.

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Page 10: Metrohm Petroleum Refinery Applications

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

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Page 11: Metrohm Petroleum Refinery Applications

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.

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Page 12: Metrohm Petroleum Refinery Applications

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

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Page 13: Metrohm Petroleum Refinery Applications

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.

12

Page 14: Metrohm Petroleum Refinery Applications

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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Page 15: Metrohm Petroleum Refinery Applications

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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Page 16: Metrohm Petroleum Refinery Applications

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


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