Purification solutions for the Gas Processing industry

Information contained in this publication or as otherwise supplied to Users is believed to be accurate and correct at time of going to press, and is given in good faith, but it is for the User to satisfy itself of the suitability of the Product for its own particular purpose. Johnson Matthey plc (JM) gives no warranty as the fitness of the Product for any particular purpose and any implied warranty or condition (statutory or otherwise) is excluded except to the extent that exclusion is prevented by law. JM accepts no liability for loss or damage (other than that arising from death or personal injury caused by JM’s negligence or by a defective Product, if proved), resulting from reliance on this information. Freedom under Patent, Copyright and Designs cannot be assumed.

© 2013 Johnson Matthey Group

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3

Proven processes for hydrocarbon purification

Low capital cost: fixed bed processes are simple and require only low capital outlay. It is possible to phase installation to match expenditure to the development of a project.

Impurity removal to very low levels: these can be as low as ppbv for H2S from natural and associated gas, copper strip 1A quality for propane/LPG and below 10 ng/Nm3(LNG quality) for mercury from natural gas. If required, total removal can be achieved.

Effective low temperature operation: PURASPECJM processes operate at temperatures from 0-200°C (30–400°F).

Easy retrofitting: to existing onshore and offshore installations.

PURASPECJM™ processes are based on fixed beds of catalysts and chemical absorbents which remove traces of contaminants from hydrocarbon gases and liquids. In particular the processes are designed to remove mercury and a range of sulphur compounds - most frequently hydrogen sulphide (H

2S)

and carbonyl sulphide (COS). They are widely used for ‘sweetening’ to meet pipeline specifications and ‘polishing’ to meet individual customer feedstock requirements.

No feedstock losses: only the impurities are reacted and absorbed.

High operating flexibility: PURASPECJM processes are flexible and accommodate changes in throughput. Operators are not required to run the plant, and change-out can be done by contract labour. The technology is truly ‘fit-and-forget’.

Environmentally friendly: there are no vents, flares, noise or problematic effluents and the plant has a minimal footprint. Used catalysts and absorbents can be reprocessed and disposed of in an environmentally sound manner. Energy use and CO

2 emissions during operation effectively zero.

The processes deliver a wide range of operating benefits:

You can depend upon PURASPECJM performance—it has already been proven in over 150 installations world-wide, including offshore and onshore applications.

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Case studies:

Customer driven product and application development

The PURASPECJM technology originated in 1984

in response to an Amoco requirement to remove

sulphur from the associated gas on the NW Hutton oil

platform in the North Sea. Since then both application

and product developments have been in response

to customer demand, and very often have been

accomplished in partnership with the customer.

Initial testing takes place at the Johnson Matthey

world-renowned catalyst Research and Technology

Centre at Billingham, UK. Frequently a customer will

supply a hydrocarbon sample together with a specification

to be achieved, and having identified a potential solution,

we go on to prove its viability using a laboratory reactor.

The next step may be a trial at the customer’s own plant.

For example, the first application of the process for

purification of a dense-phase natural gas stream

was carried out as a joint venture with BP Amoco. It

involved trials using a test vessel in a side-stream at

the world-scale processing plant on Teesside, UK.

The possibilities for development continue to unfold

and no potential application is too small. When the

British Museum asked Johnson Matthey if we could

prevent silverware in display cases from tarnishing we

obliged. We know of one brass band who protects

its instruments with a PURASPECJM absorbent.

Cost-effectiveness

The overriding driver for product improvement

in response to the needs of gas processing

customers is to minimize both capital

and operating costs. One PURASPECJM

absorbent is now into its fourth generation

of development and the absorption

capacity has increased by a factor of six

without a corresponding increase in costs.

At the same time the latitude of effective

operation, in terms of temperature and

pressure, has progressively broadened.

From our simple start in the North Sea we

have extended the application of PURASPECJM

technology into a number of major application sectors,

as exemplified by the case histories which follow.

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Case studies 1 & 2:

Achieving pipeline specifications for natural gas

Case study 1: Malaysia

As part of Malaysia’s Peninsular Gas Utilization

scheme, Petronas Gas Berhad is rapidly increasing

offshore production and onshore processing

of natural gas from the South China Sea.

Three of the four gas processing plants

constructed between 1992 and 1994

at Kertih, Terengganu, include

PURASPECJM process systems

and to meet growing demand,

they normally run at more

than design throughput

for sales gas and higher

hydrocarbon products.

The latest, larger plants

commissioned nearby, at Tok

Arun, process gas from newly

developed fields and each

contains a PURASPECJM unit to

ensure the sales gas specification will

always be met with respect to sulphur.

Case study 2: UK

The Morecambe Bay natural gas field off England’s

north-west coast meets more than 10% of the

country’s peak time demand. As a result of rising

levels of H2S from newly drilled wells, urgent

action was needed to meet the sales specification

without restricting production from the field.

After evaluating the alternatives, British Gas decided

to install a PURASPECJM unit at the onshore terminal

at Barrow-in-Furness. The system consists of two

identical vessels in series with piping to allow either to

be in the upstream lead position and with bypass lines

enabling absorbent to be replenished in one vessel

whilst processing continues in the other. The treatment

unit has now been in operation for over fifteen years

and successfully removes all H2S from the gas being

processed. This is mixed with bypassed gas, to achieve

the sales specification while minimizing absorbent

consumption. The unit throughput and the proportion

bypassed are controlled by on-line analysis of the gas

leaving the terminal. Effective management of the higher

H2S wells enables the unit to be bypassed at times

thereby lengthening the scheduled change-out intervals.

The PURASPECJM process has proved it has the flexibility

to handle significant variations in flow rate and inlet

concentrations of H2S with minimum operator attention.

Case study 3:

Successful sulphur and mercury removal from a dense-phase natural gas

The UK North Sea’s Central Area Transmission System

(CATS) terminal at Seal Sands on Teesside receives

gas that has high levels of natural gas liquids. It is

relatively sweet but contains small amounts of hydrogen

sulphide and mercury that must be removed.

Conventionally, raw gas would be split into different

hydrocarbon fractions with each being processed

separately. As this would require a large number of

reactors, a more cost-effective solution would be

to treat the gas as received under high pressure in

dense phase. The risk was that any phase separation

of gas and liquid hydrocarbons could lead to

flooding and channelling in a fixed bed system.

Because of the uncertainties about the behaviour of the

raw gas at the high pressure of 120 bar (1750 psi) and

the low temperature of 4°C (40°F), Johnson Matthey

were asked to install a small side-stream reactor. This

had provision for heating/cooling of the gas and operation

at reduced pressure. Even in runs when condensation

was taking place, there was complete removal of H2S.

This feed also contained mercury at difficult-to-detect

levels. It was simple to confirm that some of

the absorbents proposed for H2S removal

were also effective for mercury removal.

It was concluded that PURASPECJM technology was a

practical way to purify dense-phase gas, with the additional

attraction of providing a safe and environmentally

acceptable process requiring minimum operator attention.

The plant was completed on time and within budget and

began production in October 1997 and an identical

unit was successfully commissioned in October 1998.

Operation has been reliable and trouble-free, proving

that PURASPECJM treatment units offer a reliable low

pressure drop method for H2S and mercury removal from

dense-phase natural gas. Johnson Matthey manages the

change-outs and re-processing of the absorbent for BP

CATS via their PURASPECJM cradle to grave service.

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Case study 4:

Removal of H2S from

CO2- rich vent gas

Case study 5:

Propane sweetening

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ENI/Agip produces oil and associated gas in an

environmentally sensitive area of Northern Italy.

The CO2 rich gas is separated and passes through a

liquid redox system for H2S removal. Breakdowns in

this system were causing so much expensive loss of

production that the operator decided to install a two

bed PURASPECJM system as a back-up on account

of its flexibility, simplicity and ease of operation.

The PURASPECJM unit was installed during 1997.

It was first put into service because of a breakdown

in the redox system, for seven days in April 1998.

On-line analysis showed that, from an inlet H2S

concentration of almost 1%, the outlet was below

1 ppmv compared with the normal 5–6 ppmv.

When the redox system resumed, the PURASPECJM

process system returned to its stand-by duties.

Although PURASPECJM daily operating costs are

relatively higher, the operator recognizes the value of

the investment in terms of operability and efficiency

and as an insurance to protect against expensive loss of

production in the event of failure in the main system.

A major North American gas processing plant receives

raw gas sweetened to pipeline quality from several fields.

Here it is fractionated into dry gas, ethane, propane

and C4+

and sold to several downstream customers.

The propane is sold to a single petrochemical company

to a product specification of copper strip No. 1 quality.

This is assured by passing the propane through a single

bed of high activity PURASPECJM absorbent in a unit

commissioned in 1997. Sampling points throughout the

bed allow monitoring of the rate of consumption of the

absorbent, so that its replacement can be planned.

Although copper strip test results on the

propane stream before treatment vary,

the treated product has always

met the required specification.

This reliability has given the

operator confidence to

reduce the frequency of

copper strip tests from

daily to twice weekly.

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Case study 6:

COS Hydrolysis

There are two PURASPECJM products which can

be used in the COS hydrolysis process namely

PURASPECJM 2312 and PURASPECJM 5312.

The choice of absorbent depends on the temperature,

pressure and concentrations of other impurities

within the hydrocarbon stream. The design of the

purification unit for this application was based on

up 10 mg/m3COS and 41 mg/m3 H2S in the gas

stream. The total sulphur spec was < 5 mg/m3.

A bed of PURASPECJM 2312 was used to covert

the COS to H2S in one vessel followed by another

vessel for H2S removal. The operating data and

conversion rates were as shown opposite.

A European Gas terminal was designed to treat up to

86 MNm3/day of gas. The hydrogen sulphide (H2S)

in the incoming gas stream is partially converted

to Carbonyl Sulphide (COS) across the Molecular

sieve which is used to dry the gas. Since the gas did

not meet the gas sales specification of 5mg/nm3 of

total sulphur a PURASPECJM process was retrofitted

in 2005 to achieve H2S and COS removal.

The removal of COS is carried out by a two

stage process which involves the hydrolysis of

the COS and the subsequent absorption of the

H2S which is produced by this reaction.

0

00.00 01.00 02.00 03.00 04.00

10

20

30

40

50

60

70

80

90

100

Inlet

mg/

m3

COS hydrolysis - PURASPECJM 2312

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Case study 7:

Mercury removal from LPG

An Australian producer located on the NW Shelf,

found mercury in their propane and butane product

streams. Due to new product specifications they

required mercury removal from these streams.

Two PURASPECJM 500 vessels were installed

on the mixed LPG stream for mercury removal.

Each vessel is capable of 100% of the flow.

The beds were commissioned in 2005 and have

operated for over 2 years. They are still achieving

the required exit specification for mercury.

It is essential to remove mercury and its compounds

from hydrocarbon gases and liquids to avoid corrosion

of aluminium cryogenic heat exchangers, poisoning of

downstream catalysts and environmental problems.

The widely used method of removal is absorption by

sulphur impregnated carbon. However, it is not effective for

organic mercury, and sulphur can be lost by sublimation

or by leaching. Johnson Matthey recognized that ultra-

purification was only feasible if fixed beds were used and

an inorganic route taken to avoid sublimation and wetting.

Feed composition Propane and butane

Inlet Hq concentration 520 ppb w

Outlet Hq concentration < 0.5 ppb w

Operating temperature 48˚C

Operating pressure 13 bara

Position #3 30,000 bpd

Natural gas

Simultaneous removal of H2S and mercury from

natural gas was first demonstrated on a major gas

processing plant in the Netherlands. The dual purpose

absorbent reduced mercury to below its detection

level. During a scheduled shut-down in August 1995,

analysis of the spent portion of the bed showed that

the mercury was concentrated in the top 5-10%.

Dense-phase effectiveness

The application of fixed bed technology was developed

further for the treatment of dense-phase natural gas

from the North Sea. Extensive testing of Johnson

Matthey technology for mercury removal on a side-

stream reactor in 1995 showed that the process

would remove all mercury species present under

all conditions. This data enabled the design of units

which are now in service in the dense phase, achieving

the required sulphur and mercury specifications.

Natural gas liquids

Many commercial units for the treatment of natural gas

liquids are successfully operating. These commercial

units have been designed to treat propane, butane

and light and heavy naphtha streams intended as

feeds for catalytic reformers, thus protecting the

precious metal catalysts from poisoning and increasing

the value and marketability of the naphthas.

Mercury removal

Today, PURASPECJM absorbents are in world-wide

service removing traces of mercury, with or without

simultaneous removal of H2S, from feedstocks

ranging from natural gas to naphthas.

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Adding value to your plant

Solutions to protect people and the environment

Mercury is a toxic metal and has a relatively high vapour pressure. Consequently, on opening

mercury contaminated equipment, workers will be exposed to mercury vapour levels well

in excess of the Threshold Limiting Value (TLV) and the Maximum Allowable Concentration

(MAC). When mercury is detected more complicated tasks and plant procedures are

necessary and suitable personal protective equipment is required during maintenance work.

The European Union Scientific Committee on Occupational Exposure Limits proposes 0.02

mg/m3as an 8-hour time-weighted average and 0.01 mg/l in blood as biological limit values.

Unlike many other mercury removal solutions the PURASPECJM bed can be

located upstream of the dryers and of the acid gas treatment section of the

plant. Thus the PURASPECJM bed provides protection for much of the plant and

avoids the problems and costs associated with widespread plant contamination

and mercury emissions that have been encountered by many operators.

Process conditions

Flowrate 1.4 BSCFD

Pressure 112 Bara

Temperature 15 Deg C

Impurity Mercury - 5 µg/Sm3

Specification <0.01 µg/Sm3

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Reactor design

Traditionally the mercury removal reactors have used

axial flow designs. This allows for a simple design but as

pressure drop is of some concern it can lead to large

diameter vessels. Thus for a 50 m3 reactor the vessel

diameter is likely to be 5 m. Increasing the diameter

of the reactor results in thicker walls and restricts the

number of suppliers. Accordingly Johnson Matthey has

developed alternative designs. Radial flow reactors have

a much lower pressure drop and are less susceptible

to fouling. The vessels have more complex interiors but

the vessel diameter is reduced. Contra-flow designs

can be retrofitted into an existing flow design.

The savings possible with these designs

are shown in Figure 1.

* Radial flow designs ~ 5 time lower DP than axial

* Accessing the extra flow resultant from a lower DP can produce:

~ $1,6M revenue/day ($588M/year) or

~ £860,000 revenue/day (£314M/year) Assuming:

Gas spot price = $5.9 per MMBTU

Currency conversion $1 = £0.5338

Flowrate (Nm3/hr)

0

232515 465030 537381 694290 928720

200

400

600

800

1000

1200

DP

(mba

r)

Radial vs. axialVessel volume = 50m3

Axial Radial

The comparison has been made using the

design conditions given in Table 1.

Reactor size

Due to the high mercury pick-up of the PURASPECJM

material a smaller reactor size will be required for any given

duty when compared to many competing technologies

(e.g. carbon). This reduces both the Capex and the physical

footprint of the MRU (mercury removal unit). The physical

footprint being particularly important where space is

limited such as on offshore rig designs and revamps.

Table 1: Design conditions for pressure drop comparison

Component Mol%

N2 1.5

CO2 2.2

C1 851

C2 6.5

C3 3.0

C4 1.2

C5+ 0.5

Total 100

Pressure 60 bara

Temperature 25˚C

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The PURASPECJM process has proved it has flexibility to handle significant concentrations of H

2S and Hg

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Poisoning of catalysts

Expensive precious metal catalysts such as platinum and

palladium are particularly prone to poisoning by mercury.

They react to form a 1:1 amalgam i.e. PtHg or PdHg that is

stable at low temperatures used in hydrogenation. Levels as

high as 2000 ppm have been found on the top of 0.05%

palladium acetylene hydrogenation catalyst. Mercury can

be driven off by heating above 150 to 200°C but this

accelerates sintering and hence loss of active surface area.

Value of HC liquids with low mercury

Mercury does not fractionate with the heavier liquid

fractions in a natural gas plant as would be suggested

by it’s boiling point but tends to migrate into many of

the streams and is particularly prone to concentrate

into the liquid petroleum gas (LPG) fraction.

Just over half of the world’s 500 ethylene crackers use

naphtha feedstock, to avoid damage to the precious

metal ethylene purification catalysts a mercury

limit is set by the operators. So called “distressed

naphtha” is traded with difficulty and at $5 to $10/

tonne lower price than “open spec naphtha”.

Capital cost - bulk sulphur removal systems

Combining a PURASPECJM bed with a bulk removal system

(e.g. amine system) to remove H2S and COS allows the

operator to operate the amine system with a higher degree

of flexibility. This combined system allows greater levels of

sulphur slippage from the amine system in the knowledge

that the PURASPECJM bed will prevent the product stream

from going off-spec. The added bonus being that any

unplanned sulphur slippage from the amine system caused

by plant upset will not necessarily mean that the

operator will lose production whilst trying to

re-instate the amine system on-spec

conditions – the PURASPECJM

bed acting as a “catch all”.

The inclusion of a

PURASPECJM bed either

at the design stage or as

an uprate addition to an

existing plant provides

another degree of design

flexibility in designing the

acid gas bulk removal

system. A “trade-off”

can be made between

H2S and CO2 removal with

the knowledge that increased

amounts of H2S (and COS) from

the amine system can be removed

downstream by the PURASPECJM bed.

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PURACAREJM The complete service package

Performance guaranteed

The proven performance of our PURASPECJM

processes and our unrivalled experience enable

us to guarantee to meet the performance

standards agreed with the customer.

The expression ‘cradle to grave’ has been widely

adopted throughout production industries world-wide

and Johnson Matthey offer a unique package which

goes even further. PURASPECJM SM is a dedicated

service package designed to take care of all aspects of

operation, maintenance and absorbent/catalyst disposal

for our customers in the gas processing industry.

Under the expert direction of the gas processing

team, this hands-on service enables you not only to

save time and manpower, but also to comply with all

current and anticipated environmental legislation.

There is no such thing as a standard PURASPECJM

process. The choice of absorbent, catalysts and the

design of the reactor vessel will vary according to

the type of feedstock, the level of contaminants,

pressure and temperature conditions and the

pipeline or end-use purity specification.

PURASPECJM processes are operating effectively

in the temperature range 0-200°C (30-400°F),

pressures from atmospheric up to 120 bar (1750

psi) and flow rates exceeding 2.0 million Nm3/

hr (1.8 bscfd). Tell us your problem and we will

draw upon our wide experience to devise and

implement an individual solution. We will select from

the family of PURASPECJM processes or, where

necessary, develop a variation to meet your needs

precisely, regardless of the size of the application.

The scope of any PURASPECJM technology package

can also be tailored to your individual needs.

Johnson Matthey can offer the end user a full

engineering capability, supplying the full PURASPECJM

technology package, complete with detailed

engineering, piping and instrumentation specifications.

However, our flexible approach also enables us to

work with engineering companies - large or small

- or a customer’s own design team to deliver the

package you require. At its simplest a PURASPECJM

package can be the supply of the requisite absorbents/

catalysts together with operating instructions.

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The full cycle

As with the PURASPECJM package, we will

tailor the scope of PURASPECJM to meet your

specific requirements anywhere in the world and

it can cover the complete operating cycle.

Delivery and loading: we will manage the delivery of the agreed quantities and grades of materials to your plant, followed by loading using the most appropriate technique for the type of reactor vessel and site conditions. We will take responsibility for quality and reliability in every detail, from road haulage to fork-lift handling on site.

Optimum operation: we will advise you on how to make the most cost-effective use of our process in your plant. Our experienced and dedicated team will monitor your operation to ensure optimized performance. Towards the end of life we will provide recommendations on the timing for absorbent replacement.

Material discharge: we will provide trained people and suitable equipment to facilitate the clean and safe discharge of the used absorbents and catalysts, and transport them from site.

Environmentally friendly disposal: in today’s climate of environmental concern, our policy is to ensure the environmentally sound disposal of all our spent products. These often contain high concentrations of metals which makes recovery by smelting worthwhile. We audit smelting companies to ensure that they operate within their home nation’s environmental standards and frequently our customers also visit to ensure full compliance with corporate standards. We manage the whole process from unloading through transportation to the issue of a “certificate of destruction”, the final step in the life of a charge of absorbent.

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Services: The component that makes the difference

Johnson Matthey brings together three

critical areas to create a synergy which

results in a more powerful solution than you

could obtain taking them separately:

World-class products manufactured to ISO 9001 underpinned by a dedicated Research and Technology team developing products required to meet your ever-changing and demanding needs.

Applications know-how from a dedicated gas processing team with knowledge and experience in every facet of your operations combining years of our experience.

A full range of specialist services drawing on our expertise, designed to ensure you get the best from your plant.

Services applications know-how catalysts

Our close relationships with customers have

established the irreplaceable value of the services

part of the package in achieving the optimum

benefit from working with Johnson Matthey.

The gas processing team of specialists focuses

unique skills, acquired firsthand, on the practical

benefits that improve your plant operation.

Whether simple or complex, the services

required are an integral component

in realizing the full potential from

your operations. At different levels

in your operations, we can bring

to bear resources and expertise

from our manufacturing and

engineering operations.

Reliability

+ improved efficiency

+ increased production

= a more profitable business for you

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* This is not the complete PURASPECJM range of absorbents. Johnson Matthey representatives should be consulted to decide which is the most appropriate for any given duty.

PURASPECJM absorbent selector

For supply to the oil and gas industry there are two main series

of PURASPECJM absorbents. The PURASPECJM 100 series is for

removal of impurities from gas streams. The PURASPECJM 500

series is for removal of impurities from liquid hydrocarbon streams.

The absorbent type selected depends on the feedstock

composition and the impurity to be removed*:

PURASPECJM 1000 series

PURASPECJM

absorbent Impurity Feedstock Comment

1038 H2S natural gas, associated gas New generation S removal absorbent

1030 H2S natural gas, associated gas High capacity S removal absorbent

1020 H2S natural gas, associated gas S removal absorbent

1 57 Hg natural gas, associated gas Used when gas contains S

1 63 Hg natural gas, associated gas Used when no S present in the gas

PURASPECJM 5000 series

PURASPECJM

absorbent Impurity Feedstock Comment

1038 H2S LNG, NGL, Naphtha, condensate

Improved formulation providing very high S removal capacity

1030 H2S LNG, NGL, Naphtha, condensate Standard high capacity S removal absorbent

1020 Hg LNG, NGL, Naphtha, condensate Used when stream contains S

1 63 Hg LNG, NGL, Naphtha, condensate Used when no S present in stream

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BG

BP (in several locations)

Chevron

Conoco Phillips (in several locations)

DCP midstream

ENI

Exxon Mobil

Exxon Mobil North Sea

Khalda Egypt

Nigeria LNG

OMV Austria

OMV Pakistan

Petrocanada

Petronas Gas

Petroplus

PDO Oman

Saudi Aramco

Shell (in several locations)

Sirte Oil Libya

TAQA

Leadership in partnership

Johnson Matthey are the catalyst centre of excellence within the Johnson

Matthey group of companies, working with around 1000 customers in some

70 countries. As well as gas processing, we serve a number of related sectors

such as refineries, ammonia, methanol, gas to liquids and hydrogen.

Johnson Matthey are the catalyst centre

of excellence within the Johnson Matthey

group of companies, working with around

1000 customers in some 70 countries. As

well as gas processing, we serve a number of

related sectors such as refineries, ammonia,

methanol, gas to liquids and hydrogen.

Each of these markets has a Johnson

Matthey business unit dedicated to meeting

its needs. In gas processing purification our

experience and expertise are unrivalled.

The use of PURASPECJM absorbents

has expanded to a current level of

treating 80 million Nm3/hr (>7 billion

scfd) of natural gas and equivalent

volumes of hydrocarbon liquids.

Many of the major customers listed here

have worked in partnership with Johnson

Matthey to develop a PURASPECJM

process to meet their exact needs. We

also work closely with engineering and

construction companies who design

and build gas processing plants.

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