nitrogen generators - rjes – custom engineered...

RJ Engineering Systems designs and builds Nitrogen Generation Packages using

polymeric membrane systems from Air Liquide MEDAL®. The hollow fiber membranes

from MEDAL® offers one of the most efficient and durable nitrogen generation sys-

tems on the market. The Nitrogen Generator packages can be configured with equip-

ment for compressed air generation, pretreatment, membrane modules and down-

stream pressure boosting, as required by customers.

The operating pressure range of different membranes in combination with capacities

and pressure ranges of compressors available allows for a wide selection of package

models. Units offered in modular design provide the required flexibility in operation

per customer requirements. Specifications, standards, metallurgy and requirements

laid down by industry associations, major end users, engineering consulting

companies and inspection authorities are incorporated according to customer

demands.

Custom Engineered Solutions

RJ ENGINEERING SYSTEMS, INC

Nitrogen Generators

Membrane Type

MEDAL® hollow fiber nitrogen membranes are the most advanced in the world. The superior

performance of MEDAL® nitrogen membranes is derived from their high selectivity and high

productivity, which are a result of the ability to produce nitrogen membranes with an extremely

thin, defect free separating layer.

The range of MEDAL® membranes available have an output range of 5 to 5000 l/min and purities

of 95 to 99.95%, dry and CO2 free .

Nitrogen Generators using MEDAL membrane separators are typically of the composite type and

are more compact in size than those utilizing alternate technologies. This is a result of higher

nitrogen production per unit volume of membrane module. After aging of the membranes, the

nitrogen recovery ratio remains the same, with drop in production volume per membrane, at the

same time contributing to reduction in pressure drop across the membrane. The packaged units

are always sized to accommodate for the reduction in production volume after aging.

Membranes from MEDAL can tolerate high water content in the feed air. The membrane separator

performance will not decline permanently should water condense on the membrane surface.

Their performance reverts to 100% once the condensed water has dried.

The high H2O and CO2 permeability of the membranes ensures a very dry (-70 °C pressure dew

point) nitrogen product, depleted of CO2.

Membranes separate gases by the principle of selective permeation across the membrane wall.

For polymeric membranes, the rate of permeation of each gas is determined by its solubility in the

membrane material, and the rate of diffusion through the molecular free volume in the membrane

wall. Gases that exhibit high solubility in the membrane and gases that are small in molecular

size, permeate faster than larger, less soluble gases.

"Fast" gases permeate through the membrane wall faster or more readily than "slow" gases, thus

separating the original gas mixture into two streams. The purity of the desired streams can be

adjusted by changing the operating conditions.

The ability of a membrane to separate two gases is determined by its "selectivity", which is the

ratio of permeability of the two gases. The higher the selectivity, the more efficient the separation

and less energy is needed to run the system.

Based on operating pressures, the membranes are categorized as follows:

Low Pressure Membranes: For inlet pressures up to 15.0 barg/219 psig

High Pressure Membranes: For inlet pressures up to 36.0 barg/523 psig



Relative Permeation Rates

H2O He H2 NH3 CO2 H2S CH3OH CO Ar N2 CH4 C2H6 C3H8

Fast > > > > > > > > > > > Slow

Hollow Fiber Membrane Separators–Technology:

Compressed air supply to the Nitrogen generator is pretreated through a customized train,

depending on the quality of the compressed air. Wet compressed air from Oil flooded or lubricated

compressors go through a bulk coalescing filter to remove free water and oil droplets, followed by

a preheater to stabilize the relative humidity to 90% or less, to avoid wetting of the downstream

equipment. The heater is also designed to maintain an optimum process temperature conducive

to maximum recovery rates and flow capacity. An Activated carbon bed filter removes oil aerosols

and vapor, with a 0.1 micron particulate filter downstream of heater to ensure long uninterrupted

life of the membranes.

Pretreatment systems for compressed air supplied from oil free compressors can be limited to a

coalescing filter and heater. Activated carbon filters are not needed unless ingress of

hydrocarbon vapors are anticipated.

In Low Pressure Membranes, the cleaned, superheated

compressed air enters one end of the membrane bundles

with sealed off inter fiber voids, the gas flow is through the

inside or bore of the hollow fibers. Permeates or rejects

consisting of O2, CO2 and water vapor permeate to the

outside of the membranes and are exhausted to the

atmosphere, through side vents. Nitrogen at purity as

controlled is delivered at the other end of the membrane

bundles through the bores.

In High Pressure Membranes, the flow pattern is the

opposite, with the gas flow on the outside of the hollow

fibers, with the permeates travelling to the bore of the

fibers. Nitrogen is delivered through a channel at the

center of the bundle on the same side as the inlet.

Permeates are directed from the cores to a vent port on

the opposite side to be vented to atmosphere. This ar-

rangement provides for very low pressure drops, which

are critical for high pressure operations.

Overall, MEDAL membranes offer very little pressure drop due to design of the fibers; the pressure

drops reduces further as the membranes age over time. In high purity flows, the pressure drop

can be as low as 0.06 bar/0.9 psi to 0.4 bar/5.5 psi, depending on the membrane model

selected.

Nitrogen purity and flow is controlled by a pneumatic flow control system comprising of an

intelligent back pressure control valve with a positioner, with an override based on the output

from the Oxygen analyzer. This arrangement allows for continuous operation of the system without

any manual adjustment of the back pressure valve , when process variables change due to

variations in ambient conditions, process demand or upstream equipment performance.



Membrane Type Nitrogen Generators-Process Description:

Membrane Type Nitrogen Generators are designed to operate continuously at maximum design

rate but can seamlessly adapt to fluctuating demands across the full range. If the demand goes

down, the system shuts off the inlet gas flow at an adjustable discharge pressure set point until

the demand picks up again; the nitrogen supply resumes immediately on demand.

The modular construction allows modifying the capacity of the system by isolation of one or more

membrane bundles, if needed to adjust the real time size of the unit. This feature allows online

replacement of the bundles as well, without affecting production.

The unique dual blowdown system in the design of the package allows automatic streamlining of

the nitrogen generator during startups and resets, without any deterioration of purity of nitrogen

in the downstream storage or piping. The system adds the safety feature of instantaneous

evacuation of the membranes, in case of upstream upsets like malfunction of compressor after

cooler or heaters.



Membranes housings are available from a select choice of materials: Aluminum, Carbon

steel or Stainless steel. The carbon steel and stainless steel housings are designed to ASME

Sec VIII Div 1 and certified.

Piping is designed as per applicable piping standards including ASME B 31.3. Stainless

steel or Carbon steel piping, valves and vessels are available as per installation locations

and operating conditions. Vessels are designed to ASME Sec VIII Div 1 and certified.

Heater element sheaths in Incoloy 800H, SS 321 & SS316L

Radiography, Ultrasonic & Dye Penetrant Inspection available for all components

Full traceability and Certification to EN 10204 2.2, 3.1 or 3.2 as required.

Membrane Type Generators-Design & Operation Flexibility:

Membrane Housings, Vessels and Piping-Construction & Materials:

Special Features :



Intelligent and Flexible Control Systems

Microprocessor based programmable control

systems with Graphic interfaces, with flexibility to

allow user programming and full remote

connectivity.

Programmable Logic Controllers which form the

core of the controls can integrate upstream and

downstream equipment for total package control.

Standard construction has Stainless steel panels-

NEMA 4X/IP 66 protection with touchscreen HMI.

The HMIs have full onscreen diagnostic capability

and energy buffering for data security.

The panels are suitable for locating in harsh envi-

ronments, with basic units supplied with UL Class 1

Div 2 or ATEX Zone 2 and 22 approvals.

SCR Controlled Heaters

Electric air pre-heaters use SCR power controllers

with dedicated heater panels, as standard. The

heater panels come standard with safety features

like Shorted SCR detection, Flange temperature

cutouts, Element temperature cutouts and Panel

temperature cutouts.

Standard diagnostic features include individual

Current, Voltage and Power measurements, Partial

load detection and Earth leakage detection.

Heater designs incorporate two options: Hairpin

type elements for compact installations and

Straight cartridge elements which allow online

maintenance and change-outs with 100%

redundant element sets.

Integrated Packages

The large range of air compressors and boost-

er compressor options from RJ Engineering

portfolio makes integrated packages with

upstream and downstream compressors

possible.

Apart from reduced capital costs due to

consolidated engineering and manufacturing,

this allows single point monitoring of

operation by global controls. An integrated

package can contribute towards considerable

savings in operating costs, especially in cases

with fluctuating demands.

Interactive sizing of components and capacity

control by variable speed are some of the ways

integrated packages offers energy savings.

Customization options :



Hazardous area classification

Units are configured to meet hazardous area

classification requirements to fit project spec-

ifications.

Heaters, Instruments, Cables, Glands & Panels

are selected to meet requirements of NEC, NFPA

70/IEC 60079/ATEX Directive 94/9/EC

explosion proof and intrinsically safe classes,

zones, categories, gas groups and temperature

classes, beyond the Class 1 Div 2 & Zone 2 and

22 standard approvals.

When Integrated packages are offered, Electric

motors and local starter panels including

variable Frequency Drives can also be area

classified. Heater SCR panels can also be

customized with explosion proof purge units, if

located in the field.

Outdoor units-Weather protection & Portability

Weather proof enclosures and construction for

all- weather outdoor operation is another special-

ty offered across all units. The package would be

enclosed in a portable weatherproof container

with all- weather insulation and HVAC for equip-

ment protection and personnel comfort. Typical

all weather units are designed to operate

between average low (-32°C/-25°F) to average

high (46°C/115°F) and protected against rain,

snow, sleet and dust.

Portable units can be designed to be self con-

tained, with air pre-heaters & space heaters

utilizing engine jacket water as the heating

medium.

Special metallurgy for components

Custom material grades and specialty coating are

available on all components, for harsh operating

environments like offshore, coastal, humid and

dusty locations. Stainless steel piping and vessels

are offered with internal and external grit blasting,

polishing or special coating, depending on the loca-

tion and service.

Instrument wetted parts in Hastelloy C & Monel 400,

Stainless Steel 904L or Inconel 625 tubing,

Stainless steel cable glands, fittings & explosion

proof panels are some of the unique metallurgical

requirements addressed in custom packages.

XNML&H1/2/3/4-****-9950/9900/9800/9700/9500: Membrane Module Packages

TECHNICAL SPECIFICATIONS—INDIVIDUAL MEMBRANE MODULES



*Custom sizes to meet total flow capacities, depending on the number of membrane modules installed. Flow rates shown are per membrane module at the maximum continuous operating temperature and maximum working pressure.

Recovery rates improve at lower temperatures (min recommended @ 35°C/95°F) but with lower flow capacities.

Model Number Module

Type

Max Feed Pressure

Inert Purity

(N2+Ar)

Flow Rate/module @ Max Pressure Pressure Drop

Barg Psig

Product

(N2+Ar) Feed Air

Product

(N2+Ar) Feed Air

Bar Psi

Nm3/hr CFM

LOW PRESSURE MEMBRANES ( @60°C/140°F Operating Temperature)

XNML1-*-9995 4121 15 219 99.95% 0.3 4.3 0.2 2.7 0.11 1.6

XNML2-**-9995 4241 15 219 99.95% 2.3 20.3 1.4 12.6 0.38 5.45

XNML3-***-9995 4640 15 219 99.95% 10.2 91.3 6.3 56.8 0.35 5

XNML4-****-9995 4240 15 219 99.95% 33.5 308.9 20.8 192.1 0.29 4.24

XNML1-*-9990 4121 15 219 99.90% 0.5 4.5 0.3 2.8 0.12 1.75

XNML2-**-9990 4241 15 219 99.90% 3 21.1 1.9 13.1 0.4 5.84

XNML3-***-9990 4640 15 219 99.90% 13.3 95.1 8.3 59.2 0.37 5.35

XNML4-****-9990 4240 15 219 99.90% 43.7 321.4 27.2 199.9 0.31 4.54

XNML1-*-9950 4121 15 219 99.50% 1.1 5.4 0.7 3.4 0.16 2.3

XNML2-**-9950 4241 15 219 99.50% 5.7 24.5 3.5 15.2 0.51 7.46

XNML3-***-9950 4640 15 219 99.50% 25.7 110.5 16.0 68.7 0.47 6.81

XNML4-****-9950 4240 15 219 99.50% 85.5 373.6 53.2 232.4 0.39 5.78

XNML1-*-9900 4121 15 219 99% 1.7 6.1 1.1 3.8 0.19 2.76

XNML2-**-9900 4241 15 219 99% 8 27.3 5.0 17.0 0.6 8.78

XNML3-***-9900 4640 15 219 99% 35.7 123 22.2 76.5 0.55 8

XNML4-****-9900 4240 15 219 99% 119.3 416.4 74.2 259.0 0.47 6.8

XNML1-*-9800 4121 15 219 98% 2.6 7.2 1.6 4.5 0.25 3.55

XNML2-**-9800 4241 15 219 98% 11.7 32 7.3 19.9 0.76 11

XNML3-***-9800 4640 15 219 98% 52.4 143.8 32.6 89.4 0.69 10

XNML4-****-9800 4240 15 219 98% 176.1 488.3 109.5 303.7 0.59 8.53

XNML1-*-9700 4121 15 219 97% 3.4 8.2 2.1 5.1 0.29 4.21

XNML2-**-9700 4241 15 219 97% 15 35.6 9.3 22.1 0.89 12.9

XNML3-***-9700 4640 15 219 97% 67 160.1 41.7 99.6 0.8 11.7

XNML4-****-9700 4240 15 219 97% 225.6 543.7 140.3 338.2 0.69 9.96

XNML1-*-9500 4121 15 219 95% 5.1 10.1 3.2 6.3 0.38 5.57

XNML2-**-9500 4241 15 219 95% 21.6 42.9 13.4 26.7 1.15 16.7

XNML3-***-9500 4640 15 219 95% 97.1 192.8 60.4 119.9 1.05 15.16

XNML4-****-9500 4240 15 219 95% 327.8 655.3 203.9 407.6 0.89 12.9

HIGH PRESSURE MEMBRANES ( @60°C/140°F Operating Temperature)

XNMH1-**-9900 G6MP 36 523 99% 66.6 192.6 41.4 119.8 0.06 0.9

XNMH1-**-9800 G6MP 36 523 98% 79.2 207.5 49.3 129.1 0.08 1.2

XNMH1-**-9700 G6MP 36 523 97% 103.7 235.8 64.5 146.7 0.13 1.9

XNMH1-**-9500 G6MP 36 523 95% 156.7 287.6 97.5 178.9 0.17 2.5

RJ Engineering Systems, Inc

13805, West Road

Suite 350

Houston, TX-77041

USA

Tel: +1-281-897-0350

Fax: +1-281-897-0355

E-mail: [email protected]

www.rjesusa.com



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nitrogen generators - rjes – custom engineered...

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