Moss Inert Gas Generator System
for Gas Carriers

Hamworthy Moss

Moss Inert Gas Generator

System for Gas Carriers

The unique design is based on

experience from a large num-

ber of installations, the first

one in the late 1960`s. High

efficiency, low maintenance

costs, easy and safe operation

combined with minimum

space requirements are impor-

tant features of the Moss

design. This is reflected in the

overall layout, the choice of

materials / corrosion protec-

tion and the control system.

Special features

The Moss Burner/Scrubber

Unit requires less deck space

than any other known design.

This is due to the location of

the combustion chamber con-

centrically inside the scrubber

unit. Other benefits of this

design are that the unit does

not require any special directi-

on of orientation inside the

ship and that the inert gas

quality will not be affected by

the ship’s rolling and pitching.

High inert gas purity with a

very low content of crystalline

salts is the measurable outco-

me of this design.

The unique Moss High Turbu-

lent Burner ensures an almost

complete combustion with a

rugged simple design and no

moving parts. For systems

requiring inert gas with less

than 1% O

2

, fresh water may

be injected into the combusti-

on air. This will reduce the

NOx and CO level in the inert

gas.

Heat/corrosion resistant steel

is used for all surfaces expo-

sed to heat and/or sea water.

The Blower Units supplying

combustion air are of the

Roots type with electric

motors, arranged on a rigid

steel base frame equipped

with resilient mountings.

The inert gas drying is done

in two stages. In stage one

the inert gas is cooled down

to 5ºC or less removing most

of the water. In stage two the

gas passes through an absorp-

tion drier with two chambers

filled with desiccants (Al-

oxides). This process brings

the dew point down to the

required level, usually -45ºC.

The two chambers are active

one at a time. While one

chamber is absorbing the

other is being re-generated

through heating. Electric

and/or steam heating is

available.

For smaller systems the drying

may be of the heatless type.

In this system the inert gas is

compressed to around 7 bar g

removing most of the water

by means of cyclone filters.

The gas then passes through a

pressure swing absorption

drier with two desiccant

chambers. The regeneration

of the absorbent is achieved

by releasing the pressure in

one chamber while the other

is absorbing.

The Control System is based

on a Programmable Logical

Control (PLC). The control

panel has a mimic flow

diagram and the controls

required for safe and easy

operation of the plant with a

minimum of operator super-

vision.

A design based on handy

modules means that the Moss

Inert Gas Generator System

offers important savings in

space and installation costs

both for newbuildings and for

retrofit on existing vessels

Performance data

Normal outlet drier pressure: 0,25 bar g.

Other pressures upon request.

Inert Gas composition

at 1% by volume of oxygen

(based on marine distillate fuel).

CO

= Max. 100 ppm

NO

x

= Max. 100 ppm

SO

2

= Max. 1 ppm

CO

2

= Approx. 14%

N

2

+ Ar = Balance

Oxygen content adjustable down to

0,5% O

2

.

Gas outlet temperature:

Max. 5ºC above sea water temperature.

Dewpoint after drier normally down

to -45ºC.

(Average at atm. press.)

Fuel: Marine distillate according to

ISO 8217.

Nominal fuel consumption:

0,084 kg/Nm

3

gas.

Nominal sea water consumption:

0,075 m

3

/Nm

3

gas

(sea water temp. 32ºC and incl. cooling

plant condenser).

Nominal el. power consumption

excluding sea water pumps:

0,04 kW/Nm

3

/h gas

(0,06 if el. heater in operation)

ref: HMO 4002 0105/1

Hamworthy Moss AS
P.O. Box 1053
NO-1510 Moss
Norway

tel: [phone]
fax: [phone]
e-mail: [e-mail]
web: http://www.hamworthy.com

A subsidiary of Hamworthy plc

The manufacturers reserve the right to alter the
specification and data to incorporate improvements
in design. Certified drawings will be issued on request.

© All details copyright Hamworthy plc.

Certificate no.: NO-800121