Techne FSSR1 User manual

Issue 1
02/07
FSSR1
Venturi Scrubber Unit
OPERATOR’S MANUAL

Contents
Section Page
1. Introduction 1
2. Installation 1
3. Start-Up 1
4. Normal Operation 1
5. Shut-Down 2
6. Maintenance 2
7. Suggested Spares 2
Appendix 1 Scrubber Layout Drawing
Appendix 2 Operating and Maintenance Instructions for Pump

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1. Introduction
The scrubber is a Venturi scrubber designed to recirculate water to remove
fumes from a gas stream. The primary design of the scrubber is the removal of fumes
from a furnace installation however, it can be used for a wide variety of applications.
Absorption of fumes is achieved in the spray venturi contact with scrubbing liquor
recirculated by a sump pump from the column sump tank.
A General Layout Drawing of the unit is included in the documentation manual.
2. Installation
The scrubbing unit should be sited on a level surface. It is recommended the base frame
be through bolted to the floor.
The gas inlet and outlet are of plain spigot arrangement, the connecting flexible duct
should be secured with jubilee type clamps.
The scrubber should be connected to a water supply. The connection is a ½” BSP female
threaded connection as labelled, it is generally recommended an isolation valve be fitted
in the water supply to the scrubber.
The drain connection may be connected to a suitable drain. This is not essential as liquid
should not be discharged during normal operation.
The pump should be connected to a single phase 240V supply. DO NOT RUN DRY.
3. Start-Up
Following installation or a shut-down period the integrity of the scrubber unit should be
visually checked.
The position of valves should be as follows: Drain Valve :Closed
Sampling Valve :Closed
Recirculation Valve :Open
The water supply can then be turned on to the scrubber and allowed to come up to level.
The scrubber is fitted internally with a ball float valve, this will maintain the correct liquid
level in the scrubber.
Once the liquid level has reached operating level the pump can be switched on and the
system inspected for leaks.
NOTE: DO NOT OPERATE THE PUMP WITH NO WATER. RUNNING THE PUMP DRY
WILL CAUSE SIGNIFICANT DAMAGE.
Having ensured there no leaks, the unit is ready for normal operation.

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4. Normal Operation
Note:
Prior to operators carrying out any work on this unit, they must be advised of the
hazardous nature of the chemicals involved and the emergency procedures to be
followed in case of personal exposure.
The sump should be filled with the appropriate scrubbing solution. The unit is designed
for using fresh water, however caustic soda may be added through the level gauge to
improve scrubbing performance (normally a 5% Caustic Soda solution). The level in the
sump will fall slightly due to the water in the pipework but will be made up automatically,
this is normal and the operating level should be noted.
The scrubber is now ready for use. The air stream containing the fume to be removed can
be vented through the scrubber.
Over a period of time the recirculation liquid will suffer evaporative losses, the operating
level will be maintained by the automatic addition of water.
As the scrubber absorbs and neutralises fumes, the scrubbing solution will become
contaminated or, if added, chemical in the scrubbing solution will be used up. The fluid
should be checked on a regular basis to maintain the optimum efficiency of the unit. As
necessary, scrubbing liquor can be bled to drain from the drain valve, being made up
automatically with fresh water, or more caustic added. Continuous addition of more
caustic will cause salt build-up and possible crystallisation causing damage, it is therefore
recommended to occasionally drain down the scrubber and refill with fresh water.

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5. Shut-Down
If the scrubber is to be shut-down for inspection, cleaning, or for any other reason the
sump should be flushed with fresh water several times to remove any chemical residues.
The make-up water should be isolated and the sump drained through the drain valve. The
pump should not be allowed to run dry.
The lid of the scrubber can then be removed and any remaining deposited solids
removed.
6. Maintenance
Other than the maintenance of the pump, refer to appendix 2, the scrubber will need little
regular maintenance.
The internal assembly is simple and strip down for inspection straight forward.
•Turn off and drain the scrubber tank.
•Remove the recirculation pipe by splitting the unions at the venturi and above the
pump.
•Unbolt the two pairs of metal flanges and remove the venturi.
•Unbolt the tank lid and lift out.
•Lift out the upper mist eliminator grid and eliminator pad.
•Re-assembly is reverse of removal –carefully ease the inlet pipe through the
eliminator pad.
The unit should be regularly checked for leaks and these should be rectified immediately.
Inspect the internals on an regular basis to check for any damage or deterioration.
Should the spray nozzle become blocked it is removed by unbolting the flanges above
and below the venturi, disconnecting the recirculation pipe and removing the venturi
assembly. The nozzle is unscrewed using a box or basin spanner from the lower end of
the venturi throat.
7. Recommended Spares
For 2 years operation we would recommend the following spare parts are kept;
a) Demister Pad
b) Pump
c) Float Valve
Miscellaneous gaskets and fastenings

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8. Additional Notes –Following Site Inspection June 07.
Usage of the scrubber is currently un-quantified so inspection and testing routines should be
more frequent until appropriate routines are established. It was noted during the site
inspection that large quantities of solids were being deposited in the scrubber and it may be
solid deposition rather than chemical levels that determine flushing cycles.
The scrubber is mainly designed to deal with HCL gas which is easily water soluble. Precise
control of chemical concentrations and levels is not required. HCL dissolved in fresh water
turns it acidic, the more acidic the recirculation liquor in the scrubber the less efficient it will be
at the removal of HCl. Addition of alkali caustic soda reacts with the HCL in the liquor to
lengthen the time the scrubber remains efficient. Continuous addition of more caustic will
cause salt build-up and blocking of the scrubber, the scrubber content should be drained and
refilled with fresh solution to prevent this. Monitoring of the state of the liquor can be simply
carried out using litmus paper or equivalent.
The caustic solution concentration is not critical, we would recommend below 15% and state
5% as a nominal value.
Caustic soda reacted with HCL gives common salt, provided the pH is neutral the scrubber
liquor should be fit to dispose down the drain, however this takes no account of any other by-
products of the furnace. This should be determined by chemical testing.
The problem of scaling due to hard water was raised. Caustic solution will exacerbate this
problem. However the scrubbing system is resistant to chemical attack so can be descaled
using a mild acid solution (or allowing the scrubber liquor to become acidic).
For the purposes of cleaning, the inside of the scrubber can be pressure washed. The mist
eliminator pad should be gently manipulated to aid solid break up and then pressure washed.

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Appendix 1
Scrubber Layout

A3

Appendix 2
Operating and Maintenance Instructions for Pump

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