IK sootblower is a device that removes ash and carryover deposits from inside the furnace. This type of a sootblower has a long retractable lance with nozzle(s) at the end. The steam flows through the lance and out of the nozzle(s) spraying steam onto the furnace components, knocking down the deposits. Depending on the width of the boiler, either one sootblower is installed in a lane on one side of the boiler and is long enough to clean the entire width of the furnace, or there are two sootblowers installed in one lane on opposing sides of the boiler, each cleaning half width of the boiler. It is common to have anywhere between 30 to 120 sootblowers in a typical recovery boiler, depending on the boiler's size.

During a shutdown, IK sootblowers are usually locked out and as such are safe to access and inspect. Gloves are recommended for inspection. Grease, oil, sharp surfaces are commonly encountered around these sootblowers.

During an operation, increased caution is required as IK sootblowers can be quite dangerous. They use a hot and pressurized steam for cleaning. Sootblowers are remotely operated and 'start without warning'. It is not uncommon to have leaking flanges and wallboxes and a hot steam may start flowing out of the sootblower components unexpectedly. IK sootblowers also have rotating equipment, gears, and other components. 'Never touch, walk under or near IK sootblower while the boiler is in operation, even if the sootblower is not running.'

IK sootblower consists of the following systems:

• Sootblower Lance
• Poppet Valve
• Steam Flanges
• Packing Gland and Feed Tube

• Motor
• Actuating Arm
• Gears and chain
• Rail
• Rollers

• Limit Switches
• Manual Pressure Gauge

• Canopy
• 'Pumpkin Head'
• Seal Plate

Usually a slightly superheated or saturated steam is used as a cleaning medium for IK sootblower. The steam either comes directly from the steam drum, or downstream from the superheaters, or from headers. The goal is to have the steam leave the superheater nozzle at high velocity and condense at this moment. The condensed water droplets have higher density and thus higher cleaning power than steam (but also higher erosion on boiler components).

Steam enters the sootblower through a poppet valve that is operated by an actuating arm. When the sootblower starts to rotate and goes inside the furnace, an actuating arm meets a trip stud which pulls the lever on the arm and this opens the poppet valve and steam starts flowing. When the sootblower is idle, the poppet valve is closed, however it is not uncommon for these to slightly leak. If that happens, steam enters the lance and it condenses. As such during the idle time, the lance is filling up with water. The nozzle should have draining holes drilled around that should drain this condensate when the sootblower is idle. Properly installed sootblower is tilted slightly downwards towards the boiler for this reason of draining the condensate. It is however important to remember that the boiler expands downwards during operations, as such the sootblower will be tilted differently during the operations than it is during a shutdown.

• Trip stud mounted on the assembly
• IK lance nozzle and drain holes

Sootblower is mounted on outboard side to the building. On the inboard side it is mounted to the boiler. However, due to the fact that the boiler expands during operations while the building is stationary, the outboard mount is done through some kind of a pivot rod or other mechanism to allow for this movement.

• IK mount to the building through a pivot rod

Sootblower penetrates the boiler through a wallbox. There are different types of wallboxes. The wallbox has a 'pumpkin head' mounted on it. Sooblower lance is inserted into the pumpkin head and mounted on it. Seal plate is mounted around the lance to seal the interface between the inside of the furnace and the boiler building. When the sootblower starts operating, the motor pushes the sootblower into the furnace. At one point, poppet valve opens and steam starts flowing. The timing of the opening of the poppet valve is usually done so the steam starts flowing when the nozzle is between the furnace side wall and the first tube in its path. This is done in order to prevent erosion caused by accumulated condensate in the lance. Once this condensate is clear, the steam flows out of the nozzle and cleans the components. If the poppet valve opens too early, accelerated wall box deterioration may happen. If the poppet valve opens too late, erosion on the boiler components may happen.

• Damaged tube by sootblower
• Damaged casing and wallbox

In order to prevent corrosion of the nozzle, wallbox is purged by air or steam. A connection from the poppet valve or a separate air connection is wired into the pumpkin head near the wallbox. As the steam or air flows into the wallbox, it is slightly pressurized and keeps the combustion gases away.

Numerous deficiencies can be found with the IK sootblower.

* When inside the furnace and when the sootblower is fully retracted, the sootblower lance and nozzle should be fully positioned inside the wall box. No part of the sootblower should be protruding past the wall box. If that is the case, the nozzle can be subjected to harsh flue gas environment and can corrode or burn out. Check for cracks, corrosion, or damage to the lance head and the nozzles.

• Sootblower in the wallbox
• IK lance head burnt out in the wallbox
• IK lance head burnt out in the wallbox
• Cracked IK lance head
• Protruding lance

The wallbox is an opening in the furnace with a sleeve through which the lance moves. Sometimes the wallbox has metal plates welded to the tubes to protect the casing. The metal plates, the sleeve, and the wallbox are subject to corrosion. If the sootblower lance collects condensate when idling, all of this condensate can drip on any of these components causing corrosion or even cracks. If the poppet valve opens too soon, the steam and condensate can damage the wallbox also. Check for cracks in the crotch plates, check for damage to the wallbox tubes caused by erosion.

• Crack in the wallbox crotch plate
• Corroded wallbox
• Damaged wallbox
• Crack in the crotch plate

The sootblower lance head has holes drilled around to allow draining of the condensate from within the lance. If accessible and visible check that the drain holes are not plugged.

The sootblower poppet valve is supposed to open when the lance travels and is just between the boiler sidewall and the first tube of the boiler component such as superheater, economizer, or generating bank. Always check the first few tubes for signs of erosion or corrosion from the sootblower.

• Crack in the wallbox crotch plate
• 'Elephant Hide' damage on tube cause by sootblower

The path the sootblower travels should be clear and there should not be any tubes in the way. Damage can occur if the sootblower physically rubs or hits any tubes in its path every time it travels. Check all tubes at the elevation of the sootblower for any mechanical damage.

• Check for loose or missing bolts in all flanges* (steam piping flange, feed tube flange)

• Loose bolts

Check the packing gland, bolts, and that it is tight.

• Missing bolt in the packing gland follower
• Blown packing

Check the poppet valve. There is a spring on top of the valve and it should be intact. There should be a stem inside the spring. The top of the spring should be secured with a washer and a pin. The actuating arm should be resting on top of the stem. You should be able to move the actuating arm and open the valve with your hand. There should be quite a tension but not enough that you can't move it. It shouldn't be too loose either.

• Missing pin

Check the wallbox purge system This can be either steam or a separate air system. If steam, check all the lines, and connection to be tight and secure. If air, check all the hoses and clamps.

• Loose steam purge line
• Torn air purge hose

Check the gear rail. Rail can be broken, damaged, or most likely worn.

• Gear rail in good condition
• Worn rail

Check all electrical connections. Check that all electrical cables are secure and properly connected. Also check that the ground wire is in place.

• Disconnected junction box

Check the actuating arm and pin stud. The pin stud should be firmly secured on the arm and it should not be bent.

• Missing trip stud
• Bent trip stud

Check the rollers. Rollers should be tight and properly oriented. There should not be any gap between the roller and the lance.

• Roller not contacting lance

Check chains, sprockets, and gears. If this is a chain driven sootblower, check for tightness of all sprockets and tightness of the chain.

• Loose chain

Check all limit switches There are always two. One on the inboard side that sends signal when sootblower is fully retracted and one on the outboard side when fully inserted. The limit switches are either magnetic or mechanical.

• Magnetic limit switch
• Loose limit switch

Check the wallbox seal plate. The seal plate is sometimes missing, sometimes loose, corroded, bent, out of position etc.

• Missing seal plate