How to Do a Repair of Refractor Lining

INSTRUCTIONS FOR REPAIR OF REFRACTORY LINING In case of damage to the refractory lining inside the incinerator, repair work can be carried out by following these guiding instructions. Major repairs can be carried out by Atlas Incinerators A/S by means of formwork and casting or with ramming material, or by using prefabricated refractory bricks. Atlas Incinerators A/S is normally able to supply materials needed for repairing the refractory as by request. The two partition walls separating the combustion chambers will normally be replaced completely by using bricks, if they are considered to be under Repair type 3. Please contact Atlas Incinerators A/S for information, or contact a company specialized in refractory lining, if any doubt. Before preparing for any repair work, the power supply for the incinerator must be disconnected !

Repair types When inspecting the lining, decide between 3 different extents of damage : Repair type 1 : Damaged area of less than 4 cm³. Cracks of 3 - 5 mm. Repair type 2 : Damaged area of 4 – 100 cm³. Cracks of 5 - 20 mm. Repair type 3 : Rebuilding a full-sized refractory wall.

Repair type 1 • Clean the damaged area for deposits and loose particles. • Cover the area with an air setting mortar, or a fine grain coating (grain size 0.5 mm) with approx. 45% aluminium oxide (Al2O3), low iron content and a temperature limit up to 1500 °C. • Refer to instruction from the supplier regarding mixing and application. • If supplied from Atlas Incinerators A/S, the material name is ALOGUN. Repair type 2 • Clean the damaged area for deposits and loose particles. Plastic covers • Insulation material towards the steel plate is exchanged. • Burnt out steel anchors are exchanged. Remember plastic covers. Steel anchor Anchors are needed to support the refractory. • Cover the area with ramming material with approx. 45-50 % aluminium oxide (Al2O3), low iron content, grain size up to 6 mm and temperature limit up to 1500 °C. • Refer to instruction from the supplier regarding mixing and application. • If supplied from Atlas Incinerators A/S, the material name is ALOPLAST. • The ramming material is formed into balls of approx. 50 mm in width, and they are rammed into position in the repair spot. Continue this work, until all repair spots are covered.

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Repair type 3 • Clean the damaged area for deposits and loose particles. • Insulation material towards the steel wall is exchanged. • Burnt out steel anchors are exchanged. Remember plastic covers. • Formwork is set up, and casting material is added. • Material properties should be as described for Repair type 2. • Refer to instruction from the supplier regarding mixing and application. • If supplied from Atlas Incinerators A/S, the casting material name is ALOCAST. • A full-sized wall can also be rebuilt by using ramming material only (see Repair type 2). • If supplied from Atlas Incinerators A/S, the ramming material name is ALOPLAST. • In case the repair area is larger than 300 x 300 mm, steel anchors are welded onto the steel plate at intervals of 250 – 300 mm. Anchors are needed to support the refractory. • Steel anchors can be supplied by Atlas Incinerators A/S as by request.

Drying-out After repair, the refractory needs to be dried out to remove moisture in the material. Contact Atlas Incinerators A/S for how to run a drying-out program for the incinerator. Then follow these procedures for heating up the incinerator.

Repair type 1 and 2 ○ Air-drying for at least 12 hours at a temperature above 10 °C, and at least 24 hours at a temperature of 5-15 °C. Newly repaired refractory must never be exposed to frost. ○ Heating up to 200 °C in 5 hours, with a rise of 40 °C per hour. ○ Temperature of 200 °C is obtained for 2 hours. ○ This procedure is also valid for partitions walls rebuilt with bricks. Repair type 3 (casting) ○ Air-drying for at least 12 hours at a temperature above 15 °C and at least 24 hours at a temperature of 5-15 °C. Newly repaired refractory must never be exposed to frost. ○ Heating up to 200 °C in 5 hours, with a rise of 40 °C per hour. ○ Temperature of 200 °C is obtained for 12 hours. ○ Heating up to 400 °C in 3 hours, with a rise of 60 °C per hour. ○ Temperature of 400 °C is obtained for 12 hours. After rebuilding a complete set of walls in the incinerator ○ Air-drying for at least 12 hours at a temperature above 10 °C, and at least 24 hours at a temperature of 5-15 °C. Newly repaired refractory must never be exposed to frost. ○ Heating up to 200 °C in 5 hours, with a rise of 40 °C per hour. ○ Temperature of 200 °C is obtained for 36 hours. ○ Heating up to 400 °C in 3 hours, with a rise of 60 °C per hour. ○ Temperature of 400 °C is obtained for 24 hours.

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Partition walls The illustration below shows the big and small partition walls. If rebuilding these walls with refractory bricks from Atlas Incinerators A/S, this will be the design. The two walls fit into each other. Small partition wall Big partition wall

15 17

16

18

12

14

19

9

11

6

8

13 10 4 7

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2 3 1

■ Break down existing partition walls. Remove old steel anchors for the small wall. ■ Soft insulation material towards the steel plates is exchanged. ■ Before starting the mounting of bricks, check the vertical installation dimensions. Allow for repair material (ALOGUN) below the bottom bricks, and above the top bricks. ■ The bricks are fitted together, starting with no. 1. ■ No. 15 and 17 are held up towards the ceiling, while 16 and 18 are fitted in below. ■ Mortar material (ALOMOR) is used between the bricks on top and bottom surfaces. ■ Repair material (ALOGUN) is injected into the vertical holes and spaces between the bricks. For the top bricks, it might be necessary to dismount the mixing chamber (flue gas outlet) and use access through the ejector opening. ■ Repair material (ALOGUN) is filled into spaces between the partition walls and other refractory walls, if the spaces are wider than 2 mm.

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Access to the combustion chambers The easiest way to get access to repairing refractory walls is through the waste sluice. Follow the instructions below.

Air cylinder for feeding door

Waste sluice with feeding door inside

Ash door

♦ Remove the inclined steel plate with the two handles from the bottom of the waste sluice. ♦ Remove the protective screen for the air cylinder (not shown on the picture above). ♦ Place a lifting jack, pallet stacker or similar on the floor in front of the ash door. ♦ This is for supporting the feeding door when opened, and the support base must be positioned approx. 60 cm (2 feet) above base level for the incinerator. ♦ The total weight of the feeding door is up to 200 kg (440 lb) – please be careful ! ♦ One person will hold the feeding door closed (in vertical position), while another person disconnects the air cylinder piston from the feeding door.

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♦ Both people can now open the feeding door manually and lower it slowly to the support base. The feeding door should now be in a horizontal position. ♦ Use the support to lower the feeding door further. During the repair work, the feeding door should be resting on the floor for easy access in and out of the waste sluice. If needed, the feeding door can be dismounted in the left and right bearings, and it can then be removed temporarily. ♦ Older incinerator designs have two air cylinders for the feeding door, one on each side of the waste sluice. In this case, one of the air cylinder pistons can be disconnected at first. Then connect a pulley tackle in the hole in the feeding door arm, and the other end into a lifting eye on top of the incinerator. Tighten the pulley tackle with the feeding door in closed position. Disconnect the other air cylinder piston, and lower the door using the pulley tackle. ♦ After repair work of the refractory, the incinerator is reassembled.

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