Requirements for the Installation of Insulating Layer and Inner Lining Layer of Self-supporting Chimney
Requirements for the installation of insulating layer and inner lining layer of self-supporting chimney
Requirements for setting of thermal insulation layer
(1) When the flue gas temperature is higher than the specified high heating temperature of the steel cylinder wall, the thermal insulation layer shall be set.
(2) When the flue gas temperature is lower than 150 ℃ and the flue gas may cause corrosion to the chimney, the thermal insulation layer shall be set.
(3) The thickness of insulation layer is determined by temperature calculation, but the small thickness should not be less than 50mm. For the chimney of full radiation furnace type, the thickness of thermal insulation layer should not be less than 75mm.
(4) The thermal insulation layer shall be firmly connected with the chimney wall. When block material or amorphous on-site casting material is used, it can be fixed with anchor nails or metal mesh. Steel plate ring can be set at the top of the chimney to protect the edge of the thermal insulation layer. The thickness of steel plate ring shall not be less than 6mm.
(5) In order to support the weight of the thermal insulation layer, an angle steel reinforcement ring can be set every 1-1.5m on the inner surface of the steel chimney along the height direction of the chimney.
(6) When the chimney temperature is higher than 560 ℃, the anchor of the insulation layer can be made of stainless steel (1Cr18Ni9Ti); When the flue gas temperature is lower than 560 ℃, it can be made of ordinary carbon steel.
(7) For the chimney without thermal insulation layer, the outer thermal insulation measures or protective railings shall be taken for the chimney within the height range of 2m at its bottom to prevent scalding accidents.
Lining setting requirements
(1) The lining is set for one or more of the following reasons.
1) Heat insulation to avoid excessive temperature of cylinder wall;
2) Heat preservation, avoid condensation due to low flue gas temperature, and reduce cylinder wall corrosion.
(2) Lining material. The lining material shall be determined comprehensively according to the flue gas temperature and the corrosion property of flue gas
1) Refractory brick, high service temperature up to 1400 ℃, heavy dead weight and heavy construction
2) Diatomite brick, with high service temperature up to 80O ℃, light weight, good thermal insulation, and low expansion coefficient;
3) The acid-resistant brick is used for highly corrosive flue gas, and the service temperature is not * * 150 ℃. It cannot be used for the chimney with frequent flue gas temperature fluctuations;
4) Ordinary clay brick, high service temperature of 500 ℃, self-weight, good acid resistance;
5) Heat-resistant concrete can be configured with different heat-resistant concrete (200-1200 ℃) according to the flue gas temperature requirements, which can be cast in situ or prefabricated;
6) Diatom concrete, which is made of broken bricks as aggregate and alumina cement, can be cast in situ or prefabricated, and the allowable heating temperature is 150-900 ℃. It is a good thermal insulation material;
7) The FC-S coating of chimney is applicable to steel chimney with temperature less than or equal to 400 ℃. Main ingredients: binder -- special cement; Aggregates - aggregates with high silica fired paraffin as the main component; Admixture - acid-resistant fine powder. Construction method: now the inner wall of the cylinder is welded with short reinforcement and hung with steel wire, and then sprayed with 60-80mm thick FC-S spray paint;
8) High-strength lightweight castable, with a gravity density of 8-10kN/m3, and a heat-resistant temperature of 700 ℃, is reinforced with densely distributed anchors and the cylinder wall. The anchors are made of Y-shaped or V-shaped stainless steel plates. The cast-in-place thickness can be about 250mm;
9) Unshaped fire-resistant spray coatings FN130 and FN140 play the role of heat insulation, wear resistance and corrosion protection. The spray thickness can be 70-120mm, and the service temperature is 1200 ℃. In order to consolidate and spray paint, Y-shaped or V-shaped anchors shall be spot welded on the inner side of the cylinder wall with a spacing of 250mm.
(3) Lining support ring. The lining shall be the edge of the support ring, which shall not be less than 12mm, nor greater than? Of the lining thickness?. The cylinder head should be closed with stainless steel plate.