1. Appearance inspection should be carried out on all welding joints of furnace tube welding, the shape and size of welding joints should meet the design requirements, and the welding joints and base metals should have smooth transition.
2. The depth of the edge bite of the furnace tube welding mouth shall not be greater than 0.5mm, and the two sides of the continuous length of the edge bite shall not exceed 10% of the total length of the welding mouth and shall not exceed 100mm. Otherwise, grinding or repair welding should be carried out to make it smooth and excessive.
3. There should be no defects such as cracks, blowholes, arc pits and visible slag inclusion in the welding mouth of furnace tube and heat affected zone.
4. Furnace wall lining is an important part of tubular heating furnace, it mainly includes brick structure of brick laying, hanging brick, brick pulling, refractory concrete, wear-resisting concrete, pouring material, heat-resistant concrete structure of plastic, aluminum silicon fiber pasting, fire-resistant fiber structure of aluminum silicon fiber spraying, brick and fire-resistant five forms, including fiber mixed structure and heat-resistant concrete and fire-resistant fiber mixed structure.
5. If ultrasonic detection is adopted in the welding line of furnace tube, re-inspection should be conducted by ray detection, and the re-inspection ratio should be 20% of the total welding line.
6. After the fire-resistant casting furnace lining is baked, the crack width of the furnace lining surface should not be more than 3mm, and the continuous length should not be more than 500mm.
7. The form and size of the furnace tube welding groove should be processed by mechanical method according to the design pattern. During the high-speed cutting, the cooling agent should be applied to prevent the surface layer from hardening. Under special circumstances, the plasma gas cutting is allowed for some welding joints, after cutting, the groove must be polished and about 3mm oxidation hardening layer must be polished.
8. The welding group of furnace tube, furnace tube and elbow should be conducted on the tire tool correspondingly, and the butt clearance is 2.5 ~ 3mm, the amount of single side misalignment of inner mouth: when the external diameter is less than 102mm, the amount of misalignment is less than or equal to 0.5mm, when the external diameter is more than 102mm, the amount of misalignment is less than or equal to 1mm.
9, furnace tube positioning welding used electrode and welding technology and formal welding same. 4 points of spot welding evenly at each welding mouth, and each point is 20 ~ 30mm and should be thickness, spot welding at shall not have cracks and other defects.
10. When preheating before welding and heat treatment after welding are needed, electric heating should be adopted, and flame heating is generally not allowed. The heat treatment process must be controlled and recorded according to the heat treatment curve.
11, tube and quick-return elbow arrival inspection should be quality prove full data, chemical composition, mechanical properties, outside diameter and wall thickness etc. shape deviation meet the design requirements.
12. Under normal operation, the exhaust temperature of the heating furnace should be close to the design value. If the exhaust temperature is high, the heating furnace will have low thermal efficiency and high fuel consumption.
13, unshaped refractory fiber lining of the dimensions allows deviation: thickness deviation:-5 ~ 10mm; verticality: less than 5mm per meter and full height less than 15mm; surface flatness: use a 2-meter ruler to check that the gap between the ruler and the furnace lining is less than 8mm.
14, general casting, plastic refractory and spraying fiber lining radiation mao gu ding spacing is 300 x 300, nail top from lining inner surface 40mm; convection mao gu ding spacing is 250 x 250, nail top from lining inner surface 35 ~ 40mm; top and chimney mao gu ding spacing is 200 x 200, nail top from lining inner surface 25 ~ 30mm.
15, mao gu ding before welding should be cleared furnace wall board rust oil pollution; welding rod should be according to mao gu ding material selection; should be full circumference full Weld and weld full no bite meat defects.
16, castable construction must by material requirements for safe keeping, ratio, and mixing, pouring and conservation. According to ratio join aggregate, powder and binder dry-mixed uniform then add water apply mandatory mixer stir fully.
17, castable should be continuous construction, with varieties castable lining no layering construction, section construction of Construction Joint Interface reserved width should be greater than 200mm and should be made step sewing, if for double-layer lining, two-layer seams should be staggered more than 100mm, interface should be lining while conserving.
18, unshaped refractory material lining of the construction and inspection should be in strict accordance with the request of design files, the petrochemical furnace construction and acceptance of SH3534 and the petroleum chemical tube furnace lightweight castable lining works technical conditions implement the provisions of SH/T3115.
19, production device management staff should Daily at least this device jurisdiction heating furnace operation of a patrol. The weekly should do a furnace efficiency analysis work; monthly prepared heating furnace operation situation analysis.
20, front hot oil (soda)-preheater for utilization device low temperature waste heat to heating furnace for air, not only energy saving, more important is to improve into Last stage flue gas preheater air temperature, and wall temperature increase, can effectively reduce flue gas preheater of low temperature dew point corrosion.
21, mao gu ding mounting spacing should comply with the design requirements or of the lining material requirements.
22, furnace tube welding should be 100% nondestructive flaw. Detection method should be for ray detection.
23, once mixing amount should be initial setting front pouring, lost construction workability material shall not be used.
24, according to the degree of damage repair or replacement convection chamber, radiation chamber and flue the parts of furnace wall and lining.
25, according to the degree of damage repair or replacement, Burner, soot blower, air preheater, induced draft fan, blower and flue baffle etc.
26. The maintenance of the heating furnace includes repairing the steel structure of the furnace body, repairing the attached pipelines such as smoke, air duct, fuel oil, fuel gas and steam, and painting, corrosion prevention and heat preservation.
27, heating furnace servicing front must partitions and furnace connected process pipeline with blind, full purge and Keep furnace air smooth, in laboratory qualified, comply with the relevant safety provisions of the rear can into furnace inspection, maintenance.
28, servicing should be checked before furnace tube bent deformation, bulge, oxidation bao pi, crack, corrosion, erosion, etc.
29, should be combined with servicing arrangements furnace tube thickness determination, and according to the actual corrosion, appropriate extension thickness measurement cycle.
30, servicing should be checked before tube sheet, diao gua jian and guide rod deformation, fracture and stuck etc. damage.
31, overhaul front inspection refractory brick rack, bao wen ding and various riveting parts oxidation, deformation and damage condition.
32, overhaul front check elbow box insulation shall be in good condition elbow door should no damage deformation and reliable seal.
33, overhaul front inspection induced draft fan, blower bearing is intact, impeller and enclosures whether corrosion, base is loose.
34, overhaul front check air preheater heat exchange tube corrosion, damage and dust scaling.
35, overhaul front inspection soot blower transmission part damage, soot blowing tube and ejector nozzle corrosion, program-controlled part is working properly.
36, servicing front inspection flue, air duct baffle and manual or electric adjustment mechanism whether corrosion, card astringent or action doesn't work well.
37, lying down put furnace tube two adjacent bracket the bending degree greater than furnace tube outside 2 times the furnace tube should be replaced.
38, microstructure, with grain boundary oxidation, serious ball of, decarburization and grain boundary flaws such as crack furnace tube should be replaced.
39, tube-ray inspection qualification level for grade Ⅱ, ultrasonic detection qualification level Ⅰ level.
40, bulge, serious cracks or reticulate crack furnace tube should be replaced.
