The prerequisite factors for cracking thick walled seamless steel pipes are temperature and reaction delay time, as well as the types of hydrocarbon raw materials. The production and manufacturing of chemical plants adopt the form of catalytic cracking. In a cracking furnace (tubular furnace or heat storage furnace), petroleum hydrocarbons are converted into small molecule water cyclohexanols, alkynes, and aliphatic hydrocarbons, such as butadiene, PE, butadiene, acetylene gas, benzene, and xylene.
Provide a detailed introduction to the standard specifications for high-temperature thick walled seamless steel pipes used in cracking furnaces, as well as key points for furnace wall production, manufacturing, and inspection. Features: Also known as catalytic cracking or thermal cracking. The whole process of nitrogen compounds breaking into small amount of unsaturated hydrocarbon at high temperature (above 700 ℃). Under cracking conditions, heat-resistant thick walled seamless steel pipes are also reflected in condensation reactions, cyclization, and dehydrogenation. Due to the complexity of the manifestation formed, it is generally divided into two stages.
The target substances transformed from raw materials are butadiene and polyethylene, which are called primary reactions. In the second stage, the first embodiment of thick walled seamless steel pipes is converted into butadiene and polyethylene, which are then converted into alkynes, dienes, p-xylenes, and cycloalkanes, and converted into radon and coke. This manifestation is called secondary embodiment. Therefore, cracked substances are generally compounds of various components.
The thick wall seamless steel pipe of power station will produce organizational damage and stress relaxation damage when it operates for a long time under ultra-high pressure. With the increasing damage level of the pipe, the fracture toughness and tensile strength of the material will continue to decrease, which will greatly increase the probability of damage to thick wall seamless steel pipe, especially the steel of power generation units in extended service. The damage and ineffectiveness of 12Cr1MoV alloy pipes seriously endanger the safety and economic environment of power plants. Therefore, the appropriate diagnosis of the damage level of steam pipes and the effective evaluation of their remaining service life are the main measures to prevent the early invalidation of steel and proficiently grasp the remaining service life of power generation units that have exceeded their service life while ensuring the safe operation of steel.
