ethylene Basic cracking furnace
objective :
Processing various raw materials such as natural gas, refinery gas, goods and naphtha into cracked gas, and then supplying it to other ethylene plants to finally produce triene benzene (ethylene, propylene, butadiene, benzene toluene 、 xylene ）And other products.
type :
1. Heat supply mode:
Direct heating: regenerative furnace cracking, sand furnace cracking, fluidized bed cracking;
Indirect heating: Tube furnace cracking;
2. Tubular cracking furnace:
(1) Process: double radiation chamber, single radiation chamber, millisecond furnace;
(2) Furnace type:
technology ：
1. Raw material preheating:
(1) Preheating of preheater: 70~80 ℃;
(2) Dilution steam preheating: 150 ℃;
(3) Preheating of convection section: 200~600 ℃;
2. Raw material cracking: 800~900 ℃;
3. Cracking gas cooling: 400~200 ℃
Furnace structure ：
Existing problems ：
1. Coking in tube: (coking will block the gate, affect the medium flow and heat transfer)
(1) Metal catalyzed coking: metal catalysis → dehydrogenation and coking → intercrystalline carburization → coke layer diffusion;
(2) Aromatic condensation and coking: aromatic condensation and dehydrogenation → tar droplets → dehydrogenation and coking;
(3) Free radical coking: dehydrogenation of unsaturated hydrocarbon → free radical → addition of free radical on the surface of coke layer → coke layer growth;
2. Corrosion problems:
Acid dew point corrosion of tube bundle in convection section: sulfide in fuel will produce SO after combustion two 、SO three Gas causes * * * dew point corrosion in the convection section;
2FeSO four SO two O two =Fe two (SO four ) three
3. Energy saving of furnace efficiency:
Coating application ：
(1) Anti coking inside furnace: ZS-822?
(2) High temperature anti-corrosion: ZS-722
(3) High temperature energy saving: ZS-1, ZS-1061, ZS-233
