Today's KNOWLEDGE Share : Ethylene Production Based On Steam Cracking:

Today's KNOWLEDGE Share

Knowledge of Petrochemical units:

Ethylene Production Based On Steam Cracking:

Ethylene production is primarily achieved through steam cracking, where hydrocarbons like ethane, propane, or naphtha are heated to high temperatures (around 800-900°C) in the presence of steam. This process breaks down large hydrocarbon molecules into smaller ones, with ethylene being a major product. The cracked gases are then rapidly cooled to stop the reactions, and the mixture is sent through a series of separation and purification steps to isolate ethylene. Ethylene is a key building block in the petrochemical industry, used to produce various plastics, chemicals, and synthetic materials.

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Process Flow Diagram Overview:

Using the basic flow sheet in the appendix:

Feed Furnace: The hydrocarbon feedstock (e.g., ethane or naphtha) is preheated in the feed furnace to around 400°C.

Cracking Furnace: The preheated feed is further heated to about 800°C in the cracking furnace, where thermal cracking occurs. This high temperature breaks down the hydrocarbons into smaller molecules like ethylene, propylene, and other by-products.

Quenching: The cracked gas is rapidly cooled in a quenching system to stop further reactions. This is typically done using water or oil quenching.

Caustic Wash: The cooled gas undergoes a caustic wash to remove acidic impurities like hydrogen sulfide and carbon dioxide.

Drier: The gas is then dried to remove any remaining moisture.

Cold Box: The dried gas is cooled further in a cold box to condense and separate the lighter hydrocarbons.

Demethaniser: The gas enters the demethaniser, where methane is separated from the mixture.

De-ethaniser: The remaining gas is sent to the de-ethaniser, where ethylene and ethane are separated from heavier hydrocarbons.

Ethane Product Compressor: Ethane is compressed and recycled back to the cracking furnace.

Secondary Demethaniser: Further separation of methane from the gas mixture.

Ethane Depropaniser: Separation of propane from the ethane-ethylene mixture.

C2 to C4 Splitter: Separation of ethylene (C2) from other hydrocarbons like butanes (C4).

MAPD Converter: Conversion of methyl acetylene and propadiene (MAPD) impurities to ethylene and propylene.

Final Purification: The purified ethylene is then compressed and stored or sent for further processing.

source:Saeed rooeentan