Propylen

System Composition

Highly similar to an ethylene plant, mainly including: Raw material pre-treatment (desulfurization, dearsenization, drying) Cracking / reaction system Quench and fractionation system Cracked gas compression and purification system (acid gas removal, dehydration, alkyne removal) Cryogenic separation system Propylene distillation and refining system

Technologies

Ethane Cracking：Highest ethylene yield and lowest cost, with propylene as a by-product. Hydrogenated Tail Oil Cracking：Cracking of heavy feedstocks enables co-production of ethylene, propylene and aromatics, delivering high overall economic efficiency. Advanced Technologies：Linde, Linde-TECHNIP, Shaw, Stone & Webster (SW), Lummus, KBR and SINOPEC cracking technologies.

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产品介绍

Propylene (C₃H₆) is a key unsaturated hydrocarbon and one of the most important basic feedstocks in the modern petrochemical industry. It is a colorless, flammable gas at room temperature with a slight hydrocarbon odor. Its chemical structure contains a carbon‑carbon double bond, giving it high reactivity and enabling it to participate in polymerization, oxidation, halogenation, alkylation and other reactions, making it an essential building block for countless chemical products.

Propylene is mainly produced as a by‑product of petroleum refining processes such as fluid catalytic cracking (FCC) and ethylene steam cracking. With growing demand, on‑purpose production technologies like propane dehydrogenation (PDH) have become increasingly important to ensure stable supply. Its output and consumption are widely viewed as important indicators of a country’s petrochemical and manufacturing development.

As a core raw material, propylene supports a huge downstream industry chain. Its most important derivative is polypropylene (PP), a versatile thermoplastic used in packaging films, fibers, injection molding parts, automotive components, household appliances and medical supplies. Propylene is also used to produce acrylonitrile, propylene oxide, isopropanol, cumene, acrylic acid and other chemical intermediates. These products are widely applied in packaging, construction, automotive, textile, electronics, healthcare and daily consumer goods.

Compared with other basic chemicals, propylene has outstanding advantages in versatility, cost‑effectiveness and performance balance. Polypropylene made from propylene features light weight, high strength, heat resistance, chemical stability and good processability, which helps reduce material consumption and improve product durability.

Safety and environmental protection are essential in propylene production, storage and transportation. Propylene is flammable and explosive, so strict safety standards, leak detection systems and explosion‑proof facilities are required. In recent years, the propylene industry has been developing toward large‑scale devices, higher energy efficiency, lower emissions and greener production. Advanced technologies and circular economy practices are helping the industry achieve sustainable growth while meeting global market demand.

Types and Characteristics of Equipment

Type

Main Product Types of Propylene

Polypropylene (PP) Propylene oxide Acrylonitrile Isopropanol Acrylic acid & acrylates Cumene & phenol

Features

Molecular formula: C₃H₆. It is a colorless, flammable gas at room temperature with a slight hydrocarbon odor. As the second most important basic raw material in the petrochemical industry, it serves as a core feedstock for plastics, chemical fibers and rubber.

Propylen

Propylene is a colorless, flammable gas and important petrochemical feedstock.

Basic Principles and System Composition

Basic Working Principle

Hydrocarbon Steam Cracking (Main Production)：Propylene is co-produced with ethylene during high-temperature cracking of ethane, naphtha and hydrogenated tail oil. Catalytic Cracking / Propane Dehydrogenation (PDH)：Propylene is obtained as a by-product from catalytic cracking;high-purity propylene can be produced exclusively via propane dehydrogenation.

Overall System Composition

Core Reactions: Propane → Propylene + HydrogenHigh-temperature cracking of long-chain hydrocarbons → Ethylene + Propylene + Light components + Aromatics

Basic Principles and System Composition

Raw Material Pre-treatmentEthane / Naphtha / Tail Oil → desulfurization, dearsenization, drying → qualified feed High-Temperature CrackingFeed + dilution steam → cracking in furnace at 800–900°C → high-temperature cracked gas Quenching & Heat RecoveryRapid cooling to terminate reactions, recover heat to produce high-pressure steam Pre-fractionationSeparation of heavy components such as cracked heavy oil, gasoline and water Compression & PurificationMulti-stage compression → acid removal by amine/caustic scrubbing → drying → selective hydrogenation for alkyne removal Cryogenic SeparationLow-temperature separation of methane and hydrogen → fractionation of C2 and C3 fractions Propylene RefiningPurification in propylene distillation tower → polymerization-grade propylene product Storage & TransportationPressurized spherical tanks / low-temperature storage tanks → delivered to downstream units via pipeline, tanker or ocean vessel