定义Definition
烃是只由碳和氢两种元素组成的化合物，是石油和天然气的主要成分。按结构可分为脂肪烃（烷烃、烯烃、炔烃）、脂环烃和芳香烃（如苯）。烃是重要的燃料，也是有机化工的基本原料。
A hydrocarbon is a compound of carbon and hydrogen only, the main constituents of petroleum and natural gas. By structure they are aliphatic (alkanes, alkenes, alkynes), alicyclic, or aromatic like benzene. Hydrocarbons are important fuels and the basic feedstock of the organic chemical industry.
来源与分离Sources and separation
原油通过分馏按沸点分成若干馏分：炼厂气、汽油、石脑油、煤油、柴油、重油和沥青。长链烃经裂化生成短链烷烃和烯烃，满足对汽油和乙烯的需求。
Crude oil is separated by fractional distillation into fractions by boiling point: refinery gas, petrol, naphtha, kerosene, diesel, fuel oil and bitumen. Cracking breaks long-chain hydrocarbons into shorter alkanes and alkenes to meet demand for petrol and ethene.
燃烧与环境Combustion and the environment
烃完全燃烧生成 CO₂ 和 H₂O；不完全燃烧生成 CO 和碳黑。燃烧化石燃料排放的 CO₂ 是主要的温室气体，杂质硫燃烧生成的 SO₂ 会形成酸雨。
Complete combustion gives CO₂ and H₂O; incomplete combustion gives CO and soot. CO₂ from burning fossil fuels is the main greenhouse gas, and SO₂ from sulfur impurities causes acid rain.