A Step-by-Step Guide to LPG Production

Introduction

LPG is mainly a mix of propane (C3H8) and butane (C4H10). It comes from two main sources: natural gas processing and crude oil refining. Because it burns cleanly and is easy to move, LPG is vital in areas without electricity grids, in vehicle fuel, and as a raw material in chemical plants.

Knowing how LPG is made matters because-

•             It helps provide energy to the 3 billion people worldwide without grid access.

•             It gives off less CO2 than coal or diesel when heating.

•             It can grow with renewable versions like bioLPG.

Overview of the Production Process

LPG comes out of separating and refining fuels using steps like cooling, squeezing, and cleaning. The main stages are-

1.           Gas separation – At gas plants, heavier gases (C3–C5) are taken out using cold distillation or absorption.

2.           Refinery recovery – At oil refineries, LPG is taken out during distillation and cracking processes.

3.           Dehydration and sweetening – Water, H2S, and CO2 are removed to make it clean for use.

4.           Storage and bottling — LPG is turned into a liquid at around 8 bar pressure and stored in cylinders, tanks, or specialized ships.

About 40% of LPG comes from refineries, and 60% from gas processing.

Raw Materials and Input Requirements

Primary Feedstocks-

•             Natural gas (with 3–12% propane/butane)

•             Crude oil (processed in distillation and cracking units)

Additives and Utilities-

•             Amine solutions: remove sulfur gases

•             Drying agents: glycol or molecular sieves

•             Refrigerant units: chillers or expanders for cooling during separation

Purity Standards-

•             Must be over 90% propane/butane, under 0.005% sulfur (ISO 9162)

•             Less than 50 ppm water to prevent rust or solidifying

Emerging Inputs-

•             Biogas, bio-oil, and pyrolysis liquids are starting to be used as renewable LPG sources, especially in the EU and Japan

Major Production Routes

Regional Preferences-

•             The Middle East and the USA lead in gas-based LPG from shale and associated gas.

•             India, Japan, and the EU rely on imports and refinery production.

•             Scandinavia: testing bioLPG made from plants and tall oil

Natural gas processing

Refinery production

Equipment and Technology Used

Separation and Compression Units-

•             Turbo-expanders and JT valves for cryogenic NGL separation.

•             Absorber-strippers with lean oil or glycol for heavier hydrocarbon extraction.

•             Amine contactors (DEA/MDEA) for H2S and CO2 removal.

Storage and Distribution-

•             Spherical or bullet tanks are designed for 17–20 bar pressure at ambient temperatures.

•             Filling carousels for high-speed bottling; integrated leak and weight checks.

•             Vaporizers in industrial setups to re-gasify LPG for downstream use.

Automation and Control-

•             SCADA systems for cylinder traceability, leak detection, and level monitoring.

•             IoT-enabled smart meters in domestic LPG connections (India’s Ujjwala 2.0 initiative) to curb pilferage and ensure refill tracking.

Environmental and Safety Considerations

Emissions-

•             LPG burns cleaner than diesel or coal, emitting ~81% less CO2 per kWh than coal.

•             Leakage during transfer and venting poses risks; modern plants use vapor recovery units (VRU) to capture fugitive emissions.

Waste Streams-

•             Spent amine and glycol require treatment before disposal.

•             LPG cylinders that fail hydro-tests must be scrapped or recycled under metallurgical supervision.

Safety-

•             LPG is highly flammable (GHS Flammable Gas Category 1); storage facilities require fireproofing, emergency vent stacks, and gas detectors.

•             Colorless and odorless by default, ethyl mercaptan is added for leak detection.

Regulations-

•             Under OSHA 29 CFR 1910.110 and NFPA 58, strict rules govern storage, transport, and cylinder handling.

•             In the EU, EN 589 governs LPG quality for automotive use, while REACH regulations cover substance registration and safety data.

Conclusion and Future Innovations

LPG continues to evolve, moving from fossil-heavy to bio-sourced and circular-economy models. Advanced technologies like membrane separation, hybrid refrigeration systems, and renewable-solar liquefaction are being explored to make LPG greener. For instance:

•             Neste and SHV Energy are scaling BioLPG plants in Europe, targeting >40,000 tonnes/year by 2026.

•             Plastic-to-LPG pyrolysis units in South Korea and the Netherlands now recover 60–70% of waste plastic as LPG-range hydrocarbons.

•             Hydrogen blending into LPG pipelines is under test to create hybrid fuels for heating and transport.

As the world moves toward net-zero, multi-feedstock LPG hubs capable of processing gas, oil, bio-feedstock, and plastic waste will shape the next era of clean, flexible, and affordable energy.