Glossary
Gas Technology Glossary — SNG, LPG, Biomethane & Industrial Gas Terms
GasGenix — Key Definitions & Technical Reference
www.gasgenix.com | office@gasgenix.com
Introduction
This glossary provides definitions of key technical terms used in the field of gas technology, including gas mixing systems, synthetic natural gas (SNG) production, biomethane conditioning, LPG vaporization, and gas energy analytics. The definitions have been prepared in accordance with applicable European standards, including EN ISO 6976, EN 12405-1, and internal GasGenix technical specifications.
GasGenix applies these definitions across all stages of project delivery — from system concept and engineering design through to commissioning, service, and energy performance analysis.
1. Gas Types & Fuels
LPG — Liquefied Petroleum Gas
A mixture of liquefied hydrocarbon gases, primarily propane (C₃H₈) and butane (C₄H₁₀) — including isobutane and n-butane — in variable proportions, derived from petroleum refining.
Propane (Technical Grade)
A mixture containing approximately 95% (v/v) propane (C₃H₈) and approximately 5% (v/v) n-butane (n-C₄H₁₀), with possible trace quantities of other hydrocarbons, as specified in the supplier’s quality documentation.
bioLPG — Renewable Liquefied Petroleum Gas
A fuel chemically identical in composition and properties to conventional LPG, but produced from organic waste materials. bioLPG is a renewable alternative to fossil-derived LPG and can be used as a direct drop-in replacement in all LPG applications.
SNG — Synthetic Natural Gas
A propane-air or LPG-air mixture. Synthetic natural gas produced on-site as a mixture of propane (LPG) and air, prepared in a gas mixer to achieve combustion parameters — particularly the Wobbe Index (Wₛ) — as close as possible to those of the reference gas (e.g. natural gas or biomethane), ensuring combustion interchangeability and stable operation of end-use appliances.
bioSNG — Bio Synthetic Natural Gas
A biopropane-air or bioLPG-air mixture. Renewable synthetic natural gas produced on-site or at the customer’s facility as a mixture of biopropane (bioLPG) and air, prepared in a gas mixer to achieve combustion parameters — in particular the Wobbe Index (Wₛ) — as close as possible to those of the reference gas (e.g. natural gas or biomethane), thereby ensuring combustion interchangeability and stable operation of end-use appliances.
2. Combustion & Energy Parameters
Gross Calorific Value (GCV) / Heat of Combustion
The quantity of heat released by the complete combustion in oxygen of a specified quantity of gas at a constant pressure p₁, where all combustion products are returned to the same specified temperature t₁ as the reactants, and all products are in the gaseous state — except water, which is condensed to the liquid state at temperature t₁.
Note: When the quantity of gas is referred to one mole, the heat of combustion is denoted (Hᴄ)ᴳ(t₁,p₁); per unit mass it is denoted (Hᵀ)ᴳ(t₁,p₁); per unit volume it is denoted (Hᵛ)ᴳ(t₁,p₁; t₂,p₂), where t₂ and p₂ are the reference conditions for the gas volume.
Source: EN ISO 6976:2016-11
Superior Wobbe Index (Wₛ) / Upper Wobbe Number
The gross calorific value per unit volume under specified reference conditions, divided by the square root of the relative density under the same metering reference conditions.
Note: In common use, and without any other qualifier, the term 'Wobbe Index’ refers to the Superior Wobbe Index as defined here. The Wobbe Index is the primary parameter for ensuring gas interchangeability between different gas types and mixers.
Source: PN-EN ISO 6976:2016-11
3. Gas Mixing Systems & Components
Reference Gas (Base Gas)
In GasGenix systems: the gaseous fuel that forms the basis of the technological process supply, to which the selection and settings of the mixing system are referenced (e.g. for conditioning or stabilisation of parameters using a corrective gas or mixture). The parameters of the reference gas — in particular the Wobbe Index (Wₛ) — constitute the target or limit values for the substitute or supplementary mixture at the outlet of the mixing system, as delivered to end-use appliances.
Corrective Gas
In GasGenix systems: a gas stream or gas mixture dosed into the reference (base) gas within the mixing system, for the purpose of conditioning and stabilising the fuel parameters delivered to end-use appliances. Corrective gas is used in particular to regulate qualitative parameters of the mixture, such as gross calorific value (Hₛ), Wobbe Index (Wₛ), and — depending on the application — methane number. The corrective gas may serve an enriching function (e.g. propane / LPG / bioLPG) or a diluting / de-rating function (e.g. air in a propane-air mixture, or nitrogen).
Gas Mixer
A device or assembly of process equipment designed to combine two or more gas streams to produce a homogeneous mixture with the required qualitative and quantitative parameters. It provides controlled dosing of components, effective mixing (uniform concentration distribution across the flow cross-section), and stability of mixture parameters over time — including gross calorific value and Wobbe Index — while maintaining the required pressure and flow conditions and complying with process safety requirements, including operation in potentially explosive atmospheres (ATEX zones).
Static Mixer
A gas mixing component without moving parts, in which the mixing of two or more streams is achieved solely through the appropriately designed flow geometry. It typically consists of a pipe section or a mixing insert with baffles (mixing elements) that force repeated separation and re-combination of streams, increasing turbulence and dispersion. The objective is to achieve a uniform concentration distribution across the flow cross-section and to minimise fluctuations in mixture parameters at the outlet, while maintaining the required hydraulic conditions — including an acceptable pressure drop.
4. Measurement Conditions & Standards
Normal Conditions (Standard Reference Conditions)
Conventional reference conditions used in the gas industry for expressing gas volume and flow as Nm³, and energy quantities as MJ/Nm³. Defined as an absolute pressure of 101.325 kPa and a temperature of 273.15 K (0°C).
Combustion Reference Conditions
The specified temperature t₁ and pressure p₁ at which the fuel is assumed to be burned.
Note: In Poland, in accordance with applicable regulations, the reference conditions for combustion are 25°C / 101.325 kPa.
Source: EN ISO 6976:2016-11
Working (Operating) Conditions
The actual operating conditions of the medium within the installation at a given measurement point, defined by at least the pressure (usually absolute) and temperature of the gas, and where required also by composition and compressibility factor.
PTZ Conversion (Pressure-Temperature-Compressibility)
The conversion of gas volume as a function of pressure and temperature, taking into account the compressibility factor.
Source: EN 12405-1:2022, clause 1
5. GasGenix Core Services — Reference Terms
Backup Gas System
A standby gas supply installation designed to maintain continuity of gas delivery to end-use processes in the event of interruption to the primary gas supply. GasGenix backup systems are typically based on SNG (propane-air or LPG-air) mixing technology, ensuring Wobbe Index compatibility with the reference gas.
Biomethane Enrichment System
An installation for conditioning raw biomethane by injection of propane or LPG to increase its calorific value and Wobbe Index to levels compatible with natural gas grid requirements or end-use appliances. GasGenix enrichment systems include precision flow control, Wobbe Index monitoring, and ATEX-compliant components.
CO₂ Vaporization System
A system designed to convert liquid carbon dioxide (CO₂) into the gaseous phase for industrial process applications. GasGenix CO₂ vaporization systems use water bath vaporizers with integrated gas-fired boiler heating circuits, remote monitoring, and pressure safety systems to prevent dry ice formation below the CO₂ triple point (5.18 bar / −78.5°C).
OPEX (Operational Expenditure) Analysis
A comprehensive assessment of the ongoing operational costs associated with running a gas system — including fuel consumption, energy use, maintenance, and service — carried out by GasGenix to demonstrate the economic benefits of backup or mixing system implementation to the client.
Gas Energy Analytics
The systematic measurement, monitoring, and analysis of gas energy parameters — including flow rate, calorific value, Wobbe Index, and consumption — to optimise system performance, support regulatory compliance, and provide clients with accurate energy accounting data.
6. GasGenix System Types — Technical Descriptions
The following section provides professional technical descriptions of the principal gas system types engineered and delivered by GasGenix. Each system is defined by its functional objective, process principle, gas streams involved, key technical parameters, and typical industrial applications. All systems comply with applicable European standards (EN ATEX, PED).
6.1 Gas Backup System / SNG (LPG + Air) Blending System
Process Principle
NG = SNG (LPG + AIR) — Wobbe Index (MJ/Nm³)
An on-site synthetic natural gas (SNG) production and blending system designed to provide a fully interchangeable backup gas supply in the event of interruption or insufficient capacity of the primary natural gas (NG) network. SNG is produced by precisely blending liquefied petroleum gas (LPG — propane or bioLPG) with compressed atmospheric air in a controlled volumetric ratio, calibrated to achieve a Superior Wobbe Index (Wₛ) equivalent to that of the reference natural gas. The key engineering principle is: NG ≡ SNG (LPG + AIR) — the output SNG is combustion-interchangeable with natural gas without any modification or replacement of burners, heat treatment equipment, or end-use appliances.
Main System Equipment
LPG storage tank → LPG transfer pump → containerised LPG vaporization station → SNG blender (LPG + AIR mixing skid) → SNG buffer tanks (optional) → peak shaving system → process / factory supply
Air supply: industrial air compressor + receiver, inlet pressure 6–8 bar.
6.2 Methane Number Stabilization System (Syngas + CH₄)
Process Principle
Syngas + NG (or Biomethane) = Stable Methane Number (MN)
A gas blending system designed to continuously monitor and regulate the methane number (MN) of a process gas stream — typically a synthesis gas (syngas), pyrolysis gas, or other low-MN gaseous fuel — by controlled injection of natural gas or biomethane (high-CH₄ corrective stream) to raise and stabilise the MN to the level required by downstream gas engines or turbines.
What is Methane Number (MN)?
The methane number is analogous to the octane number in liquid fuels: it quantifies the knock resistance of a gaseous fuel mixture in internal combustion engines. Pure methane (CH₄) has MN = 100; hydrogen (H₂) has MN = 0. A low or unstable MN causes engine knock, increased mechanical wear, thermal overload of pistons and valves, derating of output power, and unplanned shutdowns — with significant OPEX and reliability consequences.
System Configuration
Pyrolysis gas reactor or syngas source → Methane Number Stabilization Mixer → buffer tank (optional) → cogeneration unit / factory / industrial process
NG pipeline supplies the corrective gas stream. The blending ratio is continuously adjusted by the control system based on real-time online gas quality measurement.
6.3 Heating Value Stabilization / Enrichment System (NG + LPG)
Process Principle
NG + LPG → Heating Value ↑ (MJ/Nm³)
A gas blending system designed to maintain or increase the gross calorific value (GCV / Hₛ) and Superior Wobbe Index (Wₛ) of a natural gas stream by controlled, continuous dosing of liquefied petroleum gas (LPG — propane or propane/butane mixture) as a high-calorific corrective gas. The enriched NG+LPG mixture at the outlet meets or exceeds the target gas quality parameters required by industrial end-use appliances and process equipment.
Main System Equipment
LPG storage tank → LPG transfer pump → containerised LPG vaporization station → heating value stabilization / enrichment mixer (NG + LPG dosing skid) → enriched gas stream to factory / process.
6.4 Energy Flow Control Gas Blending System (SNG + NG)
Process Principle
NG (limited) + SNG = defined energy output (kWh)
A gas mixing system engineered to achieve and maintain a precisely defined energy flow rate in the final blended gas stream — expressed in energy units (kWh/h or MJ/h) — rather than purely in volumetric or mass flow terms. The system continuously blends a supplementary SNG stream with a capacity-limited natural gas supply to ensure the process consistently receives the required energy input, regardless of NG network constraints.
Main System Equipment
LPG storage tank → pump → containerised LPG vaporization station → SNG blender → SNG buffer tanks → peak shaving system (SNG + NG blending) → factory / process supply
6.5 CO₂ Reduction (Decarbonization) Fuel Blending System
Biomethane + NG | BioSNG + NG | BioSNG + SNG
Process Principle
BioSNG + NG = CO₂ reduction | BioSNG + SNG = CO₂ reduction
A gas blending system designed to progressively reduce the carbon intensity of a fossil fuel gas stream by controlled injection of renewable gaseous fuels — specifically biomethane or bio-synthetic natural gas (BioSNG, produced from bioLPG/biopropane + air) — into the primary natural gas or SNG supply. The system delivers a measurable, verifiable reduction in CO₂ emissions proportional to the renewable fuel blending ratio, while maintaining full combustion interchangeability with existing burners and process equipment.
Two Principal System Configurations
Configuration A — Biomethane + SNG stream: Biomethane (from a biogas upgrading plant) is injected into the SNG (LPG+AIR) peak shaving stream. Equipment: biogas plant → biomethane injection → peak shaving system (SNG+Biomethane) → factory. This configuration reduces the fossil carbon fraction of the SNG backup supply.
Configuration B — BioPropane + AIR = BioSNG + NG stream: Renewable biopropane (bioLPG) is blended with air to produce BioSNG, which is then injected into the NG supply stream. Equipment: BioPropane tank + LPG tank (switchable) → pump → containerised vaporization station → SNG blender (BioLPG+AIR) → BioSNG buffer tanks → peak shaving system (BioSNG + NG) → factory. This configuration enables a fully renewable backup supply pathway without requiring a biomethane grid connection.
Regulatory Compliance & Reporting
The system provides continuous monitoring of the renewable fuel fraction, real-time CO₂ intensity calculation (kgCO₂/MJ and tCO₂eq), and full data logging for sustainability reporting under EU ETS, CBAM, ESG/CSRD-ESRS frameworks and national green gas certification schemes (e.g. GOs — Guarantees of Origin). Designed for capacity scaling as renewable fuel availability increases over time.
Source: GasGenix internal definition; EU RED III Directive 2023/2413; EU ETS Directive 2003/87/EC; KOBIZE emission factors (PL)
GasGenix Sp. z o.o. | office@gasgenix.com | www.gasgenix.com
This glossary is subject to periodic revision.