Natural Gas substitution | help for disturbances in NG supply | gas mixture propane/air

721 199 Alexander Hanf

LT GASETECHNIK is your partner on the topic of “natural gas substitution with propane-air gas mixture” due to shutdown or embargo in the Russia/Ukraine conflict.

LT GASETECHNIK supplies an important component of the entire system, the gas mixing system:

Design sheme LT Gas Mixing System for propane air:

  • Installation in an insulated container or in a field cabinet with mechanical and electrical parts
  • Per gas line (often two for redundancy reasons):
    1. Ball valves/flaps
    2. Filter
    3. Inlet pressure transmitter
    4. Pressure regulator with safety shut off valve, pressure stage as agreed
    5. Temperature and pressure compensated flow measurement
    6. Flow control or pressure control as needed
    7. Non-return valve
  • gas mixture
  • outlet pressure transmitter
  • Gas analysis with SIL 2 oxygen gas analyzer and safe shutdown independent of the control with limit indicators and fittings.
  • Wobbe-Index analyzer
  • Output flange nominal diameter according to pressure and performance, pressure rating according to agreement
  • Gas warning system
  • Control based on flow, calorific value of natural gas or Wobbe index
  • Fully assembled and tested, ex works, with CE marking, 3D drawings and full documentation in German

Possible options for the gas mixing system (incl. gas analyzer and control system)

  • Redundancy:
    • Redundant gas mixing sections with automated valves and automatic time slice-controlled switching
    • Redundant control system
    • Redundante SIL 2 gas analyzer and switch-off
  • Control:
    • Connection to higher-level controls via interfaces such as: B. Profibus, Profi-Net etc.
    • UPS
    • Remote-Support by VPN
  • Gas analyzis:
    • Analysis device(s) for continuous online measurement and display of the calorific value, the Wobbe index, the standard density and the minimum air requirement
    • Gas chromatograph
    • Bottle holder, bottle removal station for calibration gas(es)
  • Documentation:
    • Software source code
    • Documentation in other / further languages
  • Delivery, commissioning, spare parts package, maintenance, maintenance contract

The entire system for natural gas substitution with a propane-air gas mixture:


  • Truck unloading station with filling and shuttle connection
  • (Earth-covered) buffer vessels (one or more)
  • Hot water or electrically heated evaporator system, (mounted in a gas mixer container or separate container) with pressure control station
  • Gas/air mixing system, with adapted performance for the production of analogue to existing natural gas

Official requirements

  • Depending on your local requirements Details in your local regulations <In germany: for a 29 t vessel (larger than 9 t and smaler than 30 t) a simplified procedure is required WITHOUT a public display. In Germany there are local laws and regulations (of the federal government). Local regulations apply …
    In principle in Germany TRBS 3146 “Fixed pressure systems for gases” applies to setting up, setting up and filling. According to § 3 BetrSichV and § 6 GefStoffV, all hazards that can arise when setting up, setting up, filling, storing, emptying, maintaining, shutting down and dismantling stationary pressure systems for gases must be determined. For risk assessment when working with gases, see TRGS 407
  • For a 165 t vessel consult local authorities In principle, TRBS 3146 3146 “Fixed pressure systems for gases” apply.
    • The approval period depends on local conditions. Formally, the authority has a deadline of seven months for the approval of a new system with public participation after a declaration of completeness; realistically, at least 12 months should be set here.
    • For approvals for modifications to existing systems, the theoretical value is four to six months, realistically at least 12 months.

Please note the Major Accident Ordinance

In any case, it must be checked whether the additional use of propane/liquefied gas will exceed quantity thresholds within the meaning of the Major Accidents Ordinance. This could result in additional documentation and testing obligations. The storage of propane from 50 t already falls under the Major Accident Ordinance, i.e. systems that were not previously classified as incident facilities will then fall under the requirements of the Major Accident Ordinance for the first time, regardless of which other incident-relevant substances are being handled.


  • Depending on redundancies (evaporator/gas mixing lines)
  • Outlet pressure(s)
  • Gas mixture analysis (SIL, Wobbe etc.)
  • Delivery time: Please inquire

Contact us for further information: