Contents
What is LPG–air blending?
LPG–air blending is the controlled mixing of vaporised LPG with air to reduce the heating value per unit volume of the resulting gas. The equipment used for this process is called an LPG Air Blender.Adding air changes both the blend’s volumetric heating value and its density relative to air. The objective is to bring the gas properties within the range required by the intended application.Why is LPG blended with air?
LPG and natural gas have different heating values and combustion characteristics. LPG therefore cannot simply be supplied under the same conditions to a combustion system designed for natural gas. Controlled blending with air can help produce an alternative fuel with properties compatible with the existing equipment.One of the main applications is a natural gas backup system for industrial facilities. LPG storage, vaporisation and blending units can be designed together to provide the alternative gas supply required by the plant.A backup system can be considered for natural gas interruptions, supply restrictions or planned maintenance. Changes in the relative costs of natural gas and LPG may also make alternative fuel use worth evaluating. Economic suitability should be assessed using delivered fuel costs, usable energy and total operating costs.Performance depends on plant conditions
LPG–air blending alone does not guarantee higher efficiency, lower emissions or cost savings. Results depend on fuel properties, equipment compatibility, combustion settings and operating conditions.How does an LPG Air Blender work?
In a typical system, stored liquid LPG is first vaporised. The vaporised LPG and air are then combined in the Blender at the designed proportions. The prepared gas is supplied to the plant’s fuel line under the required pressure and control conditions.Main process steps
The Wobbe Index is one of the main parameters used to assess the blend. However, matching the Wobbe Index of natural gas does not, by itself, mean that the blend can be used in all equipment without adjustments. Gas composition, supply pressure and combustion equipment specifications must also be assessed.Learn about fuel interchangeability and the Wobbe Index →Storage
LPG is stored according to the plant’s fuel demand and required backup duration.
Vaporisation
Liquid LPG is vaporised to provide the required gas flow.
Blending
Vaporised LPG and air are combined in controlled proportions.
Supply and control
Blend pressure and gas properties are controlled to meet the plant’s operating requirements.
What should be assessed when designing a natural gas backup system?
The Blender should be selected together with the other components of the backup system. Capacity, gas quality, equipment compatibility and fuel changeover conditions must be considered as part of the overall design.System selection criteria
- Normal and peak gas demand
- Required backup duration and LPG storage capacity
- LPG composition and vaporisation capacity
- Air supply flow, pressure and quality
- Target gas properties and Wobbe Index
- Accepted fuel specifications for burners and other gas-consuming equipment
- Pressure control, automation and fuel changeover sequence
- Site layout, safety and maintenance requirements
Uestco LPG Air Blender systems
The suitability of a Uestco LPG Air Blender system for your plant can be assessed by reviewing your consumption profile, process conditions and natural gas backup requirements.
Plan your natural gas backup system with an LPG Air Blender
We can assess LPG storage, vaporisation and blending requirements based on your consumption profile and process conditions.
