Biogas Burners and Dual/Triple Fuel Burners

Based on more than 30 years of practical experience with biogas use as fuel, GWE can offer burners and boiler modifications to utilise the produced biogas in single and multiple fuel arrangements. GWE has supplied and commissioned biogas utilisation systems in steam boilers, water heaters, thermal oil boilers and direct fired driers, and in combination with a very large variety of other fuels like bunker fuel oil, light fuel oil, natural gas, propane, LPG, coal, lignite, and biomasses like rice husk, bagasse and saw dust.

Biogas Burner for Steam Boiler at Khon Kaen Brewery, Thailand

GWE’s biogas burner modifications are unique as they are controlled in such a way that all produced biogas is used as fuel at all times, and this without the use of a gas holder (costly, dangerous and a permit nightmare).

Standard burner controls “look forward”, because they are designed for unlimited fuel supply at a constant pressure, like is the case for example with natural gas. But in a situation where biogas is (one of) the fuel(s) the pressure on the methane reactor(s) must be kept constant, meaning that the controls must be “looking backwards”.

The burner conversion package to be supplied must be able to burn successfully variable amounts of biogas with variable pressure, and moreover, in case it is a dual fuel burner, in variable ratios of biogas and fuel oil, while giving biogas priority so ALL the biogas is burnt and fuel oil is topped up as demanded by the steam consumption.

Dual Fuel Biogas Train at Echuca Rochester, Australia

Standard burner systems for dual fuel means normally that they burn 2 fuels but in a FIXED ratio. Oil and gas go up and down together in this fixed ratio according to the boiler command. The combustion air is then also increased or decreased in a preset fixed ratio. These ratios are not electronically controlled but maintained by simple mechanical links.

The result of this, if used when one of the fuels is biogas, which is produced in varying amounts and at varying pressures, is that there will be either too little gas, which will shut the system down, or too much gas, which will see some of the gas go to the flare. Furthermore there will be continuous pressure fluctuations on the methane reactor with this system, which will have a detrimental effect on its operation (it will cause bacterial sludge losses).

Another problem of standard burner system if used for biogas is that most accessories on the biogas side of the burner are in CARBON steel, in stead of stainless steel as it has to be with biogas. If this is so, then there are not only operational but also safety concerns (carbon steel will be corroded by the H2S and the pure water in the biogas and sooner or later the control valves etc.. will get stuck, which can create a hazardous situation). Some systems also have no flare arrestor, another safety hazard.

GWE’s biogas and multiple fuel burners are the proper answer to all those problems. They are fully instrumented and controlled for freely modulating dual fuel operation, burning all the produced biogas as priority, thereby maximising the reduction of the client’s fuel bill. And they have been designed to work fully automatically and trouble-free for many years.

Most systems pay themselves back in 1 – 2 years, sometimes even in less than 1 year.