MULTI JET fuels

Heating oil made from crude oil is classified as one of two types: extra-light heating oil (fuel oil EL) and heavy fuel oil (fuel oil S). The quality requirements for heating oil are defined in DIN 51603. Light heating oil can be burned in furnaces, central heating systems and industrial firing plants without preheating. Heavy heating oil, on the other hand, has to be preheated for transport and combustion. The systems run with these fossil fuels, however, are increasingly subject to regulations and restrictions.

The BENNINGHOVEN gas burners can use liquid gas as a fuel when it is in the liquid phase, without first having to transform it into a gaseous state. This means that no extra peripheral equipment like an evaporator is needed, also avoiding the need for additional energy input.

Liquid gas burners and natural gas burners have the same mechanical structure. They differ only in the peripheral equipment, i.e. how the fuel is introduced into the burners.

Liquid gas, referred to as “associated gas,” is generated during the extraction of crude oil or natural gas. This associated gas used to be simply released into the atmosphere or burned in many cases. Today, more and more regions worldwide have banned burning, which has an additional positive impact on the increasing availability of liquid gas.

Wood is a renewable resource which can be produced sustainably and is therefore carbon-neutral when used as a fuel. With the MULTI-JET wood dust burner, BENNINGHOVEN has made it possible to burn wood dust in asphalt mixing plants – adding another product to the portfolio of burner technologies developed in-house. For plant owners, wood dust burners are a sustainable option for setting their plant up for the future.

The development engineers at BENNINGHOVEN have identified the ideal particle size for wood dust, which is produced mainly from scrap wood and wood waste. Identifying the optimum grading curve for the fuel is important for the flame geometry of the burner – and therefore for the effectiveness of heating the virgin mineral or the recycled asphalt (RAP). Several Benninghoven customers are already successfully using the MULTI JET wood dust burner.

The complete peripheral equipment includes the burner and dosing unit. The inlet to the dosing unit is the interface to the customer systems. The wood mill and the wood silo are provided by the customer.

Burner
The wood dust is fed into the burner with precision dosing by means of the feed fan and the dosing unit. In the burner head, a separate pilot flame then ignites the material. The control range for wood dust with pilot flame is 1:6; the calorific value of wood dust is approx. 18 MJ/kg depending on the type of wood.

The secondary fuel is used for the pilot flame, e.g. heating oil EL, liquid gas or natural gas.

The owner is obligated to ensure that the overall plant (for example the silo with the dosing system) is checked as part of a regular inspection as per the German industrial safety regulations (BetrSichV). Outside of Germany, the systems are subject to mandatory testing – the applicable national laws and directives must be observed.

Explosion protection (ATEX) especially for coal dust and wood dust

The principle of producing BtL fuels is based on liquefying biomass.

In the case of wood as a starting material, thermo-chemical conversion processes in a reactor use high temperature and high pressure to turn the cellulose-rich wood into pyrolysis oil.

The further processing steps include cleaning, synthesis and refining of the pyrolysis oils to produce BtL fuels

For wood or wood waste as a starting product, the challenge lies in the processing of the natural material that can vary greatly in its chemical composition. These fluctuations affect the final BtL product. Smaller fluctuations can be compensated for by adapting the preheating temperature. In the case of greater fluctuations or fuel changes, the settings have to be changed on site.

For new fuels, customers send their heating medium to Wittlich in a stainless steel container so that the correct basic burner parameters can be determined at the BENNINGHOVEN factory. There, the fuel is tested extensively and the optimum burner settings are identified.

• BENNINGHOVEN MULTI JET burner – installed on the dryer drum
• Coal dust is fed into the burner with precision dosing using the supply fan and coal dust dosing system
• In the burner head, a separate pilot flame then ignites the material
• This is switched off at a burner output of 20% of the nominal burner output
• The solid material flame continues to burn independently from this point or is automatically activated again when output drops below this value
• The auxiliary flame fuel can also act as an independent fuel
• Control range 1:5 coal dust only and 1:8 coal dust with pilot flame
• Calorific value of coal dust 20,900 kJ/m³
• Burner control, output control, coupled control, and switchover between the fuels are effected with a type-approved control

Asphalt production, recycling systems, combustion technology, control systems, and bitumen technologies – thanks to BENNINGHOVEN’s technologies, each of our customers can find the right solution for their specific site that fully complies with requirements and conditions.