Spark ignited engines can run on a variety of gaseous fuels. The majority of spark ignited generators over 10kW are designed to operate on natural gas. In well head or process gas applications, the natural gas supply can vary in methane content quiet substantially, with the methane percentages ranging from 40% to over 98% by mass.
Due to the variability in these well head gas applications, it is important that your spark ignited generator set has the ability to adjust the ignition timing. Most industrial generator sets will have the ability to adjust the timing, however the majority of systems on the market today require an operator to manually adjust a timing potentiometer on the electronic ignition module in order to either advance or retard the timing.
In a dual fuel applications the electronic ignition module has the ability to have two ( or more) fuel maps loaded into the software such that selecting between the two fuel maps can be achieved by grounding out a pin in the wiring harness. When the second fuel map is selected, the ignition module will automatically advance or retard the timing of the spark, thus changing the type of fuel that will optimally burn during operation.
One of the primary reasons to add a propane dual fuel system to your natural gas spark ignited gen set is that you can add the reliability of a closed source fuel to your well head, process, or pipeline gas supply. If for whatever reason your fuel source becomes unusable, either from a poor gas stream, limited process gas or disaster to your pipeline supply, the generator will automatically change over to your propane back up system. The dual fuel systems can be installed manually such that there is an operator interaction required, or they can be set up automatically such that any loss in natural gas fuel pressure will create a situation where the propane system engages and transfers the fuel supply to the engine from the natural gas supply to the propane system. When the natural gas supply returns to a suitable level, the propane system can automatically disengage and continue operating on the well head or natural gas supply.
If an automatic system is selected, a remote telemetry system can be added as well to notify a remote operator that the system has switched over to propane. The operator can then monitor the system to ensure that the unit is operating appropriately and determine when the machine changes back to its natural gas supply. Such a system is possible when using a fully digital control panel as pictured below.
Another great reason for using a dual fuel system is on gensets that get moved around a lot. Units that are in rental fleets or are on pump jack applications tend to move from site to site and may or may not have a suitable natural gas supply. Instead of paying for costly diesel to run a temporary generator, a propane system fitted to the generator set will allow for lower operational costs from the beginning because propane costs less than diesel. Furthermore, in the future, if the next site has access to natural gas, the fuel costs will drop to a fraction of that if the generator set were running on diesel.
These and other reasons make a compelling argument for opting for a natural gas / propane dual fuel system for your next spark ignited industrial generator set. For more information on the AltaStream Automatic Dual Fuel System (ADFS) and other great products, please contact us.