Fuel selection for mobile batch grain driers – Part 1
Farmers looking at buying batch grain driers often ask which fuel Mecmar grain driers use. The answer is straightforward; we supply driers with diesel, gas or kerosene burners. All are clean and efficient fuels for grain drying. The next question is usually along the lines of, so which fuel is the most economical? This is a much more complicated question to answer and one I will address in my next two posts.
The first will look at the operational cost of drying with different fuels and the second will illustrate the influence of capital expenditure on fuel economics.
The question of fuel economy for mobile batch grain driers has no definitive answer as no two situations are ever the same. So I will attempt to highlight the variables and issues to provide some guidance on how to select the most economical fuel for your farm.
The important point that must be raised when considering fuel economy is, comparison of the cost per litre of different fuels gives no direct indication of which fuel is most economical. This is because different fuels have different energy densities (MJ/l). To calculate which fuel is the most economical it is necessary to consider the different energy density of each.
As each fuel has a different energy density each require a different volume to be combusted to give the same energy output. Below are general guidelines to fuel quantity used for mobile batch grain driers though they can vary widely dependent on crop condition and atmospheric conditions:
- 1 litre of diesel is required to reduce the moisture of 1 tonne of wheat by 1%
- 1.05 litre of kerosene are required to reduce the moisture of 1 tonne of wheat by 1%
- 2.5 litres of propane gas are required to reduce the moisture of 1 tonne of wheat by 1%
So for example, if you were to dry 2,000 tonnes of wheat taking out 5% you get the following fuel consumption:
- Diesel 2,000 x 5 x 1 = 10,000l
- Kerosene 2,000 x 5 x 1.05 = 10,500l
- Propane gas 2,000 x 5 x 2.5 = 25,000l
This shows the large difference in the volume combusted for different fuels while drying the same product. Now to put a cost to this I recently priced each fuel based on a standard 2000l farm order. This gave the following costs to the above volumes:
- Diesel 10,000 x 51.60p = £5,160
- Kerosene 10,500 x 40.78p = £4,281
- Propane gas 25,000 x 36p = £9,000
This illustrates the large difference in price between each fuel to dry the same product. It is also apparent that the size of the saving is dependent on the tonnage dried and the moisture taken out. This can be seen when calculating the fuel costs of drying 500 tonnes and taking out 3% moisture
- Diesel £774
- Kerosene £642
- Propane gas £1,350
The difference in the operational fuel cost between different fuels is proportional, it will fluctuate as fuel price varies but is unlikely to alter significantly. The difference, especially when drying large tonnages from high moistures, is a significant sum and the importance of selecting the right fuel is emphasised. To fully consider fuel economy though, the capital expense of each fuel also needs to be considered. I will investigate this in my next post.