Saving Energy with Liquid Methionine when Pelleting

This conclusion on the beneficial impact of liquid methionine was obtained in two trials conducted in TECALIMAN, the French technical center for Feed, in their pilot pellet mill (2016 and 2020). Theses tests assess the pelleting behavior of complete feed by varying formula and methionine sources (liquid or powder) on equimolar basis, given the concentrations of each methionine product (DL-Methionine at 99% concentration and liquid OH-Methionine at 88% concentration).
Electricity consumption of pelleting is obtained by measuring the instantaneous power absorbed (kW) by the motor of the press each second. Only the values in which pelleting conditions are stable are used. This amount is then divided by the real output rate (t/h) to calculate the specific energy consumption (kWh/t). In the second trial, the results are expressed in net specific consumption by deducing the idle operation of the machine.

Feed batches are prepared using the same diet based on wheat (40%), soybean meal (30%) and corn (23%) with variation of oil quantity. DL-Methionine (DL-Met) and liquid OH-Methionine (OH-Met) are added at a standard dose on equimolar basis (0.20% for DL-Met and 0.23% for liquid OH-Met).

For the trial, the pellet quality is generally maintained. Values range at 91% ± 0.8% for durability (Eurotest-SABE device) and at 34 N/pellet ± 3.3 N/pellet for hardness (Schleuniger) for feed without oil.

The trial points to an effective reduction in energy consumption with liquid OH-Methionine (Figure 1). The reduction phenomenon is particularly observed when no other liquids are added to the formulation (Dry feed). Here, a 7% reduction is obtained. As expected, the addition of oil reduces the overall energy consumption. When 3% is added, savings when using liquid OH-Met instead of DL-Met account for 4%.

For this trial conducted in 2020 in TECALIMAN, different types of formula (wheat-based formula and one based on corn) are produced, as shown in Table 1.

Each formula is supplemented either by liquid OH-Methionine or DL-Methionine on an equimolar basis to obtain 2.5 kg of active substance per ton of feed. Each configuration (composition & methionine source) is repeated 3 times.

For formula A, C and D, a significant decrease of net energy consumption of respectively: 8%, 13% and 12% is observed when methionine is brought as liquid OH-Methionine vs DL-Methionine (Figure 2).

No significant effect has been determined between methionine sources on specific net electricity consumption for formula B and E. As the formula E contains the highest contents in oil & water, its composition leads to soften the potential differences, thus the effect of methionine sources may be negligible. We cannot explain why no significant difference is observed on formula B. On pellet hardness, durability and rate of fines, no impact is determined between pellets.

Overall, pilot trials show an advantage in power consumption for liquid OH-Met with values up to 13% less compared to DL-Met. Same conclusions are obtained in the field, for example in two different Malaysian feed mills comparing the two sources of methionine in 2015. On a formula composed mainly of corn and soybean meal, the specific pelleting power consumption was 2.5% inferior when using liquid OH-Met instead of DL-Met.

This advantage is not seen in every case, but the electricity consumption for pelleting is a least the same than for feed with DL-Met or even lower, i.e. better. Seeing this advantage from another angle, it means that, at a constant power, the flowrate of the pellet mill may be increased by a few percent when using liquid methionine compared to DL-Met. For the feed miller, these potential savings will reflect on the cost of feed production.

Adapted from Milling & Grain article, April 2021: SAVING ENERGY WITH LIQUID METHIONINE WHEN PELLETING