Straw is an energy source of farm origin and is normally obtained as a by-product from cereal and oilseed crop cultivation. The connection between the global requirement of greenhouse gas reduction and the production of straw as „waste product“ (in a situation of excessive nutrients in the field) caused NESTRO to develop and efficient combustion technology for renewable raw materials.
Our particular target was to put an economic and future-proof heating technology substituting the conventional oil or gas heating system in the hands of farmers (especially pig breeders, poultry breeders, etc.).
The average energy content of straw is 4.15 kWh/kg:
250 kg straw = 100 l fuel oil
A critical parameter for calculating the ROI period is the saving of variable costs versus fixed costs, the latter being higher at the beginning due to the investment at the beginning.
Because the cost of the inputs are distinctly lower, in particular for straw as fuel, the ROI period for heat production from cereal straw is between 4 and maximum 7 years, depending on the size of the plant.
Profitability improves substantially as soon as more heat output is needed over and above the seasonal requirement (e.g., for hot water in summer and/or heating of greenhouses, poultry breeding farms with new breeding houses, etc.) which, in turn, results in quicker ROI.
The boiler has been designed specifically for burning straw. Because primary air is supplied separately, uniform preventilation of the fuel is ensured, which improves the rate of gasification. As more secondary air is added to the flue gas, the optimum combustion temperature and therefore the best burning quality is obtained.
NESTRO straw burning plants comprise of the bale conveyor with connected bale chopper, pneumatic conveying system with straw cyclone separator and rotary air-lock as well as a straw screw for feeding the boiler, the boiler and the dust separation and filter unit with flue gas fan, and a stack. With these components, NESTRO GmbH plans and designs each plant individually – ALL FROM A SINGLE SOURCE.
Photos 1/2: The bales moving on the belt are shredded at the first step. The speeds of the belt and the shredder are synchronised electronically. The bales, from which the tying cord has been removed in a prior operation, enter the bale breaker on the belt.
Photos 3/4: Like the NESTRO reference plant at Hainchen/Thuringia, the straw heating plant can be transported in sea containers.
Photos 5/6: The exhaust temperature is kept constant (by lambda sensor), which acts as a control of the output of the downstream flue gas treatment systems (photo 4). The electronic control of the whole plant is customised by the NESTRO affiliate and control specialist NESAB GmbH . This ensures permanent constant combustion.
Your specialist consultant for straw heating plants:
Thomas Heger
Schulweg 12 36433 Moorgrund
Phone:
+49 (3695) 852541
Fax:
+49 (3695) 84622
Mobil:
+49 (151) 12018749
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Schon im Vorfeld der LIGNA 2009 hatten NESTRO und HOMAG in Zusammenarbeit mit der FH Rosenheim Luftmengenbedarf und Widerstand von HOMAG-Kantenanleim-Anlagen durch Messreihen ermittelt und dokumentiert.
NESTRO hatte auf Grundlage dieser Messdaten und Betriebsanforderungen eine energieoptimierte Absauglösung für die Kantenbearbeitung entwickelt, die während der LIGNA im Vergleich zu herkömmlichen Lösungen präsentiert wurde.
Energy from straw
