Simplicity is efficiency. Analyzing Moisture Content by Using Magnetic Resonance Technology
Magnetic Resonance Moisture Why biofuel moisture measurement is important? Moisture of fuel increases total mass of incoming fuel but decreases the real heat content Actual decrease of the heat value decreases the value of the fuel track 100 Constant truck volume Truck heat content & total mass vs moisture % Heat content of truck total mass of truck 60.0 Truck value vs moisture (value of chips 17 /MWh) 1700 95 55.0 1600 Truck heat content MWh 90 85 80 50.0 45.0 40.0 35.0 30.0 ton 1500 1400 1300 1200 Truck value vs moisture 75 25.0 1100 70 30 35 40 45 50 55 60 65 Moisture % 20.0 1000 30 35 40 45 50 55 60 65 Moisture % 2
Magnetic Resonance Moisture Measurement Why use MR-technology for moisture measurement? A compact, low-cost, fast wood moisture measurement device that requires only one calibration for all sample materials is needed Excluding the oven drying measurement method which is slow, MR (Magnetic Resonance) seems to be the only technology that fulfills the one-calibration requirement The technology can be used to measure the moisture content of almost any material containing water MR technology is fast and reliable for moisture measurement 3
Magnetic Resonance Moisture Measurement Where did the measurement come from? Magnetic Resonance Imaging devices used in the medical industry apply a radio frequency (RF) pulse that is specific only to hydrogen When the pulse is applied, the unmatched protons absorb the energy and spin again in a different direction. This is the resonance part of the MRI. The purpose of the RF pulse is the excitation of the resonance. The specific frequency of resonance is called the Larmor frequency and is calculated based on the particular tissue being imaged and the strength of the main magnetic field When the RF pulse is turned off, the hydrogen protons slowly return to their natural alignment within the magnetic field and release energy absorbed from the RF pulses When they release this energy a radio frequency signal is generated, which can be measured with receiver coils 4
Magnetic Resonance Moisture Measurement Where did the measurement come from? MRI machines make use of the fact that body tissue contains lots of water and hence hydrogen atoms, which get aligned in a large magnetic field Hydrogen nuclei have a Nuclear Magnetic Resonance signal. MR Imaging primarily images the NMR signal from the hydrogen nuclei Magnetic resonance imaging (MRI) used in the medical industry is a test that uses a magnetic field and pulses of radio wave energy to make pictures of organs and structures inside the body The Magnetic Resonance moisture analyzer is using the magnetic resonance portion of these devices to measure the amount of moisture in a sample. 5
Basics of Magnetic Resonance The atomic nuclei of a water molecule have a spin which have a magnetic moment similar to small permanent magnets 6
Basics of Magnetic Resonance Individual hydrogen nuclei in an external field B 0 orientates parallel to the magnetic field when the magnet is applied to the sample Once the nuclei are aligned, a radio frequency (RF) pulse that is specific to hydrogen is also applied to the sample. This makes the hydrogen nuclei turn 90º and start rotating in phase. 7
Basics of Magnetic Resonance If you plot the current that it produces as a function of time it will produce a sine wave that indicates the nuclear echo signal The three curves shown below are from samples containing 200, 400, and 700 grams of water If you measure the magnitude of the signal as shown in the first figure, or plot the magnitude versus time as illustrated in the second figure, the magnitude of the sine wave will correspond to the amount of water in the sample 30 20 200g water 400g water 700g water 30 25 200g water 400g water 700g water 10 20 0 15-10 10-20 5 8-30 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 0 0 1000 2000 3000 4000 5000 6000 7000 8000 9000
Moisture measurement of a sample The Magnitude Resonance signal versus time curve is used to determine the mass of the water in the sample The mass of the water is compared to the total mass of the sample in order to determine the moisture percentage of the sample
How accurately does MR Moisture measure the actual water content 100 Test with dried saw dust water addition (5-500g) 90 80 70 Moisture % 60 50 40 MR moisture measured Calculated moisture 30 20 10 0 saw dust_5 saw dust_10 saw dust_20 saw dust_35 saw dust_55 saw dust_75 saw saw saw saw dust_115 dust_160 dust_300 dust_500 10 Date Author Title
Magnetic Resonance Moisture Measurement The accuracy has been improved to +/- 1% with improvements in the measurement and slightly longer measurement time Magnetic resonance moisture analyzer vs. oven dry method; wood based fuels. 76.0 MR moisture reading (m-%) 68.0 60.0 52.0 44.0 36.0 28.0 20.0 Fuels: -Sawdust (n=12) -Pine bark (n=3) -Wood chips (n=15) -Shavings (n=7) -Recycled wood (n=5) -Pellets (n=18) 12.0 4.0 4.0 12.0 20.0 28.0 36.0 44.0 52.0 60.0 68.0 76.0 Oven dry method moisture reading (m-%) MR-reading, 3 measurements averaged Optimum response 11
Wood based bio fuel (wood chips, wood residue etc) 90 80 70 limits+/- 1 % MR moisture % 60 50 hake 40 30 20 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 oven drying % 12 Date Author Title
Different wood species moisture % 70.0 60.0 50.0 Limits+/- 1 % MR Moisture % 40.0 30.0 Eucalyptus DF-C Acasia Cedar Linear (Series7) 20.0 10.0 0.0 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 LAB oven drying moisture % 13 Date Author Title
Saw dust moisture % 70.00 65.00 60.00 MR Moisture % 55.00 50.00 45.00 Limits+/- 1 % Saw dust 40.00 35.00 30.00 30.00 35.00 40.00 45.00 50.00 55.00 60.00 65.00 70.00 LAB oven drying moisture %) 14 Date Author Title
Wood bark moisture % 70.00 65.00 60.00 Limits +/- 1 % MR Moisture% 55.00 50.00 45.00 40.00 40.00 45.00 50.00 55.00 60.00 65.00 70.00 LAB oven drying moisture % 15 Date Author Title
Local results - NA Pulp Mill
What happens inside when measuring? Measuring water content with MR method Moisture % result Magnetic field 30 20 200g water 400g water 700g water M a g n e t R F m e a s c o i l Sample container Scale R F m e a s c o i l M a g n e t 10 0-10 -20-30 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 Water measured by MR M w =206.49g Measuring sample mass Sample total mass measured with integrated scale built into the device. Total mass with a scale: M s =512.14g Moisture: M w /M s * 100% = (206.49 g/512.14 g *100% = 40.32 %) 17
How does the MR compare to other known moisture measurement methods? Same calibration applies to all materials (unique for fast methods) Can be calibrated using only one sample containing only water Fast and accurate Competitive cost compared to IR, microwaves, etc. Measurement of frozen samples with restrictions as with most other methods Currently cannot differentiate oils from water 18
Magnetic Resonance Moisture Highlights It s fast - Measuring time 30 seconds ~ 2 minutes - No transportation of samples from source to laboratory It s reliable - +/- 1 moisture % measuring accuracy within the 10-90% range - Reliable calibration with water - Challenges oven drying method in accuracy, sample volume, and speed It s easy to use - Insert sample in the provided container - Easy touch-screen user interface - Low maintenance no moving or wearing parts It s versitile - Can measure the moisture content of almost any material containing water Results are reported as moisture or solid content 19
Metso MR Moisture Simplicity is efficiency Customers Power plants using biofuels Pulp and paper mills Mineral processing Laboratories Other industries Key benefits Fast Accurate Easy to use Low maintenance Simple calibration Large sample volumes Measurements from a wide variety of materials Saves money Biofuel moisture End product quality Minimize process disturbances Saves time Fast measurement Easy usability Design for use outside laboratory conditions No sample transportation to lab Saves resources Can be operated by anyone Easy to transport to where it s needed 20 Metso Date Author Title