Xiping Wang USDA Forest Products Laboratory. SmallWood 2012 Conference, Flagstaff, AZ May 1-3, 2012

Transcription

1 Xiping Wang USDA Forest Products Laboratory SmallWood 2012 Conference, Flagstaff, AZ May 1-3,

2 Outline Background Recent research on heat treatment Heat treating options Temperature monitoring Thermal verification 2

3 Emerald ash borer (EAB) infestation in U.S. and Canada 3

4 Economic and environmental impact No. of Ash trees died: 40 ~50 million in Michigan; 60 million nation wide Potential economic loss: $20 billion over next 10 years if not contained Possible extensive environmental damage If EAB is not contained or eradicated, it will cost local governments and homeowners approximately $20 billion over the next 10 years to remove and replace dead and dying ash trees Possible extensive environmental damage and long term changes in the North American forest structure 4

5 Quarantine regulations Federal and state quarantine regulations limiting the movement of firewood All hardwood firewood must be heat treated before they can be moved outside of EAB quarantine zones 5

6 Heat treatment standards ISPM 15 Guidelines for regulating wood packing material in international trade Require holding a core temperature of 133 F (56 C) for a minimum of 30 minutes Heat treatment standard for EAB Current Federal regulation: 140 ºF/60 min. (160 ºF/75 min. prior to Jan 2011) State regulations: 140 ºF/60 min. or 160 ºF/75 min. 6

7 Challenges Higher heating standard Heating schedules developed for WPM are not acceptable for treating firewood Lack or insufficient heating facility (particular for small firewood producers) Lack temperature monitoring and verification capability 7

8 Recent Research (FS WERC Grant) Phase 1 ( ) Develop heat treatment schedules for firewood that meet the new heat sterilization regulations Evaluate different heat treatment options Develop heat treatment schedules and heating time tables 8

9 FPL Technical Report: FPL GTR 187 9

10 Recent Research (FS WERC Grant) Phase 2 ( ) Develop temperature monitoring systems On-site demonstration projects in Wisconsin, Indiana, and Illinois. Training workshops 10

11 FPL Technical Report: FPL GTR

12 Heat Treating Options Heat treatment with moisture reduction Kiln drying + heat treatment Dry heat (low RH) Heat treatment without moisture reduction Wet heat (high RH) Heat treating seasoned firewood Dry heat 12

13 Is kiln drying an acceptable treatment? Kiln drying alone is not a standard Kin drying does not necessarily raise the internal temperature of wood in the kiln to a temperature adequate to kill pests, or hold it there long enough to be effective for the goal Kiln drying can be an acceptable technique to meet the heat treatment standard, provided the specified time and temperature requirements are met during the process. 13

14 Temperature Monitoring Monitor kiln temperatures Monitor internal wood temperatures From largest pieces of firewood At cold spots Temperature data should be recorded at least once every 5 min and stored in a computer file 14

15 Measuring kiln temperature Resistance temperature detector (RTD) 15

16 Measuring core temperature of firewood Temperature sensors Thermocouple: A junction between two different metals that produces a voltage related to a temperature difference. 16

17 Measuring core temperature of firewood - Data logger HOBO U12 Stainless temp data logger Measurement range: -40 º to 125 ºC Operating temperature: -40 º to 125 ºC 17

18 Recording temperature data Real time monitoring 8 Channel temp data logger 18

19 Recording temperature data Stand-alone data logger 19

20 Temperature monitoring system Example 1 a a Thermal mapping c c b b 20

21 Temperature monitoring system Example 2 Hot water boiler fueled with waste wood. Hold 27 baskets (14 cords firewood) 21

22 Cost of monitoring system $1,000 $2,000 Thermocouple sensors Data loggers Computer is essential Initial data logger Download temperature data Real time monitoring 22

23 Operating procedure 23

24 1. Initiate data logger/recording device

25 2. Select firewood samples 4 25

26 2. Install temperature sensors Power drill 1/8 drill bit Silicone sealant Toothpicks 26

27 3. Place samples in the bins (cold spots) 27

28 4.Complete loading & start heating 28

29 5. Monitor temperatures Periodically monitor the kiln temp and the core temperatures of firewood Determine completion of heat treatment cycle 29

30 Thermal Verification Provide a record of heat treatment that identifies each sensor and indicates time and temperature Temperature data record with time stamp Temperature profile Examine if the center temperatures of all samples reached the required temperature for the time duration. 30

31 Temperature data record 31

32 Demonstration: Direct fired kiln 32

33 Demonstration: Hot water boiler 33

34 Implementation issue Significant operation errors exist in current temperature monitoring procedure Samples, sensors, human 34

35 Current Research (USFS Grant) Phase 3 ( ) Develop generic thermal verification guidelines that are primarily based on kiln conditions, eliminating most operator errors that exist in current heat treatment practices. Increase efficiency of heat treatment in commercial firewood operations. 35

36 Questions? 36