Process and apparatus for treating lignocellulosic material

1. A process for treating lignocellulosic pieces with a water-soluble lignocellulosic material preservative, the process comprising the step of:

preparing a water-based preservative solution by dissolving the water-soluble lignocellulosic material preservative comprising disodium octaborate tetrahydrate (DOT) in a concentration above 40% wt, in water at a preparation temperature;

lowering a temperature of the water-based preservative solution from the preparation temperature to a contact temperature lower than the preparation temperature; and

submersing the lignocellulosic pieces with the water-based preservative solution at the contact temperature, the contact temperature being between 85° C. and 95° C.

2. The process of claim 1 , wherein the preservative solution contains the water-soluble lignocellulosic material preservative in a concentration between 45% wt and 50% wt.

3. The process of claim 1 , wherein the step of submersing the lignocellulosic pieces with the water-based preservative solution is performed at atmospheric pressure.

4. The process of claim 1 , further comprising the step of maintaining the treated lignocellulosic pieces in a post-conditioning environment at atmospheric pressure and having a temperature between 60° C. and 95° C. and a relative humidity between 50% and 100%.

5. The process of claim 4 , wherein the step of maintaining the chemically treated lignocellulosic pieces in the post-conditioning environment comprises the substep of exposing the chemically treated lignocellulosic pieces to a water-based post-conditioning agent having a temperature between 60° C. and 95° C.

6. The process of claim 5 , wherein the post-conditioning agent comprises water vapor.

7. The process of claim 4 , wherein the step of maintaining the chemically treated lignocellulosic pieces in the post-conditioning environment is performed between during 30 seconds and 15 minutes.

8. The process of claim 7 , wherein the step of maintaining the chemically treated lignocellulosic pieces in the post-conditioning environment is performed during 5 minutes and 12 minutes.

9. The process of claim 4 , wherein a sequence of submersing the lignocellulosic pieces with the water-based preservative solution and maintaining the chemically treated lignocellulosic pieces in the post-conditioning environment is performed a plurality of times.

10. The process of claim 1 , further comprising an initial step of maintaining the lignocellulosic pieces in a pre-conditioning environment having a temperature above the ambient temperature and a humidity level above the ambient humidity to heat and humidify the lignocellulosic pieces and the step of maintaining the lignocellulosic pieces in the pre-conditioning environment comprises the substep of exposing the lignocellulosic pieces to a water-based pre-conditioning agent having a temperature between 70° C. and 100° C. when in contact with the lignocellulosic pieces.

11. The process of claim 10 , wherein the step of maintaining the lignocellulosic pieces in a pre-conditioning environment is performed during between 30 seconds and 5 minutes and the water-based pre-conditioning agent comprises at least one of hot water and water vapor.

12. The process of claim 10 , wherein the lignocellulosic pieces have a moisture content between 10% wt and 20% wt before being maintained in the pre-conditioning environment.

13. The process of claim 1 , wherein the step of submersing the lignocellulosic pieces with the water-based preservative solution is performed during between 30 seconds and 30 minutes.

14. The process of claim 13 , wherein the step of submersing the lignocellulosic pieces with the water-based preservative solution is performed during less than 15 minutes.

15. The process of claim 1 , wherein the step of preparing the water-based preservative solution at a temperature higher than the contact temperature comprises preparing the water-based preservative solution at a temperature above 95° C. and below 100° C.

16. The process of claim 1 , wherein the lignocellulosic pieces initially comprise dried and planed lignocellulosic pieces.