Process to stop and/or prevent the spreading of peat fires

Abstract

Process to stop and/or prevent the spreading of peat fires consisting of: digging a trench in the periphery of the area of outbreak of fire or potential fire, filling the trench at least partially with a superabsorbent (co)polymer (SAP).

Claims

1. A process to stop and/or prevent the spreading of peat fire, the process comprising: digging a trench into soil of a periphery of an area of outbreak of peat fire or potential peat fire, wherein at least some peat is in the soil; and filling said trench at least partially with at least one superabsorbent (co)polymer (SAP), wherein the at least one superabsorbent (co)polymer (SAP) is an acrylamide and partially or totally salified acrylic acid crosslinked copolymer and contains between 40 and 90 mole percentage (mol %) of acrylamide and between 10 and 60 mol % of partially or totally salified acrylic acid.

2. Process according to claim 1 wherein the at least one superabsorbent (co)polymer (SAP) is partially or totally swollen with water before filling the trench.

3. Process according to claim 2 wherein the water is mixed with one or more compounds capable of improving the extinguishing ability of the said water, and wherein the one or more compounds are phosphate, bicarbonate, or urea.

4. Process according to claim 1 wherein the at least one superabsorbent (co)polymer (SAP) is deposited directly in the trench then totally or partially swollen with prior or subsequent input of water.

5. Process according to claim 4 wherein the water is mixed with one or more compounds capable of improving the extinguishing ability of the said water, wherein the one or more compounds are phosphate, bicarbonate or urea.

6. Process according to claim 1 wherein the trench is 20 to 40 centimeters wide.

7. Process according to claim 1 wherein the trench is up to 8 meters in depth.

8. Process according to claim 1 wherein the partially or totally salified acrylic acid is in the form of a sodium salt.

9. Process according to claim 1 wherein the at least one superabsorbent (co)polymer (SAP) undergoes double crosslinking by an acrylic crosslinking agent at a rate of 100 to 1,000 parts per million (ppm) and an allylic crosslinking agent at a rate of 1,000 to 5000 ppm.

10. Process according to claim 9 wherein the acrylic crosslinking agent is MBA (methylenebisacrylamide) and wherein the allylic crosslinking agent is tetra-allylammonium chloride.

11. Process according to claim 1 wherein the at least one superabsorbent (co)polymer (SAP) is mixed with 10 to 20% calcium carbonate or sodium carbonate.

12. Process according to claim 1 wherein the at least one superabsorbent (co)polymer (SAP) is continuously partially or totally swollen in successive tanks and is injected into the trench.

13. Process according to claim 1 wherein the at least one superabsorbent (co)polymer (SAP) is swollen in a processing center and transported by tanker trucks to a treatment site where the process is performed.

14. A process to stop and/or prevent the spreading of peat fire, the process comprising: digging a trench into soil of a periphery of an area of outbreak of peat fire or potential peat fire, wherein at least some of the peat is in the soil; and filling said trench at least partially with at least one superabsorbent (co)polymer (SAP), wherein the at least one superabsorbent (co)polymer (SAP) undergoes double crosslinking by an acrylic crosslinking agent at a rate of 100 to 1,000 parts per million (ppm) and an allylic crosslinking agent at a rate of 1,000 to 5000 ppm.

15. The process according to claim 14 wherein the acrylic crosslinking agent is MBA (methylenebisacrylamide) and wherein the allylic crosslinking agent is tetra-allylammonium chloride.

16. The process according to claim 14 wherein the at least one superabsorbent (co)polymer (SAP) is partially or totally swollen with water before filling the trench.

17. The process according to claim 14 wherein the at least one superabsorbent (co)polymer (SAP) is deposited directly in the trench then totally or partially swollen with prior or subsequent input of water.

18. The process according to claim 14 wherein the trench is 20 to 40 centimeters wide.

19. The process according to claim 14 wherein the trench is up to 8 meters in depth.

20. The process according to claim 14 wherein the at least one superabsorbent (co)polymer (SAP) is a crosslinked copolymer or a crosslinked polyacrylic acid, wherein: the crosslinked copolymer is a copolymer of acrylamide and partially or totally salified acrylic acid, and the crosslinked polyacrylic acid is partially or totally salified.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a representation of a chain trencher digging a trench (front and side views). FIG. 2 is a representation of the facility of the invention according to a preferred embodiment.

DESCRIPTION OF THE EXAMPLES

(2) A wheel trencher is an example allowing for trenches of a maximum depth of 1.20 m/1.50 m with a very narrow passage of approximately 10 to 20 cm.

(3) FIG. 1 represents chain trenchers allowing for trenches of up to 8 meters deep on loose ground. The trench width depends on the rigidity of the arm and is between a minimum of 20 to 40 cm. Some trenchers can go up to 1 meter and over. FIG. 2 is a representation of a facility implementing the process of the invention according to a specific embodiment.

(4) FIG. 2 shows that a trencher (1) forms the trench and evacuates the earth into a truck (2). At the rear, a truck (3) injects the swollen SAPs into the trench using a Moineau type displacement pump (4). This truck contains a hopper (5) containing the polymer, a screw dosing device (6), two swelling tanks with agitators (7) allowing for contact of the SAP with the water. At the rear of the second truck (3), a third truck (8) supplies the water via a valve and a pipeline (9) connecting the truck (8) to the swelling tanks (7).

(5) In certain cases, a set of trailers towed by a powerful tractor and including a swelling trailer, a polymer trailer and a water trailer which is filled by a substantial number of trucks, can be used. The construction of this equipment obviously depends on the service required.

(6) The quantities of (co)polymer to be inserted per trench of a width of 20 cm and 4 meters deep are 800 liters per meter usually including (medium hard water) 782 liters of water and 8 kg of polymer. The swelling time depends on the grain size of the polymer. It is approximately 1 hour for a polymer of a grain size of less than 1 mm. Sometimes bigger grain sizes of less than 4 mm are preferred with a longer swelling time (approximately 3 hours). It is possible to inject copolymers that are not fully swollen and which finish swelling in the trench with an excess of water.

(7) With a truck of 20 m.sup.3 of water, it is possible to treat a trench of 20 to 40 meters depending on the depth and thickness. This therefore requires a substantial number of water trucks.

(8) A 5-tonne container of polymer would allow for a length of 600 meters to be treated and a 20-tonne truck, 2,500 meters.

(9) The person skilled in the art could adapt this basic facility to the local characteristics.