Multiplex pipe and system for recovering steam from geothermal wells
View Patent ↗Provided is a multiplex pipe and a system for recovering steam from a geothermal well, which are capable of solving all of the various problems with a neutralization pipe prepared by painting or the like of an alkali-resistant coating on the inner face of an acid-resistant single pipe. A multiplex pipe 10 that is configured to recover steam from a geothermal well GT, includes: a casing pipe 1 located outside; and a duplex pipe 4 that is slidable relative to the casing pipe 1 in the casing pipe 1 , and has a first gap 5 with an inner face of the casing pipe 1 , the duplex pipe including an outer pipe 2 having acid-resistance and an inner pipe 3 having alkali-resistance, the outer pipe 2 and the inner pipe 3 defining a second gap 6 therebetween. An alkali solution is injected to acid hot-water stored in an acid geothermal well GT via a hollow 7 of the inner pipe 3 to neutralize the acid hot-water, and the neutralized hot-water V is allowed to spout to the ground via the first gap 5 , thus recovering flashing steam.
1. A multiplex pipe configured to recover steam from a geothermal well, comprising:
a casing pipe located outside; and
a duplex pipe that is slidable relative to the casing pipe in the casing pipe, and has a first gap with an inner face of the casing pipe, the duplex pipe including an outer pipe formed from a pipe material having acid-resistance without the use of an acid-resistance coating and an inner pipe formed from a pipe material having alkali-resistance without the use of an alkali-resistance coating, the outer pipe and the inner pipe defining a second gap therebetween;
wherein an alkali solution is injected to acid hot-water stored in an acid geothermal well via an interior of the inner pipe to neutralize the acid hot-water, and the neutralized hot-water is allowed to spout to the ground via the first gap, thus recovering flashing steam.
2. The multiplex pipe configured to recover steam from a geothermal well according to claim 1 , wherein the outer pipe comprises an alloy containing titanium as a main component, and the inner pipe comprises a fluorine-based resin.
3. The multiplex pipe configured to recover steam from a geothermal well according to claim 1 , wherein in the duplex pipe, a forward end of the inner pipe protrudes from a forward end of the outer pipe.
4. The multiplex pipe configured to recover steam from a geothermal well according to claim 1 , wherein the alkali solution injected has a specific gravity larger than a specific gravity of the acid hot-water.
5. The multiplex pipe configured to recover steam from a geothermal well according to claim 1 , wherein the outer pipe has an inner diameter of 50 mm or less, the inner pipe has a thickness of 0.2 mm or more, and the duplex pipe has a length of 2,000 to 3,000 m.
6. A system configured to recover steam from a geothermal well, comprising:
the multiplex pipe according to claim 1 ; and
a delivery device configured to send out the duplex pipe into the geothermal well while holding a state where the forward end of the inner pipe protrudes from the forward end of the outer pipe in the duplex pipe.
7. The multiplex pipe configured to recover steam from a geothermal well according to claim 2 , wherein in the duplex pipe, a forward end of the inner pipe protrudes from a forward end of the outer pipe.
8. The multiplex pipe configured to recover steam from a geothermal well according to claim 2 , wherein the alkali solution injected has a specific gravity larger than a specific gravity of the acid hot-water.
9. The multiplex pipe configured to recover steam from a geothermal well according to claim 3 , wherein the alkali solution injected has a specific gravity larger than a specific gravity of the acid hot-water.
10. The multiplex pipe configured to recover steam from a geothermal well according to claim 2 , wherein the outer pipe has an inner diameter of 50 mm or less, the inner pipe has a thickness of 0.2 mm or more, and the duplex pipe has a length of 2,000 to 3,000 m.
11. The multiplex pipe configured to recover steam from a geothermal well according to claim 3 , wherein the outer pipe has an inner diameter of 50 mm or less, the inner pipe has a thickness of 0.2 mm or more, and the duplex pipe has a length of 2,000 to 3,000 m.
12. The multiplex pipe configured to recover steam from a geothermal well according to claim 4 , wherein the outer pipe has an inner diameter of 50 mm or less, the inner pipe has a thickness of 0.2 mm or more, and the duplex pipe has a length of 2,000 to 3,000 m.
13. A system configured to recover steam from a geothermal well, comprising:
the multiplex pipe according to claim 2 ; and
a delivery device configured to send out the duplex pipe into the geothermal well while holding a state where the forward end of the inner pipe protrudes from the forward end of the outer pipe in the duplex pipe.
14. A system configured to recover steam from a geothermal well, comprising:
the multiplex pipe according to claim 3 ; and
a delivery device configured to send out the duplex pipe into the geothermal well while holding a state where the forward end of the inner pipe protrudes from the forward end of the outer pipe in the duplex pipe.
15. A system configured to recover steam from a geothermal well, comprising:
the multiplex pipe according to claim 4 ; and
a delivery device configured to send out the duplex pipe into the geothermal well while holding a state where the forward end of the inner pipe protrudes from the forward end of the outer pipe in the duplex pipe.
16. A system configured to recover steam from a geothermal well, comprising:
the multiplex pipe according to claim 5 ; and
a delivery device configured to send out the duplex pipe into the geothermal well while holding a state where the forward end of the inner pipe protrudes from the forward end of the outer pipe in the duplex pipe.
17. The multiplex pipe configured to recover steam from a geothermal well according to claim 1 , wherein a forward end of the inner pipe protrudes from a forward end of the outer pipe to define a protruding posture, and wherein the outer pipe degrades before degradation of the inner pipe, thereby maintaining the protruding posture of the inner pipe without sliding the inner pipe relative to the outer pipe.
18. The multiplex pipe configured to recover steam from a geothermal well according to claim 1 , wherein the outer pipe degrades before degradation of the inner pipe.
19. The multiplex pipe configured to recover steam from a geothermal well according to claim 1 , wherein the outer pipe degrades before degradation of the inner pipe, thereby maintaining a positional relationship of the inner pipe relative to the outer pipe.