Ultra-long thermally insulated pipeline and forming method thereof

Abstract

The present invention provides an ultra-long thermally insulated pipeline, which includes a working steel pipe and an outer sleeve steel pipe sleeving the working steel pipe, where an annular vacuum cavity is formed between the working steel pipe and the outer sleeve steel pipe; two ends of the outer sleeve steel pipe are tightened; and the tightened parts of the outer sleeve steel pipe are sealed with an outer wall of the working steel pipe through a plurality of sealing rings. The ultra-long thermally insulated pipeline further includes a spiral ring supporting frame which is disposed outside the working steel pipe and is in contact with a wall of the working steel pipe. The spiral ring supporting frame is made of a phase change material The present invention further provides a forming method of an ultra-long thermally insulated pipeline.

Claims

1. An ultra-long thermally insulated pipeline, comprising a working steel pipe and an outer sleeve steel pipe sleeving the working steel pipe, wherein an annular vacuum cavity is formed between the working steel pipe and the outer sleeve steel pipe; two ends of the outer sleeve steel pipe are tightened; and the two ends of the outer sleeve steel pipe are sealed with an outer wall of the working steel pipe through a plurality of sealing rings; wherein the ultra-long thermally insulated pipeline further comprises: a spiral-ring-shaped supporting frame which is disposed outside the working steel pipe and is in contact with a wall of the working steel pipe, the spiral-ring-shaped supporting frame is made of a phase change material, and the phase change material comprises: 20-30 parts by weight of paraffin phase change microcapsules, wherein a capsule core of the paraffin phase change microcapsules is made of paraffin, a capsule wall is made of a polymer of methyl methacrylate and styrene, and a molar ratio of the methyl methacrylate to the styrene is (3-5):1; 50-100 parts by weight of elastomer; and 50-100 parts by weight of binder.

2. The ultra-long thermally insulated pipeline according to claim 1, further comprising an inorganic thermal insulation material layer disposed outside the working steel pipe, wherein the inorganic thermal insulation material layer is compounded with the spiral-ring shaped supporting frame.

3. The ultra-long thermally insulated pipeline according to claim 2, further comprising an anti-corrosive layer disposed on an outer wall of the outer sleeve steel pipe.

4. The ultra-long thermally insulated pipeline according to claim 3, wherein the inorganic thermal insulation material layer comprises: 20-40 parts by weight of nano alumina ceramic microspheres; 10-20 parts by weight of hollow glass microspheres; 10-20 parts by weight of paraffin phase change microcapsules, wherein a capsule core of the paraffin phase change microcapsules is made of paraffin, a capsule wall is made of a polymer of methyl methacrylate and styrene, and a molar ratio of the methyl methacrylate to the styrene is (3-5):1; 5-10 parts by weight of reinforced fibers; 50-80 parts by weight of binder; and 10-20 parts by weight of water glass.

5. The ultra-long thermally insulated pipeline according to claim 3, wherein the annular vacuum cavity has a thickness of 3-10 mm; and the thermally insulated pipeline has a length of 1000-8000 m.

6. The ultra-long thermally insulated pipeline according to claim 3, further comprising a glass fiber aluminum foil layer disposed between the inorganic thermal insulation material layer and the outer sleeve steel pipe.

7. The ultra-long thermally insulated pipeline according to claim 2, wherein the inorganic thermal insulation material layer comprises: 20-40 parts by weight of nano alumina ceramic microspheres; 10-20 parts by weight of hollow glass microspheres; 10-20 parts by weight of paraffin phase change microcapsules, wherein a capsule core of the paraffin phase change microcapsules is made of paraffin, a capsule wall is made of a polymer of methyl methacrylate and styrene, and a molar ratio of the methyl methacrylate to the styrene is (3-5):1; 5-10 parts by weight of reinforced fibers; 50-80 parts by weight of binder; and 10-20 parts by weight of water glass.

8. The ultra-long thermally insulated pipeline according to claim 2, wherein the annular vacuum cavity has a thickness of 3-10 mm; and the thermally insulated pipeline has a length of 1000-8000 m.

9. The ultra-long thermally insulated pipeline according to claim 2, further comprising a glass fiber aluminum foil layer disposed between the inorganic thermal insulation material layer and the outer sleeve steel pipe.

10. The ultra-long thermally insulated pipeline according to claim 1, further comprising an anti-corrosive layer disposed on an outer wall of the outer sleeve steel pipe.

11. The ultra-long thermally insulated pipeline according to claim 10, wherein the inorganic thermal insulation material layer comprises: 20-40 parts by weight of nano alumina ceramic microspheres; 10-20 parts by weight of hollow glass microspheres; 10-20 parts by weight of paraffin phase change microcapsules, wherein a capsule core of the paraffin phase change microcapsules is made of paraffin, a capsule wall is made of a polymer of methyl methacrylate and styrene, and a molar ratio of the methyl methacrylate to the styrene is (3-5):1; 5-10 parts by weight of reinforced fibers; 50-80 parts by weight of binder; and 10-20 parts by weight of water glass.

12. The ultra-long thermally insulated pipeline according to claim 10, wherein the annular vacuum cavity has a thickness of 3-10 mm; and the thermally insulated pipeline has a length of 1000-8000 m.

13. The ultra-long thermally insulated pipeline according to claim 10, further comprising a glass fiber aluminum foil layer disposed between the inorganic thermal insulation material layer and the outer sleeve steel pipe.

14. The ultra-long thermally insulated pipeline according to claim 1, wherein the inorganic thermal insulation material layer comprises: 20-40 parts by weight of nano alumina ceramic microspheres; 10-20 parts by weight of hollow glass microspheres; 10-20 parts by weight of paraffin phase change microcapsules, wherein a capsule core of the paraffin phase change microcapsules is made of paraffin, a capsule wall is made of a polymer of methyl methacrylate and styrene, and a molar ratio of the methyl methacrylate to the styrene is (3-5):1; 5-10 parts by weight of reinforced fibers; 50-80 parts by weight of binder; and 10-20 parts by weight of water glass.

15. The ultra-long thermally insulated pipeline according to claim 1, wherein the annular vacuum cavity has a thickness of 3-10 mm; and the thermally insulated pipeline has a length of 1000-8000 m.

16. A forming method of an ultra-long thermally insulated pipeline, comprising the following steps: a): curling and welding a steel plate used for a working steel pipe into a pipe, and performing heat treatment to obtain a working steel pipe; b): making a phase change material into a spiral-ring shaped supporting frame on an outer wall of the working steel pipe, wherein the phase change material comprises: 20-30 parts by weight of paraffin phase change microcapsules, wherein a capsule core of the paraffin phase change microcapsules is made of paraffin, a capsule wall is made of a polymer of methyl methacrylate and styrene, and a molar ratio of the methyl methacrylate to the styrene is (3-5):1; 50-100 parts by weight of elastomer; and 50-100 parts by weight of binder; c) curling a steel plate used for an outer sleeve steel pipe; wrapping, on an inner side of the steel plate, the working steel pipe with the outer wall provided with the spiral-ring-shaped supporting frame in the curling process, welding and sealing the working steel pipe into a sleeve with an annular cavity, and performing heat treatment on the sleeve; d): placing a plurality of rubber rings at two ends of the outer sleeve steel pipe for sealing, vacuumizing the annular cavity, and welding and sealing the ports of the outer sleeve steel pipe; and e): performing heat treatment on the welded and sealed pipeline.

17. The forming method according to claim 16, wherein after step b2), the method further comprises: b3): coating the outer wall of the working steel pipe with an inorganic thermal insulation material, and forming an inorganic thermal insulation material layer after curing, wherein the inorganic thermal insulation material comprises: 20-40 parts by weight of nano alumina ceramic microspheres; 10-20 parts by weight of hollow glass microspheres; 10-20 parts by weight of paraffin phase change microcapsules, wherein a capsule core of the paraffin phase change microcapsules is made of paraffin, a capsule wall is made of a polymer of methyl methacrylate and styrene, and a molar ratio of the methyl methacrylate to the styrene is (3-5):1; 5-10 parts by weight of reinforced fibers; 50-80 parts by weight of binder; and 10-20 parts by weight of water glass.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic cross-sectional structural diagram of an ultra-long thermally insulated pipeline provided by Embodiment 1 of the present invention;

(2) FIG. 2 is a schematic cross-sectional structural diagram of an ultra-long thermally insulated pipeline provided by Embodiment 2 of the present invention;

(3) FIG. 3 is a view from one end of a working steel pipe; and

(4) FIG. 4 is a view from one end of an outer sleeve steel pipe.

DETAILED DESCRIPTION

(5) As shown in FIG. 1, FIG. 1 is a schematic cross-sectional structural diagram of an ultra-long thermally insulated pipeline provided by Embodiment 1 of the present invention. Provided are a working steel pipe 1, an outer sleeve steel pipe 2, a spiral ring supporting frame 3 in contact with a wall of the working steel pipe 1, and an inorganic thermal insulation material layer 4 compounded with the spiral ring supporting frame 3 and filling between the outer sleeve steel pipe 2 and the working steel pipe 1. As illustrated in FIG. 3, two ends 7 of the outer sleeve steel pipe are tightened; and the tightened parts of the outer sleeve steel pipe are sealed with an outer wall of the working steel pipe through a plurality of sealing rings 6.

(6) As shown in FIG. 2, FIG. 2 is a schematic cross-sectional structural diagram of an ultra-long thermally insulated pipeline provided by Embodiment 2 of the present invention. Provided are a working steel pipe 1, an outer sleeve steel pipe 2, a spiral ring supporting frame 3 in contact with a wall of the working steel pipe 1, an inorganic thermal insulation material layer 4 compounded with the spiral ring supporting frame 3 and filling in an interlayer between the outer sleeve steel pipe 2 and the working steel pipe 1, and a glass fiber aluminum foil layer 5 disposed between the inorganic thermal insulation material layer 4 and the outer sleeve steel pipe 2.

(7) In the following embodiments, paraffin phase change microcapsules were prepared according to the following method including:

(8) dissolving an emulsifier in water to form a water phase, where the emulsifier is prepared by compounding Span 80 and Tween 80 at a weight ratio of 1:2; dissolving paraffin wax and a wall material into an oil phase; mixing the water phase with the oil phase, and shearing at a high speed of 6000 rpm for 10 min to form a stable emulsion; adding hydrogen peroxide and sodium bisulfite, and reacting at 25° C. for 5 h to obtain paraffin phase change microcapsules.

Embodiment 1

(9) A steel plate used for a working steel pipe was cleaned in an ultrasonic cleaning tank three times in turn by sodium dodecyl benzene sulfonate and clear water, air-dried and then curled, and welded into a pipe with an inner diameter of 31 mm in one time by laser; then the pipe was heated at 700° C. for 20 min, cooled in a hydrogen atmosphere, and tempered at 550° C. to obtain a working steel pipe, where the working steel pipe was made of stainless steel and its main components were as follows: 0.019% of C, 0.49% of Si, 1.25% of Mn, 0.022% of P, 0.00005% of S, 5.16% of Ni, 22.46% of Cr, 0.163% of N, 0.003% of Cu, 3.07% of Mo, and the balance Fe.

(10) 80 parts by weight of elastomer TPU was melted, 20 parts by weight of paraffin phase change microcapsules were added and evenly mixed and then a spiral ring elastomer was formed, and then the spiral ring elastomer was bonded on an outer wall of the working steel pipe by using 100 parts by weight of polyester to form a spiral ring supporting frame.

(11) A steel plate used for an outer sleeve steel pipe was cleaned in an ultrasonic cleaning tank three times in turn by sodium dodecyl benzene sulfonate and clear water, air-dried and then curled, and the working steel pipe with the outer wall provided with the spiral ring supporting frame was wrapped on an inner side of the steel plate in the curling process; after the wrapping, the steel plate was welded and sealed into a sleeve by laser welding, where an annular cavity between the outer wall of the working steel pipe and an inner wall of the outer sleeve steel pipe had a thickness of 7 mm; and the sleeve obtained by welding was heated at 700° C. for 20 min, cooled in a hydrogen atmosphere, and tempered at 550° C. to obtain a working steel pipe, where the working steel pipe was made of TA18 titanium alloy and its main components were as follows: 3.5% of Al, 2.0% of V, 0.25% of Fe, 0.05% of C, 0.05% of N, 0.015% of H, 0.12% of O, and the balance Ti.

(12) A plurality of rubber rings were placed at tightened ports of the outer sleeve steel pipe of the sleeve for sealing, the annular cavity was vacuumized to form an annular vacuum cavity, and finally the ports of the outer sleeve steel pipe were welded and sealed.

(13) The obtained sleeve was subjected to heat treatment; specifically, heat treatment was performed at 100° C. for 60 min, then the sleeve was air-cooled to room temperature, and finally the sleeve was coated with an anti-corrosive liquid to form an anti-corrosive layer 8 (see FIG. 4) with a thickness of 0.1 mm, so that a 3000-meter-long thermally insulated pipeline was obtained. The anti-corrosive liquid included 55 parts by weight of silicone oil, 25 parts by weight of zinc powder, 2 parts by weight of citric acid, 7 parts by weight of epoxy resin, 3 parts by weight of alumina, 3 parts by weight of diatomite and 8 parts by weight of polyacrylamide.

(14) A capsule core of the paraffin phase change microcapsules was made of paraffin, and a capsule wall was made of a polymer of methyl methacrylate and styrene at a molar ratio of 3:1.

Embodiment 2

(15) A steel plate used for a working steel pipe was cleaned in an ultrasonic cleaning tank three times in turn by sodium dodecyl benzene sulfonate and clear water, air-dried and then curled, and welded into a pipe with an inner diameter of 31 mm in one time by laser; then the pipe was heated at 700° C. for 20 min, cooled in a hydrogen atmosphere, and tempered at 550° C. to obtain a working steel pipe, where the working steel pipe was made of stainless steel and its main components were as follows: 0.019% of C, 0.49% of Si, 1.25% of Mn, 0.022% of P, 0.00005% of S, 5.16% of Ni, 22.46% of Cr, 0.163% of N, 0.003% of Cu, 3.07% of Mo, and the balance Fe.

(16) 80 parts by weight of elastomer TPU was melted, 20 parts by weight of paraffin phase change microcapsules were added and evenly mixed and then a spiral ring elastomer was formed, and then the spiral ring elastomer was bonded on an outer wall of the working steel pipe by using 100 parts by weight of polyester to form a spiral ring supporting frame.

(17) The outer wall of the working steel pipe was coated with an inorganic thermal insulation material, the inorganic thermal insulation material partially wrapped the spiral ring supporting frame, and an inorganic thermal insulation material layer was formed after curing, where part of the spiral ring supporting frame was wrapped in the inorganic thermal insulation material layer, and part of the spiral ring supporting frame was exposed outside the inorganic thermal insulation material layer, where the inorganic thermal insulation material layer included 20 parts by weight of nano alumina ceramic microspheres with a particle diameter of 100-200 nm, 10 parts by weight of hollow glass microspheres with a particle diameter of 100-200 nm, 15 parts by weight of paraffin phase change microcapsules, 8 parts by weight of reinforced fibers, 80 parts by weight of polyester and 15 parts by weight of water glass.

(18) A steel plate used for an outer sleeve steel pipe was cleaned in an ultrasonic cleaning tank three times in turn by sodium dodecyl benzene sulfonate and clear water, air-dried and then curled, and the working steel pipe with the outer wall provided with the spiral ring supporting frame and the inorganic thermal insulation material layer was wrapped on an inner side of the steel plate in the curling process; after the wrapping, the steel plate was welded and sealed into a sleeve by laser welding, where an annular cavity between the inorganic thermal insulation material layer and an inner wall of the outer sleeve steel pipe had a thickness of 7 mm; and the sleeve obtained by welding was heated at 700° C. for 20 min, cooled in a hydrogen atmosphere, and tempered at 550° C. to obtain a working steel pipe, where the working steel pipe was made of TA18 titanium alloy and its main components were as follows: 3.5% of Al, 2.0% of V, 0.25% of Fe, 0.05% of C, 0.05% of N, 0.015% of H, 0.12% of O, and the balance Ti.

(19) A plurality of rubber rings were placed at tightened ports of the outer sleeve steel pipe of the sleeve for sealing, the annular cavity was vacuumized to form an annular vacuum cavity, and finally the ports of the outer sleeve steel pipe were welded and sealed.

(20) The obtained sleeve was subjected to heat treatment; specifically, heat treatment was performed at 100° C. for 60 min, then the sleeve was air-cooled to room temperature, and finally the sleeve was coated with an anti-corrosive liquid to form an anti-corrosive layer with a thickness of 0.1 mm, so that a 3000-meter-long thermally insulated pipeline was obtained. The anti-corrosive liquid included 55 parts by weight of silicone oil, 25 parts by weight of zinc powder, 2 parts by weight of citric acid, 7 parts by weight of epoxy resin, 3 parts by weight of alumina, 3 parts by weight of diatomite and 8 parts by weight of polyacrylamide.

(21) A capsule core of the paraffin phase change microcapsules was made of paraffin, and a capsule wall was made of a polymer of methyl methacrylate and styrene at a molar ratio of 3:1.

Embodiment 3

(22) This embodiment is different from Embodiment 1 in that a thermally insulated pipeline which was 5000 meters long was prepared, and a spiral ring supporting frame mainly included 30 parts by weight of paraffin phase change microcapsules, 80 parts by weight of elastomer TPU and 80 parts by weight of binder polyester.

(23) A capsule core of the paraffin phase change microcapsules was made of paraffin, and a capsule wall was made of a polymer of methyl methacrylate and styrene at a molar ratio of 5:1.

Embodiment 4

(24) This embodiment is different from Embodiment 3 in that the outer wall of the working steel pipe was further coated with an inorganic thermal insulation material, the inorganic thermal insulation material partially wrapped the spiral ring supporting frame, and an inorganic thermal insulation material layer was formed after curing, where part of the spiral ring supporting frame was wrapped in the inorganic thermal insulation material layer, and part of the spiral ring supporting frame was exposed outside the inorganic thermal insulation material layer, where the inorganic thermal insulation material layer included 25 parts by weight of nano alumina ceramic microspheres with a particle diameter of 200-400 nm, 15 parts by weight of hollow glass microspheres with a particle diameter of 100-200 nm, 10 parts by weight of paraffin phase change microcapsules, 8 parts by weight of reinforced fibers, 60 parts by weight of binder polyester and 15 parts by weight of water glass.

Embodiment 5

(25) This embodiment is different from Embodiment 1 in that a thermally insulated pipeline which was 8000 meters long was prepared, and a spiral ring supporting frame mainly included 25 parts by weight of paraffin phase change microcapsules, 100 parts by weight of elastomer TPU and 80 parts by weight of binder polyester.

(26) A capsule core of the paraffin phase change microcapsules was made of paraffin, and a capsule wall was made of a polymer of methyl methacrylate and styrene at a molar ratio of 4:1.

Embodiment 6

(27) This embodiment is different from Embodiment 5 in that the outer wall of the working steel pipe was further coated with an inorganic thermal insulation material, the inorganic thermal insulation material partially wrapped the spiral ring supporting frame, and an inorganic thermal insulation material layer was formed after curing, where part of the spiral ring supporting frame was wrapped in the inorganic thermal insulation material layer, and part of the spiral ring supporting frame was exposed outside the inorganic thermal insulation material layer, where the inorganic thermal insulation material layer included 35 parts by weight of nano alumina ceramic microspheres with a particle diameter of 200-400 nm, 20 parts by weight of hollow glass microspheres with a particle diameter of 100-200 nm, 10 parts by weight of paraffin phase change microcapsules, 8 parts by weight of reinforced fibers, 60 parts by weight of binder polyester and 12 parts by weight of water glass.

Comparative Example 1

(28) An 8000 meter thermally insulated pipeline was prepared according to the method disclosed in Embodiment 4 of CN109578752A.

Comparative Example 2

(29) A thermally insulated pipeline which was 8000 meters long was prepared by using the method of Embodiment 5. The difference was that a spiral ring supporting frame mainly included 125 parts by weight of elastomer TPU and 80 parts by weight of binder polyester.

Comparative Example 3

(30) A thermally insulated pipeline which was 8000 meters long was prepared by using the method of Embodiment 5. The difference was that a spiral ring supporting frame mainly included 25 parts by weight of paraffin phase change microcapsules, 100 parts by weight of elastomer TPU and 80 parts by weight of binder polyester.

(31) A capsule core of the paraffin phase change microcapsules was made of paraffin, and a capsule wall was made of polymethyl methacrylate.

Comparative Example 4

(32) A thermally insulated pipeline which was 8000 meters long was prepared by using the method of Embodiment 5. The difference was that a spiral ring supporting frame mainly included 25 parts by weight of paraffin phase change microcapsules, 100 parts by weight of elastomer TPU and 80 parts by weight of binder polyester.

(33) A capsule core of the paraffin phase change microcapsules was made of paraffin, and a capsule wall was made of polystyrene.

(34) The thermally insulated pipelines provided in Embodiments 1 to 5 and Comparative Examples 1 to 4 were used to respectively simulate underground working environments to exploit heat sources. Temperatures of extracted water were set to 250° C., 200° C. and 150° C., respectively. The thermally insulated pipelines prepared in Embodiments 1 to 2 were used to extract water of 150° C. The external environment of the pipelines simulated the temperature from underground 3000 meters to the earth's surface (the pipelines were set to go into the underground 3000 meters deep to extract water of 150° C.). The pipelines were subjected to stepped heating until the tops of the pipelines were at room temperature. Similarly, the thermally insulated pipelines prepared in Embodiments 3 to 4 were used to extract water of 200° C., and the thermally insulated pipelines prepared in Embodiment 5 to 6 and Comparative Examples 1 to 4 were used to extract water of 250° C., with a flow rate of 1.72 m.sup.3/h. The simulation was performed five times continuously. The results are shown in Table 1.

(35) TABLE-US-00001 TABLE 1 Test results of temperatures of water extracted from thermally insulated pipeline prepared by embodiments of the present invention and comparative examples Embodi- Embodi- Embodi- Embodi- Embodi- Embodi- Comparative Comparative Comparative Comparative ment 1 ment 2 ment 3 ment 4 ment 5 ment 6 Example 1 Example 2 Example 3 Example 4 Temperature (° C.) 144 146 195 197 243 247 198 201 218 215 of water extracted for the first time Temperature (° C.) 146 148 197 198 245 248 202 206 223 221 of water extracted for the second time Temperature (° C.) 147 148 197 198 246 248 208 211 232 225 of water extracted for the third time Temperature (° C.) 147 148 198 198 248 249 215 218 237 231 of water extracted for the fourth time Temperature (° C.) 149 150 199 200 249 249 218 221 241 236 of water extracted for the fifth time

(36) As can be seen from Table 1, the thermal insulation effect of the thermally insulated pipeline provided by the present invention is better.

(37) At the same time, after simulating for five times, the thermally insulated pipeline was tested, and no obvious mechanical deformation was found in the working steel pipe and the outer sleeve steel pipe.

(38) The foregoing descriptions are only preferred embodiments of the present invention. It should be noted that for a person of ordinary skill in the art, several improvements and modifications may further be made without departing from the principle of the present invention. These improvements and modifications should also be deemed as falling within the protection scope of the present invention.