CN1089716A - Processing method for replacing local pipe section of heat exchange pipe of high-pressure methylamine condenser - Google Patents

Processing method for replacing local pipe section of heat exchange pipe of high-pressure methylamine condenser Download PDF

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Publication number
CN1089716A
CN1089716A CN 93115355 CN93115355A CN1089716A CN 1089716 A CN1089716 A CN 1089716A CN 93115355 CN93115355 CN 93115355 CN 93115355 A CN93115355 A CN 93115355A CN 1089716 A CN1089716 A CN 1089716A
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China
Prior art keywords
exchanger tube
heat exchanger
welding
pipe
heat exchange
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Pending
Application number
CN 93115355
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Chinese (zh)
Inventor
任晓善
陈晓军
张崇恩
景新荣
许炳然
金丽江
由焕军
冯文娥
易小平
章怀异
周清木
杨文欣
杨灵
范东涛
肖银生
胡锡章
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LUZHOU NATURAL GAS CHEMICAL INDUSTRY CORP
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LUZHOU NATURAL GAS CHEMICAL INDUSTRY CORP
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Application filed by LUZHOU NATURAL GAS CHEMICAL INDUSTRY CORP filed Critical LUZHOU NATURAL GAS CHEMICAL INDUSTRY CORP
Priority to CN 93115355 priority Critical patent/CN1089716A/en
Publication of CN1089716A publication Critical patent/CN1089716A/en
Pending legal-status Critical Current

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Abstract

The invention provides a processing method for replacing a local pipe section of a heat exchange pipe of a high-pressure methylamine condenser, which is characterized in that after fillet welds at two ends of the heat exchange pipe are milled and a defective pipe section at the upper section of the heat exchange pipe is cut off, a new pipe OOCr22Ni6Mo3 or OOCr25Ni22Mo2 is selected, manual argon arc welding is adopted to enable the new pipe and the heat exchange pipe to be in butt joint, a workpiece rotates clockwise during welding, a welding gun does not arc, the pipe is installed back after welding is qualified, and after a redundant pipe section is cut off, two ends are sealed and welded. The method has the advantages of large repair capability on the defective heat exchange tube in a short period, high repair speed, greatly improved corrosion resistance of equipment and prolonged service life.

Description

Change the processing method of the local pipeline section of heat-exchanger tube of high pressure methylamine condenser
What the present invention relates to is a kind of processing method of changing the local pipeline section of heat-exchanger tube of high pressure methylamine condenser.
What the hp ammonium carbamate condenser in the CO2 vaporizing extract process urea plant adopted is vertical fixed tube-sheet exchanger.That the heat exchanger tube in the heat exchanger adopts is 316L.Stainless steel material is made.Shell-side is to contain micro-Cl -High-temperature water, heat exchanger tube outer wall maximum total stress reached the 316L stainless steel material yield limit 79~80%, under this environment, the 316L stainless steel material has stronger Sensitivity of Stress Corrosion, new equipment is established production in 2-3, stress corrosion will take place heat exchanger tube destroys, in a short time Cl in the shell-side water -Control bad large quantities of heat exchanger tubes inefficacies that just can cause.What flow in the heat exchanger tube tube side is the first ammonium medium of HTHP deep-etching, in the mill angle welding weld defect of equipment-overheated, burn, accumulation corrosion in medium all can cause equipment to leak in using, device is stopped production, and once stopping production just to produce 400,000 yuan of economic losses.Tube failure quantity reaches 10% of a total of tubes, and equipment is scrapped whole.And a present hp ammonium carbamate condenser is worth more than 1,000 ten thousand yuan.
Hp ammonium carbamate condenser is long-time use after, except that heat exchanger tube, other partly in order, even there is slight damage also easily to repair.And length is that 12 meters heat exchanger tube defective is generally all in the 0.5 meter scope in two ends.Because equipment end socket and tube sheet are welding, defectiveness heat exchanger tube present position on tube sheet generally can not be changed in whole extraction, so generally have to adopt the method for obstruction after heat exchanger tube lost efficacy, along with the plugging number is on the increase, Operational capability of plant constantly reduces, even scraps.
The beginning of the eighties, begin tentative drawing method both at home and abroad, be low according to the austenitic stainless steel yield limit, the characteristics that ductility is good, pipe end processing produces plastic deformation with external force with the heat exchanger tube pulling, clip the defectiveness pipeline section, this method for the bigger pipe of defective easily pull off, success rate is low, even success also can be owing to tube drawing produces residual stress, stress corrosion destroys in quickening to use.
In view of above reason, the objective of the invention is for a kind of processing method of changing the local pipeline section of heat-exchanger tube of high pressure methylamine condenser is provided, it is rapid to adopt this kind method to change the defective pipeline section, the service life that the pipeline section corrosion resistance after the replacing is stronger, can prolong equipment.
Processing method of the present invention is: 1, pipe end processing mills heat exchanger tube two ends angle welding and tube head; 2, take out pipe, upwards extract the heat exchanger tube epimere out the heat exchanger tube epimere is partly exposed outside the tube sheet, clip heat exchanger tube epimere defectiveness pipeline section; It is characterized in that: 3, select the processing of new material and heat exchanger tube butt joint groove, select new tubing OOCr22Ni6Mo3 or OOCr25Ni22Mo2 for use, make the length of new pipe length, process butt joint groove α=25~35 ° respectively at new tubing and heat exchanger tube joint greater than the heat exchanger tube defective pipeline section of clipping; 4; adopt manual argon arc welding; polarity DCC-7, sealing weld silk 2 roads, not preheating; sealing weld silk interlayer temperature<50 ℃; 6~8 liters/minute of inwall argon gas (Ar) protections, 10~12 liters/minute of outside argon shields, electric current 30~70A; workpiece turns clockwise during welding; arc light is motionless, and 70~120 seconds/circle of weldering speed postwelding grinds off weld seam appearance bossing, check; 5; reinstall and two ends soldering and sealing; heat exchanger tube and new tubing butt joint reinstall tube sheet after be up to the standards, and the unnecessary pipeline section of undercut guarantees that heat exchanger tube stretches out 4~8 millimeters of lower perforated plates; adopt manual argon arc welding to carry out two ends soldering and sealing; sealing weld silk twice, not preheating, welding wire interlayer temperature<50 ℃; 6~8 liters/minute of inwall argon gas (Ar) protections; 10~12 liters/minute of outside argon gas (Ar) protections, electric current is 30~75A, 80~110 seconds/circle of weldering speed.
Butt joint groove α on above-mentioned new tubing and heat exchanger tube=30 °, welding effect is good.
When above-mentioned heat exchanger tube and new tubing butt welding, adopt the electric current of manual argon arc welding to can be 30-45A, weldering speed is 90~100 seconds/circle, the welding quality height.
The present invention compared with prior art has following advantage:
1, adopt processing method of the present invention, in a short time the defective heat exchanger tube is had big repair ability, reparation speed is fast, can repair more than 200, and prolong the service life of equipment greatly in every month.
2, since easily produce the epimere of stress corrosion and be subjected to the corrosion of first ammonium more serious on pipe end adopted the material-OOCr25Ni22Mo3 or the OOCr22Ni6Mo2 of erosion resistant more, corrosion resistance is strong, has improved the equipment decay resistance.
Describe embodiments of the invention in detail below in conjunction with accompanying drawing, but protection scope of the present invention is not limited only to the following examples:
Fig. 1 is pipe end processing schematic diagram
Fig. 2 is heat exchanger tube and new tubing butt joint groove manuscript 1
Fig. 3 is heat exchanger tube and new tubing butt joint groove manuscript 2
Processing method of the present invention is: at first mill heat exchanger tube two ends angle welding and tube head, reach requirement as Fig. 1, promptly on tube sheet 1, mill out the groove 2 of diameter phi=31~32mm, dark H1=1.8~2.3 millimeters, between groove 2 round bottoms and sidewall, mill out circular arc R=5 millimeter, tube sheet 1 tip to face distance heat exchanger tube 3 end face distance H2=100 millimeters, upwards extracting heat exchanger tube 3 epimeres then out, to make its end face be 700 millimeters from tube sheet 1 end face, clips 500 millimeters defectiveness pipeline sections of epimere; Be elected to be new tubing OOCr22MO6Ni3(and see Fig. 2) or OOCr25Ni22Mo2(see Fig. 3) to make its length be 680 millimeters, as shown in Figure 2, processes butt welding groove α at heat exchanger tube 3 and new 4 of tubing respectively 1=30 °, the S1=1.9-2.0 shown in Fig. 2, S2=1.6~2.0, the α among Fig. 3 2=30 °, S3=1.6, adopt manual argon arc welding, polarity DCC-7, fill out diameter and be 1.6 millimeters welding wire OOCr25Ni22Mn4Mo2N, twice, not preheating, welding wire interlayer temperature<50 ℃, 6~8 liters/minute of inwall Ar protections, 10~12 liters/minute of outside Ar protections, electric current is 35~45A, workpiece turns clockwise during welding, arc light is motionless, and weldering speed is 90~100 seconds/circle, and postwelding grinds off weld seam appearance bossing, butt weld is through x-ray inspection, dyeing inspection and macro-graph flawless, pore, slag inclusion, incomplete fusion, burning, turn over defectives such as slag, the bad phenomenon of unprotect, no indent, undercut; After the heat exchanger tube butt joint, reinstall tube sheet through being up to the standards, the unnecessary pipeline section of undercut keeps heat exchanger tube to stretch out 4~8 millimeters of lower perforated plates (preferably 6-7 millimeter).Adopt manual argon arc welding to carry out the soldering and sealing of heat exchanger tube two ends, filling out diameter is the welding wire OOCr25Ni22Mo2N. twice of 2 millimeters of φ, not preheating; welding wire interlayer temperature<50 ℃, inwall Ar6~8 liter/minute, 10~12 liters/minute of outside Ar protections; electric current 70~75A, 80~110 seconds/circle of weldering speed.

Claims (3)

1, changes the processing method of the local pipeline section of heat-exchanger tube of high pressure methylamine condenser, the steps include:
1). pipe end processing: mill heat exchanger tube two ends angle welding and tube head;
2). take out pipe: upwards extract the heat exchanger tube epimere out the heat exchanger tube epimere is partly exposed outside the tube sheet, clip heat exchanger tube epimere defectiveness pipeline section;
It is characterized in that described processing method has also adopted following steps:
3). select the processing of new tubing and heat exchanger tube butt joint groove: select new tubing OOCr22Ni6Mo3 or OOCr25Ni22Mo2 for use, make the length of new pipe length, process butt joint groove α=25~35 ° respectively at new tubing and heat exchanger tube joint greater than the heat exchanger tube defective pipeline section of clipping;
4). adopt manual argon arc welding, polarity DCC-7, sealing weld silk 2 roads, not preheating, welding wire interlayer temperature<50 ℃, 6~8 liters/minute of inwall argon gas (Ar) protections, 10~12 liters/minute of outside argon gas (Ar) protections, electric current 30~70A, workpiece turns clockwise during welding, and the welding gun arc light is motionless, 70~120 seconds/circle of weldering speed, postwelding grinds off soldered appearance bossing, check;
5). reinstall and two ends soldering and sealing: heat exchanger tube reinstalls tube sheet with new tubing welding after be up to the standards; the unnecessary pipeline section of undercut; guarantee that heat exchanger tube stretches out 4~8 millimeters of lower perforated plates, adopt manual argon arc welding to carry out two ends soldering and sealing, sealing weld silk twice; not preheating; welding wire interlayer temperature<50 ℃, 6~8 liters/minute of inwall argon gas (Ar) protections, 10~12 liters/minute of outside argon gas (Ar) protections; electric current is 30~75A, 80~110 seconds/circle of weldering speed.
2, the processing method of the local pipeline section of replacing heat-exchanger tube of high pressure methylamine condenser as claimed in claim 1 is characterized in that the butt joint groove α=30 ° on new tubing and heat exchanger tube.
3, the processing method of the local pipeline section of replacing heat-exchanger tube of high pressure methylamine condenser as claimed in claim 1 when it is characterized in that heat exchanger tube and new tubing butt welding, adopts the electric current of manual argon arc welding to can be 30~50A, and weldering speed is 90~100 seconds/circle.
CN 93115355 1993-01-08 1993-10-29 Processing method for replacing local pipe section of heat exchange pipe of high-pressure methylamine condenser Pending CN1089716A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN 93115355 CN1089716A (en) 1993-01-08 1993-10-29 Processing method for replacing local pipe section of heat exchange pipe of high-pressure methylamine condenser

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CN93110811.X 1993-01-08
CN93110811 1993-01-08
CN 93115355 CN1089716A (en) 1993-01-08 1993-10-29 Processing method for replacing local pipe section of heat exchange pipe of high-pressure methylamine condenser

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CN1089716A true CN1089716A (en) 1994-07-20

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CN 93115355 Pending CN1089716A (en) 1993-01-08 1993-10-29 Processing method for replacing local pipe section of heat exchange pipe of high-pressure methylamine condenser

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102817898A (en) * 2012-08-30 2012-12-12 广东明阳风电产业集团有限公司 Threaded hole and thread welding repair process
CN107068216A (en) * 2017-06-01 2017-08-18 哈电集团(秦皇岛)重型装备有限公司 HTGR heat exchanger tube weld seam X-ray detectoscope
CN112179199A (en) * 2020-10-14 2021-01-05 三门峡化工机械有限公司 Thin-wall stainless steel heat exchanger pipe head welding radiating pipe

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102817898A (en) * 2012-08-30 2012-12-12 广东明阳风电产业集团有限公司 Threaded hole and thread welding repair process
CN102817898B (en) * 2012-08-30 2015-11-11 广东明阳风电产业集团有限公司 A kind of screw thread welding repair technology
CN107068216A (en) * 2017-06-01 2017-08-18 哈电集团(秦皇岛)重型装备有限公司 HTGR heat exchanger tube weld seam X-ray detectoscope
CN112179199A (en) * 2020-10-14 2021-01-05 三门峡化工机械有限公司 Thin-wall stainless steel heat exchanger pipe head welding radiating pipe

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C06 Publication
PB01 Publication
C01 Deemed withdrawal of patent application (patent law 1993)
WD01 Invention patent application deemed withdrawn after publication