Shaning law law galaw ngut ai hpang, Cooling Tower ni hta Rusting hte Perforation byin wa ai lam ni

 

 

 

 

 

 

I. Core Corrosion Mechanism: Electrochemical n-gun gaw n-gun n-gun hte n-gun shayawm ai lam hpe uphkang nga ai

 

 

 

 

 

Hka lum ai nta ni a magri daw ni (law malawng gaw carbon steel hte galvanized steel) ni gaw hka-nbung lapran na makau grup yin hta aten galu hkam sha nga ai, dai shara hta npu kaw micro galvanic cell law law loi loi hte byin pru wa ai majaw, matut manoi electrochemical n-gun yawm wa ai lam byin pru wa ai – n-gun yawm wa ai lam a npawt nhpang rai nga ai.

 

Anode ginra na magri atom ni gaw oxidation reaction ni hpe hkrum nna, kalang lang magri ion (Fe → Fe2+ + 2e−) ni de garan mat wa ai majaw, magri matrix hpe matut manoi sum mat wa ai; hka hta rawng ai oxygen gaw electron ni hte pawng nna hydroxide ions (O2 + 2H2O + 4e− → 4OH−) hpe shabyin ya ai cathode ginra hta shayawm ai lam ni byin pru wa ai, dai gaw n-gun shayawm ai lam hpe matut manoi shabyin ya ai.

 

 

Dai n-gun shayawm ai lam kaw na pru wa ai n-gun dat [Fe(OH)2] gaw, n-gun dat [Fe(OH)3] de bai oxidized byin wa nna, hpang jahtum e, n-gun n-gun n-rawng ai hte n-gun n-rawng ai n-gun dat ni byin pru wa ai. Dense metal oxide film ni hte n bung ai sha, n-gun n rawng ai gaw makawp maga lam n lu jaw ai; de a malai, hka hte oxygen hpe hkap la nna, kata na magri n-gun hpe lawan ladan n-gun yawm shangun ai.

 

 

Grau nna hka hta chloride ions ni nga ai shaloi, shanhte gaw magri ntsa na passivation film de lawan ai hku shang nna, pat da ai cell ni hpe byin shangun ai majaw, buga ginra hta n-gun n rawng ai (local pitting corrosion) byin pru wa ai.

 

 

Pitting matut manoi sung wa ai hte maren, hpang jahtum e perforation byin pru wa ai, dai gaw cooling tower law law hta aten kadun-perforation byin wa na matu core trigger rai nga ai.

 

 

 

 

 

 

II. Lawan ai lam kaba mali: 3-5 ning laman lawan ai hku n-gun rawng ai lam hpe galaw lu na matu ahkyak ai lam ni

 

(1) Hka Hkrun Lam Hpe Hkrun Lam Hpe Hkrun Lam Hpe Hkrun Lam Hpe Hkrun Lam Hpe Hkrun Lam Hpe Hkrun Lam Hpe Grai Jat Jat Wa Ai

 

 

 

 

 

 

Hka shinggrup ai gaw, katsi ai nta npawt hpe n-gun shayawm ya ai "catalyst" zawn galaw ya ai. Hka a hkamja lam hkrat sum ai gaw, nlung n-gun hpe hkrak sha lawan shangun nna, ahkyak dik htum lawan shangun ai lam rai nga ai. Cooling tower galaw ai aten hta, matut manoi hka n-gun rawng ai majaw, hka hta chloride ions hte sulfate radicals zawn re ai ntsin ni law law lawm wa nna, hka n-gun hpe grai jat wa shangun nna, electrochemical corrosion rate hpe 3 kaw nna 5 lang jat wa shangun ai.

 

 

Dai aten hta, hka hkawm ai hka a pH manu hpe n hkang lu ai majaw, n-gun grau ja wa ai: pH 6.5 npu kaw rai yang, hka gaw acid byin nna, metal matrix hpe hkrak sha hka ja kau ya ai; pH 9 jan jang, scale loi loi hte byin pru wa ai. Scale gaw nlung ntsa hpe ka-up da ai majaw, under-deposit corrosion byin wa nna, buga na oxygen n-gun n bung ai lam ni hpe byin shangun nna, n-gun grau lawan shangun ai.

 

 

 

 

 

Dai hta n-ga, katsi ai nta ni a hka garan ai hte nbung garan ai ladat gaw hka hta rawng ai oxygen hpe (galaw madang 8–10 mg/L) hpring tup shangun nna, cathode reaction hpe matut manoi n-gun shaja ya nna, matut manoi byin nga ai n-gun hpe n-gun jaw ya ai. Hka kata na bacteria hte algae zawn re ai nli tum ni gaw biofilm ni hpe shabyin ya nna, shanhte a galai shai ai lam gaw hydrogen sulfide zawn re ai acidic dat ni hpe shapraw ya ai majaw, magri ntsa na passivation film hpe grau hkra machyi shangun nna, buga ginra hta n-gun grau ja wa shangun ai.

 

 

 

(2) Anti-Corrosion Coatings ni aten garai n du shi yang hkrat sum mat ai majaw, magri ni hpe makawp maga ya ai n-gun n nga mat ai

 

 

 

 

Cooling tower magri arung arai ni hta n-gun n rawng ai shingnip ni gaw, n-gun n rawng ai hpe ninghkap ai shawng nnan na makawp maga lam hku nna magam gun nga ai. Shawng nnan coating hkrat sum ai majaw, magri ni hpe n-gun ja ai makau grup yin de hkrak sha shapraw ya ai majaw, lawan ladan n-gun yawm mat chye ai.

 

Coating hkrat sum ai lam gaw madung hku nna lam masum kaw na pru wa ai: langai, gawgap ai lam hta n kaja ai lam ni – jung ai shaloi, cooling tower law law hta n hkum tsup ai magri ntsa derusting (Sa2.5 standard hpe n lu hkan sa ai) nga ai, dai majaw coating hte magri matrices lapran n kaja ai hku n-gun n rawng ai, dai hpang n-gun n rawng ai hte n-gun n rawng ai; lahkawng, grup yin hpe hkra machyi shangun ai – ultraviolet radiation, shani shagu na nbung katsi ai lam galai shai ai, hka lwi ai hpe hka lim ai hte hpaw da ai-nbung grup yin hta ga nhpu ni htum mat ai majaw, shanhte a makawp maga lam hpe n mai lang mat ai;

 

 

masum, structural gaps – coatings ni hpe welds, flanges hte component joints ni hta maren mara n mai bang ai, dai shara ni hta hka hte nhprang wan ni shinggyin hpawng nga ai, n-gun n rawng ai "tsin-yam tsindam shara" ni byin wa nna, n-gun n rawng ai shara ni byin wa nna, n-gun n rawng ai shara ni byin wa ai.

 

 

 

(3) Arung arai lata ai lam hte hkrang shapraw ai lam hta n-gun kya ai lam ni gaw, n-gun yawm mat ai

 

 

N kaja ai arung arai lata ai lam gaw, katsi ai nta ni hta aten kadun-rusting byin wa na matu, npawt nhpang lam kaba langai rai nga ai. Manu jahpu hpe shayawm na matu, galaw shapraw ai ni law law gaw, n-gun n rawng ai n-gun n rawng ai, grau nna, grai lawan ai n-gun rawng ai -hka (sh) acidic hka law ai shara ni hta, n-gun n rawng ai, n-gun rawng ai carbon steel (sh) galvanized steel hpe lang ma ai.

 

N law htum galvanized layer a n-gun hte n kaja ai galvanizing galaw ai lam ni a majaw, galvanized layer ni lawan ai hku htum mat nna, n-gun yawm mat ai majaw, makawp maga ai atsam hpe sum mat ai. Dai aten hta, n tara ai cooling tower structural design, ga shadawn, component joint ni hta grai law ai gap hkat ai lam ni hte hka lim ai lam n kaja ai majaw, aten galu-hka shinggyin la lu ai hte buga ginra hta n hkru n kaja ai makau grup yin ni hpe byin shangun ai. Tower a nbung laru maga de n kaja ai hku galaw ai majaw, nbung n-gun n rawng ai majaw, hka n-gun gaw magri ni hpe lawan ladan htu shangun nna, n-gun grau sawng wa ai.

 

 

 

(4) N kaja ai hku galaw ai hte gram lajang ai lam gaw, n-gun grau sawng shangun ai

 

 

 

Masha law law gaw, shani shagu na cooling tower ni hpe galaw ai lam hte gram lajang ai lam hpe n yu n hkan galaw ai majaw, n-gun n rawng ai lam ni hpe n mu lu ai sha, n hkang lu ai majaw, hpang jahtum e, lawan ladan rawt jat wa nna, n-gun rawng ai lam ni byin wa ai.

 

Masha law malawng gram lajang ai lam hta n-gun kya ai lam ni gaw: hka hkawm ai hka a hkamja lam hpe ayan n jep yu ai sha, aten dep n-gun shayawm ai tsi ni hte n-gun shayawm ai tsi ni hpe n bang ai majaw, hka a hkamja lam hpe n-gun n rawng hkra hkra machyi shangun ai;

 

nta kata na scale, biofilms hte debris ni hpe ayan n san seng hkra galaw ai majaw, buga ginra hta n-gun grau ja wa ai; anti-corrosion coatings ni hpe ayan n jep yu nna, n-gun n rawng ai hte n-gun n rawng ai hpe aten dep n gram lajang ai majaw, magri ni hpe matut manoi dan dawng shangun ai;

 

katsi majan aten hta antifreeze ladat n nga ai, katsi majan-thaw cycles a majaw magri daw ni hta n-gun yawm mat nna, n-gun yawm mat na matu n-gun yawm mat ai shara ni byin wa ai.

 

 

 

III. Daw dan lam

 

 

Shaning law law galaw ngut ai hpang, katsi ai nta ni hta n-gun n rawng ai hte n-gun n rawng ai lam ni gaw, lam langai a majaw n re, electrochemical corrosion hpe core hku nna kayau kaya galaw ai majaw, hka a hkam kaja lam hkra machyi ai, coating hkrat sum ai, arung arai hte npawt nhpang n kaja ai, n hkrak ai hku galaw ai lam ni hte rau, aten galu-supposition galaw ai majaw byin pru wa ai re.

 

 

Cooling tower ni a service life hpe galu kaba hkra galaw na matu, shakut shaja ai lam ni hpe source kaw nna hpang ra ai: grai n-gun ja ai n-gun n rawng ai arung arai ni hpe lata la ra ai, n-gun n rawng ai coating hpe madang masat da ra ai, hka lim ai hka a hkam kaja lam hpe hkang zing ai lam hpe n-gun ja hkra galaw ra ai, shani shagu galaw ai lam hte gram lajang ai lam ni hpe jep joi ai lam ni hpe galaw ra ai. Ndai hku galaw yang she, n-gun yawm mat ai lam hpe atsawm sha shayawm lu nna, aten garai n du yang n-gun yawm mat ai hte n-gun yawm mat ai hpe koi lu na re.