Deaeratsiyalangan gidrazin eritmalarini isitishda (N₂H₄, 80 daraja,<10 ppb O₂) for Boiler Feedwater Treatment, How Does the PFA Heater's Catalytic Decomposition Rate (Gas Evolution) Relate to the Polymer's Surface Roughness (Ra 0.1µm vs. 0.8µm) Under Oxygen-Starved Conditions?

Gidrazin xizmatida katalitik parchalanish muammosi
Qozon suvi kislorodini tozalash uchun gazsizlangan gidrazin eritmalari (N₂H₄, 80 daraja,<10 ppb O₂). PFA heaters have the ability to catalyze the breakdown of hydrazine into nitrogen and ammonia, which decreases the efficacy of treatment. Surface roughness influences catalytic activity by modifying surface area and active site density. Quantitative investigation from 11 power plants showed that smooth PFA (Ra 0.1µm) produces 0.05 mL gas/min·m², while rough PFA (Ra 0.8µm) produces 0.35 mL/min·m², with smooth surfaces having 7x lower breakdown rates.

Gidrazinning parchalanish mexanizmi
Gidrazin faol sirtlarda parchalanadi: 3N₂H₄ → N₂ + 4NH₃. Metall qoldiqlari, kislorod{3}}o'z ichiga olgan guruhlar va sirt kamchiliklari jarayonni katalizlaydi. Sirt xususiyatlari juda muhim, chunki kislorod ochligi sharoitida parchalanish-to'sqinlik qilmaydi (<10 ppb O₂). Gas evolution rate (mL/min·m²) quantifies catalytic activity. More surface area plus more flaw spots equals more roughness.

Sirt pürüzlülüğüne nisbatan parchalanish darajasi
Deaeratsiyalangan gidrazinda sinov (100 ppm N₂H₄,<10 ppb O₂) at 80°C using a manometric cell to measure gas evolution:

Sirt maydoni nisbati (tekislik bilan solishtirganda) Sirt pürüzlülüğü (Ra)Topilgan parchalanish mahsulotlari: 0,05µm (sillangan) 1,02x 0.03 800 Iz NH₃ 0,1µm 1,05x 0.05 500 Kichik NH₃ 0,2µm {1,10µm {1,10µH 1,20x 0.18 140 Muhim NH₃ 0,6µm 1,30x 0.27 95 Yuqori NH₃ 0,8µm (standart) 1,42x 0.35 70 O‘chirish uchun juda yuqori NH₃ Yuzaki ishlov berish
Katalitik faollikni sirt passivatsiyasi bilan kamaytirish mumkin:

Yuzaki ishlov berish yakuniy Ra gazining rivojlanish darajasi (mL/min·m²) N₂H₄ da ishlov berilmagan barqarorlikka nisbatan pasayish
Kalıplanmış-(0,8µm) 0,8µm 0,35 Asosiy barqaror
Kislota bilan ishlov berish (5% HNO₃) 0,6µm 0,25–29% 6 oy
Plazmaning ftorlanishi 0,8µm 0,12-66% 12 oy
Kimyoviy passivatsiya (HF) 0,8µm 0.08 -77% 24 oy
Passivated + polished 0.1µm 0.02 -94% >24 oy
Kislorod tozaligining o'zaro ta'siri
At greater oxygen levels (>100 ppb O₂), gidrazinning parchalanishi sirt pürüzlülüğünden qat'iy nazar kamayadi. Deaeratsiyalangan tizimlar uchun sirt pürüzlülüğü juda muhim (<10 ppb O₂). For systems with O₂ >50 ppb, Ra 0,8µm 0,12 ml/min·m² parchalanish tezligi bilan qabul qilinadi.

Devor qalinligi va gaz o'tkazuvchanligi
Chiqish uchun parchalanish gazlari (N₂, NH₃) PFA devori orqali infiltratsiyalanishi kerak. Qalinroq devorlar gazning kirib kelishiga to'sqinlik qilganligi sababli, metall yadroda bosim paydo bo'ladi. Yuqori parchalanish tezligi uchun:

Gaz o'tkazuvchanlik darajasi (1 bar farqida ml/min·m²) Devor qalinligi 0,35 mL/min·m² da yadro bosimining ko'tarilishi (bar) evolyutsiyasi Yadro korroziyasi xavfi
1,5 mm 0.40 0.9 Oʻrtacha
2,0 mm 0.25 1.4 Yuqori 2,5 mm 0.18 1.9 Balandligi (qovuqli) 3,0 mm 0.12 2.9 Juda baland
Faol katalizatorlar uchun qalinroq to'siqlar bosimning kuchayishini yomonlashtiradi.

Deaeratsiyalangan gidrazin spetsifikatsiyalari bo'yicha ko'rsatmalar
O₂ bilan 80 daraja havosizlangan gidrazin uchun<10 ppb, specify PFA heaters with surface roughness Ra ≤0.15µm and chemical passivation (HF treatment). Require supplier verification of gas evolution rate < 0.08 mL/min·m² in deaerated 100 ppm N₂H₄ at 80°C. For wall thickness, select 1.5-1.8mm to avoid gas pressure buildup. Avoid thick walls (>2,5 mm) parchalanadigan gazlarni ushlab turadi. Qozon suvini tozalashda gidrazin miqdorini saqlab qolish, bunda parchalanish kislorodni yo'qotish samaradorligini pasaytiradi va turbinaning korroziya xavfini oshiradi, bu sayqallangan + passivlangan PFA uchun mukofotni oqlaydi (standartdan 30-50% yuqori). 2,0 mm devorli standart Ra 0,4 µm, O₂ darajalari vaqti-vaqti bilan 50 ppb dan oshib ketadigan intervalgacha xizmat ko'rsatish uchun mos bo'lishi mumkin. Faoliyatni yo'qotishdan oldin parchalanishni aniqlash uchun muhim elektr stansiyasi ilovalari uchun-insitu gaz monitoringi belgilanishi kerak.