2-darajali titaniumli isitgich trubkasini izolyatsiya qiluvchi natriy titanat shkalasi hosil bo'lishining oldini olish uchun 90 gradusda 25% natriy gidroksid eritmasida maksimal ruxsat etilgan kremniy kontsentratsiyasi (ppm) qanday?

Silica (SiO2) interacts with titanium in 25% sodium hydroxide at 90°C to create sodium titanate (Na2TiO3) and sodium silicate scale. These scales have a relatively low thermal conductivity (0.5–1.5 W/m·K). Silica The maximum concentration of silica allowed to prevent the formation of insulating scale is 50 ppm. A scale thickness of >0.1 mm in 500 hours at >50 ppm ishlab chiqariladi, bu esa issiqlik uzatishni sezilarli darajada yo'qotishiga olib keladi.

Silikat konsentratsiyasi va miqdoriy shkala shakllanishi

25% NaOH da 500 soat davomida 90 daraja:

Silika (ppm) Shkala qalinligi (mkm) Shkala tarkibi Issiqlik o'tkazuvchanligini kamaytirish (%)
0 0 Yoʻq 0 10 5–15 Natriy silikat 2–5 25 15–40 Aralashtirilgan silikat/titanat 5–15 50 40–80 Natriy titanat ustunlik qiladi 15–30 100 80–150 Qalin titanat 30–50 250 150–300 shkalada silsiladan 000 sm gacha. bag'rikenglik

Harorat (daraja) uchun Maks silika<0.1 mm Scale (ppm)Recommended Max (ppm) Silica Control Guide 70 100 75 80 75 50 90 50 30 100 30 20

Oʻlchangan kremniy dioksidi (ppm) Tavsiya etilgan harakat Kutilayotgan masshtab qalinligi (mikron/yil)
<20 No <20
20–50 Monitor Monthly 20-80 50-100Dilute or filter solution 80-150 >100 Replace solution >150
Muhandislik uchun tavsiya

90 daraja haroratda 25% NaOH uchun silika konsentratsiyasi 30 ppm dan past bo'lishi kerak. Kremniy bilan ifloslanishini oldini olish uchun suyultirish uchun deionizatsiyalangan suvdan foydalaning. Muhandis izolyatsion natriy titanat shkalasi paydo bo'lishiga yo'l qo'ymaslik uchun kremniyni boshqaradi.