Caustic soda(NaOH) ndi imodzi mwazinthu zofunika kwambiri zopangira chakudya chamankhwala, zomwe zimapangidwa pachaka za 106t. NaOH imagwiritsidwa ntchito mu organic chemistry, popanga aluminiyamu, m'makampani opanga mapepala, m'makampani opanga zakudya, kupanga zotsukira, etc. Caustic soda ndi co-product popanga chlorine, 97% yomwe imatenga. malo ndi electrolysis wa sodium kolorayidi.
Soda wa Caustic amakhudza kwambiri zinthu zazitsulo zambiri, makamaka pa kutentha kwambiri komanso ndende. Zakhala zikudziwika kwa nthawi yayitali, komabe, kuti nickel ikuwonetsa kukana kwa dzimbiri kwa caustic soda nthawi zonse ndi kutentha, monga Chithunzi 1 chikuwonetsa. Kuonjezera apo, kupatula pa kutentha kwambiri ndi kutentha kwambiri, faifi tambala ilibe chitetezo ku caustic-induced stress-corrosion cracking. The faifi tambala muyezo aloyi 200 (EN 2.4066/UNS N02200) ndi aloyi 201 (EN 2.4068/UNS N02201) Choncho ntchito pa magawo a caustic soda kupanga, amene amafuna kukana dzimbiri. Ma cathodes omwe ali mu cell electrolysis yomwe amagwiritsidwa ntchito mu nembanemba amapangidwanso ndi mapepala a faifi tambala. Magawo akunsi kwa mtsinje woikamo mowa amapangidwanso ndi faifi tambala. Amagwira ntchito motsatira mfundo za ma evaporator amitundu yambiri makamaka ndi ma evaporator akugwa. Mu mayunitsi faifi tambala ntchito mu mawonekedwe a machubu kapena chubu mapepala kwa chisanadze evaporation exchangers kutentha, monga mapepala kapena atavala mbale kwa mayunitsi chisanadze evaporation, ndi mipope zonyamulira caustic koloko njira. Malinga ndi otaya mlingo, ndi caustic koloko makhiristo (supersaturated njira) zingachititse kukokoloka pa kutentha exchanger machubu, zomwe zimapangitsa m'malo mwawo pambuyo ntchito nthawi 2-5 zaka. Njira ya evaporator ya filimu yomwe ikugwa imagwiritsidwa ntchito popanga soda yokhazikika kwambiri, ya anhydrous caustic. Munjira yakugwa yopangidwa ndi Bertrams, mchere wosungunuka pa kutentha pafupifupi 400 ° C umagwiritsidwa ntchito ngati sing'anga yotenthetsera. Apa machubu opangidwa ndi otsika mpweya faifi tambala aloyi 201 (EN 2.4068/UNS N02201) ayenera kugwiritsidwa ntchito chifukwa pa kutentha kuposa 315 °C (600 °F) apamwamba mpweya zili mu muyezo faifi tambala kalasi aloyi 200 (EN 2.4066/UNS N02200) ) kungayambitse kugwa kwa graphite pamalire a tirigu.
Nickel ndi chinthu chomwe chimakondedwa kwambiri pomangira ma evaporator a caustic soda pomwe zitsulo za austenitic sizingagwiritsidwe ntchito. Pamaso pa zonyansa monga klorate kapena mankhwala a sulfure - kapena pamene mphamvu zapamwamba zimafunika - zipangizo zokhala ndi chromium monga alloy 600 L (EN 2.4817 / UNS N06600) zimagwiritsidwa ntchito nthawi zina. Chochititsa chidwi kwambiri ndi madera a caustic ndi chromium yapamwamba yokhala ndi aloyi 33 (EN 1.4591/UNS R20033). Ngati zinthuzi zikugwiritsidwa ntchito, ziyenera kuwonetseredwa kuti zogwirira ntchito sizingabweretse kupsinjika-kusweka kwa dzimbiri.
Aloyi 33 (EN 1.4591/UNS R20033) imawonetsa kukana kwa dzimbiri mu 25 ndi 50% NaOH mpaka powira komanso mu 70% NaOH pa 170 °C. Aloyiyi idawonetsanso ntchito yabwino kwambiri pakuyesa m'munda mu chomera chomwe chimakhudzidwa ndi koloko kuchokera ku diaphragm.39 Chithunzi 21 chikuwonetsa zotsatira za kuchuluka kwa mowa wa diaphragm caustic, womwe udayipitsidwa ndi kloridi ndi klorate. Kufikira 45% NaOH, alloy 33 (EN 1.4591 / UNS R20033) ndi nickel alloy 201 (EN 2.4068 / UNS N2201) amawonetsa kukana kofananira. Ndi kuwonjezeka kutentha ndi ndende aloyi 33 amakhala ngakhale kugonjetsedwa ndi faifi tambala. Chifukwa chake, chifukwa cha aloyi yake yayikulu ya chromium 33 ikuwoneka kuti ndi yothandiza kuthana ndi mayankho a caustic ndi ma chloride ndi hypochlorite kuchokera ku diaphragm kapena mercury cell process.
Nthawi yotumiza: Dec-21-2022