Dissertation > Excellent graduate degree dissertation topics show

Phosphorus on the corrosion behavior of boiler materials , yellow phosphoric tail

Author: WuFei
Tutor: LongJinMing;ZuoHuaPing
School: Kunming University of Science and Technology
Course: Materials Science
Keywords: Yellow phosphoric tail gas boiler steel dew point corrosion stainless steel
CLC: TK228
Type: Master's thesis
Year: 2009
Downloads: 14
Quote: 0
Read: Download Dissertation

Abstract


The comprehensive utilization of yellow phosphoric tail gas is an important way of sustainable development in phosphoric industry. The economical way is to burn yellow phosphoric tail gas as boiler gas fuel because it contains CO 85%～95% in vol, however a difficult problem is the corrosion of boiler steels which results from yellow phosphoric tail gas. In this paper, firstly, the corrosion condition of boiler steels is studied by hanging sample corrosion tests and laboratory corrosion tests. The reasons and mechanism are studied, than some methods of avoiding corrosion and using schemes. The contents and conclusions of this paper are as follow:The corrosion properties of 316L,304 stainless steel and 20# boiler steel (20g) in a simulated corrosive atmosphere were investigated by means of accelerated corrosion test. The results show that in the simulated atmosphere the corrosion rate of 316L was significantly lower than that of 304 and 20g. At 250～300℃, the acid dew point corrosion became serious. Cavities were observed in the surface of 304 after the dew point corrosion, which means pitting corrosion was happened.The factors affecting the dew point temperature of yellow phosphoric tail gas were analyzed and discussed in respect of thermodynamics. The analysis indicated that the dewpoint temperature of the mixed system relied on the partial pressure of phosphoric acid vapor, water concentration in liquid phase and total pressure of the system and it had no direct relationwith the contents of NOx and COx in the flue gas. Their effect on the dewpoint temperature was shown by affecting the total pressure of the system.By using weight-loss method, macroscopical and microcosmic photograph of boiler steel, in this paper the author studys some factors that affect corrosion rate of boiler steel, and draws the influence law of the corrosion rate which is relate to temperature and phosph-oric acid concentration.Secondly, potentiodynamic polarization curve and EIS (Electroche-mical Impedance Spectroscopy) techniques were used to analyze the influence of different effect factors of corrosion on electrode reaction of boiler steel. EIS was applied to invest-igate the corrosion behavior of 304 stainless steel and 20g in the condition of different temperature and time. The results showed that, the corrosion resistance of the test material decreased with increasing of the temperature immersion time. Finally, this paper analyzed the corrosion step of the test material with inereasing of the soak period.

Related Dissertations

  1. Environmental Effects of Poisonous and Harmful Substances in the Typical Industrial Solid Wastes,X705
  2. Study on Corrosion Resistance and Condensation Property of Ni-P/Nano SiO2 Composite Coatings,TG174.4
  3. Study on the Dry Cutting Performance of Austenitic Stainless Steel 0Cr18Ni9,TG142.71
  4. Stainless steel fuel cell bipolar plate and its experimental and simulation,TM911.4
  5. 2205 hot workability and mechanical properties of stainless steel clad plate and Prediction,TG142.71
  6. Nuclear related materials mechanical properties and microstructure analysis,TL341
  7. 2205 duplex stainless steel plate TMCP technology research,TG335.5
  8. 7Cr14Mo dual vacuum stainless bearing steel organization and contact fatigue life,TG142.71
  9. Study on New Electrodeposition Processes of Aluminum Alloys and Stainless Steel,TQ153
  10. The Evaluation of the Biocompatibility of Nickel-free Austenitic Stainless Steel Using Annexin V/PI and Hoechst33342/PI Double Staining Method,R318.08
  11. Shandong LWGT’ Shot-rolled Annealing and Pickling Line Feasibility Study,F426.3
  12. Study on Texture and Microstructure of 436 and 432 FSS during Processling,TG142.71
  13. Research of Microalloying Nb and Ti in Ultra-purity 430 Ferritic Stainless Steel,TG142.71
  14. Low temperature high strength martensitic stainless steel composition, microstructure and properties of,TG142.71
  15. Study of Optimal Design for Waste Heat Boiler Steel Frame,TU391
  16. Study on the Characteristic of 304 Stainless Steel Hot Rolling Process,TG335.11
  17. Study on Drawing of Stainless Steel Bend,TG386
  18. Acid Corrosion Phenomenon Research on Wfgd in Power Plant,X701.3
  19. 316LN austenitic stainless steel stress corrosion cracking of welded joints,TG407
  20. 2205 Corrosion Research,TG142.71

CLC: > Industrial Technology > Energy and Power Engineering > Steam Power Engineering > Steam boiler > Repair, maintenance
© 2012 www.DissertationTopic.Net  Mobile