Corrosion and stress corrosion cracking in coal liquefaction systems
Based on the observations reported in this abstract and described previously, we feel the fractionation column corrosion problem can be explained in the following way. The severe corrosion observed in pilot plant fractionation columns is due to the presence of chlorine in the feed coal for the liquefaction process. The chlorine in the coal is principally in the form of inorganic chlorides with lesser amounts of oxychlorides, adsorbed chlorine, and organic chlorine compounds making up the balance. These chlorine compounds are converted to HCl in the preheater and dissolver areas of the plants. The HCl is neutralized by amines in the coal liquids to form amine hydrochlorides, which are transported in the coal liquids to the fractionation columns. The amine hydrochlorides are concentrated in the fractionation columns by a reflux action involving thermal dissociation at higher temperatures and association (and condensation) to reform the amine hydrochlorides at lower temperatures. Corrosive fluids are formed when HCl liberated by thermal dissociation of the amine hydrochlorides dissolves in coal liquids and interacts with acidic components of these liquids to form strong acid solutions.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6695022
- Report Number(s):
- CONF-821145-1; ON: DE83003433
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
36 MATERIALS SCIENCE
360105 -- Metals & Alloys-- Corrosion & Erosion
AMINES
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
COAL LIQUEFACTION
COAL LIQUEFACTION PLANTS
CORROSION
CORROSIVE EFFECTS
FUNCTIONAL MODELS
HALIDES
HALOGEN COMPOUNDS
INDUSTRIAL PLANTS
LIQUEFACTION
MATERIALS TESTING
ORGANIC COMPOUNDS
PILOT PLANTS
STRESS CORROSION
SULFIDATION
TESTING
THERMOCHEMICAL PROCESSES