Naturally Occurring High-Chloride Coal and Superheater Corrosion—A Laboratory Study

Abstract

DOE Provided funds for C-E to investigate the fireside corrosion potential of commercial boiler tube alloys at elevated temperatures when exposed to the combustion products from a series of coals. The results of the laboratory and field tests were previously reported. In a supplementary phase of the program, C-E tested for the effect of chloride on similar alloys while firing a naturally occurring high chloride Midwestern bituminous coal in the same laboratory furnace. On the basis of exposure in the convection pass at temperatures from 1100–1700°F, Inconel Alloy 690 was found to have very good resistance to corrosion while Incoloy 800H and Tp-310 s. s. were good transitional materials. Poor materials were T-22, 316 s. s., Inconel 617, and Inconel 671.

Laboratory-simulated fuel-ash corrosion of superheater tubes in coal-fired ultra-supercritical-boilers

“…According to the literature, a Cr content in the alloy greater than about 25 mass% is necessary to achieve protection against coal-ash corrosion [1,5,9,13,16,17,19]. This should be the critical Cr content required in order to guarantee the formation of Cr 2 O 3 scales of high purity.…”

“…NIMONIC 263 at 700 8C is very sensitive to this type of attack, so its degradation is already extremely fast for 10% alkali sulphate and 30% does not increase the reaction Fig. [5] Plant exposure: 677 ± 727 8C, 1.7% S (coal), 6% alkali (ash); [13] [19] Betriebliche Auslagerung: 538 ± 871 8C, 0,6 ± 3,6% S, 0,4 ± 0,9% Na (Kohle) rate. Cross sections of ash-coated alloys (10% ash) exposed to 1% SO 2 , 700 8C, 2000 h: a) NIMO-NIC 263, b) NIMONIC 91; *ash; **corrosion layer; ***alloy Abb.…”

A new transient thermal fouling probe for cross flow tubular heat exchangers

“…Expressions (11) and (13) are then equivalent to a quadrupole presentation. So, the following matrix relationship between the Laplace-Fourier temperature-flux vectors can be written using this quadrupole formalism for a cylindrical layer r out À r in thick limited by two cylindrical surfaces of radii r = r in and r = r out :…”

“…Ever since the end of the 1970s, some gas-side fouling measuring devices have been envisaged [5,7,[10][11][12]14,17]. All of them provide physical information on fouling.…”

High‐temperature corrosion behavior of S30432 and TP310HCbN coatings in simulated 620°C ultra‐supercritical boiler coal ash/gas environment

“…The results indicated that the coal‐ash corrosion resistance increased with the increase in the chromium content in the alloy. [ 11–15 ] Some researchers examined numerous coal‐ash corrosion data and found that when the chromium content in the alloy was greater than 25%, its ability to resist the high‐temperature corrosion of coal ash was good. [ 16 ] In addition to laboratory research, field tests were conducted on various austenitic stainless steels in power plant boilers, confirming the importance of chromium in the alloy for achieving high‐temperature coal‐ash corrosion resistance.…”