Ammonium bisulfide corrosion corrosion engineering eng. A small fraction of the sulfur dioxide is oxidized to sulfur trioxide over the scr catalyst. Ammonium bisulfide corrosion, on the other hand, occours at high velocity locations air cooler headers, pipe bends and leads to general thinning like erosion. Material corrosion resistance guide fluid technology. Evaluation of corrosion in different parts of an oil refinery using. Ammonium bisulfide corrosion in hydrotreating units. Thermodynamic derivations of various ammonium salt. Ammonium bisulfite is not compatible with copper, zinc or their. Ammonium bisulfide nh4hs corrosion is an aggressive form of localized corrosion commonly found in hydroprocessing units throughout the reactor effluent air cooler reac and associated piping. Pdf prediction and assessment of ammonium bisulfide corrosion. Pdf prediction of ammonium bisulfide corrosion and. The addition of hydrogen sulfide h2s increases the acidic activity, and thus.
If the feed or makeup gas to the hydroprocessing unit is contaminated with chlorides, ammonium chloride nh4cl salt deposition can also occur. However, in march 2000 a joint industry program jip titled prediction and assessment of ammonium bisulfide corrosion under refinery sour water service conditions was initiated to develop a quantitative engineering database and provide guidelines to predict corrosion in hydrogen sulfide h 2 sdominated alkaline sour water systems. The electrochemical work included the measurements of the potential of separate alloys as well as the measurements of galvanic potential. The ammonium bisulfide causes accelerated corrosion and maintenance problems for given metallurgy in the refinery depending on concentrations. In addition, side reactions may produce the undesirable byproducts ammonium sulfate nh 4 2 so 4 and ammonium bisulfate nh 4 hso 4, which can cause plugging and corrosion of downstream equipment. Therefore, they reduced the water rate, which increased the ammonium bisulfide to about 8. Corrosion corrosion in piping systems caused by thermodynamic and electrochemical processes corrosion problems and methods of protection and prevention. A study of galvanic corrosion in stagnant ammonium bisulfide solution h.
Bisulfide undergoes the typical chemical reactions of a thiolate. The released sulfur reacts to form hydrogen sulfide h2s and mercaptans together with traces of ammonia and hydrogen cyanides. Acids will cause the release of sulfur dioxide, a severe respiratory irritant. How to differentiate ammonium chloride from ammonium. Formation of nh4hs salts can lead to reactor effluent air cooler reac tube plugging, and if wet, can lead to rapid underdeposit corrosion. Ammonium bisulfide corrosion of reactor effluent air coolers reac and stripper overhead is a reliability issue for the refining industry. This paper summarizes results of phase ii of a joint industry program jip that addressed ammonium bisulfide nh4hs corrosion. It is the salt derived from the ammonium cation and the hydrosulfide anion. Jul 18, 2017 part 8 ammoniumbisulfide corrosion sandeep academy.
Usually, these salts are ammonium chloride nh 4 cl or ammonium bisulfide nh 4 hs. Contamination in amine systems september 2010 4 other contaminants that could accelerate corrosion include. These saltslead to fouling of piping and heat exchangers resulting in loss of duty, underdeposit corrosionwhen wetted, and corrosive sour water solutionsonce sufficient water is available to dissociate these salts into solution. Metals and corrosion resistance engineering toolbox. Fiberglass coatings aluminum stainless 304 stainless 316 carbon steel monel neoprene teflon viton interplastics 8441 hetron fr992 dow 510a epoxy 250 f inorganic zinc 150 f coal tar epoxy 300 f plasite 7122l har, tfe. Chemical resistance guide c hemical r hayward flow control. The impacts of several process variables on corrosion were quantified. This type of corrosion has already resulted in major equipment failures, fires and explosions. Reseacharticle a study of galvanic corrosion in stagnant ammonium bisulfide solution h. The electrochemical work included the measurements of the potential of separate alloys as well as the measurements of galvanic.
Best way to have an indication if nh4hs corrosion is likely is to analyze the sour water of the cold seperator vessel for its ammonia content. Ammonium chloride n f f n f g g g 210s 210 210 g n g g. Us7585677b2 method of evaluating corrosion resistance of. Kept basic with naoh, as acid will release hydrogen sulfide gas. A study of galvanic corrosion in stagnant ammonium bisulfide. Prediction of ammonium bisulfide corrosion and validation with. On earth the compound is encountered mainly as a solution, not as the solid, but nh 4 sh ice is believed to be a substantial component of the cloud decks of the gasgiant planets jupiter and saturn, with sulfur produced by its photolysis. Ammonium bisulfide has similar destructive effect like ammonium chloride, but ammonium chloride corrosion is not much easy to be predicted due to higher limit. The corrosion probes showed a rate of 6 to 11 mpy, which they consider unacceptably high due to the potential severity of this type of corrosion. Control valves control valve terminology, bodies, trim, flow characteristics, cv and kv sizing, noise, actuators and positioners.
Pdf prediction and assessment of ammonium bisulfide. Method of evaluating corrosion resistance of material under. Scientific opinion on flavouring group evaluation 49, revision 1 fge. The presence of chlorides or salt formation can lead to damage or production losses in oil refineries. According to the test method, when evaluating the corrosion resistance of a material under an ammonium bisulfide environment, the corrosion resistance of the material is evaluated by simulating the relationship between the ammonium bisulfide concentration of a test solution and the pressure in advance, and then determining the ammonium. This waste acid is either treated with ammonia for conversion to fertilizer grade ammonium sulfate, or is burned in an acid recovery plant for conversion to sulfuric acid for recycling. The salt exists as colourless, watersoluble, micaceous crystals. Wet acid gas corrosion of the overhead system is accelerated if hcn is also present. The information is based primarily on the immersion.
Prediction and assessment of ammonium bisulfide corrosion. Conformer generation is disallowed since mixture or salt. Ammonium bisulfite is colorless crystals which are soluble in water. Organic sulfur and nitrogen compounds are converted to hydrogen sulfide and ammonia in hydrotreater reactors. Used in photography, textiles, synthetic flavors, coloring brasses, bronzes, and iron control.
Galvanic corrosion of carbon steel cs coupled to four different alloys, namely, 316 ss, 321 ss, incoloy 825, and 2205 ss, was studied in. The attached references from refincor summarize descriptions, locations of damage, corrosion rates and rules of thumb for corrosion by alkaline sour water reported by other refiners in more than 50 years of documenting nace t8 refining committee. A method of evaluating the corrosion resistance of a material in an ammonium bisulfide environment, which comprises the steps of. This corrosion has been the cause of several major fires, explosions, and costly unscheduled shutdowns 7, 8. Prediction of ammonium bisulfide corrosion and validation. An overview of ammonium chloride nh4cl corrosion in the.
Ammonium bisulfide nh4hs, abs corrosion is a well known problem in the petroleum refining industry. Ammonium bisulfide corrosion can cause corrosion in the unit itself, as well as the inlet and outlet piping. Prediction of ammonium bisulfide corrosion and validation with refinery plant experience article pdf available in nace international corrosion conference series january 2006 with 348 reads. Corrosion rates as high as 200 mpy have been observed in aggressive ammonium bisulfide solutions. The product of these two gases can form a salt, ammonium bisulfide nh4hs as the reactor effluent stream cools. The cs mostly suffers from general corrosion and erosion. Extra strength is built into all hartzell fiberglass fans by the use of. Water is injected to prevent accumulation of the salt, which results in a corrosive abs solution that causes different kinds of corrosion.
Prediction of ammonium bisulfide corrosion and validation with refinery plant experience michael s. Sour corrosion failures in hydrocracker reactor effluent air cooler. A continuous supply of wash water is typically injected upstream of the reactor effluent air cooler to reduce corrosion and fouling in the cooler. Corrosion resistance of different materials compound iron and steel cast iron ni resist 300 series stainless monel inconel incoloy copper lead aluminum nickel copper chloride f x f c a x copper cyanide a copper plating a copper sulphate x c a a a c a x creosote a a a a a a deoxidine a deoxylyle a diphenyl 300350 a di sodium phosphate 25%. Titanium has gained acceptance in many media where its corrosion resistance and engineering properties have provided the corrosion and design engineer with a reliable and economic material. Phase ii extended the initial research work in phase i of the program, commonly referred to as the. When strongly heated, bisulfide salts decompose to produce sulfide salts and hydrogen sulfide. Corrosion never takes vacation health and safety issues and lpo ammoniaamine salts are major contributors to refining unit overhead corrosion modeling the crude unit overhead system can improve overall unit performance and reliability troubleshooting tool unit monitoring oli stream analyzer has enabled us to model potential for salt. Horvath1 2 consultant 19003 white candle drive spring, tx 77388 sridhar srinivasan 1 honeywell international, inc. Journal of geology and geoscience a study of galvanic corrosion. Upon treatment with a standard acid, it converts to hydrogen sulfide and metal salt. This phase of the program was focused on nh3dominated sour waters typically found in refinery services such as the overhead systems of some sour water stripper units.
Ammonium bisulfide a a a ammonium carbonate a a a a a a a a c ab ab ab ab b a ammonium casenite a. Corrosion rates ar iel epenin upon concentration, temperature an the presence o trace elements in the process liui. The increased denitrification did not materialize, and they had 5. Ammonium chloride corrosion in the refining industry. The corrosion data in this section is mainly based on the results of general corrosion laboratory tests, which are not strictly comparable with actual service conditions. Summarizes results from phase iii of the joint industry program jip on refinery alkaline sour water ammonium bisulfide corrosion. Corrosion resistance chart aluminum brass bronze hastelloy, c276 malleable iron carbon steel monel stainless steel,304 stainless steel,316 nylon polypropylene seal material acetate solvents crude 1 x x 1 2 2 1 1 a x t acetate solvents pure 1 1 1 1 x 1 1 1 a x t acetic acid 80% 3 x x 1 x 1 1 1 x x tevnb. A study of galvanic corrosion in stagnant ammonium.
It also generates a large volume of acidic ammonium bisulfate nh 4 hso 4, typically as much as 2. As a byproduct of the selective catalytic reduction scr systems for nitrogen oxide nox emissions control, abs could result in unit efficiency deterioration, even unit outage. Giesbrecht flint hills resources, lp po box 64596 st paul, minnesota 55164 richard j. Galvanic corrosion of carbon steel cs coupled to four different alloys, namely, 316 ss, 321 ss, incoloy 825, and 2205 ss, was studied in deaerated 3. C by electrochemical techniques under stagnant condition. Prediction and assessment of ammonium bisulfide corrosion under. Strong oxidizers such as nitrates, nitrites or chlorates. What is the reaction chemistry behind the formation of. Ammonia and three ammonium salts from chemical group 30 view page or view pdf. As the effluent cools, an ammonium bisulfide nh 4 hs salt forms in the sour water from reaction of the hydrogen sulfide and ammonia as follows.
Alkaline materials will accelerate the evolution of ammonia. This happens when sulfur and nitrogen in the feed get converted to ammonia nh3 and hydrogen sulfide h2s which react to form nh4hs. Ammonium bisulfide nh4hs is a clear, yellowish liquid that contains a high concentration of h2s and is wellknown to cause corrosion problem in associated. Ammonium bisulfide nh 4 hs corrosion is a wellknown problem in hydrotreater and hydrocracker effluent air cooler reac areas. This paper summarizes results of a joint industry program jip to address ammonium bisulfide nh 4 hs corrosion in h 2 sdominated alkaline sour waters typically found in refinery services such as the reactor effluent air cooler reac systems of hydroprocessing units. A study of the prediction of ammonium bisulfate formation. Prediction and assessment of ammonium bisulfide corrosion under refinery sour water service conditionspart 2 richard j.
Ammonium bisulphate an overview sciencedirect topics. Ammonia and three ammonium salts from chemical group 30 view page or view pdf scientific opinion on flavouring group evaluation 49, revision 1 fge. Method of evaluating corrosion resistance of material. Ammonium chloride corrosion may be genernal or localized corrosion, often pitting, normally occuring under ammonium chloride or amine salt deposits, often in the absence of a free water phase. Refincor ammonium bisulfide references the hendrix group. It is a strong irritant to skin and mucous membranes. Ammonium salts represent a common problem for the refining industry. Ammonium bisulfide corrosion corrosion engineering engtips. The subject of alkaline sour water corrosion in petroleum refineries over the past 25 years has been addressed in the literature. Pdf this paper summarizes results of a joint industry program jip to address ammonium bisulfide nh 4hs corrosion in h 2sdominated alkaline sour. Ammonium chloride corrosion has affected equipment and piping in areas such as.
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