Nonhydrocarbons

(https://www.osha.gov/dts/osta/otm/otm_iv/otm_iv_2.html)

a. Sulfur Compounds. Sulfur may be present in crude oil as hydrogen sulfide, as compounds (e.g. mercaptans, sulfides, disulfides) or as elemental sulfur. Each crude oil has different amounts and types of sulfur compounds, but as a rule the proportion, stability, and complexity of the compounds are greater in heavier crude-oil fractions. Hydrogen sulfide is a primary contributor to corrosion in refinery processing units. Other corrosive substances are elemental sulfur and mercaptans. Moreover, the corrosive sulfur compounds have an obnoxious odor.

Pyrophoric iron sulfide results from the corrosive action of sulfur compounds on the iron and steel used in refinery process equipment, piping, and tank s. The combustion of petroleum products containing sulfur compounds produces undesirables such as sulfuric acid and sulfur dioxide. Catalytic hydrotreating process es such as hydrodesulfurization remove sulfur compounds from refinery product streams. Sweetening processes either remove the obnoxious sulfur compounds or convert them to odorless disulfide s, as in the case of mercaptans.

b. Oxygen Compounds. Oxygen compound s such as phenol s, ketones, and carboxylic acid s occur in crude oils in varying amounts.

c. Nitrogen Compounds. Nitrogen is found in lighter fractions of crude oil as basic compounds, and more often in heavier fractions of crude oil as non-basic compounds that may also include trace metals such as copper, vanadium, and/or nickel. Nitrogen oxides can form in process furnaces. The decomposition of nitrogen compounds in catalytic cracking and hydrocracking processes forms ammonia and cyanide s that can cause corrosion.

d. Trace Metals. Metals, including nickel, iron, and vanadium are often found in crude oils in small quantities and are removed during the refining process. Burning heavy fuel oils in refinery furnaces and boilers can leave deposits of vanadium oxide and nickel oxide in furnace boxes, ducts, and tubes. It is also desirable to remove trace amounts of arsenic, vanadium, and nickel prior to pr o cessing as they can poison certain catalysts.

e. Salts. Crude oils often contain inorganic salts such as sodium chloride, magnesium chloride, and calcium chloride in suspension or dissolved in entrained water (brine). These salts must be removed or neutralized before pr o cessing to prevent catalyst poisoning, equipment corrosion, and fouling. Salt corrosion is caused by the hydrolysis of some metal chlorides to hydrogen chloride (HCl) and the subsequent formation of hydrochloric acid when crude is heated. Hydrogen chloride may also combine with ammonia to form ammonium chloride (NH4Cl), which causes fouling and corrosion.

Слова для сдачи наизусть:

1. h y drogen s u lfide - сероводород
2. elem e ntal s u lfur - свободная сера в нефтепродуктах
3. stability - устойчивость
4. compl e xity - множество составляющих; многокомпонентность
5. refinery processing - химическая переработка нефти; крекинг
6. obn o xious o dor - неприятный запах
7. pyrophoric iron - пирофорное железо; пирофорность – способность твёрдого

материала в мелкораздробленном состоянии к

самовоспламенению на воздухе при отсутствии нагрева

1. undes i rables - нежелательные вещества / соединения
2. sulfuric acid - серная кислота
3. sulfur dioxide - двуокись серы
4. hydrotreating process - процесс гидроочистки (≈ sweetening process)
5. hydrodesulfurization - гидрообессеривание
6. o dorless disulfide - двусернистое соединение без запаха
7. o xygen c o mpound - кислородное соединение
8. ph e nol - карболовая кислота; бесцветные игольчатые кристаллы
9. k e tones - летучие жидкости или легкоплавкие твёрдые вещества
10. carbox y lic acid - карбоновая кислота
11. trace metals - металл, содержащийся в ничтожных количествах; сверхредкий металл
12. cyanide [ ] - соль цианистоводородной кислоты
13. a rsenic - мышьяк
14. sodium chl o ride [ ] - хлорид натрия; каменная соль
15. magnesium chloride - хлорид магния
16. in suspension - во взвешенном состоянии
17. entrained water (brine) - скопившаяся вода; соляной раствор
18. hydrogen chloride - хлороводород
19. hydrochloric acid - соляная кислота

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