Technical Manual - Section 3 (Safety Hazards)

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for exposure to hydrogen sulfide and benzene should a leak or release occur. Small emissions of carbon monoxide and hydrogen sulfide may occur during regeneration of catalyst. Safe work practices and/or appropriate personal protective equipment may be needed for exposures to chemicals and other hazards such as noise and heat; during testing, inspecting, maintenance and turnaround activities; and when handling regenerated or spent catalyst. Table III:2-13 CATALYTIC REFORMING PROCESS Feedstocks From Process Typical products...................... To Desulfurized naphtha Coker Rearrange, High octane gasoline................Blending Naphthene-rich Hydrocracker dehydrogenate Aromatics.................................Petrochemical fractions Hydrodesulfur Hydrogen.................................Recycle, hydrotreat, etc. Straight-run naphtha Atmospheric Gas...........................................Gas plant fractionator Figure III:2-16 Platforming Process III:2-32
CATALYTIC HYDROTREATING Catalytic hydrotreating is a hydrogenation process used to remove about 90% of contaminants such as nitrogen, sulfur, oxygen, and metals from liquid petroleum fractions. These contaminants, if not removed from the petroleum fractions as they travel through the refinery processing units, can have detrimental effects on the equipment, the catalysts, and the quality of the finished product. Typically, hydrotreating is done prior to processes such as catalytic reforming so that the catalyst is not contaminated by untreated feedstock. Hydrotreating is also used prior to catalytic cracking to reduce sulfur and improve product yields, and to upgrade middle-distillate petroleum fractions into finished kerosene, diesel fuel, and heating fuel oils. In addition, hydrotreating converts olefins and aromatics to saturated compounds. CATALYTIC HYDRODESULFURIZATION PROCESS Hydrotreating for sulfur removal is called hydrodesulfur-ization. In a typical catalytic hydrodesulfurization unit, the feedstock is deaerated and mixed with hydrogen, preheated in a fired heater (600-800º F) and then charged under pressure (up to 1,000 psi) through a fixed-bed catalytic reactor. In the reactor, the sulfur and nitrogen compounds in the feedstock are converted into H2S and NH3. The reaction products leave the reactor and after cooling to a low temperature enter a liquid/gas separator. The hydrogen-rich gas from the high-pressure separation is recycled to combine with the feedstock, and the low-pressure gas stream rich in H2S is sent to a gas treating unit where H2S is removed. The clean gas is then suitable as fuel for the refinery furnaces. The liquid stream is the product from hydrotreating and is normally sent to a stripping column for removal of H2S and other undesirable components. In cases where steam is used for stripping, the product is sent to a vacuum drier for removal of water. Hydrodesulfurized products are blended or used as catalytic reforming feedstock. OTHER HYDROTREATING PROCESSES Hydrotreating processes differ depending upon the feedstocks available and catalysts used. Hydrotreating can be used to improve the burning characteristics of distillates such as kerosene. Hydrotreatment of a kerosene fraction can convert aromatics into naphthenes, which are cleaner-burning compounds. Lube-oil hydrotreating uses catalytic treatment of the oil with hydrogen to improve product quality. The objectives in mild lube hydrotreating include saturation of olefins and improvements in color, odor, and acid nature of the oil. Mild lube hydrotreating also may be used following solvent processing. Operating temperatures are usually below 600º F and operating pressures below 800 psi. Severe lube hydrotreating, at temperatures in the 600-750º F range and hydrogen pressures up to 3,000 psi, is capable of saturating aromatic rings, along with sulfur and nitrogen removal, to impart specific properties not achieved at mild conditions. Hydrotreating also can be employed to improve the quality of pyrolysis gasoline (pygas), a by-product from the manufacture of ethylene. Traditionally, the outlet for pygas has been motor gasoline blending, a suitable route in view of its high octane number. However, only small portions can be blended untreated owing to the unacceptable odor, color, and gum-forming tendencies of this material. The quality of pygas, which is high in diolefin content, can be satisfactorily improved by hydro-treating, whereby conversion of diolefins into mono-olefins provides an acceptable product for motor gas blending. HEALTH AND SAFETY CONSIDERATIONS Fire Prevention and Protection The potential exists for fire in the event of a leak or release of product or hydrogen gas. III:2-33
Page 1 and 2: OR-OSHA TECHNICAL MANUAL OR-OSHA TE
Page 3 and 4: SECTION III: CHAPTER 1 OIL WELL DER
Page 5 and 6: C. STABILITY CONSIDERATIONS FOUNDAT
Page 7 and 8: D. OBSERVATIONS, DIRECTIONS, AND CO
Page 9 and 10: SECTION III: CHAPTER 2 PETROLEUM RE
Page 11 and 12: Year Process name Purpose By-produc
Page 13 and 14: Crude oils are also defined in term
Page 15 and 16: (dicycloparaffins) found in the hea
Page 17 and 18: and boilers can leave deposits of v
Page 19 and 20: C. PETROLEUM REFINING OPERATIONS IN
Page 21 and 22: Table III:2-3 OVERVIEW OF PETROLEUM
Page 23 and 24: D. DESCRIPTION OF PETROLEUM REFININ
Page 25 and 26: CRUDE OIL DISTILLATION (FRACTIONATI
Page 27 and 28: Even though these are closed proces
Page 29 and 30: The solvent is separated from the p
Page 31 and 32: Table III:2-9 VISBREAKING PROCESS F
Page 33 and 34: HEALTH AND SAFETY CONSIDERATIONS Fi
Page 35 and 36: Figure III:2-14 Fluid Catalytic Cra
Page 37 and 38: HYDROCRACKING Hydrocracking is a tw
Page 39: egeneration and changeover. Catalys
Page 43 and 44: chemicals and other hazards such as
Page 45 and 46: needed to prevent HCl from entering
Page 47 and 48: ALKYLATION Alkylation combines low-
Page 49 and 50: HEALTH AND SAFETY CONSIDERATIONS Fi
Page 51 and 52: Figure III:2-23 Molecular Sieve Dry
Page 53 and 54: SATURATE GAS PLANTS Saturate gas pl
Page 55 and 56: Table III:2-21. STEAM REFORMING PRO
Page 57 and 58: Safety Control of treater temperatu
Page 59 and 60: minerals and dissolved impurities t
Page 61 and 62: phenols, ammonia, sulfides, and oth
Page 63 and 64: GAS AND AIR COMPRESSORS Both recipr
Page 65 and 66: Safety Depending on the product and
Page 67 and 68: APPENDIX III:2-1. GLOSSARY ABSORPTI
Page 69 and 70: DEWAXING The removal of wax from pe
Page 71 and 72: interaction of sulfur compounds in
Page 73 and 74: SECTION III: CHAPTER 3 PRESSURE VES
Page 75 and 76: Figure III:3-1. Some Major Parts of
Page 77 and 78: spherical with wall thickness in th
Page 79 and 80: LIQUID PENETRANT TEST (PT) This met
Page 81 and 82: D. INFORMATION FOR SAFETY ASSESSMEN
Page 83 and 84: @ Other design code vessels -- Maxi
Page 85 and 86: SECTION III: CHAPTER 4 INDUSTRIAL R
Page 87 and 88: Regulator Coordinate Robot Cylindri
Page 89 and 90: Figure III:4-2. Industrial Robots:
Page 91 and 92:
DEGREES OF FREEDOM Regardless of th
Page 93 and 94:
OTHER ACCIDENTS Other accidents can
Page 95 and 96:
SAFEGUARDING DEVICES Personnel shou
Page 97 and 98:
F. BIBLIOGRAPHY American National S
Page 99 and 100:
Enabling Device A manually operated
Page 101 and 102:
Start-up, Initial Initial drive pow
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Technical Manual - Section 3 (Safety Hazards)

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