Technical Manual - Section 3 (Safety Hazards)

More documents

Recommendations

Info

eboilers, exchangers, and other locations where acid may settle out. Health Because this is a closed system, exposures are expected to be minimal under normal operating conditions. There is a potential for exposure to caustic wash (sodium hydroxide), to phosphoric acid used in the process or washed out during turnarounds, and to catalyst dust. Safe work practices and/or appropriate personal protective equipment may be needed for exposures to chemicals and other hazards such as noise and heat, and during process sampling, inspection, maintenance, and turnaround activities. Figure III:2-20 Polymerization Process III:2-38
ALKYLATION Alkylation combines low-molecular-weight olefins (primarily a mixture of propylene and butylene) with isobutene in the presence of a catalyst, either sulfuric acid or hydrofluoric acid. The product is called alkylate and is composed of a mixture of high-octane, branched-chain paraffinic hydrocarbons. Alkylate is a premium blending stock because it has exceptional antiknock properties and is clean burning. The octane number of the alkylate depends mainly upon the kind of olefins used and upon operating conditions. SULFURIC ACID ALKYLATION PROCESS In cascade type sulfuric acid (H2SO4) alkylation units, the feedstock (propylene, butylene, amylene, and fresh isobutane) enters the reactor and contacts the concentrated sulfuric acid catalyst (in concentrations of 85% to 95% for good operation and to minimize corrosion). The reactor is divided into zones, with olefins fed through distributors to each zone, and the sulfuric acid and isobutanes flowing over baffles from zone to zone. The reactor effluent is separated into hydrocarbon and acid phases in a settler, and the acid is returned to the reactor. The hydrocarbon phase is hot-water washed with caustic for pH control before being successively depropanized, deisobutanized, and debutanized. The alkylate obtained from the deisobutanizer can then go directly to motor-fuel blending or be rerun to produce aviation-grade blending stock. The isobutane is recycled to the feed. HYDROFLUORIC ACID ALKYLATION PROCESS Phillips and UOP are the two common types of hydro-fluoric acid alkylation processes in use. In the Phillips process, olefin and isobutane feedstock are dried and fed to a combination reactor/settler system. Upon leaving the reaction zone, the reactor effluent flows to a settler (separating vessel) where the acid separates from the hydrocarbons. The acid layer at the bottom of the separating vessel is recycled. The top layer of hydrocarbons (hydrocarbon phase), consisting of propane, normal butane, alkylate, and excess (recycle) isobutane, is charged to the main fractionator, the bottom product of which is motor alkylate. The main fractionator overhead, consisting mainly of propane, isobutane, and HF, goes to a depropanizer. Propane with trace amount of HF goes to an HF stripper for HF removal and is then catalytically defluorinated, treated, and sent to storage. Isobutane is withdrawn from the main fractionator and recycled to the reactor/settler, and alkylate from the bottom of the main fractionator is sent to product blending. The UOP process uses two reactors with separate settlers. Half of the dried feedstock is charged to the first reactor, along with recycle and makeup isobutane. The reactor effluent then goes to its settler, where the acid is recycled and the hydrocarbon charged to the second reactor. The other half of the feedstock also goes to the second reactor, with the settler acid being recycled and the hydrocarbons charged to the main fractionator. Subsequent processing is similar to the Phillips process. Overhead from the main fractionator goes to a depropanizer. Isobutane is recycled to the reaction zone and alkylate is sent to product blending. Table II:2-17 ALKYLATION PROCESS Feedstocks From Process Typical products............... To Petroleum gas Distillation or cracking Unification High octane gasoline..........Blending Olefins Cat. or hydro cracking n-Butane & propane...........Stripper or blender Isobutane Isomerization III:2-39
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 and 40: egeneration and changeover. Catalys
Page 41 and 42: CATALYTIC HYDROTREATING Catalytic h
Page 43 and 44: chemicals and other hazards such as
Page 45: needed to prevent HCl from entering
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
show all

Technical Manual - Section 3 (Safety Hazards)

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?