Technical Manual - Section 3 (Safety Hazards)

Safety
Control of treater temperature is important as phenol can
cause corrosion above 400º F. Batch and in-line blending
operations require strict controls to maintain desired product
quality. Spills should be cleaned and leaks repaired to avoid
slips and falls. Additives in drums and bags need to be
handled properly to avoid strain. Wax can clog sewer or oil
drainage systems and interfere with wastewater treatment.
Health
When blending, sampling, and compounding, personal
protection from steam, dusts, mists, vapors, metallic salts, and
other additives is appropriate. Skin contact with any
formulated grease or lubricant should be avoided. Safe work
practices and/or appropriate personal protection may be
needed for exposures to chemicals and other hazards such as
noise and heat; during inspection, maintenance, and
turnaround activities; and while sampling and handling
hydrocarbons and chemicals during the production of
lubricating oil and wax.
E. OTHER REFINERY OPERATIONS
HEAT EXCHANGERS, COOLERS, AND
PROCESS HEATERS
HEATING OPERATIONS
Process heaters and heat exchangers preheat feedstocks in
distillation towers and in refinery processes to reaction
temperatures. Heat exchangers use either steam or hot
hydrocarbon transferred from some other section of the
process for heat input. The heaters are usually designed for
specific process operations, and most are of cylindrical
vertical or box-type designs. The major portion of heat
provided to process units comes from fired heaters fueled by
refinery or natural gas, distillate, and residual oils. Fired
heaters are found on crude and reformer preheaters, coker
heaters, and large-column reboilers.
COOLING OPERATIONS
Heat also may be removed from some processes by air and
water exchangers, fin fans, gas and liquid coolers, and
overhead condensers, or by transferring heat to other systems.
The basic mechanical vapor-compression refrigeration
system, which may serve one or more process units, includes
an evaporator, compressor, condenser, controls, and piping.
Common coolants
are water, alcohol/water mixtures, or various glycol solutions.
HEALTH AND SAFETY CONSIDERATIONS
Fire Protection and Prevention
A means of providing adequate draft or steam purging is
required to reduce the chance of explosions when lighting
fires in heater furnaces. Specific start-up and emergency
procedures are required for each type of unit. If fire impinges
on fin fans, failure could occur due to overheating. If
flammable product escapes from a heat exchanger or cooler
due to a leak, fire could occur.
Safety
Care must be taken to ensure that all pressure is removed
from heater tubes before removing header or fitting plugs.
Consideration should be given to providing for pressure relief
in heat-exchanger piping systems in the event they are
blocked off while full of liquid. If controls fail, variations of
temperature and pressure could occur on either side of the
heat exchanger. If heat exchanger tubes fail and process
pressure is greater than heater pressure, product could enter
the heater with downstream consequences. If the process
pressure is less than heater
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