Page 600 - Materials Chemistry, Second Edition

CAT3525_C19.qxd 1/28/2005 5:05 PM Page 571
Management of Used Oil 571
Additional
treatment
options
Centrifuge

Used oil Collection Blended with
and storage virgin
Coarse Settling Fine filtration products or
filtration or centrifuge
other used
oils
Hazardous vs.
nonhazardous Chemical
waste determination addition
Air, water
emissions;
sludge from
Waste tank bottoms
disposal

FIGURE 19.4 A used oil processing schematic (U.S. EPA, 1994).

19.8.5 OFF-VS. ON-SPECIFICATION USED OIL
Under the Used Oil Management Standards, if used oil exceeds any of the allowable levels of the
constituents and properties levels listed in Table 19.4, it is designated “off-specification used oil,”
and there are restrictions as to its use including burning for energy recovery. In the table, limits are
provided regarding concentrations of certain metals, flash point, and total halogens. Used oil that
does not exceed any of these values may be burned for energy recovery and any fuel produced from
used oil by processing, blending, or other treatment, is not subject to regulation. If it complies with
all specifications, it is deemed “on-specification used oil.”
Off-specification used oil may be burned for energy recovery in the following:

● Industrial furnaces
● Industrial boilers (such as asphalt plants and cement kilns), located on the site of a facil-
ity engaged in manufacturing processes
● Utility boilers used to produce electric power, steam, heated, or cooled air
● Hazardous waste incinerators subject to 40 CFR Parts 264 or 265
● Used oil-fired space heaters provided that (a) the used oil is generated on the facility site
or is received from household DIY used oil generators; (b) the heater is designed to have
a maximum capacity of 0.5 million Btu/h or less; and (c) the combustion gases are vented
outside (U.S. EPA, 1992)
The used oil must be generated on-site or collected from DIYs.
Off-specification used oil is effectively burned in the above systems because their operating
temperatures are much higher than space heaters and other small heaters. The heat generated causes
the used oil and its organic contaminants to be combusted almost completely, thus reducing the
quantity of atmospheric contaminants released. In addition, large burners are usually equipped with
pollution control equipment that further reduces emissions (Nolan et al., 1990).
Burners of off-specification used oil are required to obtain an EPA identification number.
Facilities must demonstrate that the used oil will be burned in a suitable device; for example, their
combustors must possess equipment that adequately reduces atmospheric emissions. Storage spec-
ifications are the same as those for transporters, and burners are required to follow the same proce-
dures to treat releases to the environment (Booz et al., 1999).