By: Allen Zeyher
Since the U.S. Environmental Protection Agency at the end of
last May removed hot-mix asphalt plants from its list of industries considered
major sources of hazardous air pollutants, you might think it would get easier
to get a permit for a new plant. You would be wrong, according to Steve Malloy,
sales manager for AESCO/Madsen, Auburn, Wash.
"You can meet every federal, state and local regulation
and it still won't go through," Malloy told Roads & Bridges.
"It's getting harder and harder."
One of the biggest obstacles to siting a new hot-mix asphalt
(HMA) plant is the associated truck traffic, which the public perceives as an
annoyance and a hazard to neighborhood children. The other obstacle is the
lingering public perception of asphalt plants as pollution generators, even
though the reality is very different.
"The plants can meet whatever air quality codes happen
to be out there," Malloy said, even with the many varied emission
standards set by local authorities based on local ambient air pollutant levels.
In fact, the filtering systems, or baghouses, on modern
asphalt plants are so efficient that they need fewer filter units, or bags.
AESCO/Madsen has redesigned its baghouse models to be smaller and contain
fewer, improved bags.
Despite the permitting difficulties, Malloy said,
AESCO/Madsen's sales in 2002 were actually an improvement over 2001.
Asphalt Drum Mixers Inc. (ADM) also had a good year in 2002:
"Our segment of the market is going strong," Jon Patti, a salesman
for ADM, told Roads & Bridges. "We have not had a lack of work."
As for the removal of HMA plants from contention as a major
polluter, Patti said, "It doesn't necessarily put your neighbor at ease.
It just means that the federal government no longer [considers] them a
hazardous polluter. It doesn't even mean that on a state level they've changed
the way they're doing things."
CEI Enterprises Inc. traditionally just built heating,
storage and mixing equipment, but a couple of years ago the company created the
Nomad portable HMA plant for the international market. It was designed to be a
smaller, simpler complement to the plants produced by the Albuquerque, N.M.,
company's parent company, Astec.
CEI announced recently that it would start selling the Nomad
plant in the U.S. The plant employs traditional technology and simple controls
and has no recycling capability.
Ben Brock, vice president and general manager of CEI, is
optimistic about Nomad's foray into the domestic asphalt plant market. "We
just started building these in 2000," he told Roads & Bridges,
"and we're over 20 plants already, which we feel pretty good about."
Products
What follows are brief descriptions of a few of the
asphalt-production product announcements we have received recently. It is not
meant to be a comprehensive survey of products currently on the market.
HMA unbound
The Nomad plant from CEI can produce up to 130 tph of hot
mix and comes in four units: a mixer, a drag conveyor and hopper, a tank and a control
house (Circle 915). The mixer unit includes a combination dryer and mixer,
aggregate bins, an aggregate feed system, a burner, a drum, an exhaust fan and
a dust collection system. The units are trailer-mounted for easy transport to a
jobsite, and the plant can be set up without a crane. A front-end loader is all
that is needed.
Drumming up the miles
The Milemaker line of portable and stationary counter-flow
asphalt plants from ADM, Huntertown, Ind., produce from 160 to 425 tph,
including SHRPS and Superpave, and process up to 40% RAP (Circle 916).
To go with the drum mixers, ADM also makes self-erect silos.
The SES Series (Circle 917) uses a gasoline engine to power a hydraulic pump
system to move the silo and drag-slat conveyor from the horizontal
transportation position to the vertical operating position within 15 minutes.
The three models--SES30, SES50 and SES75--have storage
capacities of 30, 50 and 75 tons, respectively.
All on one trailer
DM Series drum-mix asphalt plants from AESCO/Madsen can be
furnished with a standard venturi wet scrubber or optional baghouse pollution
control system mounted on the same frame as the drum mix dryer (Circle 918).
The optional baghouse is a pulse-jet design. All bags and cages can be accessed
from the top for easy repair and maintenance.
The DM Series is an entire plant on a trailer, standard with
one or two feed bins, manual controls, a surge system and the wet scrubber. The
drums come in three sizes ranging in production from 40 to 160 tph. The drums
are driven by four machined and heattreated trunnions.
Happy birthday
Astec Industries Inc. celebrated its 30th anniversary in
2002. The Chattanooga, Tenn., company was founded by a group of people who
wanted to make better hot-mix asphalt plants and was named to reflect the
founders' interest in asphalt technology.
Astec's Flametec group introduced a new burner this year.
Called Whisper Jet, the burner emits extremely low levels of nitrogen oxide and
carbon monoxide. It employs an efficient oil atomizer that uses compressed air
for finer spray and better combustion (Circle 919).
Under consolidation
CMI and Cedarapids were consolidated in 2002 under the
umbrella of Terex Corp.
CMI Terex continues to make the Triple-Drum counter-flow
plant (Circle 921). It combines three distinct drying and heating zones in a
single drum, resulting in higher production capacities for virgin and
high-ratio RAP mixes.
Trunnion drive is now standard equipment on all CMI drum
mixers.
Dynamic duo
The Duo Drum CF from ALmix USA, Fort Wayne, Ind., is
available either as a skid-mounted or as a highly portable unit (Circle 922).
Capacities range from 60 to 500 tph. The unit has a full-size, fuel-efficient
dryer, a mixing section suitable for both coating and heat transfer to RAP and
convertibility from drum to batch.
