Elementis Specialties, a leading maker of specialty paint additives, has installed a zeolite-based air pollution control (APC) system in its plant.

When chemist Fred Daniel launched his Jersey City, NJ-based colorants and additives business in 1957, paint manufacturing was still more art than science. The advances in chemistry, physics and engineering behind today’s materials, processes, production equipment and substrates still lay in the future. But Daniel’s 20-plus years in the coatings industry had convinced him that simply reducing the particle size of pigments and other additives — ideally, to something approaching their ultimate fineness — could make for dramatic improvement in color intensity, hiding power, weather resistance, and other qualities of most coatings products.

He was right. Over the years, Daniel, a hands-on chemist of the “old school,” developed an array of grinding and blending technologies and equipment, most of them modified to meet the needs and requirements of his specially trained workforce, and all aimed at making a better product. By 1996, when the company was acquired for $30 million by London-based Harrisons & Crosfield, Daniel Products had operations in 80 countries and enjoyed an enviable reputation as a reliable supplier of some 450 specialty products to improve the performance of paint, ink, sealants, adhesives, and floor products and related materials. Their product line included pigment dispersions, anti-foaming agents, metal chelators and other proprietary drying compounds, organo-clay thickeners, UV light stabilizers, and other additives such as micronized waxes and silica dispersions.

In 1997 Harrisons & Crosfield, fast becoming a leading international specialty chemicals group, was renamed Elementis plc. The following year it acquired Hightstown, NJ-based Rheox, the leading producer of organoclay rheological additives, and merged it with the former Daniel firm to form Elementis Specialties Inc. The Jersey City facility continued essentially as before, using mainly natural materials in small-batch, often custom-blended operations and relying on the skills of its 100-plus employees rather than sophisticated QA systems to maintain its high quality standards. “We’ve got some unique, multi-function products with unique qualities, and folks here are very, very proud of that,” says Elementis Regulatory Affairs Manager Jay Greene.

Growing in a Crowded Neighborhood

With customer demand growing, Elementis began planning in 1997 for a major capacity expansion at its Jersey City plant, situated in a mixed inner-city residential and light industrial neighborhood. Physical expansion was not possible, since the 110,000-square-foot facility already fills the allowable space on its roughly 3/4-block site. The alternative was to intensify production, by extending business hours and introducing additional workshifts. This strategy avoided the permitting and other issues that would have been triggered by a plant expansion, but the increased production schedule raised important air-quality issues, since the existing air pollution control (APC) equipment was not designed to handle the larger volumes of in-plant air.

Like urban industrial facilities everywhere, Elementis faces close scrutiny from neighbors, as well as from federal, state, and local regulatory agencies. “With a residential neighborhood on one side, and a new New Jersey Transit intermodal terminal on the other,” says Greene “we put a very high priority on continually monitoring and improving our control of any potential air emissions.” With future air discharge volumes projected at hundreds of thousands of cubic feet daily, Greene began studying alternatives for expanding or replacing the company’s air quality control capabilities. “Our challenge was to increase production without increasing the number of tons of pollutants discharged, and even, if possible, reducing the quantity of potential pollutants emitted by the plant.”

Elementis’ existing system used a carbon adsorption unit driven by a 150-hp rooftop fan. Ambient air from the production floor traveled by way of two bag houses to a ground-level stainless steel tank. There, the HAPs and VOCs were captured in a 22,500-lb bed of activated carbon granules, and the clean air discharged to the atmosphere. The air permit for the system allowed for a maximum nine hours per day operation (2,214 hours per year) at 10,000–12,000 cubic feet per minute (CFM) air discharge. Contaminated carbon was trucked offsite for flame regeneration. As a result of the planned production growth and the resultant increase in air emissions, the loading on the carbon bedwould have increased to the point that the carbon bed would be changed 18 times, each change requiring between eight and 12 hours’ downtime and costing approximately $25,000.

Longer production hours would sharply increase APC costs. The production schedule for the year 2000 alone would require 26 carbon bed changes, adding roughly $650,000 to air quality costs and increasing Elementis’ reportable hazardous waste by an additional 585,000 lbs, since environmental rules require the VOC-contaminated carbon to be manifested as hazardous waste — and these numbers were expected to increase substantially in forward years.

The carbon system had other drawbacks as well, Greene says, the most important being the need to shut down production during carbon bed changes. “Vacuuming the carbon dust and particulates out of the bed is a noisy, dirty operation, and at future production levels we would be doing it once a week. That was not only excessively cost-intensive from a financial standpoint, but we would also be losing one day’s production every five to 10 days.”

To find a better APC technology, Greene selected BEM Systems Inc., a multidisciplinary environmental and hazardous-waste consulting firm based in Chatham, NJ. BEM also provided engineering, construction management and permitting services for the new APC system. “We chose BEM Systems partly for their excellent technical capabilities, but equally because we knew they could provide a turnkey solution, from planning through procurement, installation, and startup,” Greene noted. “Our own engineering department is fully occupied with production-related work, so we very much needed an external, turnkey process. And beyond that, we decided to go for a system that, from the technology standpoint, would be state-of-the-art, not merely the best available.”

BEM Senior Chemical Engineer Brian Pedersen, P.E., was project manager. “We talked with a large number of APC equipment vendors,” Pedersen says, “and looked at several widely used types of carbon adsorbers and thermal oxidizers. After reviewing proposals from six vendors, we concluded that a fixed-bed zeolite concentrator system was the best choice to meet Elementis’ criteria. As we kept reworking the numbers, it was clear that maintenance costs for a carbon adsorption system would have been prohibitively high at their projected future production levels, while a zeolite concentrator system could handle the large air volumes more economically, and also deal with a broader spectrum of airbornes.”

Molecular Sieves

Zeolites, a class of naturally occurring microporous aluminosilicate minerals that can act as a kind of “molecular sieve,” have been used since the late 1940s to improve various types of industrial processes. Today’s synthetic zeolites are precisely engineered materials with great purity and stability, and highly selective adsorption properties. They are used widely as catalysts in the natural gas and petrochemical industries, and in the manufacture of products ranging from refrigerants and glass to cat litter, air fresheners, and laundry detergents.

“In air pollution control applications, zeolites perform much like activated carbon,” Pedersen said, “but because they are engineered ceramic products, with very uniform pore size, they have several advantages. They provide greater selectivity and control. Being hydrophobic, they are not affected by water or humidity, so they can adsorb more VOCs. And they can withstand higher regeneration temperatures than carbon.”

For Elementis, BEM specified Re-Gensorb™, a patented zeolite concentrator developed and manufactured by M&W Industries, Rural Hall, NC, one of a few companies developing zeolite-based APC technologies. Specifically designed for applications with large air volumes and low concentrations of VOCs, Re-Gensorb is a multiple-fixed-bed system that uses MOLSIV® high-silica Zeolite, an engineered product from UOP LLC (Des Plaines, IL), to adsorb VOCs and HAPs from the airstream.

Two variable-speed 150-hp, 30,000 cfm-capacity fans force VOC and particulate-laden air from the plant floor through a pulse-jet bag house and a filter house, and then into the concentrator system, comprising eight beds of zeolite. The clean air is discharged directly to the stack. Fresh hot air is back-flushed through the VOC-laden zeolite bed and cleaned by being passed through the system’s flame oxidizer before being injected into the stack for discharge.

Within the Re-Gensorb unit, each cell is sequentially taken offline for regeneration, so one bed is in regeneration at all times. A stream of warm air releases the adsorbed contaminants, and the resulting low-volume, high-concentration airstream is passed through a small flame oxidizer where the VOCs and HAPs are converted to harmless CO2 and water vapor, with negligible quantities of NOx. After regeneration, the fresh adsorber cell is returned online to adsorb in tandem with several other cells, and the next cell is segregated for regeneration.

The Re-Gensorb system is still an emerging technology, although the zeolite itself is a well-known, durable product with a good track record. Nevertheless, BEM had enough confidence in the technology to provide Elementis with an almost unheard-of warranty: a five-year performance guarantee including 100% coverage of potential replacement costs.

The system is rated at up to 30,000 CFM, roughly a 600% increase in emissions-handling capacity, but it has roughly the same total footprint as the old. It is also quieter, and its greater efficiency allowed the engineers to use a thermal oxidizer only about 1/20 the size of a standard unit—with the added benefit that the plant engineers can take off heat from the flame regeneration system for use elsewhere in the facility, for an additional energy saving.

A computer-based programmable logic controller system, together with an independent real-time continuous emissions sampling and monitoring system, creates and maintains a continuously updated database and archive for management and regulatory purposes. “This is one of the things I insisted on early on because I wanted to prove where we were,” Greene said. “Record-keeping in the environmental business is what you live or die on; without good records the entire enterprise can be put at risk, even if your compliance program is 100% effective.”

The zeolite system also eliminates a minor but real fire hazard associated with carbon-based APC systems. Since these systems work by adsorbing HAPs and VOCs onto activated carbon granules, there is a finite risk that certain ambient chemicals, including ketones and others used in paint manufacturing, may react with the carbon to cause spontaneous combustion in the carbon bed unless airflow in the system is maintained continuously. “We are not concerned about a serious fire,” Greene said, “since we have an excellent fire-suppression system. But even a small fire would trigger the flushing system, and that could easily ruin a week’s production — not to mention dumping 20,000 gallons of contaminated carbon around the place. With the zeolite concentrator, that’s just another issue we don’t have to worry about.”

"State-of-the-Art is Really Where You Have to be"

In its first full year of operation, the zeolite system has more than satisfied Elementis’ criteria, Greene says. “Our projected cost increase with the carbon APC system was $650,000 plus at least 18 scheduled carbon bed changes and a major increase in the amount of reportable hazardous waste,” he said. “The new technology is performing as expected, and our latest internal audit shows that it is on track to produce an average annual savings of $422,000.”

Greene kept the old carbon bed system running while the new one was being put in place; tie-ins were carried out during normal downtimes (e.g., changing the old carbon system out). He later elected to keep the old carbon bed system as a backup, with appropriate upgrades, making it easier to maintain production in case of downtime on the new system. The deteriorating bag houses have been removed, and current plans are to use the old carbon bed system to capture particulates and VOCs during its use as the backup system. “This saves the cost of replacing the bag houses,” he says, “while allowing the plant to operate for about 50 additional hours per month under this backup system.”

Although the new system officially went online February 20, 1999, it is still (as of March 2000) awaiting state approval, meaning that Elementis and BEM had to construct and operate the system using New Jersey’s special provisions for “at risk” construction and operation — further proof, if any were needed, of their confidence in it. “This system represents the state of the art today,” Greene said, “because it combines the best available zeolite technology with high-efficiency regeneration and heat recovery, continuous emissions monitoring, and real-time data management, which is an increasingly critical part of the whole compliance picture — and all fully integrated in an efficient turnkey package.”

Pedersen believes zeolite-based systems will soon have wide application wherever large volumes of VOC-laden air are generated — not just in the coatings industry, but for furniture finishing, aerospace manufacturing, semiconductors, pharmaceuticals, and others as well. “Whenever certain classes of reactive VOCs are present,” he says, “especially the ketone compounds used to make sheeting, rubbers, glue, plastics, metal products, and electronics, we are advising clients to look into zeolite concentrator systems because of the lower overall costs, easier maintenance, and reduced fire hazard.”

As for Elementis, Greene says, “We are at the state of the art now, and I believe we are the first facility in the state to use a zeolite concentrator for air pollution control. But the way I see it, state-of-the-art is really where you have to be. In fact, the way we read the regulations today, any company like ours is going to need a system with these capabilities—if not today, then very soon.”

BEM Systems Inc., formerly the Hazardous/Solid Waste Group of Louis Berger & Associates, is a full-service, independent, multidisciplinary environmental and hazardous-waste consulting firm, providing environmental compliance, cleanup, prevention, and risk management services for public- and private-sector clients nationwide. For more information, visit www.bemsys.com; call 908/598.2600. Elementis Specialties Inc. supplies additives to the United States and world coatings industry, serving customers with custom-blended specialty pigments and performance-enhancement products. Elementis Specialties is a division of the Elementis Group, a leading international specialty chemicals group. For more information, contact Jay Greene, Elementis Specialties Inc., 400 Claremont Ave., Jersey City, NJ 07304; call 201/432.0800.