Controlling VOC Emissions from an Engine Test Cell
The Problem . . .
An outboard engine manufacturing plant installed a number of test cells at the end of the assembly line where the engines are removed and run for quality control. The 25,000 SCFM of exhaust emissions from these test cells contained VOCs, which required controls, but also contained a great deal of carbon monoxide (CO) and water vapor.
The Solution . . .
The plant wanted to minimize overall costs by using the existing Regenerative Themal Oxidizer (RTO) for these emissions sources. Concentrator technology was a consideration. Since the control of CO emissions was not an immediate objective for this application or the local regulatory authority, there was no immediate concern with the CO emissions that exited the concentrator system to the atmosphere. The concentrator could adsorb the VOC emissions and eventually desorb them in a much smaller flow rate. This smaller exhaust flow could also be sent into the existing RTO to control the engine test cell exhaust as well as controlling the paint finishing line exhaust.
The presence of a large percentage of water vapor in the process exhaust caused concern regarding the effectiveness of the adsorption system. Vapor-liquid separators could be used to minimize the water introduction into the concentrator but the low winter temperatures could present operational problems. Heat jacketing and insulation were required to prevent freezing. This increased the overall cost of the system, especially when using stainless steel for all component parts in contact with the process exhaust.
Another potential problem regarding the concentrator system was the presence of small amounts of high-boiling oils that may not adequately be desorbed off a concentrator system. The boiling point temperatures of these oils was high enough that even the high temperature desorption that was offered on this concentrator was determined to be insufficient to obtain complete desorption. This problem could be addressed by installing a "sacrificial" guard bed of carbon in front of the concentrator to capture the high-boiling VOCs. But this posed yet another problem. With additional process equipment to purchase and maintain, replenishment of carbon in the beds on a routine basis and proper disposal of the used material was not an attractive option.
To provide a thorough analysis of all control options available, other technologies were presented to the customer. Since the total VOC and CO emissions from the test cells were still a very small concentration, the optimal control technology chosen for treating this emission source was a new RTO. The existing RTO did not have the volumetric capacity to control the concentrated VOC stream from the paint line and flow from the test cells. So a new RTO was needed to control the test cell exhaust.
The engineering study, taking into account the high quantity of water vapor and carbon monoxide emissions from the process, determined that all ductwork between the test cells and the RTO must be constructed of stainless steel to prevent corrosion. This ductwork was also sloped back to the process to minimize carryover of excessive amounts of water to the RTO. The RTO internal insulation and inlet ductwork was also designed to process the high amount of water vapor to minimize erosion of the RTO insulation and corrosion potential of the steel.
The Result . . .
The manufacturing plant is now able to control a very high volume of the total exhaust with its existing, rebuilt RTO now equipped with a new Concentration System. The remaining test cell exhaust emissions are controlled with a new RTO that provides high thermal efficiency to reduce operating costs while obtaining high VOC/CO destruction efficiency -- keeping the facility in compliance for many years to come.
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Contact Anguil Environmental www.anguil.com Phone: (414) 365-6400.
Controlling VOC and NOx Simultaneously from a Plastic Foam Manufacturing Facility
The Problem . . .
A European manufacturer needed to meet local, national and EU emission requirements for VOC and NOx emissions from its plastic foam manufacturing process.
The Solution . . .
The extruded foam web enters the foaming oven where the final product is made. The foam expands in the oven and in the process chemical compounds are emitted.
Compliance with the emission limits required development of a hybrid catalytic system that would concurrently treat the oven air to abate both VOC and NOx limits to achieve <20 mg/Nm3 VOC and <200 mg/Nm3 NOx.
CSM developed a single, skid mounted system using a unique control scheme to achieve performance while eliminating the need of ammonia injection and associated NOx analyzers, considered standard for most SCR systems. The system uses multiple catalyst beds and conserves energy.
The Result . . .
The application of catalysis in a hybrid system to abate VOC and NOx simultaneously allowed the manufacturer to meet its emissions limits. These results indicate that this technique can be applied to cut streams containing excessive ammonia, hydrocarbons, nitrogen bearing compounds and nitrogen oxides.
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Controlling VOCs from a Hot Stamp Foil Manufacturer
The Problem . . .
Rising energy costs prompted a hot stamp foil manufacturer to look into ways to cut their process energy costs. They determined that their recuperative oxidizer was subject to frequent malfunctions and was preventing them from achieving optimal run speeds. A change was needed. Its goal was to achieve a 15 to 20 percent increase in overall throughput from their coating lines. Its current oxidizer required a large amount of natural gas to operate and they hoped to minimize fuel consumption.
The Solution . . .
The hot stamp foil manufacturer had three specific requirements for purchase of a new oxidizer: the ability to reclaim heat for their dryers, the ability to achieve specific VOC destruction rates, and a solution that could be readily integrated with existing operations. The company selected a customized 25,000 scfm RTO with auxiliary heat recovery and enough capacity to handle additional exhaust air flow from future processes. In order to reclaim the heat to fuel the dryers, the supplier's engineers developed a customized heat recovery configuration. The system uses an automated heat recovery damper and a hot air mixing chamber to provide temperature controlled make-up air back to the process dryers. With regenerative technology, the VOCs in the process exhaust provide enough energy to keep the oxidizer operating on its own without burner fuel input. Plus, since the hot stamp foil manufacturer can use excess recovered heat from the oxidizer, they don't have to operate the gas-fired heat sources at the dryer any more, which means they can run more safely and efficiently. The RTO uses engineered ceramic heat exchanger media that provides uniform process air distribution across the heat recovery media while promoting turbulence to ensure VOC conversion. This allows for a design destruction efficiency of 99 percent.
The Result . . .
Operating costs dropped substantially and energy usage is down more than 75 percent.
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Controlling VOCs from Battery Manufacturing
The Problem . . .
A battery manufacturing plant need an emissions control upgrade for their manufacturing process that produces and packages primary and rechargeable alkaline batteries. Hoods above the process lines collect a mix of VOCs from the various production processes and send the contaminants to be oxidized. In 1999, the plant was using two direct-fired thermal oxidizers. However, the units were worn from use and consumed tremendous amounts of natural gas. It was time to upgrade the plant's oxidation process.
The Solution . . .
The plant's goal was to minimize energy use while providing continuous dependable service. They looked at both innovative and traditional technologies for the destruction of a mixed VOC stream, but its best realized value calculation resulted from an RTO technology. The RTO technology achieves high energy savings through a regenerative thermal oxidation design that delivers thermal efficiencies of 95 percent. These systems are able to sustain thermal conditions with the heat released during VOC oxidation. This creates a situation where no additional fuel is required for VOC destruction. The installation was completed during a scheduled 24-hour shutdown. In addition, the RTO unit's operation could be monitored remotely from the supplier's headquarters, which keeps process line maintenance and operating problems at a minimum, since technical issues can be taken care of immediately. Since continuous operation is a must, remote monitoring offers a real advantage to avoiding downtime.
The Result . . .
The unit has been very dependable and cost savings are running at or above the 60 percent energy saving anticipated.
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Controlling VOCs from a Flexographic Printing Press
The Problem . . .
In the spring of 2000, a plastic manufacturing company upgraded their process by purchasing a new printing press which required additional pollution control capacity. At the time, the company had three flexographic printing presses, each with its own afterburner. With only 50 percent primary heat recovery, these afterburners were consuming an enormous amount of natural gas.
The Solution . . .
The company's oxidation solution included an regenerative thermal oxidizer (RTO) (installed in August 2000). The company decided to use regenerative technology because the ceramic media bed does not have the ability to get poisoned like catalytic media sometimes can. A permanant total enclosure (PTE) was designed and installed by the supplier to enable the company to capture virtually 100% of the "fugitive" VOCs that escape the presses. This also allowed the company to achieve capture goals while maintaining ample work space. Instead of putting a small PTE around the presses, the company created a larger PTE around the presses and the warehouse space, which gave them a lot of operating room.
The Result . . .
Since the installation, the company has seen substantial cost savings due to a sharp decrease in their natural gas usage. Since May of 1999, because of the energy crisis, the company's therm has gone up 232 percent. But the billing amount after installing the RTO is actually less. After the RTO was operative, an independent testing agency, conducted compliance tests. The agency not only found that the new RTO supported 99.4 percent destruction efficiency, but physical inspection of the PTE also indicated a capture efficiency of nearly 100 percent.
For More Information . . .
Contact Anguil Environmental www.anguil.com Phone: (414) 365-6400.
Controlling High or Low VOC Concentrations for a Latex Supplier
The Problem . . .
A major supplier of latex to the paint industry faced a particular problem when it looked for a way to reduce emissions of vinyl acetate and other VOCs during the manufacturing process.
Because the latex manufacturer uses a proprietary batch process for latex production, the VOC concentrations in the process exhaust stream vary from almost 0% lower explosive limit (LEL) to a flammable mixture. A large variation in concentration - combined with the 95% destruction efficiency that U.S. regulations currently mandate - poses a problem for the most commonly used technologies.
Catalytic oxidation is often used to promote the oxidation of VOCs at a temperature that is lower than thermally possible. By operating at these lower temperatures, catalytic oxidizers use less fuel, which saves money. The chief drawback is that catalytic units are normally limited to an LEL concentration of less than 25%. Concentrations greater than 25% LEL result in excess heat release in the catalyst bed, which can damage the catalyst. Air dilution can be used to reduce concentrations, but then extra fuel is needed to heat the increased volume.
A second method to control VOC emissions is thermal oxidation using either a regenerative or recuperative heat exchanger. Because of variations in LEL concentrations and heat releases, however, a heat exchanger cannot be properly sized to handle the high heat release while still being efficient enough to make the unit economical to operate with lower LEL concentrations.
A final option is direct flame oxidation in which the process gas is burned in a burner. This, too, is problematic. Although direct flame oxidation works well when VOC concentrations are high, the method requires large amounts of natural gas to be added to the process stream when the process LEL is very low. Otherwise, the mixture will not reach combustibility. Consequently, this method is also uneconomical.
The Solution . . .
The latex manufacturer solved their dilemma with the use of a specialized oxidation system. Based on the standard catalytic oxidizer, the system features a fluidized bed of inexpensive, non-noble metal catalyst. This fluidization, along with the catalyst's rugged characteristics, prevents the catalyst from fouling, and allows the catalyst to be used in streams with both chlorinated and sulfur compounds. These features, along with the system's castable refractory lining and strong carbon steel shell, provided a good base unit.
The system, however, still needed to operate economically while handling the high VOC concentrations. For this, a second burner was added to the system through which the process gas is introduced into the oxidizer. This burner provides direct flame incineration when concentrations reach a flammable level. At this point, the gas is burned as a fuel to provide heat for the system. As a result, the pre-heat burner running on natural gas turns down to a low-fire state to conserve fuel. Since fuel is not burned at 100% efficiency, some of the VOCs make it past the burner. The catalyst oxidizes VOCs that are not oxidized in the burner for a destruction efficiency in excess of 95% (higher destruction efficiencies can be reached by adding more catalyst).
At low VOC concentrations the unit operates as a normal catalytic oxidizer, with the vinyl acetate-laden air being oxidized in the catalyst bed. The catalyst allows for high destruction efficiencies at lower operating temperatures than thermal oxidation. For this application, the operating temperature is set at 700 degrees F.
The Result . . .
The use of such a sophisticated combination direct flame/thermal/catalytic oxidizer allowed the latex manufacturer to solve a potentially cost prohibitive, as well as technologically difficult, problem with a cost-effective, relatively simple solution.
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Controlling VOC Emissions and Solvents from a Flexible Packaging Plant
The Problem . . .
A company selling a range of flexible packaging to customers across the U.S. had an inefficient solvent recovery system. Their product line includes everything from packages for the snack food industry, to extended wraps for multi-packs of toilet paper, to packaging for pet foods, confections, and pharmaceuticals.
The company's 15-year-old carbon bed solvent recovery system was wearing out. It required a lot of maintenance work and consumed significant fuel for steam downs. The system also yielded unrecyclable solvents that resulted in monthly disposal fees. The restricted solvent diet that recovery systems can handle also limited their options in process flexibility.
The company needed to control VOC emissions from seven processes, including five presses (one flexo and four rotogravure) and two wash stations, and also needed to control a wide range of solvents.
The Solution . . .
Rather than rebuild or replace the system, the packaging company chose to install a new RTO, but their location complicated the situation. The plant is in a residential section of town with a hospital across the street. Both factors had to be considered in the air quality model. Perhaps more challenging was the placement site itself. There is a steep, 90-foot bluff immediately behind the plant. The only available site for the unit was between the back of the plant and the foot of this steep hill. Working with engineers from an industrial equipment installation firm; the control technology supplier, packaging company, and the installer, developed a plan for cutting a temporary road through the bluff. This was the only way to reach the site. The operation required moving more than 15,000 yards of dirt, as well as exhaustive logistical planning.
The RTO was built offsite and trucked to the packaging company's facility for installation. During the bulk of installation, the plant continued its normal 24-hour operations. Final connections and testing required a one-day plant shutdown.
The Result . . .
To operate continuously on a 24 hours per day, seven days per week basis, the plant's required VOC destruction efficiency was very high. Stack testing of the installed oxidizer produced an actual destruction efficiency of 98.9% - more than enough to satisfy the regulatory agency.
In addition, the system continues to bring the packaging plant significant savings in operating costs. Compared to the old solvent recovery system, fuel costs have dropped 80%. Plus, the company no longer has to pay for disposing unrecyclable solvent, which had run over six figures a year. The RTO also eliminates the cost of 9,000 pounds of water used for daily steam downs and the plant has been able to take the people they had maintaining their solvent recovery system and put them back into value-adding work.
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Controlling VOC Emissions with a System Integral to the Production Process at a Commercial Bakery
The Problem . . .
The customer required an emissions abatement system as an integral component of a new production line in order to achieve VOC emission compliance while saving money due to reduced costs. The customer is a commercial bakery, Gold Coast Baking of Santa Ana, California, and the CSM catalytic oxidizer needed to be integral to the new bakery oven being provided by Pulver Genau of Tracy, California.
The Solution . . .
The unique oven/oxidizer design incorporated a CSM Worldwide Model 10B Catalytic Oxidizer into a Pulver Genau E4 bakery oven using indirect and direct fired zones. Cost savings were realized via reduced engineering costs, capital investment costs, installation costs and operating costs.
The Result . . .
This first-of-a-kind design resulted in savings in both time and money: only one permit was required for two installed systems, heat circulated into the oven eliminated the need for an additional heat exchanger, operating costs were cut resulting in a 25% fuel savings, and the catalytic oxidizer was incorporated as part of the process, not as an end-of-the-pipe solution.
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Controlling VOC Emissions from a Wire Enameling Plant
The Problem . . .
A wire enameling plant ("the company") in Missouri needed a system that could control odor and VOCs while operating within a tight pressure-control tolerance. Each of the company's enameling process lines produced one hot and one cold source of VOC emissions. The company needed a single system that would initially control 40 process lines, but which also had the reserve capacity to handle an additional 20 lines of potential expansion.
The Solution . . .
After a thorough evaluation of several possible solutions, the company selected a 30,000-scfm regenerative thermal oxidizer (RTO) to control odor and VOCs.
The control technology supplier working with the company's local contractors, erected intricate ductwork to gather VOC emissions from the plant's 40 enameling lines (each of which has two sets of ducts) and efficiently route them to the oxidizer while maintaining specified pressures. Steps were also taken to prevent condensation problems from mixing process air from the two temperature sources. Finally, installation of the ducting had to be accomplished while the plant was in full operation.
The final tie-in and commissioning was scheduled during a six-day shutdown, and the job was finished with time to spare. Testing verified that the system delivered RTO thermal efficiency of 94%, ±2%, and VOC destruction efficiency of >99%. The system maintained steady static oven pressure control of -0.50 inches of water column, ±0.075", and transient pressure control of ovens with a pressure disturbance of >1.0" water column for a duration of five seconds or less.
The Result . . .
The regenerative thermal oxidizer system met all design requirements and proved to have no adverse impact on the company's process ovens.
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Controlling HCl Fume Emissions from a Metal-Working Plant
The Problem . . .
Allomatic Products Company wanted to limit emissions of hydrochloric acid (HCl) from its metal-working plant in Sullivan, IN. A "bubbling" scrubber, installed in 1992, was not doing the job. HCl fumes were causing acidic odors in the neighborhood, as well as a discharge plume.
The company specializes in filters, friction plates and steel plates which it supplies to the aftermarket transmission industry. Friction plates for automobile automatic transmissions were "driving" the problem. After the friction and steel cores are blanked in the press room, they must be acid-etched using HCl.
The Solution . . .
After an engineering analysis, the supplier suggested a system combining a venturi-type wet scrubber with a packed scrubbing tower. Operating parameters were stated as 500 cfm of gas, containing 500 ppm HCl vapors, with 95% or better removal efficiency required.
The Result . . .
Installation was accomplished during a one-week plant shutdown. The system operates twenty hours a day, four days a week, fifty weeks a year. It is operating at better than 98% HCl removal efficiency.
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Controlling Hazardous Air Pollutants from a Hazardous Waste Incinerator
The Problem . . .
A major chemical plant's hazardous waste incineration operation needed to be upgraded to meet new stringent EPA Maximum Achievable Control Technology (MACT) rules. The wastes generated are primarily high BTU, organic materials that can be effectively managed through combustion. The incineration facility burns about 2000 different waste streams in total quantities exceeding 100 million lb./yr. The wastes include hazardous and non-hazardous liquids, sludge's, containerized solids and bulk solids. Since space was limited, throughput capacity had to be increased, maintenance downtime minimized, and energy usage limited due to existing fan capacity.
The Solution . . .
After investigating several retrofit options with respect to probable emissions performance, capital cost, operating and maintenance cost, residue disposal requirements, reliability and ease of construction, the project team decided to remove the waste heat boilers due to secondary formation of dioxins/furans and maintenance issues and to replace the existing twenty year-old scrubber system. The project team selected an air pollution control system that included a quench, scrubber, and wet electrostatic precipitator.
The jet venturi quench rapidly reduces the combustion gas temperature to saturation, thus limiting the time for dioxin/furan formation reactions to occur. The quench also removes large particulate matter and serves as the first stage acid gas scrubber.
Gas flows from the quench to the condenser/absorber scrubber, which is a multiple rod deck design. Scrubber water is re-circulated through a heat exchanger before distribution at the top of the column, which results in the gas being sub-cooled to well below saturation temperature. Particulate greater than 2 micrometers and HCl are both removed at 99+% efficiency in this device. The sub-cooling of the gas removes condensable organics and metals, and results in the growth of sub-micron particles.
The cooled gas flows from the scrubber to a two-stage wet precipitator system. The wet ESPs achieve 99% collection of sub-micron particulate and heavy metals. This allows considerable flexibility for metals feed rates due to the high overall removal efficiencies provided.
The Result . . .
Under worst case conditions, the new APC system successfully demonstrated performance compliance to all RCRA and MACT standards for particulate, chlorine, low-volatile metals (chromium), semi-volatile metals (lead), mercury, and dioxins/furans (PCDDs) when operated at design conditions. Performance efficiencies were in excess of 99.9% for all pollutants.
The system designed embraces the philosophy of "incremental pollution control", where each component of the APC train has a specific function but, in addition, contributes to the reduction of all pollutants generated in the combustion process.
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Destroying Dioxins and Furans in the Baghouse at a Municipal Waste Combustor
The Problem . . .
In 1996, new dioxin rules prompted IVRO to install a powdered activated carbon injection system (PAC) at its municipal waste incinerator in Roeselare, Belgium, to reduce dioxin emission below 0.1 ng(ITEQ)/Nm3. The PAC system operated at 200-230°C. At these temperatures corrosion is minimized, and Spongiacal can be added with screw conveyers. However, the disadvantage of using PAC at high temperatures is the danger of fires in the baghouse. The burning carbon-rich fly ash not only damages the filter bags, but also the dust evacuation equipment. To avoid a plant shutdown, ICVR wanted an alternative technology for dioxin and particulate control.
The Solution . . .
In October of 1998, the plant was equipped with REMEDIA D/F filters, manufactured by W.L. Gore & Associates. This system consists of a GORE-TEX membrane laminated to a catalytically active felt. The felt is composed of chemically active fibers coating a variety of specially produced catalysts. As gases pass through the felt, a catalytic reaction is induced and dioxins/furans are decomposed into harmless gaseous components. The GORE-TEX membrane provides particulate collection, while the catalytic substrate destroys highly toxic gaseous pollutants.
The Result . . .
The REMEDIA D/F catalytic filter system reduced emissions of PCDD/F significantly below 0.1 ng(ITEQ)/Nm3 at 11% O2. The catalytic filters installed three years ago remain active. Several reliability measurements indicate that the measurement company can reliably measure dioxin/furan emissions (+/- 15%) for concentrations as low as 0.01 ng(ITEQ)/Nm3 at 11% O2. In over 100 measurements, the clean gas dust concentrations were below 1 mg/Nm3 (at 11% O2), often below the detection limit of 0.2 mg/Nm3 (at 11% O2).
The plant can operate in compliance with all European environmental rules.
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Controlling Blue Haze and VOCs for a Rubber Curing Operation
The Problem . . .
A rubber curing company needed an affordable solution for their blue haze and low level volatile organic compounds (VOCs) in order to meet regulatory compliance. The Electrostatic Precipitator (ESP) in use was extremely expensive to maintain, and the company was looking to reduce operating costs.
The Solution . . .
After serious technical evaluation, an self-cleaning ceramic filter (SCCF) was installed. To alleviate the maintenance headaches of the ESP, the owner originally inquired about a thermal oxidizer. However, the fuel costs of a thermal system are almost equal to the maintenance cost of an ESP. Because of its fuel efficiency and lower operating costs, a Regenerative Thermal Oxidizer (RTO) was a possible option, but Anguil found that the footprint and the weight of the unit could not provide the flexibility the customer desired. The engineers concluded that nine SCCF systems would be the most effective solution.
One of the major considerations in designing a treatment system for a rubber curing process is that the ducts must be kept clean from any particulate buildup. Large treatment systems, like an ESP or RTO, also involve long duct runs. This combination makes many treatment solutions both costly and dangerous, since particulate buildup can cause duct fires.
The vendor worked with the customer and their process engineers to design a system that greatly reduced duct maintenance cost and provided effective opacity and VOC control. The small footprint of the SCCF allowed them to roof-mount the nine systems that they provided and treat each of the 1500 CFM oven "zones" with direct duct runs. By making shorter and more direct duct runs, the engineers reduced the risk and cost of particulate buildup.
Added benefits of the SCCF include a 40% effective shell and tube heat exchanger, providing even greater cost savings through heat recovery. This flexibility also provides options for future adjustments in pollution control. Because the plant was located in an area that may come under more stringent environmental regulations, vendor SCCF's can be equipped with a catalyst to achieve 95% VOC destruction.
The Result . . .
This SCCF solved the rubber curing company's air pollution problem in the most cost effective and lowest-cost manner.
For More Information . . .
Contact Anguil Environmental
www.anguil.com
phone: (414) 365-6400
Controlling VOCs and Designing Around HBr for a Chemical Manufacturer
The Problem . . .
A major chemical manufacturer required a pollution control system to destroy the halogenated volatile organic compounds (VOCs) emitted during the formulation of PTA. During the production process, methyl bromide is converted to hydrogen bromide. The pollution control system had to be designed to withstand the corrosiveness of the hydrogen bromide and varied organic loadings which alter the temperature of the system.
The Solution . . .
A catalytic oxidation system designed for 90,000 SCFM was used to process the airflow. The presence of methyl bromide in the emission stream presented additional design considerations. The catalyst oxidizes the methyl bromide to hydrogen bromide (HBr). If hydrogen bromide drops below its dew point it becomes corrosive to the equipment. The equipment downstream of the catalyst must be engineered to avoid any "cool spots" where the hydrogen bromide can condense.
The heat exchanger is one potential "cool spot". Without proper design, the heat exchanger could lower the temperature of the air exiting the catalytic oxidizer to below the dew point of hydrogen bromide. To avoid the potential condensation of hydrogen bromide and subsequent corrosion to the system, Anguil incorporated a steam preheater on the incoming process stream before the catalytic oxidizer preventing condensation of HBr on the shell side of the heat exchanger.
The process exhaust from the PTA plant varies in organic loading; therefore, the catalytic oxidizer design must accommodate these varying levels with minimal use of auxiliary fuel. This is accomplished by using a bypass on the shell and tube heat exchanger. Selection of the proper catalyst was also critical to the project. Significant advances have occurred in recent years in catalyst technology have resulted in the development of catalyst suitable for the airstream in this application. The catalyst rack design, including specialty gasketing, eliminated the risk of gas bypassing the catalyst which would result in incomplete destruction.
The Result . . .
This catalytic recuperative oxidation system is currently operating and achieving the regulatory compliance demanded of the PTA plant. With the success of this system, the customer purchased an identical 90,000 SCFM unit and additional systems were installed for PTA manufacturers in the Middle East and Southeastern United States.
For More Information . . .
Contact Anguil Environmental
www.anguil.com
phone: (414) 365-6400
Controlling Heptane and Hexane Emissions from a Pharmaceutical Plant
The Problem . . .
A pharmaceutical company purchased a thermal oxidizer to treat the heptane and hexane exhaust from its system for washing capsules. The unit's tubular design was modified with a catalyst bed to reduce the system’s operational costs. Unfortunately, in its catalytic mode the oxidizer failed to provide the State's required 95% destruction efficiency of non-methane hydrocarbons, which led the U.S. EPA to impose a large civil penalty.
The Solution . . .
An ICAC vendor was called in to solve the VOC problem. The company ruled out the possibilities of catalyst masking and the presence of a poisoning agent such as sulfur, phosphorous, or heavy metals. The vendor also eliminated the possibility that the industrial process stream was being allowed to pass through the oxidizer before it achieved proper operating temperature.
The vendor then conducted a laboratory performance test that indicated that the catalytic stainless steel rings lacked a suitable surface area to achieve more than 50% destruction efficiency of propane and propylene in the test stream optimum. The vendor modified the system design to accommodate a honeycomb catalyst with a 300-cell-per-square-inch ceramic substrate. An alumina washout was used to deposit large quantities of precious metal, e.g., platinum, palladium, and rhodium. The surface area of this replacement catalyst is more than 100 times greater than that of its stainless-steel counterpart-with a cubic foot having more surface area than a football field.
The oxidizer was equipped with a new reactor section to house the nine cubic feet of monolithic catalyst. Follow-up with a flame ionization detector (FID) showed a VOC inlet concentration of 943 ppm and an oxidizer outlet concentration of less than 20 ppm. (A carbon filter was used to eliminate methane emissions.)
The Result . . .
The non-compliant system was successfully retrofitted, bringing the pharmaceutical company into compliance. The company's oxidizer now achieves a 97.8% destruction efficiency.
For More Information . . .
Contact Anguil Environmental
www.anguil.com
phone: (414) 365-6400
Controlling VOC and Styrene Emissions from a Button Manufacturer
The Problem . . .
One of the world's largest button manufacturers needed an emission control system that would destroy VOC and styrene emissions. Three main considerations guided the design of this solution: the need for a system with low operating costs; the control of the high volume, low VOC concentration of the air stream; and the unique characteristics of styrene.
The Solution . . .
After thorough evaluation of several possible solutions, the company selected an ICAC member company to control their emissions. The ICAC member company recommended a unique solution, a Rotor Concentrator coupled with a Catalytic Oxidizer, to destroy the VOC concentration. A key factor was the vendor's ability to lower the volume of air that needed to be treated.
Many of the processes that emit styrene - such as boat building and button manufacturing - have high airflows with low VOC and styrene concentrations. The customer considered a regenerative thermal oxidizer (RTO) and a biofiltration system as other possible solutions. The operating costs of the RTO and the biofilter were much higher than the ICAC member company's solution because these systems had to treat the entire 15,000 SCFM of process air.
The ICAC member company solution reduced the process air that needed to be treated by a factor of 10. The high volume airstream passes through the rotor concentrator wheel where the VOCs and styrene are adsorbed in the bed, purifying the high volume air. This high volume air is then exhausted to atmosphere. The concentrator wheel rotates continuously, transporting adsorbed VOCs into a desorption section where they are desorbed from the adsorptive media with a low volume heated airstream. After being desorbed from the wheel, the air volume has been reduced from 15,000 SCFM to about 1500 SCFM and the VOC concentration of the air stream is increased from 50-200 ppmv to about 500-2000 ppmv. This low volume, high VOC-laden air is then processed by the oxidizer. By isolating and treating the lower air volume, Anguil is able to provide a system with far lower operating costs than other emission control systems.
The ICAC member company was able to further reduce the operating cost of the system by utilizing a catalytic oxidizer to destroy the contaminated air stream. Catalytic oxidation systems typically achieve greater than 99% destruction of styrene with relatively low temperature requirements and with minimal auxiliary fuel consumption.
Another benefit of the rotor concentrator/oxidizer system is the low maintenance cost. The zeolite material has an expected life of 10 years under continuous operation. Additional maintenance savings come from the rotor concentrator wheel’s reliable motor and belt drive that last at least five years and require minimal maintenance.
The Result . . .
The rotor concentrator/oxidizer system provides a cost-effective solution for controlling high air volume, low VOC concentration air flows and exceeds the company’s environmental guidelines.
For More Information . . .
Contact Anguil Environmental
www.anguil.com
phone: (414) 365-6400
Controlling VOC and Odor Emissions from a Chemical Processing Plant
The Problem . . .
An internationally recognized chemical plant sought air pollution control equipment to destroy odors associated with long chain fatty acids and other oxidation products in off- gases vented from in-process storage and processes operations. The plant selected a consulting engineering firm, which developed specifications calling for a catalytic oxidization system to process 500 scfm of exhaust with 99% destruction of all non- methane organics.
The Solution . . .
After a thorough engineering and background evaluation and formal bidding process, the chemical plant selected an ICAC member company to supply equipment to control volatile organic compound (VOC) emissions and the odor problem. Together, the ICAC member company and the plant chose a noble metal catalytic oxidizer with a 1,000 scfm capacity. This system could handle the 500 scfm of process exhaust, plus an additional 500 scfm of dilution air when spikes or high concentrations occur.
The catalytic oxidation system contains several features to enhance its durability and safety:
Given the corrosive nature of the process stream, all wetted components of the oxidation system, including the shell-and-tube heat exchanger and bypass, are 316 stainless steel.
A lower explosion limit (LEL) monitor continuously samples the incoming process stream, and automatically shuts the system down if the VOC concentration is above a preset limit. A dilution value bleeds in fresh air to dilute the process stream if the temperature rise across the catalyst exceeds a preset value. This both protects the catalyst and reduces the risk of explosion. In constructing the oxidizer, ICAC member company engineers addressed a further concern: that condensable components in the process stream could affect catalyst and heat exchanger performance. The vapors processed by the oxidizer tend to leave an oily film inside the ductwork and on the catalyst, possibly reducing its efficiency. The extent to which the vapors foul heat exchanger surfaces is unknown. The ICAC member company considered this in their design of the ductwork and additionally good access for cleaning the heat exchanger.
The Result . . .
The catalytic oxidizer provides ongoing destruction of VOCs and odors, consistent with regulations and corporate environmental objectives, while keeping operation and maintenance costs at a minimum.
For More Information . . .
Contact Anguil Environmental
www.anguil.com
phone: (414) 365-6400
