A manufacturer of insulation films for the electronics industry needed to evaluate the capabilities of four existing oxidizers that treated emissions from its coating lines. The company was concerned that, due to oxidizer deficiencies, it would not meet regulatory requirements. The oxidizers had been manufactured by two different companies. One of them was no longer in business and the other was unable to provide an adequate solution. The customer needed an experienced engineering company that could accurately identify the oxidizers’ deficiencies and provide quality repairs.
After evaluating the service capabilities of several equipment manufacturers and engineering consultants, the company chose the full-service solution of Anguil Environmental Systems. Anguil’s comprehensive preventive maintenance evaluations of the four oxidizers provided detailed recommendations to improve the oxidizers’ performance. The most urgent recommendation saved the company thousands of dollars in operating costs and put the company in compliance.
Anguil’s rigorous 75-point Preventive Maintenance Evaluation (PME) discovered minor problems with three of the units and a major problem with the largest oxidizer, a 13,500 SCFM (21667.5 Nm3/hr) catalytic oxidizer. Anguil’s recommendations for the three smaller oxidizers greatly improved their safety and performance. Many of the cost-saving suggestions were easily performed by the plant’s in-house maintenance staff. However, the larger oxidizer required more intensive application engineering and a comprehensive air pollution control solution.
The 13,500 SCFM (21667.5 Nm3/hr) system had both a primary and secondary heat exchanger. The primary heat exchanger recovers energy from the combustion chamber exhaust and transfers it to the incoming process air stream to reduce fuel consumption. The secondary heat exchanger recovers additional energy from the primary heat exchanger outlet flow and uses this energy to preheat an air source used in the process. In this case, the secondary heat exchanger is integral to the plant’s coating process; it is used to heat the tower dryer of the AISCO coating machine. The plant engineers had noticed a steady decline in the heat available from the oxidizer and secondary heat exchanger. By the time of Anguil’s investigation, the oxidizer took up to six hours to sufficiently heat the coater before production could begin. During the six hours of warm-up, the oxidizer had to be supplied with natural gas. This tremendous fuel consumption led to extremely high operating costs.
Anguil’s internal inspection revealed major damage to the heat exchanger. A third of the front tubes had separated from the bottom plenum and deformed into the second row of tubes, effectively blocking around 25% of flow through the remainder of the exchanger. Anguil’s evaluation also pinpointed several areas where the airflow was bypassing the exchanger, traveling in the gaps between the exchanger and the ceramic insulation and passing through tears in the tubesheet and top plenum. The combination of bypass areas and the tubesheet tears allowed solvent vapors to bypass the combustion chamber, which greatly lowered the destruction efficiency of the oxidizer.
Anguil performed a destruction efficiency test on the oxidizer when the coated web used 100% toluene as a solvent. Under normal conditions, an oxidizer of this type should have little difficulty in attaining better than 98% destruction efficiency. Due to the airflow bypassing the combustion chamber, the oxidizer was achieving only 93.6% destruction efficiency and did not meet regulatory emission requirements.
Replacing the oxidizer would have drastically interrupted the customer’s manufacturing schedule and resulted in capital cost increases that were unacceptable. Anguil’s solution, however, eliminated any production disruptions by performing repairs and design enhancements over several process downtimes. The first step was to immediately replace both the primary and secondary heat exchangers. Anguil designed, manufactured and installed replacement exchangers for this oxidizer. The dismantling, removal and replacement of the exchangers were performed over a three-day weekend when the customer had a scheduled plant shutdown.
The replacement heat exchangers significantly improved the performance of the 13,500 SCFM (21667.5 Nm3/hr) oxidizer. Previously, the oxidizer had to be run for up to six hours to meet the necessary temperature at a fuel cost estimate of $266/per startup. The process air temperature required for the coating machine is now achieved in one hour. The improved efficiency results in operating cost savings of approximately $230 per startup and up to $30,000 annually. The economic impact of the retrofitted heat exchangers went beyond fuel savings; the improved start-up time has reduced plant downtime and increased worker production. The new heat exchangers have also improved the destruction efficiency of the oxidation system and put the company in compliance.
Anguil’s analysis detailed other cost saving suggestions for the company, including:
- Ductwork adjustments for more efficient oxidizer operation
- Heat exchanger maintenance suggestions for all four oxidizers
- Review of safety controls and upgrade recommendations
- Variable Frequency Drive for the fan on the largest oxidizer to accommodate airflow changes more efficiently
- Burner maintenance suggestions
Anguil also performed airflow analysis of all processes. This information will help the company plan for future growth with additional coating lines.
The retrofitted system is currently exceeding the regulatory requirements and providing an efficient heat source for the coating lines. The Anguil service team’s expert troubleshooting and quality turnkey solution capabilities have led to another satisfied customer.
OXIDIZER SERVICE SERIES: PART 2
Having documentation and spare parts readily available is a great start to being proactive and maintaining effective system operation, but what if you could catch a potential issue before it becomes one? Whether it is still on the drawing boards or has been on site for years, your air pollution control system represents a significant investment and a long-term commitment to environmental compliance. A well-crafted maintenance plan for your oxidizer will allow you to get the most from your investment over the entire life of the system.
Many will come to this article hoping for a one-size-fits-all checklist for maintaining an oxidizer system. As a company that offers service on any oxidizer regardless of style or original manufacturer, we at Anguil have long wanted the same. A set recipe for success would certainly make life easier. For those in need of a quick answer or a starting point from which to grow, we do not wish to disappoint. Absent of knowing anything else about the operating context of a particular oxidizer system, our best recommendation for a basic maintenance plan is as follows:
- Gather all the system documentation as listed in Part 1 of our Oxidizer Service Series. Make sure this documentation is readily available to both system operators and service providers.
- Stock the recommended spare parts for your oxidizer system (more on this in Part 3 of our Oxidizer Service Series)
- Establish a monthly checklist of system inspection points and make sure your own operators are comfortable with what to look for and how to record their findings
- Maintain an operator log book or journal of system issues
- Obtain a yearly Preventive Maintenance Evaluation (PME) from an independent or third party oxidizer service provider such as Anguil
- Establish remote access capability to your system’s controls from an oxidizer service provider such as Anguil
Some may choose to take this basic recommendation for a maintenance plan, stop reading here, and run with it. We would agree that anyone complying with all of the steps as outlined above is indeed making a defensible effort at maintaining their oxidizer system; however, having an Oxidizer Service Provider like Anguil visit your site for a couple days could jump-start the implementation of such a plan.
Maintenance Plan Drivers
The following drivers make the decision to implement an oxidizer maintenance plan imperative:
Production Uptime – An informed staff and a transparent maintenance plan will allow for maximum production uptime, prevent costly shutdowns, and enable a prepared response to operational irregularities.
Compliance with Environmental Regulations – Being out of compliance can be costly and a public relations disaster. The language in many air permits requires operators to stock spare parts, keep historical service documentation, and maintain the system according to the manufacturer’s recommendations.
Compliance with Safety Regulations – Compliance codes often require that safety checks be performed on an annual basis for this class of equipment. Anguil incorporates these safety checks as a part of our 75+ point Preventative Maintenance Evaluation.
Operating Cost Reduction – A good maintenance plan will often pay for itself by ensuring that your oxidizer system is running at peak efficiency and with minimal downtime.
Maintenance Plan Building Blocks
The right maintenance plan for one company might not be the right plan for another. Anguil considers the following to be the building blocks of a comprehensive maintenance plan that can be customized to fit the needs of any operating context.
- System Documentation – Gather all your system documentation in one binder as outlined in Part 1 of our Oxidizer Service Series. Make sure this documentation is readily available to both system operators and service providers. We recommend storing inside the control panel.
- Recommended Spare Parts Package – An Oxidizer Service Provider like Anguil can identify the critical components, recommended components, and convenience items that you should stock to maintain smooth operation of your system and limit production down time.
- Annual Preventive Maintenance Evaluation (PME) – Often done by an Oxidizer Service Provider like Anguil. This is not just our advice. This is rapidly becoming part of Permit Codes and Compliance – both environmental codes and safety codes. Anguil’s standard PME program includes a 2-3 day service visit utilizing a 75+ point checklist to ensure your oxidizer is meeting air pollution control standards and is followed by a formal report for your maintenance records.
The next four options can be performed in conjunction with a PME visit or ordered separately as stand-alone services.
- Destruction Removal Efficiency (DRE) Check-Ups – An oxidizer service provider like Anguil can check the VOC destruction efficiency of your system with portable testing equipment or via laboratory analysis of air samples. This service keeps you on track with system performance and verifies compliance. It is ideal as a pre-test to help eliminate “surprises” during expensive formal compliance testing.
- Repeat Operator Training – Maintenance personnel take pride in servicing the equipment if they are familiar with the operation. Years one and two of an oxidizer’s life can present different maintenance challenges than years three through fifteen. Repeat training can keep operating personnel prepared to meet evolving service needs. Repeat Operator Training is showing up in the NFPA codes as well.
- Catalyst Services – At the heart of every Catalytic Oxidizer System is the catalyst bed. Properly maintained, the catalyst bed can provide years of high VOC Destruction at temperatures well under those required for thermal oxidation. Anguil offers a full program of catalyst services including Evaluation and Testing, Rejuvenation, Replacement, and the purchase back of “spent” catalyst for recycling.
- Split Preventative Maintenance Evaluations – Some facilities have little precious downtime for system repairs, so they want to be prepared with the right parts and contractors to act on repairs immediately when their downtime occurs. They may elect a Split-PME scenario, which starts with a one day system evaluation visit by a Field Service Engineer. A second visit is scheduled and the Field Service Engineer returns with all parts and materials identified in the system evaluation, prepared to execute on the service recommendations immediately.
- Semi-Annual Preventative Maintenance Evaluations – For some, the yearly comprehensive Preventive Maintenance Evaluation is not enough. Overall system balancing, operational cost verification, and inventory of spare parts should be conducted semi-annually. Depending on the complexity of your system, you may wish to contact Anguil to perform this service for you.
- Remote Login Capability – Remote log-in could be your lifeline in emergency situations. Establishing this capability is one of the most important things you can do when devising your maintenance plan. Remote Access Capability has recently become a game changer in the oxidizer service world. For the companies and oxidizer systems we service, when the capability is in place, it is both a lifeline during system upsets as well as a “force-multiplier” when our Field Service Engineers are on a particular site. One need only walk into our Service Manager’s office during a live-connection event and see two or three additional heads observing the system operation in real-time while conversing directly with our Field Service Engineer on site. It is akin to getting the experience and knowledge of several engineers on site for the price of one. In today’s world, no oxidizer end-user should be left behind without this critical safety net in place. Don’t wait for an emergency to find out the connection isn’t there. Anguil can also perform routine operational checks remotely and potentially identify developing service issues proactively for a fraction of the cost of an on site visit. Adding this service quarterly is rapidly becoming a popular option. For those with this feature, make sure to regularly test your connection.
- Operating Cost Review – Do you know exactly how much your system should be costing you to run? Are you getting the most for your operating dollars? Anguil offers an Operating Cost Review Program that can answer these questions for you and provide cost savings recommendations tailored for your oxidizer system.
- Operator Log Book – Thorough service history documentation, including a historical account of daily, weekly, and annual inspections, is often an air permit requirement. Like a doctor’s medical records, a comprehensive operator log will help diagnose operating irregularities and could prevent costly malfunctions down the road.
- Weekly Walk-By Inspections – Typically performed by your own personnel. An Oxidizer Service Provider like Anguil can custom design weekly inspection checklists for your specific oxidizer system.
- Deeper Monthly/Maintenance Day Inspection Checklists – For our Monthly Inspections program, we provide a list of the system components needing inspection, independent verification, and/or calibration on a monthly basis. Our goal is to train your maintenance teams to feel comfortable performing the monthly checks on their own.
- Custom Maintenance Plans – Multi-Year and Multi-Facility Packages
- Developing a custom maintenance plan with an Oxidizer Service Provider can result in a strong service relationship built on trust and long-term oxidizer expertise. Anguil’s custom maintenance plans include multi-year deals for individual plants or across multiple facilities. Custom multi-year and multi-facility maintenance plans can offer numerous benefits:
- Smooth Equipment Turnover Between Project Engineering and Production Engineering Teams – Many oxidizer systems are purchased via a project engineering team who then must turn the equipment over to production teams. This hand-off can proceed much smoother if the production team sees that there is a service agreement already in place.
- Reliable Budgeting – Having a multi-year service plan can take some guesswork out of operational budgeting.
- Consistent Service History – even as plant personnel may turn over.
- Knowledge Sharing – Maintaining service history at the plant level can be difficult enough. A corporate level maintenance plan can become a conduit for improved knowledge sharing between plants.
- Uphold Corporate Values – Environmental Compliance is often part of your Corporate Level Mission Statement.
Reliability Centered Maintenance
Anguil recently participated in a three-week-long Reliability Centered Maintenance (RCM) evaluation of an oxidizer system. This particular system treats the exhaust from a critical production line in one of the most highly regulated areas of the country. RCM is a landmark maintenance concept defined in John Moubray’s book Reliability-Centered Maintenance as “a process used to determine the maintenance requirements of any physical asset in its operating context.”
For this RCM evaluation, a team of Anguil Personnel along with the facility’s maintenance personnel, equipment operators, electrical controls specialists, and EHS staff was assembled and guided by an RCM facilitator. The team went line-by-line through the oxidizer electrical schematics, the sequence of operation, the control programs and the environmental permit requirements to define the system’s functions and possible functional failures. Using the framework of the RCM program, the team generated lists of potential redesigns, required procedures, a compulsory spare parts program, and implementation reports for the system as a whole. This was no small task — the final report was over 400 pages long! The evaluation was a significant investment in both money and manpower for both Anguil and the company involved.
Our two biggest takeaways from this experience were:
- This is the level of training that operators of oxidizer systems deserve but rarely get
- The importance of “Operating Context” in determining a suitable approach to long term maintenance of a particular oxidizer system
To further illustrate the idea of operating context, consider that oxidizers today are being installed into production scenarios where they:
- May be allowed to be offline for several weeks or months in a given year
- May force the end-user to stop all production immediately when offline, in some cases triggering “Notices of Violation” and fines upon any upset condition
- May be treating exhaust gas streams that are immediately dangerous to life and health
- May be the sole source of heat for the process to which they are attached
Each one of these different operating contexts can play a major role in the final determination of an appropriate maintenance plan for a particular oxidizer system.
Not everyone can afford to go to the lengths of implementing a formal RCM maintenance program for their oxidizer system. There are also plenty of industries with enough historically acquired experience where such an effort may not be required. However, an effective and custom maintenance plan adhering to minimum requirements can be crafted with help from an Oxidizer Service Company like Anguil and customized to your particular operating context. Such a program will prolong the life of your equipment while staying within the restraints of an operating budget.
In summary, there is no one-size-fits-all solution for crafting a quality oxidizer safety and maintenance program. At Anguil, we strive to offer a full menu of reliability services to make crafting even the most basic maintenance plan an essential and affordable investment. Our experienced service personnel look forward to assisting you in designing the smartest maintenance program for your company.
This is the second of four parts in Anguil’s Oxidizer Service Series. We encourage you to also view Part 1: Better Maintenance Starts With Better Documentation as well as Part 3: Stocking Spare Parts for Your Oxidizer System and Part 4: Oxidizer System Optimization.
A New Jersey pharmaceutical company purchased a thermal incinerator to treat the heptane and hexane exhaust from their capsule wash system. The thermal incinerator’s “tubular” design was modified with a catalyst bed in order to reduce the system’s operational costs. Unfortunately, when operating in the catalytic mode, the oxidizer failed to provide the required 95% destruction efficiency of non-methane hydrocarbons required by the New Jersey Department of Environmental Protection. These odorous emissions led to neighbor complaints and an EPA consent decree, complete with a $175,000 civil penalty. Although the company was proactive in trying to solve the emission problem, the EPA stipulated penalties of $2,500 for every day the violation existed. The original equipment supplier attempted to rectify the problem to no avail and the pharmaceutical company remained in violation of their New Jersey air permit.
After meeting with several potential suppliers, the company selected was Anguil Environmental Systems, Inc. Anguil’s track record with catalytic systems, knowledge of catalyst and engineering strength made them the most likely candidate to tackle the VOC problem successfully.
Anguil successfully retrofitted the non-compliant system and brought the company into EPA compliance. The first step in Anguil’s approach was to examine the reason for catalyst nonperformance. There were several potential reasons for catalyst failure. The possibility of catalyst masking or the presence of a poisoning agent (i.e. sulfur, phosphorus, heavy metals) within the VOC-laden stream was examined; however, no significant levels of any of these agents were detected.
The second possibility was that the industrial process stream was being allowed to pass through the oxidizer before it was brought to proper operating temperature. This would result in the coating of the stainless steel rings with the heptane and hexane hydrocarbons. If this was the case, when the unit was brought to the proper operating temperature, oxidation would occur on the catalyst, leaving a carbon deposit. This type of carbon deposit would result in decreased destruction efficiency and the formation of incomplete combustion products. No signs of these carbon deposits, known as coking, were detected.
Having eliminated these suspects, Anguil conducted a laboratory performance test that indicated the reason for catalyst failure: the catalytic stainless steel rings lacked the proper surface area to achieve the quoted destruction efficiency. This performance test revealed that there was less than 50% destruction efficiency of a propane and propylene test stream. This is an excellent indicator of catalyst failure or inactivity.
Anguil modified the system design to accommodate a honeycomb catalyst. The monolithic catalyst Anguil chose was a 300 cell-per-square-inch ceramic substrate. An alumina washout was used to deposit large quantities of precious metal (i.e. platinum, palladium, rhodium). The surface area of this replacement catalyst is more than 100 times greater than that of its stainless steel counterpart. (Note: a cubic foot of this monolithic catalyst contains more surface area than that of a football field.) The oxidizer was equipped with a new reactor section to house the nine cubic feet of monolithic catalyst. A 95% destruction efficiency guarantee was provided along with the system retrofit.
A follow-up Flame Ionization Detector (FID) was also performed on this retrofit and a carbon filter was added to eliminate methane readings. The FID test results indicated a VOC inlet concentration of 943 ppm and an oxidizer outlet concentration of less than 20 ppm. The company is now EPA-compliant 97.8% destruction efficiency. Anguil is well-known for providing VOC control systems but in this case, they demonstrated their ability to provide answers where others had failed.
OXIDIZER SERVICE SERIES: PART 1
Part of properly servicing your oxidizer system is maintaining the design documentation associated with that system. When it comes to oxidizer design, National Fire Protection Association (NFPA) standards are considered good practice, and those same standards include requirements that should be used for ongoing oxidizer maintenance and system documentation.
The following are critical design documents oxidizer users should preserve that contain information required by the NFPA to implement an overall system reliability plan. Anguil uses the same documents to build and maintain information to offer value-added service on anyone’s oxidizer system, regardless of the original manufacturer. The documents listed with an asterisk (*) are the three most important documents to have on hand and you should always have print copies inside your control panel.
- Process and Instrumentation Diagram (P&ID):The P&ID is the command drawing that summarizes instrumentation, safety devices, operational limits, and control loops. The P&ID typically provides the oxidizer component tag numbers, as well as the number and type of process exhaust pick-ups for the system. The system utility requirements and performance parameters can be listed as well.
- Electrical Schematics:The electrical schematics provide the detailed connectivity of the entire system and is an important tool used for system troubleshooting. It is critical that the electrical schematics are not only kept readily available, but also revised to keep up with system changes.
- Sequence of Operation / List of Set Points & Alarm Conditions:The sequence of operation is a step-by-step description of how the oxidizer is designed to operate. It includes: how it starts, how it brings process exhausts on-line, how it maintains airflow and temperature control, and how it safely shuts down. Set points and alarm conditions of the system are also included in this document. It is important to note that this documentation is required per the National Fire Protection Association’s NFPA 86: “Wiring diagrams and sequence of operations for all safety controls shall be provided” (From NFPA 86: Standard for Ovens and Furnaces, 2019 Edition – Section 18.104.22.168).
- Programmable Logic Controller (PLC) Program: If your system requires a PLC, we recommend you keep a fully documented copy of your PLC program for your records. It is important to know that some oxidizer suppliers may be reluctant to release this information to system end-users because PLC programs can include proprietary control schemes. However, with a signed confidentiality agreement in place, end users should be able to obtain this code. If your oxidizer manufacturer is no longer in business, it is possible to upload the program directly from the PLC, but it may be undocumented and you may need an oxidizer service provider to re-enter the code documentation. Information on Anguil’s PLC programming capabilities can be found here.
- Human Machine Interface (HMI) Program:The HMI (Operator Interface / Operator Touch Screen) is the operator’s window into the workings of the oxidizer’s PLC. The HMI program goes hand-in-hand with the PLC program to control your oxidizer system by displaying data points from the PLC along with set points and tuning parameters the operator will be allowed to adjust from the HMI. The HMI also provides system status messages and/or alarm messages based on the PLCs outputs. A failed display can leave you essentially blind when it comes to operating your oxidizer system safely. If this happens at an inopportune moment, you want to be prepared to download your HMI program to a replacement display from your spare parts inventory.
- Expected Pressure-Temperature Profile:This is one of the more obscure documents to obtain, however, it is pivotal in the development of a reliability plan for your system. Obtaining this information can be as simple as a small table on the P&ID giving the expected temperature and pressure value at various points throughout the oxidizer. It is critical to know your pressure point values in order to set up a regular inspection plan for your maintenance personnel. Ideally, you should have a table showing expected pressure and temperature data at the common process exhaust airflow amounts your production requires. If this is unknown, ask your system provider to provide data for two conditions: at full-oxidizer airflow capacity and at half-oxidizer airflow capacity. Once provided this information, you will be able to approximate the points in-between when establishing your customized inspection checklists.
- Permit Compliance Documents:Compliance documentation requirements vary greatly across local, state, and federal agencies, making it difficult to provide generalized recommendations appropriate for all operation scenarios. At a minimum, Anguil highly recommends summarizing your permit compliance documentation requirements within a single, concise document that includes minimum and operating temperatures and bypass limitations. This document will keep all parties aware of the key compliance parameters to monitor and record with respect to your oxidizer system.
- Bill of Materials / Recommended Spare Parts Lists:Finally, a complete bill of materials for your oxidizer system will allow you to obtain the parts you need to maintain system operation. Ideally, the parts listed in the Bill of Materials would be further categorized as “Critical Spare Parts,” “Recommended Spare Parts,” “Consumable Spare Parts,” “Convenience Items,” “Long Lead Time Components,” etc. This allows operators to make an informed decision on the type and quantity of spare parts to stock based on specific production and compliance requirements. Some air permits actually require that critical spare parts be kept on hand. More detailed information on these categories can be found on the Spare Parts section of our website.
Here are some additional highlights regarding system documentation from the current edition of NFPA 86 Standard for Ovens and Furnaces 2019 Edition:
22.214.171.124 Plans shall be drawn that show all essential details with regard to location, construction, ventilation, piping, and electrical safety equipment. A list of all combustion, control, and safety equipment giving manufacturer and type number shall be included.
126.96.36.199 Wiring diagrams and sequence of operations for all safety controls shall be included.
7.3.3 Operating instructions that include all of the following shall be provided:
(1) Schematic piping / wiring diagrams
(2) Startup procedures
(3) Shutdown procedures
(4) Emergency procedures
(5) Maintenance procedures
7.3.4 When the original equipment manufacturer no longer exists, the user shall develop inspection, testing, and maintenance procedures.
This is the first of four parts in Anguil’s Oxidizer Service Series. We encourage you to also view Part 2: Crafting Your Oxidizer Maintenance Plan as well as Part 3: Stocking Spare Parts for Your Oxidizer System and Part 4: Oxidizer System Optimization.
Anguil Environmental Systems recently completed an emergency media replacement on two Megtec Cleanswitch Regenerative Thermal Oxidizers (RTOs) for a world-wide automobile supplier.
Both systems were 65,000 SCFM (104,325 Nm3/hr) units and built by another supplier approximately 10 years ago for two different automotive facilities in the United States.
Anguil was chosen to replace the RTO media for this world-wide automobile supplier over the original supplier based on its competitive pricing and timely responsiveness.
One of the RTOs was extremely difficult to access being located on a three-story roof and a considerable distance away from the building’s exterior wall. Replacement of the media required removal of the upper half of the RTO and use of a high lift crane to accommodate the heights and distances involved.
At the other facility where production uptime was critical, Anguil’s crew worked double shifts to complete the work over a weekend so that the production was not affected.
Anguil completed the projects early and under budget due to proper planning and customer communication.
A rubber vulcanization company was looking for a new, affordable abatement solution to treat their blue haze and low-level Volatile Organic Compounds (VOCs) in order to meet regulatory requirements. The large Electrostatic Precipitator (ESP) in use was extremely expensive to operate and maintain. The company began their search for a system that offered effective opacity control and could also reduce operating costs. The air pollution control supplier would need the ability to engineer the optimum solution and have the product breadth necessary to apply the correct technology.
After thorough technical evaluation, the plant selected Anguil Environmental to solve their VOC emission problem and put them in compliance. Anguil installed its patented Self-Cleaning Ceramic Filter (SCCF) to eliminate the blue haze and the VOCs.
In order to alleviate the maintenance headaches of their ESP, the owner inquired about a thermal oxidizer. However, the fuel costs of a thermal system are almost equal to the maintenance cost of an ESP for this application. Because of its fuel efficiency and lower operating costs, the 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. Anguil’s engineers concluded that an SCCF was 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.
Anguil worked with the customer and their process engineers to design a solution that greatly reduced duct maintenance cost and provided effective opacity and VOC control. The small footprint of multiple SCCFs allowed Anguil to roof-mount the units and treat 1,500 SCFM (2,407.5 Nm3/hr) over each of the oven “zones” with direct duct runs. By making shorter and more direct duct runs, Anguil engineers reduced the risk and associated costs of particulate buildup.
Added benefits of the Anguil SCCF include a 40% effective shell and tube heat exchanger, providing even greater cost savings through heat recovery. Anguil’s 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, Anguil’s SCCF can be equipped with catalyst to achieve greater than 95% VOC destruction.
After a successful SCCF pilot, Anguil’s engineers worked with the customer to provide the most effective and lowest-cost operating system. Flexibility, experience and constant pursuit of better design resulted in another satisfied Anguil customer.
Hong Kong’s Kai Tak Airport was once the world’s busiest airport and eventually became the world’s largest remediation site once it was closed. When the airport was decommissioned, the government planned to rapidly clean up the site for commercial and residential development. After many years of soil penetration by various fuels and chemicals, the site required an extensive and sophisticated groundwater cleanup. The project consultant needed a treatment system that could destroy at least 95% of the volatile organic compounds (VOCs) and minimize operating cost. The project was highly publicized and generated intense government and public interest therefore the chosen treatment system had to be proven and reliable.
After an extensive evaluation of various VOC treatment solutions the consultant selected an abatement system from Global Technologies, the remediation division of Anguil Environmental. Global’s extensive engineering support and industry-leading reliability, and its history of solving difficult remediation problems around the world, made Global the obvious choice. Global engineers performed a careful evaluation of the application data and recommended a Model 80 Remedi-Cat TM forced draft system. The system processes 8,000 SCFM (12,616 Nm3/hr) of VOC-laden air and provides at least 95% destruction rate efficiency.
Global Technologies’ experience with processing large air flows and varying organic loading was crucial to this project. The proven performance of Global treatment systems provided the Kai Tak project engineers the confidence to design an innovative remediation plan. Global’s vapor treatment system was designed to be the heart of this cleanup strategy.
To aggressively remove the subsurface contaminants, the engineers blanketed the old airport tarmac with 2,000 soil vapor extraction (SVE) wells and 1,000 sparge wells.
The massive airflow was directed from the wells to a single treatment system. Compared to a modular approach that would require more treatment systems to treat a limited number of wells, this strategy provided significant savings in energy, fuel and personnel. Global was up to the challenge; their experience designing oxidation systems for some of the world’s most difficult remediation sites led to an advanced vapor treatment system for Kai Tak.
Global selected a catalyst that utilizes a honeycomb construction to provide superior airflow and low pressure drop. The catalyst selected has undergone extensive technical development and field-testing and was chosen to accommodate the unique airflow volume, the amount and type of VOC, and the desired destruction efficiency of the Kai Tak project.
Another key design feature of Global’s vapor treatment system was the variable frequency drive (VFD). The VFD controls the speed of the system fan, regulating airflow through the system and allowing the oxidizer to handle efficiently the air volume fluctuations from the 2,000-plus extraction wells. With a maximum turndown ratio of 10:1, the VFD can produce energy savings far superior to an inlet vane damper. Global provided the VFD with a particulate filter and housed it in a NEMA 4 enclosure to protect it from the sun and other elements.
Like all Global Technologies’ systems, the Model 80 Remedi-CatTM was manufactured with the highest quality workmanship and materials of construction. The heat exchanger and reactor were constructed of 304L stainless steel with continuous, leak-tested welding around all seams. To withstand the natural elements, the exterior shell was constructed of aluminized steel with a coat of UV resistant polyurethane paint. High-density mineral wool was placed between the inner and outer shells to maintain external skin temperatures at safe levels.
A final significant consideration was worker and equipment safety, which is a major concern for every Global Technologies system and especially important on a high profile project like Kai Tak. With safety in mind, Global has developed a state-of-the-art Programmable Logic Controller (PLC) which allows safe and intelligent operation with minimum risk. The PLC provides immediate troubleshooting, first-out shutdown detection and operator assistance for start-up. Global’s built-in, user-friendly features provide the on-site operators more control, increased up-time, and reduced maintenance costs.
Global Technologies’ understanding of a customer’s unique needs, coupled with the engineering know-how necessary to fulfill these needs, resulted in another satisfied Global customer. The cost-saving strategy of controlling numerous wells with one treatment system was made possible by Global’s ability to accommodate the large and varied airflow from the wells. Global’s aggressive and innovative treatment strategies are helping Kai Tak Airport move into a cleaner and safer 21st century.
Pemaco was formerly a chemical facility located in a light industrial and residential area of Maywood, CA, adjacent to the Los Angeles River. No one knows how long hazardous substances had been leaking into the ground but the operations date back to the 1940’s. Up until closure of the facility in 1991, chlorinated solvents, aromatic solvents, and flammable liquids had all been used in the chemical mixing, blending, storage and distribution processes at this location.
After a fire at the abandoned Pemaco location, the Environmental Protection Agency (EPA) was called in to stabilize the site and conduct an emergency assessment to determine the extent of contamination into the soil and groundwater.
The EPA worked with several environmental consultants to define a detailed remediation plan for the superfund site. It was determined that solvents and other compounds from tanks and drums caused soil contamination deeper than 90 feet. A 14-acre groundwater plume that migrated into a complex aquifer system under residential properties threatened local water supply wells with Perchloroethylene (PCE), Trichloroethylene (TCE), Trichloroethane (TCA), Dichloroethane (DCA) and Vinyl Chloride (VC).
The remediation technologies used would include Electrical Resistance Heating (ERH), Soil Vapor Extraction (SVE), thermal oxidation, acid gas scrubbing and carbon absorption. The goal was to completely remediate the 1.4-acre site of these Volatile Organic Compounds (VOCs) and redevelop it as a public park. The vapor treatment portion of the project combined ceramic core flameless thermal oxidation (FTO) with acid gas scrubbing, vapor conditioning, and a carbon adsorption polishing step to control potential dioxin emissions.
Working with several environmental engineering firms and the US Army Corp of Engineers, Global Technologies supplied a 1,000 SCFM (1,605 Nm3/hr) Flameless Direct Fired Thermal Oxidizer (DFTO) with a caustic scrubber for emission treatment from the SVE units. The vapor treatment system was designed to handle typical averages of 315 parts per million (ppm) but capable of maximum spikes up to 25,000 ppm.
The oxidizer was designed to achieve 99.9% destruction of hydrocarbons with a unique gas-fired burner that generates virtually no nitrogen compounds (NOX) during combustion. The patented surface combustion technology ensures that all emissions are exposed to the high temperature zone only along the innermost surface. Another important advantage of this arrangement is that hot combustion gases are completely contained within the burner and the oxidizer outer shell remains cool. Therefore the flameless oxidizer can be processing toxins in a matter of seconds after ignition.
A gas flow control valve was integrated to reduce operating costs. By reducing gas flow as the energy content of the VOCs increases the oxidizer uses less supplemental fuel for combustion. It operates in response to control signals from a thermocouple located immediately downstream of the oxidizer burner.
Downstream of the oxidizer, exhaust gases flow into the integral scrubber quench chamber via Fiberglass Reinforced Polymer (FRP) ducting. Adjacent to the oxidizer, the skid mounted scrubber uses polypropylene packing to treat the acid gases. It was optimized to reduce the water usage without sacrificing spray coverage and the design allowed for a max HCl loading of 472 lbs/hr.
The flameless DFTO and scrubber were arranged in an induced draft configuration, pulling exhaust through the system and keeping it under negative pressure to prevent the escape of any corrosive gases.
The United States EPA filmed a documentary about the Pemaco remedial action for internal training purposes. The documentary highlights several “firsts” for the EPA including the use of a flameless thermal oxidizer for vapor treatment. More information can be found on the EPA website.
A large consulting and contracting firm owns and operates several ex-situ Thermal Desorption Units (TDUs). Each single-load unit has the capacity to desorb 15 tons of soil per hour at a temperature of 400°F – 900°F (204°C – 482°C). These TDUs have been designed to operate on both chlorinated and non-chlorinated contaminants. They are also approved for use under the Resource Conservation and Recovery Act (RCRA) and Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) as well as private industry sites. Since each TDU has the flexibility to operate on standard hydrocarbon and halogenated hydrocarbon applications, the selected pollution control system has to share this flexibility. Due to varying environmental regulations throughout the country on Hydrogen Chloride (HCL), the selected pollution control system also had to eliminate any HCL generated by the oxidation of chlorinated compounds. Finally, the control systems portability was a crucial factor since this contractor’s profitability is based upon how quickly the system can be mobilized, operated and then demobilized for movement to the next site.
The lack of inexpensive natural gas feeds at many of these sites dictated the use of propane as a fuel source for the oxidation technology. Because thermal oxidation requires operating temperatures between 1600°F – 2000°F (871.1°C – 1093.3°C) , the customer was concerned that this technology would lead to unacceptable fuel and operating costs. After examining various capital equipment options and the corresponding operational costs, the consulting engineer recognized the benefits of a catalytic oxidizer which operates at much lower combustion temperatures. After a thorough technical evaluation and bid process, Global Technologies was selected to solve their VOC problem by providing a mobile treatment package, complete with a Chlorinated Catalytic Oxidizer (Chloro-Cat TM) and HCL scrubber package.
Global’s experience with chlorinated catalytic oxidation and HCL treatment prior to the initiation of this project was extensive. At this point, Global had installed over 30 such systems to treat chlorinated streams from Soil Vapor Extraction (SVE) and airstripper sites. This experience proved invaluable in designing and implementing the proper solution. Each rotary kiln or TDU could be expected to exhaust up to 5,000 SCFM (8,025 Nm3/hr) of desorption air at a temperature between 400°F – 900°F (204°C – 482°C) and a chlorinated VOC concentration of 3,000 ppmv. Utilization of a high-temperature baghouse dust collector on the TDU skid removed concerns associated with dust or dirt plugging of the monolithic catalyst cells.
Global utilized an induced draft FRP fan on the back end of the treatment package due to the high temperature, highly saturated exhaust from the TDU. As with all Global chlorinated catalytic systems, a 316L stainless steel shell and tube heat exchanger was installed in the 316L stainless steel reactor. The chlorinated catalytic system was designed to provide 99% destruction efficiency at a temperature of 500°F – 850°F (260°C – 454°C) to reduce auxiliary fuel usage. Safety systems were installed to ensure no HCL condensation or system corrosion.
The 50′ drop deck trailer, upon which the chlorinated system was mounted, also incorporated a Liquid Propane Vaporizer, a storage area for equipment transport, and an HCL Scrubber capable of 99.9% HCL removal in both caustic and pure water mode.
The most recent compliance testing of this turnkey package demonstrated over 99% destruction of all compounds. The result is another satisfied Anguil client.
A Fortune 50 company implemented a remediation system to collect and treat polluted groundwater from a site in Central New York and prevent impacted groundwater from flowing into local waterways. An engineering and construction firm (EPC) was hired to design and build an effective, efficient groundwater treatment system. Primary treatment of the polluted water was to be accomplished using air strippers and the effluent then sent to a separate offsite facility for final treatment. The VOCs liberated from the groundwater by the air strippers, including benzene, chlorobenzene and dichlorobenzene, require treatment before being released to the atmosphere.
The design-builder required an air pollution control system which could destroy 99% of the VOCs and safely remove any of the resultant inorganic acid gasses that would be formed. As this was a long-term project, the VOC control system needed to be highly reliable and provide low operational costs.
After a thorough evaluation, the design-build consultant selected Anguil to provide the VOC treatment solution. Anguil’s extensive engineering support, industry-leading reliability, and history of solving difficult halogenated destruction problems around the world made them the obvious choice. Anguil engineers recommended a Model 50 Regenerative Thermal Oxidizer (RTO) with an Acid Gas Scrubber. The system is capable of processing up to 5,000 SCFM (8,025 Nm3/hr) of VOC-laden air while providing 99% VOC destruction efficiency and 99% removal by weight of Hydrochloric Acid.
Anguil’s engineering resources and experience processing halogenated contaminants were crucial to this project. In the Anguil two chamber RTO, polluted air is preheated as it passes over ceramic media beds located in the energy recovery chamber. From there, the process air moves into the combustion chamber where the Volatile Organic Compounds (VOC) are oxidized. Heat from the hot air stream is then recovered by the second ceramic media bed before being exhausted to the acid gas scrubber. A flow diverter poppet valve switches the airflow direction so both energy recovery beds are fully utilized, thereby reducing the auxiliary fuel requirement as much as possible. Anguil’s two chamber RTO is designed to achieve a heat recovery of 95% TER and results in significantly lower operating costs than other thermal oxidation technologies.
After exiting the RTO, the acid gas laden air is processed through a countercurrent wet scrubber that removes and neutralizes inorganic acids. In the scrubber, a quench system first brings the air temperature down via evaporative cooling by spraying water into the air stream. The cooled air then leaves the quench and enters the bottom of a countercurrent packed tower scrubber. In the tower, a recirculating solution of caustic water is sprayed into the top of the tower and cascades down over the packing material. Any acid gasses remaining in the air stream are absorbed into the water and neutralized by the caustic solution into a salt (brine) solution. To replenish the neutralizing agent, sodium hydroxide solution is added to the recirculating water through pH controls. Similarly, as the brine solution concentrates, ORP/conductivity controls allows saltwater blowdown to leave the system and adds fresh make-up water as necessary.
The specified vapor treatment system included several design features that ensure safe and effective operation in the expected environment. First, an induced draft arrangement was utilized where the process fan is located downstream of the scrubber. An induced draft arrangement is preferred for halogenated applications because it creates a negative air pressure through the entire system where acid gasses are present, minimizing the potential leaking of corrosive gasses which can be forced out of a system under positive pressure. Leakage of s corrosive acid vapors produced by the RTO from the oxidation of halogenated hydrocarbons from equipment connections and penetrations y can corrode the outer shell of the equipment and surrounding environment, as well as posing human health and safety concerns.
Special consideration was given to the materials of construction to ensure performance and reliability in the corrosive environment. Upgraded materials of construction selected for key areas of the RTO are field-proven from Anguil’s many halogenated installations. For example, RTO outer reactor shells were constructed of carbon steel but internally coated with a specialty coating to resist hydrochloric acid corrosion from the inside out. Poppet valves were fabricated from a high nickel alloy, while transitions from the RTO outlet plenum and the acid gas scrubber quench were constructed of hastelloy. The scrubber tower, sump and stack were all fabricated out of FRP (Fiberglass Reinforced Plastic).
Equipment location at the facility was carefully selected to reduce installation costs and minimize equipment downtime. The scrubber was installed inside the treatment building, eliminating the concern of freezing during cold months and costs associated with winterization. The oxidizer was placed outdoors adjacent to the treatment building and near the scrubber system to eliminate extensive ductwork runs.
Anguil’s understanding of the customer’s unique requirements and engineering knowledge of the detailed process conditions resulted in an efficient and reliable system and ultimately another satisfied Anguil customer.