Air Pollution Control Innovations

Catalyst Calciner Particulate SO2 Scrubber

Posted by Andy Bartocci on Tue, Jan 18, 2022 @ 08:00 AM

Catalyst Calciner ScrubberA catalyst production facility operates a calciner that generates a small stream of hot dirty gas. The exhaust is cleaned using a particulate/SO2 scrubber followed by a vertical entrainment separator.  The configuration is problematic for operation.  The scrubber requires a long duct run from near grade to the scrubber inlet flange.  There is a U-shaped bend to the inlet flange.   Particulate condenses in the duct and plugs over time.  The process is routinely shut down to clean out accumulated material. This limits production capacity.  The customer sought to redesign the scrubber to increase production while maintaining as much of the original equipment as possible.

The customer selected Envitech to redesign and supply a scrubber to be retrofit into the existing system.  The scrubber inlet was replaced with a high efficiency Hastelloy Venturi scrubber for particulate removal.  The Venturi length was significantly decreased and oriented at an angle to the entrainment separator inlet.  The shorter distance and angled orientation significantly reduced the duct run from the calciner outlet to the scrubber inlet, minimizing fouling potential.

The top of the entrainment separator was replaced with a packed bed absorber to neutralize and remove SO2.  Structural modifications to the existing vessel ensures the  new packed bed is well supported.

After the Venturi, the gas enters the bottom of the packed bed and travels vertically upward, counter current to downward flowing water.  Excess water from the Venturi and the packed bed collects in a common sump.  Caustic solution injected into the recirculation line neutralizes acid gases.  Liquid recirculates back to the Venturi throat and top of the packed bed.  The gas passes through a vertical entrainment separator above the packing to remove water droplets before exiting the system.

The scrubber was put into service in early 2021.  A continuous emissions monitoring system (CEMS)  confirms emission limits are met. The duct clean out time has been reduced from 24 to 36 hours to < 1 hour.  System uptime has improved from < 60% to > 80%, enabling higher production capacity. The Venturi scrubber is significantly smaller in size, making replacement cost less expensive.   The scrubber is designed to meet the process conditions below:

  • Flow rate: < 1,000 acfm
  • Inlet Temp, 400 oF
  • Particulate removal: > 99.8%
  • SO2 removal: > 99.9%

Click on the link below to download literature about the catalyst Calciner scrubber.

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Topics: Venturi scrubbers, Scrubbers, SO2 Scrubber, Acid Gas, Packed Bed Absorbers, Packed Bed Scrubbers, Wet Scrubbers

Lithium Extraction Chlorine/HCl Scrubber

Posted by Andy Bartocci on Tue, Jan 04, 2022 @ 08:30 AM

1144 Lithium Extraction ScrubberA dual purpose, low flow scrubber is needed for a facility that extracts lithium from geothermal brine. The scrubber treats a chlorine (Cl2) rich stream from a chlor-alkali process and HCl from a caustic storage tank vent line.  The scrubber is installed outdoors in a desert environment with significant seismic and wind requirements.  Temperatures reach 113oF in the summer.  The furthest emission source is 70 ft away. The scrubber will use and induced draft (ID) fan to pull exhaust gas from the upstream sources. The fan must be corrosion resistant and capable of pulling a low flow rate draft  across the pressure drop of the inlet ductwork and scrubber.

The customer selected an Envitech packed bed scrubber.  The scope of supply includes a fiber reinforced plastic (FRP) packed bed absorber, instruments, control system with HMI display, pre-assembled recirculation pump, piping, valves, and fittings, interconnect duct, and an FRP ID fan.  Instruments are pre-mounted in the piping and pre-wired to the control system.

The Cl2 scrubbing reaction is exothermic.  A dilution air damper on the HCl tank vent line dilutes pollutant concentrations to a range that keeps the scrubber from getting too hot.  It also provides enough flow for the minimum cross-sectional area needed to house the packing.  The packed bed vessel and ductwork are self-supporting for wind and seismic.  A high-performance mesh pad at the top of the scrubber removes acid aerosol droplets formed in the scrubber.  The recirculation liquid operates at a high pH. The scrubber needs to achieve 99.98% removal for the worst-case loading conditions.  The scrubber height and mesh pad  work together to achieve performance guarantees.

The scrubber will be delivered in the first quarter of 2022 and is designed to meet the following design conditions:

  • Inlet flow rate – 400 acfm
  • Inlet temperature – Ambient
  • Max HCl and Cl2 discharge limit < 5 ppmv
  • Removal efficiency > 99.98%
Click on the link below to download literature on this application and other literature..

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Topics: Scrubbers, Acid Gas, Packed Bed Absorbers, Packed Bed Scrubbers, Wet Scrubbers

Medical Waste Incinerator Scrubber MACT Standard Compliance

Posted by Andy Bartocci on Wed, Sep 01, 2021 @ 07:50 AM

Medical waste scrubber DHSThere are several different waste incinerator source categories controlled by EPA standards under the Clean Air Act (CAA). These include hazardous waste combustors (HWC), sewage sludge incinerators (SSI), municipal solid waste (MSW) incinerators, commercial and industrial solid waste (CISWI) incinerators, and Hospital, Medical, and Infectious Waste Incinerators (HMIWI). Each incinerator type has its own Maximum Achievable Control Technology (MACT) standard which establishes technology based limits for emitted HAPs. MACT standards are part of the National Emission Standards for 

Medical Waste Venturi DHS

Hazardous Air Pollutants (NESHAP) and are applied to source categories that pose adverse risk to human health by the emission of hazardous air pollutants (HAPs).  The HMIWI MACT standard for medical waste incinerators is the most challenging of the incinerator source categories. This standard controls particulate (PM), hydrogen chloride (HCl), sulfur dioxide (SO2), lead (Pb), cadmium (Cd), mercury (Hg), dioxins/furans (D/F), nitrous oxide (NOx), and carbon monoxide (CO). Emission limits depend on the incinerator size and weather it is a new or existing source. Small incinerators are less than 200 lb/hr of waste throughput, medium incinerators are between 200 lb/hr and 500 lb/hr, and large incinerators are greater than 500 lb/hr.

Envitech recently completed a project for two medical waste incinerators at a Midwest research facility. These are the first new medical waste incinerators installed in the United States since Envitech installed a 525 lb/hr medical waste incinerator at a research facility in Galveston, TX in 2013.

The scope of supply includes two medical waste incinerator scrubbers and a water treatment system to treat the blowdown from both incinerators. The incinerators are permitted as new, medium size incinerators. Ozone injection is integrated into the system to meet a NOx limit of 67 ppmv. The systems include pre-assembled pumps, piping, valves, and fittings to minimize installation time and cost. The pre-assembly provides long term rigidity, consolidation of space, longer up-time, and improved safety for operators. A description of the process arrangement can be found in this link to an earlier blog post.

Stack testing was performed in June 2021 for both incinerators. Test results confirm the Envitech system reduced emissions well below MACT standard limits, providing a comfortable margin for compliance over the range of operating conditions and waste feed. Below is a summary of stack test performance.

Parameter Emission Limit Result, %Limit
PM < 0.0095 gr/dscf 17.9
Pb < 0.018 mg/dscfm 8.9
Cd < 0.0098 mg/dscfm 4.6
Hg < 0.0035 mg/dscfm 25.7
D/F < 0.014 ng/dscm TEQ < 1
HCl < 7.7 ppmv dry < 1
SO2 < 1.4 ppmv < 1
NOx < 67 ppmv dry 24

Click on the link below to download literature on medical waste incinerator scrubbers.

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Topics: Scrubbers, MACT Standards, Medical Waste Incinerator Scrubber, Incinerator Scrubber, HMIWI Scrubber, Stack Testing, Packed Bed Absorbers, Packed Bed Scrubbers, Wet Scrubbers

SO2 Scrubber for Refinery and Petrochemical Applications

Posted by Andy Bartocci on Mon, May 03, 2021 @ 10:20 AM

A common wet scrubber air pollution control application is the removal of sulfur dioxide (SO2) and related compounds from combustion processes. This class of compounds is often referred to as SOx. The formation of SOx and SO2 occurs from sulfur bearing fuels or materials oxidizing to SO2 upon combustion. SO2 has negative health effects and can contribute to respiratory illness, especially in children, the elderly, and individuals with pre-existing conditions.   In addition to health effects, SO2 contributes to acid rain which can harm plants, trees, rivers, streams, and lakes. SO2 also reacts with other compounds in the atmosphere to form small particles that contribute to particulate matter (PM) pollution and regional haze otherwise known as smog. Regulatory agencies often control SO2 not only to minimize harmful health affects but to reduce regional haze.

Packed bed scrubbers are often considered the best available control technology (BACT) for SO2 removal. Below is a summary of SO2 exhaust streams Envitech has treated using packed bed scrubbers.

  • Waste oil refinery waste gas thermal oxidizer and direct fired heater
  • Refinery sulfur recovery unit (SRU) thermal oxidizer
  • Geothermal power generation regenerative thermal oxidizer
  • Secondary lead smelter furnace
  • Mineral processing furnace
  • Catalyst regeneration kiln
  • Ceramic tile kiln
  • Hazardous waste combustor
  • Medical waste incinerator
  • Marine diesel engine

In these applications Envitech has treated SO2 loads as high as 48 tons per day and achieved efficiencies exceeding 99.9% removal. Gas flow rates can vary from < 500 cfm to more than several hundred thousand cfm.

HOW DOES THE TECHNOLOGY WORK?

An example of a large refinery/petrochemical thermal oxidizer SO2 scrubber application illustrates the technology. Below is a summary of design conditions. Liquid discharge limits for chemical oxygen demand (COD) and biochemical oxygen demand (BOD) require oxidation of the blow

Petronas PFD

down.

Design Conditions

  • Flow rate: 300,000 acfm
  • Temperature: 1560oF
  • SO2: 300 lb/hr
  • Chemical oxygen demand (COD): < 200 mg/l
  • Biochemical oxygen demand (BOD: < 50 mg/l
  • SO2 removal > 99%

The above figure shows the scrubber equipment arrangement. Waste gas, fuel, and air are fed into the thermal oxidizer. Combustion in the thermal oxidizer generates exhaust gas of 300,000 acfm @ 1,560oF with 300 lb/hr of SO2. The first step of the scrubbing process cools the gas to saturation using adiabatic cooling through evaporation of water. Excess water flows into the packed bed absorber sump.

The next step is SO2 absorption via mass transfer promoted by high efficiency packing media. The gas flows vertically upward, counter-current to downward flowing recirculation water. Neutralization via caustic addition improves the SO2 absorption rate. An entrainment separator at the top of the packed bed absorber removes water droplets in the gas before exiting the system. Water from the absorber sump is recirculated to the quencher and to the top of the packed bed. Make-up water replaces evaporation and blowdown losses.Petronas GA

The SO2 load is low enough that the scrubber absorber sump can serve as an oxidation tank. Air is sparged into the sump to oxidize sulfites (SO-23) to sulfates (SO-24) in order to meet COD and BOD limits. Caustic addition ensures sulfate formation and minimizes sulfur dioxide off-gassing. Larger SO2 loads may require external oxidation tanks.

The adjacent figure shows a typical arrangement to handle 300,000 acfm of gas flow. The system is modularized with 12 feet diameter shop fabricated vessels. Recirculation pump skids and aeration pump skids are pre-assembled in the shop. Instruments are pre-mounted in the piping assembly where possible and pre-wired to a junction box on board the skid. Shop fabrication and assembly minimizes installation time and cost.

Advantages of a packed bed scrubber includes:

  • High removal efficiency
  • Proven technology
  • Low capital cost
  • Automatic operation
  • High reliability, low maintenance

Click on the link below to download literature about SO2 scrubbing.

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Topics: Scrubbers, SO2 Scrubber, Acid Gas, quenchers, Packed Bed Absorbers, Packed Bed Scrubbers, Wet Scrubbers

Refinery SRU SO2 Scrubber

Posted by Andy Bartocci on Mon, Apr 26, 2021 @ 08:30 AM

SO2 Scrubber ModelA refinery is upgrading an SO2 quencher-scrubber treating incinerator exhaust from a thermal oxidizer of a sulfur recovery unit (SRU).   The quencher is a re-purposed eductor type Venturi that is at end of life and will be replaced.  Scrubber recirculation water passes through a heat exchanger to subcool the gas, eliminating make-up water.  Upstream heat recovery is removed which increases the gas flow rate to the scrubber.

Duct design to the new quencher must ensure flange connections properly mate and will withstand stresses and loads.  A 180o ductwork bend makes the final connection to the quencher.  Of particular concern is the heat load thermally transmitted from the duct flange to the mating quencher flange. 

Refinery VS SO2 ScrubberThe customer selected Envitech to provide a replacement quencher and to make scrubber modifications to accommodate higher gas flow.  The new quencher is an Envitech design sized to fit into existing footprint, platforms, and flange connections.  Water injection through open ports in the quencher throat eliminates a spray nozzle to improve reliability and maintenance.  Recirculated water to the quencher is significantly reduced. Existing pumps are oversized but reused by recirculating excess water from the discharge to the pump return.  Scrubber packing and mist eliminator are redesigned using high performance components for larger gas flow and reduced pressure drop.

Envitech performed a thermal study using SolidworksTM modeling on the flange connection between the ductwork and mating quencher inlet flange.  Study results were used to ensure proper material selection.  Scope of supply includes two 90o refractory lined duct elbows connecting to the quencher.

The elbows are insulated with a rain shield. The connecting 90o elbow to the quencher is mitered with a flange and transition section using high temperature alloy.  All supplied equipment is compliant with refinery quality and design specifications.  Coordination with the end-user and 3rd party engineering firm ensures fit-up and proper mechanical design for interconnecting ductwork and connections.

The scrubber upgrade meets the below design parameters and allows the plant to safely to operate with higher flow while re-using a substantial amount of existing equipment.

Design Value
Flow rate, acfm 10,400
Inlet temp, oF 1,500
SO2 load, lb/hr 223
SO2 removal > 99.9%

Click on the link below to download literature about this application.

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Topics: Scrubbers, SO2 Scrubber, Acid Gas, quenchers, Packed Bed Absorbers, Packed Bed Scrubbers, Wet Scrubbers

Thermal Oxidizer HCl Scrubbers for Vinyl Chloride Facilities

Posted by Andy Bartocci on Mon, Apr 12, 2021 @ 08:30 AM

Illumina HCl ScrubberHCl emissions are encountered in a wide range of applications including hazardous waste combustors (HWC), medical waste incinerators, pharmaceutical production, and ceramic tile manufacturing. There is a wide range of performance requirements depending on the application and applicable state or US EPA standard. Below is a summary of performance requirements for some of these applications.

  • Hospital, medical, and infectious waste incinerator (HMIWI) MACT standard: 5.1 to 15 ppmv depending on the size of the incinerator and whether it is an existing or new incinerator.
  • Hazardous waste combustor (HWC) MACT standard: 32 ppmv for existing incinerators and 21 ppmv for new incinerators; adjusted to 7% O2.
  • Ceramic tile kiln scrubber: > 97% removal
  • Pharmaceutical manufacturing RTO scrubber: > 99% removal
A specific HCl application is the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Polyvinyl Chloride and Copolymers (PVC) Production. The US EPA has granted petitions for reconsideration of the emission limits in the 2012 final rules for process vents, process wastewater, and stripped resin for major and area sources. A typical exhaust source from these facilities is treated by a thermal oxidizer followed by a quencher and a packed bed scrubber.  HCl loads are high and can range from 10,000 ppmv to peak loads of 25,000 ppmv. The proposed new NESHAP rule reduces HCl limits from 78 ppmv to 0.64 ppmv for existing sources. New sources must meet an emission limit of 0.17 ppmv. These are challenging limits and require greater than 99.998% removal efficiency.

Dal_Tile_installIt is well known that gaseous HCl readily absorbs into water and can be removed with high efficiency with caustic addition. The challenge however is that a fraction of the inlet HCl condenses into acid aerosol when hot gas from the thermal oxidizer contacts water in the quencher. The aerosol quantity formed and the particle size distribution (PSD) of the acid droplets vary from process to process. Predictive models to accurately estimate these values are limited and imprecise. In some cases as much as 20% of the HCl can form an acid aerosol fog. Aerosol carry-over exhausting from the scrubber will show up in stack tests and contribute to plant emissions.

It is common for HCl scrubbers to utilize mesh pads above the packed bed to remove aerosol droplets before exiting the scrubber. As noted above, many applications require 97% to 99% removal efficiency. This arrangement is generally adequate for these removal efficiencies. The proposed NESHAP standards for vinyl chloride facilities, however, requires higher efficiency. This increased efficiency demand requires additional consideration in the scrubber design and mist eliminator to guarantee performance. Facilities should rely on experienced scrubber suppliers that understand HCl aerosol and account for it in the scrubber design to guarantee emission limits.

Click on the link below to download HCl scrubber literature.

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Topics: Scrubbers, Incinerator Scrubber, quenchers, Packed Bed Absorbers, Packed Bed Scrubbers, Wet Scrubbers, HCl Scrubbers

Secondary Lead Smelter SO2 Scrubber

Posted by Andy Bartocci on Tue, Mar 30, 2021 @ 08:00 AM

Secondary lead smelters recycle lead bearing scrap metal, primarily lead acid car batteries, into elemental lead or lead alloys.  Metal from the batteries are remelted in blast or reverb furnaces and then refined in secondary smelters. The batteries contain high amounts of sulfur which oxidizes to SO2 in the furnaces.SO2_Scrubber_Lead_Smelter

An unutilized secondary lead smelting facility was retrofitted with new process equipment to restart operations. Air pollution control equipment was needed to achieve greater than 96% removal of peak loads of up to 4,500 lb/hr of SO2 from the furnace exhaust. 

The customer selected an Envitech packed bed scrubber to meet emission requirements.  Three combustion sources are combined in a duct header into a forced draft fan. The fan provides motive force through the scrubber.

The first scrubber step  is an evaporative quencher to cool the gas to saturation. The quencher is constructed from T316SS and is a low pressure drop Venturi to provide turbulence for rapid quenching with a wide turn-down ratio. A fiber reinforced plastic (FRP) elbow connects the quencher to a 10 foot diameter FRP absorber vessel.

Gas from the quencher passes vertically upward through a packed bed, counter-current to downward flowing recirculated water.  Scrubbing water and excess quench water are collected in a common sump and is recirculated to the top of the packed bed and quencher. 

A pre-assembled recirculation pump skid with redundant pumps was supplied with the scrubber.  Instruments were pre-mounted and pre-wired to a control box on the skid.

A dilute solution of plant-supplied sodium hydroxide is metered into the scrubber recirculation line to neutralize acid gases and is controlled by the recirculation liquid pH.  A blowdown stream purges the system of reaction products and is controlled by conductivity.  Blowdown liquid is treated by separate oxidation tanks to convert sulfite reaction products to sulfates.

After the packed bed, the gas passes through a chevron style mist eliminator above the packing material to remove water droplets.  A wash header below the mist eliminator provides a periodic wash to keep the chevrons clean.  Finally, the gas exits the system and is exhausted through a stack.

The scrubber has been operational since 2010 with good result.  Below is a summary of design and performance results.

Design Value
Flow rate, acfm 60,000
Inlet temp, oF 400
Peak SO2 load, lb/hr 4,500
SO2 removal > 98%

Click on the link below to download literature about this application.

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Topics: Scrubbers, SO2 Scrubber, Acid Gas, quenchers, Packed Bed Absorbers, Packed Bed Scrubbers, Wet Scrubbers

HCl Scrubbers for Regenerative Thermal Oxidizers (RTO's)

Posted by Andy Bartocci on Wed, Mar 24, 2021 @ 11:05 AM

Regenerative thermal oxidizer’s (RTO’s) are thermally efficient devices used to destroy low concentrations of volatile organic compounds (VOC’s). Chlorinated compounds, if present, oxidize into hydrochloric acid (HCl) which must beIllumina HCl Scrubber removed after the RTO.

Two examples are Carestream Health in Rochester, NY, a health care products supplier, and Illumina in San Diego, CA, a biotechnology provider.  Facilities at both companies generate low concentrations of chlorinated VOC’s.  Control devices are needed to remove HCl emissions downstream of RTO’s used to meet VOC emissions.

Envitech packed bed absorbers were selected to treat the RTO exhaust gases.  The first step in the scrubbing process is an evaporative quencher to cool the gas to saturation.  A horizontal quencher simplifies ductwork and installation cost.  Al6XN construction provides corrosion resistance.es are Carestream Health in Rochester, NY, a health care products supplier, and Illumina in San Diego, CA, a biotechnology provider.  Facilities at both companies generate low concentrations of chlorinated VOC’s.  Control devices are needed to remove HCl emissions downstream of RTO’s used to meet VOC emissions.Envitech packed bed absorbers were selected to treat the RTO exhaust gases.  The first step in the scrubbing process is an evaporative quencher to cool the gas to saturation.  A horizontal quencher simplifies ductwork and installation cost.  Al6XN construction provides corrosion resistance.  

The quencher is followed by a fiber reinforced plastic (FRP) vertical packed bed absorber with gas flowing vertically upward, counter current to downward flowing water.  Excess water from the quencher and packed bed collects in the absorber sump and recirculates to the quencher and packed bed.  A dilute caustic solution (NaOH) is injected into the discharge side of the recirculation pump to neutralize HCl.  A blowdown stream purges the system of reaction products.   Caustic injection and blowdown are controlled by pH and oxidation reduction potential (ORP).

Gaseous HCl readily absorbs into the scrubber recirculation liquid.  A fraction of the HCl forms a submicron aerosol as gas contacts water in the quencher to cool the gas.  The aerosol is removed by a properly designed mist eliminator.  Gas calculations are used to estimate the fraction of acid aerosol based on gas dew point and partial pressures of water and acid.  The mist eliminator must be capable of removing aerosol at the expected concentration and droplet size distribution. This  impacts the mist eliminator selection, vessel size, and pressure drop of the system.

The scrubbers were put into service and effectively operate on a continuous basis with minimal operator management. Operating parameters and performances are summarized below.

Design Carestream, NY Illumina, CA
Flow, acfm 6,000 4,000
Inlet Temp, oF 585 230
Inlet HCl, lb/hr 92 10
HCl Removal Efficiency, % 99 99

Click on the link below to download literature about this application.

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Topics: Scrubbers, Incinerator Scrubber, quenchers, Packed Bed Absorbers, Packed Bed Scrubbers, Wet Scrubbers

Oxygen Strippers Using Natural Gas

Posted by Andy Bartocci on Tue, Jun 09, 2020 @ 08:30 AM

Oxy Petroleum Stripper TowersVintage Petroleum, LLC, a subsidiary of Occidental Petroleum Corporation operates oil and gas fields in Lost Hills, California, northwest of Bakersfield. The fields operate steam boilers that use nearby canal water. High concentrations of dissolved oxygen in the canal water caused excessive corrosion in the boilers.

Vintage was looking for an effective means to reduce oxygen content in the canal water to prolong boiler life and reduce maintenance costs.

The customer selected Envitech to design and build two stripper towers. The towers use high pressure natural gas to strip oxygen from the canal water. The water is pumped 1,000 feet from the canal to the tower locations. After stripping to remove oxygen, the water is pumped to an existing fresh water tank.

The vessels are constructed of carbon steel with a 3/16 inch corrosion allowance and painted internally and externally. The
vessels are fabricated in accordance with ASME Code Section VIII Division I requirements and stamped. The maximum vessel design working pressure is 100 psig at a maximum design temperature of 300 °F and also designed for half vacuum.

The lower vessels are 6 feet in diameter. The upper packed bed sections are 4 feet in diameter. The overall vessel height is 27 feet.

The first system was installed in 2013. The second system was installed in 2014. Both systems are operational and the facility reports success in prolonging boiler life. Designed to the parameters summarized in the adjacent table, the stripping towers resulted in an innovative process solution to solve a unique operational problem.

  • Gas flow rate, mscfd: 328
  • Water flow rate, gpm: 450
  • Operating temperature, oF: 60 to 120
  • Operating pressure, psig: 40
  • Oxygen content of in stripping gas, ppm: 70
  • Dissolved oxygen content in canal water, mg/L: 9
  • Dissolved oxygen removal: > 90%

Click on the link below to download literature about this application.

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Topics: particulate control, Scrubbers, Incinerator Scrubber, quenchers, Packed Bed Absorbers, Packed Bed Scrubbers, Wet Scrubbers

Auto Shredder RTO and Acid Gas Scrubber

Posted by Andy Bartocci on Tue, Jun 02, 2020 @ 08:30 AM

The metal recycling industry provides tremendous societal benefit by preserving natural resources and reducing greenhouse gases. Metal recycling entails pulverizing and shredding vehicles and appliances into smaller pieces to facilitate melting processes. Large mega shredders are often eAuto Shredder RTO Scrubber_Browsenclosed to capture process emissions. Volatile organic compounds (VOCs) and other hazardous air pollutants (HAPs) are released during shredding, including small amounts of halogenated compounds.

In recent years, some state and regional regulatory agencies have begun requiring Best Available Control Technology (BACT) to treat shredder exhaust gases for VOCs and other HAPs. One facility had a need to treat a large volumetric flow rate from their shredder enclosure. The equipment must meet stringent performance limits, be reliable, and capable of 24/7 operation.

Envitech partnered with Process Combustion Corporation (PCC) to provide a comprehensive BACT solution. The partnership leverages PCC’s 50 years of experience engineering thermal systems for air pollution control with Envitech’s wet scrubber expertise. PCC provided a regenerative thermal oxidizer (RTO) for VOC control and interconnect ductwork and incorporated an Envitech packed bed acid gas scrubber system. The scrubber scope of supply includes two (2) equal trains consisting of a horizontal Hastelloy C276 quencher, 13 foot diameter fiberglass packed bed absorber, instruments, pre-assembled recirculation pump skid with redundant pumps, and stack.

The horizontal quenchers ensure the gas is fully saturated across all operating conditions and simplifies ductwork between the RTO and scrubber.

CFD modeling minimizes pressure drop and prevents re-entrainment.

The system will be installed and operational in 2021. Guarantees are provided to meet the below design conditions. The combined PCC/Envitech process provides a reliable, comprehensive solution to meet the demands of a more stringent regulatory environment.

  • Gas flow rate: 140,000 acfm
  • VOC destruction: > 98%
  • Acid gas removal (HF and HCl): > 99.5%
Click on the link below to download literature about this application.

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Topics: particulate control, Scrubbers, Incinerator Scrubber, quenchers, Packed Bed Absorbers, Packed Bed Scrubbers, Wet Scrubbers