Code of Practice to reduce emissions of PM2.5 and VOCs from iron, steel and ilmenite sector: chapter 3


3.0 Recommended Best Practices

This section presents recommended methods and measures to mitigate fugitive TPM and VOC emissions. These recommendations were derived from regulatory and non- regulatory best environmental practices, published by various agencies, organizations and jurisdictions. Each of these recommendations should be applied where and when appropriate and practicable based on the particular circumstances of each facility.

3.1 General Recommendations

Prevention and Control of Fugitive Air Emissions - Recommendation R01 (TPM and VOC)

Potential sources of fugitive emissions should be identified, prevented and controlled through the use of appropriate mitigative measures. These sources may include roads (paved or unpaved), storage piles, materials conveyance systems, secondary material storage and waste disposal piles, leaks from pipes or storage tanks, and fugitive process emissions from buildings.

To prevent fugitive emissions, documented procedures should be developed and facilities should implement good housekeeping and best environmental practices. These would, for example, include hoods and/or enclosure of process equipment, use of covered or enclosed conveyors and transfer points, and implementation of Leak Detection and Repair (LDAR) programs. Other emission control techniques include raw material storage pile optimum design and best environmental practices for bulk-material storage piles, such as covering of storage piles and application of crusting materials to bulk- material storage piles. Paving of yards and/or application of environmentally friendly dust-suppression material tounpaved roadways, scheduled washing of mobile equipment, and routing of runoff water to settling ponds could also be beneficial for minimizing fugitive emissions. The evaluation of conformance with operating specifications for each type of equipment may also help in minimizing fugitive emissions.

Collection and Control of Process Air Emissions - Recommendation R02 (TPM and VOC)

Emission control systems, including handling facilities for collected material, should be adequately sized, designed, constructed, operated and maintained to contain, control andminimize pollutant releases to ambient air from plant processes.

Emission control equipment should be designed on the basis of sound engineering considerations and should be able to maintain control of releasesto the ambient air from all operational sources, and at different operational conditions including minimizing the effects of operational upset events.

Best emission control technologies and techniques should be researched and adopted on a site-specific basis to minimize emissions.

Minimization of Fugitive Air Emissions - Recommendation R03 (TPM and VOC)

Operating practices that minimize fugitive emissions from those operations that are not amenable to enclosure or hooding should be developed and implemented.

Monitoring and Reporting for Emission Control Systems - Recommendation R04 (TPM and VOC)

Control equipment should be monitored and inspected regularly in order to maintain proper collection of releases, therefore reducing fugitive emissions. Documentation of procedures for the monitoring and inspecting of emission control equipment should be developed. These procedures should include documenting the collection efficiencies of control equipment.

3.2 Materials Handling, Movement and Storage

Materials Handling - Recommendation R05 (TPM)

  1. Adjust heights of loading/unloading/stockpiling equipment to minimize drop height.
  2. Monitor moisture content of raw materials, secondary materials, wastes and by-products. For example, spray water with equipment such as portable water cannons for mobile sources and water spray nozzles for stationary sources.
  3. Limit or restrict material handling based on wind conditions and visual inspections.

Materials Movement - Recommendation R06 (TPM)

  1. Spray water on the open conveyors and transfer points.
  2. Shroud conveyors/transfer points at critical points to avoid wind erosion on the material being transported.
  3. Limit vehicle speed on unpaved roads using signs and training. d)  Pave yards and roads.
  4. Wash vehicles.
  5. Spray water or dust suppressants on the road surfaces.
  6. Limit or restrict access to unnecessary roadways.
  7. Maintain roads that have been damaged through usage over time.
  8. Remove dust accumulated on the paved roads/areas using industrial sweepers.
  9. Grow vegetation on open areas that are not used for traffic or materials storage.
  10. Install wind breaks (e.g., fences, trees) to inhibit transport of dust.
  11. Minimize egress of fugitive emissions through doors and openings as much as possible. Keep doors and other building openings closed where sources of dust operate.

Materials Storage - Recommendation R07 (TPM)

  1. Set stockpile configuration in order to minimize fugitive dust emissions due to wind erosion:
    • Use large piles rather than several small piles, in order to minimize total surface area.
    • In case of piles with wide range of size distribution, dispose finer materials in the base and coarser materials in the top of the stockpiles.
    • Set pile orientation based on prevailing wind direction.
    • Include wind breaks in the pile set-up.
    • Minimize pile ridges.
  2. Spray water or other dust suppressant on stockpile surface.
  3. Seal stockpiles with coarse granular material or dust suppressants (e.g., crusting agents).
  4. Limit or restrict reclaiming operations based on wind conditions and visual observation.
  5. Cover stockpile.

Liquid Storage - Recommendation R08 (VOC)

The recommendations in the Canadian Council of Ministers of the Environment’s Environmental Guidelines for Controlling Emissions of Volatile Organic Compounds from Aboveground Storage TanksFootnote2 should be applied to light oil, wash oil, crude liquor, liquid fuels, petroleum products, solvents and tar storage tanks.

Liquid Storage - Recommendation R09 (VOC)

  1. Liquid storage and containment facilities should be designed and constructed to meet the requirements of the appropriate standards, regulations and guidelines of the pertinent regulatory agency. Each facility should develop, document and implement a storage tank management program. This recommendation applies toliquid fuels, acids, petroleum products, solvents and other liquids that are combustible or potentially harmful tothe environment.
  2. Vapours from loading or transferring high-vapour pressure liquids--e.g., benzole and coal oils--should be vented to abatement equipment or returned to the storage tank. Tank and drum lids should always be closed.
  3. Storage tanks of volatile liquids venting directly to air should have pressure/vacuum release valves to minimize vapour losses. Vacuum pumps should vent to process or collection equipment.
  4. Tank paint with low solar absorbency, temperature control tank insulation and inventory management should be used (together or in any combination with other techniques) to reduce losses from storage tanks at atmospheric pressure.
  5. Storage tanks should include secondary seals and a floating roof to reduce VOC emissions.
  6. The loading, unloading, handling and storage of liquid fuels and bulk chemicals should be carried out so as to prevent leakage and spillage.
  7. Inert gas blanketing systems should be employed to reduce emissions from storage and handling system.

3.3 Cokemaking

Recovery Coke Ovens, Charging Operations - Recommendation R10 (TPM and VOC)

Develop, document and implement procedures for:

  1. The nature and frequency of equipment inspections.
  2. Replacement or repair of emission control equipment and the method used to audit the effectiveness of the inspection and repair program.
  3. Enclosure and/or hooding with emission controls of the charging of coal. d)  Filling of larry car hoppers.
  4. Alignment of larry cars over the oven to be charged.
  5. Filling of the ovens (e.g., procedures for staged or sequential charging). g)  Levelling of coal inthe ovens.
  6. The inspection and cleaning of offtake systems (including standpipes, standpipe caps, goosenecks, dampers and mains), oven roofs, charging holes, topside port lids, steam supply system and liquor sprays.

Coke Oven Doors - Recommendation R11 (TPM and VOC)

Develop, document and implement procedures for:

  1. A program for the inspection, maintenance, repair and replacement of coke oven doors, jambs, seals and any other equipment used to control emissions from coke oven doors.
  2. The method to be used to evaluate conformance with operating specifications for eachtype of equipment.
  3. The methods to be used to audit the effectiveness of the inspection and repair program.
  4. Identifying leaks that indicate a failure of the emissions control technology.
  5. A clearly defined chain of command for communicating information on leaks and procedures for corrective action.
  6. Cleaning sealing surfaces of doors and jambs that include the identification of equipment that will be used and a specified schedule or frequency for the cleaning of the sealing surfaces.
  7. The use of supplemental gasketing and luting materials, and hand luting. h)  Maintaining spare coke oven doors and jambs on site.
  8. Monitoring and controlling back pressure in the collecting main, including corrective action if pressure control problems occur.
  9. Improved coke oven door sealing.

Topside Port Lids, Offtake Systems, Coke Wet Quenching - Recommendation R12 (TPM and VOC)

Develop, document and implement procedures for:

  1. The inspection, maintenance and replacement or repair of topside port lids and portlid mating and sealing surfaces.
  2. The frequency of inspections.
  3. The evaluation of conformance with operating specifications for each type of equipment.
  4. An audit to determine the effectiveness of the inspection and repair programs. e)  The identification, management and repair of leaks from the offtake system.

Coke Oven Battery Stacks - Recommendation R13 (TPM and VOC)

Develop, document and implement procedures for:

  1. Frequency and method of recording underfiring gas parameters and battery operating temperatures.
  2. Frequency and method for inspecting flues, burners, nozzles, mixing and injection systems.
  3. A preventive maintenance program to address results of inspection findings. d)  A method for the investigation and remedy of the cause(s) of:
    • Sudden increase in opacity exceeding applicable opacity emission standards.
    • Malfunction or upset of the combustion control system.

Coke Pushing and Transfer to Quench Station -Recommendation R14 (TPM and VOC)

Develop, document and implement procedures for:

  1. Minimizing the occurrence and severity of “green” pushes.
  2. Dampering off ovens before a push.
  3. The inspection and replacement or repair of pushing emission control system components.
  4. The frequency of inspections.
  5. An audit to determine the effectiveness of the inspection and repair program.
  6. Minimizing emissions from the transfer of hot coke to the quench station.
  7. The prevention of pushing an oven out of sequence, pushing prematurely, and undercharging or overcharging.
  8. Identifying pushing emissions that indicate occurrences of incomplete coking or a failure of the emissions control technology to function properly, which include a clearly defined chain of command for communicating information on such occurrences and procedures for corrective action.

Oven Doors, Lids and Ascension Pipes (stand pipes) -Recommendation R15 (TPM and VOC)

Develop, document and implement procedures for:

  1. Regular maintenance of doors in a repair bay to prevent deterioration of seals and correct any mechanical damage.
  2. Charge hole rims and lids to prevent leakage.
  3. The use of effective sealants.
  4. The use of water-sealed caps for ascension pipes and good maintenance of the caps.

Bypass/Bleeder and Flare Stacks (coke oven gas flaring) - Recommendation R16 (TPM AND VOC)

Develop, document and implement procedures for:

  1. The flaring of coke oven gas.
  2. The inspection, repair and replacement of flare system components.
  3. The evaluation of conformance with operating specifications of the flare system.
  4. The minimization of the volume of gas flared.
  5. Optimizing combustion efficiency to minimize visible emissions.
  6. Reporting and correcting malfunctions of the flare system.

3.4 Coke By-product Plant

Coke By-Product Plant - Recommendation R17 (VOC)

The recommendations in the Canadian Council of Ministers of the Environment’s Environmental Code of Practice for the Measurement and Control of Fugitive VOC Emissions from Equipment LeaksFootnote3 should be followed.

Benzene Transfer Operations - Recommendation R18 (VOC)

A vapour collection system should be used to contain benzene vapours during the transfer of benzene-containing liquids to tank trucks or rail cars.

Open Trenches and Sumps - Recommendation R19 (VOC)

Process trenches and sumps associated with coke oven gas, crude liquor, light oil, wash oil and tar handling should be enclosed and the vapours collected for treatment.

Containment of Process Pumps and Tanks - Recommendation R20 (VOC)

Process pumps and tanks should be installed on impervious pads with containment dikes and drainage to wastewater treatment facilities to contain spills.

Equipment LeaksFootnote4 - Recommendation R21 (VOC)

  1. Compressors should be equipped with seal systems including barrier fluid system to prevent leakages. Barrier fluid systems require seal failure sensors, and should be checked daily or equipped with an audible alarm.
  2. Pressure relief devices in gas/vapour service should operate with no detectable emissions, except during pressure releases. Devices should be returned to a state of no detectable releases within five days of release, and conditions monitored.
  3. Each sampling connection system should be equipped with a closed-purge system or closed-vent system. The purged process fluid should be returned to the process line, or collected and recycled, or captured and transported to a control device.
  4. Open-ended valves and lines should be equipped with a cap, blind flange, plug or second valve.
  5. Leaks from pumps, compressors, valves, pressure relief devices, connectors, closed-vent systems and control devices should be detected using appropriate methods. Once detected, leaks should be repaired.
  6. Product accumulator vessels should be equipped with closed-vent systems capable of capturing and transporting leakages to a control device.
  7. Delay of repair of equipment for which leaks have been detected could be allowed if the repair is technically infeasible without process unit shutdown.
  8. Vapour recovery systems and enclosed combustion devices should recover organic vapours with an efficiency of 95% or to an exit concentration of 20 parts per million by volume. Closed-vent systems should operate with no detectable emissions; otherwise, repair is required.

3.5 Ironmaking

Blast Furnace Ironmaking - Recommendation R22 (TPM and VOC)

  1. Enclosure and/or hooding with emission controls of the blast furnace tapping operations and discharge of molten metal and slag.
  2. Cover ladles containing molten metal.
  3. Maximize capture efficiencies by having tapping and discharge operations located within a controlled area of the facility.
  4. Cast house fugitive emissions should be minimized by covering the runners and evacuation points (tap-holes, runners, skimmers, ladle charging and by using tar-free runner linings).

Direct Reduction Ironmaking - Recommendation R23 (TPM)

  1. Enclosure and/or hooding with emission controls of the shaft furnace operations anddischarge of iron.
  2. Maximize capture efficiencies by having discharge operations located within a controlled area of the facility.

Ilmenite Reduction Furnace - Recommendation R24 (TPM)

  1. Enclosure and/or hooding with emission controls of the charging and tapping operations.
  2. Maximize capture efficiencies by having tapping and discharge operations located within a controlled area of the facility.
  3. Cover ladles containing molten metal.
  4. Continual improvement of the baghouse operation and collection efficiency. e)  Enclosure of the filter dust collection and discharge.

3.6 Steelmaking

Basic Oxygen Furnace Steelmaking - Recommendation R25 (TPM and VOC)

  1. Enclosure and/or hooding with emission controls of the molten metal transfer, charging and tapping operations.
  2. Maximize capture efficiencies by having tapping and discharge operations located within a controlled area of the facility.
  3. Cover ladles containing molten metal.
  4. Scrap Management Program for the prevention or minimization of contaminants in steel scrap and other feed materials:
    • Non-ferrous contaminants should be minimized to the extent practicable.
    • All grades of scrap should be free of excessive dirt, oil and grease.

Electric Arc Furnace Steelmaking - Recommendation R26 (TPM and VOC)

  1. Enclosure and/or hooding with emission controls of the charging and tapping operations.
  2. Maximize capture efficiencies by having tapping and discharge operations located within a controlled area of the facility.
  3. Cover ladles containing molten metal.
  4. Continual improvement of the baghouse operation and collection efficiency.
  5. Enclosure of the filter dust collection and discharge.
  6. Scrap Management Program for the prevention or minimization of contaminants in steel scrap and other feed materials:
    • Non-ferrous contaminants should be minimized to the extent practicable.
    • All grades of scrap should be free of excessive dirt, oil and grease.

3.7 Steel Finishing

Continuous Casting - Recommendation R27 (TPM)

  1. Enclosure and/or hooding with emission controls of the area where the tundish is filled.
  2. Maximize capture efficiencies by having tapping and discharge operations located within a controlled area of the facility.
  3. Cover ladles containing molten metal.

Hot Rolling and Cold Forming - Recommendation R28 (TPM and VOC)

  1. Enclosure and/or hooding with emission controls throughout the process (cold forming only).
  2. Design and installation of a hooding system and oil mist emission collection system to collect and capture rolling oil mists (cold forming only).
  3. Collection, interception and disposal of oil spills and leakages.
  4. Implementation of an environmentally responsible oil disposal system. e)  Minimizing oil inputs is also part of best environmental practices.

Coating - Recommendation R29 (VOC)

  1. Use of low-VOC products.
  2. Consider local hooding and wet scrubber for interception and treatment of fugitive VOC emissions during application by brushing, rolling, spraying or immersion of organic compounds in the form of powders, paints and liquids.

3.8 Combustion, Boilers and Reheat Furnaces

Combustion, Boilers and Reheat Furnaces - Recommendation R30 (VOC)

Each facility should develop and implement best environmental practices for minimization of VOC emissions with a preventive maintenance program, including documented methods of investigation and repair, and development of a protocol forthe calculation of the VOC emissions. The primary control method for VOC emissions from boilers and reheat furnaces is the optimization of combustion efficiency and the use of natural gaswhere by-product fuel is not available.

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