Low NOx Boilers | Low Emission Boilers & Equipment

Author: Alice

Dec. 16, 2024

Low NOx Boilers | Low Emission Boilers & Equipment

As a result of the EPA&#;s Clean Air Act, many state and federal environmental regulations require increasingly stringent lower NOx emissions compliance for manufacturing facilities, chemical plants, refineries, and industrial plants dependent on production processes that produce NOx, CO and other VOCs. These facilities are faced with meeting or exceeding low NOx (30 ppm) and even ultralow NOx (<9 ppm) emission requirements, which frequently requires boiler system equipment upgrades or replacement.

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MORE FROM OUR BLOG Is low NOx a low priority?

NOx Formation

Thermal NOx is a byproduct of the combustion process that is formed by industrial boilers and process heaters when burning natural gas (and other fuel gases with no bound nitrogen), where high flame temperatures cause nitrogen molecules from the combustion air to combine with oxygen to form nitric oxide.

Low NOx Boilers & Boiler Equipment

Low NOx boilers provide improved energy efficiency and lower emissions of nitrous oxides. NO and NO2 are toxic atmospheric gases. Our Low NOx boilers combine energy efficiency with NOx-related upgrades and reduce nitrous oxides, save energy and reduce greenhouse gases. Low NOx boilers can utilize several design and equipment solutions to significantly reduce overall nitrogen oxide (NOx) emissions and reach levels under 30 ppm:

  • Low NOx Burners &#; Low NOx boiler burners are designed to maintain stable combustion at lower flame temperatures and offer good turndown. Well-designed low NOx burners operate using a minimum excess air requirement (and leave very little unburned fuel), resulting increased combustion efficiency - more energy is available for the load, as less heat from the combustion process is needed to heat combustion air.
  • Flue Gas Recirculation (FGR) &#; FGR meters a percentage of flue gas, reintroducing it back into the combustion air supply, increasing or decreasing the percentage of FGR based on the amount of reduction in NOx required.
  • High Efficiency Boilers &#; The term &#;boiler efficiency&#; refers to thermal efficiency (fuel-to-steam efficiency) of the boiler&#;s heat exchanger, taking into account radiation and convection losses. High efficiency boilers maximize the transfer of heat from the combustion process to the water or steam in the boiler, keeping fuel requirements lower as a result of optimized performance.
  • Advanced Air/Fuel Controls - One of the factors influencing NOx formation in a boiler is the excess air level. Altering the fuel/air ratio to improve fuel/air distribution and mixing, and limiting the amount of excess O2 entering a flame via oxygen trim controls can help reduce NOx emissions. Advanced controls can deliver extremely precise air to fuel ratio control with excellent repeatability.

Upgrading or Replacing Equipment

Whether you&#;re looking for a new Low NOx boiler or a retrofit option for an older system, IB&M has the expertise and materials to make this happen with ease. We can help you evaluate the costs associated with purchasing new equipment vs upgrading in order to achieve fuel savings, reduce operating costs, and meet compliance requirements. Deciding the best route to NOx reduction is largely based on:

If you are looking for more details, kindly visit Partedon Group.

  • Boiler Efficiency & Performance - As stated above, boiler efficiency and the effective transfer of heat is influenced by a number of factors like boiler size and load characteristics, air to fuel ratio burner control accuracy, programmable boiler controls and excess air trim management, low emissions burner technology, turndown, type of fuel, and emission requirements.
  • Maintenance Costs - Add up the costs of major maintenance, emergency maintenance and downtime due to equipment age, burner and refractory problems, along with the challenge of parts availability and expense, and time spent keeping units on-line, etc. to better understand the true cost of ownership.
  • Fuel Costs - Fuel typically represents the largest expense associated with running a boiler, and can impact boiler efficiency 2% or more in fuels like fuel oil and natural gas which have varying hydrogen content and related water vapor losses.

Maintain peak performance

A Low Nox Boiler System does not have to mean low performance. Upgrading to a Low NOx boiler system lowers your carbon footprint by reducing greenhouse gases, ensuring you meet all state and federal regulations. Numerous states offer incentives for plants converting to Low NOx boilers.

Our boiler systems feature the latest in emission-reduction technology such as microprocessor-based gas and air pre-mix, thermal reduction, and flue gas recirculation. The result is cleaner, more efficient fuel usage and significant operating cost savings.

Industrial Boiler & Mechanical can help you with finding a new or rental low NOx boiler or upgrading existing burners and equipment to meet EPA compliance regulations.

Nitrogen Blanket on Boiler



Photos follow.

Bill of materials:
Brass quick connection for 1/4" NPT air line
300 PSI steam rated globe valve
300 PSI steam rated lift check valve
Schedule 80 1/4" close nipples & elbows
Flexible hose, length to suit
Non-flammable gas regulator from tank pressure to 20 PSI
Propane / LP gas pressure regulator,factory set @ 11 inches of water
Technical grade nitrogen gas cylinder from welding / industrial gases supplier
Chain and hardware to safely support and secure nitrogen cylinder
Warning signs where bodily entry can be made: Inert Gas Atmosphere, ventilate and check atmosphere prior to entry.

Here is how it works:
When a boiler is stored wet, oxygen from the air dissolves in the cold water. This oxygen causes rusting and pitting of the boiler steel.
A steaming boiler that has venting steam, has dissolved oxygen levels down in the Parts Per Billion range.
To prevent oxygen damage when cold, apply the nitrogen when the boiler is cooling down from steaming, but still has a few PSI of steam pressure.

Instead of drawing a vacuum and drawing in air as the steam head condenses, the boiler draws in nitrogen through the check valve.

The manual valve connected above the water line of the boiler is opened. The check valve prevents steam escaping.

The nitrogen cylinder valve is opened. This supplies 11 in. of water pressure to the female end of the quick connector at the end of the hose.
Use a dab of silicone grease on the " O " ring seal to prevent damage to the seal.
Hang the hose so that there are no water traps, and any condensation in the hose drains to the boiler.
It is imperative that no water traps accumulate in the line.
With only 11 inches of pressure supplied, slightly less than 1/2 PSI, flow could be blocked by accumulated condensate water traps.

Maintain the nitrogen pressure until the boiler cools below 120 F, about the temperature you can hold your hand on it.

Assuming that there are leaks at whistles, safety valve and valve stem packings, and the of economy of nitrogen, the supply can be valved-off at this point.

It is recommended that the nitrogen be valved-in to purge the boiler for a few minutes weekly.
If your boiler is pressure tight, and can hold the nitrogen, this step is not necessary, but the pressure should be checked.
A boiler can be held in this layup indefinitely, assuming the water pH is in the 10 to 11 range and no air enters.

If you choose to use a chemical oxygen scavenger, such as sodium sulfite, and dissolved phosphate chemistry,
it is necessary to circulate the water and check the chemistry every 30 days.

Note: The use of a nitrogen blanket will not prevent freezing of the boiler water and related physical damage.
We all know this, but the Legal Department insisted I make this Idiot Proof !

To clear the nitrogen blanket, simply shut or check shut, the supply and boiler connection valves and remove the quick connection hose. The boiler is ready to fire.

At the request of a fellow 'Stakker, here is a setup for applying nitrogen to a boiler to prevent oxygen pitting and rusting.Photos follow.Bill of materials:Brass quick connection for 1/4" NPT air line300 PSI steam rated globe valve300 PSI steam rated lift check valveSchedule 80 1/4" close nipples & elbowsFlexible hose, length to suitNon-flammable gas regulator from tank pressure to 20 PSIPropane / LP gas pressure regulator,factory set @ 11 inches of waterTechnical grade nitrogen gas cylinder from welding / industrial gases supplierChain and hardware to safely support and secure nitrogen cylinderWarning signs where bodily entry can be made: Inert Gas Atmosphere, ventilate and check atmosphere prior to entry.Here is how it works:When a boiler is stored wet, oxygen from the air dissolves in the cold water. This oxygen causes rusting and pitting of the boiler steel.A steaming boiler that has venting steam, has dissolved oxygen levels down in the Parts Per Billion range.To prevent oxygen damage when cold, apply the nitrogen when the boiler is cooling down from steaming, but still has a few PSI of steam pressure.Instead of drawing a vacuum and drawing in air as the steam head condenses, the boiler draws in nitrogen through the check valve.The manual valve connected above the water line of the boiler is opened. The check valve prevents steam escaping.The nitrogen cylinder valve is opened. This supplies 11 in. of water pressure to the female end of the quick connector at the end of the hose.Use a dab of silicone grease on the " O " ring seal to prevent damage to the seal.Hang the hose so that there are no water traps, and any condensation in the hose drains to the boiler.It is imperative that no water traps accumulate in the line.With only 11 inches of pressure supplied, slightly less than 1/2 PSI, flow could be blocked by accumulated condensate water traps.Maintain the nitrogen pressure until the boiler cools below 120 F, about the temperature you can hold your hand on it.Assuming that there are leaks at whistles, safety valve and valve stem packings, and the of economy of nitrogen, the supply can be valved-off at this point.It is recommended that the nitrogen be valved-in to purge the boiler for a few minutes weekly.If your boiler is pressure tight, and can hold the nitrogen, this step is not necessary, but the pressure should be checked.A boiler can be held in this layup indefinitely, assuming the water pH is in the 10 to 11 range and no air enters.If you choose to use a chemical oxygen scavenger, such as sodium sulfite, and dissolved phosphate chemistry,it is necessary to circulate the water and check the chemistry every 30 days.Note: The use of a nitrogen blanket will not prevent freezing of the boiler water and related physical damage.We all know this, but the Legal Department insisted I make this Idiot Proof !To clear the nitrogen blanket, simply shut or check shut, the supply and boiler connection valves and remove the quick connection hose. The boiler is ready to fire.

If you want to learn more, please visit our website Low Nitrogen Steam Boiler(ja,th,tr).

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