Boiler Blog | Nationwide Boiler Inc.

Be sure to read Part I of this series to learn about emissions requirements in the SCAQMD.

In the last edition of Boiler Blog 101, we discussed air permitting rules and regulations in the South Coast Air Quality Management District (SCAQMD). In part II, we will cover the basics of air permitting for boilers in another California district that leads the country in air pollution control; the San Joaquin Valley Air Pollution Control District (SJVAPCD).

The SJVAPCD was founded in 1991 with a mission to improve the health and quality of life for all Valley residents through efficient, effective and entrepreneurial air quality management strategies. The SJVAPCD is made up of eight counties in the Central Valley of California; San Joaquin, Stanislaus, Merced, Madera, Fresno, Kings, Tulare, and Kern.

The rules that have been set forth specifically for boilers, steam generators, and process heaters are outlined below:

Starting at the beginning of 2019, the SJVAPCD implemented a new rule titled, Best Available Control Technology (BACT). This rule requires that all new permits meet the lowest NOx limits that have been achieved, regardless of what is mandated. In addition, due to Assembly Bill 617, boiler owners in the SJVAPCD are mandated to meet Best Available Retrofit Control Technology (BARCT) for any existing equipment retrofits. This means that when your boiler needs to be upgraded or replaced, it must meet more stringent NOx limits, which can be as low as 7 ppm.

These rules can be overwhelming, which is why Nationwide Boiler’s AQMD experts are capable and ready to assist you with the permitting process needed for your facility. Furthermore, we can help you reduce NOx to comply with your air emissions regulations. Nationwide Boiler’s CataStak™ SCR system is proven to reduce NOx levels to as low as 2.5 ppm. Contact us today for more details.

Combustion equipment safety is essential for the daily operation of facilities and safety of plant personnel. Safety protocols and mechanisms in industrial plants have improved drastically in the last century, but incidents still occur far too frequently. Because boiler systems are inherently dangerous, safety must be factored into the design of not just the boiler, but also the burner, combustion control, and the overall operation of the system.

The burner management system (BMS) is just one of many safety devices built into a boiler system, designed to control the combustion process from beginning to end in a safe and reliable manner. It monitors high and low gas pressure, the combustion air fan, combustion air, and water levels, in addition to monitoring safety devices and controlling the sequence of lighting the burner. If any issues arise related to pressure or water level, it will initiate closure of the shut-off valves. To automate these processes, PLC-based controls are often used as a BMS. PLC based BMS gives you much more flexibility, the ability to use analog input signals as limits, limit voting and the versatility to have almost unlimited safety limits.

A Programmable Logic Controller (PLC) is a robust computer utilized for industrial automation. Although a PLC doesn’t physically look like a typical computer, it incorporates the very same technology seen in computers and smart devices that we use every day. The PLC receives information from connected sensors or input devices, processes the data, and triggers outputs based on pre-programmed parameters. It consists of a power supply, a CPU (central processing unit), input and output cards, and communication cards. A programming device (often a laptop computer) is utilized for writing programs into the PLC and HMI (human machine interface) which provides a visual model of the system as a whole.

Compared to traditional technologies, a PLC-based system is easier to troubleshoot, more reliable, more cost-effective, and much more versatile. In addition, PLC-based controls provide added levels of safety for the burner management system and overall operation of your boiler. PLCs are built in compliance with NFPA 85 and SIL2 requirements at minimum and can be configured to meet SIL3 standards as well. Therefore, we are seeing boiler control panels being built or updated to PLC-based systems more than ever.

Pacific Combustion Engineering has extensive knowledge and experience in the design, build, and programming of PLC-based combustion control systems. If you are in the market for an upgrade or brand-new panel that incorporates PLC, give us a call and we will design a system that fits your unique process needs.

Routine boiler maintenance is imperative not only for safety, but also to sustain efficiency and reliability of your system. Being proactive rather than reactive is likely to increase the longevity of your boiler as well as help prevent incidents that can result in injuries, damage, or worse. Incorporating routine maintenance into your facilities day-to-day operations will prove its worth with a great deal of short- and long-term benefits.

There are certain maintenance tasks that should be performed daily, and others that should be performed periodically. Below we have provided a list of best practices to follow when putting together your routine boiler maintenance plan.

On a daily basis, you should track and keep a log of the following items:

• Boiler pressure and temperature
• Stack temperature, to determine operational efficiency (a well-tuned boiler should have a stack temperature range of 50 – 100 degrees above the steam or water temperature)
• Gas pressure to the regulator, as well as downstream from it
• Water quality and pH levels, to ensure you are meeting the recommended levels

Blowdown of the boiler (bottom blow) and water column should also be performed on a daily basis. In addition, you should observe boiler and auxiliary equipment daily to ensure proper operation and that there is no damage, leaks, or unusual behavior. 

On a weekly to monthly basis, it’s important to conduct additional visual inspections and observe the operation of certain components for areas that may need to be addressed. This includes:

• Gauge glass
• Fuel supply valves
• Operating and modulating controls, water level controls
• Flame scanner & burner flame pattern
• High- and low-pressure switches, combustion air proving switch
• Indicating lights and alarms

When it comes to the burner, you should inspect the valves, pilot tube, and diffuser thoroughly for any signs of wear that might call for a repair. Also, be sure to observe the entirety of the boiler system for potential hot spots (an indicator of deteriorated refractory) and again, be sure to keep an eye out for any leaks of fuel, water, or flue gas.

Lastly, there are certain items that should be performed on a semi-annual to annual basis. Many of the tasks below can be checked off during the annual inspection, when the boiler is taken offline:

• Open access doors and inspect the fireside of the boiler
• Inspect boiler and tubes for evidence of corrosion; clean tubes and tube sheets thoroughly
• Examine the refractory for large cracks (greater than 1/8”) and patch as necessary
• Conduct safety tests on the gas valves
• Review all electrical connections for tightness, signs of wiring wear
• Check pump alignment on all base-mount pumps

This is also a good time to fully inspect the auxiliaries that provide fuel, air, water, and chemicals to the boiler. In addition, combustion should be reset periodically with the use of a combustion analyzer, for accurate readings of NOx, CO, and O2.

While the guidelines above provide a good baseline of tasks to perform when it comes to routine maintenance, be sure to consider the boiler manufacturer’s recommendations as well.  

Within the RECLAIM standards, Rule 1146 outlines specific guidelines for boilers, steam generators, and process heaters that have a heat input of 5 mmBtu/hr or greater, that are utilized in all industrial, institutional, and commercial operations. This rule has changed several times, and at the end of 2018, another revision to the rule was adopted. All Group 1 units (>/= 75MMBTu/hr) as well as Group II units (20 - 75 MMBTu/hr) with an existing permit limit greater than 2 ppm must comply with a 5 ppm NOx limit. In addition, facilities that qualify must be in compliance by 2022 – 2023. The table below outlines all equipment and current limits based on category and heat input.

If your facility falls into the RECLAIM bubble, Nationwide Boiler can assist in bringing your stationary equipment up to current standards to comply with the latest rules and regulations. Our CataStak™ SCR system is proven to reduce NOx emissions to as low as 2.5 ppm on boilers, fired heaters, and other demanding applications. Imagine what we can do for your facility to get you in compliance with RECLAIM!

Stay tuned for part 2, where we will outline specific rules and regulations within the SJVAPCD.