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The PCC-IV loop controller is the next generation of Preferred’s loop controllers AND upgraded technology for the entire industry. The PCC-IV is more flexible, has extensive memory, and not only replaces the Preferred PCC-III, but also can replace the Siemens Moore 352 and 353, obsolete and no longer supported starting October 2017.

Preferred Utilities’s controls are just that- preferred. Consider a case study of a longtime PCC controls customer:

Preferred Utilities has been supporting this facility in New York since 1988 with our PCC II and III loop controllers. This site installed one PCC-IV and is now considering this next generation of upgrade, the PCC-IV, in their plant with four (4) 50kpph boilers, each with steam, gas, and oil flow meters.

In 1988, the facility installed 16 PCC-IIs and 5 control panels, plus field instruments for a burner/controls upgrade. Almost 10 years later in 1997, they updated the system with the purchase and installation of 17 PCC-IIIs. In 2002, they decided to upgrade again and add O2 trim. Satisfied with the Preferred product, they installed 21 of the PCC-III units.

Now, in 2017, the plant installed a PCC-IV in parallel with one of the PCC-III controls to observe the performance and is considering upgrading the rest of the PCC-II and PCC-III controls. With the auto-converting functionality of the PCC-IV, the existing PCC-III programs can be re-used without modification and re-programming.

Preferred Utilities is pleased to offer generations of quality products that age gracefully and come with a pledge of full service support and solutions for upgrades in the future.

PCC-IV Loop Controller Front

PCC-IV Loop Controller internal

 

 

 

A New Jersey paper mill came to Preferred Utilities recently needing a quote for a new burner for their 1961 Preferred Utilities Unit Steam Generator. What is wrong with their existing Preferred burner? Nothing. The plant is being forced to convert from No. 6 heavy fuel oil to natural gas.

Will their next burner last 56+ years? Maybe. It depends on who they buy it from.

Note, Preferred still had the documentation on the existing burner and boiler. But we had to go to 49 year Preferred veteran engineer Ricky Erickson to find it.

This plant needs a Low NOx burner that meets the emissions regulations in New Jersey. Preferred designs and builds burners that can meet the strictest regulations, and provides configurable NOx settings, “future-proofing” them against lower emissions requirements that states may adopt in the coming years.

Built for the environment. Built to last.

 

 

Last summer a facility in Texas spilled 3,500 gallons of diesel fuel intended for one of their emergency generators. The fuel was pushed up through a day tank vent, ran across their parking lot, and into a pond adjacent to their property. The clean-up team recovered about 2,100 gallons of fuel out of the pond, but at a cost of about $300,000.

I was called to the site two weeks after the spill and took these pictures of the pond. It’s amazing how resilient nature can be in Texas. The only damage I could see to the pond was browned grass below the waterline. Now, ten months later, the pond appears to have fully recovered.

 

The generator fueling system for this facility was installed in 2013. From an inspection of the day tanks, all the instrumentation and safety devices met the required NFPA and local fire codes. However, I did not recognize the systems integrator who did the PLC controls. I suspected there was an error in the PLC program exacerbated by a system design that didn’t anticipate something going wrong.

 

The facility owner brought in a couple of sharp corporate engineers to autopsy the existing controls. They found errors in the PLC programming logic. A level sensor failed, showing a low fuel level in the day tank, so the PLC controls energized supply pumps to re-fill the day tank from the main storage tank. With the level sensor stuck, the PLC controls ignored all the other instrumentation indicating the tank was full, continued pumping fuel, and quickly overfilled the tank. The facility engineers thought the system started pumping fuel at about midnight. Facility staff coming on duty at 7 a.m. smelled diesel fuel, noticed the fuel on the ground, and shut off the pumps.

 

At first glance, the control sequences for diesel generator fueling systems are not terribly complicated, so local systems integrators are often hired to provide controls for fueling systems. However, to ensure fuel is always available to mission critical emergency generators, and fuel spills are prevented, the Preferred engineers—who specialize in the design of generator fueling systems—try to anticipate every likely failure mode:

 

–What happens if a level sensor gets stuck?

–What happens if an analog transmitter fails and produces 0 milliamps?

–What should the controls do if a pump fails to prove flow?

–What happens if there is a break in a fuel line, or a tank starts to leak?

–What happens if an operator manually energizes a fuel transfer pump and then goes home?

 

After supplying so many fueling systems over the years, all of these failures will happen. Regardless of a component failure or operator error, fuel spills are still unacceptable, and the generators still need fuel.

 

I did boiler controls for twenty years before learning how to design and commission fuel handling systems. NFPA boiler code dictates all the safety devices and sequences required to operate boilers. As a result, at least three separate devices must fail to run the water out of a boiler, or overpressure a boiler. NFPA code for fueling systems is much less specific. In fact, the fuel system that caused the spill at this facility didn’t violate any NFPA fuel handling codes.

 

In the end, this facility’s Preferred installer and consulting engineer commissioned the new Preferred fuel handling system controls. Commissioning is the process of simulating all the “What happens if…” scenarios described above and verifying the fuel system responds correctly to all imaginable upset conditions.

 

It’s the last thing we do on every fuel handling project.

David Eoff, BSME, MBA

Preferred Utilities, National Sales Manager

 

What happened the last time your house lost power? That email you were writing might have had to wait an extra half an hour, and your refrigerator might have warmed a few degrees. At most, ordinary power outages represent a minor annoyance to the home or office.

The situation is different at the massive data centers of the world. Amazon now sells over 600 items per second, and their systems are designed to accommodate up to 1,000,0000 transactions per second. At this scale, a 20 minute power outage at one of the data centers powering its store could cost Amazon millions of dollars in lost revenue.

To avoid this sort of catastrophe, the world’s big data centers strive to meet the Uptime Institute’s “Tier-Standards,” specifying various levels of guaranteed data processing availability, reliability, and redundancy. Meeting these standards requires avoiding single-points of failure — all components must have redundant backups.

One of the most critical components, of course, is the power supply system: without power, the flow of data grinds to a halt. Although massive data centers pull their power from the public electric grid, they must have redundant systems of backup power ready to go. Stored power in batteries is important, but the real backup system is the diesel generator.

Managing the reliability and redundancy of their generator systems is a significant challenge for data centers. It’s an unfortunate reality that components break and systems fail tests. At many data centers, the fuel system supplying the generator will have components from a legion of vendors, not one of whom will understand (or take responsibility for) the whole system. This can make troubleshooting routine systems failures a nightmare.

Working with a company that provides a fully integrated system is essential – from the fuel tanks and pump systems to the monitoring devices and control systems. Therefore if a problem arises, data centers have a single support call to make. A single source contact will understand how the pieces work together and can quickly solve problems. It’s the difference between working with a parts manufacturer with a few engineers on staff, and an engineering design firm that manufacturer’s the parts.

At Preferred Utilities we specialize in fuel systems—it’s what we do all day, every day—we pride ourselves on designing reliable systems that reduce the need for support calls in the first place. Data center engineering teams are generalists and great at looking at the big picture, so when it comes to fuel systems, they often aren’t able to immerse themselves in the details the way our engineers do. We know the code compliance specs, how to make sure the tank size is correct, and how to optimize virtually any scenario to help data centers at all Tier levels to keep the their fuel, power, and data flowing.

If your company or industry requires this kind of technical expertise, you can reach Preferred Utilities Manufacturing Corporation at (203)-743-6741. We are dedicated to your success. People. Products. Results.

 

RFO-headerDiscussions of sustainable energy don’t often include food flavorings. However, the same process that creates liquid smoke—the stuff you can buy at the grocery store to add a smoky flavor to just about anything—can produce liquid wood, a very environmentally friendly fuel.

You may not have heard of liquid wood because, until very recently, it was quite difficult to burn effectively. Preferred Utilities Manufacturing changed this.

Liquid smoke is part of a family of products whereby wood is converted from a solid into a liquid. Wood pulp is heated in the absence of oxygen during a process called pyrolysis. This produces bio-oil—or liquid wood.

Unlike petroleum or natural gas, liquid wood fuel is a 100% renewable resource: the wood used to create the fuel can be balanced by replanting new trees. Liquid wood is also carbon efficient because the replanted trees offset carbon emissions, which eliminates the need to purchase separate carbon offsets. As a result, liquid wood is 81 percent more carbon efficient than natural gas, and 88 percent more carbon efficient than petroleum.

Once it’s being properly fed to the burner, liquid wood behaves pretty much just like traditional fuel oils. This means that existing boiler equipment can be retrofitted for use with liquid wood, dramatically decreasing conversion costs compared to other biofuels.Green Oil

So why haven’t we seen the widespread adoption of liquid wood as a fuel oil? After all, the basic chemistry isn’t new—liquid smoke has been around for more than 100 years. Ensyn, an Ontario biofuel firm, has become adept at producing competitively priced liquid wood fuels, but very few companies have been able to offer reliable systems to burn these fuels, and none have been successful in the marketplace—until now.

Ranger-Brochure-ClipOne of the keys to burning liquid wood is the pump system that delivers the fuel to the boiler. Liquid wood has to arrive in the boiler at much higher and more specific pressures than natural gas or petroleum, and because it is highly acidic, the pipes must be high-grade stainless steel. This all requires advanced pumping and monitoring equipment, combined with the engineering chops to put the whole system into place. That’s where Preferred Utilities shines.

As a hybrid engineering/manufacturing firm, Preferred is uniquely equipped to devise and implement customized solutions to help commercial and residential properties including universities, colleges, hospitals, and more convert their boilers to liquid wood. Compared to other biofuels that can’t be retrofitted to existing systems, such as wood chips or pellets, the logistics and upfront investment of converting to liquid wood for heating fuel is quite reasonable.

But handling the fuel is one thing. Burning it? Another thing entirely. We’re talking about a substance that is 25% water with the consistency of lemon juice. Burning it effectively presents a significant challenge. That’s why Preferred Utilities developed the Ranger Combustion System. As of May 2017, Preferred Utilities burners are the only known burners capable of effectively and reliably firing liquid wood. There are several installations in Ohio, Vermont, and Maine currently burning this fuel with Preferred Ranger Burners.

Ranger,-Open,-Vignette-[web]

Liquid wood also presents an opportunity to go green quickly. It can take years to transition to carbon neutral, but a liquid wood conversion can be completed in a matter of months. We have found that in many cases this extraordinary fuel source can reduce carbon emissions by about 80 percent. For more information about the potential of using liquid wood at your establishment, contact Preferred Utilities at (203) 743-6741.

 

 

 

 

combustion-theory-efficiency

Understanding Combustion Efficiency

The efficiency of a burner-boiler combination is simply the amount of useful energy leaving the system expressed as a percentage of the chemical energy in the fuel entering the system.

Why should I care about efficiency?

Accounting for the loss of useful energy is an important step in evaluating overall cost.

For instance, a change in efficiency by as little as 5% can have a major impact on the operational expense of a facility. The larger the facility’s consumption of fuel and electricity, the more drastic the cost.

General rules of conservation of energy are:

  • Fuel energy “in” equals heat energy “out.”
  • Energy leaves in steam or in losses.
  • Efficiency + 100% minus all losses.

The typical efficiency of a boiler is 80% to 85%. The remaining 15% to 20% is lost. These losses usually fall in the following percentages:

  • 15% typical “stack loss.”
  • 3% radiation loss.
  • 1% to 2% miscellaneous loss.

The table below shows you how to calculate your cost with your efficiency as the variable.

table-operating-costs

Operator / Install Tips

Since a burner must be set up to operate cleanly under worst-case conditions, you must provide enough excess air in order to burn any additional fuel that the metering device at the burner may introduce.

You should also ensure that there is sufficient excess air available on a hot, humid summer day. Remember: there is no way to prevent heat and humidity, but with the proper control systems, you should be able to control fuel flow precisely and efficiently.

Other posts in this series:

  • Understanding Local Law 87 – and laws like it
  • Combustion Theory: The Basics
  • Combustion Theory: Variables – Account for variations in oxygen and fuel
  • Combustion Theory: Efficiency – Calculate efficiency and losses
  • Combustion Theory: FGR – See how flue gas recirculation reduces NOx
  • Combustion Theory: Combustion Controls – Learn how cutting-edge tech can cut your emissions
  • Combustion Systems: Design – Basic principles to follow when designing your combustion system
  • Combustion Systems: Troubleshooting: Burner problems and their causes
  • Combustion Control: Strategies – Linkage vs. Linkageless, and why you should care
 

combustion-theory-variables-header

 Accounting for variations in oxygen and fuel

For any burner-boiler combination, there is an ideal “minimum excess air” level for each firing rate over the turn-down range. Usually, burners require much higher levels of excess air when operating near their minimum firing rates than they do at “high fire.”

More serious factors than dirty fan wheels and dampers inhibit air flow. Varying oxygen content in the air changes the ambient air conditions and effects the input of oxygen into the combustion process.

Hot and Cold Days

On a “standard” day of 60°F, 30 inches barometric pressure, and 45% relative humidity, seasonal temperature and pressure changes, you must take into account that a burner has to deal with additional variables.

When it seems harder for us to breathe on a hot, humid summer day, burners have a problem too. On a hot, humid day, the oxygen flow drops by almost 20% and burners that can’t adapt for this “oxygen lean” air will smoke, soot, and produce noxious emissions.

On a cold, dry winter day, the air flow would increase by 10%, and the burner must adapt.

Viscosity

Variations in pressure across the metering valve and fluid viscosity have the greatest effect on fuel flow.  Viscosity can vary from delivery to delivery and can be affected further by temperature changes.

Having thick oil in burner supply line can reduce the pressure at the metering valve while having thick oil in the return line can increase the pressure at the valve.

Since the burner must be set up to operate cleanly under worst case conditions, enough excess air must be provided to burn any additional fuel that the metering device at the burner may introduce as well as to ensure that the metering device at the burner may introduce as well as to ensure that there will be sufficient excess air available on a hot, humid summer day.

There is no way to prevent heat and humidity, but fuel flow can be closely controlled with the appropriate controls.

Controls are essential to the boiler-burner combination because they will reduce the amount of excess air wasted during weather and fuel changes.

Other posts in this series:

  • Understanding Local Law 87 – and laws like it
  • Combustion Theory: The Basics
  • Combustion Theory: Variables – Account for variations in oxygen and fuel
  • Combustion Theory: Efficiency – Calculate efficiency and losses
  • Combustion Theory: FGR – See how flue gas recirculation reduces NOx
  • Combustion Theory: Combustion Controls – Learn how cutting-edge tech can cut your emissions
  • Combustion Systems: Design – Basic principles to follow when designing your combustion system
  • Combustion Systems: Troubleshooting: Burner problems and their causes
  • Combustion Control: Strategies – Linkage vs. Linkageless, and why you should care
 

Boiler Control RetrofitIn conjunction with Puerto Rico representative M.R. Franceschini Inc., Preferred recently replaced an existing flame safeguard and oxygen trim system with the Preferred BurnerMate Universal (BMU) system on a 500 HP boiler at a pharmaceutical plant outside of San Juan.

In addition to oxygen trim, the BMU is controlling the forced draft fan variable speed drive (VSD), and providing first out annunciation of boiler trips. The BMU was integrated with the existing proprietary feedwater control system and all existing boiler limits.Boiler Control Retrofit with BMU

This steam boiler runs continuously on No. 2 oil, which is expensive in Puerto Rico, so the boiler was tuned for the lowest excess air possible at all firing rates to reduce fuel consumption.

In addition to expensive fuel, Puerto Rico has some of the most expensive electricity rates in the U.S. according to the U.S. Energy Information Administration. Industrial users in Puerto Rico currently pay an average of 14.6 cents/kW-hr compared to the national average of 6.54 cents/kW-hr.

Rate hikes averaging 26%BurnerMate Universal have been announced effective in 2017 for the island. With the new Preferred BMU controller, the forced draft fan VSD speed was kept under 30 Hz from low fire to mid-fire, resulting in electricity savings of over 85% compared to 60 Hz operation.

For more information on the BMU Boiler Control System, click here.

 


How much will you save?
Check out the Preferred Utilities Energy Savings Payback Calculator

Ever tried to justify a retrofit project? Now there’s a better way to crunch the numbers. This app will save you time and money. It analyzes your existing boiler and burner system data and compares it against a proposed modern upgrade, complete with energy savings estimates.

The calculation output in this application is extensive. It includes a fuel analysis, combustion efficiency (existing and projected), fuel consumption, electrical consumption, and C02 credit calculations. Use this tool if you are considering a boiler/burner upgrade.

Used for:

  • Boiler retrofits
  • Burner upgrades
  • Control upgrades
  • Energy auditing

Features:

  • Save your work
  • Recall past projects
  • Print your data
  • Compare Preferred equipment

Energy Saver Payback Tool

 

Combustion Theory

Introduction

Welcome to the Combustion blog series by Preferred Utilities Manufacturing Corporation. To read the introductory post, click here.

This series was inspired by Local Law 87, an environmental regulation passed by New York City legislators. LL87 seeks to reduce the city’s emissions by 50% while increasing the overall efficiency of large residential buildings (over 50,000 gross sq. ft.).

With additional state and local governments instituting similar environmental regulations across the United States, combustion system design and theory is more important now than ever.

Whether you’re a building owner, plant operator, building designer, or system engineer, this blog series will help you make informed decisions on your projects, especially as they pertain to LL87 and laws like it.

Why listen to us?

Because we’ve been doing combustion since 1920. Our rotary-style burners, invented in the 1960s, are still in operation all across New York City–almost half-a-century later.

But we’ve learned a lot since then.

We’re not like a lot of other burner companies. We don’t cut corners. Our products aren’t flimsy and they don’t come cheap. They last. And they perform.

Ultra low emissions. High efficiency. High turn down. Rugged durability. We reached for these marks because we believe in what we do. We love combustion. We love doing it right.

If this sounds like you, then read on.

Basics

The most common industrial fuels are hydrocarbons. This means that they are predominantly composed of carbon and hydrogen. Table 1 lists some common fuels and gives typical values for the hydrogen and carbon contents as percentages by weight. Note that there are some other components besides hydrogen and carbon. Some of these, such as sulfur, are combustible and will contribute to the heat released by the fuel. Other components are not combustible and contribute no positive energy to the combustion process.

Combustion Theory - the basics [table 2]

Table 1

The Chemistry

Table 2 reviews the basic chemical equations, which represent the most common combustion reactions. Note that nitrogen (N2) is shown on both sides of the equations. Except for the formation of NOx (in the parts per million range) nitrogen does not react in the combustion process. The nitrogen must be considered in fan sizing and stoichiometry calculations. Each atom of carbon in the fuel will combine with two atoms of oxygen (or one molecule of O2) from the atmosphere to form one molecule of CO2. On a weight basis, each pound of carbon requires 2.66 pounds of oxygen for complete combustion resulting in the production of 3.66 lb of carbon dioxide.

Combustion Theory - the basics [table 1]

Table 2

Each pair of hydrogen atoms (or each molecule of H2) will combine with one atom of oxygen (or one half molecule of O2) to form one molecule of H2O, or water. On a weight basis, each pound of hydrogen requires 7.94 pounds of oxygen for complete combustion, resulting in the production of 8.94 pounds of water.

By the Numbers

The air we breathe is only about 21% oxygen by volume. For all practical purposes, the remaining 79% is nitrogen. Since oxygen is a little heavier than nitrogen, the percentages by weight are somewhat different. The percentage of oxygen by weight is 23%, and the remaining 77% is nitrogen. Thus, it requires about 4.35 pound of air to deliver one pound of oxygen. Table 3 shows the composition of air.

Combustion Theory - the basics [table 3]

Table 3

A typical gallon of No. 6 fuel oil weighs 8 pounds and is 87% carbon and 12 % hydrogen (the missing percent is sulfur, ash, water and sediment). This gallon contains 6.95 pounds of carbon and 0.96 pound of hydrogen. From the data presented earlier, we can compute that 18.49 pounds of oxygen are needed to burn the carbon and 7.62 pounds of oxygen must be provided to burn the hydrogen in this gallon of fuel oil. This represents a total requirement of 26.11 pounds of oxygen. Since air is only 23% oxygen by weight, it will take 113.5 pounds of air (26.1 ÷ 0.23) for the complete and perfect (0% excess air) combustion of this gallon of fuel. Assuming there are 13 cubic feet of air to the pound, 1476 cubic feet of air are required to burn each gallon of fuel. A 50 gallon per hour burner (about 200 boiler HP) would need nearly 74,000 cubic feet of air per hour (or 1230 scfm) to fire without any allowance for excess air.

The Real World

In the real world, however, there must always be more air supplied to the combustion process than the theoretical or stoichiometric air requirement. This is because no burner made is this “perfect”. This “extra” air is referred to as “excess air.” If 20% more than the theoretical air requirement is supplied, we say that the burner is operating at 20% excess air. Another way of stating the same thing is to say that the burner is operating with 120% “total air.”

Complete combustion of our one gallon of No. 6 fuel oil with 20% excess air would require 136 pounds of air. The 50 gallon per hour burner would actually require about 90,000 cubic feet of air per hour.

For any particular burner-boiler combination, there is an ideal “minimum excess air” level for each firing rate over the turn-down range. Greater air flows would waste fuel because of the increased mass flow of hot gases leaving the stack. Lesser amounts of air would cause fuel waste because the fuel would not be burned completely. Typically, burners require much higher levels of excess air when operating near their minimum firing rates than they do at “high fire.” Table 4 shows a typical relationship between percent firing rate and the excess air required to insure complete combustion of the fuel. In many cases, even though stack temperature might decrease at low fire, efficiency suffers because so much of the fuel energy is lost to heat this excess air.

Combustion Theory - the basics [table 4]

Table 4

 

Other posts in this series:

  • Understanding Local Law 87 – and laws like it
  • Combustion Theory: The Basics
  • Combustion Theory: Variables – Account for variations in oxygen and fuel
  • Combustion Theory: Efficiency – Calculate efficiency and losses
  • Combustion Theory: FGR – See how flue gas recirculation reduces NOx
  • Combustion Theory: Combustion Controls – Learn how cutting-edge tech can cut your emissions
  • Combustion Systems: Design – Basic principles to follow when designing your combustion system
  • Combustion Systems: Troubleshooting: Burner problems and their causes
  • Combustion Control: Strategies – Linkage vs. Linkageless, and why you should care
 

Local Law 87 - NYCThe New Paradigm

What does Local Law 87 – and laws like it – mean for you?

With increasing regulatory effort to protect the environment, preserve energy, and reduce carbon emissions, states and cities have taken matters into their own hands by way of local legislation.

New York City’s Local Law 87 (LL87) mandates that buildings over 50,000 gross square feet undergo periodic energy audit and retro-commissioning measures, as part of the Greener, Greater Buildings Plan (GGBP).

The intent of this law, and laws like it, is to inform building owners of their energy consumption through energy audits. Energy auditors analyze a building’s energy use and aid in retro-commissioning, which is the process of ensuring correct equipment installation and performance. Ultimately, these audits will help make buildings more efficient.

Why this matters:

Environmental regulations like LL87  make the selection, design and maintenance of modern combustion systems extremely important.

This blog series will educate building owners, operators, and engineers affected by LL87 and laws like it. It will cover the basics of combustion theory, how to properly design a combustion system, and how to effectively control your combustion processes with modern technology.

By the conclusion of this series, you will be armed with the knowledge you need  to make informed decisions regarding your projects and efforts to meet these expected environmental regulatory requirements.


Combustion Terms

Combustion is the process by which the hydrogen and carbon in fuel is combined with oxygen from the air to release heat.

Byproducts include carbon dioxide, water vapor, left-over nitrogen from the air, and possibly unreacted oxygen and/or fuel components.

Combustion Control is the maintenance of the proper fuel and air flows into this process to produce the amount of heat energy required while consuming the least possible fuel and generating the lowest amount of pollution.

The following blog posts will contain further information regarding the combustion process as a whole. Among some of the topics we will cover:

  • Combustion Theory: The Basics
  • Combustion Theory: Variables – Account for variations in oxygen and fuel
  • Combustion Theory: Efficiency – Calculate efficiency and losses
  • Combustion Theory: FGR – See how flue gas recirculation reduces NOx
  • Combustion Theory: Combustion Controls – Learn how cutting-edge tech can cut your emissions
  • Combustion Systems: Design – Basic principles to follow when designing your combustion system
  • Combustion Systems: Troubleshooting: Burner problems and their causes
  • Combustion Control: Strategies – Linkage vs. Linkageless, and why you should care