Today, high fuel bills and energy surcharges from vendors are common in manufacturing. In the face of rising energy prices, many companies seek emerging technologies and exotic developments in an attempt to offset fuel bills. Addressing weaknesses of conventional burner air/fuel ratio controls may produce larger and easier efficiency gains than new technologies like exotic burners, recuperation and alternate fuels.
Since the beginning of industrial heating, fuel and air have been controlled primarily by two means: mechanically linked valves and pressure impulse regulators. While these systems are certainly adequate to operate an industrial burner, they are by no means optimal. Often the shortcomings of a burner's ratio control are hidden by flexible burner technologies that maintain stability under less than optimal conditions. Much like the cliché “Out of sight, out of mind,” burners that light and run often get no attention or measurement to check their operation and adjustment.
Back in the 1970s, another fossil-fuel-burning industry learned the same lessons and resolved their issues with control technology. Prior to the OPEC oil embargo, the U.S. auto industry manufactured cars that were big and inefficient. These cast-iron monsters' engines controlled their fuel/air ratios with mechanical devices called carburetors.
Today, modern engines have made substantial gains in fuel efficiency and clean combustion (table 1). Figure 1 shows a 61 percent increase in fuel economy in U.S. passenger cars since 1973. How did these motors evolve to increase efficiency and reduce tail-pipe emissions? Part of the solution came in changing mechanical air/fuel ratio control to intelligent engine management. The majority of cars produced today operate their power plant with air/fuel monitoring technology, an engine computer and electronic throttle control. Effectively, intelligent engine management has made the carburetor an extinct animal, or at least placed it on the endangered species list.
If the auto industry has embraced electronic engine management, why can't the industrial heating industry advance to smart burner controls? After all, aren't engines and burners very similar devices? Both burn fuel. Both use air as an oxidant in combustion. Both are under enormous pressure to produce better efficiencies and control pollutant emissions. The only real difference is that engines work to extract mechanical power from fuel while burners extract thermal power.
The best clue is provided in the observation that better controls usually take a larger purchase investment. Better controls can easily be called an investment because the operating costs of an industrial burner (i.e., the fuel bill) quickly surpass the price of the entire heating system, usually in a few months. Many equipment manufacturers don't address operating costs because there are no government regulations or widely published standards like the automotive industry's Corporate Average Fuel Economy (CAFE) laws.
Today, several manufacturers offer digital parallel-positioning ratio-control systems. These packages improve burner efficiency by more tightly controlling simultaneous airflow and fuel flow. Through actuators directly linked to valves with no impulse lines or linkages, control errors associated with pressure lags, mechanical wear and control drifts are reduced to a negligible level. This all means better combustion efficiency and often more precise temperature control. Just like in the car engine, better-controlled burners use less fuel.
High-resolution ratio controls also cut fuel costs by acting like a cruise control. In combination with a properly tuned temperature controller, high resolution fuel/air ratio controls greatly reduce temperature errors and instability, often called hunting, which make poor use of fuel like a lead-foot driver.
Other similarities between new ratio controls and modern engines add value to a burner system. A major drawback of carbureted engines was maintenance. Not long ago, many car companies recommended engine tuneups every 10,000 miles. Today, most engine tuneups are 10 times less frequent at 100,000 miles. What advancement allowed this dramatic improvement in engine reliability? Again, the answer is intelligent engine management through controls. All those same features produce similar benefits for industrial burners with electronic fuel/air ratio control. Imagine the value of burners that alert the operators when they are developing an issue like dirty valves or clogged air filters.
While burners and car engines share a lot of similarities, they are different in other regards. Your industrial burner won't be featuring cup holders or an entertainment system anytime soon. Your car engine certainly costs a lot less to operate on average. Most importantly, your industrial burners can be dramatically improved in fuel efficiency through better ratio controls so you can sleep better at night with more operational profits.
Contact your preferred burner manufacturer or controls supplier to learn more about intelligent, fuel/air ratio control systems. It's doubtful that PETA will object if you help make extinct the carburetor by upgrading your burner ratio controls. PH