Seneca Foods Reduces Fuel and Electricity Costs with XPlus Burner and Controls Retrofit
Seneca Foods, the maker of canned fruits and vegetables including the brands Libby’s, Aunt Nelly’s, Read, Stokely, and Festal, contacted Todd Moore, president of Combustion Heat and Power, initially to help evaluate several proposals for a new steam boiler. All the mechanical contractors in the area essentially quoted what the plant asked for, a 200 HP high pressure steam boiler to burn digester gas. The boiler was going to be run at high pressure during the canning season, and low pressure during the off-season to negate the requirement to have an operator on hand.
XPlus burner with BurnerMate TS fully metered combustion control system on a 1954 Bros watertube boiler
Moore thought they could accomplish all their objectives with less complexity by installing a hot water boiler instead of a steam boiler. Also, Moore insisted the plant install a 300 HP boiler instead of a 200 HP boiler in the event the digester plant was able to produce more gas in the future. Moore also thought his company could do the job. “Everyone thinks of us as a boiler tune up company, not an installation contractor, but I knew we could do this project,” he said. It took him a week to line up the Hurst boiler, Power Flame burner, and Preferred BMU controls. “I was offering a lot less maintenance, a lot less headache, and the opportunity to use more digester gas.” A week later he had the project.
Moore also saw an opportunity to save fuel at the plant by replacing the Cleaver-Brooks burner on their 1954 Bros watertube boiler. The burner they had on the Bros unit ran at about 8% oxygen, according to Moore. We couldn’t drop the oxygen without making a lot of CO. So we offered to replace the inefficient burner with a more efficient XPlus burner and be able to use the digester gas on this burner at the same time.
Using the Preferred Utilities Payback Calculator, Moore estimated the plant would save over $50,000 per year of fuel and over $3,000 worth of electricity with the new burner. The reduction in natural gas consumption would reduce the plant’s carbon dioxide emissions by over 600,000 lbs per year. In addition, up to a quarter of the heat input of this burner comes from the digester gas produced from corn and bean waste produced by the cannery.
The digester gas plant had been a challenge. Originally, a partnership with Xcel Energy was supposed to take the organic waste from the cannery, convert it to digester gas, and sell it to the local municipal utility. However, the corn and green bean waste from the cannery was tough and fibrous, and difficult to convert to the methane desired by the utility. Eventually, however, after a lot of research and effort, Seneca was able to produce digester gas at up to 600 Btu/ft3 and now the plan was to burn the digester gas at the cannery.
The Xplus burner was designed to burn a single mixed gas fuel, either a mixture of digester gas and natural gas, or just natural gas through the same fuel train and same gas manifold. A mixing station controlled by Preferred loop controllers would preferentially use all the digester gas available, and make up for any additional fuel demand using natural gas. This way the plant burned as much “free” fuel as was available. The plant operators are able to select whether they will fire natural gas or a mixture of natural gas and digester gas.
Digester gas train with mixing station to mix natural gas and digester gas before it goes to the XPlus burner.
With the fuel mixing done upstream of the burner safety shutoff valves, the added cost and complexity of the mixing station was offset by the ability to provide a single fuel burner and burner management system. Because the digester gas contains sulphur and water, all the burner and piping components were made from 316 stainless steel to resist corrosion.
Preferred supplied a BurnerMate TS for the new Xplus burner featuring a fully metered combustion control system that adds natural gas flow and digester gas flow together to determine the optimum air flow setpoint for safe, low excess air combustion. This system works automatically whether selected to natural gas firing or mixed natural gas and digester gas firing. It also compensates automatically for varying amounts of digester gas available to the burner.
The BurnerMate Universal on the firetube boiler was set up for parallel positioning with oxygen trim to compensate for small changes in ambient temperature and digester gas heating value. This boiler is used primarily for heating the 550,000 ft2 canning facility.
Installing the new firetube boiler, stripping the Cleaver-Brooks burner off the Bros boiler, and installing the Preferred Xplus burner, gas piping, mixing station, and controls took about six months. Commissioning the burner and controls took an additional two weeks. Commissioning the BMU on the firetube boiler took four hours. According to Seneca Foods plant manager Paul Hendrickson, “The startup and the basic test firing happened before our busy season, so we were able to run our boilers and do a lot of trial work while we were not in production.”
The burner achieved excess air levels below 15% at high fire. The FD fan motor speed at high fire was 43 Hz and 12 Hz at low fire, so electricity savings should be greater than predicted. NOx was reduced from approximately 120 ppm with the Cleaver-Brooks burner to less than 50 ppm firing a mix of digester gas and natural gas.
“Everything went real well for as complicated as the system is,” said Moore. “It was one of those installations you can hang your hat on.”
“Combustion Heat and Power has been prompt and up front with anything that was needed,” said Hendrickson. “We have been very, very pleased with their service.”
In a letter to Preferred, Moore stated, “This project is the biggest I have taken on since I bought the company (CHP). I put a lot of faith in your employees to help me get the job done and they delivered. This project is a huge accomplishment for my company, your company, and the XPlus burner and PI controls.
The owner of Seneca Foods has been to the plant since the Preferred equipment was installed and he is very impressed with the new burner especially. “He is an engineer by trade, and he is just taken by the design of the burner,” said Moore.
Based on the good results at this plant, Seneca Foods has committed to getting more digester gas out of their existing system, and looking to repeat this performance at some of their other plants.
- Seneca Foods Reduces Fuel and Electricity Costs with XPlus Burner and Controls Retrofit
- 11 November, 2011
- Preferred supplies equipment and expertise to save over $50,000 per year of fuel and over $3,000 worth of electricity with a new burner. The reduction in natural gas consumption would reduce the plant's carbon dioxide emissions by over 600,000 lbs per year. In addition, up to a quarter of the heat input of this burner comes from the digester gas produced from corn and bean waste produced by the cannery.
