Rock-Tenn Operations
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Rock-Tenn Energy Needs (RCAP Presentation October, 2007)
Rock-Tenn Current Manufacturing Process
Frequently Asked Questions
Why are they seeking a new energy source?
In August 2007, Rock-Tenn’s St. Paul plant lost its primary energy source when Xcel Energy’s High Bridge power plant was shut down. Steam energy from the coal-fired power plant on Shepard Road traveled along six miles of pipe to Rock-Tenn’s plant near Vandalia Avenue. The pipeline cost Rock-Tenn about $40 million when it was constructed in 1984. Today, Rock-Tenn runs its own boilers to generate an enormous amount of thermal and electric energy needed to recycle waste paper and cardboard to pulp and then to usable boxboard. Rock-Tenn is working to reduce its energy needs by improving energy efficiencies and expanding conservation measures. Switching to fuel oil and natural gas has increased Rock-Tenn’s energy bill as much as $1 million per month.
What triggered the study of renewable energy options for Rock-Tenn?
In 2007, when it became apparent that the High Bridge plant would be shut down and that Rock-Tenn would lose its source of affordable thermal power, the Minnesota House and Senate passed a law mandating that a study of renewable fuel options for Rock-Tenn be undertaken. Separately, the Legislature passed a law committing the state to reduce global-warming greenhouse gas emissions by 15 percent by 2015, 30 percent by 2025 and 80 percent by 2050, which would be aided by the use of renewable fuels at Rock-Tenn.
What is the employment profile for Rock-Tenn?
The USW members at Rock-Tenn ratified a new 3 year Labor Agreement on August 20th, 2007. The employees at the mill work a demanding 4-shift southern swing schedule, consisting of 7 on 2 off, 7 on 2 off, 7 on 3 off schedule, but they are compensated for this schedule with the overtime premiums listed below. The current Average Hourly wage for the 400 USW Production, Maintenance and Janitors without overtime premiums is $21.25/hr. and the avg. annual take home pay for USW workers is $60,000.00 a year.
What is electrical energy? What is thermal energy?
Electrical Energy or Electricity is the movement of electrical charges through conductors or wiring. Rock-Tenn uses electrical energy to power equipment, motors and lighting throughout the recycling plant. Thermal Energy or heat, is the internal energy produced from the vibration and movement of the atoms and molecules within substances. Rock-Tenn uses thermal energy in the form of steam.
What are the current energy demands at Rock-Tenn?
The Rock-Tenn Facility currently needs 20 Megawatts of electrical power and 2,250,000,000,000 British Thermal Units (BTU) of thermal energy per year for operations, which is equivalent to all of Downtown St. Paul’s heating needs. The paper recycling process uses approximately 83 percent of the thermal energy, with the balance (17 percent) being used for non-process loads including building heating.
What is cogeneration?
Cogeneration, also known as combined heat and power (CHP) is an energy plant that simultaneously generates both electricity and thermal energy. Conventional power plants generally emit the heat created as a byproduct of electricity generation into the environment through cooling towers, as flue gas, or by other means. CHP captures the byproduct (waste) heat for domestic or industrial heating purposes, located either very close to the plant, or distributed through pipes to remote facilities. Rock-Tenn currently uses cogeneration/CHP to generate all of it thermal energy needs and approximately 40 percent of its electrical energy needs.
Is the process Rock-Tenn is using the best and most sustainable process?
Rock-Tenn’s St. Paul plant has been recycling paper for 100 yrs. Over this time period, it would be fair to say that none of the original equipment is being used in the current process. In fact, Rock-Tenn has had a very aggressive capital program to update and improve our recycling facilities to the point where we are using some of the most state-of-the-art equipment in the industry. These investments in newer technologies help make this company sustainable both economically and environmentally. Most of these investments focus on trying to increase the amount of paper we can recycle while reducing the amount of outside resources we need. For example, in the past 12 years the mill has completed recycled paper cleaning upgrades at a cost of over $15 MM to improve contaminant processing capabilities due to the degrading quality of waste paper streams. Over this time the systems have been further optimized to maximize contaminant removal efficiencies while reducing electrical loads.
Does Rock-Tenn operate twenty-four hours a day?
Rock-Tenn operates 24/7 and has a very consistent energy demand. However, when any one of our four paper machines goes down the steam demand drops by 25% almost immediately. This results in a significant variance in the process steam demand. Of course, the steam demand also varies with the heating needs throughout the year.
What kinds of motors are in use at Rock-Tenn? Is there energy savings from the motors?
Rock-Tenn uses a wide variety of electric motors from small to quite large. Rock-Tenn has had a program to improve the efficiency of these motors as well as reduce the overall operation's electrical demand for many years. The program includes using premium efficiency motors on new equipment and to replace less efficient motors with premium motors as they fail. More recently Rock-Tenn has installed variable speed drives (VSDs) on several motors which further improves their efficiency.
Why does the paper need to be dried with steam? Could it be air-dried?
The paper drying process at Rock-Tenn actually uses thermal energy in the form of steam that is generated in the boiler, through the steam turbine, and into the process. Once in the process this thermal energy is used to heat water that separates the paper fibers, to heat the metallic can dryers that evaporate the water off the paper, and to heat forced air that further dries and finishes the paper. Steam is the most efficient and cheapest method for distributing this thermal energy from the boiler to the manufacturing process. Relying on air-drying alone would require a much larger and far less efficient process.
What is the estimated fuel mix at Rock-Tenn?
Rock-Tenn's annual fuel use is estimated at a split of 25% natural gas and 75% fuel oil. This is based upon projections of when each fuel will be most affordable. Nine months out of the year (winter), fuel oil is usually more affordable than natural gas. During the summer, natural gas is typically more affordable than fuel oil. Again, this is only an estimation or projection. The decision on what fuel to use is made on a daily basis primarily based upon price.
Where can I find out what the emissions at Rock-Tenn are right now?
Graphs of Metro Area Monitoring (Excel spreadsheets) and the 2009 Draft MPCA Monitoring Plan have both been posted to http://www.rtadvisory.org/emissions.php. Barr Engineering noted that the current Rock-Tenn emissions are included in the current ambient monitor measurements. In addition, the MPCA has an ambient monitoring data website (http://www.pca.state.mn.us/data/edaAir/ambientSearch.cfm ) where data can viewed and downloaded. Barr Engineering has noted that methodology for data collection may have been adapted over time, making data comparisons a bit more challenging. If additional data is needed, please contact Rick Strassman (MPCA) at 651/296-7754 or rick.strassman@pca.state.mn.us.
What is the sulfur content of the oil Rock-Tenn is buying and burning?
The sulfur content of No. 6 fuel oil supplied to Rock-Tenn cannot exceed 1.5%. This is the upper specification limit. The average of oil received thus far is 0.87% with a simple range from 0.64% to 1.25%. Emissions of Hg will be estimated using the appropriate EPA AP-42 emission factor.
What is the current impact of trucking and transportation?
On a typical day, Rock-Tenn receives approximately 75 truck loads of waste paper for recycling. Fuel use and emissions from those trucks are a function of distance traveled, type of truck, weight, type of roads traveled, speed of trucks, age of trucks, type of fuel, and how well the truck is maintained. If the average truck travels 100 miles and gets an average of 10 miles to the gallon, the fuels used per day would be: 75 trucks per day x 100 miles per truck x 0.1 gallons per mile=750 gallons fuel per day. The US Department of Transportation Federal Highway Administration estimated emissions are available at www.fhwa.dot.gov/environment/freightaq/appendixb.htm.
Based on the miles estimated by the US DOT, the annual emissions from the trucks would be (in tons/year): VOC - 1.8, CO - 9.6, NOx - 51, PM10 -1.2. Some of the factors that are not accounted for in this gross analysis are: emissions from trucks traveling to an alternative paper recycling facility, emissions from trucks traveling to a disposal facility if the waste paper is not recycled.