Tucked within the Appalachian and Blue Ridge Mountains, the Roanoke Cement Company (RCC) plant in Troutville, Va., is keenly aware of its environmental impact on this lush, verdant valley. Virginia’s only cement plant is practicing concrete thinking with land stewardship, increasing its energy efficiency, and minimizing its environmental impact.
RCC’s Troutville plant, owned by Titan America LLC, earned the Overall Environmental award at the Eighth Annual Cement Industry Environmental and Energy Awards (2009), finished runner-up in the Energy Efficiency category, and was a finalist in the Environmental Performance category. RCC was a finalist for the Overall and Land Stewardship awards in 2008.
The Environment & Energy Awards, presented annually by PCA and Cement Americas magazine, honor plants that go above and beyond local laws and government regulations for the industry in a number of ways.
The success in Troutville begins with increasing efficiencies in its operations, which in turn reduces its environmental impact.
What Can We Turn Off?
With meters in-hand the RCC’s Energy Team took to the field in an effort to measure energy usage. The team calculated energy usage by kilowatt per hour (kwh), per ton of finished cement.
“We knew we could program our machinery to reduce energy usage and consumption,” said Chris Bayne, energy manager and electrical engineer.
Bayne and his multi-disciplined team of process, mechanical, maintenance, and electrical expertise challenged plant operators, “What can we turn off?”
After a thorough audit, the Energy Team determined to automate their ‘turn-off’ capabilities. RCC now relies on several programmable logic controllers (PLCs), or digital computers used for automation of industrial processes. The PLCs are designed for multiple input and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact.
RCC also challenged its employee’s mindset about energy usage and encouraged new ideas for energy savings. “RCC’s energy policy is to convert every employee from an energy user to an energy saver,” says Bayne.
In an obvious answer to the basic question, “What can we turn off?” RCC reduced the 100 lights above the 400-foot pre-heater tower to two flashing red lights. The reduction changed the concept of a signpost for the plant to a safety precaution for small aircraft. “We knew we would make the neighbors happy if we just shut the lights off at night,” said Plant Manager Kevin Baird.
The Energy Team also completed an air audit. The existing air systems may have been the most inefficient energy user at the plant – a single horsepower pneumatic tool that requires 10 horsepower of electricity. Through system tweaks, RCC reduced the number of air compressors from seven to three by combining them into a single unit and yielding $230,000 in electricity savings.
From the simplest modest changes to more technical, systemic fixes, RCC worked hard to score energy reductions. Since 2007, the plant achieved a five percent reduction in electrical energy consumption. Normalized for production, the plant reduced its consumption of energy by 3,810,000 kwh in 2008. This reduction can be translated into the prevention of nearly 2,000 tons of coal burned for energy, the equivalent of leaving 20 loaded railroad cars at the station.
Reduce, Reclaim, Reuse
Equally important to its improved efficiencies in operation, RCC is reducing its environmental impact by better managing its waste and improving water and air quality. The goal is to reduce, reclaim, and reuse wastes and thereby minimize the disposal requirement.
One of the primary wastes produced at any cement plant is cement kiln dust (CKD). Now at RCC, no new CKD leaves the cement manufacturing process. In 2007, the plant replaced the electrostatic precipitator (ESP) on the alkali bypass system with a high-collection-efficient bag house. The collection efficiency of the bag house reduced the visible emissions from the main stack by as much as 40 percent, resulting in an average opacity reading reduction of at least five percent.
The $2.5 million ESP replacement project also allowed RCC to eliminate CKD landfill needs. Rather than placing in a landfill, the vast majority of CKD created is used in the finish mills for masonry products or recycled into the cement manufacturing process.
To compliment the bag house initiative, RCC installed new continuous emissions monitoring systems (CEMS). From 2005-2007, CKD production decreased by nearly 47 percent and decreased by a third in 2008.
Programs already in place by 2008, continued to consume waste material tonnage. RCC used nearly 200,000 tons of waste including synthetic gypsum, foundry sand, steel slag, fly ash, and lime kiln dust in 2008 alone, saving the otherwise significant environmental impact of their disposal.
RCC also repurposes CKD as ‘Cal Plus.’ Local farmers can use this agricultural project, comprised primarily of CKD, to neutralize the alkaline characteristic of the Virginia soil. The Virginia Department of Agriculture and Consumer Services recently approved the product using fresh CKD as well as CKD reclaimed from landfills. In 2008, RCC removed 2,880 tons of CKC from its landfill for beneficial use.
A new roller crusher helps cut energy consumption as the conveying distance is reduced by 50 percent. The hauling distance, from the quarry to the crusher, is also halved – meaning less fuel and therefore less CO2 emissions. Additionally, there is a reduction in fugitive dust over the shorter hauling roadways.
RCC also completed the installation of a dust suppression system in 2008, including six high-pressure water sprays that shoot 40-50 gallons of water per minute and aggressively assist in the dust suppression efforts.
At the bottom of a tapped-out quarry, RCC installed an intricate liner system that enables the storage of more than 15 million gallons of water. The stored rainwater is stored instead of running off to the neighboring Catawba Creek, mini mizing erosion and controlling potential water pollutants. The pond is put to use by pumping 11 million gallons of water through pipes that cool machinery at RCC such as compressors and fans. With the addition of upgrading its freshwater system and pumping only what the plant needs, consumption has been lowered by 22,000 gallons per day.
RCC has successfully conserved land by allowed a portion of its land, three-fourths of the Andy Layne Memorial Trail adjacent to Catawba Creek, to be utilized for the sake of recreation and the enjoyment of nature enthusiasts. The area provides access for hikers and backpackers to enjoy the Virginia stretch of the Appalachian Trail. Outdoor enthusiasts have ranked the trail through RCC among the top day hikes in the country.
For the past three years, RCC has been involved with improvement projects on Catawba Creek, helping to haul away debris along a five-mile stretch that runs through the plant property. Nearly 40 truckloads have hauled away the collected trash during this effort.
Additionally, in 2007, RCC designed and planted an apple orchard at the southeast end of its property, improving the plant’s overall appearance. Previously this area was the site of an ‘old bone yard’ for old parts and equipment and considered an eyesore by neighbors, employees, and visitors. More than 100 trees are currently in the ground with plans for more than 200 over the next few years.
RCC is dedicated to continuous improvement, convinced that environmental stewardship is the most important characteristic to becoming a good corporate citizen.
On top of all of these efforts, the U.S. EPA and Department of Energy honored RCC with a prestigious ENERGY STAR® award in 2007 and 2008 for its energy efficient solutions, protection of the environment, and reduction in greenhouse gas emissions. Moreover, RCC’s parent company Titan America became an official ENERGY STAR® partner in 2008.