America: New, less-polluting cement plant rises in Ravena

Byszheng

Updated Fri, 04 Dec 2015 09:30:06 GMT

So far, the multimillion dollar rebuilding of a five-decade-old cement plant in Ravena begun in 2014 is on track to be mechanically completed by next summer.

During a recent tour of the Lafarge North America plant on Route 9W, officials showed off the progress, which includes a new, 200-foot German-designed rotary kiln that will be much more efficient and less polluting than the two 600-foot kilns that will be replaced.

Senior Project Manager John Light said the new plant — which will cost more than $300 million — will meet the pollution reduction requirements that were part of a 2010 agreement between Lafarge and state and federal officials.

The agreement initially called for the new kiln to be ready by June 2015, but that was pushed back a year, in return for the company agreeing to operate one of its current kilns less frequently. Under the agreement, Lafarge also agreed to pay a penalty of more than $5 million to federal and state agencies while spending $170 million to upgrade facilities at 13 plants across the country.

As part of the construction extension at Ravena, Lafarge must report construction progress to the U.S. Environmental Protection Agency. Reports filed in June and November show the project remains on schedule, according to the regional EPA office in New York City.

Light said the schedule calls for the plant to be mechanically ready to operate by the end of June, but that routing and testing of electrical power to make it operational would still have to be done. "So far, so good," he said. "And our schedule depends on the timely delivery of equipment from our suppliers. "

The new kiln will use a dry process to convert limestone from a nearby quarry into cement, unlike the current kilns, which now mix large amounts of water from the Hudson River into the process.

The absence of water means less coal will have to be burned to fire the kiln to its 2,800 degree operating temperature, which is expected to cut emissions of sulfur oxides by 95 percent, nitrogen oxides by 60 percent, fine particulate matter by 37 percent, and mercury by 66 percent, according to figures from the state Department of Environmental Conservation.

New pollution controls will also remove pollution from the kiln exhaust.

Light also said the new plant will no longer use coal fly ash — a waste from coal-fired power plants that contains significant amounts of toxic mercury — as part of the cement-making process. The ash contains silica, which helps bind the cement; alumina and iron now will be used instead.

Also, said Light, the new plant will consume about 90 percent less water from the river, and will update its water intake screens to reduce the amount of fish and other aquatic life that are drawn into the plant's machinery. For most of its water, the new plant will use pumped groundwater from its quarry, Light said.

Currently, workers are building a raw mill, where up to 400 tons an hour of limestone and shale will be ground into a fine powder on a massive turntable assembly powered by a 6,000-horsepower motor, Light said.

Also under construction is a pre-heater tower, which will heat the mix to temperatures as high as 1,400 degrees before it enters the new rotary kiln, where the mix forms into solid nuggets called klinker. The klinker will then be carried to the exiting grinding mill, where it is made into cement powder, bagged, and shipped.

The new kiln was designed by KHD Humboldt Wedag, an engineering firm based in Cologne, Germany.

Light said the project is employing as many as 200 workers a day. The massive steel structures for the project are being fabricated in China, shipped through the Panama Canal, and brought up the Hudson to the Port of Coeymans, he said. From there, parts are brought by truck on private roads to the adjacent cement plant property.