Your manufacturing process generates waste, and no matter what you do to minimize your waste generation, you can't completely get rid of it. This presents a sustainability problem: Your nonhazardous waste does not have an already-established solution. The most commonly thought-of solution is to convert the waste into energy.
Most of the time, the problem with nonhazardous waste is you are not sure whether it can be converted into energy. So even though you want a sustainable solution, you don't know where to find a provider that can handle it. This is the point where you have to start digging for answers.
Gasifiers versus cement kilns
Gasifiers and cement kilns both use waste as fuel. Gasifiers have a broader range of acceptance than cement kilns. But when gasifiers operate at lower temperatures, they produce higher volumes of emissions and generate more ash. The problem with using gasifiers, then, is scrubbing the output gases and dealing with high landfill rates. Cement kilns, on the other hand, have a pickier temperature range at which they operate, but are also more efficient and environmentally sound than gasifiers.
Environmental controls vary according to the method used to convert waste into energy. Gasifiers use waste in a fluidized bed reactor to boil water, capture the steam and power a turbine, converting waste into electricity that goes back to the electric grid. Their operating temperatures range from 750 degrees Fahrenheit to 1,000 degrees Fahrenheit. The gasifier's scrubbers collect the uncombusted emissions, and the scrubber material goes to the landfill along with the ash at the end of the process. Gasifiers generally produce ash at about 20-30 percent of the total mass input, so 100 tons of input results in 20-30 tons of ash going to landfill.
What makes cement kilns unique is 70-75 percent of the raw material used to make cement is limestone, which is the primary material used in gasifiers' emissions scrubbers.
In the first step of using waste-to-energy to power a cement kiln, the waste enters the cement kiln in an area that reaches up to 1,800 degrees Fahrenheit, much hotter than typical gasifiers. When the combustion process of the cement kiln is completed, the emissions must then travel through several hundred tons of limestone to exit the kiln, while remaining in a high-temperature environment for several seconds. This period is referred to as "residence time." With high combustion temperatures throughout the process, a long residence time and tons of limestone acting as a natural scrubber as emissions pass through, cement kilns burn contaminants at a 99.99-percent destruction ratio efficiency. During the process, the ash becomes part of the cement at the molecular level and therefore cannot leach from the kiln into the environment.
Cement kilns are the ideal solution for waste-to-energy needs. Unlike gasifiers and other sustainability solutions offered, cement kilns represent a near-total reduction in the "last mile" of waste that you want to stay out of a landfill.
If you do a little digging, it's easy to see cement kilns are the solution to your nonhazardous- waste sustainability needs.
For more information, visit www.vlsrs.com or call (877) 861-8588.