If you have lived in McPherson long, you have probably noticed flames burning on towers at the NCRA refinery.
Those flares are a part of the environmental safety system at the plant. Flares act as a safety relief valves for the facility.
When gases build up in various systems at the plant, the excess pressure is relieved by burning the gases through one of the refinery’s seven flares.
The main flare is an orange and white stripped tower on the west side of the plant, which can be seen from U.S. Highway 81.
NCRA has a permit that governs its dispersal of pollutants into the air. If it exceeds the amount of pollutants dictated by the government, it must report those amounts to the local and state officials within as quickly as 15 minutes of their dispersal into the air.
Rhett Heflin, manager, NCRA Environmental Department, said the refinery typically makes one of these reports a month. On July 9, the plant exceeded it output of sulfur dioxide.
The release was 561 pounds of sulfur dioxide, and the limit is 500 pounds.
However, the refinery did not exceed its standards for ambient air quality during that period.
Marian Massoth, air permit section chief at Kansas Department of Health and Environment, said the ambient air quality is the chief measure of air quality in a given area.
She said to her knowledge, there had been no recent complaints of NCRA exceeding ambient air quality standards.
Regulatory agencies set the ambient air quality standards at a level with the weakest residents of the area in mind. This includes children, those with weakened lungs and asthmatics, Massoth said.
However, she said factors, such as distance from the emissions site, wind speed and wind direction, can all be factors in how pollutants affect local residents.
Heflin said there likely will be another flare event Tuesday as the refinery brings on new electric compressors for its cat cracker unit.
These are expected to be clean gases. Clean gases that are burned at the flares are similar to those residents would encounter in their everyday lives, such as propane, natural gas, butane or hydrogen.
Occasional flare burns are a normal part of the operations at the plant. The flares burn excess hydrocarbons, which cannot be recovered or recycled.
Residents should not be concerned when they see one of the flares burning, Heflin said.
Although the refinery tries to minimize the use of its flares, it is sometimes necessary to burn excess gases when parts of the plant are started up or shutdown because of maintenance or because there is a power outage.
The plant has redundancies on its electric system and emergency generators to run its control systems in case of a power outage.
Page 2 of 2 - However, the flares have pilot lights that are required to be lit at all times in case there would be an emergency situation during which gases would need to routed to the flares.
Steam is mixed with the gases when they are burned at the flares. This system ensures that the flare system can produce maximum combustion of the hydrocarbons with the least amount of emissions. If not enough steam is present, the flares may temporarily produce smoke. Once the steam is adjusted, the smoke should abate. Smoke does not mean the flares are working incorrectly or there is any problems at the plant.
In addition, the flares may emit a rumbling sound. This sound comes from the mixing of air, vapors and steam during the flaring process.
“The NCRA Refinery is committed to ensuring that our operations run safely and with minimal impact on the community and the environment,” the company said in a written statement. “We strive to minimize flaring, keeping it to the times that is necessary for the continued safe operations of our plant. So when you see one or more flares burning, be assured that their role is to keep the refinery running safely.”