New revision to Irving Oil refinery permit sets limits on sulfur block emissions
Irving Oil is being ordered to limit emissions from the sulfur block at its the Saint John refinery to a level which should significantly reduce recent ambient air quality exceedances recorded at a monitoring station south of the facility.
Following discussions with the company, New Brunswick's Department of Environment and Local Government has amended the current air quality operating approval for the refinery, setting limits for total emissions of sulfur compounds (expressed as sulfur dioxide) from the refinery's sulfur block to less than 10,000 kilograms (kg) per day, based on a monthly average, and less than 15,000 kg per calendar day.
The calendar day limit may be exceeded only in case of operating upsets in refinery units affecting the feed to, or sulfur recovery within, the sulfur block. This allowance extends to a maximum of three calendar days per month.
The sulfur block consists of the sum of emissions from stacks on the refinery's sulfur recovery units, tail gas unit and sulfuric acid regeneration units. The block is a leading source of SO2 emissions at the plant and is considered to be the main contributor to recent exceedances.
"To date, reductions in emissions from the sulfur block have not been sufficient to resolve the exceedances at the Paper Mill Pond ambient monitoring site," said Environment and Local Government Minister Brenda Fowlie. "Therefore, Irving Oil must provide the department with details related to equipment to be installed to alleviate exceedances at the Paper Mill Pond, and provide a plan by May 31, 2005, stating how they propose to reduce emissions to the levels stated in their 1998 Environment Impact Assessment (EIA) Registration." (The stated level at that time was 3,000 kg per day.)
The amendment also requires the company to install a permanent ambient SO2 monitor and weather tower on Midwood Avenue by June 15, 2005, and maintain a temporary air quality monitor until the permanent one is in place. Under specified adverse conditions capable of resulting in SO2 emissions above permitted levels, the company will be required to use ultra-low-sulfur fuel oil in all the refinery's oil-fired units. In addition, Irving must ensure that, within sustainable limits, the feed to the tail gas unit is maximized so as to minimize SO2 emissions from the sulfur block.
The company is further required to submit to the department design details related to the air dispersion capability to be added to each sulfur recovery unit stack. The submission must include studies outlining the expected improvements in dispersion and reductions in ambient concentrations. Air dispersion capability is to be added to each sulfur recovery unit stack, in accordance with the design details, by November 30, 2005.
Notwithstanding the discussions that preceded the issuing of the amendment, the department notes that the renewal of the facility's air quality approval, which expires on September 30, 2005, will still be subject to a public participation process. Last week, Fowlie launched the 180-day public review process for the renewal. It includes a 120-day comment period running from March 31 to July 29, 2005. More information is available on-line at www.gnb.ca/0009/0355/0005/index-e.asp.