(a) In accordance with the compliance schedule in §117.9320 of this title (relating to Compliance Schedule for Cement Kilns), the owner or operator of each portland cement kiln shall ensure that nitrogen oxides (NOX ) emissions do not exceed the following rates on a 30-day rolling average. For the purposes of this section, the 30-day rolling average is calculated as the total of all the hourly emissions data (in pounds) that fuel was combusted in a cement kiln in the preceding 30 consecutive days, divided by the total number of tons of clinker produced in that kiln during the same 30-day period:
  (1) for each long wet kiln:
    (A) in Bexar, Comal, Hays, and McLennan Counties, 6.0 pounds per ton (lb/ton) of clinker produced; and
    (B) in Ellis County, 4.0 lb/ton of clinker produced;
  (2) for each long dry kiln, 5.1 lb/ton of clinker produced;
  (3) for each preheater kiln, 3.8 lb/ton of clinker produced; and
  (4) for each preheater-precalciner or precalciner kiln, 2.8 lb/ton of clinker produced.
(b) If there are multiple cement kilns at the same account, the owner or operator may choose to comply with the emission specifications of subsection (a) of this section on the basis of a weighted average for the cement kilns at the account that are subject to the same specification. Each owner or operator choosing this option shall submit written notification of this choice to the executive director, the appropriate regional office, and any local air pollution control program with jurisdiction before the appropriate compliance date in §117.9320 of this title.
(c) Each long wet or long dry kiln for which the following controls are installed and operated during kiln operation is not required to meet the NOX emission specifications of subsection (a) of this section, provided that each owner or operator choosing this option submits written notification of this choice to the executive director, the appropriate regional office, and any local air pollution control program with jurisdiction before the appropriate compliance date in §117.9320 of this title:
  (1) a low-NOX burner and either:
    (A) mid-kiln firing; or
    (B) some other form of secondary combustion achieving equivalent levels of NOX reductions; or alternatively;
  (2) other additions or changes to the kiln system achieving at least a 30% reduction in NOX emissions, provided the additions or changes are approved by the executive director with concurrence from the United States Environmental Protection Agency.
(d) Each preheater or precalciner kiln for which either a low-NOX burner or a low-NOX precalciner is installed and operated during kiln operation is not required to meet the NOX emission specifications of subsection (a) of this section. Each owner or operator choosing this option shall submit written notification of this choice to the executive director, the appropriate regional office, and any local air pollution control program with jurisdiction before the appropriate compliance date in §117.9320 of this title.
(e) An owner or operator may use §117.9800 of this title (relating to Use of Emission Credits for Compliance) to meet the NOX emission control requirements of this section, in whole or in part.
(f) This section no longer applies in Bexar County after December 31, 2024.

Source Note: The provisions of this §117.3110 adopted to be effective June 14, 2007, 32 TexReg 3206; amended to be effective May 16, 2024, 49 TexReg 3347