Section NR 440.24 - Sulfuric acid plants(1) APPLICABILITY AND DESIGNATION OF AFFECTED FACILITY.(a) The provisions of this section are applicable to each sulfuric acid production unit, which is the affected facility.(b) Any facility under par. (a) that commences construction or modification after August 17, 1971, is subject to the requirements of this section. (2) DEFINITIONS. As used in this section, terms not defined in this subsection have the meanings given in s. NR 440.02. (a) "Acid mist" means sulfuric acid mist, as measured by Method 8 of 40 CFR part 60, Appendix A, incorporated by reference in s. NR 440.17, or an equivalent or alternative method.(b) "Sulfuric acid production unit" means any facility producing sulfuric acid by the contact process by burning elemental sulfur, alkylation acid, hydrogen sulfide, organic sulfides and mercaptans or acid sludge, but does not include facilities where conversion to sulfuric acid is utilized primarily as a means of preventing emissions to the atmosphere of sulfur dioxide or other sulfur compounds.(3) STANDARD FOR SULFUR DIOXIDE. (a) On and after the date on which the performance test required to be conducted by s. NR 440.08 is completed, no owner or operator subject to the provisions of this section may cause to be discharged into the atmosphere from any affected facility any gases which contain sulfur dioxide in excess of 2.0 kg per metric ton of acid produced (4.0 lb per ton), the production being expressed as 100% H2SO4.(4) STANDARD FOR ACID MIST. (a) On and after the date on which the performance test required to be conducted by s. NR 440.08 is completed, no owner or operator subject to the provisions of this section may cause to be discharged into the atmosphere from any affected facility any gases which: 1. Contain acid mist, expressed as H2SO4, in excess of 0.075 kg per metric ton of acid produced (0.15 lb per ton), the production being expressed as 100% H2SO4.2. Exhibit 10% opacity, or greater.(5) EMISSION MONITORING. (a) A continuous monitoring system for the measurement of sulfur dioxide shall be installed, calibrated, maintained and operated by the owner or operator. The pollutant gas used to prepare calibration gas mixtures under Performance Specification 2 of 40 CFR part 60, Appendix B, incorporated by reference in s. NR 440.17, and for calibration checks under s. NR 440.13(4) shall be sulfur dioxide (SO2). Method 8 of 40 CFR part 60, Appendix A, incorporated by reference in s. NR 440.17, shall be used for conducting monitoring system performance evaluations under s. NR 440.13(3), except that only the sulfur dioxide portion of the Method 8 results shall be used. The span value shall be set at 1000 ppm of sulfur dioxide.(b) The owner or operator shall establish a conversion factor for the purpose of converting monitoring data into units of the applicable standard (kg/metric ton, lb/ton). The conversion factor shall be determined, at a minimum, 3 times daily by measuring the concentration of sulfur dioxide entering the converter using suitable methods (e.g., the Reich test, National Air Pollution Control Administration Publication No. 999-AP-13) and calculating the appropriate conversion factor for each 8-hour period as follows: See PDF for diagram
where:
CF is the conversion factor (kg/metric ton per ppm, lb/ton per ppm)
k is the constant derived from material balance. For determining CF in metric units, k = 0.0653. For determining CF in English units, k = 0.1306.
r is the percentage of sulfur dioxide by volume entering the gas converter. Appropriate corrections must be made for air injection plants subject to the department's approval.
s is the percentage of sulfur dioxide by volume in the emissions to the atmosphere determined by the continuous monitoring system required under par. (a).
(c) The owner or operator shall record all conversion factors and values under par. (b) from which they were computed (i.e., CF, r, and s).(d) Alternatively, a source that processes elemental sulfur or an area that contains elemental sulfur and uses air to supply oxygen may use the following continuous emission monitoring approach and calculation procedures in determining SO2 emission rates in terms of the standard. This procedure is not required but is an alternative that would alleviate problems encountered in the measurement of gas velocities or production rate. Continuous emission monitoring systems for measuring SO2, O2 and CO2, if required, shall be installed, calibrated, maintained and operated by the owner or operator and subjected to the certification procedures in Performance Specifications 2 and 3 in Appendix B, 40 CFR part 60, incorporated by reference in s. NR 440.17(1). The calibration procedure and span value for the SO2 monitor shall be as specified in par. (b). The span value for CO2, if required, shall be 10% and for O2 shall be 20.9% (air). A conversion factor based on process rate data is not necessary. Calculate the SO2 emission rate as follows: See PDF for diagram
where:
Es is the SO2 emission rate in kg/metric ton (lb/ton) of 100% of H2SO4 produced
Cs is the concentration of SO2, kg/dscm (lb/dscf) (see the table in the note following this paragraph)
S is the acid production rate factor, 368 dscm/metric ton (11,800 dscf/ton) of 100% H2SO4 produced
%O2 is the oxygen concentration, percent dry basis
A is the auxiliary fuel factor,
= 0.00 for no fuel
= 0.0226 for methane
= 0.0217 for natural gas
= 0.0196 for propane
= 0.0172 for #2 oil
= 0.0161 for #6 oil
= 0.0148 for coal
= 0.0126 for coke
%CO2 is the carbon dioxide concentration, percent dry basis
Note: It is necessary in some cases to convert measured concentration units to other units for these calculations. Use the following table for such conversions:
| From | To | Multiply by |
| 1. | g/scm | kg/scm | 10-3 |
| 2. | mg/scm | kg/scm | 10-6 |
| 3. | ppm (SO2) | kg/scm | 2.660 X 10-6 |
| 4. | ppm (SO2) | lb/scm | 1.660 X 10-7 |
(e) For the purpose of reports under s. NR 440.07(3), periods of excess emissions shall be all 3-hour periods (or the arithmetic average of 3 consecutive 1-hour periods) during which the integrated average sulfur dioxide emissions exceed the applicable standards under sub. (3).(6) TEST METHODS AND PROCEDURES. (a) In conducting the performance tests required in s. NR 440.08, the owner or operator shall use as reference methods and procedures the test methods in Appendix A of 40 CFR part 60, incorporated by reference in s. NR 440.17, or other methods and procedures as specified in this subsection, except as provided in s. NR 440.08(2). Acceptable alternative methods and procedures are given in par. (c).(b) The owner or operator shall determine compliance with the SO2 acid mist, and visible emission standards in subs. (4) and (5) as follows: 1. The emission rate (E) of acid mist or SO2 shall be computed for each run using the following equation: E = (CQsd)/(PK)
where:
E is the emission rate of acid mist or SO2 kg/metric ton (lb/ton) of 100% H2SO4 produced
C is the concentration of acid mist or SO2, g/dscm (lb/dscf)
Qsd is the volumetric flow rate of the effluent gas, dscm/hr (dscf/hr)
P is the production rate of 100% H2SO4, metric ton/hr (ton/hr)
K is the conversion factor, 1000 g/kg (1.0 lb/lb)
2. Method 8 shall be used to determine the acid mist and SO2 concentrations (C's) and the volumetric flow rate (Qsd) of the effluent gas. The moisture content may be considered to be zero. The sampling time and sample volume for each run shall be at least 60 minutes and 1.15 dscm (40.6 dscf).3. Suitable methods shall be used to determine the production rate (P) of 100% H2SO4 for each run. Material balance over the production system shall be used to confirm the production rate.4. Method 9 and the procedures in s. NR 440.11 shall be used to determine opacity.(c) The owner or operator may use the following as alternatives to the reference methods and procedures specified in this subsection:1. If a source processes elemental sulfur or an ore that contains elemental sulfur and uses air to supply oxygen, the following procedure may be used instead of determining the volumetric flow rate and production rate:a. The integrated technique of Method 3 is used to determine the O2 concentration and, if required, CO2 concentration.b. The SO 2 or acid mist emission rate is calculated as described in sub. (5) (d), substituting the acid mist concentration for Cs as appropriate.Wis. Admin. Code Department of Natural Resources NR 440.24
Cr. Register, January, 1984, No. 337, eff. 2-1-84; cr. (5) (d) and (6) (e), Register, September, 1986, No. 369, eff. 10-1-86; am. (2) (intro.) and (3) (a), Register, September, 1990, No. 417, eff. 10-1-90; am. (5) (a) and (b), r. and recr. (5) (d) and (6), Register, July, 1993, No. 451, eff. 8-1-93; cr. (5) (e), Register, December, 1995, No. 480, eff. 1-1-96; CR 06-109: am. (5) (d) Register May 2008 No. 629, eff. 6-1-08.