Section 112.43 - Calculation Methods(a) Application. Determination of the net ground level concentration shall be performed in accordance with the procedures outlined in § 112.33 of this title (relating to Calculation Methods) for hydrogen sulfide and this section for sulfuric acid (H[sub]2[/sub]SO[sub]4[/sub]).(b) Determination of compliance with emission limits. In most cases downwind samples will suffice; however, if the sampled properties are suspected of being influenced by an upwind source of H[sub]2[/sub]SO[sub]4[/sub], then both upwind and downwind samples will be taken. The concentration of H[sub]2[/sub]SO[sub]4[/sub] in the downwind sample less the concentration in the upwind sample shall be used in determining whether the emissions from the property comply with the requirements of § 112.41 of this title (relating to Allowable Emissions). Calculated maximum allowable emission rates or ground level concentrations which are obtained by the method in subsection (c) of this section may be used in determining whether a property is in compliance with the emission limits specified.(c) Calculations of H[sub]2[/sub]SO[sub]4[/sub] concentrations from stack samples and measurements. The maximum allowable H[sub]2[/sub]SO[sub]4[/sub] emission rate which may be made from a stack on property to comply with the emission limit set forth in § 112.41 of this title (relating to Allowable Emissions) may be calculated by Sutton's equation which has been modified to consider the critical wind speed and to correspond to a one-hour sample. Additional credit on stack emissions can be obtained if the distance from the stack to the property line is greater than 30 stack heights. Those properties with greater than 30 stack heights to the property line should contact the executive director to obtain the proper correction factor. (1) For exit stack gas for temperatures of less than 125 degrees Fahrenheit. The following calculations shall be used for exit stack gas for temperatures of less than 125 degrees Fahrenheit. (A) The H[sub]2[/sub]SO[sub]4[/sub] ambient air level of 80 ug/M[sup]3[/sup] for one hour is used. Attached Graphic
(2) For exit stack gas for temperature greater than 125 degrees Fahrenheit. The following calculations shall be used for exit stack gas for temperatures greater than 125 degrees Fahrenheit. (A) The H[sub]2[/sub]SO[sub]4[/sub] ambient air level of 80 ug/M[sup]3[/sup] for one hour is used. Attached Graphic
(B) To plot Graph V, assume a basic stack height of 100 feet and an exit velocity of 20 feet/second. Let stack gas temperature vary with stack diameter.(3) Examples. The following are examples of stack emission calculations. (A) Example 1. (Temperature of stack gas less than 125 degrees Fahrenheit.) How many pounds/hour of H[sub]2[/sub]SO[sub]4[/sub] can be discharged from a 200 foot stack having a four foot exit diameter (ID) and a 30 feet/second exit gas velocity? The temperature of the exit gases is 100 degrees Fahrenheit. Solution.(i) The ratio of stack diameter to 100 feet is 4/100 = 0.04.(ii) Enter ordinate of Graph IV with 0.04; go horizontally to intersection of 30 feet/second velocity curve. At this intersection read on the abscissa 17 pounds/hour. This is the permitted value for a 100 foot stack.(iii) Correct emissions for a 200 foot stack. Enter Graph I at 200 feet and obtain correction factor of 2.3. Thus the emissions become 17 x 2.3 = 39 pounds/hour.(B) Example 2. (Temperature of stack gas greater than 125 degrees Fahrenheit.) How many pounds/hour of H[sub]2[/sub]SO[sub]4[/sub] can be discharged from a 200 foot stack having a four foot exit diameter (ID) and a 30 feet/second exit gas velocity? The temperature of the exit gases is 400 degrees Fahrenheit. Solution. (i) Enter ordinate of Graph V with 400; go horizontally to intersection of four foot diameter and read on abscissa 26 pounds/hour emission. This is the permitted value for a 100 foot stack and exit velocity of 20 feet/second.(ii) Correct for stack height. Thus, 200/100 = 2. We now have 26 x 2 = 52 pounds/hour.(iii) Correct for stack exit velocity of 30 feet/second. This is a direct ratio and becomes 30/20 = 1.5. The emission now is 52 x 1.5 = 78 pounds/hour. Attached Graphic
30 Tex. Admin. Code § 112.43
The provisions of this §112.43 adopted to be effective July 14, 1989, 14 TexReg 3203.