1

**Date:** February

7 , 2013 **Subject:** Environmental and Energy I mpacts for Wool Fiberglass Manufacturing NESHAP

– Proposed RTR Amendments 40 CFR 63, Subpart NNN

– Supplemental Proposal EPA Contract No. EP
- D
- 11
- 084 ; EPA Work Assignment No. 1
- 0 7 RTI Project No. 021 3199 .00 1 .00 7 **From:** Cindy

Hancy Dave Reeves **To:** Susan Fairchild, EPA/OAQPS/SPPD/MMG **I. Introduction**  The purpose of this memorandum is to document the estimated environmental and energy impacts associated with the proposed residual risk and technology review (RTR) amendments to 40 CFR 63, Subpart NNN

- Wool Fiberglass Manufacturing. Secondary impacts include the solid waste, water, wastewater generated and the electricit y required to operate air pollution control devices , a s well as, the resultant greenhouse gas (GHG) emissions from controls or work practices required b y the NESHAP. **II. Water,**  **Wastewater , and Solid Waste**  **Impacts** The EPA estimates that three gas - fired glass

- melting furnaces at wool fiberglass manufacturing facilities will need to install a caustic scrubber to meet the proposed chromium compound emission limit for Subpart NNN. The water required to operate the scrubber and the solid and wastewater generated b y the effluent were c alculated for the three units. The 2010 information collection request, sent to all wool fiberglass manufacturers, requested that facilities provide detailed information for each control device. For scrubbers, facilities were asked to provide gas and water flow rates, liquid to gas ratios, pressure drop, wastewater generation, and several other operating parameters for each of their existing scrubber s . Append ix 1 contains a complete list of all the information EPA requested for scrubbers, however, because t he majorit y of facilities submitted this information as confidential business information (CBI), facility responses are not included in this memo. The EPA compiled these ICR responses, and using the operating parameters (also considered CBI) of the three f urnaces estimated to need caustic scrubbers, estimated the amount of water needed to operate the scrubbers, as well as the wastewater and solid waste that would be generated. The calculated impact estimates are provided in Table 1.2

**Table 1. Estimated Water and Solid Waste Impacts for**  **Caustic Scrubbers**  **on Fur n**  **aces** Impacts per facility Total industry impacts Water flow rate into scrubber (gpm) 1 194 582 Percent of scrubber water from recycled facility wastewater 1 60 60 Total non

- recycled water necessary (gallons per year) 2 41M 123 M Total scrubber effluent rate (gpm) 1 6.1 6.1 Percent scrubber wastewater recycled 1 50 50 Total wastewater generated (gallons per year) 3 1.6M 4.8M Total solid waste collected (lb/yr) 1 468,000 1.4M (1) Estimates from ICR responses . (2) Calculation: 194 (gpm) x 60 (min/hr) x 8760 (hrs/yr) x (100%

- 60%). (3) Calculation: 6.1 (gpm) x 60 (min/hr) x 8760 (hrs/yr) x (100%

- 50%). **III. Energy Impacts and**  **GHG Em**  **issions from Electricity Usage** The amount of electricit y required to operate a control device (i.e., caustic scrubber) was calculated using the information summarized in Table 1. The electricity costs associated with operating a scrubber derive from fan requirements to overcome the pres sure drop in the column, ductwork, and other parts of the control sy stem, and pump requirements to re

- circulate the water. According to the EPA’s Air Pollution Control Cost Manual, fan and pump energy requirements can be calculated by using equation 3
- 1 an d 3

- 2, respectivel y.

Equation 3

- 1

= 1
. 17 10 Equation 3

- 2

= 0
. 746 2
. 52 10 Where Gi is the gas flow rate entering the scrubber, P is the total pressure drop, Li is the liquid flow rate entering the scrubber , P is the pressure of the pump which we assume to be 60 ft of water and e is the efficiency of the device
. The average gas flow rate entering the scrubber for the three furnaces is 26,000 acfm, the average e stimated pressure drop for the scrubber is 9.8 inches of water, and the average estimated liquid flow is 194 gallons per minute. Using equation s 3
- 1 and 3

- 2 and an estimated efficiency of 0.7 for both the pump and the fan , we estimated the energy required to be 43kW h for the fan, and 3kW h for the pump .

= ( 1
. 17 10 ) ( 26 , 000 ) ( 9
. 8 )

0
. 7 = 43 h

= ( 0
. 746 ) ( 2
. 52 10 ) ( 60 ) ( 194 )

0
. 7 = 3 h Assuming operating hours is 8,760 per y ear, the total annual energy required for each scrubber is:
46 h 8 , 760 h = 403 , 000 /3

This results in 1.2 m illion kW h per y ear (1,200 m egawatts ) for all three scrubbers. We used the natural gas emission factor (in kilograms [kg]/MMBtu) from the General Stationary Fuel Combustion Sources subpart (40 CFR part 98, subpart C) of the Greenhouse Gas Reporting Rule (listed in Table 2) to estimate the secondary

emissions for CO 2 , CH 4 , and N 2 O. **Table 2. Emission Factors from**  **General Stationary Fuel Combustion Sources (40 CFR part 98, subpart C)** 
**Fuel Default CH**  **4**

**emission factor (kg CH**  **4 /MM**  **Btu) Default N**  **2 O** 

**emission factor (kg**  **N 2**  **O/MM Btu)**  **Default CO**  **2**

**emission factor**  **(kg C O**  **2 /MM**  **Btu)** Natural Gas 1.0 × 10 −03 1.0 × 10 −04 53.02 Global warming potentials of 1 for CO 2 , 21 for CH 4 , and 310 for N 2 O (from Table A

- 1 to subpart A of part 98) were used to estimate CO 2 equivalent emissions (CO 2 eq). First we converted kWh to MMB tu as follows: 1 , 200 , 000 h 0
. 0034 h = 4 , 100 Using the values in Table 2 we estimated CH 4 , N 2 0, and CO 2 , emissions as 4.1 kg/ yr (9 lb s/ yr ), 0.41 kg/ yr (0.9 lbs/ yr ), and 217,000 kg/ yr (478,000 lbs/yr) , respectivel y. We then calculated the CO 2 eq emissions based o n the global warming potentials above as follows:

= 478 , 000 + 21 9 + ( 310 0
. 9 ) This results in 478, 5 00 lbs CO 2eq per y ear for all three scrubbers.