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MEMORANDUM

TO: Tina Ndoh, U.S. EPA/OAQPS/SPPD

– Minerals and Manufacturing Group

FROM: Eastern Research Group, Inc.

DATE: June 4

, 2014

SUBJECT: Comparison of 40 CFR Part 60, subpart T (Standards of Performance for the

Phosphate Fertilizer Industry: Wet

- Process Phosphoric Acid Plants) and 40 CFR Part 63, subpart AA (National Emission Standards for Hazardous Air Pollution from Phosphoric Acid Manufacturing Plants)

This document presents a general comparison between the applicability, definitions, emi ssion
standards, monitoring and operating requirements , and testing and compliance requirements of

the current NSPS 40 CFR Part 60, subpart T

, and NESHAP 40 CFR Part 63, subpart AA
(hereafter referred to as subpart T

, and subpart AA , respectively)

. Subpart T was last amended on
October 17, 2000 and subpart AA was last amended on April 20, 2006. This document does not
encompass recordkeeping or reporting requirements: each subpart reference s the respective
general provisions.

1.0 PROCESS DESCRIPTIONS FOR PRODUCING PHOSPHORIC ACID

Two process descriptions, the wet

- process and thermal process , are provided in C hapter 8,

Volume I, Fifth Edition of AP 42 1



### . In the wet

- process, beneficiated ground phosphate r o ck is
reacted with sulfuric acid and weak phosp horic acid to produce phosphoric acid and
phosphogypsum, a waste product. In most cases, the phosphoric acid is concentrated in vacuum evaporators. In the thermal process, elemental phosphorus is oxidized to form phosphorus
pentoxide, which is subsequently hydrated to form strong phosphoric acid. Based on industry

response s to the April 2010 Section 114, no facility currently uses the thermal process.

2.0 COMPARISON OF NSPS 40 CFR PART 60, SUBPART T TO NESHAP 40 CFR PART 63, SUBPART AA

The following sections provide a brief comparison of subpart T to subpart AA standards for phosphoric acid manufacturing

.

1 http://www.epa.gov/ttn/chief/ap42/ch08/final/c08s09.pdf

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2.1

. Applicability

Both subpart T and subpart AA apply to wet

- process phosphoric acid (WPPA) manufacturing
operations ; however, subpart AA also applies to superphosphoric acid process lines and purified
acid process lines

. While NSPS 40 CFR Part 60, s ubpart U applies to superphosphoric acid
plants, there does not appear to be any NSPS standards applicable to purified acid process lines

. Because su bpart T only applies to WPPA plants, the remaining sections of this document do not discuss superphosphoric or purified acid process lines. The applicability of each subpart to

W P PA manufacturing is presented in Table 2.1. S ubpart T references design capacity, while
subpart AA applies to major sources.

Table 2.1. Applicability Provisions in 40 CFR Part 60, Subpart T and 40 CFR Part 63, Subpart AA

40 CFR Part 60, Subpart T 40 CFR Part 63, Subpart AA

Each WPPA plant [a] having a design capacity of

more than 15 tons P 2 O 5 feed per calendar day [§60.2 00 (a)] Each phosphoric acid manufacturing plant [§63.600(a)], including the following new or existing affected sources at a phosphoric acid manufacturing plant:

Each WPPA process line [ a] [§63.600(b)(1)]

Each evaporativ e cooling tower [§63.600(b)(2)]

Each phosp hate rock dryer [§63.600(b)(3)]

Each phosphate rock calciner [§63.600(b)(4)]

Does not apply to a new or existing phosphoric acid manufacturing plant this is not a major source [§63.600(c)]

No R&D exemption Includes R&D exemption [ §63.6 00 (d) ]

No SSM exemption Includes SSM exemption [ §63.600 (e) ]
[a] For both subpart T and subpart AA

, requirements apply to reactors, filters, evaporators, and hot wells

. [b] 40 CFR Part 60, subpart U applies to superphosphoric acid plants.



### 2. 2. Definitions

S ubpart T define s a WPPA plant . Subpart AA defines a WPPA process line. Subpart AA also

includes several additional definitions related to WPPA manufacturing

. Refer to Table 2.2 for

details.

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Table 2.2. Definitions in 40 CFR Part 60, Subpart T and 40 CFR Part 63, Subpart AA

40 CFR Part 60 , Subpart T 40 CFR Part 63, Subpart AA

WPPA plant: any facility manufacturing phosphoric acid by reacting phosphate rock and acid. [§60.201(a)] WPPA process line: any process line manufacturing phosphoric acid by reacting phosphate rock and acid. [§63.601]

Definitions in Subpart AA related to WPPA manufacturing n ot in Subpart T

Evaporative cooling tower: an open water recirculating device that uses fans or natural draft to draw or force ambient air through the device to remove heat from process water by direct contact. [§63.601]

Phosphate rock calciner: equipment used to remove moisture and organic matter from phosphate rock through direct or indirect heating. [§63.601]

Phosphate rock dryer: the equipment used to reduce the moisture content of phosphate rock through direct or indirect heating. [§63.601]

Phosphate rock feed: all material entering any phosphate rock dryer or phosphate rock calciner

include moisture and extraneous material as well as the following ore materials: fluorapatite, hydroxylapatite, chlorapatite, and carbonateapatite. [§63.601]



### 2. 3. Standards

Subpart T contains a single standard for total fluorides from a WPPA plant

. Subpart AA contains
total fluoride standards for new and existing WPPA lines

, particulate matter standards for
phosphate rock dryers and calciners , and standards f or evaporative cooling towers

. Refer to

Table 2.3 for details.

Table 2.3. Standards in 40 CFR Part 60, Subpart T and 40 CFR Part 63, Subpart AA

HAP/Pollutant 40 CFR Part 60, Subpart T 40 CFR Part 63, Subpart AA

Existing Sources New Sources

Total Fluorides (lb/ton of equivalent P 2 O 5 feed) Affected Facility:

0. 0 20 [§63.202 (a) ] WP P A Process Line:

0. 0 20 [§63.602(a)] WP P A Process Line:

0.01350 [§63.603(a)]

Particulate Matter (lb/ton of phosphate rock feed) NA Rock Dryer: 0.2150 [§63.602(c)] Rock Dryer: 0.060 [§63.603(c)]

Particulate Matter (gr/dscf) NA Rock Calciner: 0.080 [§63.602(d)] Rock Calciner: 0.040 [§63.603(d)]

None Specified NA Prohibition on introduction of wet scrubber liquid effluent into any evaporative cooling tower. [§63.602(e) and §63.603(e)]

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2.4

. Monitoring and Operating Requirements

The most substantial difference s between subpart T and subpart AA in regards to monitoring and
compliance is related to establishing and adhering to parameter monitoring ranges for wet scrubbing systems. Both subparts include requirements to operate a continuous parameter
monitoring system to record pressure drop, but only subpart AA includes a requirement to
monitor and record the flow rate of scrubbing liquid. Subpart AA also inclu des specific
requirements that facilities must operate within the establish ed parameters : such requirements are
not included in subpart T

. Additionally, s ubpart AA includes specific monitoring requirements
for phosphate rock dryers and calciners: subpart T contains no such requirements. Refer to Table

2.4 for details.

Table 2.4. Monitoring and Operating Requirements in

40 CFR Part 60, Subpart T and 40 CFR Part 63, Subpart AA 40 CFR Part 60, Subpart T 40 CFR Part 63, Subpart AA

P 2 O 5 Feed Accounting

– WPPA Plant/Process Line

 Install, calibrate, maintain, and operate a monitoring device which can be used to determine the mass flow of phos

- bearing feed to process within an accuracy of ±5% over operating range. [§60.2 0 3 (a) ]

 Maintain a daily record of eq. P 2 O 5 feed according to procedures in subpart. [§60.2 0 3 (b) ]  Install, calibrate, maintain, and operate a monitoring

device which can be used to determine and permanently record the mass flow of phos

- bearing feed to process within an accuracy of ±5% over operating range. [§63.6 0 5(a) (1) ]

 Maintain a daily record of eq. P 2 O 5 feed according to procedures in subpart. [§63.6 0 5(b) (1) ]

P 2 O 5 Feed Accounting

–

Rock Dryer/Rock Calciner

 NA  Install, calibrate, maintain, and operate a monitoring

device which can be used to determine and permanently record either the mass flow of phos

bearing feed to the dryer/calciner, or the mass flow of product from the dryer/calciner within an accuracy of

± 5% over operating range. [§63.605(a)(2)]

 Maintain a daily record of phosphate rock feed or product (depending on monitoring choice) using the monitoring system which meets the requirements of §63.605(a)(2). [§63.605(b)(2) Scrubbing Systems Install, calibrate, maintain, and operate a monitoring device which continuously measures and permanently records the total pressure drop across the process scrubbing
system (accuracy of ± 5% over operating range). [§60.2 0 3 (c) ] Install, calibrate, maintai n, and operate a monitoring system which continuously measures and permanently

records: A) the pressure drop across [§63.6 0 5(c)(1)] , and B) the flow rate of scrubbing liquid to [§63.6 0 5(c)(2)]

,

Each scrubber in the process scrubbing system in

15

- min block averages (accuracy of ± 5% over operating range). [§63.6 0 5(c) (1) and (c)(2) ]

Establish allowable ranges, maintain daily averages within the established ranges, for pressure drop and flow rate. [§63.6 0 4 and §63.6 0 5( d )]

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2.5

. Testing and Compliance

The testing and compliance requirements vary in frequency and method between subpart T and
subpart AA

. Subpart T only requires an initial performance test, whereas subpart AA requires
initial and annual testing. Subpart AA also allows facilities a broader choice of test methods than
subpart T in determining P 2 

### O 5 

### content of feed.

Table 2.5. Testing and Compliance in 40 CFR Part 60, Subpart T and 40 CFR Part 63, Subpart AA

40 CFR Part 60, Subpart T 40 CFR Part 63, Subpart AA Frequency of Performance Test

Within 60 days of max production rate, but no later than 180 days after initial startup [§60.8] Existing Sources : On or before applicable compliance

date and then annually

. [§63.6 0 6(a)(1)]

New Sources: Within 180 days of compliance date and

then annually

. [§63.6 0 6(a)(2)] Sampling and Analysis Methods

Total Fluorides: Method 13A or 13B with at
least a 60 minute sampling time and

0.85 dscm (30 dscf) sample volume. [§60.2 0 4(b)(2)]

P 2 O 5 Content of Feed : The Association of Official Analytical Chemists (AOAC) Method

9. [§60.2 04(b)(3)(ii) ] Total Fluorides: Method 13A or 13B with a t least a

60 minute sampling time and 0.85 dscm (30 dscf) sample volume. [§63.6 0 6(c)(2)]

Particulate Matter: Method 5 (40 CFR part 60, appendix A) with at least a 60 minute sample time and 0.85 dscm (30 dscf) sample volume for rock dryers and

a 1.70 dscm sam

pl e volume for rock calciners. [§§63.606(d)(2) and 63.606(e)(1)]

P 2 O 5 Content of Feed: Various methods fro m t he Association of Florida Phosphate Chemists, Seventh

Edition 1991

. [§63.60 6(c ) (3) (ii) ]