### 1

MEMORANDUM

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

– Minerals and Manufacturing Group

FROM: Eastern Research Group, Inc.

DATE: June 9 , 2014

SUBJECT: Comparison of 40 CFR Part 60, subpart W and subpart X (Standards of

Performance for the Phosphate Fertilizer Industry: Triple Superphosphate Plants and Granular Triple Superphosphate Storage Facilities) and 40 CFR Part 63, subpart BB (National Emission Standards for Hazardous Air Pollution from Phosphate Fertilizers Production Plants)

This document pr esents a general comparison between the applicability, definitions, emission
standards, monitoring and operating requirements , and testing and compliance requirements of

NSPS 40 CFR Part 60, subpart W and subpart X

, and NESHAP 40 CFR Part 63, subpart BB
(hereafter referred to as subpart W , subpart X

, and subpart BB, respectively)

. Subparts W and X
were last amended on October 17, 2000 and subpart BB was last amended on April 20, 2006.
This document does not encompass recordkeeping or reporting requiremen ts: each subpart

reference s the respective general provisions.

1.0 PROCESS DESCRIPTIONS FOR PRODUCING TRIPLE SUPERPHOSPHATE
(TSP)

Two process descriptions, run

- of

- the

- pile

- TSP (ROP

- TSP) and granular TSP (GTSP), are provided in chapter 8, Volume I, Fifth Edition of AP 42. It is noted in AP 42 that no U.S.
facilities are currently producing ROP

- TSP. From Section 8.5.2.2 1 

### :

The ROP

- TSP material is essentially a pulverized mass of variable particle size produced in a manner similar to normal superphosphate. Wet

- process phosphoric acid (50 to 55 percent P 2 

### O 5 

### ) is reacted with ground phosphate rock in a cone mixer. The resultant slurry begins to solidify on a slow moving c onveyer en route to the curing area. At the poin t of discharge from the den, the material passes through a rotary mechanical cutter that breaks up the solid mass. Coarse ROP

- TSP product is sent to a storage pile and cured for 3 to 5 weeks. The product is then mined from the storage pile

to be crushed, s creened, and shipped in bulk.

GTSP yields larger, more uniform particles with improved storage and handling properties. Most of this material is made with the Dorr

- Oliver slurry granulation

1 http://www.epa.gov/ttnchie1/ap42/ch08/final/c08s05

- 2.pdf

### 2

process, illustrated in Figure 8.5.2

- 1. In this process, ground p hosphate rock or limestone is reacted with phosphoric acid in 1 or 2 reactors in series. The phosphoric acid used in this process is appreciably lower in concentration (40 percent P 2 

### O 5 

### ) than

that used to manufacture ROP

- TSP product. The lower strength acid maintains the slurry in a fluid state during a mixing period of 1 to 2 hours. A small sidestream of slurry is continuously removed and distributed onto dried, recycled fines, where it coats the granule surfaces and builds up its size

.

Slurry

- wetted g ranules are then discharged onto a rotary dryer, where excess water is evaporated and the c hemical reaction is accelerated to completion by the dryer heat. Dried granules are then sized on v ibrating screens. Oversize particles are crushed and

re

- circulated to the screen, and undersize particles are recycled to the granulator.

Product

- size granules are cooled in a countercurrent rotary drum, then s ent to a storage pile for curing. After a curing period of 3 to 5 days, granules are removed from storage,

scree ned, bagged, and shipped.

2.0 COMPARISON OF NSPS 40 CFR PART 60, SUBPART W AND SUBPART X TO
NESHAP 40 CFR PART 63, SUBPART BB

The following sections provide a brief comparison of subpart W and s ubpart X to subpart BB

standards for TSP.

2.1

. Applicabil ity

Both subpart W and subpart BB apply to TSP production ; however, subpart BB only applies to

the production and storage of GTSP (see Table 2.1a) . Subpart W appears to apply to both ROP

TSP and GTSP production as 40 CFR 60.230(a) reads “...the provisions of this subpart appl[ies
to] each triple superphosphate plant...” However, s ubpart W excludes the storage of GTSP as 40
CFR 60.230 only addresses ROP

- TSP in regards to product storage. Storage of GTSP is covered
under subpart X (see Table 2.1b)

.

Table 2.1a. Applicability Provisions in 40 CFR Part 60, Subpart W and

40 CFR Part 63, Subpart BB 40 CFR Part 60, Subpart W 40 CFR Part 63, Subpart BB

Each TSP plant [a] w/ design capacity >15 tons P 2 O 5 feed per day [§60.230(a)] and facilities which store

ROP

- TSP [§60.230(b)] Each new or existing GTSP process line [a] at a major source [§63.620(a)(2) and §63.620(c)]

No R&D exemption Includes R&D exemption [ §63.620(d) ]

No SSM exemption Includes SSM exemption [ §63.620(e) ]
[a] For both subpart W and subpart BB, requirements apply to : mixers, curing belts (dens), reactors, granulators, dryers, coolers 2

, screens, and mills.

2 Listed as “cookers” in §60.230(a): the term “cookers” (as opposed to coolers) is assumed to be a typographical error as background literature and ERG’s knowledge of industry does not indicate any equipment referred to “cookers” being used in the manufacture of TSP.

### 3 Table 2.1b. Applicability Provisions i n 40 CFR Part 60, Subpart X and

40 CFR Part 63, Subpart BB 40 CFR Part 60, Subpart X 40 CFR Part 63, Subpart BB

Each GTSP storage facility [ a] [§60.240(a)] Each new or existing GTSP storage building [ a ] at a major source [§63.620(a)(2) and §63.620(c)]

No R&D exemption Includes R&D exemption [§63.620(d)]

No SSM exemption Includes SSM exemption [§63.620(e)]

[ a ] The following emission points are listed as components of G TSP storage: storage or curing buildings (noted as “piles” in
subpart x) , conveyors, elevators, screens and mills.



### 2. 2. Definitions

The differences in applicability presented in Section 2. 1 are reflected in the definitions for each
subpart. Subpart W generally defines a TSP plant (without regard to run

- of

- pile or granular) and

ROP

- TSP, but not GTSP. Refer to Table 2.2a for details.

Table 2.2a. Definitions in 40 CFR Part 60, Subpart W and 40 CFR Part 63, Subpart BB

40 CFR Part 60 , Subpart W 40 CFR Part 63, Subpart BB TSP plant: any facility manufacturing TSP by reacting phosphate rock with phosphoric acid. A

run

- of

- pile TSP plant includes curing and storing.
[ §60.231(a) ]

ROP

- TSP: any TSP that has not been processed in a granulator and is composed of particles at least 25% by weight of which (when not caked) will pass thr ough a 16 mesh screen. [§60.231(b)] G TSP process line: any process line, not including storage buildings, manufacturing granular TSP by reacting phosphate rock with phosphoric acid.
[ §63.621 ]



### In subpart X and subpart BB, only GTSP and GTSP related terms are defined. Refer to Table

2.2b for details.

Table 2.2b. Definitions in 40 CFR Part 60, Subpart X and 40 CFR Part 63, Subpart BB 40 CFR Part 60, Subpart X 40 CFR Part 63, Subpart BB Fresh GTSP: granular TSP produced within the preceding 72 hours [§60.241(d)] Fresh GTSP: granular TSP produced within the preceding 72 hours. [§63.621] GTSP storage facility : any facility curing or storing

fresh GTSP [§60.241(a)] GTSP storage building : any building curing or storing fresh GTSP. [§63.621]



### 2. 3. Total Fluorides Standards

The total fluorides standards differ in both magnitude and applicability between subpart W and
subpart BB. Subpart BB includes separate standards for GTSP process lines and storage
buildings , whereas Subpart W contains a single numeri cal emission limit, but does not
differentiate between production/process lines and storage. Refer to Table 2.3a for details.

### 4 Table 2.3 a. Total Fluorides Standards in 40 CFR Part 60, Subpa rt W and

40 CFR Part 63, Subpart BB

40 CFR Part 60, Subpart W 40 CFR Part 63, Subpart BB Existing Sources New Sources Production and Storage: [a]
100 g/Mg of equivalent P 2 O 5 feed (0.20 lb/ton) [§63.232] Process Line: 75 g/metric ton of equivalent P 2 O 5 feed (0.150 lb/ton)
[ § 63.622(b) ] Process Line: 61.5 g/metric ton of equivalent P 2 O 5 feed (0.1230 lb/ton) [ §63.623(b) ] No prohibition on shipping Prohibition on shipping fresh GTSP [ §63.622(c)(2) and §63.623(c)(2) ]

[a] The single numerical emission limit in subpart W applies to production of ROP

- TSP and GTSP and the storage of ROP

- TSP,
based on the applicability provisions in 40 CF R 60.230 (refer to Section 2.1)

.



### Subpart X and subpart BB contain an equivalent numerical emission limit for total fluorides.
Additionally, subpart X and subpar t BB both include a provision prohibiting the shipment of
fresh GTSP. No such provision is contained in subpart W for the shipment of ROP

- TSP. Refer to

Table 2.3b for details.

Table 2.3 b. Total Fluorides Standards in 40 CFR Part 60, Subpart X and

40 CFR P art 63, Subpart BB

40 CFR Part 60, Subpart X 40 CFR Part 63, Subpart BB New and Existing Sources Storage Facility: 0.250 g/hr/metric ton of equivalent P 2 O 5 stored (5.0x10

- 4 lb/hr/ton) [§63.242(a)] Storage Building: 0.250 g/hr/metric ton of equivalent P 2 O 5 stored (5.0x10

- 4 lb/hr/ton) [§63.622(c)(1) and §63.623(c)(1)]

Prohibition on shipping fresh GTSP [§63.242(b)] Prohibition on shipping fresh GTSP [§63.622(c)(2) and §63.623(c)(2)]



### 2.4

. Monitoring and Operating Requirements

The most substantial difference between subpart s W and X and subpart BB in regards to
monitoring and compliance is related to establishing and adhering to parameter monitoring
ranges for wet scrubbing systems. All three subparts include requirements to operate a
continuous par ameter monitoring system to record pressure drop, but only subpart BB includes a
requirement to monitor and record the flow rate of scrubbing liquid. Subpart BB also includes
specific language that facilities must operate within the establish parameters, w hereas such
language is not included in subpart W or subpart X

. Subpart X and s ubpart BB also includes
requirements to maintain an account of GTSP in storage , but subpart W does not include any
storage accounting requirements. Refer to Tables 2.4a and 2.4b for details.

Table 2.4a. Monitoring and Operating Requirements in 40 CFR Part 60, Subpart W and 40 CFR Part 63, Subpart BB 40 CFR Part 60, Subpart W 40 CFR Part 63, Subpart BB

P 2 O 5 Feed Accounting

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

- bearing  Install, calibrate, maintain, and operate a monitoring

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

- bearing

### 5 Table 2.4a. Monitoring and Operating Requirements in 40 CFR Part 60, Subpart W and 40 CFR Part 63, Subpart BB 40 CFR Part 60, Subpart W 40 CFR Part 63, Subpart BB feed to process within an accuracy of ±5% over operating range. [§60.233]

 Maintain a daily record of eq. P 2 O 5 feed according to proc edures in subpart. [§60.233] feed to process within an accuracy of ±5% over operating range. [§63.625(a)]

 Mai ntain a daily record of eq. P 2 O 5 feed according to procedures in subpart. [§63.625(b)]

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). [§60.233] Install, calibrate, maintain, and operate a monitoring system which continuously measures and permanently

records:

A) the pressure drop across [§63.625(c)(1)] , and

B) the flow rate of scrubbing liquid to [§63.625(c)(2)]

,

Each scrubber in the process scrubbing system in 15

- min block averages (accuracy of ± 5% over operating range). [§63.625(c)(2)]

Establish allowable ranges, maintain daily averages

within the established ranges, for pressure drop and flow rate. [§63.624 and §63.625(f)]

Table 2.4b. Monitoring and Operating Requirements in 40 CFR Part 60, Subpart X and 40 CFR Part 63, Subpart BB 40 CFR Part 60, Subpart X 40 CFR Part 63, Subpart BB Product Storage Accounting

 Maintain an accurate account of TSP in storage to permit the determination of the amount of eq. P 2 O 5 stored. [§60.243(a)]

 Maintain a daily record of eq. P 2 O 5 stored according to procedures in subpart. [§60.243(b)]  Maintain an accurate account of TSP in storage to permit the determination of the amount of eq. P 2 O 5 stored. [§63.625(d)]

 Maintain a daily record of eq. P 2 O 5 stored according to procedures in subpart. [§63.625(e)(1)]

Scrubbing Systems

Install, calibrate, maintain, and operate a monitoring device which continuously measures and permanently records the total pressure drop across any process scrubbing

system (accuracy of ± 5% over operating range). [§60.243(c)] Install, calibrate, maintai n, and operate a monitoring system which continuously measures and permanently

records:

A) the pressure drop across [§63.625(c)(1)], and

B) the flow rate of scrubbing liquid to [§63.625(c)(2)]

,

Each scrubber in the process scrubbing system in 15

- min block averages (accuracy of ± 5% over operating range). [§63.625(c)(2)]

### 6 Table 2.4b. Monitoring and Operating Requirements in 40 CFR Part 60, Subpart X and 40 CFR Part 63, Subpart BB 40 CFR Part 60, Subpart X 40 CFR Part 63, Subpart BB

Establish allowable ranges, maintain daily averages within the established ranges, for pressure drop and flow rate. [§63.624 and §63.625(f)]



### 2.5

. Testing and Compliance

The testing and compliance requirements vary in frequency and method between subpart W and
subpart X, and subpart BB. Subpart W and subpart X only require an initial performance test,
whereas subpart BB requires initial and annual testing. Subpart BB also allo ws facilities a
broader choice of test methods than subpart W and subpart X in determining P 2 

### O 5 

### content of
feed and product stored.

Subpart X and subpart BB are identical in restrictions regarding the testing of GTSP storage
buildings in relation to the a mount of GTSP being stored. Refer to Table 2.5 for details.

Table 2.5. Testing and Compliance in 40 CFR Part 60, Subparts W and X, and 40 CFR Part 63, Subpart BB

40 CFR Part 60, Subpart s W and X 40 CFR Part 63, Subpart BB 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

. [§63.626(a)(1)]

New Sources: Within 180 days of compliance date and

then annually

. [§63.626(a)(2)] Sampling and Analysis Methods

Total Fluorides: Method 13A or 13B with 60 minute sampling time and 0.85 dscm (30 dscf) sample volume. [§60.234(b)(2) and §60.244(c)(2)]

P 2 O 5 Content of Feed and Product
Stored [a] : The Association of Official Analytical Chemists (AOAC) Method 9. [§60.234(b)(3)(ii) and §60.244(c)(3)(ii)] Total Fluorides: Method 13A or 13B with a 1 hour sampling time and 0.85 dscm (30 dscf) sample volume. [§63.626(c)(2)]

P 2 O 5 Content of Feed and Product Stored : Various

methods from t he Association of Florida Phosphate Chemists, Seventh Edition 1991 and the Official Methods of Analysis of AOAC International, sixteenth Edition, 1995. [§63.626(c) and (d)]

[a] Storage only applies to subpart X.