PERMIT REVIEW SUMMARY

Permit Writer:	Clinton Gentry 					Date:	July 16, 2021

Company Name:	GX Technologies LLC

Facility Location:	Plant Road off of Lower Woodville Road
			Natchez, MS

			31º 30’ 56” N
			91º 25’ 08” W

Source Number:	0040-00062

County: 		Adams

FACILITY DESCRIPTION

GX Technologies LLC, is classified as an establishment primarily engaged in manufacturing industrial inorganic chemicals under SIC Code 2819 and NAICS 325180.

GX Technologies has applied for an Air Construction Permit as well as a True Minor Determination for their proposed pilot plant located in Natchez, MS. The facility’s primary function is the production of Graphene Oxide (GO) via the oxidation of graphite flakes. The facility has the following emission points: one (1) baghouse, two (2) points of graphene oxide process vents, one (1) adsorption unit, one (1) offgas scrubber, eleven (11) miscellaneous storage tanks, one (1) cooling tower, one (1) space heater, and fugitive equipment leaks.

The proposed facility will be a pilot plant designed to produce 13 lbs of GO per batch and 172 batches per year for a total annual production of 2,236 lbs. per year. Initial production of GO will be with smaller reactors designed for approximately 1.3 pounds of production per batch to allow for the collection of basic data on a smaller scale. The overall Graphene Oxide process consists of the following process steps: graphite size reduction, preliminary GO generation, GO cooling, GO purification, phase separation 1, GO product washing, phase separation 2, GO coagulation, phase separation 3, and phase separation 4. All the GO processing equipment and acid storage tanks are vented to an acid fume scrubber, which utilizes Sodium Hydroxide (NaOH) as a neutralizing agent, to remove acid vapors. All the liquid waste streams from the process are sent to a Caustic Neutralization System, which utilizes NaOH to remove any potential acid residue.

GX Technologies will be located within the same plant boundary as PowerChem Inc. (AI 79314) and as such, the two facilities will be considered adjacent to one another. While the two facilities will have two separate permits, they will be considered as one emission source and their combined emissions will determine the emission limits for both facilities.

EMISSION SUMMARY

Criteria Pollutant	GX Technologies Maximum Uncontrolled1	PowerChem Inc. Maximum Uncontrolled	Total Maximum Uncontrolled	Title V Threshold	
Particulate Matter 10 (PM10)	1.39	15.65	17.04	100	
Volatile Organic Compounds (VOC)	32.74	0.01	32.75	100	
Nitrogen Oxides (NOx)	0.21	0.21	0.42	100	
Carbon Monoxide (CO)	0.18	0.18	0.36	100	
Sulfur Dioxide (SO2)	0.04	0.04	0.08	100	
Total Hazardous Air Pollutants (HAP)	0.6052	14.32	14.925	25	
Hydrogen Chloride (HCl)2	0.2576	14.32	14.5776	10	
1.	All emissions are expressed in tons per year (tpy)
2.	Hydrogen Chloride is the largest individual HAP

As shown in the table above, GX Technologies does not exceed the Title V threshold for any criteria pollutants and as such, qualifies as a True Minor Source. However, both GX Technologies’ and PowerChem’s emissions combined have the potential to exceed the Title V threshold for individual HAPs. Since GX Technologies’ HCl emissions are low (< 1 tpy) and the majority of the combined HCl emissions are attributed to PowerChem, putting an emission limit on PowerChem’s individual HAP emissions will ensure that both facilities stay under the Title V threshold of 10 tpy. 

NSPS APPLICABILITY

Subpart Kb - Standards of Performance for Storage Vessels for Petroleum Liquids for Which Construction, Reconstruction, or Modification Commenced After July 23, 1984
This subpart applies to owners and operators of storage vessels with a capacity greater than 75 cubic meters (m3) that are used to store Volatile Organic Liquids (VOL). All storage tanks located at this facility have significantly smaller volumes than the minimum capacity and as such, this facility is not subject to this subpart.  

PUBLIC PARTICIPATION

The 30-day public notice period began on July 23, 2021, with the publication of a notice in The Natchez Democrat and ends Monday, August 23.

RECOMMENDATION

The staff has preliminarily decided to recommend issuance of the permit to the Mississippi Environmental Quality Permit Board as shown in the draft permit.  However, the staff recommendation to the Board will be made only after a thorough consideration of all public comments.