MEMORANDUM 

DATE: 	May 1, 2023

FROM: 	Patrick Miller (USEPA Region V) and Donna Lee Jones (USEPA OAQPS), U.S. Environmental Protection Agency

TO: 		Coke Ovens Residual Risk and Technology Review (RTR) Project File
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SUBJECT:	Soaking Emissions from Coke Ovens: Mountain State Carbon LLC, Follansbee, WV, Inspection June 15-16, 2021
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INTRODUCTION

      The purpose of this memorandum is to describe information about coke oven soaking emissions obtained during a recent inspection by U.S. Environmental Protection Agency staff in Region V of a coke battery at the Mountain State Carbon LLC coke manufacturing facility in Follansbee, WV (hereafter referred to as "Mountain State"). A technical description of emissions from soaking at coke by-product ovens in general also is included here.
      
BACKGROUND

      Soaking emissions are uncaptured coke oven gas regularly vented to the atmosphere as part of normal operations associated with pushing and can be a source of high opacity. The National Emissions Standards for Hazardous Air Pollutants (NESHAP) at 40 C.F.R. part 63, subpart CCCCC, for Coke Ovens: Pushing, Quenching, and Battery Stacks, hereafter referred to as Coke 5C NESHAP, defines soaking as that period in the coking cycle that starts when an oven is dampered-off from the collecting main and is vented to the atmosphere through an open standpipe prior to pushing coke from the oven and ends when the coke begins to be pushed from the oven, during which time the standpipe remains open and until the oven is charged. The standpipe is then closed when the oven is connected to the collecting main duct during charging and coking. Soaking emissions are the discharge of visible emissions from an open standpipe during the period when the oven is being readied to be pushed and is due to either incomplete coking in the coking cycle or leakage into the open standpipe from the collecting main, which collects the coke oven gas from every oven. 
      
SOAKING AT MOUNTAIN STATE CARBON, FOLLANSBEE, WV
 
      Representatives from Mountain State explained their operations prior to pushing an oven. First, the facility dampers the oven to be pushed from the collecting main prior to opening the standpipe cap to isolate the oven from the collecting main. The common practice at this facility is to damper off and open the standpipe caps for the next three ovens to be pushed at the same time as opposed to dampering off only the next oven to be pushed before opening the standpipe of the oven  being pushed, or to not damper off any other oven. This practice at Mountain State results in significant emissions of raw coke oven gas from the standpipe cap of the oven to be pushed that are not evaluated by topside workers. 
      
      The emissions from the standpipe cap from the ovens to be pushed during soaking at Mountain State would last anywhere from a few seconds to a few minutes. The amount of time between the opening of the standpipe of the oven to be pushed and pushing of the oven is an undetermined amount of time if other issues or delays require topside workers' attention to veer away from the ovens to be pushed. Topside workers are not in a position to evaluate soaking emissions when multiple ovens are dampered off from the collecting main and the standpipe cap is opened. By the time facility personnel arrive at an individual oven that is soaking prior to pushing or before the next ovens are pushed, the standpipe caps could have vented raw coke oven gas with actions required by the current rule for the Coke Ovens: Pushing Quenching, and Battery Stack NESHAP at § 63.7294. 

      During the U.S. EPA inspection by EPA Region V personnel on the above date at Mountain State, visible emission observations were conducted during pushing. The contractor who conducts visible emission observations for the facility informed the EPA staff that soaking emissions were considered interference and not read as part of the visible emission observation of ovens being pushed, at the facility. 

      The Coke 5C NESHAP (at § 63.7294) requires a facility to determine the cause of soaking emissions that do not ignite automatically, including emissions that result from raw coke oven gas leaking from the collecting main through the damper  and emissions from an oven that result from incomplete coking in the previous coking cycle. The soaking emissions witnessed onsite by EPA staff at Mountain State did not ignite automatically nor were facility personnel present to manually ignite the soaking emissions. There is no opacity limit for soaking emissions currently in the Coke 5C NESHAP. The head space volume of coke ovens at Mountain State is approximately 80 cubic feet (12 inches of head space above coke x 607 inches long x 19 inches wide). The pushing schedule during the EPA inspection indicated that 60 ovens would be pushed over a 24-hour period resulting in approximately 4,800 cubic feet of coke oven gas vented to the atmosphere (1,752,000 cubic feet annually). 
      
CONCLUSIONS

      The venting of soaking emissions occurs regularly enough at coke oven facilities that a secondary collecting main could be used to route emissions to a separate air pollution control device. Amendments to the Coke 5C NESHAP could require a separate air pollution control device with an associated limit and/or include an opacity limit for soaking emissions, which could be averaged over an appropriate period of time to reflect the nature of the operations and which would be required to occur as soon as the oven standpipe cap is opened. Work practice standards also could be added to the rule to include a corrective action requirement triggered by failure to meet the opacity limit and which could be required to be done after opacity greater than the limit is measured. This work practice would replace the current subjective determinations made by facility personnel during the course of typical coke oven operations. 
