Code of Maine Rules
06 - DEPARTMENT OF ENVIRONMENTAL PROTECTION
096 - DEPARTMENT OF ENVIRONMENTAL PROTECTION - GENERAL
Chapter 124 - TOTAL REDUCED SULFUR CONTROL FROM KRAFT PULP MILLS
Section 096-124-2 - Definitions

A. Alternative TRS control system. "Alternative TRS control system" means alternative technologies (such as an air stripper or scrubber) used to remove TRS compounds from wastewater, gas streams or condensates.

B. Black liquor solids. "Black liquor solids" means the dry weight of the solids, which enter the recovery furnace in the black liquor.

C. Brownstock washer system. "Brownstock washer system" means brownstock washers and associated equipment used to wash the pulp following the digester system and prior to the bleaching system or oxygen delignification system.

D. Digester system. "Digester system" means each continuous digester or each batch digester used for the chemical treatment of wood or non-wood fibers at a Kraft pulp mill. The digester system equipment includes associated flash tank(s), blow tank(s), blow heat recovery accumulator(s), relief gas condenser(s), and pre-hydrolysis units preceding the brownstock washer system.

E. Evaporator system. "Evaporator system" means all equipment associated with increasing the solids content and/or concentrating spent cooking liquor from the brownstock washer system including pre-evaporators, multi-effect evaporators, concentrators, and vacuum systems, as well as associated condensers, hotwells and any other equipment serving the same function as those previously listed.

F. High volume, low concentration or HVLC collection system. "High volume, low concentration or HVLC collection system" means a system which collects and conveys TRS gases to a control device from equipment that could include, but is not limited to, the brownstock washer systems, oxygen delignification systems, any tertiary digester flash tanks, and any miscellaneous sources requiring TRS to be controlled.

G. Kraft pulp mill. "Kraft pulp mill" means any stationary source which produces pulp from wood by cooking (digesting) wood chips in white liquor (a water solution of sodium hydroxide and sodium sulfide) at elevated temperature and pressure. Regeneration of the cooking chemicals through a recovery process is part of the Kraft pulp mill.

H. Lime kiln. "Lime kiln" means a unit used to calcine lime mud, a process which consists primarily of converting calcium carbonate into quicklime, which is calcium oxide.

I. Low volume, high concentration or LVHC collection system. "Low volume, high concentration or LVHC collection system" means a system which collects and conveys TRS gases to a control device from equipment that could include, but is not limited to, the digester system, turpentine recovery system, evaporator systems, and any miscellaneous sources requiring TRS to be controlled.

J. Miscellaneous sources. "Miscellaneous sources" means sources of TRS which are not controlled but emit TRS at levels greater than 0.75 pounds per hour on a continuous basis under normal operations. Continuous means occurring for more than a two (2)-hour period. Miscellaneous sources may include, but not be limited to, knotters, screens, deckers, oxygen delignification systems, liquor storage tanks and chip bins.

K. Recovery furnace. "Recovery furnace" means an enclosed combustion device where concentrated black liquor is burned to recover sodium and sulfur and to produce steam for energy recovery.

L. Smelt dissolving tank. "Smelt dissolving tank" means a vessel used for dissolving the smelt collected from the recovery furnace.

M. Steam stripper collection system. "Steam stripper collection system" means a system which collects TRS off-gas from a steam stripper (including associated stripper feed tanks, condensers, or heat exchangers) and conveys the TRS gases to a designated control device. The steam stripper collection system also includes all equipment associated with a methanol rectification process including rectifiers, condensers, decanters, and storage tanks.

N. Total reduced sulfur (TRS). "Total reduced sulfur (TRS)" means the sum of the sulfur compounds hydrogen sulfide, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide, that are released during the Kraft pulping operation and measured by EPA Reference Method 16, 16A, or 16B in Appendix A of 40 CFR Part 60.

O. Twelve (12)-hour block average. "Twelve (12)-hour block average" means the discrete average of a twelve (12)-hour period from midnight to noon, and from noon to midnight or any other discrete twelve (12)-hour block average period approved by the Department for a particular source as specified in the source's air emission license.

P. Venting of TRS. "Venting of TRS" means the direct release of gases which contain TRS to the atmosphere in excess of 0.75 pounds per hour or five (5) ppm from any LVHC, HVLC, steam stripper collection system, or alternative TRS control system or associated equipment when such sources are in operation. Venting of TRS shall not include equipment leaks such as leaks around flanges, valves, and covers of quantities less than 0.1 lbs/hr.

Q. Waste water treatment system. "Waste water treatment system" means the system that treats process wastewater from the facility, which includes primary clarifiers, secondary clarifiers, polishing ponds, aeration lagoons and sludge press areas of the mill.

R. Wet-bottom electrostatic precipitator (wet-bottom ESP). "Wet-bottom electrostatic precipitator (wet-bottom ESP)" means an electrostatic precipitator where the particulate matter is removed from the bottom of the device with the use of black liquor.