NCG Systems

From studies to EPC installation, LDX Solutions is the leading supplier of non-condensable gas (NCG) ventilation systems in the pulp and paper industry with decades of experience. This includes extensive experience with collecting all types of NCG sources, including High Volume Low Concentration (HVLC), Low Volume High Concentration (LVHC), and Stripper Off Gas (SOG.).  

NCG Collection Station

NCG Collection Station


LDX Solutions designs Non-Condensable Gas handling systems for Dilute, Concentrated, and Stripper Off Gas systems. These systems are designed for the safest possible operation and to meet the most stringent environmental regulations.

  • Our systems are designed to collect, transport and treat the waste gases safely and efficiently.
  • Thermal oxidation of the waste gases can be achieved in the recovery boiler, power boiler, lime kiln or a dedicated incinerator.
  • Scrubbing of acid gases after oxidation can also be provided.
  • Systems can be designed with automatic ventless transfer between various incineration points.
  • Our systems are designed to minimize the intrusion of excess air into the vent system.
  • System interlocks are designed to protect both personnel and system integrity.
  • Piping and drainage systems are designed to eliminate the potential for condensate build up in the piping and other equipment.
NCG Incinerator With Heat Recovery

NCG Incinerator With Heat Recovery

Black Liquor Oxidation

Single Stage BLOX Reactor System

Single Stage BLOX Reactor System

LDX Solutions pioneered the science of black liquor oxidation in the pulp and paper industry more than 50 years ago. The purpose of black liquor oxidation is to remove residual Na2S in black liquor by oxidizing it to the stable sodium thiosulfate prior to a direct contact evaporator. We have developed two separate approaches to system design. Where space is not an issue, oxidation occurs in two equal sized tanks in series. Where space is constrained, the use of concentric tanks allows for a two-stage operation with a smaller footprint. Systems are generally designed for higher liquor solids to avoid foaming issues.


  • Oxidation systems may be installed on either the weak liquor or on the strong liquor, though strong liquor is preferred.
  • LDX Solutions utilizes a proprietary Lundberg sparger to maximize contact between the air and the black liquor to improve efficiency and minimize energy consumption for this critical environmental control system.
  • In addition to the reactor design, we can supply a BLOX finisher for systems that need better results without a complete rebuild.
BLOX Reactors

BLOX Reactors


BLOX Finisher

Condensate Stripping

LDX Solutions is the leader in the technology of steam stripping foul process condensates from chemical pulping.

Steam stripping of foul process condensates is recognized as an efficient method for the removal of methanol, Total Reduced Sulfur (TRS) compounds and other Hazardous Air Pollutants (HAPs). LDX Solutions has standalone Lundberg designs and systems that can be integrated into your existing evaporator train or other mill process to optimize energy efficiency. Our stripping systems can supply clean condensates for reuse in your process.  Rectification and liquefaction systems can also be designed.


Integrated Stripping System


  • Lundberg systems are custom designed to fit your process and minimize steam usage.
  • Our stripping systems can be standalone units or integrated into the black liquor evaporator system.
  • Lundberg systems maximize the energy that may be recovered by heating boiler feed water, heating process water, heating black liquor, evaporation of black liquor or by generation of clean steam at a reduced pressure.
  • We can also design systems to include the option for additional rectification or liquefaction of the methanol to increase the fuel value and eliminate SOG handling.

Stripping and Methanol Liquefaction


Let LDX Solutions Be Your Environmental Industry Solution

For A Cleaner World

Further making us the best solution for your Energy Saving needs is our unparalleled service and life-cycle support. See how our Aftermarket team can keep you online and make you more profitable, regardless of the equipment you currently use today.