Pulp and Paper

Industrial gases such as oxygen, nitrogen, and carbon dioxide are used in a variety of operations throughout the pulp and paper production process, from delignification and chemical recovery to inerting, pH control and wastewater treatment. These gases offer a range of benefits, including reduced operating costs and emissions, minimization of chemicals consumption, odor control, productivity increase, and fuel savings. Air Products has the experience needed to implement these gases efficiently to provide the optimal combination of benefits and cost savings.

Oxygen Delignification

Oxygen delignification is a proven technology widely used to remove 40-50% of the residual lignin in non-bleached pulp. Use of oxygen reduces operating costs by reducing the amount of bleaching chemicals required in subsequent processing by targeting the easily oxidized lignin molecules. Oxygen also serves to reduce the emission of chlorinated byproducts and lowers the organic load and toxicity of the resulting wastewater. Additionally, it can be used in extended oxygen delignification (EOD) to increase the efficiency of the fiber lines.

Oxidative Alkaline Extraction

The introduction of oxygen to alkaline extraction is a proven method used for kraft bleaching. Oxygen, added during the alkaline extraction stage, serves to remove additional residual lignin, increases brightness and saves on bleaching chemicals, reducing environmental impact.

Ozone Production

Ozone is generated from electrical discharge on an oxygen gas stream. It is unstable at ambient temperatures and must be generated from oxygen on-site. The use of ozone provides efficient delignification with reduced consumption of bleaching chemicals and effluent load.

White Liquor Oxidation (WLO)

The white liquor oxidation process uses oxygen to oxidize sodium sulfide and sodium sulfate. Heat generated during this exothermic process can be recuperated. The process produces an economical alkali source used in bleaching and deliginfication processes and helps to reduce caustic purchases, while providing better control of the plant's chemical balance.

Black Liquor Oxidation (BLO)

The black liquor oxidation process uses oxygen to oxidize sodium sulfate to sodium thiosulfate, alleviating recovery boiler bottlenecks. BLO can help to reduce sulfur losses that occur during the multiple effect evaporation and reduce odor emissions in processes with direct contact evaporators.

Lime Kiln Enrichment

Oxygen enrichment of the lime kiln is a proven technique to achieve a number of benefits for captive lime production in a paper mill. These benefits include: production increases of up to 20%, fuel savings, reduced need for make up CaO, reduced sulfur compound emissions (TRS), and improved operational flexibility and kiln stability. Increased kiln thruputs allow more lime to be recovered and less waste sent to landfills. The economics of lime kiln enrichment can have very short paybacks.

Inerting and Blanketing

Nitrogen has several inerting and blanketing uses within pulp and paper mills, including tanks and piping, silos for plants with pneumatic ash handling, and chlorine rail cars.

Pulp Washing, pH Maintenance and Wastewater Treatment

Carbon dioxide (CO₂) can be used to increase production in pulp washing and to reduce corrosion in paper machines by replacing acids for pH control. In wastewater treatment, CO₂ is used for pH control and oxygen is used for odor control as well as secondary water treatment, where it significantly improves performance versus air-based treatment processes.

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Gases

Air Products gases, typically provided in gaseous and liquid form, enable customers in a wide range of industries to improve their environmental performance, product quality, and productivity.

Carbon Dioxide

Our experienced applications teams across the globe can use their industry and application knowledge to provide you with a compressed or liquid carbon dioxide supply and technology solution to meet your unique needs.

Nitrogen

Useful as a gas, for its inert properties, and as a liquid for cooling and freezing. Virtually any industry can benefit from its unique properties to improve yields, optimise performance and make operations safer.

Oxygen

In addition to its use as a respiratory gas for healthcare applications, its strong oxidising properties benefit many industries by improving yields, optimising performance, lowering costs and reducing carbon footprint compared to other fuels.

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Related Industries

Air Products offers thousands of products and services to a variety of different industries. This scope and experience has enabled us to develop a deeper understanding of the demands of these industries, and of your particular needs.

We have provided information most relevant to you within this industry section, but you may find information in other related industries of interest as well. The attached list is provided as a convenience for you or you can click on “Industries” in the top navigation for a full listing.