3d model with pre-hydrolysis vessel

ANDRITZ technologies for dissolving pulp production

Processes and technologies available from ANDRITZ​​​​​​​

  • Wood processing
  • Pre-hydrolysis cooking
  • Drying dissolving pulps
  • White liquor plant
  • Evaporation plant
  • Recovery boilers

3d model of a fiberline with A-ConFlex™ technology retrofitted to an existing installation.

Pulp drying line for dissolving pulp

Wood processing: For all climates, species, and industries

ANDRITZ engineers advanced wood, chip, and biomass processing plants, as well as individual wood processing equipment for forest products and power industries. ANDRITZ is a leading supplier of systems, equipment, and processes for all steps required in a woodyard: from the arrival of logs at the plant to their subsequent preparation into wood chips. These chips are used in the production of chemical and mechanical pulps. Alternatively, the technology is used for the processing of biomass to generate energy.

ANDRITZ wood processing technologies are integrated and customized for all types of wood processing applications. Whether for processing whole trees, short wood, wood chips, or woody biomass, ANDRITZ has the right equipment for receiving, debarking, chipping, screening, storing, and reclaiming, as well as for handling waste streams.

Modern wood processing plants are designed for producing high-quality chips or biomass according to end product requirements. At the same time, the objective is to minimize labor and energy costs, wood losses, environmental load, and maintenance requirements.

Products include woodyard portal cranes, PowerFeed conveyors, debarking drums, RotaBarker debarkers, chippers, chip screens, screw reclaimers, bark shredders, bark presses, biomass crushers, pre-steaming bins, and grinder chargers.

ANDRITZ pre-hydrolysis cooking for dissolving pulp production

The key to dissolving pulp production is efficient removal and recovery of hemi-cellulose from the fiber source. The pre-hydrolysis vessel (PHV) from ANDRITZ is a new technology developed for cost-effective production of high-quality pulp and valuable by-products.

ANDRITZ has re-designed the cooking process to include auto-hydrolysis for efficient hemi-cellulose removal. The process design and technology components are based on experience in paper grade pulping, and they eliminate instabilities in previous systems. The design can be applied easily to existing installations.

This new ANDRITZ technology has gained rapid acceptance and is being delivered to several customers in Asia, where viscose fiber growth is the highest.

Installation and operational costs are likely to be much lower than traditional dissolving experience. Fiber yields are expected to be several percentage points higher than existing batch technologies due to better selectivity of the principle reactions and controlled, sustainable recovery of the by-products.

The current practice is to neutralize and burn the hydrolysate with the bulk black liquor. However, future developments will enable processing of this valuable stream for energy production, thus further improving the economics of the overall pulping process.

Processes and technologies available from ANDRITZ

  • Diamondback chip pre-steaming
  • TurboFeed chip feeding
  • Pre-hydrolysis treatment
  • Lo-Solids cooking
  • Clean steam technology
  • Hydrolysate treatment
  • Laboratory simulations and investigations

Drying dissolving pulps

ANDRITZ is well equipped to supply turnkey market dissolving pulp drying plants. A market dissolving pulp sheet drying plant usually starts at the high-density storage tower directly after the bleaching plant of the fiberline and includes pulp screening/cleaning, dewatering, drying, cutting and bale finishing, and/or roll finishing. ANDRITZ is well equipped to supply leading technologies for turnkey market dissolving pulp drying plants. The main difference between the qualities of kraft pulp and dissolving pulp is the content of alpha-cellulose, ash content, DCM-extractives, and the density of the pulp sheet.

  • Pulp screening/cleaning
  • Pulp dewatering
  • Pulp sheet drying
  • Pulp baling – bale finishing
  • Pulp roll finishing
  • Automation
  • Upgrades, rebuilds, and services

White liquor plant

ANDRITZ PULP & PAPER continues to develop technologies that minimize environmental impact by recycling and reusing process streams inside a mill rather than relying on end-of-pipe removal. This is particularly true in the white liquor plant, where the conversion of green liquor into high-quality cooking liquors is performed with great efficiency.

ANDRITZ has been an innovator in recausticizing, lime reburning, and auxiliary processes, and offers a strong portfolio of LimeLine components for each process stage and support operation. The scope includes process solutions for chemical conversion and filtration, equipment for the various steps of preparing cooking liquors, and on-going services. The product portfolio ranges from traditional white liquor production to other modified delignification liquors for kraft pulping. ANDRITZ draws from project experience in numerous new recausticizing plants, plant modernizations, new lime reburning kilns, kiln modernizations, and several plants for white liquor oxidation or modified white liquors worldwide.

LimeLine components are designed as stand-alone unit processes and offer truly superior performance when integrated into a modern, energy-efficient, and environmentally safe production line. The results are reduced and cleaner air emissions, better energy efficiency, reduced loads to landfill, and high white liquor quality – even with closed-cycle process loops.

Processes and technologies available from ANDRITZ

  • Recausticizing
  • Lime reburning
  • White liquor

Evaporation plants: Technologies and services for highly challenging pulp mill evaporation needs

For kraft and mechanical pulping, ANDRITZ offers complete systems for treating liquid streams and processing the condensates for optimum re-use, while minimizing energy consumption.

Processes and technologies available from ANDRITZ

  • Concentrators
  • Mechanical Vapor Recompression (MVR) evaporators
  • Multiple-effect evaporators
  • Pre-evaporators
  • ZEDIVAP effluent evaporators ZED/VAP

Chemical recovery boilers

ANDRITZ provides chemical regeneration processes for all pulping technologies.

ANDRITZ chemical recovery boilers offer designs capable of maximizing the production of green energy, with minimum emissions, while also recovering chemicals efficiently for the fiberline. ANDRITZ supplies complete chemical recovery boiler plants, typically on an EPC basis (Engineering, Procurement, and Construction of the entire system, including support structures, boiler house, and automation). Alternatively, the recovery boiler plant can be delivered as an EP project, in which case erection and installation work are performed by others. If requested, ANDRITZ is also able to deliver the “bare boiler” only, i.e. all pressure parts of the boiler. In that case, other equipment and sub-systems can be engineered in co-operation with the customer.

Chemical recovery boilers available from ANDRITZ

  • High-energy kraft recovery boilers (HERB)
  • Boilers for CTMP and APMP effluents (SodEx))
  • Sulfite boilers (SulfitePower)
  • Sodium boilers (SodEx)
  • Major upgrades and modernization components