Gasification of black liquor is a key technology that can provide strategic benefits for both pulp and paper mills and the society in general. The following important conclusions can be drawn from the final report of the MISTRA-programme "Ecocyclic Pulp Mill":

1. An integrated paper mill can be self-supported of both heat and electricity.
2. Black liquor gasification can be used in alternative sulphur-free processes yielding a lower environmental load and lower investment costs.
3. Black liquor gasification gives an increased production of electrical power that can replace electricity generated from fossil fuels. Reduction of fossil carbon dioxide amounts to 240-500 kg/ tonne pulp (depending on if the alternative is natural gas or coal).
4. In general, black liquor gasification has the potential to produce internal mill-chemicals in addition to electricity generation.
5. Black liquor gasification may also result in lower maintenance costs.

Another benefit with pressurised black liquor gasification is that, with relatively small changes in pressure and temperature, the amount of sulphur and sodium in the liquid phase and gas phase, respectively, can be controlled. Hereby, new control possibilities for the process chemistry in a paper mill is possible. One benefit from this is that the yield from the wood can be increased by up to 5%.

From a national strategic energy point of view, a large-scale utilisation of black liquor gasification in Swedish pulp industry would yield a significant addition of electrical power (order of 1000 MW) to the national electricity network. This additional electricity will be available all year round, except at scheduled breaks for maintenance (typically one week per year for each plant), and also satisfies the demands for long-term sustainability in future energy systems due to the use of biomass.

Many different alternatives for gasification of black liquor have been proposed but the process that has reached the furthest is the so-called Chemrec-process. This process is based on pressurised gasification in an entrained flow downflow reactor followed by a quench cooling of the smelt to minimise the absorption of CO2 in the smelt. The Chemrec-process is the technology that will be implemented in the development plant that is constructed at ETC, Piteå, during winter 2001/2002 by aid of STEM (FABEL programme), Kappa Kraftliner (supplier of black liquor and receiver of green liquor plus some work of their own), and Piteå municipality (construction of laboratory hall). The development plant will be owned by Chemrec AB but located in the laboratory of ETC. The black liquor for the plant will be taken from the Kappa Kraftliner mill situated right next to ETC. This new, world-unique development plant will provide data for the design of a full-scale plant and bring Swedish research in black liquor gasification to a front position in the world.

In order to give an understanding of the potential market for this technology it should be noted that there are about 600 recovery boilers in the world today. Most of the boilers are built in the 60's and 70's and many of these are today in great need of re-investments. If all recovery boilers in the world would be replaced by pressurised black liquor gasification this would correspond to a total investment of the order of 60 billion Euro since the cost of a typical gasifier unit is of the order of 100 million Euro. These investments will off course be made over a longer period but still the annual market potential is several billion Euro.

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