Presentation of a dry black liquor gasification process with direct causticization

• In a new black liquor gasification process, black liquor is injected into a circulating fluidized bed, with sodium titanate (Na 2O· (TiO 2) 3) as the fluidizing medium.The organics are gasified mainly by steam reforming because the temperature is relatively low (below 870°C) and the water content of the black liquor is relatively high (>20% water).The black liquor inorganics consist mainly of sodium carbonate and sodium sulfate. In the reactor, sodium carbonate is converted into Na 2O·TiO 2, which is removed from the bed and dissolved in water to give 4 NaOH + Na 2O·(TiO 2)3. After dewatering, this material is reinjected into the fluidized bed.The sulfate is reduced to Na 2S, and most of the sulfur is evaporated as H 2S after Na 2S reacts with CO 2 + H 2O. In a scrubber, the H 2S is selectively absorbed without CO 2. The direct causticization makes the lime kiln unnecessary. The gas is reheated after dust is removed and then combusted in a gas turbine/steam turbine cycle, to produce 2-3 times more electricity than produced in steam cycles with conventional recovery boilers.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Pappers-, massa- och fiberteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Paper, Pulp and Fiber Technology (hsv//eng)

Nyckelord

gasification

black liquor

new process

Cellulose and paper engineering

Cellulosa- och pappersteknik

Publikations- och innehållstyp

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art (ämneskategori)