An experimental study of spontaneous ignition in storages of wood pellets

• This article focuses on experimental studies of self-heating characteristics of wood pellets. Controlled experiments have been conducted in physical scales from 1 dm3 to 4 m3 with wood pellets. Basket tests have been conducted according to the "crossing-point method" to derive kinetic data on the exothermic reactions responsible for self-heating and eventually spontaneous ignition. The kinetic data was used in the planning of the large-scale experiments for predictions of approximate critical temperatures. The experiments in the 1 m3 scale were set-up basically as an enlargement of the basket tests to obtain validation experiments with controlled boundary conditions in a reasonable large scale. Several experiments were conducted and spontaneous ignition was seen in the centre of the pellet bulk at an ambient temperature of 115C. The close to real-scale experiments with 4 m3 wood pellets filled in a 6 m high silo were not strictly self heating experiments, instead a core shaped heating element was allowed to initiate the pyrolysis in the pellets. Heat and gas production and transportation from the growing pyrolysis zone were mapped with a large number of measurement points in the pellets bulk and in the top of the silo. The experimental work conducted gave kinetic data on the exothermic reactions in wood pellets, insight in self heating processes, a link between different experimental scales and knowledge regarding possibilities for detection of fires in storages of wood pellets.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Samhällsbyggnadsteknik -- Husbyggnad (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Civil Engineering -- Building Technologies (hsv//eng)

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

Keyword

Pelletizing

Biofuels

Exothermic reactions

Experiments

Heating

Kinetics

Silos (agricultural)

Spontaneous combustion

Temperature

Wood

Publication and Content Type

kon (subject category)

vet (subject category)