1. A Household Clean Biomass Cookstove Based on Pyrolysis and Successive Combustion
of Pyrolysis Products (Gases and Biochar)
Li, Hanhui
Brown University, Providence, RI, USA
Abstract
This project aims at developing a miniaturized and household clean biomass pyrolysis
cookstove based on thermochemical conversion technology. Traditional cookstoves with
direct combustion of biomass have already been used for thousands of years. Harmful effects
of dense smoke produced by these stoves are far more severe than what people imagine.
Moreover, the harmful smoke directly affects over one third of the world population.
I conceived a technical program: biomass could be turned into gas and biochar through
pyrolysis reactor, and then these two products (gas and biochar) of biomass pyrolysis reaction
could be burned successively to provide energy for cooking.
I developed a cookstove prototype by using rotary drum-type pyrolysis reactor which
consisted of a hollow cylindrical stator and a rotator inside the stator. The stator could
generate a thermal field, and then the rotator was able to absorb thermal energy from the field
and transfer it to biomass inside the rotator. Results of the test on the prototype showed that
this cookstove could output 12.75 MJ heat energy for cooking after consuming 0.6KWh
electricity and 1Kg biomass. Smoke pollutants included CO, NOx and smoke dust,
concentrations of which were 0.085%, 126mg/m3
and 21mg/m3
respectively.
This project has double contributions First, the reactor is a unique design. It enables
biomass to contact the inner wall of the reactor evenly in the pyrolysis process. Ignition is no
longer needed. Second, the thermal conversion efficiency of this stove is found to be greater
than that reported in the literature cited (83.6% vs. 65%). The stove emits very little smoke
dust (21mg/m3
vs. 50mg/m3
).
Key words: Reactor, Cookstove, Pyrolysis, Biomass, Energy, Pollution