Design Features and Performance Evaluation of Natural-Draft, Continuous Operation Gasifier Cookstove

Brian Gumino,Paul Wever,Jonathan Barnes,Nicholas A Pohlman

doi:10.3390/cleantechnol2030017

Abstract

Biomass cookstoves are used as a common source of heating and cooking in developing countries with most improved cookstove design focusing on developing efficiency in thermal conversion of fuels and safer operation than open flame fires. A top-lit-up-draft (TLUD) cookstove utilizes a gasification process similar to pyrolysis where the solid biomass fuels are heated within a oxygen-limited environment and the syngas are burned which reduces carbon content and particulate matter being introduced into the air. The new continuous-operation design is described to have features for: (1) safe addition of solid fuels during combustion of syngas, (2) removal of biochar at the primary air inlet to manage gasification location, and (3) temperature control of the cooksurface through adjustable exhaust paths. The designed cookstove is found to have a diameter to height ratio 0.42-0.47 in order to offer the cleanest burning of the biofuel. The cooking surface is experimentally studied and the thermal gradient is found for compressed wood pellets. Tracking of the coal-bed is studied as a function of time in order to better understand when additional fuel should be added to ensure constant cooking temperature and operation. Numerous exhaust paths explore the cookstove user’s ability to control the temperature contour of the cooksurface.

Highlights

Different cooking mechanisms are used all over the world and have substantially different mechanisms depending on the user’s preferences [1]
These three brick fires (TBF) and open flame fires offer little to no directional concentration of heat as cross winds and other environmental aspects can vary the location and temperature of the flame at any given time since it is open to the atmosphere
Temperature gradients show heat is concentrated around the combustion zone with a contour of radial decay that can be controlled by restricting the flow of gases through the cooktop chamber

Summary

Introduction

Different cooking mechanisms are used all over the world and have substantially different mechanisms depending on the user’s preferences [1]. The TBF is an adaptation of the open flame fires—the most basic structure to build around combustion proves to be most problematic to the users These TBFs and open flame fires offer little to no directional concentration of heat as cross winds and other environmental aspects can vary the location and temperature of the flame at any given time since it is open to the atmosphere. These cooking mechanisms yield high quantity of particulate matter, which get released into the environment and can be very harmful to the users [7]. Another method of cooking is a rocket stove, which is more efficient than the TBF and the open flame fires and has a much lower emission of volatiles [8]

Methods

Results

Conclusion