The Research Of Rural Cookstove Remodeling For Improving Its Thermal Performance And Pollutant Emission

China’s rural population accounts for 49.7%of the country’s total population,and firewood accounts for 44.2%of rural households’energy consumption.At present,most of the rural areas still retain cookstoves for cooking or boiling hot water,but the traditional cookstoves have problems such as poor thermal performance,serious emissions of pollutants.In this paper,a type of embedded stove core is developed,which can be embedded into conventional cookstove to realize the remodeling of the cookstove.The influence of the type of raw materials,secondary air and size of cast-iron pot on thermal performance and pollutant emission of the remodeled laboratory stove was studied.The demonstration of rural cookstove remodeling was carried out in Shourong village,Anji county,Huzhou city,Zhejiang province.Twenty-two rural cookstoves were remodeled on the spot,and eight of them were tested for their thermal performance and pollutant emission before and after remodeling.The main research contents and results were as follow.（1）Development of embedded stove core which could be used in cookstove remodeling.In the design principle of convenient operation,low cost and good compatibility,a type of embedded stove core was developed,which had the structural characteristics of primary and secondary air distribution,air space insulation and fuel staged combustion.The development of embedded stove core provided a guarantee for construction of experimental cookstove and The demonstration of rural cookstove remodeling.（2）Experimental research of performance of core-embedded cookstove in laboratory.The kind of raw material had little effect on thermal efficiency of the stove.In terms of thermal intensity in heating stage,thermal intensity in evaporation stage and cooking power,pine>hardwood>briquette fuel>bamboo;SO₂ emission concentration combusted from four materials was lower than 3.0 mg/m³.In terms of CO emission concentration,hardwood>pine>bamboo>briquette fuel;In terms of NO,NO₂ and NO_x emission concentration,hardwood>bamboo>briquette fuel>pine;In terms of particle matter emission concentration,pine>hardwood>bamboo>briquette fuel;Fuel stacking combustion was more stable than fuel staging combustion.NO_x cocentration combusted from four materials was stable.When compared with condition without secondary air,thermal performance（including thermal efficiency,thermal intensity in heating stage,thermal intensity in evaporation stage and cooking power）was improved and emission of pollutants（including CO,NO₂,NO_x and particulate matter）was reduced from four materials under condition with secondary air,which confirmed rationality of structural parameters of secondary air.（3）The demonstration of rural cookstove remodeling and test of their performance.Remodeling time of every rural cookstove was about two hours.Regardless of the influence of coil pot,thermal intensity in heating stage,thermal intensity in evaporation stage,cooking power and thermal efficiency was improved by 50.4%,25.7%,43.6%and 24.9%respectively on average after cookstove remodeling.When the influence of coil pot was considered,thermal intensity in heating stage,thermal intensity in evaporation stage,cooking power and thermal efficiency was improved by 53.4%,34.1%,50.1%and 29.8%respectively on average after cookstove remodeling.SO₂ emission concentration of rural cookstove before and after remodeling was lower than 3.0 mg/m³.The emission concentration of CO,NO₂,and particulate matter was reduced by 75.3%,77.1%,and 88.5%respectively on average after cookstove remodeling.Results of investigation showed that most of farmers were satisfied with effect of cookstove remodeling.The demonstration of cookstove remodeling in Anji county,China was received attention and recognition from CEO of Global Alliance for Clean Cookstoves,Vice President of social performance of Shell Group and leaders of relevant Chinese government departments.