Study On Greenhouse Gas Emission Reduction Of Straw Briquette Fuel For Central Heating

Straw briquette is an important way of new type energy utilization for crop straw resources in China.Straw briquette based central heating project is of great significance to realize the recycling of agricultural waste straw resources,promote the development of comprehensive utilization of straw,save fossil energy and slow down the greenhouse effect.Based on literature research and field survey,the development status of straw briquette based central heating in China was systematically summarized.Fuel costs of biomass briquette,coal and some other fuels based central heating methods were quantitatively compared and analyzed.The quantitative estimation method system of greenhouse gas emission reduction of straw briquette based central heating project was established,which is based on the background of straw natural decomposition.A case study of straw briquette based central heating project in Lintao County of Gansu Province was carried out to comprehensively and quantitatively evaluate the emission reduction capacity of project.Finally,some policy suggestions on the promotion of straw briquette based central heating project were put forward based on this study.The main conclusions are as follows:（1）Considering the three main factors,e.g.,fuel calorific value,unit price and heating boiler thermal efficiency,which affect the fuel cost of central heating,fuel cost of several domestic central heating methods are quantitatively compared and analyzed.The results show that the cost of biomass briquette is slightly higher than that of coal,but both are far lower than that of natural gas and diesel.At the same time,the fuel cost of biomass briquette compared with coal is affected by the difficulty degree of resource acquisition and the advanced level of technology and equipment,which leads to regional difference between these two fuels based central heating.（2）According to the procedure of“resource substitution→greenhouse gas emission reduction”,the estimation method and parameter system of greenhouse gas emission reduction of straw briquette based central heating were put forward.The method system includes four parts:project boundary,baseline emission,project emission and leakage.The baseline emission is the sum of emission from natural decomposition of straw stacked in open air,emission from alternative fossil fuel coal heating,and emission of energy consumption for chemical fertilizer production replaced by ash from straw utilization.The project emission is the sum of fossil fuel consumption from engineering transportation activities,power consumption generated by straw molding,and utilization emission of straw briquette combustion for heating.The project leakage is zero.The total formula is:“net emission reduction of straw briquette based central heating project=baseline emission-energy consumption emission of straw utilization-project leakage.”（3）By using the above method system,a case study on the straw briquette based central heating project in Lintao county was carried out.The results show that:during the heating season from 2019 to2020,the baseline emission of straw briquette based central heating project in Lintao county is 2604.47 t CO₂,the project emission is 150.80 t CO₂,and the net emission reduction is 2453.68 t CO₂,which is equivalent to reducing the CO₂ emission of 862.95 t standard coal.The net emission reduction of straw briquette based central heating project is equivalent to 16.3 times of the project emission.For every 1 t corn straw consumed in the straw briquette based central heating project in Lintao County,the CO₂emission will be reduced by 1.56 t.（4）In order to further accelerate the promotion of biomass briquette central heating,it is urgent to build a complete straw collection,storage,transportation and marketing system,strengthen the research and development of relevant technical equipment,introduce relevant supporting policies,and improve the public awareness of energy conservation,environmental protection and clean heating.