Research On High Efficient Bio-energy Recovery And Utilization From Organic Solid Waste By Combined Microorgnism Aerobic-anaerobic Degradation

Based on the status of energy and MSW (Municipal Solid Waste) and rural straw processing in China, the biomass energy potential of MSW and rural straw was analyzed, and the concept of recycling system of high efficient bio-energy recovery and utilization from organic solid waste by combined microorgnism aerobic-anaerobic degradation was presented. Some related experiment platforms were desighed and set up and some experiments were performed with corn stalk to study the heat production characteristics by microorganism aerobic degradation, the biogas production and energy production characteristics and its optimal technological parameters by microorganism anaerobic degradation, and the energy production characteristics of combined microorgnism aerobic-anaerobic degradation. Also, the feasibility of biomass energy recovery for building heating and domestic hot water supply and the efficiency of BHP (Biogas Heat Pump) and its waste heat recovery was analyzed. The research results showed that:(1) For the study of aerobic degradation of corn stalk, the peak outlet air temperature was up to57.9℃while the average inlet air temperature was31.6℃; the average heat production rate was3.0W/kg (wet) and the energy production rate per unit volumn of the reactor was501.6W/m, and the recoverable energy was342.7MJ (about95.2kWh) in the7-day operation; during high-temperature stage (≥50℃), the average heat production rate was3.7W/kg (wet) and the recoverable energy was270.7MJ (about75.2kWh), which accounted for79.0%of total heat production; for a typical four people family, to meet the need of the daily domestic hot water supply and building heating during120-day heating period,37kg/d of organic solid waste (corn stalk etc.) was needed, which could produce18.65kWh/d of recoverable energy.(2) The optimal technological parameters of the biogas production from corn stalk by microorganism anaerobic degradation was:TS (Total Solid) content was22.5%, temperature was55±1℃, pressure of biogas-collecting was atmospheric pressure or below atmospheric pressure and adding appropriate amount of microelement, and under this conditions, the peak value of biogas production rate was2.59m3/(m3·d), the15-day average biogas production rate was1.05m/(m3·d), and the average methane concentration was59.5%. The average heat production rate per unit volumn of the reactor in the15-day operation was259.6W/m3.(3) The synthetical energy production rate from corn stalk by combined microorgnism aerobic-anaerobic degradation was646.7W/m, which was211.4%higher than that only by anaerobic degradation.(4) By contrast, the PER (Primary Energy Ratio) of BHP with waste heat recovery was respectively36.7%,40.6%,84.5%and116.5%higher than BHP without waste heat recovery, electric heat pump, coal-fired boiler, and gas-fired boiler. With biogas as the primary energy, the heat supply of BHP was1.624times of the total heat value of its biogas consumption. With utilizing the bio-energy recovery from corn stalk by microorgnism anaerobic degradation to drive the BHP, the synthetical energy production rate was421.6W/m3, which meant that to supply1kW energy just needed a reacter with2.37m3of net volume. With utilizing the bio-energy recovery from corn stalk by combined microorgnism aerobic-anaerobic degradation to drive the BHP, the synthetical energy production rate was737.2W/m3.