Study On Dynamics Performance Of Biomass Based Ethyl Levulinate Blended Fuels

Bioenergy is a kind of renewable energy which can be collected, stored, transported and isthe most similar to conventional fossil fuel. It is not only green clean energy, but also the onlykind of carbon resources of renewable energy that can be cultivated and converted into liquidfuels, and it thus plays an important role in the six kinds of renewable energy sources.Lignocellulosic biomass is the most abundant and cheapest biomass resources on the earth. Inchina, there is more than700million tons lignocellulosic biomass can be used as energy, suchas agricultural and forestry residues. Lignocellulosic biomass can be converted into liquid fuelsand then used as internal combustion engine alternative fuels, which is an importantdevelopment direction and has a practical significance for enhancing the oil security, alleviatingthe pressure of energy and resources, reducing environmental pollution, and developing thesocial economy. Ethyl leculinate （EL） can be gotten from lignocellulosic biomass, and EL hasbeen studied as a vehicle fuel abroad. But its power and emissions performance of diesel engineresearch has not been done domestic. Therefore, on the base of biomass resources in China, it isvery important to take corn stalk based EL as study object by analyzing performance of dieselengine with blended fuels of EL and diesel, so as to find the appropriate proportion of EL-dieselblended fuels. All of that is conducive to the promotion of biomass based EL, along withrational and large-scale utilization of biomass resource in China.In the paper, process and reaction conditions of transforming biomass such as corn stalk tolevulinic acid and EL were study. Dynamic performance of EL-diesel blended fuels wasanalyzed. The combustion, economy and emission characteristics of EL-diesel blended fuelswere investigated using engine bench tests. The range of EL-diesel blended fuels to suit fordiesel and diesel engine system of China was found. For taking EL as the key fuel, physical andchemical properties of different fuel formulas were studied according to EL, biodiesel and dieselproperties. The fuel formulas were optimized and selected in line with China National Standardsand Codes, and dynamic performance of the fuel formulas were verified on a diesel engine. Lifecycle energy consumption, environmental emission and economy of corn stalk based EL were analyzed, and several improvement to related units were given. The results shown that:（1）Corn stalk has a large advantage in producing potentially interesting derivatives oflevulinic acid by hydrolysis according to high content of cellulose and hemicellulose, lowcontent ash. Residue of corn stalk after producing furfural can be used to make levulinic acid,levulinic acid yield can be reached70%at the optimum condition of reaction temperature,concentration of sulfuric acid, ratio of liquid to solid, reaction time. Resin of polarizedadsorption has the better separation effect on levulinic acid, the levulinic acid yield was82.2%at the suitable condition of levulinic acid concentration, flow rate, ratio of height to diameter ofpacked column, concentration of hydrochloric acid. Solid acid catalyst was selected inesterification, the better condition of Vlevulinic acid:Vethanol, reaction time, reaction temperature, andMcatalyst:Msulfuric acidwere found, respectively.（2）An appropriate proportion of EL-diesel blended fuels can be normally used in ahorizontal single cylinder four stroke diesel engine, without any modification to the engine.EL-diesel blended fuels and diesel have the same trend in the dynamic changes of the externalcharacteristics. Torque and power of EL-diesel blended fuels were slightly lower than diesel.Brake specific fuel consumptions （BSFC） of EL-diesel blended fuels were slightly higher thandiesel, but energy consumptions were lower. Emissions of NOxand CO₂were higher than dieselwhen the output power became larger. Emissions of CO and smoke opacity were reduced withincreasing percentage of EL when the output power became larger. BSFC was influenced mostby the density of the blended fuels. NOx, CO, and CO₂emissions were influenced most by theoxygen content. The KV was the most influential parameter for HC emissions and the opacity ofthe blended fuels. The oxygen content was the foremost influential parameter. The influence ofthe blended fuels parameters on smoke opacity was the greatest.（3）For taking EL as the key fuel, physical and chemical properties including solubility,cold flow properties, atomization and evaporation, oxidation stability, anti-corrosion properties,cleanness, ignition properties, heat value of different fuel formulas of EL-biodiesel-diesel werestudied.13kinds of fuel formulas were gotten and10of them were in line with China NationalStandards and Codes: GB/T25199-2010biodiesel fuel blend（B5）.The test of physical andchemical properties shown that the fuel formulas with EL and biodiesel have collaboration,mutual promotion. Physical and chemical properties of diesel with an appropriate proportion ofEL and biodiesel were similar to pure diesel and can be suit for diesel engine. Experimentalverification was taken in diesel engine with4selected fuel formulas, the results shown thatdynamic performance of the fuel formulas was almost the same as diesel, fuel economy wasbetter than diesel, emission of HC, CO and smoke opacity was significantly lower than diesel.Energy saving and emission reduction were realized. （4）The model of life cycle energy consumption, environmental emission and economy ofcorn stalk based ethyl leculinate was built. The unit processes of corn stalk growth, collection,transportation, pretreatment, hydrolysis and esterification, EL fuel transportation, andcombustion in engine were investigated. The system boundary of life cycle was defined. Theinterrelated data was collected, arranged and assessment. In the life cycle of biomass based EL,the most energy consumption was in process of corn stalk hydrolysis and esterification,accounting for more than66%of total consumption. The similar energy consumption was incorn stalk collection and pretreatment, accounting for16.0%and15.5%of the total,respectively. It is the major energy-saving way and development direction to improve efficiencyof corn stalk hydrolysis and esterification. It is also important to reducing energy consumptionin corn stalk collection and pretreatment. Compared to conventional diesel, NOx, PM10, SO2andgreenhouse gas of biomass based EL was much lower. NPV increased with an increase in ELand furfural price; NPV decreased with an increase in corn stalk price, capital cost, ethanol costand labour cost. The influence of the EL price on the change in NPV was the most significant.