Study On Emission Characteristics Of Engine Bench And Vehicle Road With Solid Ammonia SCR System

Selective catalytic reduction(SCR)system is a very effective NOx reduction technology,most commercial vehicles currently used SCR system reductant urea solution,However,due to some physical and chemical properties of urea aqueous solution itself(67.5%of water),there are some defects in the use,there will be urea crystallization and other issues.Solid ammonia SCR(SSCR)technology is to heat ammoniated metal chloride,direct injection of ammonia,the decomposition of the initial low temperature,the product of a single,the same quality reductant,the quality of metal chloride carrying reductant is very good Urea SCR technology alternatives.In this paper,we studied strontium chloride adsorption and desorption characteristics,Using ESC/ETC cycle bench cycle test and PEMS vehicle road emission test,the effect of reducing NOx in SSCR system was studied.The environmental recovery technology of ammonia-strontium chloride was studied.The effect of dissolving,concentration deactivating strontium chloride We performed thermal analysis calculation.In this paper,strontium chloride and 2%to 10%graphite expansion agent were mixed to form a strontium chloride-expanded graphite composite material.Ammonia gas is adsorbed at a pressure of more than 4 bar,the ammonia content of the final product is 46%,which is more than 2.5 times that of urea solution.Through thermogravimetric analysis,the results show that octa ammonia strontium chloride can release most of the ammonia gas at 40??130?,while the strontium chloride composite with expanded graphite can release ammonia gas at-45??40 ?.In the charge of ammonia process,4 bar pressure,the reaction goes fast,Under higher pressure,it is estimated that ammonia can be filled within 1 h.In this paper,the ESC steady-state cycle test and ETC transient cycle test are earried out on the engine test bench.The NOx emission is 1.5 g/kWh,which is lower than 2.0 g/kWh as stipulated in the national regulations.Based on the proportions of urban,suburban and high-speed road conditions of PEMS(draft for reviewing),this paper presents the regulatory compliance test for N3 vehicles equipped with SSCR system.The test results meet the regulatory requirements and have the potential to meet the requirements of higher emissions legislation.We use the PEMS system on the same road is compared with the NOx treated by the original row and the SSCR system.In the urban area,the SSCR can reduce the emission of NOx by 61.3%of the whole vehicle,which is obviously better than the urea SCR system.In the high-speed operation,SSCR can make the vehicle reduce NOx emissions by 85.3%,the effect is remarkable.The relationship between various emission factors and different road conditions(speed,acceleration,driving force,power and speed transient)is analyzed.It is found that the emission laws of CO and THC are similar and more affected by speed and power.Because of the installation of SSCR system,NOx will be lowest at high speed cruise and PM will decrease at high power.At high temperatures,high altitudes and alpine regions,we also conducted vehicle road test studies on NOx emissions from SSCR systems.In the alpine condition,the pressure build-up process of the SSCR system was recorded when the residual amount of ammonia was different,and the NOx emission characteristics of the SSCR system were studied by using PEMS vehicle road test.Under high temperature and plateau conditions,the SSCR system The adaptability of the SSCR system is also studied.At the same time,the PEMS vehicle road test is also used to study the NOx emission characteristics of the SSCR system.The results showed that the maximum pressure for ammonia formation in SSCR was 27 min in cold conditions,which was lower than that of urea SCR for 40 min.The NOx emission of SSCR was 2.8 g/kWh at high temperature,1.5 g/kWh at high temperature and 2.2 g/kWh at high altitude.We use the physical properties of ammonia and strontium chloride,the proposed multi-use deactivated ammonia strontium chloride for recycling program,strontium chloride dissolved,concentrated,granulated recovery,and the process carried out Hot calculation.