Analysis Of Energy Consumption For Assisted Treatment Of High-Salinity Wastewater By Solar Energy

Coal is the main energy product of my country.Inner Mongolia Autonomous Region is a major coal-producing province,and its proven coal reserves now rank first in the country.Therefore,the coal-based energy and chemical industry situation arises accordingly.The huge coal chemical industry has produced a large amount of high-salt wastewater.However,the treatment of high-salt wastewater has outstanding problems of high investment,high consumption and high energy consumption.Evaporative crystallization technology is currently a relatively mature technology for the treatment of high-salt concentrated wastewater.The evaporative concentration operation mainly uses a steady stream of raw steam as a heat source,and the energy consumption caused by the consumption of raw steam is quite large.Producing raw steam consumes large amounts of coal and emits large amounts of CO₂into the atmosphere.Combined with the abundant solar energy resources in Inner Mongolia Autonomous Region,the total annual solar radiation is between 4858 and 6925 MJ/m²,and the annual sunshine hours are between2600 and 3400 hours,which is one of the high-value areas in the country.Therefore,the application of solar energy to high-salt wastewater treatment for Inner Mongolia has broad prospects.In this thesis,two technologies of conventional treatment of high-salinity wastewater and solar-assisted treatment of high-salinity wastewater are simulated and energy consumption analyzed.Heat pipe heat to transfer model,CPC heat exchanger model,degassing tower model,three-effect evaporation model and CPC variable frequency circulating pump power model.The CPC solar collector system,three-effect evaporation device and electrodialysis device were coupled by simulation,and the effects of distillate feed ratio,reflux ratio,column pressure drop,and total number of columns on the degassing column load and degassing effect was analyzed.Analyze the performance of the whole system with different tracking methods,different number of serial plates and different process routes of the CPC collector.Finally,the energy consumption of solar-assisted treatment of high-salt wastewater and traditional treatment of high-salt wastewater is compared and economical analysis is carried out.（1）From 9-16 on the day of the summer solstice,only the east-west horizontal tracking mode cannot meet the steam conditions for the whole time period,and its effect is significantly worse than the other two single-axis tracking methods.The CPC output temperature in the north-south axis and the north-south horizontal tracking state All conditions is met.In the two modes,the north-south axis tracking variable frequency circulating pump consumes the lowest power.Therefore,the north-south axis tracking is the optimal tracking method of 9-16 on the summer solstice day.When the time span is adjusted to one year,the CO₂emissions of the north-south horizontal type and the east-west horizontal type are not much different.The annual CO₂emissions under the four uniaxial tracking methods are integrated tracking type<north-south axis type<east-west horizontal type<north-south horizontal.The four uniaxial tracking methods in the three-effect evaporation-electrodialysis route are the traditional methods.43.62%,44.04%,52.54%,58.31%of the traditional way.Therefore,with the whole year as the time span,integrated tracking is the best tracking method.（2）Among the three process routes,when the time is a certain day,such as the day of the summer solstice（n=141）,it can be seen from the figure that the numbers of these types of series plates all meet the conditions on the day of the summer solstice,and the number of series plates is 1 compared to 1.The power consumption of the CPC variable frequency circulating pump is the lowest compared to other series boards.When the time span is adjusted to one year,with the increase of the number of series plates,the temperature of the CPC heat exchange medium and the CPC output temperature increase as a whole.The time to satisfy the steam condition is very close for the number 3in series and the number 4 in series.In the multi-effect evaporation-multi-effect evaporation process route,the CO₂emission of plate number 3 is 82.75%of that of the traditional method,and the CO₂emission of plate number 4 is 82.71%of that of the traditional method.In the electrodialysis-three-effect evaporation process route,the cost of plate number 3 is 86.84%of that of the traditional method,and the CO₂emission of plate number 4 is 86.79%of that of the traditional method.In the CPC coupled three-effect evaporation process route,the cost of plate number 3 is 82.83%of that of the traditional method,and the CO₂emission of plate number 4 is 82.82%of that of the traditional method.The reduction rate of CO₂emissions is very close,considering the factors of operation and maintenance,the number of plates 3 is the optimal number of plates.（3）Under the best tracking method,the CO₂emission from the three-effect evaporation-electrodialysis process route during the simulation period is 97.5t,which is43.62%of the traditional method;under normal production conditions,the CO₂emission is522.82t,which is the traditional 83.62%of the way.In the electrodialysis-three-effect evaporation process route,the CO₂emission from the simulation period is 103.82t,which is 56.79%of the traditional method;under normal production conditions,the CO₂emission is 448.96t,which is 87.4%of the traditional method.In the CPC coupled three-effect evaporation process route,the CO₂emission from the simulation period is 98.98t,which is42.79%of the traditional method;under normal production conditions,the CO₂emission is541.55t,which is 83.32%of the traditional method.It can be seen that the CO₂emissions of the three process route are 83.62%,87.4%and 83.32%of the traditional methods,respectively.Although the energy-saving effect of CPC coupled triple-effect evaporation is more obvious,the overall CO₂emissions of the electrodialysis-triple-effect evaporation process The route is obviously better than the other two,so the process route of electrodialysis-three-effect evaporation is the optimal process route.