外源吸收剂对沼液CO_2吸收及农业应用的影响  

Effect of exogenous absorbents addition on CO_2 absorption performance of biogas slurry and its agricultural application

作　　者：王文超[1] 贺清尧 余歌[1] 刘璐[1] 晏水平[1] 

机构地区：[1]华中农业大学工学院,湖北武汉430070

出　　处：《化工进展》2017年第4期1512-1520,共9页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金项目(51376078)

摘　　要：作为生物质厌氧发酵产沼气的副产物,沼液呈弱碱性,并富含刺激植物生长的有益成分,理论上可作为一种融合CO_2吸收和CO_2生物储存的可再生吸收剂,但沼液CO_2吸收性能需要强化。外源CO_2吸收剂的添加有助于提升沼液的CO_2吸收性能,但也会影响沼液的植物生理毒性。因此,本文在经典鼓泡式CO_2吸收装置中,研究了6种典型外源吸收剂对沼液CO_2吸收性能及植物生理毒性的影响,探究了沼液浓缩倍数和外源吸收剂添加量对沼液CO_2吸收性能的提升效果,并从植物生理毒性及总磷含量角度探讨了其对沼液农业应用的影响。结果表明:减压浓缩对沼液中主要有害物质氨氮具有脱除作用,当沼液被浓缩到5倍时,氨氮脱除率可达87.69%。与直接向原沼液中引入低浓度外源吸收剂相比,通过向浓缩沼液中添加高浓度吸收剂不仅可大幅提高单位体积沼液的CO_2携带量,而且将富CO_2沼液稀释至浓缩前的体积后,其种子发芽指数(GI值)也优于原沼液。同时,外源吸收剂的添加对沼液中总磷具有一定脱除作用,降低了沼液应用过程中磷对环境的潜在危害。6种外源吸收剂中,乙醇胺(MEA)在提高沼液CO_2吸收性能及降低植物生理毒性等方面具有综合优势。Biogas slurry is the byproduct of biogas produced by anaerobic fermentation of biomass, which is weak alkaline and rich in useful ingredients stimulating the plant growth. Theoretically, biogas slurry can be used as a renewable absorbent combining CO2 absorption and CO2 biological fixation. But COg absorption performance of biogas slurry needs to be enhanced. Adding exogenous CO2 absorbents into biogas slurry can contribute to promoting CO2 absorption performance of biogas slurry, but also affect its phytotoxicity. So, the effects of 6 exogenous CO2 absorbents added into biogas slurry on CO2 absorption performance of biogas slurry were investigated using the typical CO2 bubbling absorption system. Additionally, the feasibility of agricultural application of CO2-rich biogas slurry was also explored in terms of the change of phytotoxicity and total phosphorus concentration before and after adding exogenous CO2 absorbents. The results showed that ammonia nitrogen, the main harmful substance in the biogas slurry, could be removed by concentrating biogas slurry at vacuum conditions. And the removal efficiency of ammonia nitrogen could reach up to about 87.69% when the biogas slurry concentration was increased by 5 times. Compared with adding absorbents into the raw biogas slurry directly, adding the same absorbents with high concentrations into the concentrated biogas slurry could greatly improve the CO2 absorption capacity. In addition, when the concentrated CO2-rich biogas slurry was diluted so that the concentration of CO2 absorbent concentration was equal to that of the raw biogas slurry, the germination index （GI）of Chinese cabbage treated by the concentrated CO2-rich slurry was higher than that treated by raw biogas slurry. Moreover, adding exogenous absorbents in biogas slurry can help remove the total phosphorus in biogas slurry, which reduces the environmental hazards for agricultural applications. Among all of 6 exogenous absorbents, MEA has the comprehensive advantages in terms of improving CO2 absorpt

关 键 词：沼液 可再生吸收剂 厌氧发酵 减压浓缩 二氧化碳捕集 植物生理毒性 

分 类 号：S216.4[农业科学—农业机械化工程]