Dissertation > Excellent graduate degree dissertation topics show

Research on the Control of NH3and HCN during Microwave Pyrolysis of Sewage Sludge

Author: CuiYanNi
Tutor: TianYu
School: Harbin Institute of Technology
Course: Environmental Science and Engineering
Keywords: sewage sludge microwave pyrolysis NH3and HCN influence factors transformation mechanism
CLC: X703
Type: Master's thesis
Year: 2012
Downloads: 50
Quote: 0
Read: Download Dissertation

Abstract


Microwave pyrolysis technology for sludge has the advantage in thoroughly sludgereduction effect, high energy recovery rate, high organic conversion rate and effectivefixation of heavy metals. Besides these, the characteristics of the microwave improves theweakness of low heating rate, low heat transfer rate and uneven heating in the traditionalheating method, thus having a good application prospects. The organic matter in thesludge contains a large amount of N elements, and therefore will produce the NH3andHCN when producing high amount of combustible gases, this will have potential damagefor the environment and limit the application of the technology. So, it is necessary tofocus on the transformation law of nitrogen in the pyrolysis process in order to control thegeneration of NH3and HCN.This experiment is based on the dewatered sludge of Taiping Sewage TreatmentPlant, the subject of this research are the prepared dry sludge, de-ash sludge and sludgethat has addictive minerals. We conducted the research on the pollution control of NH3and HCN generated from the microwave pyrolysis process applied in the municipalsewage sludge. First, we studied the factor affecting the generation of nitrogen pollutiongases in the microwave pyrolysis processing, including the final temperature, heating rate,sludge moisture content as well as the inherent minerals and mineral additive. Then, westudied the internal mechanism of how the mineral will affect the generating of nitrogengases in the sludge microwave pyrolysis processing. Based on the research result of theaffecting factors, we got the optimum conditions in controlling the generating of nitrogengases and we also found the best pollution inhibitors. Based on this research, weconducted further research on the internal transformation mechanism of nitrogen gasesgeneration and we also analyzed the liquid products and gaseous products in themicrowave processing of sludge. We continued to study the controlling mechanism andthe pathway of generating gaseous product.The production rate of NH3and HCN is affected by the following factors: the finaltemperature of the sludge heating process, the sludge moisture content and the heatingrate in the pyrolysis process. The conversion rate of NH3and HCN is increasing with theincreasing of the final temperature, sludge moisture content and heating rate. In addition,mineral has a significant effect on the generating rate of NH3and HCN; The generatingrate of NH3and HCN from the acid ash-off sludge is much higher than the originalsludge; adding20%of Fe2O3and CaO has the best effect inhibiting the generation ofNH3and HCN. By detecting the liquid and gases production from the pyrolysisprocessing of both original sludge and sludge that has mineral addictive using GC/MS,we found that liquid products mainly contain amine state-N, nitrogen-containingheterocyclic-N and nitrile-N. As the pyrolysis temperature increases, inorganic nitrogen,protein-N, amine state-N, as well as nitrogen-containing heterocyclic-N and nitrile-N inthe sludge have a concessive thermal cracking, and accompanied by the formation ofNH3-N and HCN-N. After adding minerals, the pyrolysis of amine-N is affected and alarge number of NH3is generated, and make it generate N2and H2, the addition ofmineral also undermine the generating process of HCN and make it breaking down to N2.What’s more, iron elements can act as a catalyze of the generation of N2and H2fromNH3, calcium elements can make the HCN hydrogenated to produce NH3, and continue to serve as a catalyze of the production of N2and H2from NH3.

Related Dissertations

  1. Study on Fusion Characteristic and Mineral Change of Blends of Sludge and Coal,X703
  2. Research on the Regional Difference and Influence Factors of China’s Carbon Emissions,X502
  3. Spatial Analysis and Pollution Evaluation about Water Environment Actuality of Rural Surface Water in Typical Regions of Jiangsu Province,S271
  4. The Factors of Knowledge Sharing to Learners in Virtual Learning Community,G434
  5. Study on the Fertility Concept of Rural Married Women Borned after 1980,C924.21
  6. Of coal and municipal solid waste pyrolysis Resources Reuse,X705
  7. Study on Spalling Mechanism and Application of Coal Wall with Large Mining Height,TD355
  8. Survey and Study on Subjective Well-being and Occupation Stress for the Clinicians in Third-level Grad a Hospitals of Urumqi City,R195
  9. Influence Factors and Countermeasure Research on Students’ Join the Basketball Activities in Junior Middle School of Binzhou,G633.96
  10. The Influence Factors and the Countermeasures for Carrying Out Shuttlecock in Jinzhong Primary School,G849.9
  11. The Chongqing regional economic development differences evolved with the economic development of Chongqing,F127
  12. The Development Present Condition of College Extracurricular Bodybuilding Clubs Investigate and Research in Chang Chun,G807.4
  13. Empirical studies of short-term financing bonds of listed companies financial risk factors for,F832.51;F224
  14. Diagnostic Research on Failure Cost Source of Processing Garment Enterprises,TS941.8
  15. Research on the International Competitiveness of China’s Cultural Trade and Its Influence Factors,F224;G125
  16. PE teachers Qinghai health status and interventions,G807.4
  17. Research on Factors of the Differences of Service Industry’s Concentration Degree in Jiangsu Province,F224
  18. The Research on the Current Implementation Status of Offering Biological Elective Course in Senior Middle School,G633.91
  19. A Study on Influence Factors of the Rural Junior Middle School Biology Teachers’ STS Teaching Conceptions,G633.91
  20. The Observation and Analysis on Teaching Tact in Biological Classroom of Senior High School,G633.91
  21. Substantial Evidence Research on the Employee Satisfaction Degree in Nanjing Hotel,F272.92

CLC: > Environmental science, safety science > Processing and comprehensive utilization of waste > General issues > Wastewater treatment and utilization
© 2012 www.DissertationTopic.Net  Mobile