Research On Mobile Corn Straw Pyrolysis Carbonization In-situ Field Return Equipmen

After consulting a large number of documents and research,based on the current research situation of mobile pyrolysis equipment at home and abroad,and in view of the needs of mobile pyrolysis and carbonization in-situ returning equipment,this paper carried out structural design and validation tests based on corn stalk,and designed a kind of equipment that can be used for field carbonization stalk in-situ returning to the field,the specific contents are as follows:（1）Based on the demand for in-situ carbonization and return of corn stalk to the field,a system process of stalk self heating carbonization,clean combustion and reuse of pyrolysis gas,cooling and cooling of biochar,and direct return of biochar to the field is proposed.Key parameters such as system processing capacity,pyrolysis temperature,reaction time,and air distribution coefficient are designed and calculated,and technical indicators of each system are clarified.Overall process plans such as clean emissions and self-sufficiency of carbonization energy are formulated.（2）Based on the principle of stalk internal heating low oxygen carbonization,we have developed a self heating reaction system,developed key components such as a pyrolysis carbonization reactor,a clean combustion chamber for pyrolysis gas,a stirring and compaction system,and a cooling and carbon production system.We have integrated stalk picking and collection,crushing and transportation,gas recycling and torrefaction,and biochar in-situ returning technology,and developed mobile pyrolysis carbonization in-situ returning equipment.（3）After the prototype is trial-produced,the prototype performance test is carried out.The results show that the raw material treatment capacity of the equipment is 50kg/h,the yield of carbon was 21%,and the conversion efficiency was 74.6%;the mass concentration of NO_Xand SO₂in gas were 184 mg/m³and 26 mg/m³;respectively,the mass concentration of particulate matter is 17.8mg/m³,meet the gas emission requirements of<GB13271—2014 Emission Standard of Air Pollutants for Boilers>.Through the impact test after the biochar is returned to the field,it is obtained that the content of total carbon,fixed carbon and metal elements in the biochar and the amount of biochar returned to the field comply with the requirements of stanrd of grade I biochar in<DB21/T3314-2020 Technical Specification for Direct Biochar Return to the Field>.After the biochar absorbs water under the same environment,it has a certain water retention effect,which is about 9%higher than the control group,Through pot experiment,it was found that biochar returning to the field had a positive effect on soil moisture and plant growth,and the soil moisture content increased by about 40.3%after adding biochar.This shows that the equipment can realize the functions of low carbon emission,carbonization energy self-sufficiency,field operation,etc;In addition,it can improve soil fertility,maintain water and moisture,promote plant growth,improve agricultural economic benefits,and provide a support platform for stalk returning to the field.