Test and analysis of heat transfer in steam disinfection of matrix soil

Soil disinfection is a key link in the planting of facilities that directly affects the yield and quality, and steam disinfection is the most environmentally friendly and reliable disinfection method, this paper studies the heat transfer effect of steam in the substrate soil of the facility. In the course of the experiment, by building a test platform for the heat transfer performance of the substrate soil, the influence of the vent depth, steam entry time, steam pressure and soil moisture content on the lateral and longitudinal heat transfer effect of steam in the soil was studied, and the variation of soil temperature with time between the generation device and 1 h was explored. The results showed that the soil heat transfer effect was the best when the needle outlet pore depth was 160 mm, the steam pressure was 0.4 MPa, and the steam inflow time was 8 min. And the higher the soil moisture content, the better the heat transfer effect was. Under the best factor conditions, the soil temperature can quickly increase to the maximum value when the steam inflow time is 8 min, and it can basically be maintained above 60 ℃ after 30 min while meeting the disinfection requirements. After determining the optimal parameters of air outlet depth, steam inflow time, steam pressure and soil moisture content, a cover-type multi-needle steam disk with a movable soil steam disinfection machine is designed according to the actual disinfection requirements.