The Study On Deliquescence Of Aluminum Phosphide And Harmless Disposal Of Fumigation

Phosphine is a kind of fumigant,which is widely used in food and tobacco industries at present.It has some advantages such as wide pesticide pedigree,good insecticidal efficacy,few remnants and low fumigate fees. This thesis uses phosphine as its research direction and has studied the influences of different factors on the rate of formation and degradation rate of phosphine.It has also researched how the grain quality is affected by the degradation of phosphine and tested the deliquescence of the phosphine in model bin.The results of the studies are listed as follows:Temperature, relative humidity, deliquescence state can all impact the deliquescence rate.If other factors are equal,in three different temperatures(20℃、25℃、30℃),the increased environment temperature can improve the deliquescence rate,so the rate is the fastest in the factor of 30℃;Under the conditions of four different relative humidities(33%、53%、75%、85%),the highest one produce the fastest rate,that is to say,if the growth rate of phosphine is the fastest,the relative humidity should be 85 %;In three deliquescence states,the effects of aluminum phosphide in bags are the slowest,while no debris covered ones are the fastest.In the process of phosphine’s degradation,the initial concentration,ozone ultraviolet lamp power,temperature,relative humidity all concern the time’s duration of the degradation.In the three initial concentrations(100ml/m3、 200ml/m3、400ml/m3),the higher one need the longer time;In the three lamp powers(40W、80W、120W),the largest one can produce the quickest reaction;Among the three temperatures(20℃、25℃、30℃),the phosphine’s concentration reduce faster under the condition of 30℃;In the four different relative humidities(33%、53%、75%、85%),the highest humidity will make the degradation velocity reduce.In the wheat and maize storage equipment,we use ozone ultraviolet lamp to degrade phosphine.As a result,under the influence of ozone ultraviolet lamp and phosphides,the two grains’ viability and germination rates remain the same,and in a given storage period of time they are still not impacted.However,to some degree,the fatty acid values of the wheat and maize have increased comparing with the original samples.During the test of the phosphine deliquescence,we have found in the actual fumigation conditions,the deliquescence rate is lower than the rate under the experimental conditions.This is because we have used too much aluminium phosphides to make the deliquescence rate reduce,and the temperature and humidity were too imbalance and uneven circulation to lead the rate fluctuate considerably,at last we get the Inaccurate test data. In the actual fumigation conditions the air under the forced convection bring about the water vapor constantly,in the meantime,it take away the produced phosphine gas,so the high concentration cannot be formed and the process will be more secure.From the production data,it is clear to see the maximum concentration rate of the phosphine gas out of the deliquesce is 732ml/m3 at most.Adopting the deliquescence method,the maximum concentration rate of the phosphine is far below its critical value of blasting(26 g/m3 or 18200 ml/m3).Employing the “Dynamic Deliquescence Method” correctly during the process of fumigation is safety,effective and feasible.