Method for purifying phosphine tail gas from fumigation

Abstract

This invention discloses a method for purifying phosphine tail gas by fumigating, which belongs to the filed of air purification. The invention provides a method for purifying the phosphine fumigating tail gas, which comprises the following steps of: irradiating the phosphine fumigating tail gas by a vacuum UV light source for converting the phosphine intophosphoric acid; and then, causing the tail gas to pass through an active filter for absorbing the phosphoric acid and decomposing ozone . The method has a high efficiency of purifying the phosphine, low energy consumption , large air flow processing amount and a simple process. The application of the invention can be used in processing phosphine fumigating tail gas in large air flow and has a higher practical value.

Description

technical field [0001] The invention belongs to the technical field of air purification, in particular relates to the purification of low-concentration phosphine in the air, and is mainly used for the treatment of phosphine tail gas during fumigation and pest control of tobacco and grain storage. Background technique [0002] In the storage process of agricultural products such as grain, tobacco, medicinal materials, dried fruits, etc., various pests are easy to breed. Using phosphine to fumigate the storage warehouse has good insecticidal effect, convenient use, low cost, less residue and non-toxic residue. It is the safest fumigant, and phosphine is used as the only fumigant in many countries. [0003] Phosphine is a highly toxic gas. After fumigation, the air containing phosphine in the warehouse is discharged directly without treatment, which may cause harm to surrounding people or animals. If it is not discharged, low-concentration phosphine will be released in the air ...

AI Technical Summary

Problems solved by technology

The purification efficiency of phosphine is directly related to the concentration of oxidant. In order to achieve higher purification efficiency, the amount of oxidant should be much higher than that of phosphine, resulting in waste of oxidant

In the Chinese patent (ZL 200610048889.6), a purification method of phosphine is mentioned, which uses an aqueous solution or acid solution containing Cu and Pd as a catalyst, which can be recycled and reduces operating costs, but it needs to be oxidized in the phosphine absorption catalyst It is difficult to switch between regeneration processes and recover catalysts

Chinese patent (ZL 93101650.9) mentions an activated carbon impregnated with Cu, Hg, Cr, Ag, which can be used for phosphine and arsine produced in the semiconductor industry, but the protection capacity is limited

Chinese patent mentioned Ni ion impregnated adsorbent (application number 200910094498.1), or Cu ion impregnated adsorbent (application number 200910094501.X), or Co ion impregnated adsorbent (application number 2009 1 0094502.4), or alkaline earth metal halide impregnated Molecular sieve adsorbent adsorption, (application number 200810058666.7), although there is no need to add accelerators such as noble metals (AgO) or heavy metals (Hg0, Cd0), but the adsorption capacity is too low, and the adsorption capacity of phosphine per gram of adsorbent is less than 20mg , poor practicality

[0007] Patent CN 1 398658A (publication number) discloses a method for purifying yellow phosphorus tail gas by catalytic oxidation in a fixed bed, and has developed a series of catalysts for catalytic adsorption of phosphine impurities. The active components on the surface react to form phosphorus trioxide and phosphorus pentoxide, and the adsorption capacity of activated carbon to phosphorus trioxide and phosphorus pentoxide is much larger than that of phosphine to realize the deep purification of yellow phosphorus tail gas. The disadvantage is that oxygen or air needs to be strictly quantitatively added to the yellow phosphorus tail gas, which increases the difficulty of operation and control

[0008] In addition, the patent CN 101559322A (publication number) proposes a phosphine ultraviolet photodegradation method, but the treatment device established by this method is difficult to apply to the purification of phosphine gas with a large air volume, and the product after photolysis will be refluxed if it is not treated In the warehouse, it can still cause harm to the facilities in the warehouse

[0009] In short, the current phosphine treatment process is mainly based on wet oxidation, the operation process is complicated, the treatment air volume is small, and the product treatment is difficult. Although the dry adsorption process is simple to operate, the adsorption capacity of the adsorbent for phosphine is small and cannot scale application

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