Biogas pretreatment device before use

The utility model discloses a pretreatment device for biogas before use. During use, raw materials needing to be treated are fed into the working bin through facilities and equipment such as a forklift or a screw; water or biogas slurry and the like are injected into the working bin to dilute the materials, then the driving motor is started to drive the stirring rod to stir and smash the materials, due to the fact that the rotating speed of the stirring rod is low, sand in the materials is prone to precipitation in the cleaning box, and the precipitated sand can be discharged from the sewage outlet. Simultaneously, materials are discharged into the fence through the electromagnetic valve; then, larger impurities in the materials are removed under the action of the fence; and therefore, blockage of a pump and a pipeline and winding of equipment such as a stirrer caused by large sundries in the subsequent operation process are avoided, a water pump is controlled to pump liquid chemicalsin an alkali liquor tank