Composting equipment usually refers to the reactor device for biochemical reaction of compost, which is the main component of composting system. Its types are vertical composting fermentation tower, horizontal composting fermentation drum, silo composting fermentation bin and box composting fermentation tank. Vertical composting fermentation tower can be divided into vertical multi-layer closed and door type, vertical multi-layer pulp blade scraper type and vertical multi-layer movable bed type. Silo-type compost fermentation silo can be divided into silo-type static fermentation silo and silo-type dynamic fermentation silo. Box-type composting fermentation pond can be divided into rectangular fixed pear overturning fermentation pond, fan bucket overturning fermentation pond, crane overturning fermentation pond and horizontal pulp leaf fermentation pond.
Classification according to ventilation mode
At present, the main composting methods used in the world are thermophilic aerobic composting, which can be basically divided into three types: static forced ventilation composting, intermittent dump forced ventilation composting and continuous dynamic forced ventilation. The purpose of all kinds of methods is to make garbage harmless to the target, after full ripening, for fertilizer use. The choice of methods depends on the composition of garbage and local investment capacity.
1. Fermentation device with static forced ventilation
Static forced ventilation composting requires that it be carried out in a closed fermentation tank. The pool is square, circular, rectangular, inverted cone and so on. The selection of fermentation tank shape is determined by the way of feeding and discharging. The height is generally 3-4 M. The sealing of fermentation tank is beneficial to the control of fermentation conditions and the realization of harmless indicators. The bottom of the fermentation tank is provided with ventilation and drainage pipes, which can be shared. A vent is arranged on the top of the pool to discharge the exhaust gas and deodorize it. Ventilation can also be achieved by suction at the bottom, resulting in negative pool pressure. This method is conducive to the control of odor. Centrifugal fans are generally used for fans with wind pressures ranging from 53.32 kPa to 66.65 kPa and air volume per cubic meter stack from 0.1 to 0.2 m3 (standard)/S. Static forced ventilation fermentation has shorter fermentation period than anaerobic fermentation because it is aerobic fermentation. However, due to the static state of garbage, material and microbial growth are not uniform. Therefore, composting still needs a long fermentation period, especially for garbage with organic matter content higher than 50%, which makes static forced ventilation difficult, and easily leads to anaerobic state and prolonged fermentation period, which is its limitation.
2. Forced Ventilation Fermentation Device for Intermittent Turnover
Intermittent dump composting with forced ventilation is to use dump machine to dump garbage with high organic matter content in the process of composting. On the one hand, it prevents the agglomeration of composting materials to keep them loose and ventilated, on the other hand, it promotes the uniform mixing of composting materials, so as to add more garbage. Fast fermentation process, shorten the fermentation cycle. Tire dumper and caterpillar chain harrow are used in open stack, plate conveyor dumper of track rotor dumper of tank fermentation tank, rotary paddle of circular multi-layer fermentation tower and cylinder scraper, and bridge-type vertical agitator drill of cylindrical closed fermentation tank. And so on.
3 Continuous Dynamic Forced Ventilation Fermentation Device
Continuous dynamic forced aeration fermentation device is one of the most widely used devices in high-speed composting system at present. Dano fermentation drum is used for fermentation. The device is suitable for mixed fermentation of garbage with paper (35%-40%) and carbon-nitrogen ratio as high as 70. Normally, the cylinder rolls continuously at a speed of 3 r/min, and air is introduced to extract the gas from the other end, then deodorize. Dano fermentation drum has a diameter of 3-5 m, a length of 20-70 m and a power of 55-100 kW. Dano fermentation drum can complete the first fermentation in 28-48 hours, and feeds continuously at one end and discharges continuously at the other end.