UASB pulse influent water distributor used in the production of devices can be divided into intermittent (pulse), continuous, continuous and intermittent combined with other ways; from the cloth pipe form a porous tube, a tube hole and branched forms.
(1) continuous feeding mode (one hole)
In order to ensure the uniform distribution of the influent, each inlet line is connected with a water inlet point, which is the most ideal condition (Fig. 3a). In order to ensure that the flow of each water point is equal, the proposed use of water tank (or channel) above the reactor to allocate, through the channel or distribution box between the triangular weir to ensure that the same amount of water. The benefit of such a system is the easy observation of blocking situations.
2) pulse inlet mode
The most prominent characteristic of UASB reactor in our country is that it adopts pulse water inlet mode. Some researchers think that the pulse way of water, so that the bottom of the sludge alternating contraction and expansion, to help the bottom of the sludge mixture. Figure 3a is a kind of pulse water distributor used in Beijing ring Academy. The system is based on the water distribution mode of Siphon Filter in water supply.
3) a tube of porous water distribution
Water distribution in the bottom of the reactor with water distribution in the horizontal pipe, in order to water distribution uniformity, the water flow rate is not less than 2.0m/s. The water distributing mode can be used for pulse water inlet system. A porous tube type water way problem is prone to clogging, therefore, should be avoided as far as possible in a tube with too much orifice.
4) branched water distribution mode
The characteristics of the water distribution system with water pipes with longer increase resistance, in order to achieve the purpose of uniform water distribution (Figure 3C). According to the author's practice, the maximum load area of the branch water distribution system is 54m2. The water distribution uniformity of large resistance system is good, but the head loss is large. Small resistance system, if the head loss is small, if it does not affect the processing efficiency, can reduce the complexity of the system.
Other types of water distribution, China also has a lot of experience in design and operation. And three phase separator, the different types of water distribution device, it is difficult to compare the merits of the worse. In fact, all types of water distributor have successful experience and performance.
3, water distribution pipeline design
The gravity water distribution, may be inhaled air sewage into the reactor through the triangular weir, will cause the inhibition of methane bacteria; into large amounts of gas and biogas produced will form a mixed gas explosion; at the same time, too many bubbles may also affect the precipitation. Because, more than 2.0mm the diameter of the bubble rising by about 0.2 ~ 0.3m/s speed in the water, the larger the diameter of the liquid part of the vertical velocity in the pipeline is lower than this value, may be appropriate to avoid more than 2mm the diameter of the air bubbles into the reactor, but also can avoid air resistance. At the bottom of the reactor with a smaller diameter, the formation of a high flow rate of strong disturbance, so that the water and sludge mixed to strengthen.
|
