Dish acid distributor is an invention patent and short for multi-dish liquid distributor applied in sulfuric acid device, which can be widely applied in tail gas purification for coal-fired power plant and large-scale chemical plant of oil refining, petrochemical and fertilizer. Scaling effect of large packing tower is mainly caused by uneven flow of distributing points. On the contrary, this effect does not occur for multi-dish liquid distributor, so that liquid can be even distributed.

Dish acid distributor is consisted of six parts including feed header, feed branch, distributing pipe, orifice plate, distributing dish, downcomer. Distributing dishes are cylinder type while the distributing section is in square except dishes on the periphery of tower. The dish and square section are concentric. In general, in each dish there are 16 or 30 pieces of downcomers, which form square or triangle on packing surface. For example, 16 pieces of downcomers are 4x4 arranged, namely square arrangement (exactly right triangle arrangement); 30 pieces of downcomers are 5x6 arranged, namely isosceles triangle arrangement with 62°vertex angle. These downcomers from dishes bottom extending to downcoming point can carry acid to packing surface. Each dish connects to one distributing pipe, which connects to feed branch or header. After flowing out from distributing pipe located at dish center, acid then radially flows to downcomers. And quantity of dishes depends on tower diameter and density of distributing point.

Dish acid distributor has two stages flow control. The first stage is realized by orifice installed in distributing pipe, and it can control acid flow feeding into dishes. In other word, the same orifice the same flow. The second stage is realized by overflow trough and holes  on  the downcomers.

The most outstanding feature of dish acid distributor is circular flow. Acid flow direction in dishes presents two kinds of flow, radial flow and circular flow. Radial flow occurs from outlet of distributing pipe to downcomers. Meanwhile circular flow occurs between wall of dish and outer of distributing pipe. In this case, circular flow can balance fluctuation of radial flow and flow difference between downcomers, which not only increases adjusting range of flow, but also reduces flow difference between downcomers.

After evenness of distributing acid is improved, spraying density will be reduced, which is benefit for efficiency of drying and absorbing because of increasing acid temperature of tower outlet. For evaporation of fine droplets is the control step of drying efficiency, reducing temperature difference between gas and liquid at tower bottom is able to reduce chemical mist content and increase acid mist size.

There are two dishes per square meters on tower section. Meanwhile each dish has  small  base  area  that  has  a  little influence to upflow and can make lower height of unloading packing under dishes. And height of each dish is half of trough, so that total height of distributor is lower. In addition, downcomers have been installed in dishes in shop and almost do not need extension pipes. Furthermore, operating weight of this distributor is lighter, and total acid amount in dishes is less than one-tenth of that in distributing trough.

Dish acid distributor has the characteristics of distributing evenness, wide range of adjusting flow, light weight, no scaling effect, and easy installation and maintenance, which  resolves  bad  evenness  of  existing  distributor,  much  mist  and  easy block for tubular type, more large more uneven for trough type.

◆  Distributing evenness: Even distributing without peak and valley value of existing distributor, flow difference between downcomers <2% and distributing density more than 50 points/m2.

◆  Wide range of adjusting flow: Adjusting range 30~120%

◆  Good blocking resistance: This is benefit from circular flow of sulfuric acid in dishes.

◆  Low occupation: Height of each dish <0.5m

◆  More material selection: It can be fabricated from traditional and new materials.

◆  Easy installation and maintenance: Height of each dish is half of trough, and has lighter weight. It can be moved by one  person and easily installed and maintained.

◆  Low cost: Light weight and less material lead to lower cost comparing with existing distributor.