Brief introduction of heavy ash drying equipment

Wuxi printing factory, Wuxi printing, Wuxi translation, Wuxi translation company, Wuxi training, Wuxi printing, titanium dioxide, electrical ceramics, 95 porcelain, high frequency porcelain, stone like paint, epoxy floor paint, epoxy resin floor, fluorocarbon paint, epoxy resin floor are compared in this paper. Heavy soda ash has high density, moderate particles, small dust flying, not easy to scar and knot

This paper makes a comparison between steam rotary furnace and fluidized bed in drying heavy soda ash.

Heavy soda ash has the advantages of high density, moderate particle size, small dust flying, not easy to scab and save the cost of packaging and transportation. It can prolong the life of reaction furnace when it is used in steel making industry and glass production. Although the production cost of heavy soda ash is slightly higher than that of light soda ash, the production of heavy soda ash has been developed in many countries in recent years.

In recent years, the selection of drying equipment for heavy soda ash is compared in the relocation and transformation projects of major soda plants.

1 process comparison

1.1 steam rotary furnace

After the monohydrate is dried in the Steam Calciner, it is sent to the soda cooler through the powder transportation equipment, and the finished heavy ash is sent to the packaging. After dedusting and washing, the furnace gas is discharged by induced draft fan. See Figure 1.

Figure 1 flow diagram of heavy ash Steam Calciner

It is characterized by large production capacity, safe operation for a long time and low energy consumption per unit product.

1.2 fluidized bed

The construction investment of rotary furnace is relatively large. With the industrial application of fluidization technology, people want to apply the characteristics of strengthening heat and mass transfer of granular materials in the drying of alkali, and replace the rotary furnace with a static fluidized bed equipment. Since the late 1950s and early 1960s, the research on boiling calcination has been started. The monohydrate alkali enters the fluidized bed through the premixer. The monohydrate alkali is dried and cooled in the fluidized bed. The finished heavy ash is discharged from the lower end of the fluidized bed and sent to the packaging. The mass transfer power is the hot and cold air flow sent by the blower into the fluidized bed, and the alkali dust gas is removed by dry method. The product quality is good and the drying and cooling equipment are combined into one equipment for easy operation.

2 equipment and performance comparison

At present, 40 million tons / a heavy ash is taken as the calculation standard.

2.1 steam rotary furnace '

Two 3 000 × 20 000 mm steam rotary furnaces, two 8 687 × 2 064 × 1 600 soda coolers and powder transportation equipment were selected. The price of steam rotary furnace is 4.5 million yuan / set, the power is 132 kW; the price of soda cooler is 150000 yuan / set, the power is 45 kW. Sodium monohydrate is used for drying. 4 MPa steam. The steam consumption per ton of product is about 0.5 T; the cooling water for cooling heavy ash is about 3 T (at = 8 ℃). Since the return furnace gas only contains steam, a small amount of air and alkali dust, it can be washed and condensed to recover heat and water as hot alkali liquor for standby.

2.2 fluidized bed

Two sets of fluidized bed (6 300 × 4 400 × 13 000) and auxiliary equipment (including blower, air heater, cyclone and bag filter) and powder transportation equipment were selected. The price of fluidized bed and auxiliary equipment is 2.8 million yuan / set. The blower power is 560 kW.

3.1 MPa steam is used for drying monohydrate alkali, and about 0.52 t steam per ton of product is used for drying; 3.5 t is used for cooling water per ton of product (△ t = 5 ℃). In order to achieve good mass transfer effect in the fluidized bed, 220 ℃ hot air is needed to be fed into the drying section of the fluidized bed

Nm0 / h, and 7 000 nm0 / h air is fed into the cooling section. After dust removal, the temperature of the two streams of air discharged from the fluidized bed is about 11o ℃. In terms of the land area occupied by equipment layout, as the volume of fluidized bed and other equipment is much smaller than that of rotary furnace, the plant needs 33 m × 27 m, but the height of plant is 40 m due to the layout of dust removal equipment. .

To sum up, the rotary furnace has the advantages of long operation period, simple operation, low energy consumption, long equipment manufacturing cycle, high one-time equipment purchase cost and large floor area. Due to low plant height, civil construction cost is low. For fluidized bed, the equipment purchase cost is low. The equipment is static equipment, easy to maintain, high heat and mass transfer efficiency in bed, good heavy ash particles, ensuring product quality, small floor area, high civil construction cost and large energy consumption. Therefore, for heavy ash project in alkali plant, appropriate heavy ash drying equipment can be selected according to the specific conditions of relocation, new construction and expansion projects.