Filters in a dilute acid purification solid-liquid separation of application

Jinchang smelter existing 3 series of acid and device used to deal with Mr Type matt furnace and the copper smelting gas production of sulfuric acid, and the annual 98% H2SO4 capacity of 420000 t. Among them, I series acid purification steps the adiabatic evaporation device, flue gas directly to the cooling dilute acids cleaning process, the main equipment free tower, efficient scrubber, packing tower, heat exchanger, level 1 electric demisting precipitator; 1 I series acid purification steps the adiabatic evaporation device, flue gas indirect remove heat diluted acid washing technology, the main equipment free tower, packed tower, between the tanks, level 1 electric demisting precipitator; Ⅲ series acid cleaning process device USES dynamic wave adiabatic cooling, weak acid washing process, the main equipments are level 1 power wave scrubber, gas cooling tower, two levels of electricity combination in the fog. Design the acid strong for 5% ~ 15% of dilute acid purification, the aim is to reduce flue gas temperature, remove dust in flue gas, acid mist and harmful substances (As, F, etc), after purification of dilute acids, due to pollution, and part of the (hereinafter referred to As extractant) to remove processing, most of the return to use.

By a flue gas purification process and equipment conditions, the limit, 3 series to remove every day can nearly 3 000 m0 to deal with, to remove after purification of dilute acids solid impurities. The use of traditional settling tank solid-liquid separation, as the subsidence area is small, the liquid in the slot for a short time, the vast majority of solid particles in the sink before they are clear liquid into circulation in the slot, caused by the results of settling tank bottom flow (unclean acid) contain slag low (1 ~ 2 g/I), filter press pressure! Don't; On the other hand, suspended particles back with smoke, from circulation slot, electricity demisting precipitator eduction, cause environmental pollution, air tower nozzle often appear jams, influence r E often production.

Jian ten purification weak acid washing, jinchang smelter decided to try out a 3300 Ⅱ CN type filter (1) alternative treatment T series settling tank cleaning process DaChu empty of reclamation.

1 CN filter

1.1 the work principle and the structure

CN filter the inclined plate flocculation precipitation, polymer particle layer absorption filter technology, will be discharged suspended in retaining down, realize the solid-liquid separation. Its working principle is: (1) and flocculant the mixture of reclamation in filter in the settlement of the inclined plate, which greatly part of sedimentary to suspend a regular eduction in sludge; (2) the fine particles floating with the liquid into the upper polymer particle adsorption layer and interception down, clear liquid natural through, and the overflow from mouth outflow; (3) and by compressed air reverse wash, reverse wash, to the gas chamber internal filter with curtilage gas, then suddenly breaks gas, make the filter internal in negative state, the upper clear liquid rapidly down into the filter medium layer, cleaning surface sediments, avoid filter congestion and scaling, to ensure the long-term filtering effect. Equipment for the whole structure of glass fiber reinforced plastic, the schematic diagram a few institution figure 1, 2, 3.

1.2 the main equipment and instrument

Ⅱ CN type filter: led 3 300 mm X 4 500 mm, 1 (filter medium capacity: 4 m X 0.5 m);

Flocculant prepared slot: string of 1 200 mm multiply one 700 mm (to design an automatic control level of gas mixing preparation slots), Taiwan 2;

Liquid-vapor separator: + 500 mm X 1 500 mm, 1;

PAM flow meter: 400 I/h, 1 only.

Figure 3 CN filter internal schemes

Note: this is labeled height, diameter size proportion is not.

2 application

2.1 process flow

From the DaChu empty to purify the DN450 dilute acids glass steel tube into the circulation slots. In the process, with a tube will be part of the weak acid leads into their gas and liquid separator removal from the gas within, and adding flocculant before for mixed flocculation, then the mixture into the strainer on the settlement, the filtering; The clear separation on liquid (dilute acids) most of their to dilute acids circular trough recycling, small part to lead off the filtrate slot as unclean acid treatment, the regular flow from the filter, the pressure filter made lead residue dehydration, process flow as shown in figure

2 application

2.2 application effect

Ⅱ CN type filter and its complete a 3300 device on oct. 13, 2005 feeding trial production, operation has been stable, filter cap did not appear jam phenomenon, from the qing qing transparent liquid on the track, the majority of the return cycle use groove, reduce the pollution acid emissions, from the bottom flow (unclean acid) slag content an average of 1% ~ 2%, and ensure the acid treatment system and lead filter press run normally, I series purify air tower jam phenomenon for significantly less. Operation, design the index comparison see table 1.

3 in the operation of the existing problems and solutions

(1) the original design flocculant solution concentration is 0.1%, and the solution by adding amount of float flowmeter to control, the effect of adding system pipeline plugging, then through a period of exploration, has no impact on the separation effect, the solution concentration moves to a 0.05% ~ 0.07%, and solve the pipeline jams.

(2) about CN 1 I a 3300 type filter, jinchang smelting plant and equipment manufacturers at first agreed to try out agreement, and in the design of drainage measures not filter full consideration, currently USES artificial drainage, on the separation effect can produce certain effect. Suggest perfecting the sludge emission monitoring measures, do automatic decontamination.

(3) for the separated on the liquid (dilute acids), about 1/10 into the lead-off filtrate slot as unclean acid treatment; The rest return cycle slot as dilute acids reuse, but what exactly proportion by how much depends not only on the purification dilute acids content slag, but also by purification arsenic in dilute acids, fluorine content, this needs to be further practice and exploration.

(4) with three series of sulfuric acid every day have a lot of reclamation to deal with, only 1 CN 1 I a 3300 type filter processing not over, its efficiency can not be completely come out now, at least 1 to rid completely absorbed.

4 last word

Through trial, the CN a type 3300 filter with corrosion resistant, stable performance, small amount of maintenance, low cost, filtration separation effect is good, energy conservation and environmental protection etc, and colleagues is worth using for reference.