Waste acid regeneration unit

Project name: waste acid regeneration unit

Customer name: zhejiang yuan group

The nature of the project: new project

Undertake: Beijing JieRui general contracting

A time: on September 18, 2009

Production: production on time

Operation: in good condition

Waste acid regeneration principle and process:

Hot rolled steel plate after hydrochloric acid pickling, can for cold rolling. Hydrochloric acid pickling, iron and steel plate surface oxide by hydrochloric acid wash, the consumption of hydrochloric acid into is given priority to with FeCL2 chloride, dissolved in hydrochloric acid solution, with the pickling process, iron ion concentration of acid lotion will rise, and free of HCL concentration reduced accordingly. To keep free of HCL concentration of acid pickling, increase of iron ion in removing acid, waste acid, acid regeneration device to generate free acid, return pickling, recycle waste acid regeneration process, at the same time get iron oxide powder.

Pickling process such as chemical reaction equation of the following:

Fe 2 + HCL = FeCL2 + H2

FeO + HCL = FeCL2 + 2 H2O

Fe2O3 HCL + 2 = FeCL3 FeCL2 + + H2O

Fe2O3 fecl3 HCL + 6 = 2 + 3 h2o

2 fecl3 + Fe = 3 fecl2

4 fecl2 + 4 HCL + O2 = 4 fecl3 + 2 h2o

From the waste acid pickling line, collected in the waste acid tank, with waste acid pump after waste acid filter into to the concentrator (flow pneumatic - valve automatic control). Waste acid through to the concentrator circulating pump to spray to the top of the concentrator. With furnace gas from roaster direct heat (400 ℃), some water evaporates from the waste acid, waste acid concentration are obtained. After enrichment of waste acid by waste acid by baking furnace feed pump station, to the top of the roaster, then through spray rod, to make spray nozzle into the calciner. Roaster is equipped with the spray gun, each pole on the spray gun is equipped with multiple nozzles, spray gun can be automatically inserted inside the roaster.

Roaster ontology is a steel shell, lining refractory acid-proof brick, on the ontology is tangent to decorate 2 burner heating, drying to the concentrated acid drops from the nozzle, and in the hot area of the roaster (500-800 ℃), FeCL2 and FeCL3 decomposition according to the following equation:

2 fecl2 + 2 h2o + o2 = 1/2 Fe2O3 HCL + 4

Fecl3 2 + 3 + 6 h2o = Fe2O3 HCL

Solid particles (Fe2O3) in the form of powder fell in baking furnace bottom cone, with a rotary valve discharge, rotary valve can make the internal with external gas roaster. In the upper portion of the rotary valve installed a oxide block of crusher. Used for broken from baking furnace wall mass.

Baking furnace gas by combustion gas, water vapor and hydrogen chloride gas composition, leave the roaster and through the cyclone separator from the top of the roaster will contain Fe2O3 powder most of the separated. Oxide isolated by rotary valve to discharge, and return to the roaster. And then roasting gas entering to the concentrator, in to the concentrator, the high temperature gas directly contact with circulating acid, and cooling and cleaning gas in the residual only a small amount of oxide, and into the absorption tower.

Absorption of hydrogen chloride gas furnace with rinse water. Rinse water through the nozzle to the absorption tower from entering, the water is evenly distributed in the absorption tower packing. In the reverse flow, form regenerated acid gas is absorbed in the hydrochloric acid composition, regenerated acid from absorbing acid storage tank bottom gravity to regeneration.

Furnace gas containing trace HCL left, from bottom of absorption tower through the exhaust fan (fan impeller with industrial water cleaning, cleaning equipment, cooling effect) into the washing tower.

After the exhaust fan is a droplet separator, here to separate gas and liquid. Furnace gas containing trace HCL scrubber in the lower part of the rinse water washing, with the desalting water washing in the upper portion of the washing tower.

Exhaust fan is in a state of negative pressure in the system, ensure that there will not be leaked hydrogen chloride in the system.

Baking furnace in the production of iron oxide powder by a pneumatic conveying system to the iron powder bin, the bin the upper part of the installation has a plastic plate type dust collector to clean burning of used air conveying Fe2O3, then air emissions into the atmosphere. At the bottom of the bin by the gate valve type discharge Fe2O3 powder into bag bag filling machine.

Major industrial process parameters, i.e., temperature, pressure and flow rate in the control room by digital display, and important operating parameters are automatically by PLC automatic control system, the start of the equipment, control and parking can be performed by the keyboard. Alarm and functional errors by an independent alarm memo record, therefore, the operator can easily check from the control room equipment running status, and report provided by the printer class.

Regeneration device of the electrical drive and automation instrument, used to guarantee normal operation of system and simplify the operation. PLC control system can be guaranteed under the condition of the system appear any fault can be timely reflected, can connect to the automatic alarm, automatic stop. In the case of a trouble-free, can reflect the system's normal operation. In the case of equipment failure, regeneration unit can automatically stop running.

The start and stop the operation of the unit, can be carried out at any time, start the device, with burner, heating and water operation, to reach the right flow, temperature and pressure, and then supply, water supply switch to acid regeneration can begin, to stop the equipment running, the truncation acid supply, equipment operation, automatically switch to the water after a period of time, regeneration unit stop completely. The unit has three functions: new water (for cleaning the roaster), flushing water operation (baking furnace heat load, clean pipeline), acid operation (production).