Soda production of soda alkaline process flow
Soda production of soda alkaline process flow
Bases can be divided according to the production process of carbon filter, compression, calcination, heavy ash, heavy ash packaging, crystallization, refrigeration, dry ammonium, dry ammonium packaging 9 processes.
A: carbon filter process
Carbon filtration processes include carbonization, filtration, comprehensive recovery of several processes.
1, carbonization process
Carbonization process is the use of ammonia liquid ammonia II in the carbonation tower to absorb CO2 generated NaHCO3 crystals while generating NH4Cl process. The reaction in the carbonization tower can be expressed by the equation NaCl + NH3 + CO2 + H2O → NaHCO3 + NH4Cl. Carbonized tail gas contains a large amount of ammonia, to be recycled after comprehensive recovery; carbonization process is an exothermic reaction process, the reaction process has a large amount of reaction heat needs to be removed.
Take carbonation out of the tank to the filter tank, the gas phase also contains a large amount of ammonia to be induced by the induced ammonia to clean ammonia net ammonia after the vent; above the filter and the MI barrel of air at the same time purify the net ammonia and venting.
2, filtering process
The filtration process utilizes the principle of vacuum filtration to separate the NaHCO3 crystals in the carbonization removal solution, and at the same time, the NaCl content in NaHCO3 is reduced by washing water; the filtrate is removed to MI barrel and NaHCO3 crystal to be calcined;
3, a comprehensive recovery process
Comprehensive recovery is mainly recycled carbonation, filter exhaust and calcined condensate ammonia; the same time, water recycling. After comprehensive recovery of carbonized exhaust venting, the exhaust filter after the comprehensive recovery to the compression process;
Second, the compression process
The compression process includes both compression and vacuum. Compression is compressing 98.5% and 68.77% of CO 2 recovered by the compressor and compressing the recovered calcined gas. After cooling, the medium and low sections are sent to the carbonization tower. Vacuum is the use of vacuum suction filter exhaust venting, played a continuous stable operation of the filter role.
Third, the calcination process
Calcination process using steam in the calcining furnace heating carbonization process sent over the NaHCO3 crystal decomposition to produce Na2CO3 finished while the furnace gas recovery washing process. The following chemical reactions take place in the calciner: 2NaHCO3 → Na2CO3 + H2O + CO2 Because of the large amount of CO2 gas, ammonia gas and alkali dust in the calciner gas, CO2 gas and ammonia gas are the raw materials for the production of alkali. The alkali dust recovery and Is a product; and if not recovered, these gases not only pollute the environment, but also increase the production cost. Therefore, calciner gas must be recycled. Recycling also requires cooling and washing.
Fourth, heavy gray process
Heavy gray process is the use of hydration crystallizer light soda ash in the mold to produce an alkali reaction, and then dried in a fluidized bed to generate large crystalline particles of heavy soda ash. The flow chart is shown in the following block diagram.
Fifth, soda ash packaging process
According to product quality and customer requirements, soda ash packaging is divided into light soda ash packaging, heavy ash packaging, heavy gray powder packaging;
Six, crystallization process
The crystallization process is a process in which MI sent from the carbonization process is subjected to ammonia absorption, cooling, salt addition and the like to cause the ammonium chloride to crystallize and separate the crystals into the ammonium chloride product. The specific process can be divided into AI process, MII process and ammonia system cycle. The AI process is specifically as follows: the MI sent from the carbonization process is introduced into the cold crystallizer through the water-cooling and heat exchange with the MII through the ammonia absorption process (the cold crystallizer is cooled down by the external cooler) and overflows into the salting-out crystallization ; Crystallization generated in the crystallization of ammonium chloride crystallized from the bottom of the crystallizer. In the salting-out crystallizer, NaCl is added to produce ammonium chloride crystals and then pumped into the crystallizer.
MII process specifically: MII by the converter and AI heat exchanger into the ammonia absorber after ammonia into the AII clarifier overflow into the AII barrel, and then sent to the pump by the carbonization process. Ammonia system process specifically as follows: liquid ammonia from the liquid ammonia tank through the liquid ammonia circulation tank into the external cooler and the mother liquor indirect heat transfer heat absorption after the evaporation of ammonia into the ammonia separator, part of the ammonia to ammonia, another Part of the ice machine to become condensed liquid ammonia loop after use.
Seven, refrigeration processes
Refrigeration process in the crystallization process has been introduced, the process is similar to the previous figure, this is not another presentation.
Eight, dry ammonium process
Dry ammonium process is separated by centrifuge 5% moisture content of wet ammonium chloride in the fluidized bed with indirect heating steam (while hot air) to make ammonium chloride water to reduce the dry process of ammonium chloride .
Nine, dry ammonium packaging
Dry ammonium according to different packaging requirements are divided into sacks, pouches and wharf packaging terminal packaging several
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