Salt consumption of caustic soda
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This post was last edited by sunjl1981 on 2013-1-6 at 22:40. I have a standard here; let’s see if the experts have any additional suggestions Theoretical basis for establishing the salt consumption index of 1500 Kg/T for caustic sodaI. Industry status
1. International advanced level: 1480–1495 Kg/T
2. Domestic advanced level: 1490–1550 Kg/T
3. Domestic average level last year: 1545.5 Kg/T
II. Theoretical analysis of caustic soda salt consumption
1. Theoretical salt consumption of caustic soda, G1 = 1462.5 Kg/ton for 100% NaOH
2. Salt carried away by the caustic soda solution, G2 = 1/32% × 0.005% × 1000 = 0.16 Kg/ton (assuming a salt content of 50 PPm in the caustic soda solution)
3. Salt carried away by the waste sludge from caustic soda production, G3 = 0.3 × 1.9 × 8.5% × 1000 = 48.45 Kg/ton (assuming 0.3 m3 of waste sludge per ton of caustic soda, a specific gravity of 1.9, and a salt content of 8.5%)
4. Salt consumption due to losses (such as caustic soda used internally), G4 = 1.5% × 58.5/40 × 1000 = 21.94 Kg/ton (assuming 1.5% of caustic soda is used internally)
5. Salt consumption due to normal production losses (such as cleaning salt tanks and taking samples for analysis), G5 = 3.0 Kg/ton
6. Salt generated as a result of reactions, G6 (12–18 Kg/ton); 16 Kg/ton is assumed here (for purification reactions to remove impurity ions such as Ca2+, Mg2+, and SO42-)
Total salt consumption, G = G1 + G2 + G3 + G4 + G5 – G6 = 1520 Kg/ton for 100% NaOH
III. Areas for improvement
1. Ensure high quality of raw materials, namely crude salt and brine, in order to reduce the amount of waste sludge generated during production, as well as the amount of caustic soda needed to remove Mg2+. 2. Strengthen production operations and control to reduce the salt content in the sludge discarded and minimize process losses. In summary, there is a scientific basis for establishing the caustic soda consumption index at 1500 Kg/T. # ， ， &
The quality of the crude salt should be taken into consideration; its purity is generally between 94-96%.
Our factory’s salt consumption for diaphragm caustic is 1.652 tons. Could you provide the current average domestic salt consumption for diaphragm caustic?
I believe that salt consumption is related to the brine purification processes and caustic soda production processes of various chlor-alkali companies; without knowing these processes, there are still significant differences in salt consumption among different companies.
Floors 1 and 2: What the poster is discussing is the salt consumption per 100 units, which has no direct relation to the content of pure salt. Of course, if the level of insoluble substances is high, it increases the frequency of cleaning the salt sludge and the amount of salt sludge generated during filtration, which can have a slight impact on salt consumption. 2. The factors listed by the original poster that affect salt consumption in ion-exchange membrane caustic soda production are quite comprehensive and interesting. Here are my personal opinions: (1) Regarding point 3: From what I understand, the salt loss caused by the salt sludge generated is not as significant as claimed; this is mainly related to the content of raw salt and the control during filtration. The main components of salt sludge include magnesium hydroxide, calcium carbonate, insoluble substances (such as sediment), and barium sulfate (assuming barium-based denitration is used). If we assume that the parameters for raw salt are 95.6% purity, 0.16% calcium, 0.12% magnesium, 2.32% moisture, 0.5% sulfate ions, and 1% insoluble substances, then the amount of salt sludge generated should be less than 20% of what the original poster mentioned. Moreover, after filtration, washing, and drying, the salt content will not be as high as stated, and the specific gravity of the salt sludge is not 1.9 either. My estimate is that this amount is around 5–10 kg per ton of 100% NaOH. (2) Regarding Article 4: I’m not quite sure about the concept of alkali loss. The association’s accounting rules specify that salt consumption is calculated based on electrolytic alkali, so it has nothing to do with alkali used for internal purposes. The definition of so-called alkali for internal use is specified in the association’s accounting regulations. Currently, it consists of three components: the regeneration of electrolytic resin towers, neutralization in dechlorination towers, and magnesium removal from primary brine. The only loss occurs through the wastewater generated during regeneration (if this wastewater is not recycled); the other two components remain within the system. How much is that amount? A rough estimate is around 3–4 kg/t of 100% NaOH (this varies slightly depending on the secondary brine process). (3) Regarding Article 5: As for the salt sludge removal and analysis sampling, the analysis samples can be completely recovered; the amount of salt sludge that needs to be removed is mainly related to the insoluble substances in the raw salt. Based on personal experience, this amount is approximately 1 kg per ton of 100% NaOH. Therefore, in my opinion, the normal ion exchange membrane salt consumption level should be 1470–14801 kg/t of 100% NaOH. 3. Currently, the salt consumption figures for various units provided in the association’s documentation serve as a certain reference, but due to issues such as the measurement of raw salt, the accuracy and representativeness of the analysis data on raw salt, and the use of adulterated salt, these figures cannot be relied on entirely. From the data I’ve seen, some units have a salt consumption of just over 1,300 – do you think that’s credible? The above are merely my personal views from a technical perspective; if the original poster is setting evaluation criteria with the company, then it’s a different matter. Please point out any mistakes! This post was last edited by wlntjs on 2008-1-15 23:06.]
So, in a SRS system using nanofilm filtration, if the wastewater containing concentrated nitrate, after sulfate removal, still has a certain amount of NaCl present at a concentration of about 200 g/L, should this also be included in the salt consumption? Please discuss. If the chemical barium method is used to remove sulfate ions, there is no such consumption. The salts lost in the alkali used for personal use should also, in my opinion, not be included in the calculations.
Our salt consumption is 1525 KG/T for 100% NaOH
We are new to this business; we use imported salt from Australia, with a salt consumption of 1510 Kg/ton per 100% Na0H
Could you please tell us the specifications of the Australian salt you use upstairs?
Our company is located along the Yangtze River in Jiangsu; it was established in 2005. The plant produces 120,000 tons of ion-exchange membrane caustic soda. Initially, domestic salt was used for production, but after half a year, imported salt from Australia was adopted. Australian salt has a higher purity, produces less salt sludge, and is also slightly cheaper.
The standard theory provided in the main post is still quite accurate. Unfortunately, the salt consumption per unit in our company is truly astonishing; 1870 KG of salt is required to produce one ton of NaOH. It’s really hard to understand – over the course of a year, our costs related to salt alone are several million yuan higher than those of other chlor-alkali plants. You don’t realize it until you calculate it; it’s almost enough to drive the chairman crazy. . . Alas, in a market economy, businesses have no time to rest. . . Change, change, change.
Is there any issue with the calculation of salts carried over in the caustic soda solution? Best regards. This post was last edited by limingshuguang on 2008-1-16 at 11:49
It is understood that in 2005, **11.84 million tons of salt were consumed for caustic soda production. Based on the discussions by the above participants, there is still significant room for reducing salt consumption.
Our facility uses high-density natural circulation ion membrane electrolyzers produced by the Japanese company Chlorine Engineering to produce sodium hydroxide. We now want to calculate the amount of raw salt consumed per ton of hydroxide produced, but we’re not sure where to start. Theoretically, the brackish water coming out of the ion membrane electrolyzers can be recycled; aside from the amount of salt sludge carried along with the initial salt water, there should be no other losses. However, the actual figures we obtain are much higher than the theoretical values. Could it be that there are some losses that we haven’t taken into account? Please advise This post was last edited by shizhiyong001 on 2008-6-13 09:22.]
We also use cells from chlorine engineering; the consumption of raw salt is between 1.5 and 1.7, and the key factor is the quality of the salt.
1. Has the amount of saline returned per time been taken into account? 2. Are the various flowmeters accurate? 3. Are the saltwater concentrations accurate?
Is the calculation method also scientific and accurate?
We use electrolyzers made by Beihua Machinery for the production of soda ash via the all-solid salt process, and the consumption of raw salt remains below 1.5; we conduct our calculations based on liquid level and concentration.
During storage in salt warehouses, there is some loss, accounting for approximately 2% of the total amount
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