In a boiling furnace for industrial sulfuric acid, why is a strong air flow introduced to the bottom

Increase the reaction contact area, increase the reaction rate, and increase the efficiency.

The principle is what is the industrial production of sulfuric acid, and the gas from the boiling furnace should be purified.

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Answer D analysis: The impurities and mineral dust in the furnace gas will poison the catalyst, and the water vapor will also have a negative impact on equipment and production, so the furnace gas must be purified

In the process of acid production from sulfuric acid, boiler steam-water azeotropic and steam-water co-rise are two different concepts, first of all, figure out what the phenomenon is.

Steam-water azeotropic: When the boiler steam carries a part of the water to the steam system, it will cause the on-site water trap to operate continuously and waste energy, and the process heating is not easy or the liquid level of the furnace body fluctuates too quickly, resulting in the boiler flameout.

Steam-water co-rise refers to the phenomenon that the evaporation surface of the boiler or the water level gauge rises together, producing a large amount of foam and fluctuating up and down. At this time, a large amount of water is carried in the steam, and water shock occurs in severe cases.

The reason for the co-rise of soda and water: the quality of the pot water is too poor, the suspended solids or salt content is large, and a lot of foam is produced on the surface of the pot water, and when the foam bursts, the steam in the bubble escapes and takes away the splashed water; Severe overload operation, aggravation of water surface vaporization causes water surface fluctuations or steam carrying water; insufficient surface discharge; Open the main steam valve too quickly when the furnace is combined.

When the steam-water co-rise is generated, the combustion should be weakened, the load should be reduced, and the main steam valve should be closed; Fully open continuous blowdown valve, properly open regular blowdown valve; increase water supply to improve water quality; Open the traps of the superheater and steam piping; Increase the number of analyses of the pot water, and resume operation when the water quality improves and the water level is clear.

The main measures to prevent the co-production of steam and water are: strengthening the treatment, analysis and monitoring of boiler feed water; Pay attention to the amount of sewage discharged according to the quality of the water; Boilers above medium pressure should adopt continuous blowdown; When the load increases, pay attention to the pumping speed not to be too fast to ensure that the water level is in a normal state; When merging the furnace, pay attention to the speed of opening the main steam valve not too fast.

a. The furnace gas coming out of the boiling furnace needs to be purified because the impurity gas contained in it will poison the catalyst in the contact chamber in the next step, and the catalyst poisoning will affect the progress of the reaction, so A is wrong;

B, pyrite needs to be crushed before combustion, because the large pyrite can not be fully burned in the air, the contact area between pyrite and oxygen after crushing increases, which is conducive to its full combustion, and the large pyrite is not fully burned in the air, which will cause a waste of resources, and it is not easy to feed, so B is wrong;

c. Absorb SO3 with water, release heat, form a large amount of acid mist, affect the absorption of SO3, so the concentrated sulfuric acid absorption is used to reduce the acid mist, so C is correct;

d. When SO2 is oxidized to SO3, a catalyst needs to be used, which only accelerates the reaction rate, does not affect the equilibrium movement, and cannot improve the SO2 conversion rate, so D is wrong;

Therefore, C

C Correct Answer: C

a Incorrect, the furnace gas coming out of the boiling furnace needs to be purified, because the impurities in the furnace gas can poison the catalyst;

b Incorrect, pyrite needs to be crushed before combustion, so that it can be fully combusted;

c Source next to the correct hail with oak, SO3

The purpose of the concentrated sulfuric acid absorption is to prevent the formation of acid mist so that the SO3 is completely absorbed with the water and SO3

The reaction is exothermic;

d Incorrect, SO2

Oxidation to SO3

Catalysts are needed to increase SO2

, but does not increase the conversion rate of the reaction.

Answer: The purpose of removing mineral dust and washing is to prevent catalyst poisoning, and the purpose of drying is to prevent the corrosion of water and the formation of acid by high combustion vapor and sulfur dioxide on the equipment and the adverse effect of catalytic oxidation in the contact chamber.