Method and acid distributor for uniformly distributing sulfuric acid

Abstract

The invention discloses a method and an acid distributor for uniformly distributing sulfuric acid. The method for uniformly distributing the sulfuric acid is implemented by the aid of a pre-distribution cavity. A main acid distribution component which is communicated with the pre-distribution cavity is arranged on the lower side of the pre-distribution cavity, and a plurality of acid distribution branch pipes with equal heights are arranged on the main acid distribution component; the pre-distribution cavity, a cavity of the main acid distribution component and cavities of the acid distribution branch pipes are connected with one another to form a closed acid liquor channel, only acid liquor inlets are only formed in the pre-distribution cavity, and acid liquor outlets are uniformly formed in the lower portions of the acid distribution branch pipes; the circulation cross section of the pre-distribution cavity, the total circulation cross section of the main acid distribution component and the total circulation cross section of the acid distribution branch pipes are larger than the section of the acid liquor inlets. The method and the acid distributor have the advantages that acid liquor can be uniformly distributed by the aid of the method and the acid distributor; the flow rate of the acid liquor is controlled, the acid liquor in the pre-distribution cavity, the main acid distribution component and the acid distribution branch pipes is in un-full states, partial air in acid liquor unfilled spaces is exhausted, and accordingly stable flow of acid liquor discharged from the various acid liquor outlets can be uniformly distributed.

Description

technical field [0001] The invention relates to the technical field of acid making equipment, in particular to a method for uniformly distributing sulfuric acid and an acid divider. Background technique [0002] The acid separator is an important part of the dry absorption tower in the concentrated sulfuric acid production equipment. The sulfuric acid needs to go through multi-stage diversion in the equipment, and finally flows out through the acid separation point on the end branch pipe. The flow conditions of the acid liquid branch and the final terminal branch 1. The distribution of the pressure head will affect the steady flow of the entire device. It is not only required that the equipment has corrosion resistance to acid flow erosion under harsh working conditions, but also has the ability to effectively classify under certain acid flow conditions. And uniform distribution of multi-stage steady flow. The problems existing in the production and use of various acid dist...

AI Technical Summary

Problems solved by technology

[0003] 1. A number of acid outlet holes are installed at the end of the acid distributor equipment. No matter in the past, the acid distributor is designed or has been put into use. The acid head at the acid outlet hole is unstable and often changes, and some The distribution of the acid pressure head and acid output of the side by side acid outlet holes is very uneven, with large deviations

The traditional tubular acid separation has a small distribution density of acid separation points. It is a positive pressure flow or an upward spray flow or a natural flow. There is no clear pre-separation system. In actual use, the acid liquid distribution in the tower is uneven and the outlet momentum Larger, etc., have long been unresolved

[0004] 2. In the design and manufacture of the traditional acid distributor, no effective and systematic special research has been carried out. The main performance is that it is linearly distributed, the main and branch pipes of the acid distributor are mixed, and the structural composition is single, and the specific components of different components are not considered. Working condition efficiency, there is no innovative flow diversion efficiency system, slow flow components, point equalization and blind spot resolution, etc., and there is no deep innovative application of negative pressure flow regulation and steady flow. These many defects directly lead to acid hydraulic pressure in the acid distributor. The difference in force is large, forming turbulent flow and backflow in the tank and cavity of ordinary tablets, which makes the flow distribution of each acid point extremely poor and the momentum is large to bring out acid mist

In the overcurrent system, the flow error between the center area and the side area of ​​the acid flow is too large and uncontrollable, which also leads to the long side area or flow section of the component. After long-term use, there will be weak flow or blocked holes, which is serious. Affect the normal production of the system

[0005] 3. During the use of the trough-type acid distributor, when the orifice plate is ground and reamed and gradually fails, or the amount of acid supplied is too large and the current is unstable, the momentum will cause the acid in the tank to roll, resulting in serious disturbances. The small overflow pipe is partially full or full, and even the acid liquid overflows from the tank

The small overflow pipe protrudes, making it difficult for the acid point to obtain an equal distribution of the flow rate, and there are many acid dead ends, so that the height of the tower body and the packing cannot be effectively reduced

[0006] 4. The trough-tube acid distributor accounts for more than 50% of the cross-sectional area of ​​the tower, and the bottom width of the acid tank is extremely wide to form a vortex, which makes the gas concentrate and accelerate to the side of the tank to bring out acid mist, corrode the pipeline, and shorten the life of the equipment

Due to the use of overflow acid separation, all acid separation overflow ports are required to be on the same plane, which puts high requirements on the production and installation of equipment. If the error is too large, it will cause more uneven distribution of acid flow in overflow small pipes and more shut-off pipes, these conditions will increase the acid mist or aggravate the friction corrosion of the overflow small pipe

In smelting and sulfuric acid enterprises, the small overflow pipes used for diversion are corroded and scrapped to varying degrees after being used for about 2 years, causing damage to the equipment environment before series investment and shutdown

The diversion at the overflow inlet is slow (0.1m / s), which is easy to accumulate acid scale, block holes and increase the flow of small pipes

If there are many impurities in the flue gas or the precipitation and filtration of the circulation tank is poor, the impurities will enter the acid tank and deposit. If they are not cleaned in time, the buffer efficiency in the tank will be reduced or the cleaning difficulty will increase, and even the holes will be blocked.

The acid liquid of the tank tube type acid distributor is directly flushed into the acid tank through the acid inlet pipe. This method makes the kinetic energy of the acid liquid in the acid distribution tank larger, and the liquid level gap between the tanks increases, that is, an overall acid distribution tank is formed. Point flow is more uneven

[0007] 5. The filler (porcelain ring or silicon whole) in the dry suction tower will be damaged during filling or use, so that the acid separator at the bottom of the tank or the overflow of the liquid surface will be broken. The acid liquid is deposited on the small nozzle of the diversion pipe or in the tank or floats on the diversion port, which increases the uneven diversion of the acid liquid, and even some blockages cause liquid flooding, which increases the damage of the ceramic ring and affects the diversion effect

In addition, in acid production, due to various flue gas purity reasons, acid sludge will be generated, which will be deposited in the acid tank or form a blockage or directly affect the effective wetted area and mass transfer efficiency of the filler.

[0008] 6. Due to the superposition of the initial acid flow distribution error, the flow of the acid separation overflow small pipe is uneven, and the tower body cannot be fully utilized, so it is necessary to maintain the traditional tower height, which increases equipment and construction investment, and the acid pump needs to put the acid Pumping to a higher tower position also increases the power consumption of the equipment and the long-term operating cost

In addition, the backflow problem at the end of the acid balance leads to the distribution of the acid pressure head being too concentrated. The unequal pressure head of each acid hole increases the difference in the amount of acid output from the acid hole, making it difficult for the acid flow to form a stable and uniform flow in the device. flow distribution, while also speeding up the balance of the damaged device

Aiming at this kind of problem, the material improvement technology of the acid distributor with the patent application number CN201320180206.8 uses stainless steel as the pipe material, and relevant reinforcement is carried out at the pipe connection to facilitate installation and reduce equipment loss, but it does not take into account the impact of high-concentration sulfuric acid on the pipeline. The scouring friction corrosion and chemical reaction corrosion of a certain element, but no improvement has been made for the turbulent flow inside the pipeline, the small distribution of points, and the rapid expansion of the outlet of the acid point, making the flow more uneven.

The high frequency of replacement leads to high production stop costs, and the loss is only alleviated to a certain extent, so it is still an extremely imperfect technology

Application number CN201020278650.X is the technology for improving the structure of the acid outlet at the end of the tubular acid distributor, which solves the problem of uneven acid distribution by setting components with a certain structure and can adjust the radial direction, but ignores the problem of the liquid intake of the acid distributor. Stability, the problem of uniform outlet flow at the end is required, and the main factor affecting the uneven acid flow in the tubular acid distributor is the flow of acid flow. This problem has not been solved, but the maximum acid output at the outlet has been changed, and the effect is not obvious. , and this operation will cause the structure to be easily worn and worn, and there will be more active components, forming more blind spots where the points are not in place, and corrosion and flaring will often occur, resulting in increased shunt errors

These lead to faster wear and tear on equipment and higher maintenance costs

Other related improvement measures include changing the shape of the lumen. For example, the patent application number is CN200920193683.1, which uses rectangular tubes. This technology has the advantage of convenient processing, but it does not pass through the fluid The scientific calculation of mechanics occupies a large cross-sectional area of ​​the tower. The use of rectangular tubes forms a linear distribution. The distribution of point flow is uneven and the acid liquid at the outlet is easy to disperse and form fog. Large and small tubes at right angles will produce larger The turbulence and turbulence of the flow, and the flow rate at the right angle does not decrease, which increases the inhomogeneity of the acid distribution to a certain extent

Did not play a role in reducing acid foam and reducing emissions

[0011] 2. The tank-type acid distributor adopts stainless steel buffer baffle (slow flow plate) in the tank during use and at the same time uses a small overflow tube to divert the concentrated flow acid from the tank to the outside. This kind of protective film or some use of anodic protection to ensure the normal use of its materials are not suitable

The reason is that during the operation of the device, the concentration of acid flow is too high, and the round hole at the baffle plate forms a torrent, which accelerates the friction and corrosion. Corrosion and weightlessness cause empty pipes or their own empty pipes. The protective film or electrochemical protection of the material itself cannot achieve good results. The protection of some positions actually accelerates the loss of materials. In addition, certain elements in the material will directly follow the The action of concentrated acid has accelerated the crystal tip corrosion of the material itself

In addition, in the past, the slow flow baffle needs to be replaced continuously during the operation of the trough-type acid separator, which is extremely unfavorable for the continuous production of the equipment

Because the baffle plate is in the acid tank of the trough-type acid separator, it is located in a higher tower position in the tower body. In addition to the need to stop production, the disassembly and installation process is particularly complicated, which will delay a lot of time and greatly increase manpower and equipment. The maintenance cost is also not conducive to the stable production of the system

The patent application number is CN201520784718.4, which is used for the technical improvement of the pipe tank type acid distributor. Although this technology slightly improves the uniformity of the tank type acid distributor through structural optimization to a certain extent, it is still a small overflow tube that is subject to weight loss erosion and abrasion. It is unavoidable to avoid early scrapping caused by the friction corrosion of concentrated acid and the chemical corrosion of Mo element contained in stainless steel and concentrated sulfuric acid, and the structure of the small pipe is diversified, the distribution of points is poor, and the blind area is large, etc., and the overflow small pipe is at different heights , different bending angles and lengths of the self-shunting uneven defect is obvious

Furthermore, it is impossible to solve the problem of uneven flow on the acid liquid surface with high and low pressure fluctuations and the overflow in the tank with wall end effect.

[0012] 3. Although the trough-type acid distributor adopts small overflow pipes of different lengths to distribute acid around the tank, it is hoped that the amount of acid liquid at each overflow acid outlet is consistent with the pressure head, but due to the time of the acid liquid flowing down from the main acid inlet pipe They are all impacting the acid liquid in the tank, so that there are still very obvious acid flow fluctuations in the acid tank, and in order to ensure that the outlet pressure head at the end is as small as possible, the outlet of the overflow small pipe tank is generally set near the tank page, so that each The overflow at the outlet is always affected by the backflow effect of the tank wall, the flow and pressure head are fluctuating and unstable, and the pressure head has not been effectively reduced, and the acid flow continuously appears in a concentrated area, making the distribution of each overflow port uneven And the acid froth in the tank also leads to the inability of the acid distribution equipment to be fully utilized

The trough-type acid distributor with the patent application number CN200920037702.1 adopts electrochemical anode protection, which is intended to solve the problem of rapid equipment loss, but this protection mechanism is only applicable to the static corrosion of sulfuric acid. The empty pipes formed by the acid weight loss and the empty pipes that will not be full themselves have no good protection effect, and the inherent uneven flow rate and point uneven distribution (blind area) of the trough-type acid distribution have not been fundamentally resolved. It also increases the energy consumption and maintenance cost of the equipment, and even aggravates the corrosion of materials

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