The development of anode protection technology has improved the level of domestic technology development, and played a positive role in promoting the development of sulfuric acid production technology. The acid separating device is to improve the service life by increasing the wall thickness of the material. In the operation process, with the increase of the service life, it will continue to be thinner, and the acid separating effect will be worse. Domestic scientific research and development units and equipment suppliers in 1988 through digestion and absorption of foreign technology in the domestic design and manufacture of industrial application of qualified equipment, through more than 10 years of popularization, anode protection concentrated sulfuric acid cooler in the domestic has been large-scale adoption, not only such as this, Through efforts also developed the anode protection of stainless steel pipe, anode protection of stainless steel acid separator, anode protection of stainless steel acid tank, has been widely used in the sulfuric acid production enterprises in the sea.

The configuration of the stainless steel pipe anode protection system is to determine the control technical indexes according to the variable parameters such as the diameter of the acid conveying pipe, the amount of acid, temperature, pressure and material, and determine the material and arrangement of the cathode and reference electrode through specific design and calculation. Ordinary stainless steel such as 18-8, 304, 304L, 316L and so on with anode protection technology, applied in concentrated sulfuric acid transport pipeline. The water tank department is designed as single or double pipe according to the process premise of each plant.

Anodic protection points acid stainless steel machine main there are two basic types of tubular and groove tube, competent points acid device is mainly composed of acid and acid tube of fall of the specifications of the acid tube number and arrangement is in accordance with the tower area computation, combining acid flow calculated each fall acid tube flow, which ensure that sulfuric acid can average assigned to each position of the tower, and convenient for field installation.

Application of anodic protection acid separator

At present, more than 60 manufacturers have adopted the anode protection pipeline in China. The single series has the largest scale of 800Kt/a device, the largest pipe diameter of DN700mm, and the longest service life has exceeded 10 years.

The anode protection system is composed of anode, cathode, reference electrode, potentiostat and connecting wire. It provides a brand - new choice for the company. There are two main reasons. First, the forging accuracy of cast iron is low and the number of holes is limited. At the same time in the installation process of the water level deviation; Third, there is a "blind area" along the tower wall.

Cast iron pipe basically depends on the wall thickness to increase the service life, and there are large pipe weight, flange connection points, acid leakage hidden points and other shortcomings; In actual production, pipe damage occurs in the form of "trashhole" erosion and brittle cracking, which easily cause safe production accidents and increase the unplanned parking time of the system.

The function of the potentiostat is directly related to the implementation of the anode protection system and the safety of the equipment. The traditional analog potentiostat circuit is mostly composed of discrete components. Because of the large number of electronic components, its stability is not high and its anti-interference ability is poor. The equipment has the advantages of long life, small footprint, high thermal efficiency, no pollution, low daily maintenance, water saving effect and so on.

With the upsizing trend of sulphuric acid plant and the progress of environmental protection consciousness, the sulphuric acid production enterprises in China are constantly adopting the reliable technology to improve the original plant, and the mature anode protection technology will be further accelerated in the application of sulphuric acid plant.

Application of anodic protection stainless steel concentrated sulfuric acid pipeline

The area of a single acid cooler has reached more than 1000m2, indicating that the design and manufacturing capacity in China can fully meet the requirements of large-scale equipment localization.

Previously, sulfuric acid production in the concentrated sulfuric acid pipe is the most commonly used cast iron pipe and a small number of lined fluorine plastic pipe. The design life of the pipeline is 8 years. At present, the special alloy groove and tube type acid separator which is resistant to concentrated sulfuric acid has been introduced into China. The acid separator can reach 22 ~ 42 points /m2, but the price is too high for domestic manufacturers to accept. Considering the inspection work, determine the acid inlet height and the height difference of the tank, to ensure that the operation will not occur overflow tank and block the acid falling pipe, the inspection and cleaning work in the tank is simple and easy, clean out the magnetic ring slag in the tank after parking, without replacing any other parts. The realization of intelligent control, only by the DCS system of the upper computer to observe the changes in data, the instrument has been close to the international level to improve the predecessors. The size of the heat exchange tube has several specifications: φ 19.05×1.65mm, φ 19.05×1.5mm, φ 16×1.5mm, etc., the heat exchange tube is generally arranged according to the triangle on the tube plate.

. Anodic protection is to form a passivation film with good corrosion resistance on the surface of stainless steel in concentrated sulfuric acid medium by applying anodic current, so that the material can be effectively protected. Although the lining of fluorine plastic pipe has excellent corrosion resistance function, but in practical application, there is the disadvantage of negative pressure resistance, when the pump is started or closed, the plastic is easy to peel off damage. The harm caused by the low efficiency of the acid separator is obvious to all. Not only can the process control index not reach the best, but also the acid foam produced will erode the downstream equipment. Domestic equipment manufacturers through years of efforts, also developed the acid point & GT; The price is moderate, and has been used in many sulfuric acid enterprises in China, the longest has been used for 7 years, can fully meet the production needs. Anodic protection of concentrated sulfuric acid pipeline technology is a new technology pioneered in China in the 1990s, leading in the world. Domestic equipment manufacturers began to test produce acid coolers in the mid-1980s, and began to use them in all kinds of acid production devices. The cathode material is basically erosion-free, the design life is more than 5 years, without inspection and replacement.

Five, the application of digital potentiostat

The anodic protection device of the anodic protection acid separator must be set in the high temperature environment of SO2 and SO3 gas in the tower, and it can be solved technically well through efforts. Anodic protection acid cooler and anodic protection pipeline products have become the preferred equipment for the dry suction section of large sulfuric acid systems in China.

A brief introduction of anode protection technology

Anodic protection is to form a passivation film with good corrosion resistance on the surface of stainless steel in concentrated sulfuric acid medium by applying anodic current, so that the material can be effectively protected. Through anodic protection,

In the 1980s, China introduced nearly 10 sets of anodic protection stainless steel tube and shell type concentrated sulfuric acid cooler, which is mainly used in the concentrated sulfuric acid cooling of dry suction section in the sulfuric acid production process.

Design of anode protection system: common anode protection devices are arranged outside the equipment, such as anode protection of concentrated sulfuric acid cooler, anode protection of stainless steel pipe, etc., the cathode, reference electrode and other anode protection of the connection of the main components are arranged outside the equipment.

The basic types of traditional acid separator are tube type acid separator and groove type hanging claw acid separator. The materials used are developed from early cast iron to low chromium cast iron and alloy cast iron. Because of the use of the advanced technology to improve the control of simple, clear, equipment driving phase of the passivation process is greatly shortened than before, reduce the acid temperature, acid concentration changes on the equipment passivation film damage. In order to reduce the entrainment of acid foam in the acid separator, the flow rate of the falling acid pipe of the groove tube should not be too high. In practical application, the anti-erosion effect is very obvious, the design service life is more than 8 years, and the leakage problem of acid transport pipeline is completely solved. With the upsizing of domestic acid production device, domestic acid coolers have been a single series of 1000Kt/a large equipment, the current application in China

The acid coolers currently used in the sea are of fixed tubeplate structure with acid running through the shell and water running through the pipe, and the heat exchange tube is fixed through the baffle plate.

Application of anodic protection shell and tube stainless steel concentrated sulfuric acid cooler

The annual erosion rate of 304L and 316L materials in concentrated sulfuric acid (92-98%) at 80℃ is only 0.08-0.01mm. Another headache for the manufacturer is inspection, because the department components need to be replaced in the tower, the working environment is harsh and the task is heavy, the annual inspection workload is large, the maintenance cost is large, and the inspection time is long.

At present, more than 3000 sets of acid coolers are used in China. With the large-scale use of the equipment, the design and manufacturing technology of acid coolers in China has become mature, and the users have accumulated a lot of experience in the use. The longest use time of domestic acid coolers has exceeded 10 years. The acid point is general. 20 points /m2, the acid separation of the whole tower plane is not ideal. At present, microcomputer control technology has been adopted to realize the digital processing of potential, current and voltage signals to the remote terminal, and can be easily connected with various DCS systems.

Equipment manufacturers at home and abroad to this hub technology development has never stopped.

Anode protective shell stainless steel concentrated sulphuric acid cooler (hereinafter referred to as acid cooler) was first introduced from abroad in the early 1980s, used for the cooling of concentrated sulphuric acid in dry suction section of all kinds of acid production equipment, the main foreign suppliers are Canada Kamico company and the United States Monsanto Company. The material of heat exchange tube is 316L, the material of shell, tube plate and baffle plate is different, which is 304, 304L, 316L and so on. The application in recent 10 years shows that it is feasible to adopt the common stainless steel pipe with anode protection technology, and it is practical and economical.