CN111099191A

CN111099191A - Corrosion-resistant protection method for ship metal composite plate container

Info

Publication number: CN111099191A
Application number: CN201911224495.5A
Authority: CN
Inventors: 段鹏波
Original assignee: Sunrui Marine Environment Engineering Co ltd
Current assignee: Sunrui Marine Environment Engineering Co ltd; Qingdao Sunrui Marine Environment Engineering Co Ltd
Priority date: 2019-12-03
Filing date: 2019-12-03
Publication date: 2020-05-05
Anticipated expiration: 2039-12-03
Also published as: CN111099191B

Abstract

An anticorrosion protection method for a ship metal composite plate container comprises the steps of welding external strengthening metal layers at the butt joint of composite plates forming the container with each other, reserving a gap between the butt joint edges of the internal corrosion-resistant metal layers at the butt joint, and welding a cover plate between the butt joint edges of the two internal corrosion-resistant metal layers to seal the gap to form an anticorrosion cavity; an air inlet, an air outlet and a residual liquid discharge outlet which are communicated with the outside are arranged on the external strengthening metal layer outside the anticorrosive cavity; protective gas with positive pressure relative to the internal pressure of the container is added into the anticorrosion cavity through the gas inlet, and the pressure of the protective gas is maintained; the inside hydrops situation of raffinate discharge port inspection is opened regularly, prevents inside transition hydrops. The invention has the advantages that: the protective gas of positive pressure is utilized to prevent corrosive media from entering the welding seams of the composite plates, so that the welding positions are effectively prevented from being corroded, the leakage of the container is effectively avoided, the service life of the container is prolonged, and the equipment maintenance cost is saved.

Description

Corrosion-resistant protection method for ship metal composite plate container

Technical Field

The invention relates to an anti-corrosion protection method for a ship metal composite plate container, which is mainly used for anti-corrosion protection of a container which is made of a metal composite plate through welding and used for loading corrosive media to a welding position.

Background

With the development of the global economy, the international trade and the shipping industry are rapidly developed, and the environmental pollution caused by the rapid increase of the exhaust emission of marine diesel engines is becoming serious, wherein the harm to the environment and human beings caused by the emission of nitrogen oxides (NOx) and sulfur oxides (SOx) is most direct. In order to reduce the atmospheric pollution caused by the exhaust gas emission of ships, the International Maritime Organization (IMO) and the Maritime Environmental Protection Committee (MEPC) have strictly limited the emission standards of NOx and SOx from marine diesel engines. In order to deal with the characteristics of high temperature and high corrosivity in the process of desulfurization and denitration, a special reaction vessel becomes the core equipment of the gas treatment technology.

The metal composite plate container can be used for loading corrosive media, and the common structural form is that the inner special corrosion-resistant metal and the outer cheap strengthening metal are adopted. The composite plate container for the ship is generally built for storing high-temperature and corrosive hot and wet flue gas of the ship, the working environment is severe, and long-term manual maintenance cannot be performed. After the damage occurs, the area of the damage at the initial stage is small, the medium density is low, the pressure is small, and the color is almost colorless, so that the real-time monitoring at the initial stage of the damage is difficult. When the damage is developed to a certain stage and the damage source is found by manual detection, the damaged corrosion area often exceeds the original welding protection area and even corrodes to an external strengthening material. Such corrosion can only be repaired by cutting the vessel again and welding, which is labor and time consuming. And can lead to flue gas treatment violation during the operation of the ship, and cause threat. In addition, the physical characteristics of different materials of the composite board are different, so that the local stress concentration cannot be avoided in the forming process. And in the composite board remolding (such as reel, welding etc.) in-process, can take place the deformation of different degree between the different materials of composite board, fashioned container can not reach the target of material evenly distributed, has resulted in the production of corrosion-resistant weak area (stress concentration district, even dew point). Such corrosion-resistant weak areas often occur at the weld site, resulting in direct damage to the structure or residual stresses that accelerate structural failure during later use.

At present, the anticorrosion protection technology for metal composite plates only stays in weld joint preparation protection and repair after damage, for example, the invention name of a welding protection method for a T-shaped joint of a titanium plate or a titanium composite plate (CN109277717A) discloses the protection of weld joints by using special coating liquid; the method for repairing the titanium composite plate by using the furnace heating mode (CN107164714A) cannot effectively control the structural damage speed and protect the composite plate structure. The lack of an anti-corrosion means in the use process of the composite plate container seriously reduces the service life of the composite plate.

Disclosure of Invention

The invention aims to provide an anti-corrosion protection method for a ship metal composite plate container, which aims to solve the problem that the service life is shortened due to the fact that a welding seam of the existing composite plate container is easy to corrode.

The technical scheme of the invention is as follows: an anticorrosion protection method for a ship metal composite plate container comprises the steps that a container is manufactured by butt welding of an internal corrosion-resistant metal layer and an external reinforcing metal layer composite plate, and is characterized in that the external reinforcing metal layers at the butt joint of the composite plates are mutually welded, a gap is reserved between the butt joint edges of the internal corrosion-resistant metal layers at the butt joint, and a cover plate is welded between the butt joint edges of the two internal corrosion-resistant metal layers to seal the gap to form an anticorrosion cavity; an air inlet, an air outlet and a residual liquid discharge outlet which are communicated with the outside are arranged on the external strengthening metal layer outside the anticorrosive cavity; protective gas with positive pressure relative to the internal pressure of the container is added into the anticorrosion cavity through the gas inlet, and the pressure of the protective gas is maintained; the inside hydrops situation of raffinate discharge port inspection is opened regularly, prevents inside transition hydrops.

The invention has the advantages that: the protective gas of positive pressure is utilized to prevent corrosive media from entering the welding seams of the composite plates, so that the welding positions are effectively prevented from being corroded, the leakage of the container is effectively avoided, the service life of the container is prolonged, and the equipment maintenance cost is saved. Meanwhile, a discharge port inspection scheme which is convenient for personnel to inspect working conditions regularly is provided, and the working difficulty of personnel inspection leakage is simplified.

Drawings

FIG. 1 is a flow chart of an embodiment of the present invention;

FIG. 2 is a cross-sectional structural cross-sectional view of a welded composite plate container of the present invention

FIG. 3 is an enlarged view at A in FIG. 2;

fig. 4 is a left side view of fig. 3.

Detailed Description

Referring to fig. 1-4, the corrosion protection method of a ship metal composite plate container of the present invention includes a container manufactured by butt welding an internal corrosion-resistant metal layer 1 and an external reinforcing metal layer 2, and is characterized in that the external reinforcing metal layers 2 at the butt joint of the composite plates are welded to each other (welded joint 4), a gap is left between the butt joint edges of the internal corrosion-resistant metal layers 1 at the butt joint, and a cover plate 3 is welded between the butt joint edges of the two internal corrosion-resistant metal layers 1 to seal the gap to form a corrosion-resistant cavity 5; an air inlet 6, an air outlet 7 and a residual liquid discharge outlet 8 (which are respectively provided with interfaces, not shown) which are communicated with the outside are arranged on the external strengthening metal layer 2 outside the anticorrosion cavity 5; protective gas (compressed air or inert gas) with positive pressure relative to the pressure inside the container (stored medium) is added into the anticorrosion cavity 5 through the air inlet 6, and the pressure of the protective gas is maintained after the purification and drying treatment is carried out by a clean dryer. Can regularly open 8 inside hydrops situations of raffinate discharge port through valve 9, prevent inside transition hydrops. The accumulated liquid can be detected by a sensor (such as a PH meter) to judge whether the corrosion medium permeates.

Through the technical scheme, the invention can test the following functions:

a) active positive pressure protection: the method is different from the technical standpoints of corrosion prevention (such as welding protection, acid pickling treatment and the like) before use and repair after damage in the prior art, and provides a method for carrying out active positive pressure protection on the composite board in the process of using working conditions. Through specific design, the pressure of the protective gas at the gas inlet 6 is higher than that at the gas outlet 7, and the pressure in the inner container in the protective area (the anticorrosion cavity 5) is relatively positive, so that corrosive media are prevented from permeating into the protective area.

b) Active monitoring: the corrosion prevention cavity 5 is provided with a residual liquid discharge port 8 (shown in figures 1 and 4) which is connected to a sensor for detecting whether the characteristics of residual liquid (such as PH value or other harmful components such as chloride ion content) exceed the working range, and if so, an active trigger signal is exceeded to inform maintenance personnel. The manpower maintenance difficulty is reduced, and the leakage accident is protected in time.

The specific implementation of the invention is seen in the following table:

1. welding of composite sheets

2. Setting interface

3. Ventilation protection

Claims

1. An anticorrosion protection method for a ship metal composite plate container comprises the steps that a container is manufactured by butt welding of an internal corrosion-resistant metal layer and an external reinforcing metal layer composite plate, and is characterized in that the external reinforcing metal layers at the butt joint of the composite plates are mutually welded, a gap is reserved between the butt joint edges of the internal corrosion-resistant metal layers at the butt joint, and a cover plate is welded between the butt joint edges of the two internal corrosion-resistant metal layers to seal the gap to form an anticorrosion cavity; an air inlet, an air outlet and a residual liquid discharge outlet which are communicated with the outside are arranged on the external strengthening metal layer outside the anticorrosive cavity; protective gas with positive pressure relative to the internal pressure of the container is added into the anticorrosion cavity through the gas inlet, and the pressure of the protective gas is maintained; the inside hydrops situation of raffinate discharge port inspection is opened regularly, prevents inside transition hydrops.

2. The corrosion protection method for the ship metal composite plate container according to claim 1, wherein the accumulated liquid is detected by a sensor to judge whether the corrosion medium infiltration condition occurs.

3. The method for corrosion protection of a marine metal composite plate container according to claim 1, wherein the protective gas is air or an inert gas.