Just how to avoid internal corrosion of natural gas pipeline ？
For natural gas pipe, inner deterioration is the electrochemical reaction of recurring water and acid gas in the pipe similar to galvanic cell as well as the chemical reactions that destroy the metal lattice. Both of these responses trigger the pipe wall to loosen up, diminish and pierce, which can no more withstand the pressure of gas in the pipeline. In functional application, a kind of layer can not be great security, or can't satisfy the demand such as anti-corrosion, weather condition resistance, great appearance, and therefore most numerous covering on steel surface layer work together to create an entire system, consisting of primer layer, the middle layer, paint, covering one or several times each layer specifically as called for, as well as there is only solitary layer such as powder finishes can satisfy the different demands at the exact same time.
The anti-corrosion covering of gas pipeline need to have the complying with buildings: effective electric and water insulation; Not restricted by layer techniques; Good attachment to pipeline surface; WLDSTEEL.COM Resistant to damage throughout installation, storage space and transport; Resistance to chemical tool damages; Easy to fix; Long service; Environmentally pleasant and also non-toxic. Today, the anti-corrosion finishings for cross country transport pipelines mostly consist of coal tar paint, 2LPE, 3LPE, merged epoxy powder (FBE), as well as double-layer merged epoxy powder (FBE double-layer) covering.
Coal tar enamel.
Coal tar paint layer is the very early secondhand coating, it's defined by good insulation performance, low tide absorption, resistance to microbial rust and also plant origin penetration, long life span and also affordable price. Nevertheless, its mechanical toughness is reduced as well as has a small appropriate temperature variety, it might run away harmful gases and needs strict smoke therapy. Recently, it has actually been gradually replaced by various other covering layers as a result of the limitation of environmental protection.
2LPE.
2LPE has good insulation efficiency, low water absorption, high mechanical toughness, tough wear resistance, acid, antacids, salt as well as bacterial deterioration, temperature level change resistance.
However, there are likewise disadvantages: very easy aging, inadequate attachment with the steel tube surface, bad anti-cathodic stripping performance. Electrostatic protecting of PE layer is not for exterior current cathodic security.
3LPE.
The three layers of PE anti-corrosion layer integrate the benefits of high density polyethylene and integrated epoxy powder. The epoxy powder is strongly combined with the surface area of the steel pipe, and also the high thickness polyethylene is immune to mechanical damage. The glue layer between the two layers makes the three form a composite structure of molecular bond, which understands the good combination of deterioration resistance and mechanical residential or commercial properties. It is the front runner for large-scale gas transport pipeline design.
Blend bonded epoxy powder (FBE).
The PBE layer has strong bonding with the surface area of the steel pipe, excellent insulation efficiency, high mechanical strength, temperature level adjustment resistance as well as chemical deterioration resistance, and also can be utilized in a variety of extreme environments. The major downside is bad ultraviolet resistance and also the slim overburden layer (0.35 ~ 0.50 mm). The double-layer FBE is similar to 3PE, with good compatibility, smooth surface area of the covering layer, which can avoid cathodic securing.
So, exactly how does the finishing secure the internal wall of the gas pipe? We already understand that metal deterioration is because of the action of the ecological medium on the metal surface to create electrochemical response or chemical reaction, the impact of the layer on the pipeline is attained by preventing the above responses:.
( 1) Shielding: Many finishes on acid, alkali, salt and also various other harsh media reveal chemical inertia, and the high dielectric constant to stop the formation of deterioration circuit, so the metal surface area covering to the metal surface area and also the environment seclusion as well as protecting the harsh medium. It has to be explained that the polymer finish is breathable and carefully pertaining to its framework.
( 2) Passivation slow launch: With the help of antirust pigment in the coating as well as the steel surface response, make it passivation or generate protective substances; In addition, lots of oils can also serve as organic rust preventions by generating deterioration products under the catalytic action of metal soaps.
( 3) Electrochemical protection: The covering possibility is lower than iron metal filler (such as zinc) will sacrifice the cathodic defense of the anode, and also the atmospheric corrosion products of zinc antacids zinc carbonate is relatively steady, can be shut, plug the last gap.
So just how to avoid the corrosion of the inner wall of the natural gas pipeline? We can prevent by doing this: firstly, the gas drawn out from the ground undergoes a collection of procedures such as desulphurization and dehydration, prior to it gets in the long-distance pipe. Second of all, the efficient inner finish of the pipe can decrease rust, gas transmission resistance and also cleansing time.
