1、（Tianjin Oriental Wise Energy Sci-Tech Co., Ltd. Beijing 2010）Abstract: Development of inhibitor was overviewed from the aspects of inhibiting group and molecular structure. The inhibition mechanisms of electrochemistry and physical chemistry were demonstrated, and the factors affecting the inhibiti
2、on effect were analyzed by molecular structure theory. Finally the application and developing directions of inhibitor were discussed.Key words:corrosion mechanism; inhibitor; inhibiting group; inhibition mechanism; effect factorsOil industry in Chinas national economy plays a important position. The
3、 corrosion of Oil exploration and processing process equipment directly affect the enterprises safety production and operating cycle. The accident causes by corrosion of equipment lead to shut down device, making the petrochemical enterprise suffered huge losses in economical. Equipment anti-corrosi
4、on work has become important in the production of oil processing work. This article in view of the above situation, to oil extraction, transportation and processing equipment anti-corrosion do related research.Since most of the oil recovery liquid moisture content more than 90%, scaling tubing is se
5、rious. Together with the water failed to comprehensive the standard, infuse equipment, oil well pipeline and ground gathering and transportation pipeline have seriously corrosion phenomenon, even cause perforation and scrap, seriously influenced oilfield normal production and loss enormous economic
6、. At present, the injection corrosion inhibitor method is a common oilfield antisepsis measures. But it exist the following problems: a）. The corrosion inhibitors filling need equipment such as dosing pump not convenient, large workload; b）. Corrosion inhibitors easy adhere to walls, large consumpti
7、on. c）. The intermittent infuse dosing uneven, and effectively protect time is short. In addition, some large water produce well, high water well, remote well and add a packer of the well,the used of corrosion inhibitors also exist some inconvenience.Oil pipeline corrosion is mainly caused by the se
8、dimentary water of crude oil, the comprehensive moisture content of crude oil rise to 80% -90% in China, the quality characteristics increasingly complex, and sometimes even contain high concentrations of CO2, H2S, and cause pipeline corrosion problems worse. Therefore, add efficient corrosion inhib
9、itors can reduce corrosion and loss. At present, corrosion inhibitor technology is develop toward low-toxic environmental protection plant type direction., The corrosion mechanism of crude oil equipmentA. crude oil impuritiesCrude oil equipment the main contact is oil, water, air, gas, acid gas, etc
10、. The main constituent is all sorts of hydrocarbon alkyl, cycloparaffin and aromatics, they are not corrode metal equipment, but impurities contains such as mineral, sulfide, nitrides, organic acids, oxygen, carbon dioxide and water, these little content of great harm. Because in the machining proce
11、ss some itself is corrosive medium, and some other although itself no corrosive but in the machining process become corrosive medium. Besides during the oil extraction and processing inject water, hydrogen and acid-base chemicals also form the corrosive medium, and the corrosion medium during proces
12、sing in the high-temperature and high-pressure environment will happen strong corrosion reactionsand with metal materials, thus causing production equipment corrode.B. sulfur corrosionThe sulphur of crude oil including the elemental sulfur, hydrogen sulphide, mercaptan, sulphuring ether, vulcanizati
13、on, chlorimiphenin compounds and molecular large structure complex sulfur compounds. Generally divide the sulphur to un-active sulphur and the active that existed in crude oil. The element sulphur, hydrogen sulfide and low molecular mercaptan etc can directly work with the metal cause equipment corr
14、osion called active sulphur; The rest was un-active sulphur. Research found that the active sulphur produced corrosion is restrict by environmental factors, especially the influence of the temperature. In sulfur crude oil processing process, because the un-active sulphur ceaseless transform to activ
15、e sulphur, so sulfur corrosion exists not only in one processing, also exist in the secondary processing devices, even extended to downstream chemical device. Can say that sulfur corrosion throughout the whole process of refining. There have many classification method of sulfur corrosion, according
16、to the influence of temperature on sulfur corrosion can divided it into two types: and low temperature parts of the corrosion corrosion.Low temperature parts corrosion: Usually called the part below 120 of liquid water low temperature area. These parts of the corrosion also called wet hydrogen sulfi
17、de or hydrogen sulfide solution state corrosion. With the rise of temperature, water has been completely vaporization, without liquid water conditions hydrogen sulphide and hydrogen chloride do not produce significant corrosion even though the temperature high to 240 . therefore, to respond the high
18、 temperature parts sometimes call the below to 240 low-temperature parts.High temperature parts of the corrosion:mainly refers to the corrosion occurs in refining contain sulfur or high crude in often when the pressure-relief devices more than 240 high temperature heavy oil place and catalytic crack
19、ing, delayed coking, thermal cracking devices and corresponding pipelines, etc, parts of the corrosion.C. Environment of the refining device corrode The corrosiveis environment of oil extraction and processing is more complex, mainly depends of the crude oil properties, processing products, temperat
20、ure, pressure, processing technology , equipment parts and other factors. Usually can classity the corrosive environment by environmental temperature and corrosive medium, and this classification methods classified it into low-temperature corrosive environment and high-temperature. The low temperatu
21、re corrosive environment in refinery, usually mean temperature below the 230 and have liquid water existed place, while the high-temperature corrosive environment means in 240 500 parts., Factors affect of oil corrosion Oil acid are the acidity material in oil, including fatty acid, the naphthenic a
22、cid, aromatic acid and other substances such as phenols, mercaptan, hydrogen sulfide, inorganic acid etc. , account of them about 1-2 % of crude oil. The naphthenic acid in normally 90 % or so content in the oil acid , which is general of a kind carboxylic acid mixture of complex and wide range of b
23、oiling. In the metal surface appear characteristics pit or in fluid flow region happen impact corrosion is typical of naphthenic acid corrosion. It with amazing corrosion rate damage the the alloy material usually used inhibit sulfide corrosion. In many cases, even high alloy materials （such as 12Cr
24、, austenitic stainless steel 316 and 317） also appeared corrosion phenomena. Main influence factors of naphthenic acid corrosion are the following:A. acid valuethe total acid is an important parameters of The crude oil to measure value is the naphthenic acid corrosion. The first study consider that
25、the total acid value reach to 0.5 mgKOH of one gram oil, can cause the naphthenic acid corrosion. Numerous experiments show that, in certain temperature range the naphthenic acid content and the acid value have no definite relationship , that also explain there no definite relationship between corro
26、sion rate acid value. Because the process of oil distillation, acid components coexist with the same boiling point oil, so only the acid value of distillate oil truly decided the naphthenic acid corrosion rate.B. SulfideS is the most content elements in oil after the C, H. It exists in the form of e
27、lemental sulfur, hydrogen sulphide, mercaptan, sulfide, polysulfide. Total sulfur generally uses ASTMD4294 method to determine by the X-ray fluorescence spectrometer, but the heavy metal and halide have distractions.As is known to all, sulfur content upto 0. 2 %, will be cause the carbon steel and t
28、he low alloy steel in the range of 230-455 . When sulfur corrosion exist only can according the corrosion corrosionfactor prediction of corrosion, the distillate oil sulfur content and the results of specific analysis sulfide can better predict oil corrosion, hydrogen sulfide precipitation experimen
29、t also can predict oil corrosion. In early 1953, have found that the hydrogen sulphide precipitation can well correlate with the corrosion empirical eguation, only now standard method dont use it2.In high temperatures, especially in the furnace pipe and turn oil inline naphthenic acid can accelerate
30、 sulfide corrosion. These organic acid can destroy sulfide protective film on the surface of metal and alloy, for example in lateral line tube fractions, for naphthenic acid destroy the membrane formed by hydrogen sulfide effect.C. temperatureGenerally speaking, all metal corrosion rate increases wi
31、th the rise of temperature, the naphthenic acid corrosion mainly appear in 220-400 of crude distillation regional. Lower than 220 the naphthenic acid content is very little in oil, and higher than 400 the rate of carboxyl off of the naphthenic acid in gas phase obviously improve , may be the naphthe
32、nic acid happened decompose or the coke formed in metal surface was protective 3 4.D, Fluid velocityFluid velocity is the main parameters affecting the naphthenic acid corrosion. For lack the ability of predict corrosion so use shear stress the fluid associated and Reynolds number appears more accurate, because they contain the density, viscosity and vaporization degree and pipe diameter of the liquid and steam in pipeline. Corrosion rate and wall shear stress is directly proportional. Generally, the higher acid value, th
