The Development Of Carbon Steel Corrosion Inhibitor And Studies Of Corrosion Inhibition In Hydrofluoric Acid

In practical industrial production, the equipment application of carbon steel is veryextensive, made of medium carbon steel materials such as plants or chemical plant reactor,drier, heat exchangers and other large machinery and equipment as well as oil pipelines all ofthe nation. For the equipment of carbon steel, commonly high silica scales and the metaloxide scales were cleaned by hydrofluoric acid, but ensure equipment the integrity need toadd corrosion inhibitor in hydrofluoric acid, so achieve the purpose of cleaning andprotection equipment. Predecessors have made a lot of researches on corrosion inhibitors inhydrofluoric acid, and the application is widely used in industry of large equipment, but lowcorrosion rate, high cost, poor to resistance high temperature, environmental pollution, etc.On the basis of forefathers’ research, this paper developed an applied to carbon steelequipment, the corrosion rate is high, the green environmental protection, high temperatureresistant, low cost of hydrofluoric acid compound corrosion inhibitor, corrosion effect issignificant.This article selects the mass fraction of3%hydrofluoric acid for pickling solution, andone-component corrosion inhibitor was studied for the amounts of compounds by classicweight-loss method. The three kinds of excellent corrosion inhibition compounds: thiourea,hexadecyl pyridine bromide,1227. Respectively study for the weight loss carbon steel ofdifferent concentration one-component inhibitor and the adsorption thermodynamicselectrochemistry, etc under the different temperature. Results show that the effect of losingweight is reducing when increase the amount of corrosion inhibitor to carbon steel graduallyat different temperatures, but when the concentration reaches a certain value, the weight-lossis almost the same. The adsorption effect of three kinds of compound is good, conform tosingle molecular layer adsorption, follow the law of the Langmuir adsorption and ΔG⁰<0show that the reaction is spontaneous; The electrochemical polarization curve show threekinds of material are mixed type corrosion inhibitor.According to actual industrial demand, need to find more efficient high temperaturecorrosion inhibitor. So we choose out several different compounds, using the orthogonalexperiment developed a corrosion rate, resistance to high temperature, resistant time,environmentally friendly composite corrosion inhibitor, and low price, and through thecorrosion performance of several chemical and physical methods to analyze and research. The data shows: add optimal proportion in3%hydrofluoric acid concentration composite inhibitorafter70℃, the corrosion rate can reach98.23%. And its high temperature resistance,resistance to timeliness, resistance to acid can be greatly improved, and the reaction time of24h specimens of carbon steel corrosion rate can reach the national standard (less than2.0g·h^-1·m^-2). To sum up, through the experiment developed a type of high temperaturecomposite hydrofluoric acid pickling corrosion inhibitors is excellent corrosion inhibition forcarbon steel.