Corrosion inhibitors pipeline

Uses Emulsifier in degreasers, pine oil cleaners, d-Limonene cleaners, sanitation products antistat in vehicle cleaners, textiles used in corrosion inhibitors, pipeline drag reducers, rheology modifiers, organoclay suspensions, personal care products... 

AH corrosion inhibitors in use as of this writing are oil-soluble surfactants (qv) which consist of a hydrophobic hydrocarbon backbone and a hydrophilic functional group. Oil-soluble surfactant-type additives were first used in 1946 by the Sinclair Oil Co. (38). Most corrosion inhibitors are carboxyhc acids (qv), amines, or amine salts (39), depending on the types of water bottoms encountered in the whole distribution system. The wrong choice of inhibitors can lead to unwanted reactions. Eor instance, use of an acidic corrosion inhibitor when the water bottoms are caustic can result in the formation of insoluble salts that can plug filters in the distribution system or in customers vehicles. Because these additives form a strongly adsorbed impervious film at the metal Hquid interface, low Hquid concentrations are usually adequate. Concentrations typically range up to 5 ppm. In many situations, pipeline companies add their own corrosion inhibitors on top of that added by refiners. 

The structures used (platforms) require monitoring in addition to sub-sea pipelines, satellite wells and other equipment (e.g. manifolds) on the sea floor. Corrosion inhibitors are widely used in internal-streams (from the reservoir and many of the downstream operations). Corrosion monitoring can provide valuable data for assessing the effectiveness of the inhibitors used and for optimising dosage rates. 

These same diamine materials find further application in, for example, formulations for mussel and barnacle control in large once-through, condenser cooling systems, as corrosion inhibitors and biostats for hydrostatic testing of oil and gas pipelines, and as corrosion inhibitors in food industry retort cookers. 

The history of corrosion inhibitors and neutralizers and their invention, development, and application in the petroleum industry is documented by a review of Fisher [605]. Early corrosion inhibitor applications in each of the various segments of the industry, including oil wells, natural gas plants, refineries, and product pipelines, are reviewed. 

Corrosion inhibitors, which are used for the protection of oil pipelines, are often complex mixtures. The majority used in oil production systems are nitrogenous and have been classified into the following broad groupings ... 

The preparation of a corrosion inhibitor in the solid form allows the development of a new technique of continuous intensive anticorrosive protection for gas and oil pipelines, as well as for acidizing operations of oil wells [746]. The controlled dissolution of the solid inhibitor creates a thin protective layer on the metallic surface that prevents or minimizes the undesirable corrosion reactions. 

Another analytic procedure based on HPLC has been developed for the quantitative determination of nitrogen-containing corrosion inhibitors [1194]. The method was primarily developed for the analysis of certain oil pipeline condensate samples. 

Inhibitors may be classified according to their solution properties as either oil-soluble inhibitors, water-soluble inhibitors, or dispersible inhibitors. Chemical inhibitors act as film formers to protect the surface of the pipeline. Corrosion inhibitors, used for the protection of oil pipelines, are often complex mixtures. The majority of inhibitors used in oil production systems are nitrogenous and have been classified into the broad groupings given in Table 11-4. Typical corrosion inhibitors are shown in Table 11-5. For details, see also Chapter 6. 

M. A. Keimard and J. G. McNulty. Conventional pipeline-pigging technology Pt 2 Corrosion-inhibitor deposition using pigs. Pipes Pipelines Int, 37(4) 14-20, July-August 1992. 

K. C. Koshel, J. S. Bhatia, S. Kumar, and A. K. Samant. Corrosion problem in kalol injection water pipeline system and its control by using corrosion inhibitors. Ongc Bull, 25(2) 115-133, December 1988. 

Corrosion inhibitors used to protect fuel system components such as storage tanks, pipelines, and combustion system equipment are typically dissolved in the fuel and delivered to the metal surface with the fuel. The inhibitor is deposited onto exposed metal surfaces as the fuel passes through the fuel distribution and handling system. 

The protective film formed by corrosion inhibitors can act as a lubricating film to help in reducing fluid friction within a pipeline. This property can be measured and is termed the C Factor. This friction factor is expressed as follows ... 

C Factor ratings between 155 and 160 are typical for pipelines that have been newly constructed effectively treated with a film-forming corrosion inhibitor. A low C Factor indicates that there is higher internal friction within a pipeline system, and thus a reduction in efficiency. 

For this reason, it is recommended that addition of corrosion inhibitor to previously uninhibited systems be closely monitored. Initial low level addition followed by a gradual increase in the corrosion inhibitor treat rate will help to minimize the removal of pipeline rouge and filter plugging problems. 

It is visualized that the proposed coal slurry pipelines could be used as biological plug flow reactors under aerobic conditions. The laboratory corrosion studies under dynamic test conditions show that use of a corrosion inhibitor will limit the pipeline corrosion rate to acceptable levels. 

Most microbial desulfurization studies have been conducted in the laboratory shake-flask type experiments, and the major drawback cited against such a process has been that the rates of pyritic sulfur removal were not high enough to reduce the reactor size to a reasonable capacity (2,6). In this study an attempt has been made to determine the effectiveness of T. ferrooxidans under simulated pipeline conditions for pyritic sulfur removal. Since the microbial desulfurization process is conducted under acidic environment, an attempt has been made to determine the corrosion rates under dynamic conditions using Illinois //6 and Indiana 3 bituminous coals and to investigate the effectiveness of a commercial corrosion inhibitor for controlling the corrosivity. 

The addition of T. ferrooxidans in salt medium at the desired concentration to the coal/water slurry increased the corrosion rates for both the coals tested. The corrosion rates for the 72-hour and 500-hour experiments in the presence of T. ferrooxidans in salt medium with 10 wt% slurry of Illinois //6 ranged from 4.2 X 10 3 ipy to 1.41 X 10 ipy, respectively. However,the introduction of up to 10 ppm of a commercial corrosion inhibitor, Calgon T G-10, inhibited the corrosion rates with Illinois 6 and Indiana 3 coals to very low levels approaching those obtained with the deionized water. Balck Mesa pipeline has used this corrosion inhibitor on a regular basis with very satisfactory results. 

About 80% pyritic sulfur removal has been achieved by microbial desulfurization of Illinois 6 and Indiana 3 coals using T. ferrooxidans in laboratory shake-flask experiments and in a two-inch pipeline loop. The 10 to 25 wt% coal/water slurry was recirculated at 6-7 ft/sec for 7 to 12 days at 70-90°F. Results also show that the rates of bacterial desulfurization are higher in the pipeline loop under turbulent flow conditions for particle sizes, 43 to 200/m as compared to the shake-flask experiments. It is visualized that the proposed coal slurry pipelines could be used as biological plug flow reactors under aerobic conditions. The laboratory corrosion studies show that use of a corrosion inhibitor will limit the pipeline corrosion rates to acceptable levels. 

Industrial applications of corrosion inhibitors are too numerous to cover in the present context. The inhibitor industry amounts to several billion dollars annually. Applications of inhibitors in petroleum production, oil and gas wells and pipelines, potable water, water cooling towers, acid systems, automobile antifreeze systems, paints, boiler waters,... 

For cross country lines containing oil or gas, the corrosive constituents such as water, carbon dioxide, and hydrogen sulfide are usually reduced to a very low level before the fluid enters the line. The lost efficiency required to pump the unwanted constituents and the extra wall thickness required for corrosion allowance usually cannot be economically justified. Even with cleanup systems, some water will get into pipelines. In oil lines, oil soluble corrosion inhibitors usually prevent attack by water settling in low spots, etc. Gas lines are usually dehydrated to 60% of saturation to avoid corrosion from condensing water containing dissolved carbon dioxide. Molecular sieves that reduce water to 5 ppm have proved necessary in lines containing 100% carbon dioxide. 

Corrosion Inhibitors—inhibit ferrous corrosion in in pipelines, storage tanks, and vehicle fuel systems... 

It is usefiil to consider the case of an installation of a subsea gathering system for a natural gas production field. The pipeline design for a new gas production facility consisted of 20 cm diameter subsea gathering lines (flow lines) emptying into a 19 km, 50 cm diameter subsea transmission gas pipeline. The pipeline was to bring wet gas from an offshore producing area to a dehydration facility on shore. The internal corrosion was estimated to be 300-400 mpy. The corrosion mitigation options considered were (i) carbon steel treated with a corrosion inhibitor (ii) internally coated carbon steel with a supplemental corrosion inhibitor (iii) 22% Cr duplex stainless steel (iv) 625 corrosion-resistant alloy (CRA). The chance for success was estimated from known field histories of each technique, as well as the analysis of the corrosivity of the system and the level of sophistication required for successful implementation (Table 4.42). 

Control of Internal Corrosion of Pipelines Using Inhibitors.425... 

Inhibitors for Control of Corrosion in Pipeline Coating Industry.427... 

However, in today s harsh oil/gas production environments where facilities and equipment are becoming old, with attendant increases in maintenance costs, the use of inhibitors as opposed to the use of other expensive corrosion mitigation methods becomes an obvious choice as cost-saving solutions to extend the life of assets and infrastructures. Researchers have now focused on the use of volatile inhibitors mixed with oil and water-soluble inhibitors for use in mitigating corrosion in multiphase systems such as in the control of internal corrosion of pipelines and corrosion of... 

Other methods include use of intelligent pigging as well as corrosion prediction models developed by C. De Waard and some other modifications that have been published and commercialized by several other investigators. However, after prediction and/or detection of corrosion incidents inside the pipelines, the most cost-effective method of control is the use of corrosion inhibitors. These are usually amine based and are thus water dispersible. They are usually blended with vapour phase inhibitors and probably some flow enhancers. 

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