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    • 专利摘要:
    The invention relates to a method for inhibiting the vanadic corrosion of hot parts of thermal equipment, which is based on the combined use of yttrium and magnesium. The combined use of yttrium and magnesium, implemented in a variable Y / Mg ratio, makes it possible: - compared to conventional magnesium inhibition, to reduce the emission of magnesium vanadate and to minimize performance losses fouling of hot parts including in the presence of alkali metals; - compared with the yttrium-only inhibition, to reduce the cost of the inhibition and to enhance the protection against combined corrosion by vanadium pentoxide and sodium sulphate.
    公开号:FR3044684A1
    申请号:FR1561782
    申请日:2015-12-03
    公开日:2017-06-09
    发明作者:Pierre Montage；Michel Moliere；David Trayhan；Maher Aboujaib；Sundar Amancherla；Krishnamurtjy Anand；Abdurrahman Khalidi；Matthieu Vierling
    申请人:GE Energy Products France SNC；
    IPC主号:
    专利说明:

    I NHI BL TORS OF THE CORROSI ON VANADI THAT BASED ON YTTRI UM AND
    MAGNESI UM
    The present invention relates to the inhibition of high-temperature corrosion of thermal equipment materials such as boilers, diesel engines, gas turbines, furnaces and process reactors, which burn in their homes fuels contaminated, in particular by vanadium. In particular, so-called heavy or residual fuels and crude oils, which will be referred to herein as the generic term "fuels", generally contain traces of metallic contaminants such as vanadium, sodium, potassium, calcium and lead for which treatment is required prior to combustion to mitigate the corrosive effects of these metals at high temperatures. In what follows, gas turbines or "turbines", which consist essentially of (i) a compressor; (ii) a fireplace itself constituted by a set of "combustion chambers" and (iii) an expansion turbine, will be taken as paradigms of thermal equipment but all the considerations contained in this document apply to thermal equipment in general. The "flame temperature" of a gas turbine, which largely determines its efficiency, is the temperature prevailing at the inlet of the expansion turbine and not that prevailing in the flames, which exceeds 2000 ° C on the flame front.
    The metal salts contained in the fuels can, when they are water-soluble, be extracted upstream of the thermal equipment; Thus, operations of "washing fuel" with water, followed by a water / fuel separation carried out using electrostatic or centrifugal separators are commonly used for the separation of water-soluble metal salts such as chlorides and sulphates of sodium, potassium and, in part, calcium.
    The vanadium derivatives contained in the fuels are organic in nature and have the major disadvantage of being not water-soluble but fat-soluble and, consequently, not removable by such a washing operation. The presence of such organic vanadium compounds in liquid fuels burned in thermal equipment is likely to cause high temperature corrosion of metallic materials in contact with the combustion gases. Indeed, according to the redox conditions prevailing in flames, vanadium reacts with oxygen to form one of the oxides VO, V203, V204 (or V02) or V205: while the first three oxides are refractory, with melting points exceeding 1500 ° C, on the contrary, vanadium pentoxide V205, which is formed in the highly oxidizing flames - especially in gas turbines - melts at a temperature of 670 ° C. This oxide is therefore in liquid form in the operating conditions of the turbine and the fraction that is deposited on the surfaces of the hot parts is likely to cause corrosion of the electrochemical type in molten salt medium. This "vanadic corrosion" can be more or less severe depending on the nature of the metal or alloy of the thermal equipment, the range of operating temperatures and the duration and operating conditions. It is also aggravated and more difficult to prevent when the fuel also contains alkali metals (sodium, potassium).
    The corrosive power of vanadium pentoxide V205 can be inhibited by "trapping" the latter in refractory compounds using chemical compounds known as "inhibitors". The classic representatives of these inhibitors are the alkaline earth compounds, such as calcium oxide, when the fuel does not contain sulfur, or more generally or magnesium salts, which can be used in water-soluble form. or fat-soluble. Such magnesium-based inhibitor additives, when introduced into a flame, decompose into magnesium oxide (MgO) which reacts with V205 to form a magnesium vanadate. A sufficient amount of magnesium is introduced to generate magnesium orthovanadate, of the formula Mg3V208, whose high melting point (1070 ° C.) enables the vanadium-laden particles to pass through the "hot vein" of the turbine in solid form. without causing corrosion of the hot parts of said turbine. The dosage of the inhibitor should be sufficient both to trap all the vanadium present in the fuel and to avoid the formation of vanadates having lower Mg / V stoichiometric ratios, namely pyrovanadate (Mg2V207) or metavanadate ( MgV208) which are insufficiently refractory to provide the desired inhibition effect.
    This magnesium inhibition leads to the formation of "magnesio-vanadic" combustion ash having high melting points and which contain: - on the one hand, magnesium orthovanadate (Mg3V208) which is produced by the reaction (1 ): (1) V205 + 3 MgO ^ Mg3V208 - on the other hand, an excess of magnesium oxide in the form of magnesium oxide (MgO) which partially transforms into magnesium sulfate (MgSO4).
    Indeed, in the focus, the sulfur contained in the fuel is oxidized to sulfur oxides "SOx" (ie SO2 + SO3) which also react with the magnesium oxide MgO to form magnesium sulphate (MgSO4): So there is, to a certain extent, a competition between V205 and sulfur oxides SOx in the reaction with MgO. This "parasitic" reaction of magnesium sulphate formation has the consequence that, in order to trap all the vanadium, a large excess of magnesium must be added relative to the stoichiometry of the reaction (1) with, in practice, a ratio of vanadium magnesium greater than or equal to 3 by weight. This large excess of magnesium is also useful, not only from a theoretical point of view, to ensure the conversion of vanadium magnesium orthovanadate but also from a practical point of view, to overcome possible inaccuracies or errors related to the determination in service of the vanadium content of the fuel.
    The magnesium inhibition treatment can be characterized by the Mg0 / V205 "dosage ratio" expressed on a molar basis, which will be noted "m". This ratio of dosage m is taken equal to 12.6 in the "conventional inhibition" method and is equivalent to the Mg / V ratio of 3 on the mass basis already mentioned. The corresponding material balance is therefore written in practice according to the following equation (2):
    (2) V205 + 12.6 MgO + 9.6 s S03 Mg3V208 + 9.6 s MgSO4 + 9.6 (1-s) MgO
    In this equation, "s" refers to the proportion of excess magnesium that is converted to sulphate and (1-s) that which is converted to oxide, the number decreasing with temperature.
    In the most general case of magnesium determination, the material balance is written according to the following equation (3): (3) V205 + mMgO + (m-3) s03 Mg3V208 + (m-3) [ s MgS04 + (1-s) MgO]
    In this equation, m> 3, with m = 12.6 in the case of conventional inhibition.
    If the magnesium sulfation process is ignored, the balance sheets (2) and (3) respectively equate to the following equations (2b) and (3b):
    (2b) V205 + 12.6 MgO Mg3V208 + 9.6 MgO
    (3b) V205 + mMgO Mg3V208 + (m-3) MgO
    The number (m-3) which appears in the right-hand side of equation (3b) represents the "relative magnesium excess", that is to say the excess of magnesium relative to one mole of V205; it is 9.6 in the case of conventional inhibition.
    The main advantage of magnesium inhibition lies in its moderate cost. Its main drawback lies in the fact that the magnesio-vanadic ash that is formed by the mineral mixture in the right-hand side of equation (3) tends to deposit significantly on the hot parts of the turbine and consequently to foul the latter, which progressively degrades the energy performance of said turbine. Indeed, a substantial fraction of the magnesio-vanadic ash resulting from this inhibition process is deposited on the walls of the combustion chambers and the components of the thermal equipment located downstream of them: we will speak of a process of deposition "of ashes. This process causes a gradual fouling of the thermal equipment as it is used and causes a consequential and progressive loss of its energy performance (power output and efficiency). To remedy this undesirable effect, it is conventionally carried out, periodically, either a dry cleaning or washing with water of these deposits of ash. Dry cleaning involves introducing into the equipment kept in operation a slightly abrasive material, free of corrosive compound or ash generator, so as to pick up part of the accumulated deposits on the walls of hot rooms. Water-washing the turbine is another, more efficient, method of performance restoration that involves injecting hot water after stopping and cooling the latter so as to dissolve the water-soluble fraction of magnesio-vanadic ash, that is to say magnesium sulfate, which has the effect of destabilizing the entire layer of ash and allow almost complete entrainment of said deposit; this method therefore makes it possible to recover almost completely the initial performances.
    In conclusion, due to their relatively fouling nature, the magnesio-vanadic ash, in addition to the power and efficiency losses mentioned above, require frequent stops of the turbine to perform such washing with water, which penalizes the availability of the production tool. In what follows, these losses of efficiency, power and availability will be collectively referred to as "loss of performance by fouling". Magnesium inhibition is - second significant disadvantage - sensitive to the presence of alkali metals which tend to reduce its effectiveness due to the formation of mixed vanadates of magnesium and for example sodium, in particular NaMg4 (VO4) 3, which melts at a temperature higher than 750 ° C and therefore lowers the melting point of the magnesio-vanadic ash, thus making them more adherent. In the rest of the description, this negative effect of alkali metals on the fusibility of magnesio-vanadic ash will be designated as "harmful effect of alkali metals".
    A third significant disadvantage arises from the fact that at high temperature, the magnesio-vanadic deposits become strongly fouling because of the partial or complete melting of Mg3V208 (if the temperature locally exceeds 1070 ° C) and secondly because the magnesium sulphate decomposes to magnesium oxide ("s" tending to 0 in equations (2) or (3) above), which oxide, completely insoluble in water, can not be removed by the washing operation. It follows that when the "flame temperature" of the turbine exceeds a limit of the order of 1090 ° C, the efficiency of the washing operation becomes very low and the restoration of performance is then problematic: this temperature 1090 ° C is therefore the "technical limit" of operation of turbines burning vanadium-contaminated fuels.
    As an alternative to magnesium inhibition, it has been proposed to use yttrium-based inhibitors. US Pat. No. 5,637,1 18 proposes indeed such a vanadium corrosion inhibitor which it also claims the effectiveness against combined corrosion by vanadium pentoxide and sodium sulfate. This document proposes to use yttrium in the form of a compound that generates Yttrium oxide (Y2O3) hot, which combines with V205 to form yttrium vanadate (YVO4) which is highly refractory. its melting point exceeding 1800 ° C and which remains solid at the operating temperatures of the gas turbine. The composition of such yttrium-based additives comprises in particular at least a stoichiometric amount of yttrium ester having at least four carbon atoms and a complexing agent (or "chelating agent"), namely 2,4-pentanediene. , soluble in the hydrocarbon fuels that are the fuels.
    The stoichiometric inhibition reaction of vanadium with yttrium is then written according to the following equation (4): (4) v205 + Y203 2 YV04
    The inventors of the present application have experimentally observed that this yttrium inhibition has the major advantage of generating only very low ash deposits on the hot parts of the thermal equipment and therefore greatly reduces the inherent losses of performance by fouling. to magnesium inhibition. Yttrium also has the advantage of being a very potent inhibitor, the reaction (4) always prevailing over that forming the sulphate Y2 (SO4) 3, and thus requiring theoretically only a ratio Y2O3 / V2O5 assay equals or slightly greater than the stoichiometric ratio which, according to reaction (4), is 1 on an atomic basis. However, in practical terms and as in magnesium inhibition, it is necessary that this ratio substantially exceeds 1 in order to overcome possible inaccuracies or errors related to the determination in service of the vanadium content in the fuel. Thus, the above-mentioned US Pat. No. 5,637,1 18 preferably recommends an atomic dosage ratio "y" = Y 2 O 3 / V 2 O 5 which is at least 1.25 on an atomic basis, the "relative excess" of yttrium, which is defined as the number (y-1), then being greater than or equal to 0.25.
    Under these conditions, given the high affinity of yttrium oxide (Y2O3) for sulfur trioxide, this excess of yttrium generates yttrium sulfate Y2 (SO4) 3 so that the The material balance of the inhibition with, for example, a Y / V atomic ratio of 1.25, is written according to the following equation (5): (5) V 2 O 5 + 1.25 Y 2 O 3 + 0.25 s' S03 2 YV04 + 0.25 s' Y2 (S04) 3
    In this equation, "s" is the proportion of excess yttrium that is converted to sulphate; it decreases only slightly with the temperature, remaining substantially equal to 1 in the temperature range of the inhibition application.
    In the case of any excess of yttrium, the material balance of the inhibition will be written according to the following equation (6): (6) V2O5 + y Y2O3 + (y-1) s' SO3 2 YV04 + (y-1) s' Y2 (SO4) 3
    The number "y" is at least 1 and the relative excess of yttrium is (y-1). It is important to note that when "y" is less than 1, which corresponds to an incomplete inhibition, yttrium sulphate is not formed because the formation of vanadate prevails, chemically, over that of sulphate.
    If the process of sulfation of yttrium is ignored, this material balance (6) is equivalent to the following simple equation (6b): (6b) V205 + y Y203 2 YV04 + (y-1) Y203
    It will be noted that the choice of the relative excess (y-1) of 0.25 recommended by US Pat. No. 5,637,118 (reaction (5) versus reaction (4)) is however far from being conservative, since this relative excess is of 9.6 in the case of conventional magnesium inhibition.
    A second advantage of yttrium inhibition, advanced in US Pat. No. 5,637,18, is that it is insensitive to the presence of alkali metals because, according to this same patent, it is effective against corrosion combined with vanadium pentoxide and sodium sulfate. However, the disadvantage of yttrium, as a metal equated with a "rare earth", is its cost is high.
    Vanadium compounds, like those of most so-called "heavy" metals, and especially V205 vanadium pentoxide, which is an acidic, reactive and "mobile" oxide once released into the ambient air, do not have an impact neutral on the environment. Installations that burn "fuels" are dependent on this situation, which is in fact independent of the thermal equipment used because it results directly from the use of such unrefined fuels: the conversion of V205 into alkaline earth vanadate, which results treatment of vanadium inhibition by magnesium, tends to reduce this impact because vanadium is then immobilized by a light metal (Mg) with high basic power, within the magnesium orthovanadate which is much less reactive than V205 but which can however undergo "leaching" processes in an aqueous medium or in a humid environment. Consequently, the combination of magnesium with vanadium has an attenuating effect on the impact of V205 on the environment, the magnesium oxide and sulphate present in excess (reaction (3)) being, moreover, benign compounds vis- about the environment.
    The case of yttrium inhibition seems a priori more complex because if this element is also endowed with a strong basic power able to immobilize vanadium, its use, necessarily in excess and according to the reaction (6), leads to the formation of yttrium sulphate which is soluble in water and can therefore contribute to the diffusion of yttrium in wet or aqueous environment. On the other hand, yttrium vanadate YV04 not only has a very high melting temperature (1810 ° C) but is also extremely stable: this very refractory and inert nature allows it to be "immobilized" in solid form right out of the the flame. It is, essential fact observed by the inventors of the present application, strictly insoluble in water. Bio-toxicity tests carried out by the inventors of the present application according to the OECD Standard 209 relating to plants, have shown that yttrium vanadate YV04 does not disturb the germination or the growth of the plants. This fact, which is a priori surprising, as regards the association of two so-called heavy metals (vanadium and yttrium), can possibly be explained by the fact that vanadium and yttrium are firmly immobilized one by the other "in the molecule YV04 which, insoluble in water and chemically inert, is therefore unreactive in biological processes.
    Moreover, the inventors of the present application have also observed experimentally that when an yttrium compound and a magnesium compound are placed in the presence of vanadium oxide, yttrium vanadate is always formed, in preference to vanadate of vanadium. magnesium. Therefore, if one introduces yttrium in default on vanadium - which is equivalent to using in equation (6b) a value of "y" less than 1 - and other proportion of magnesium in an amount sufficient to inhibit, according to reaction (3b), the vanadium fraction not inhibited by this yttrium deficient, then YV04 will be formed on the one hand, with the exception of Y2 (SO4) 3, and on the other hand, the classical products of magnesio-vanadic inhibition, namely: (MgSO 4 + MgO) and Mg 3 V 2 O 8 which, as indicated above, has an attenuating effect on the impact of V205 on the aqueous environment.
    Thus the inventors of the present application have discovered the interest of using a method of vanadium inhibition based on the combined use and in variable proportions: on the one hand, of yttrium used in default by compared to vanadium, yttrium is certainly an expensive metal but able to minimize performance losses by fouling of hot parts and otherwise free, being in default, environmental impact by aqueous route - secondly, magnesium, metal less expensive than yttrium and mitigating the environmental effects of V205 but causing significant performance losses by fouling of hot parts.
    In this new inhibition method called "combined inhibition", for each mole of V205 formed during the combustion is introduced: a number "y", strictly positive and strictly less than 1, of moles of yttrium oxide which inhibit y moles of V205 according to the following balance (7) derived from equation (6b) in which a value of y between 0 and 1 is chosen: (7) V205 + y Y203 2 y YV04 + (1 -y) V205 - an "m (1-y)" number of moles of magnesium, "m" being greater than equal to 3 so as to totally inhibit the "residual V205" which is vanadium pentoxide not inhibited by yttrium; the balance of the inhibition of this residual V205, which derives from equation (3b), is written according to the following equation (8):
    (8) (1-y) V205 + m (1-y) MgO3 (1-y) Mg3V208 + (1-y) (m-3) MgO
    The overall result of this "combined inhibition with yttrium and magnesium" is the complete inhibition of vanadium, with excess magnesium, which operates according to the following global equation (9):
    9) V205 + y Y203 + m (1-y) MgO 2y YV04 + (1-y) Mg3V208 + (1-y) (m-3) MgO
    This equation shows "y" and "m" as process variables. The choice of the parameter "m" is arbitrary, however, knowing that the choice of a value of m greater than 15, in addition to the additional cost related to magnesium consumption, would make the reduction of "performance losses by fouling" very difficult; the parameter "m" will therefore preferably vary from 3 to 15 and may especially be equal to 12.6, for example if the value of the conventional magnesium inhibition is kept, the relative excess (m-3) being then 9.6 and the atomic ratio Mg / Y, which is written as 0.5 m (1-y) / y, no longer depends on the value of y.
    The vanadium corrosion inhibition method according to the invention therefore uses two vanadium inhibiting substances, which are yttrium and magnesium, and the combination of which makes it possible, in addition to an effective inhibition of said vanadic corrosion: to control the the environmental impact of ashes to the extent that no V205 vanadium pentoxide, oxide, yttrium sulphate and limited quantities of Mg3V208 magnesium orthovanadate are produced, which is the only product likely to diffuse into the environment through wet track; - to control the "deposition of ashes" which is especially weaker as the parameter "y" is close to unity.
    This possibility of controlling the deposition of ashes is particularly interesting. Indeed, it is possible: - on the one hand, to increase the flame temperature beyond the "technical limit", of the order of 1090 ° C, which has been defined previously without encountering a problem major removal of ash deposits during washing with water turbine; - on the other hand, depending on the experience acquired during the operation of the thermal equipment, to determine: • either the minimum value "yi" of the parameter "y" allowing the operating time between two washing operations the turbine does not fall below a pre-determined "T" value while respecting a maximum allowable loss of performance: this operating criterion will be referred to as the "minimum operating time criterion between two washes "; • or the minimum value "y2" of this same parameter "y" allowing the "rate of loss of performance" (dP / dt) by fouling does not exceed, in absolute value, a threshold "δ" determined at the in advance: this operating criterion will be referred to as the "performance loss minimization criterion".
    The appended FIG. 1 illustrates this double point. In this figure, the performance of the "P" turbine, which is either the power produced (in kW / h) or the efficiency (in%), is a function of the time "t" (in hours). Performance level (3) is the original performance level of this turbine. The performance level (4) is the threshold from which the operator decides to carry out a washing operation, a threshold that will for example be equal to 95% of the original performance (3), given that the operator may also, less frequent strategy, choose to wash the turbine after a defined and invariable number of hours of operation as is the case in Example 2 embodiment of the invention below. The time intervals (5), (6), (7) and (8) represent four operating times of the turbine during which four different choices were made for the parameter "y". These periods are interspersed between washing operations (9) to (13) during which the power produced (14) to (18) is zero but at the end of which the turbine returns to a level of performance (19) to (23) identical to the original level (3).
    During the operating time (6), the value adopted for "y" is equal to "y ^" which is the value ensuring an operating time between two washes equal to the lower limit "T" predetermined by the operator, without exceed a performance loss of 5%. In other words, this operating period (6) just satisfies the "criterion of minimum operating time between two washes" defined above.
    During the operating time (5), the value adopted for "y" is less than y ^ so that the duration of this operating period (5) is shorter than "T": this operating period (5) does not exceed not meet the "minimum operating time criterion between two washes".
    During the operating period (7), the value adopted for "y" is equal to "y2" which is the value ensuring, in absolute value, a rate of loss of performance, represented by the slope (24), equal to the upper limit δ predetermined by the operator. In other words, this period of operation (7) just satisfies the "criterion of minimization of performance losses".
    Finally, during the operating period (8), the value adopted for "y" is greater than y2 so that the rate of loss of performance over this period (8), which is represented by the slope (25), is lower than at the rate of loss of performance δ predetermined by the operator and thus satisfies, with a certain margin, the "criterion of minimization of performance losses". The operator can, in a prior experience acquisition phase, determine the values of yi and y2 by following, for a given fuel quality, the performance of his machine according to the parameter "y" of the combined inhibition .
    FIG. 1, which has just been described and was introduced in the present description as a mere illustration, does not claim to cover exhaustively all the relative dosages between Y and Mg which are made possible by the invention and which depend on the parameters y and m: one could consider for example the following cases: y> yi; y <y2; yi <y <y2; 3 <m <12.6; etc ...
    The combined inhibition method according to the invention therefore lends itself to a multiple number of embodiments that derive, on the one hand, from the choice of the parameters "y" and "m" and, on the other hand, from the modes of introduction. both inhibitors.
    Finally, it should be noted that the inventors of the present application have also observed that the combined use of magnesium and yttrium improves, compared with yttrium alone, the quality of the combined corrosion protection of pentoxide. vanadium and sodium sulfate, a protection which is already an alleged advantage of the process described by US Pat. No. 5,637,181. This result can possibly be explained by the formation of a mixed sodium / magnesium sulphate in which the sulphate of sodium is blocked according to the following reaction (10): (10) Na 2 SO 4 + 3 MgSO 4 Na 2 Mg 3 (SO 4) 4.
    Thus, the invention relates to a method for inhibiting the corrosion of high temperature hot rooms of a thermal equipment burning a contaminated fuel including vanadium in the presence or absence of sodium. This process is characterized in that a mole of vanadium pentoxide formed during the combustion is introduced into a furnace of said thermal equipment: a number "y", varying from 0.05 to 0.95, of mole of yttrium oxide, and a number of moles of magnesium oxide equal to "m * (1-y)", "m" ranging from 3 to 15 and preferably being equal to 12.6,
    the vanadium inhibition being carried out according to the reaction: f205 + y Y203 + m (1-y) MgO 2y YVO4 + (1-y) Mg3V208 + (1-y) (m-3) MgO wherein y and m are as defined above. The vanadium inhibition is then complete because carried out with an excess of magnesium, according to the overall reaction (9): (9) V205 + y Y203 + m (1-y) MgO 2 y YVO4 + (1-y) Mg3V208 + ( 1-y) (m-3) MgO.
    It is understood that, although the "oxide" category is used to define the yttrium and magnesium compounds to be introduced, it is also possible to introduce any other yttrium (or magnesium) compound capable of generating in the furnace yttrium oxide (respectively magnesium oxide). It is also understood that the expression "introduced into the home" does not necessarily mean a direct injection into the home, the introduction can be performed upstream of the home in any circuit leading to said home.
    This mode of "combined inhibition" has particular advantages: - compared with yttrium inhibition as described in US Pat. No. 5,637,18, to reduce the cost of inhibition and to enhance the protection against combined corrosion by vanadium pentoxide and sodium sulphate; - compared with conventional magnesium inhibition: • to reduce the emission of leachable magnesium orthovanadate, • to reduce the ash deposition on hot parts of the thermal equipment as well as the consequent losses of performance, • to reduce the "harmful interference of alkali metals" that may be present in the fuel oil coming into the firebox: performance losses are therefore minimized by fouling of hot parts, even in the presence of alkali metals, • the flame temperature is increased beyond the "technical limit" of the order of 1090 ° C.
    In one embodiment of the invention, the fuel is also contaminated with sodium.
    In one embodiment of the invention, the thermal equipment is a gas turbine whose flame temperature is less than, equal to or greater than 1090 ° C.
    In one embodiment of the invention, it is possible to use two separate inhibitors based respectively on yttrium and magnesium precursors, for example: the yttrium oxide is generated from a liposoluble or water-soluble precursor, said precursor being contained in an additive called yttrium-based inhibitor, and - the magnesium oxide is generated from a liposoluble or water-soluble precursor, said precursor being contained in an additive called magnesium-based inhibitor.
    In another embodiment of the invention, it is possible to use an inhibitor combining these two precursors, the additives concerned being able to be hydrophilic or fat-soluble.
    In another embodiment of the invention: the precursor of the yttrium oxide is preferably yttrium nitrate, an yttrium sulphonate, an yttrium carboxylate, an yttrium chloride or a compound nanometric yttrium suspended in a hydrophilic or lipophilic solvent, and - the precursor of the magnesium oxide is an inorganic magnesium salt, a magnesium sulfonate, a magnesium carboxylate or a nanometric magnesium compound suspended in a solvent hydrophilic or lipophilic.
    In another embodiment of the invention, one of the two inhibitors is introduced directly into the fuel or into the furnace or upstream of the furnace in any of the furnace supply circuits of the thermal equipment and the other inhibitor is introduced in a different location from the first inhibitor, for example by mixing in the fuel, for example in a mixing or storage or recirculation tank, before being conveyed into any of the furnace power supply circuits of the thermal equipment.
    In another embodiment of the invention: either the two inhibitors are introduced directly into the fuel or into the furnace or upstream of the furnace in one of the supply circuits of the furnace, or they are mixed directly with the furnace; fuel for example in a mixing tank before being routed in any of the circuits leading to the focus of the thermal equipment
    By circuits is meant the supply of the hearth of the thermal equipment, for example: a fuel supply circuit or a water supply circuit or a water / fuel emulsion circuit or a circuit for atomizing air.
    Moreover, by injection is meant directly in the hearth, when for example an inlet intended for injection is used directly into the hearth of a product, either for cleaning or to improve combustion. For example, in a gas turbine combustion chamber, particles are injected to clean the first turbine stages.
    Thus according to one embodiment of the method of the invention, the injection of any one of the two inhibitors is carried out: either upstream of the furnace and through a fuel supply circuit or a circuit supplying water or an atomizing air circuit of said furnace, either directly into the furnace and in particular through a quill used for the injection of particles intended for cleaning the turbine or through a quilting dedicated.
    In another embodiment of the invention, the parameter "y" is chosen to be at least equal to 0.9. In this case, the performance losses due to fouling and the emission of magnesium vanadate particles are then minimized.
    In another embodiment of the invention, the parameter "y" is chosen to be at most equal to 0.1. In this case, the cost of the inhibition is then minimized. The balance (9) of the inhibition is then written, by putting y = (1 - e) according to equation (11): (11) V205 + (1 -e) Y203 + me MgO 2 (1 -e) ) YV04 + e Mg3V208 + e (m-3) MgO, the number e having a low value, equal for example to 0.1.
    In another embodiment of the invention, the parameter "y" is chosen to be greater than a value "y-" allowing a rate of loss of power of the thermal equipment less than a limit defined at advance.
    In another embodiment of the invention, the parameter "y" is chosen to be greater than a value "y2" allowing to have an operating time, between two consecutive washings of the turbine, greater than a limit defined at advance.
    The following examples are intended to illustrate the invention.
    EXAMPLES OF REALI SATI ON
    Example 1
    A highly contaminated fuel containing 150 mg of vanadium (V) per kilogram (ie 150 / 50.9 = 2.97 milli-atom of V per kg of fuel) is burned in a gas turbine whose flame temperature is of 1088 ° C (thus practically at the level of the "technical limit" of 1090 ° C) and which produces a power of 101 MWe ("MW electric").
    The criterion chosen by the operator for triggering a turbine wash is a loss of power by fouling of 5% which leads the operator to stop the turbine when the latter has lost 0.05 * 101 = 5.05 MW and therefore went down to 101 - 5.05 or about 96 MW.
    It initially practices a conventional magnesium inhibition which requires the injection of 150 * 3 = 450 mg of Mg per kg of fuel and which is carried out according to the following balance sheet (2b):
    (2b) V205 + 12.6 MgO Mg3V208 + 9.6 MgO The emission of magnesium orthovanadate (MW = 302.7), calculated from the number of vanadium atoms, is: [(150/50, 9) / 2] * 302.7 = 446 mg of Mg3V208 per kg of fuel burned.
    Moreover, the operator observes that the power loss by fouling of its turbine takes place at an average rate of 51 kWe per hour of operation which leads to an operating time of 5.05 / 0.051 or about 100 hours between two washes consecutive. The operator decides to switch to a mode of inhibition combined with yttrium and magnesium according to the process according to the invention because it wishes on the one hand to reduce the emission of magnesio-vanadic particles and on the other hand to increase the availability of its machine by reducing the rate of power loss by fouling by a factor of 3: it therefore aims for a power loss rate of the order of: 51/3 = 17 kW / h. Based on previous tests conducted during which he monitored the power loss as a function of the "y" parameter of the combined inhibition mode, the operator determined that the value "y! "To achieve this goal is of the order of 0.93 taking the value of 12.6 for the parameter" m "which, according to equation (9) leads to the inhibition report (12 ) next: 12) V205 + 0.93 Y203 + 0.882 MgO 1.86 YV04 + 0.07 Mg3V208 + 0.672 MgO.
    In this combined inhibition, the atomic mass of yttrium being 88.9 g / mol, the operator must therefore inject: in yttrium: 2.97 * 0.93 * 88.9 = 245.6 mg of Y per kg of fuel. magnesium: 450 / 12.6 * 0.88 = 31.4 mg of Mg per kg of fuel.
    This change in mode of inhibition increases the magnesium orthovanadate emission from 446 mg to 446 * 0.07 = 31.2 mg of Mg3V208 per kg of burnt fuel: it is therefore divided by a factor of 14.
    At the same time, the rate of power loss is effectively reduced from 51 kW / h to around 16.5 kW / h. Therefore the possible operating time between two washes goes from 100 hours to 5.05 / 0.0165 = 306 hours. The operator has managed to triple the operating time of its turbine between two washes.
    As a complete washing operation, which involves stopping, cooling, washing with water, spinning, and restarting the turbine, lasts about 15 hours, the availability of the gas turbine which was 100 / (100 + 15) = 90% with conventional magnesium inhibition becomes: 306 / (306 + 15) = 95% with yttrium inhibition. The operator thus gains 5% of machine availability while dividing by 14 the emission of magnesium orthovanadate.
    As inhibitors based on magnesium and yttrium, it uses an aqueous solution containing 2% of magnesium in the form of magnesium nitrate and 15.6% of yttrium in the form of yttrium nitrate, a solution that it injected directly into the fuel circuit in the low-pressure part of the fuel circuit, through a high-speed rotary mixer which ensures the emulsification of this solution in the fuel. Given the large quantities of vanadium to be inhibited, this option of water-soluble inhibitors is economically more interesting than an option of fat-soluble inhibitors.
    Example 2
    A lightly contaminated fuel containing 30 mg of V per kilogram (ie 30 / 50.9 = 0.589 milli-atom of V per kg of fuel) is burned in a gas turbine whose flame temperature is also 1088 ° C. (so practically at the "technical limit" of 1090 ° C) and produces a power of 38 MWe ("MW electric"). The operator also practices, initially, a conventional magnesium inhibition which requires the injection of 30 * 3 = 90 mg of Mg per kg of fuel and is carried out according to the following balance sheet (2b):
    (2b) V2O5 + 12.6 MgO Mg3V208 + 9.6 MgO
    This time, the desire of the operator is not to increase the availability of his machine because his operating strategy is to trigger a washing-turbine every 6 days (ie every 145 hours) because it is him It is advantageous to carry out these washes on Sundays, days of low electrical demand. Instead, he wants to increase the productivity of his installation with the goal of gaining about 5% in electricity production.
    With conventional magnesium inhibition, turbine impeller power loss occurs at an average rate of 21 kWe per hour of operation. After 145 hours of walking, the turbine lost 0.021 * 145 = 3.045 MWe and dropped to 38 - 3.045 = 34.96 MWe. As a result, the average power produced during the 145 hours of operation between two washes is (38 + 34.96) / 2 = 36.48 MWe and the amount of electricity generated is 145 * 36.48 = 5290 MWh. Based on previous tests conducted during which he monitored power loss as a function of the "y" parameter of the combined inhibit mode, the operator determined that the value "y2" for to achieve this objective is of the order of 0.75 taking the value of 12.6 for the parameter "m" which, according to equation (9) leads to the inhibition report (13): (13) ) V205 + 0.75 Y 2 O 3 + 3.15 MgO 3 1.5 YV0 4 + 0.25 Mg 3 V 2 O 8 + 2.4 MgO.
    In this combined inhibition according to the process according to the invention, the operator must therefore inject: in yttrium: 0.589 * 0.75 * 88.9 = 39.2 mg of Y per kg of fuel. magnesium: 90 / 12.6 * 3.15 = 22.5 mg of Mg per kg of fuel. The operator notes that the rate of loss of power has increased from 21 kW / h to around 10.05 kW / h. After 145 hours, the turbine thus lost 0.0105 * 145 = 1.523 MWe and thus went down to 38 - 1.523 = 36.477 MWe. Therefore the average power produced during the operating time of 145 hours between two washes is (38 + 36.477) / 2 = 37.24 MWe.
    Thus over a period of operation between two washes, the operator who wanted to increase its production earns on average 37.24 - 34.96 = 2.28 MWe: over this period it produces a supplement of 2.28 * 145 = 330 MWh of electricity. The gain obtained by switching to combined inhibition with yttrium and magnesium according to the process according to the invention is 330/5290 = 6.2%. He therefore slightly exceeded his goal of gain of 5%.
    It can also be determined that this change in mode of inhibition increases the magnesium orthovanadate emission from 446 mg to 112 mg of Mg3V208 per kg of fuel burned: the latter is therefore divided by a factor of about 4. The operator uses separate inhibitors of magnesium and yttrium, both of the fat-soluble type: the magnesium-based inhibitor is a magnesium sulphonate solution containing 11% magnesium in a heavy aromatic naphtha and the inhibitor-based Yttrium is a solution of yttrium octoate with 5% yttrium, also in a heavy aromatic naphtha. These inhibitors are injected, on-line mode in the low-pressure part of the fuel circuit, using two separate metering pumps but at the same point where is installed a single static mixer that ensures their mixing with the fuel.
    Example 3
    The turbine and the fuel that it burns are identical to those of Example 2 above. The operator who initially operates by applying the conventional magnesium inhibition, has at the turbine inlet, a purified alkaline fuel oil through a process of washing fuel with water which is carried out by a system of treatment of fuel oil based on centrifugal separators and which ensures a residual sodium content of less than 1 ppm by weight at the inlet of the turbine, which avoids the "harmful effect of metals" on the clogging of the turbine.
    It observes an unexpected disruption of its fuel treatment system leading to a residual sodium content of the order of 10 ppm. Correlatively, he observes that the rate of loss of power by fouling goes from 21 kWe to 30 kWe, which degrades the production and the yield of his machine.
    He then decides to switch to an inhibition mode combined with yttrium and magnesium according to the present invention with the same parameter "y" as in Example 2, y = 0.75.
    Once in this combined mode of inhibition and before it could solve the malfunction of its fuel treatment system leading to a high sodium content at the turbine inlet, the operator observes, over two operating periods. 100 hours, that the rate of loss of power is only 12 kW / h, a reduction by a factor of 30/12 = 2.5 of the loss of performance that it experienced when it applied the inhibition. conventional magnesium.
    Example 4
    The turbine and the fuel that it burns are identical to those used in Example 2 above. The operator initially operates by applying the conventional magnesium inhibition and here, too, wishes to increase the productivity of its plant by increasing the efficiency of its turbine and plans to do so at a flame temperature of 1140 ° C, which corresponds to at an increase of 47 ° C from the initial value of 1088 ° C.
    For this he decides to switch to an inhibition combined with yttrium and magnesium according to the process according to the invention, with a value "y" of 0.95 with the value 12.6 of the parameter "m". The corresponding inhibition equation (14) is as follows:
    (14) V205 + 0.95 Y203 + 0.63 MgO 1.9 YV04 + 0.05 Mg3V208 + 0.48 MgO
    During several cycles of operation-washing, the operator notes that: - the initial power (washed machine) goes from 100 MWe to 112 MWe, - the rate of power loss remains at the level of 15 kW per hour.
    In addition, the emission of orthovanadate goes from 892 mg to 892 * 0.05 = 45 mg per kg of burned fuel.
    权利要求:
    Claims (9)
    [1" id="c-fr-0001]
    1. A method of inhibiting the vanadic corrosion of hot parts of a thermal equipment burning a contaminated fuel including vanadium, said method being characterized in that it is introduced directly into the home or in one of its circuits. supply or in a tank of said thermal equipment, per mole of vanadium pentoxide formed during combustion: a number "y", varying from 0.05 to 0.95, of mole of yttrium oxide, and a number of moles of magnesium oxide equal to "m * (1-y)", "m" varying from 3 to 15 and preferably being equal to 12.6, the vanadium inhibition being carried out according to the reaction: V205 + y Y 2 O 3 + m (1-y) MgO 2 y YVO 4 + (1-y) Mg 3 V 2 O 8 + (1-y) (m-3) MgO wherein y and m are as defined above.
    [2" id="c-fr-0002]
    2. Method according to claim 1, characterized in that the fuel is also contaminated with sodium.
    [3" id="c-fr-0003]
    3. Method according to claim 1, characterized in that the thermal equipment is a gas turbine whose flame temperature is less than, equal to or greater than 1090 ° C.
    [4" id="c-fr-0004]
    4. Method according to any one of the preceding claims, characterized in that: - yttrium oxide is generated from a liposoluble or water-soluble precursor, said precursor being contained in an additive called yttrium-based inhibitor and in that - the magnesium oxide is generated from a fat-soluble or water-soluble precursor, said precursor being contained in an additive called a magnesium-based inhibitor.
    [5" id="c-fr-0005]
    5. Process according to any one of claims 1 to 3, characterized in that: the precursor of the yttrium oxide is an inorganic yttrium salt, an yttrium sulphonate, an yttrium carboxylate, a yttrium chloride, or a nanometric yttrium compound suspended in a hydrophilic or lipophilic solvent, and in that - the precursor of the magnesium oxide is an inorganic magnesium salt, a magnesium sulfonate, a magnesium carboxylate or a nanoscale magnesium compound suspended in a hydrophilic or lipophilic solvent.
    [6" id="c-fr-0006]
    6. Method according to any one of the preceding claims, characterized in that: - either the two inhibitors are introduced directly into the fuel or into the furnace or upstream of the furnace in one of the furnace supply circuits, - either one of the two inhibitors is introduced directly into the fuel or into the furnace or upstream of the furnace in any one of the furnace supply circuits of the thermal equipment and the other inhibitor is introduced in a different place from the first.
    [7" id="c-fr-0007]
    7. Method according to any one of the preceding claims, characterized in that the injection of any one of the two inhibitors is carried out: either upstream of the hearth and through a fuel supply circuit or a water supply circuit or an atomizing air circuit of said furnace, either directly in the furnace and in particular through a piercing used for the injection of particles intended for cleaning the turbine or through a dedicated stitching.
    [8" id="c-fr-0008]
    8. Method according to any one of the preceding claims, characterized in that the parameter "y" is chosen to be at least equal to 0.9.
    [9" id="c-fr-0009]
    9. Method according to any one of claims 1 to 7, characterized in that the parameter "y" is chosen to be at most equal to 0.1.
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    同族专利:
    公开号 | 公开日
    US20170158978A1|2017-06-08|
    FR3044684B1|2017-12-08|
    US10184091B2|2019-01-22|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    FR2229861A1|1973-05-14|1974-12-13|United Aircraft Corp|
    US5637118A|1994-06-30|1997-06-10|United Technologies Corporation|Vanadium corrosion inhibitor|
    WO2004026996A1|2002-09-17|2004-04-01|Systemseparation Sweden Ab|Fuel additive composition and its preparation|
    FR3004733A1|2013-04-23|2014-10-24|Ge Energy Products France Snc|PROCESS FOR IMPLEMENTING BI-METALLIC ADDITIVES FOR INHIBITING VANADO CORROSION IN GAS TURBINES|
    WO2016162718A1|2015-04-10|2016-10-13|Ge Energy Products France Snc|Method of operating a gas turbine with yttrium and/or magnesium injection|EP3438326A1|2017-08-01|2019-02-06|General Electric Company|Systems and methods for vanadium corrosion inhibitors|
    US10577553B2|2017-08-09|2020-03-03|General Electric Company|Water based product for treating vanadium rich oils|
    US11015252B2|2018-04-27|2021-05-25|Applied Materials, Inc.|Protection of components from corrosion|
    CN111718767A|2020-06-30|2020-09-29|吉林钜润环保科技有限公司|Yttrium-based oil-soluble high-temperature vanadium inhibitor and preparation method thereof|
    法律状态:
    2016-12-22| PLFP| Fee payment|Year of fee payment: 2 |
    2017-06-09| PLSC| Publication of the preliminary search report|Effective date: 20170609 |
    2017-12-21| PLFP| Fee payment|Year of fee payment: 3 |
    2019-09-27| ST| Notification of lapse|Effective date: 20190906 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1561782A|FR3044684B1|2015-12-03|2015-12-03|VANADI CORROSION INHIBITORS BASED ON YTTRIUM AND MAGNESIUM|FR1561782A| FR3044684B1|2015-12-03|2015-12-03|VANADI CORROSION INHIBITORS BASED ON YTTRIUM AND MAGNESIUM|
    US15/368,483| US10184091B2|2015-12-03|2016-12-02|Yttrium and magnesium based vanadium corrosion inhibitors|
    PCT/US2016/064870| WO2017096334A1|2015-12-03|2016-12-03|Yttrium and magnesium based vanadium corrosion inhibitors|
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