EP0007862B1 - Liquid agent for the chemical destruction of soot and method of application - Google Patents

Liquid agent for the chemical destruction of soot and method of application Download PDF

Info

Publication number
EP0007862B1
EP0007862B1 EP79400514A EP79400514A EP0007862B1 EP 0007862 B1 EP0007862 B1 EP 0007862B1 EP 79400514 A EP79400514 A EP 79400514A EP 79400514 A EP79400514 A EP 79400514A EP 0007862 B1 EP0007862 B1 EP 0007862B1
Authority
EP
European Patent Office
Prior art keywords
magnesium
agent
potassium
atoms
nitrate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP79400514A
Other languages
German (de)
French (fr)
Other versions
EP0007862A1 (en
Inventor
Jean-Claude Palumbo
Jean Rousseau
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DRIVEX SA
Original Assignee
DRIVEX SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from FR7821901A external-priority patent/FR2432041A1/en
Priority claimed from FR7917117A external-priority patent/FR2460318A2/en
Application filed by DRIVEX SA filed Critical DRIVEX SA
Publication of EP0007862A1 publication Critical patent/EP0007862A1/en
Application granted granted Critical
Publication of EP0007862B1 publication Critical patent/EP0007862B1/en
Expired legal-status Critical Current

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10LFUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L10/00Use of additives to fuels or fires for particular purposes
    • C10L10/06Use of additives to fuels or fires for particular purposes for facilitating soot removal
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10LFUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L1/00Liquid carbonaceous fuels
    • C10L1/10Liquid carbonaceous fuels containing additives
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23JREMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J7/00Arrangement of devices for supplying chemicals to fire

Definitions

  • the present invention relates to the chemical sweeping of ovens and boilers of all types and flues.
  • soot designates unburnt carbon and that the term “deposits” as used below designates a mixture deposited on the surfaces and consisting of soot, fuel ash containing in particular iron sulphates and oxides of metals, corrosion products, etc.
  • Chloride-based products have been used, for example, which lower the ignition point of carbon, but which present a fire risk and above all a risk of corrosion by the hydrochloric acid which is released as a result of the reaction of chlorides with sulfuric anhydride retained in soot and coming from the sulfur which the majority of the fuels contain.
  • U.S. Patent 2,949,008 relates to a chemical agent containing a magnesium compound and an alkali metal compound and which can be applied in the form of an aqueous solution, but this agent is intended not to chemically destroy the soot, but to reduce corrosion of the soot.
  • a known chimney sweeping agent is a mixture, in powder form, of potassium nitrate in high proportion and of sulfur and charcoal in low proportion.
  • the pulverulent mixture is injected with compressed air and burned in the flame of the burner of the oven or of the boiler at a temperature above 450 ° C., the combustion of this mixture causing, with a significant release of heat, the formation of 'A complex gas, containing in particular carbon dioxide and sulfuric anhydride, and very fine solid particles consisting essentially of potassium carbonate, but also potassium sulfate and potassium oxide, among others.
  • the potassium carbonate has an effect of lowering the ignition point of the carbon of the soot and an oxidation effect of this carbon, which is destroyed from 130 ° C by transformation into carbon dioxide (it is a combustion slow catalytic), while potassium oxide partially neutralizes the acidic sulfur derivatives retained in the deposits.
  • Chimney sweeps and blowing become unnecessary and it suffices to periodically remove by suction the deposits, which are no longer made up of powdery and poorly adherent ash, containing in particular iron sulphates and metal oxides from the fuel.
  • this chimney sweeping agent presents several difficulties: in fact, the powder of said mixture melts at 140 ° C.
  • the object of the present invention is to remedy the great difficulty of applying, in practice, this chemical chimney sweeping agent.
  • This agent which is an aqueous solution of an alkali metal compound and a magnesium compound, is characterized in that the alkali metal compound is potassium acetate, CH, Co 2 K, in that the compound of magnesium is magnesium nitrate, (NO 3 ) 2 Mg ' or a mixture of magnesium nitrate and magnesium acetate, (CH, C0 2 ) 2 Mg, and in that the relative proportions of potassium and magnesium in the agent are 40 to 60 atoms of the first for 60 to 40 atoms of the second.
  • said solution can contain 56 potassium atoms for 44 magnesium atoms.
  • the proportion of water is variable, the most suitable dilution being able to be easily determined experimentally in each particular case of use.
  • the solution initially prepared and delivered to users is a saturated solution, to reduce congestion during storage and transport.
  • Alkaline silicates can optionally be added to the liquid agent in question, for example in the form of a saturated aqueous solution added to the saturated aqueous solution of the agent. Indeed, in some cases, we meet not only the soot problem, but also the problem of melting the fuel ash. This melting point is sometimes such that the ash deposits are in the form of pasty masses.
  • the addition of silicates makes it possible to raise the melting point of ash cases, therefore, to make them "dry", non-adherent and therefore easily removable, and less corrosive, when they contain corrosive substances such as vanadium. , which may be the case when they result from the combustion of fuel oil.
  • the proportion of silicates can be from 5 to 10% by weight relative to the weight of the agent.
  • the liquid chemical sweeping agent according to the invention is easy to spray into the flame of the burner of an oven or a boiler by means of compressed air, or better still by means of an electric vibrator. There is no exothermic reaction which may cause an explosion.
  • the water evaporates as soon as the solution reaches 100 ° C, a temperature which it is useless to exceed.
  • the dry extract then ignites very quickly, it is broken down into its elements, and the free potassium and magnesium ions generate, in the oxidizing atmosphere of the flame reinforced by the oxidizing nitrate ions, on the one hand, potassium oxide (K 2 0), which becomes pulverulent potassium carbonate (CO, K 2 ), in the presence of the carbon dioxide of the combustion gases to which is added that resulting from the subsequent oxidation of the soot by this carbonate, and, on the other hand, magnesium oxide (MgO) also in the pulverulent state.
  • the potassium carbonate ensures the catalytic combustion of soot present in the combustion gases and on the surfaces, in the above-mentioned manner, by lowering the ignition point of carbon and by an oxidation effect on carbon.
  • the powdery potassium carbonate which is added to the deposits, does not adhere to the walls and is easily removable.
  • magnesium oxide it neutralizes the sulfur oxidation products retained by the deposits as well as the sulfuric acid condensed in the cold areas of the furnace or boiler, whereas with the previous chemical sweeping agents, it was generally necessary to carry out an additional treatment, consisting in spraying in these cold areas very fine magnesium oxide, in particular of a size less than 10 microns, which was not an easy operation; with the new chemical sweeping agent, MgO is formed in situ. Since potassium carbonate is basic, it cooperates with MgO for the neutralizing action.
  • the magnesium sulphate and potassium sulphate formed are powdery, non-adherent, easily removable products.
  • the ratio between the number of potassium atoms and the number of nitrate ions (N03) in the present agent is 1.87, which corresponds 56 potassium atoms for 30 nitrate ions.
  • this preferred K / N03 ratio of 1.87 is to optimize the combustion of the dry extract obtained after evaporation of the water, when said agent is used.
  • NO 3 - ions If the content of NO 3 - ions is greater than 30 ions, there is a risk of formation of toxic nitrogen oxides, NO x , as well as products such as nitrites which may be found on the surfaces of the oven or the boiler and the smoke ducts, in the molten state and inactive, from where also a loss of efficiency of the agent.
  • magnesium can no longer, in this case, be present in the agent only in the form of nitrate, if one wishes to maintain the preferential ratio K / Mg of 56 atoms of the first for 44 atoms of the second.
  • the magnesium supplement is then provided in the form of magnesium acetate.
  • the improved liquid agent according to the present invention is characterized in that the magnesium compound which it contains is a mixture of magnesium nitrate, (NO,) 2 Mg, and magnesium acetate, (CH , C0 2 ) 2 Mg, in the preferred proportions of 15 molecules of nitrate for 29 molecules of acetate.
  • the subject of the invention is also the method of applying said agent, consisting in spraying it into the flame by means of an electric vibrator, which makes it possible, much better than compressed air, to control the injection.
  • an electric vibrator which makes it possible, much better than compressed air, to control the injection.
  • the latter can be either a solid fuel (charcoal, wood, shale, lignite, for example), liquid (oil), or gaseous.
  • the liquid form of the agent and its spraying ensure an optimal fine distribution and maximum efficiency of the agent.
  • the sulfuric anhydride (S0 3 ) content of the deposits is usually analyzed when does chemical sweeping; this anhydride having to be currently neutralized by magnesium oxide, account is taken of the results of said analysis to introduce magnesium nitrate and possibly magnesium acetate in greater or lesser proportions into the chemical sweeping agent considered, and the agent injection rate or the frequency of its injection are also determined by this analysis as well as, of course, by the size of the deposits.
  • the injections were periodic, with the new liquid agent, spraying in the flame can be carried out continuously and it has an anti-pollution effect continuously. atmosphere and anticorrosion of the equipment.
  • Another object of the invention is the process for the preparation of the new chemical chimney sweeping agent considered.
  • This process consists in preparing a saturated aqueous solution of potassium acetate and optionally magnesium acetate, from acetic acid and, respectively, potassium carbonate and magnesium carbonate, in stoichiometric proportions, then preparing a saturated aqueous solution of magnesium nitrate, starting from nitric acid and magnesium carbonate in stoichiometric proportions, all these preparations being carried out individually under cooling, after which the saturated solutions are mixed so that the ratio of potassium to magnesium in the mixture of 40 to 60 atoms of the first for 60 to 40 atoms of the second and diluted with water in a variable manner, at the time of use, the concentrated intermediate mixture thus obtained, the most favorable dilution being determined experimentally in each case of use of the final solution.
  • the mixing is preferably carried out so that it contains 56 post potassium atoms for 44 magnesium atoms and, when we want to obtain the optimal ratio of 1.87 between the number of potassium atoms and the number of nitrate ions, so that it contains, for 56 molecules of potassium acetate, 15 molecules of magnesium nitrate and 29 molecules of magnesium acetate.
  • silicates can be added to the solution, as indicated above.
  • potassium magnesium acetates and magnesium nitrate potassium hydroxide, KOH, and magnesia, MgO, can also be used instead of potassium carbonate and magnesium carbonate, respectively. Stoichiometric proportions of these bases and of acetic and nitric acids are also used.
  • the agent according to the invention can be prepared in the following manner: under cooling, successively and in stoichiometric proportions are poured into the total amount of water necessary to obtain a saturated solution in the desired amounts of the various constituents, acetic acid, potassium carbonate or potash necessary to form potassium acetate, magnesium carbonate or magnesia necessary to form magnesium acetate, nitric acid, magnesium carbonate or magnesia necessary to form magnesium nitrate, then diluted with water, at the time of use, the concentrated solution obtained, the most favorable dilution being determined experimentally in each case of use of the final solution.
  • the necessary cooling during the preparation of the agent can be obtained by circulating cold water in the reaction medium (for example by means of an immersed coil), or around this medium; for example, the preparation can be carried out in a lined container and a circulation of cooling water established in the liner of the container.
  • composition of the agent according to the invention is given below, but it is in no way limiting.
  • the preparation of the product can be carried out according to the method indicated above as an alternative, that is to say by successively adding and under cooling, in the 69.5 parts of water, the quantity of acetic acid necessary to form 14.5 parts of potassium acetate and 10.1 parts of magnesium acetate, the amount of potassium carbonate required to form 14.5 parts of potassium acetate, the amount of magnesium carbonate required to form 10.1 parts of magnesium acetate, the amount of nitric acid required to form 5.9 parts of magnesium nitrate, and the amount of magnesium carbonate required to form 5.9 parts of magnesium nitrate.
  • This concentrated solution will be diluted variably at the time of use and depending on the use.
  • potassium carbonate and the magnesium carbonate can be replaced, as mentioned above, by potash and magnesia.

Description

La présente invention concerne le ramonage chimique des fours et chaudières de tous types et des conduits de fumée.The present invention relates to the chemical sweeping of ovens and boilers of all types and flues.

Il est bien connu que la combustion des combustibles, solides, liquides et gazeux laisse un dépôt de carbone imbrûlé ou suie sur les surfaces intérieures des fours, chaudières et conduits de fumée et que cette suie constitue un revêtement calorifuge nuisible au bon transfert thermique et accroissant, par conséquent, la consommation d'énergie, d'où la nécessité des ramonages à la vapeur d'eau ou des soufflages à l'air comprimé. Or, ces procédés ont l'inconvénient évident de polluer l'atmosphère et ils sont donc néfastes.It is well known that the combustion of fuels, solids, liquids and gases leaves a deposit of unburnt carbon or soot on the interior surfaces of ovens, boilers and flues and that this soot constitutes a heat-insulating coating detrimental to good thermal transfer and increasing , therefore, energy consumption, hence the need for sweeping with steam or blowing with compressed air. However, these methods have the obvious disadvantage of polluting the atmosphere and they are therefore harmful.

Il convient de préciser que le terme "suie" désigne le carbone imbrûlé et que le terme "dépôts" tel qu"utilisé ci-après désigne un mélange déposé sur les surfaces et constitué de suie, de cendres du combustible contenant notamment des sulfates de fer et des oxydes de métaux, de produits de corrosion, etc.It should be specified that the term "soot" designates unburnt carbon and that the term "deposits" as used below designates a mixture deposited on the surfaces and consisting of soot, fuel ash containing in particular iron sulphates and oxides of metals, corrosion products, etc.

On a déjà proposé des agents de ramonage chimique, destinés à éviter la pollution atmosphérique. On a utilisé, par exemple, des produits à base de chlorures, qui abaissent le point d'ignition du carbone, mais qui présentent des risques d'incendie et surtout des risques de corrosion par l'acide chlorhydrique qui est libéré, par suite de la réaction des chlorures avec l'anhydride sulfurique retenu dans la suie et provenant du soufre que contiennent la plupart des combustibles.Chimney sweeping agents have already been proposed, intended to avoid atmospheric pollution. Chloride-based products have been used, for example, which lower the ignition point of carbon, but which present a fire risk and above all a risk of corrosion by the hydrochloric acid which is released as a result of the reaction of chlorides with sulfuric anhydride retained in soot and coming from the sulfur which the majority of the fuels contain.

Le brevet américain 2 949 008 concerne un agent chimique contenant un composé de magnésium et un composé de métal alcalin et pouvant être appliqué sous forme de solution aqueuse, mais cet agent est destiné non pas à détruire chimiquement la suie, mais à réduire la corrosion des parties métalliques par les cendres contenant du vanadium, qui résultent de la combustion de combustibles pétroliers résiduaires contenant du vanadium; il ne s'agit donc pas d'un agent de ramonage.U.S. Patent 2,949,008 relates to a chemical agent containing a magnesium compound and an alkali metal compound and which can be applied in the form of an aqueous solution, but this agent is intended not to chemically destroy the soot, but to reduce corrosion of the soot. metallic parts from ash containing vanadium, which result from the combustion of waste petroleum fuels containing vanadium; therefore it is not a chimney sweeper

Un agent chimique de ramonage connu est un mélange, sous forme de poudre, de nitrate de potassium en forte proportion et de soufre et de charbon de bois en faibles proportions. On injecte à l'air comprimé et fait brûler le mélange pulvérulent dans la flamme du brûleur du four ou de la chaudière à une température supérieure à 450°C, la combustion de ce mélange engendrant, avec un dégagement de chaleur important, la formation d'un gaz complexe, contenant notamment de l'anhydride carbonique et de l'anhydride sulfurique, et de particules solides très fines constituées essentiellement de carbonate de potassium, mais aussi de sulfate de potassium et d'oxyde de potassium, entre autres. Le carbonate de potassium a un effect d'abaissement du point d'ignition du carbone des suies et un effet d'oxydation de ce carbone, qui est détruit dès 130°C par transformation en gaz carbonique (il s'agit d'une combustion lente catalytique), tandis que l'oxyde de potassium neutralise partiellement les dérivés acides du soufre retenus dans les dépôts. Les ramonages et les soufflages deviennent inutiles et il suffit d'éliminer périodiquement par aspiration les dépôts, qui ne sont plus constitués que de cendres pulvérulentes et peu adhérentes, contenant notamment des sulfates de fer et les oxydes des métaux provenant du combustible. Cependant, l'utilisation convenable de cet agent chimique de ramonage présente plusieurs difficultés: en effet, la poudre dudit mélange fond à 140°C et il faut parvenir à l'injecter dans la flamme du brûleur sans qu'elle fonde, sinon, par suite du bouchage du tube d'injection, il peut se produire une explosion; il faut donc déterminer, dans chaque cas particulier, la vitesse d'injection appropriée évitant la fusion de la poudre et il faut, dans ce but, étudier la combinaison de mouvements, à laquelle est soumise la poudre injectée (mouvement linéaire de l'injection initiale et mouvement de rotation de l'air comprimé, chargé de la poudre dans la flamme du brûleur). De plus, la nécessité, en fait, d'une température de combustion de la poudre d'au moins 450°C peut limiter l'efficacité dans les foyers n'atteignant pas cette température.A known chimney sweeping agent is a mixture, in powder form, of potassium nitrate in high proportion and of sulfur and charcoal in low proportion. The pulverulent mixture is injected with compressed air and burned in the flame of the burner of the oven or of the boiler at a temperature above 450 ° C., the combustion of this mixture causing, with a significant release of heat, the formation of 'A complex gas, containing in particular carbon dioxide and sulfuric anhydride, and very fine solid particles consisting essentially of potassium carbonate, but also potassium sulfate and potassium oxide, among others. The potassium carbonate has an effect of lowering the ignition point of the carbon of the soot and an oxidation effect of this carbon, which is destroyed from 130 ° C by transformation into carbon dioxide (it is a combustion slow catalytic), while potassium oxide partially neutralizes the acidic sulfur derivatives retained in the deposits. Chimney sweeps and blowing become unnecessary and it suffices to periodically remove by suction the deposits, which are no longer made up of powdery and poorly adherent ash, containing in particular iron sulphates and metal oxides from the fuel. However, the proper use of this chimney sweeping agent presents several difficulties: in fact, the powder of said mixture melts at 140 ° C. and it is necessary to inject it into the flame of the burner without it melting, otherwise, by as a result of blockage of the injection tube, an explosion may occur; it is therefore necessary to determine, in each particular case, the appropriate injection speed avoiding the melting of the powder and it is, for this purpose, to study the combination of movements, to which the injected powder is subjected (linear movement of the injection initial and rotational movement of the compressed air, charged with powder in the burner flame). In addition, the need, in fact, for a combustion temperature of the powder of at least 450 ° C. can limit the efficiency in homes not reaching this temperature.

La présente invention a pour but de remédier à la grande difficulté d'application, en pratique, de cet agent chimique de ramonage. A cet efft, elle a pour objet un nouvel agent chimique de ramonage, qui n'est pas sous forme de poudre. Cet agent, qui est une solution aqueuse d'un composé de métal alcalin et du'un composé de magnésium est caractérisé en ce que le composé de métal alcalin est l'acétate de potassium, CH,Co2K, en ce que le composé de magnésium est le nitrate de magnésium, (NO3)2Mg' ou un mélange de nitrate de magnésium et d'acétate de magnésium, (CH,C02)2Mg, et en ce que les proportions relatives du potassium et du magnésium dans l'agent sont de 40 à 60 atomes du premier pour 60 à 40 atomes du second. A titre d'example, ladite solution peut renfermer 56 atomes de potassium pour 44 atomes de magnésium. La proportion d'eau est variable, la dilution la plus convenable pouvant être déterminée facilement expérimentalement dans chaque cas particulier d'emploi. La solution initialement préparée et livrée aux utilisateurs est une solution saturée, pour réduire l'encombrement pendant le stockage et le transport.The object of the present invention is to remedy the great difficulty of applying, in practice, this chemical chimney sweeping agent. To this end, it relates to a new chemical chimney sweeping agent, which is not in powder form. This agent, which is an aqueous solution of an alkali metal compound and a magnesium compound, is characterized in that the alkali metal compound is potassium acetate, CH, Co 2 K, in that the compound of magnesium is magnesium nitrate, (NO 3 ) 2 Mg ' or a mixture of magnesium nitrate and magnesium acetate, (CH, C0 2 ) 2 Mg, and in that the relative proportions of potassium and magnesium in the agent are 40 to 60 atoms of the first for 60 to 40 atoms of the second. By way of example, said solution can contain 56 potassium atoms for 44 magnesium atoms. The proportion of water is variable, the most suitable dilution being able to be easily determined experimentally in each particular case of use. The solution initially prepared and delivered to users is a saturated solution, to reduce congestion during storage and transport.

On peut éventuellement ajouter à l'agent liquide considéré des silicates alcalins, par exemple sous forme d'une solution aqueuse saturée ajoutée à la solution aqueuse saturée de l'agent. En effet, dans certains cas, on rencontre non seulement le problème des suies, mais aussi le problème de la fusion des cendres du combustible. Ce point de fusion est parfois tel que les dépôts de cendres se présentent sous la forme de masses pâteuses. L'addition de silicates permet d'élever le point de fusion de cas cendres, par conséquent, de les rendre "sèches", non adhérentes et par suite facilement éliminables, et moins corrosives, lorsqu'elles renferment des substances corrosives telles que le vanadium, ce qui peut être le cas lorsqu'elles résultent de la combustion du mazout.Alkaline silicates can optionally be added to the liquid agent in question, for example in the form of a saturated aqueous solution added to the saturated aqueous solution of the agent. Indeed, in some cases, we meet not only the soot problem, but also the problem of melting the fuel ash. This melting point is sometimes such that the ash deposits are in the form of pasty masses. The addition of silicates makes it possible to raise the melting point of ash cases, therefore, to make them "dry", non-adherent and therefore easily removable, and less corrosive, when they contain corrosive substances such as vanadium. , which may be the case when they result from the combustion of fuel oil.

La proportion des silicates peut être de 5 à 10% en poids par rapport au poids de l'agent.The proportion of silicates can be from 5 to 10% by weight relative to the weight of the agent.

L'agent liquide de ramonage chimique suivant l'invention est facile à pulvériser dans la flamme du brûleur d'un four ou d'une chaudière au moyen d'air comprimé, ou mieux encore au moyen d'un vibreur électrique. Il ne se produit aucune réaction exothermique susceptible de provoquer une explosion. L'eau s'évapore dès que la solution atteint 100°C, température qu'il est inutile de déprasser. L'extrait sec s'enflamme alors très rapidement, il est décomposé en ses éléments, et les ions libres potassium et magnésium engendrent, dans l'atmosphère oxydante de la flamme renforcée par les ions nitrate oxydants, d'une part, de l'oxyde de potassium (K20), qui se transforme en carbonate de potassium (CO,K2) pulvérulent, en présence du gaz carbonique des gaz de combustion auquel s'ajoute celui provenant de l'oxydation subséquente des suies par ce carbonate, et, d'autre part, de l'oxyde de magnésium (MgO) également à l'état pulvérulent. Le carbonate de potassium assure la combustion catalytique de suies présentes dans les gaz de combustion et sur les surfaces, de la manière susindiquée, par abaissement du point d'ignition du carbone et par un effet d'oxydation du carbone. D'autre part, le carbonate de potassium pulvérulent, qui s'ajoute aux dépôts, n'adhère pas aux parois et est facilement éliminable. Quant à l'oxyde de magnésium, il neutralise les produits d'oxydation du soufre retenus par les dépôts ainsi que l'acide sulfurique condensé dans les zones froides du four ou de la chaudière, alors qu'avec les agents de ramonage chimiques antérieurs, il était généralement nécessaire d'effectuer un traitement complémentaire, consistant à pulvériser dans ces zones froides de l'oxyde de magnésium très fin, en particulier d'une taille inférieure à 10 microns, ce qui n'était pas une opération facile; avec le nouvel agent de ramonage chimique, MgO est formé in situ. Le carbonate de potassium étant basique, il coopère avec MgO pour l'action de neutralisation. Le sulfate de magnésium et le sulfate de potassium formés sont des produits pulvérulents, non adhérents, facilement éliminables.The liquid chemical sweeping agent according to the invention is easy to spray into the flame of the burner of an oven or a boiler by means of compressed air, or better still by means of an electric vibrator. There is no exothermic reaction which may cause an explosion. The water evaporates as soon as the solution reaches 100 ° C, a temperature which it is useless to exceed. The dry extract then ignites very quickly, it is broken down into its elements, and the free potassium and magnesium ions generate, in the oxidizing atmosphere of the flame reinforced by the oxidizing nitrate ions, on the one hand, potassium oxide (K 2 0), which becomes pulverulent potassium carbonate (CO, K 2 ), in the presence of the carbon dioxide of the combustion gases to which is added that resulting from the subsequent oxidation of the soot by this carbonate, and, on the other hand, magnesium oxide (MgO) also in the pulverulent state. The potassium carbonate ensures the catalytic combustion of soot present in the combustion gases and on the surfaces, in the above-mentioned manner, by lowering the ignition point of carbon and by an oxidation effect on carbon. On the other hand, the powdery potassium carbonate, which is added to the deposits, does not adhere to the walls and is easily removable. As for magnesium oxide, it neutralizes the sulfur oxidation products retained by the deposits as well as the sulfuric acid condensed in the cold areas of the furnace or boiler, whereas with the previous chemical sweeping agents, it was generally necessary to carry out an additional treatment, consisting in spraying in these cold areas very fine magnesium oxide, in particular of a size less than 10 microns, which was not an easy operation; with the new chemical sweeping agent, MgO is formed in situ. Since potassium carbonate is basic, it cooperates with MgO for the neutralizing action. The magnesium sulphate and potassium sulphate formed are powdery, non-adherent, easily removable products.

L'intérêt de l'association de la'acétate de potassium et du nitrate de magnésium pour l'élimination de suies et la neutralisation de l'acidité corrosive dans le foyer et dans le conduits de fumée est donc évident.The advantage of the association of potassium acetate and magnesium nitrate for the elimination of soot and the neutralization of corrosive acidity in the hearth and in the flues is therefore obvious.

Ce nouvel agent est ainsi applicable sans danger ni difficultés particuilières et il est d'une grande efficacité. De plus, les constituants choisis sont très solubles dans l'eau, ce qui permet de préparer une solution concentrée, dont le faible volume est avantageux pour le stockage et le transport.This new agent is thus applicable without danger or particular difficulties and it is very effective. In addition, the constituents chosen are very soluble in water, which makes it possible to prepare a concentrated solution, the small volume of which is advantageous for storage and transport.

On a aussi constaté, suivant la présente invention, qu'il est particulièrement avantageux que le rapport entre le nombre d'atomes de potassium et le nombre d'ions nitrate (N03 ) dans le présent agent soit de 1,87, ce qui correspond à 56 atomes de potassium pour 30 ions nitrate.It has also been found, according to the present invention, that it is particularly advantageous that the ratio between the number of potassium atoms and the number of nitrate ions (N03) in the present agent is 1.87, which corresponds 56 potassium atoms for 30 nitrate ions.

Ce rapport préféré K/N03 de 1,87 a pour but de rendre optimale la combustion de l'extrait sec obtenu après évaporation de l'eau, lors de l'utilisation dudit agent.The purpose of this preferred K / N03 ratio of 1.87 is to optimize the combustion of the dry extract obtained after evaporation of the water, when said agent is used.

Si la teneur en ions NO3 - est inférieure à 30 ions, la combustion de l'extrait sec est insuffisante pour permettre la décomposition rapide de celui-ci en K20, K2CO3, MgO, O2 et N2, d'où une perte d'efficacité de l'agent.If the content of NO 3 - ions is less than 30 ions, the combustion of the dry extract is insufficient to allow its rapid decomposition into K 2 0, K 2 CO 3 , MgO, O2 and N 2 , d 'where a loss of effectiveness of the agent.

Si la teneur en ions NO3 - est supérieure à 30 ions, il y a un risque de formation d'oxydes d'azote toxiques, NOx, ainsi que de produits tels que des nitrites pouvant se retrouver sur les surfaces du four ou de la chaudière et des conduits de fumée, à l'état fondu et inactifs, d'où également une perte d'efficacité de l'agent.If the content of NO 3 - ions is greater than 30 ions, there is a risk of formation of toxic nitrogen oxides, NO x , as well as products such as nitrites which may be found on the surfaces of the oven or the boiler and the smoke ducts, in the molten state and inactive, from where also a loss of efficiency of the agent.

Compte tenu du rapport préférentiel K/N03 de 56 atomes du premier pour 30 ions du second, le magnésium ne peut plus, dans ce cas, être présent dans l'agent uniquement sous forme de nitrate, si l'on veut maintenir le rapport préférentiel K/Mg de 56 atomes du premier pour 44 atomes du second. Le complément de magnésium est alors apporté sous forme d'acétate de magnésium.Taking into account the preferential ratio K / N03 of 56 atoms of the first for 30 ions of the second, magnesium can no longer, in this case, be present in the agent only in the form of nitrate, if one wishes to maintain the preferential ratio K / Mg of 56 atoms of the first for 44 atoms of the second. The magnesium supplement is then provided in the form of magnesium acetate.

Dans ces conditions, l'agent liquide perfectionné suivant la présente invention est caractérisé en ce que le composé de magnésium qu'il renferme est un mélange de nitrate de magnésium, (NO,)2Mg, et d'acétate de magnésium, (CH,C02)2Mg, dans les proportions préférées de 15 molécules de nitrate pour 29 molécules d'acétate.Under these conditions, the improved liquid agent according to the present invention is characterized in that the magnesium compound which it contains is a mixture of magnesium nitrate, (NO,) 2 Mg, and magnesium acetate, (CH , C0 2 ) 2 Mg, in the preferred proportions of 15 molecules of nitrate for 29 molecules of acetate.

L'invention a aussi pour objet le procédé d'application dudit agent consistant à le pulvériser dans la flamme au moyen d'un vibreuer électrique, qui permet, beaucoup mieux que l'air comprimé, de contrôler l'injection. On peut alors plus aisément programmer les injections en fonction du temps et les asservir au débit du combustible. Ce dernier peut être indifféremment un combustible solide (charbôn, bois, schiste, lignite, par exemple), liquide (mazout), ou gazeux. La forme liquide de l'agent et sa pulvérisation assurent une répartition fine optimale et une efficacité maximale de l'agent.The subject of the invention is also the method of applying said agent, consisting in spraying it into the flame by means of an electric vibrator, which makes it possible, much better than compressed air, to control the injection. We can then more easily program the injections as a function of time and control them according to the fuel flow rate. The latter can be either a solid fuel (charcoal, wood, shale, lignite, for example), liquid (oil), or gaseous. The liquid form of the agent and its spraying ensure an optimal fine distribution and maximum efficiency of the agent.

On analyse habituellement la teneur en anhydride sulfurique (S03) des dépôts, lorsqu'on fait du ramonage chimique; cet anhydride devant être présentement neutralisé par l'oxyde de magnésium, on tient compte des résultats de ladite analyse pour introduire du nitrate de magnésium et éventuellement de l'acétate de magnésium en plus ou moins grandes proportions dans l'agent de ramonage chimique considéré, et le débit d'injection de l'agent ou la fréquence de son injection sont égalment déterminés par cette analyse ainsi que, bien entendu, par l'importance des dépôts. Alors qu'avec l'agent antérieur à base de nitrate depotassium sous forme de poudre, les injections étaient périodiques, avec le nouvel agent liquide, la pulvérisation dans la flamme peut être effectuée en continu et elle a en continu un effet antipollution de l'atmosphère et anticorrosion de l'appareillage.The sulfuric anhydride (S0 3 ) content of the deposits is usually analyzed when does chemical sweeping; this anhydride having to be currently neutralized by magnesium oxide, account is taken of the results of said analysis to introduce magnesium nitrate and possibly magnesium acetate in greater or lesser proportions into the chemical sweeping agent considered, and the agent injection rate or the frequency of its injection are also determined by this analysis as well as, of course, by the size of the deposits. Whereas with the previous agent based on potassium nitrate in powder form, the injections were periodic, with the new liquid agent, spraying in the flame can be carried out continuously and it has an anti-pollution effect continuously. atmosphere and anticorrosion of the equipment.

Un autre objet de l'invention est le procédé de préparation du nouvel agent de ramonage chimique considéré.Another object of the invention is the process for the preparation of the new chemical chimney sweeping agent considered.

Ce procédé consiste à préparer une solution aqueuse saturée d'acétate de potassium et éventuellement d'acétate de magnésium, à partir d'acide acétique et, respectivement, de carbonate de potassium et de carbonate de magnésium, en proportions stoechiométriques, puis à préparer une solution aqueuse saturée de nitrate de magnésium, à partir d'acide nitrique et de carbonate de magnésium en proportions stoechiométriques, toutes ces préparations étant effectuées isolément sous refroidissement, après quoi on mélange les solutions saturées de façon que le rapport du potassium au magnésium dans le mélange soit de 40 à 60 atomes du premier pour 60 à 40 atomes du second et l'on dilue à l'eau d'une façon variable, au moment de l'emploi, le mélange intermédiaire concentré ainsi obtenu, la dilution la plus favourable étant déterminée expérimentalement dans chaque cas d'utilisation de la solution finale.This process consists in preparing a saturated aqueous solution of potassium acetate and optionally magnesium acetate, from acetic acid and, respectively, potassium carbonate and magnesium carbonate, in stoichiometric proportions, then preparing a saturated aqueous solution of magnesium nitrate, starting from nitric acid and magnesium carbonate in stoichiometric proportions, all these preparations being carried out individually under cooling, after which the saturated solutions are mixed so that the ratio of potassium to magnesium in the mixture of 40 to 60 atoms of the first for 60 to 40 atoms of the second and diluted with water in a variable manner, at the time of use, the concentrated intermediate mixture thus obtained, the most favorable dilution being determined experimentally in each case of use of the final solution.

On effectue préféreniellement le mélange de façon qu'il contienne 56 atomes de postassium pour 44 atomes de magnésium et, lorsqu'on veut obtenir le rapport optimal de 1,87 entre le nombre d'atomes de potassium et le nombre d'ions nitrate, de façon qu'il contienne, pour 56 molécules d'acétate de potassium, 15 molécules de nitrate de magnésium et 29 molécules d'acétate de magnésium.The mixing is preferably carried out so that it contains 56 post potassium atoms for 44 magnesium atoms and, when we want to obtain the optimal ratio of 1.87 between the number of potassium atoms and the number of nitrate ions, so that it contains, for 56 molecules of potassium acetate, 15 molecules of magnesium nitrate and 29 molecules of magnesium acetate.

On peut éventuellement ajouter des silicates à la solution, comme susindiqué.Optionally, silicates can be added to the solution, as indicated above.

Pour préparer les acétates de potassium et de magnésium et le nitrate de magnésium, on peut aussi employer la potasse, KOH, et la magnésie, MgO, à la place, respectivement, du carbonate de potassium et du carbonate de magnésium. On emploie également des proportions stoechiométriques de ces bases et des acides acétique et nitrique.To prepare potassium magnesium acetates and magnesium nitrate, potassium hydroxide, KOH, and magnesia, MgO, can also be used instead of potassium carbonate and magnesium carbonate, respectively. Stoichiometric proportions of these bases and of acetic and nitric acids are also used.

En variante, on peut préparer l'agent suivant l'invention de la façon suivante: sous refroidissement, on verse successivement et en proportions stoechiométriques, dans la quantité totale d'eau nécessaire pour obtenir une solution saturée en les quantités voulues des divers constituants, l'acide acétique, le carbonate de potassium ou la potasse nécessaire pour former l'acétate de potassium, le carbonate de magnésium ou la magnésie nécessaire pour former l'acétate de magnésium, l'acide nitrique, le carbonate de magnésium ou la magnésie nécessaire pour former le nitrate de magnésium, puis on dilue à l'eau, au moment de l'emploi, la solution concentrée obtenue, la dilution la plus favorable étant déterminée expérimentalement dans chaque cas d'utilisation de la solution finale.As a variant, the agent according to the invention can be prepared in the following manner: under cooling, successively and in stoichiometric proportions are poured into the total amount of water necessary to obtain a saturated solution in the desired amounts of the various constituents, acetic acid, potassium carbonate or potash necessary to form potassium acetate, magnesium carbonate or magnesia necessary to form magnesium acetate, nitric acid, magnesium carbonate or magnesia necessary to form magnesium nitrate, then diluted with water, at the time of use, the concentrated solution obtained, the most favorable dilution being determined experimentally in each case of use of the final solution.

Le refroidissement nécessaire au cours de la préparation de l'agent peut être obtenu par une circulation d'eau froide dans le milieu réactionnel (par exemple au moyen d'un serpentin immergé), ou autour de ce milieu; par exemple, on peut procéder à la préparation dans un récipient chemisé et établir une circulation d'eau de refroidissement dans la chemise du récipient.The necessary cooling during the preparation of the agent can be obtained by circulating cold water in the reaction medium (for example by means of an immersed coil), or around this medium; for example, the preparation can be carried out in a lined container and a circulation of cooling water established in the liner of the container.

Un exemple préféré de composition de l'agent suivant l'invention est donné ci-après, mais il n'est aucunement limitatif.A preferred example of composition of the agent according to the invention is given below, but it is in no way limiting.

Exemple:Example:

Composition de l'agent, sous forme de solution aqueuse saturée (pour 100 parties en poids):

  • 14,5 parties en poids d'acétate de potassium 5,9 parties en poids de nitrate de magnésium
  • 10,1 parties en poids d'acétate de magnésium
  • 69,5 parties en poids d'eau.
Composition of the agent, in the form of a saturated aqueous solution (per 100 parts by weight):
  • 14.5 parts by weight of potassium acetate 5.9 parts by weight of magnesium nitrate
  • 10.1 parts by weight of magnesium acetate
  • 69.5 parts by weight of water.

La préparation du produit peut être effectuée selon le procédé indiqué ci-dessus à titre de variante, c'est-à-dire en ajoutant successivement et sous refroidissement, dans les 69,5 parties d'eau, la quantité d'acide acétique nécessaire pour former 14,5 parties d'acétate de potassium et 10,1 parties d'acétate de magnésium, la quantité de carbonate de potassium nécessaire pour former 14,5 parties d'acétate de potassium, la quantité de carbonate de magnésium nécessaire pour former 10,1 parties d'acétate de magnésium, la quantité d'acide nitrique nécessaire pour former 5,9 parties de nitrate de magnésium, et la quantité de carbonate de magnésium nécessaire pour former 5,9 parties de nitrate de magnésium.The preparation of the product can be carried out according to the method indicated above as an alternative, that is to say by successively adding and under cooling, in the 69.5 parts of water, the quantity of acetic acid necessary to form 14.5 parts of potassium acetate and 10.1 parts of magnesium acetate, the amount of potassium carbonate required to form 14.5 parts of potassium acetate, the amount of magnesium carbonate required to form 10.1 parts of magnesium acetate, the amount of nitric acid required to form 5.9 parts of magnesium nitrate, and the amount of magnesium carbonate required to form 5.9 parts of magnesium nitrate.

Cette solution concentrée sera diluée de façon variable au moment de l'emploi et en fonction de l'utilisation.This concentrated solution will be diluted variably at the time of use and depending on the use.

Bien entendu, la carbonate de potassium et le carbonate de magnésium peuvent être remplacés, comme susindiqué, par de la potasse et de la magnésie.Of course, the potassium carbonate and the magnesium carbonate can be replaced, as mentioned above, by potash and magnesia.

Claims (9)

1. A liquid agent for the chemical decomposition of soot, having the form of an aqueous solution of an alkali metal compound and a magnesium compound, characterised in that the alkali metal compound is potassium acetate, CH3C02K, and in that the magnesium compound is magnesium nitrate, Mg(N03)2, or a mixture of magnesium nitrate and magnesium acetate, (CH3CO2)2Mg, and in that the relative proportions of the potassium and the magnesium in the agent are 40 to 60 atoms of the former to 60 to 40 atoms of the latter.
2. A liquid agent as claimed in claim '1, characterised in that the relative proportions of the potassium and the magnesium in the agent are 56 atoms of the former to 44 atoms of the latter.
3. An agent as claimed in claim 1, characterised in that the magnesium compound is a mixture of magnesium nitrate and magnesium acetate and in that the relationship between the number of potassium atoms and the number of nitrate ions is 1.87, which corresponds to 56 atoms of potassium to 30 nitrate ions.
4. An agent as claimed in claim 3, characterised in that the K/Mg ratio is 56 atoms of potassium to 44 atoms of magnesium, and in that it contains 15 magnesium nitrate molecules and 29 magnesium acetate molecules to 56 potassium acetate molecules.
5. An agent as claimed in any one of claims 1 to 4, characterised in that it also contains alkali silicates.
6. An agent as claimed in claim 5, characterised in that the proportion of silicates is 5 to 10% by weight with respect to the weight of the agent.
7. An agent as claimed in any one of cfaims 1 to 6, having the form of a saturated aqueous solution, characterised in that it contains, for 69.5 parts by weight of water, 14.5 parts by weight of potassium acetate, 5.9 parts by weight of magnesium nitrate and 10.1 parts by weight of magnesium acetate.
8. A method of application of the agent as claimed in any one of claims 1 to 7, characterised in that the agent is sprayed in the flame of the burner of an oven or a boiler by means of an electrical vibrator.
9. The application of the liquid agent as claimed in any one of claims 1 to 7 to the chemical decomposition of soot.
EP79400514A 1978-07-25 1979-07-20 Liquid agent for the chemical destruction of soot and method of application Expired EP0007862B1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
FR7821901A FR2432041A1 (en) 1978-07-25 1978-07-25 Soln. for destroying soot in chimneys - contg. potassium acetate and magnesium nitrate, and opt. magnesium acetate
FR7821901 1978-07-25
FR7917117 1979-07-02
FR7917117A FR2460318A2 (en) 1979-07-02 1979-07-02 Soln. for destroying soot in chimneys - contg. potassium acetate and magnesium nitrate, and opt. magnesium acetate

Publications (2)

Publication Number Publication Date
EP0007862A1 EP0007862A1 (en) 1980-02-06
EP0007862B1 true EP0007862B1 (en) 1982-01-27

Family

ID=26220685

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79400514A Expired EP0007862B1 (en) 1978-07-25 1979-07-20 Liquid agent for the chemical destruction of soot and method of application

Country Status (4)

Country Link
EP (1) EP0007862B1 (en)
DE (1) DE2961969D1 (en)
IT (1) IT1121017B (en)
LU (1) LU81539A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE8006781L (en) * 1980-06-16 1981-12-17 Peter M Scocca PRESENT INVENTION ALL OVER THE ENVIRONMENT AREA AND SPECIFIC REDUCTION OF SULFUR DIOXIDE AND SULFUR TRIOXIDE EMISSIONS COGASES FROM COMBUSTION
FR2585360B1 (en) * 1985-07-29 1987-11-20 Rosenbluth Germain METHOD FOR REDUCING COMBUSTION IMBRULES AND AGENT FOR IMPLEMENTING SAME

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2949008A (en) * 1958-01-29 1960-08-16 Gulf Research Development Co Residual fuels
FR1326720A (en) * 1962-05-11 1963-05-10 Maxwell Chemicals Pty Ltd Method and preparation for the treatment of foci
GB1378882A (en) * 1972-05-16 1974-12-27 Polar Chemicals Ltd Method for the removal of soot and other deposits formed as a result of the combustion of gaseous liquid and solid fuels
DD112660A1 (en) * 1973-06-26 1975-04-20

Also Published As

Publication number Publication date
LU81539A1 (en) 1980-02-14
EP0007862A1 (en) 1980-02-06
DE2961969D1 (en) 1982-03-11
IT7968534A0 (en) 1979-07-24
IT1121017B (en) 1986-03-26

Similar Documents

Publication Publication Date Title
US3837820A (en) Combustion control by additives introduced in both hot and cold zones
FR2571429A1 (en) PROCESS FOR REMOVING THE SOOT DEPOSITED ON AN EXHAUST GAS FILTER OF AN INTERNAL COMBUSTION ENGINE AND ELEMENTS FOR THE EXECUTION OF SAID METHOD
KR940006401B1 (en) Sulfur-sorbent promoter for use in a process for the in-situ production of a sorbent-oxide aerosol
KR101572562B1 (en) process of manufacturing
JPH10506981A (en) Treatment of municipal waste and other waste
LU85228A1 (en) PROCESS FOR THE FIXING OF SULFUR COMPOUNDS WHICH FORM AS REACTION PRODUCTS ON THE COMBUSTION OF SULFUR-CONTAINING FUELS IN A FIREPLACE, BY ADDITION OF ADDITIVES, AND ADDITIVES FOR THE IMPLEMENTATION OF THIS PROCESS
US4235585A (en) Process and composition for neutralization of acidic combustion products and for boiler cleaning
EP0007862B1 (en) Liquid agent for the chemical destruction of soot and method of application
EP0270719B1 (en) Process for reducing unburned combustion particles, and agent for carrying out the process
EP0058086B1 (en) Method for the prevention of deposits on or the removal of deposits from heating and ancillary surfaces
FR2698156A1 (en) A method of heat treating an effluent comprising polluting organic material or an inorganic compound.
EP1528318B1 (en) Method of cleaning heat exchange surfaces in operating furnaces
JPS60502157A (en) Aqueous carbonaceous fuel composition
CN102876423A (en) Novel coal-saving combustion improver
RU2674011C1 (en) Modifier for burning fuel
Somasundaram et al. Suppression of soot in the combustion of residual furnace oil using organometallic additives
KR100664974B1 (en) Combusting Composition of Accelerator for Scale Environmental Contaminant Reduction/Prohibition
KR0151991B1 (en) Fuel using iron and steel wastes for winnower of blast furnace
JPS5822510B2 (en) Treatment method for sulfur-containing fuel
JP2682731B2 (en) Operation method of flash furnace
RU2086023C1 (en) Method for combustion of solid radioactive wastes incorporating chlorine containing polymeric materials and biological objects
RU2061772C1 (en) Method of obtaining metallic stannum
BE1006837A6 (en) Method for direct steel production from iron-based solids
JPS6234687B2 (en)
US639859A (en) Manufacture of soot-killers.

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE GB NL SE

17P Request for examination filed
GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): DE GB NL SE

REF Corresponds to:

Ref document number: 2961969

Country of ref document: DE

Date of ref document: 19820311

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19840630

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19840816

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19850731

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19860721

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19870201

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19870401

GBPC Gb: european patent ceased through non-payment of renewal fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19881118

EUG Se: european patent has lapsed

Ref document number: 79400514.0

Effective date: 19870518

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT