MXPA99006498A - Temporary idling of a polymerization reaction - Google Patents

Abstract

Disclosed is a method for idling a polymerization reaction. The method injects a sufficient amount of deactivating agent to deactivate the catalyst while allowing the reaction to bere-established simply by adding fresh catalyst. The idling method allows for maintaining polymerization reaction conditions during a shutdown and significantly reduces the amount of time associated with re-establishing polymerization reaction conditions.

Description

TEMPORARY DETENTION OF A POLYMERIZATION REACTION DESCRIPTION OF THE INVENTION This Application claims the benefit under 35 U.S.C. 119 (e) of Provisional Application Serial No. 60 / 034,488, filed on January 13, 1997 and incorporated herein. The present invention relates to a process for stopping a polymerization reaction by the addition of a deactivating catalyst. It is well known that polymers can be produced by polymerization of olefin in a fluidized bed gas phase reactor. Typically, a gaseous mixture containing the olefins that are polymerized up through the reactor is passed, and the newly formed polymer particles are maintained in a fluidized state. The gas mixture leaves the top of the reactor and is recycled back to the bottom of the reactor by a compressor. The heat absorbed by the gas mixture is eliminated during the polymerization by heat exchangers. Examples of a fluid bed polyolefin process are described in U.S. Patent No. 4,882,400 and U.S. Patent No. 5,332,706. Numerous configurations and modifications are known. It is generally not desirable to stop a polymerization reaction. However, sometimes there are primordial reasons to stop such a process. For example, during the commercial operation of a gas phase polymerization process, cases that pose a significant risk to the continuous operation of the fluidized bed reactor may be increased. For example, if the compressor used to cool the gas and recycle circuit fails, due to electrical or mechanical failure, the cooling in the bed is lost and the exothermic reaction increases the temperature of the cylinder to sinter temperatures in an exhaust mode. , as described in U.S. Patent No. 4,547,555 (note, for example, column 1, lines 66-68). This circumstance justifies an emergency stop of the reactor. In addition, the continuous operation of a fluidized bed reactor is often endangered by operational problems. For example, U.S. Patent No. 4,306,044 discloses the importance of rapidly reducing the reaction rate during an exhaust reaction (e.g., column 1, lines 15-30). Exhaust reactions in fluidized bed reactors can result in melting the polymer into large agglomerated pieces that can be very difficult to remove. Another potential risk for the continuous operation of a fluidized bed reactor is the mechanical problem that may arise with the polymer extraction system. The extraction system removes the polymer from the reactor at a rate equal to the production of the polymer in the reactor, such that the level of the bed of the fluidized bed is maintained at a constant level. During a failure of the extraction system, the polyethylene powder can not be removed from the reactor. Since polymer is not removed from the reactor, the level of the bed in the reactor can rise high enough for the bed to be transferred to the recirculation line of the gas circuit. The transfer represents serious risks to the operation and life of the heat exchangers and the compressor in the recirculated gas circuit. Also, reactor transitions present a problem. The reactor transitions are programmed discontinuous operations of the reactor. A fluidized bed reactor undergoes transitions to change the polymerization reaction conditions in order to produce different products with different properties. In order to effect an effective transition of the operating conditions of the different objective reactor, it is preferable that the active catalyst sites existing in the reactor be deactivated. By deactivating active catalyst sites, the production of transition material is reduced. Bringing the system back to full operation is time consuming. Several strategies are known to stop a reactor. For example, the catalyst or reagent feed can be stopped. However, stopping the feeds to the reaction process will not stop the polymerization immediately if all the other parameters of the process are kept constant, such as temperature, pressure, gaseous composition of the reactor, gas velocity of the reactor, etc., since there is still active catalyst and reactants in the reactor. Such deactivation can last for a considerable amount of time. Changing process parameters, such as reactor venting, can be an effective method, but it takes time to restore the proper reactor conditions and is economically wasteful. It is also known to provide a "death" agent, that is, to deactivate the catalyst by adding a catalyst poison. United States Patent no. 4,306,044 discloses a carbon dioxide kill system which is used to kill active catalyst sites in the reactor by injecting carbon dioxide in an amount of five times the total effective catalyst system (on a molar basis; note, for example, column 6, lines 47-49). However, this method requires a significant amount of time to vent the excess poison gas and restore the polymerization reaction conditions and fails to provide an economical solution. Also U.S. Patent No. 4,834,947 describes the introduction of a carbon oxide gas (CO and C02) and venting the gas from the top of the reactor (note, for example, column 3, lines 14-19). This method also requires a significant amount of time to restore the polymerization reaction conditions and requires the replacement of expensive hydrocarbons lost from the reactor vent. In addition, U.S. Patent No. 5,270,408 (note, for example, column 7, lines 28-30 and column 7, lines 59-63) describes a method of death that also requires the replacement of expensive hydrocarbons lost from the venting of the contents of the reactor. As discussed above, there are remedies that quickly kill active catalyst sites in a reactor, but suffer from several disadvantages, such as that they are too slow to deactivate the system, they are non-economic since they lose reactor contents, and / or require a significant amount of time loss to restore reactor conditions. Accordingly, there is a need to temporarily stop a reactor in such a way that the reaction is suppressed while still maintaining the reaction conditions in the reactor such that the polymerization can begin when desired. The process according to the present invention involves a method for temporarily stopping a polymerization process by injecting in the reaction medium a predetermined amount of detention agent of such last that only currently active catalyst sites are deactivated and therefore not present free detention agent in the reactor. With deactivated active catalyst sites, the gaseous polymerization, temperature and reactor pressure compositions can be maintained under objective conditions or adjusted to fairly revised target conditions while the polymerization is in a stop mode. The reaction can then be restored immediately when desired, since the gaseous composition of the reaction, temperature, pressure, fluidization of the bed, etc., are controlled under the objective conditions. The process relates more particularly to the stopping of the fluidized gas phase reactor process. Thus, it is an object of the present invention to provide a method for immediately stopping a continuous polymerization process by introducing a catalyst deactivator, without the requirement of altering the temperature, pressure or fluidization conditions of the bed and without venting. It is another object of the invention to provide a method for immediately re-establishing a continuous polymerization process by simply introducing fresh catalyst and / or catalysts into the reactor, thereby eliminating the standstill time associated with the reestablishment of reactor conditions.

These and other objects, features and advantages of the present invention will become apparent as soon as reference is made to the following drawing, detailed description, preferred embodiments, and specific examples. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a useful arrangement of a fluid bed polyolefin process. In the process according to the present invention, a stopping agent is added to the reactor to reduce the reaction rate very quickly or to stop the reaction together with deactivation of the catalyst and / or cocatalyst. "Detention agent" as used herein means a catalyst poison, catalyst deactivator, or death agent, as these last three terms are known per se in the art. The terms are used interchangeably herein unless specifically indicated otherwise. More particularly, the stop agent is added to the process in a controlled manner such that only currently active catalyst sites are deactivated. It is not necessary to alter any other process conditions, although it is preferred that the fresh catalyst feed be reduced or discontinued, depending on how much standing time is desired. The reactor parameters can be adjusted in the case of a reactor transition. This invention has the advantages of allowing the reaction to be restored immediately when desired since the gaseous reaction composition, temperature and pressure are controlled under the objective conditions while maintaining the polymerization in a stop mode. Temporary arrest of the reactor is obtained without modifying the operating conditions of the normal polymerization reactor. By "temporary stopping of the reactor" or "temporary stopping of the reaction" is meant that the reaction occurring in the reactor is slowly reduced to the degree necessary to cure a desired problem or for reactor transition, such as for the reasons discussed above in the introduction. In some cases it may be desirable to stop the reaction only to a small degree, for example only about 50% of the ratio, but more preferably the reaction is stopped at least 85% of the normal production rate, even more preferably it is stopped. % (that is, at a 2% proportion of the normal proportion of production). Ideally, the 100% reaction is stopped, but it should be indicated that at least one of the critical aspects of the present invention is that no more than 100% of the arresting agent is added, since it is desired that the reaction be restored immediately when is desired The presence of excess detention agent will not allow this immediate restoration. Therefore, in the present invention it has been discovered that, as a practical matter to ensure that an excess of arresting agent is not added, the arresting agent is added in less than the stoichiometric amount required to deactivate the active sites of the catalyst . Further, in the present invention it has been found that, as a practical matter, an absolute stop of the reactor to cure the reactor problem or to make the reactor transition is generally not necessary. As mentioned, the reaction is generally added to the degree of approximately 50% to 99% (ie, the ratio is now 50% to 1% of the original ratio). The stopping can be achieved simply by addition of the stopping agent and, in processes including continuous addition of the fresh catalyst, stopping the addition of the fresh catalyst. The phrase "simply by adding the fresh catalyst" means that none of the other parameters of the process need to be changed, for example temperature and pressure. Of course, after the desired reduction in the process is reached, it may be desirable to change such parameters, for example, in the case of reactor transitions. The present process allows the reactor to be stopped maintaining the pressure of the reactor, fluidization of the bed, and without venting the contents of the reactor. In the case where it is desirable to change reactor conditions, such as during reactor transitions, the process according to the present invention allows a more efficient means to do so, ie, stopping the reactor. The effective reduction of the reaction achieved by the present invention varies depending on the level of the fluidized bed, the concentration of the active catalyst in the reactor, and the amount of the arresting agent added. The reduction of the reaction is from 50% to approximately 99%, preferably above 85% and more preferably reaches 98%. Generally, the reactor is stopped in such a way that there is a substantial reduction in the reaction. By "substantial reduction" it is understood that there is less than 100% arrest, but sufficient to cure the problem or provide the reactor transitions. This compares with complete stopping in other methods of reactor death, as discussed above. For example, the degree of polymerization reduction is observed by a gas temperature differential over the inlet and outlet of the reactor 9 (referred to as "reactor bed temperature differential"), which in the present invention is approximately 3.6 ° F (2 ° C). The amount of the arresting agent required to deactivate the active catalyst to the desired state of inactivity is based primarily on the amount of the catalyst (and cocatalyst, if present), more specifically, the amount of the active catalyst (eg, the transition metal). in the case of a polymerization catalyzed by transition metal) and cocatalyst (eg, trialkylaluminum), if present, existing in the process and to the degree to which activation is desired. A fraction of the stoichiometric amount of the arresting agent is added based on the mole ratio of the arresting agent to moles of the transition metal present in the process. Different catalysts require different proportions, but in each case the molar ratio of the arresting agent to transition metal is less than the stoichiometric amount. In addition, different arresting agents can provide different levels of reaction suppression based on the effects of the arresting agent on the active catalyst sites within the reactor. The ordinary technician, in possession of the present description, can determine the appropriate arresting agent and the amount of the arresting agent to add to a specific reaction, without prolonged experimentation. The process according to the present invention can be achieved for temporary stopping of the reactor without significantly modifying the polymerization conditions in the reactor by addition of the appropriate stopping agent. Preferred arresting agents for a typical olefin polymerization using a fluid bed reactor are Lewis bases, such as carbon dioxide, carbon monoxide, water, oxygen, and Lewis base mixtures, more preferably carbon monoxide, dioxide carbon or a mixture thereof. A specific example of the invention will now be explained in detail with reference to a particular fluidized bed process, but it will be understood that it is more broadly applicable to any reaction using a catalyst, cocatalyst, or other activator which can be deactivated.

It is more particularly applicable to supported catalysts and also to homogeneous catalyst systems, and can be used in a gas phase, liquid phase, suspension phase and the like. In the preferred embodiment of the invention, the process of stopping a reaction involves the continuous polymerization of olefins in a fluidized bed reactor. With reference to Figure 1, a conventional fluidized bed reaction system for polymerizing olefins is illustrated. The reactor 9 consists of a reaction zone 10 and a gas velocity reaction zone 2. The reaction zone 10 contains the fluidized bed of broad polymer particles and a smaller amount of catalyst which is fluidized by gas flow comprising of accumulation stream 12 and recirculating gas to the reaction zone. In order to maintain a viable fluidized bed, the proportion of gaseous mass flow through the bed is normally maintained above the minimum flow required for fluidization, and preferably from about 1.5 to about 10 times Gmf and more preferably about 3 to 6 times Gmf. Gmf is used in the accepted way as the abbreviation for the minimum gaseous flow required to achieve fluidization, C.Y. Wen and Y.H. Yu, "Mechanics of Fluidization", Chemical Engineering Progress Symposium Series, Vol. 62, p. 100-101 (1966). The appropriate catalyst used in the fluidized bed in the reactor is preferably injected by stream 7 with the use of an inert gas, such as nitrogen. The concentration of the catalyst in the bed is substantially equal to the concentration of the catalyst in the product, for example in the order of about 0.005 to 0.5 percent of the bed volume (0.0001-0.00001% by weight) depending on the productivity of the particular catalyst In use. The accumulation monomers, stream 12, are fed into the circuit in a ratio approximately equal to the proportion in which the polymer product, stream 8, is withdrawn from the reactor. The accumulation gas composition is determined by gas analyzers in the recirculating gas circuit of the reactor. Of the gas analyzers, the components can be fed into the accumulation gas to achieve the desired gas compositions. To ensure complete fluidization, the recirculating gas and accumulation gas are returned to the reactor base through the gas distribution plate 1, which also supports the bed of the resin when the gas flow is stopped. The gas that does not react with the bed in the reaction zone becomes the recirculated gas and passes through the rate reduction zone so that introduced particles can return to the bed. The recirculated gas is then circulated through a compressor 4 through two heat exchangers 3 and 6 in series to remove the heat of reaction absorbed from the bed before returning the gas to the bed. The compressor is located between the two heat exchangers. In addition to a polymerizable olefin, hydrogen as a component in the gas stream provides a chain transfer agent for polymerization reactions. Also, any inert gases for the catalyst and reagents in the gas stream may be present. It is well known that the temperature of the fluid bed reactor is preferably maintained below the sintering temperature of the polymer particles. For the production of ethylene polymers, an operating temperature between 30 ° C to 120 ° C must generally be maintained). The reactor pressure can be operated at pressures up to 1000 psig (70.0 bar), and preferably 150 to 400 psig for this particular mode, with operation at higher pressures at such intervals that favor heat transfer as an increase in pressure increases the heat capacity per unit volume of the gas. Under a particular group of operating circumstances, the extraction stream 8 of the polymer removes the polymer from the reactor in a proportion equal to the production of the polymer in the reactor, in such a way that the level of the bed of the fluidized bed is maintained at a constant level. Traditional Ziegler Natta catalysts typically used in the art comprise a transition metal halide, such as titanium or vanadium halide, and an organometallic compound of a Group 1, 2, or 3 metal, typically trialkylaluminum compounds (typically referred to in US Pat. present later as "alkyl"), which serve as an activator for the transition metal halide. Some Ziegler Natta catalyst systems incorporate an internal electron donor that forms a complex in the aluminum alkyl or transition metal. The transition metal halide may be supported on a magnesium halide or a complex therefor. This active Ziegler Natta catalyst can also be impregnated in an inorganic support such as silica or aluminum oxide. This active Ziegler Natta catalyst can also be prereacted to a certain degree under appropriate conditions to form a modified catalyst referred to as a prepolymer, prior to introduction into the main fluidized bed reactor. In order to stop the polymerization of a polyolefin process, it is preferred to stop the injection of the catalyst and, if it is being used, the injection of the cocatalyst (for example, trialkylaluminum) into the reactor (as used hereinafter, the term "catalyst" is understood to include cocatalyst, when present). Stopping these feeds to the reaction process will not stop the polymerization immediately if all other process parameters such as temperature, pressure, gaseous composition of the reactor, gas velocity of the reactor, etc. they remain constant, since the active catalyst, which is still present in the reactor, continues to react with the available monomer. This deactivation stage can last for a considerable amount of time. Therefore, to effectively reduce the polymerization in a short period of time while maintaining all other process parameters, a catalyst stop agent is injected into the gas of the reaction process. Without joining any particular theory for the function and efficacy of the invention, in the present invention it is believed that there are two general types of deactivating agents that deactivate the activity of the catalyst. The first type is referred to as an irreversible arrest or deactivation agent. The irreversible arresting agent irreversibly removes the ability of the catalyst to react with olefins. The polymerization process will not proceed without the addition of the fresh catalyst. Water and oxygen are typical arrest agents of the irreversible form. The second type, which is preferred for this invention as a stopping agent, is referred to as a reversible stopping or deactivating agent. Carbon monoxide and carbon dioxide are typical arrest agents of the reversible form. These arresting agents usually inhibit the active catalyst sites which prevents polymerization for a limited time under normal reaction conditions. Although the addition of the fresh catalyst is preferred to restore operating conditions, some product may be produced as soon as the reversible arresting agents leave the active catalyst sites. In the process according to the present invention, once the catalyst feed (and alkyl feed if present) has stopped, a predetermined amount of a specific stopping agent is injected into the process, preferably in the upstream of the fluidized bed gas circuit which prevents the active catalyst sites from reacting further with the olefin, in turn, limits the polymerization to the desired ratio. Again, the amount of the stop agent required by the ordinary technician can be determined without prolonged experimentation, since the amount of the catalyst is known, for example, from knowledge of the amount of the catalyst in the product together with the bed volume. . In this way, the amount of the detention agent to be added is "predetermined". Additionally, if the addition of alkyl is present prior to injection of the stopping agent, a certain amount of the stopping agent will react with the alkyl. Therefore, a greater amount of the stop agent must be added to compensate for the debugging effect of the alkyl if the desired amount of active catalyst sites is deactivated. In contrast to the technologies that use an agent to completely kill the reaction to prevent sintering of the reactor bed in case of or failure of the recirculating gas compressor or technologies that use an agent to transition from one catalyst to another, this process in the present invention allows the reaction process to be temporarily stopped and restored at any desired time of production of products with the desired properties. Since the invention works by reducing reaction rates, the invention is particularly applicable to all types of polyolefin fluidized bed reactors, although one skilled in the art will recognize that the invention is more broadly applicable to any polymerization reaction using a system of catalyst that can be deactivated, such as a polyester reaction, reactions in solution, etc. The level of successful arrest of the reactor obtained will depend on the type of catalyst system in use, including any inorganic support structure such as MgCl2 or silica, but the general utility of the invention results from the interaction of the catalyst with the arresting agent. In a preferred embodiment, the present invention is applicable to polyethylene fluidized bed reactors, and even more preferably applicable to polyethylene fluidized bed reactors using a Ziegler Natta catalyst with a MgCl2 support. In the most preferred embodiment, it is still more preferable that the stop agent be added to the reactor gas circuit. The stopping agent used in the process according to the present invention can be any catalyst deactivating agent with the catalyst system in use, but in the most preferred mode of polyethylene fluidized bed rectors using a Ziegler Natta catalyst with a MgCl2 support, it is preferred that carbon monoxide, carbon dioxide, or a mixture thereof be used as the arresting agent. The degree of reaction suppression of different detention agents in the different catalyst systems must be determined for each particular case. For a polyethylene fluidized bed reactor with Ziegler Natta supported catalyst system, titanium halide, MgCl 2, the preferred proportion of the carbon monoxide stopping agent, the titanium in the catalyst providing adequate reaction suppression is in the range from 0.00366 to 0.0684 mol / mol of Ti, preferably 0.02 to 0.045 mol / mol of Ti, more preferably approximately 0.038 mol / mol of Ti. Thus, it can be seen that for a typical fluidized bed process using a transition metal catalyst, the amount of the stop agent needed will be less than 1 percent, on a mol / mol basis, of the amount of the catalyst in the system. According to the preferred embodiment of the present invention, the arresting agent can be injected anywhere along the gas circuit recirculation line. More preferably, a faster response results when the injection is located after the heat exchange 6 of secondary gas recirculation and is more preferred directly below the distribution plate. As used in this, the term ethylene polymers, copolymers of ethylene, or polyethylene also includes copolymers composed of ethylene and one or more olefins (comonomer). These other olefins are preferably alpha olefins. Also included in this definition of polymers are terpolymers of ethylene and two or more comonomers. Examples of suitable alpha olefins include, but are not limited to, propylene, good-1, penten-1, hexen-1, 4-methylpenten-1, and buten-1 which is more preferred. Key elements are illustrated in the reactor circuit for a preferred embodiment of the reactor in Figure 1 and include reactor vessel 9, heat exchangers 3 and 6, compressor 4, and gas distributor plate 1. The following examples are proposed to illustrate the present invention. Numerous modifications and variations will be suggested by those skilled in the art, and it is understood that the invention may be practiced otherwise than as specifically described herein. Example 1 A conventional gas phase fluidized bed polyethylene reaction process is used as described in U.S. Patent No. 5,332,706 (incorporated herein by reference) and which is modified as shown in the Figure 1. A conduit is opened to introduce 100% carbon monoxide gas at a pressure of approximately 900 psig (63.1 bar) from a cylinder in the recirculation duct at a distance of 10 feet (3.05 m) from the reentry into the lower part of the reactor. Above, the distribution plate in the reactor contains a fluidized bed consisting of linear low density polyethylene powder. The reaction gas mixture, 67% by volume of nitrogen, 25% of ethylene, 4% of hydrogen, and 4% of 1-hexene, flows through the fluidized bed at a pressure of 300 psig (27.7 bar), to 183 ° F (84 ° C) and with an upward fluidization velocity of 1.7 ft / s (0.518 m / s). In an incident where the temperature in part of the bed reaches approximately 212 ° F (100 ° C), the stopping operation begins immediately by stopping injections of the catalyst into the reactor. Simultaneously, the measured quantity of the carbon monoxide gas contained in the duct in the reactor is introduced in less than 30 seconds, at a capacity of 0.038 mol per mol of titanium, decreasing the pressure in the duct of 900 psig (63.1 bar) at 300 psig (21.7 bar). It is found that the reaction is stopped within 15 minutes with a reactor bed temperature differential, approximately 3.6 ° F (2 ° C), and without any harmful effect, ie large agglomerates. The reactor pressure is maintained at 300 psig (21.7 bar) and the gaseous compositions are also maintained under pre-injection conditions. Under these conditions, the polymerization reaction is restarted after the introduction of fresh catalyst, without the addition of a catalyst activator and / or poison scavenger, without the bed having to be drained and even without having to purge the gas mixture of reaction of the reactor. Example 2 The operation of the reactor is carried out under conditions that are identical with those given in Example 1. A different incident occurs where the dust extraction system undergoes blockages that prevent the removal of the polymer powder from the reactor. The stopping operation is performed in the same manner as in Example 1 to prevent the fluidized bed from reaching the high levels where the bed starts to be transferred to the gas recirculation stream. The reaction is stopped within 15 minutes with a reactor bed temperature differential, approximately 3.6 ° F (2 ° C) and without any harmful effect, ie producing large agglomerates. The reactor pressure and gaseous compositions are maintained under pre-injection conditions and the level of the fluidized bed remains constant. The reaction is restarted in the same manner as in Example 1. The above examples clearly illustrate that a stopping agent can be added to deactivate a catalyst involved in a polymerization process in a predetermined amount such that the polymerization process can be be restarted immediately simply by the introduction of fresh catalyst. The invention has been described above in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications different from those specifically described herein may be made within the spirit and scope of the appended claims. On the other hand, all patents and references of literature or other publications indicated hereinabove for reference for any description pertinent to the practice of the invention.

Claims (27)

1. CLAIMS 1. In a polymerization process that includes a catalyst, a process to reduce the reaction rate of the polymerization process by adding a catalyst deactivator, the improvement characterized in that it comprises adding a deactivating agent in an amount less than the amount stoichiometric necessary to deactivate the catalyst, in such a way that the polymerization process can be restored simply by adding fresh catalyst.
2. 2. The process according to claim 1, characterized in that the polymerization process occurs in a fluidized gas phase reactor.
3. 3. The process according to claim 2, characterized in that the polymerization process occurs in a low pressure gas phase fluidized bed reactor.
4. 4. The process in accordance with the claim 1, characterized in that the polymerization process includes the polymerization of olefins.
5. 5. The process in accordance with the claim 2, characterized in that the polymerization process includes the polymerization of olefins.
6. 6. The process according to claim 1, characterized in that the catalyst includes titanium.
7. 7. The process according to claim 2, characterized in that the catalyst includes titanium.
8. 8. The process according to claim 1, characterized in that the reaction is reduced from 85% to 99% of the production before the addition of the deactivating agent.
9. 9. The process in accordance with the claim 5, characterized in that the catalyst includes titanium.
10. 10. The process according to claim 1, characterized in that the deactivating agent is a Lewis base.
11. 11. The process in accordance with the claim 1, characterized in that the deactivating agent is selected from the group consisting of carbon monoxide, carbon dioxide, water, oxygen and mixtures thereof.
12. The process according to claim 1, characterized in that the deactivating agent is selected from the group consisting of carbon monoxide, carbon dioxide, and mixtures thereof.
13. The process according to claim 5, characterized in that the deactivating agent is selected from the group consisting of carbon monoxide, carbon dioxide, and mixtures thereof.
14. The process according to claim 13, characterized in that the catalyst is titanium and the deactivating agent is present in the amount of 0.00366 to Q.0684 moles per mole of titanium.
15. 15. The process according to claim 1, the polymerization process characterized in that it comprises the production of polyolefins and includes the continuous addition of fresh catalyst, wherein the process to reduce the ratio consists essentially of stopping the fresh catalyst feed and adding the deactivating stopping agent, without any change in reactor temperature or pressure, and which further includes an additional step to reestablish the production of polyolefins, the additional step essentially consisting of adding fresh catalyst.
16. 16. A process for stopping a reactor process, wherein the reactor process includes a catalyst, characterized in that it comprises adding a stopping agent to the reactor in an amount just enough to stop the reaction process, so that the reactor process it can be restored simply by adding fresh catalyst
17. 17. The process according to claim 16, characterized in that the aggregate moles of the stopping agent are less than the moles of the active catalyst present.
18. 18. The process according to claim 16, characterized in that the arresting agent is a Lewis base.
19. The process according to claim 16, characterized in that it comprises the polymerization of olefins in a gas-phase fluidized-bed reactor at low pressure, wherein the catalyst includes a transition metal catalyst selected from titanium and vanadium.
20. 20. The process according to claim 19, characterized in that the arresting agent is selected from the group consisting of carbon dioxide, carbon monoxide, water, oxygen and mixtures thereof.
21. The process according to claim 1, characterized in that the arresting agent is selected from the group consisting of carbon monoxide, carbon dioxide, and mixtures thereof.
22. 22. The process according to claim 21, characterized in that the transition metal is titanium and the arresting agent is present in the amount of 0.00366 to 0.0684 moles per mole of titanium.
23. 23. The process according to claim 16, characterized in that the reaction is stopped 85% to 99% of the production before the addition of the stopping agent.
24. 24. The process according to claim 16, characterized in that it further comprises the step of restoring the reaction by a step that includes the addition of fresh catalyst.
25. 25. The process according to claim 21, characterized in that it further comprises the step of restoring the reaction by a step that includes the addition of fresh catalyst.
26. 26. The process according to claim 16, characterized in that it further comprises the step of restoring the reaction by a step consisting essentially of adding fresh catalyst.
27. 27. The process according to claim 21, characterized in that it further comprises the step of restoring the reaction by a step consisting essentially of adding fresh catalyst.