JP6068437B2 - FCC method to maximize diesel using two separate converters - Google Patents

Description

  The present invention relates to the field of fluid catalytic cracking (FCC) and relates to maximizing middle distillate. More specifically, the present invention represents an FCC process that uses heavy hydrocarbons or mixtures of hydrocarbons as feedstock, where one converter is dedicated to producing the highest quality LCO (light cycle oil) Use two different converters operating in harmony, dedicated to “re-cracking” the undesired (decanted oil) or non-standardized (naphtha) stream produced by the first converter Propose that. Furthermore, the present invention represents the benefit of using short contact times as a way to reduce the severity of the reaction in the converter to produce high quality LCO. The method maximizes LCO production and improves its quality while producing the required quality of gasoline and reducing the production of fuel oil, thereby addressing the typical problem of maximum LCO operation. The purpose is to remove.

  Combined with increased consumption of gasoline competitors such as alcohol and natural gas, diesel engines are becoming more efficient compared to gasoline engines, resulting in higher global demand for diesel than gasoline demand Has increased. As a result, refineries around the world are interested in maximizing their diesel production units.

  One of the streams produced by the FCC unit is LCO (light cycle oil) having a boiling range similar to diesel. Adding it to a diesel pool is inherently limited by its aromaticity and density. This improvement in flow quality generally allows the refinery to produce more diesel because it can increase its proportion in the diesel pool.

  Maximizing the production of middle distillate by FCC is not new per se. The most commonly employed approach to maximize LCO production involves minimizing the severity of the reaction. The most common approach relates to converter operation at low reaction temperatures (TRX) of about 450 ° C. to 500 ° C. with the use of low activity catalysts. Under these conditions, LCO production increases and quality improves. The problem is that undesirable factors such as increased production of decanted oil (DO) and degraded naphtha quality accompany this benefit and prevent its introduction into the gasoline pool. Performing FCC operation at a very low reaction temperature also adversely affects the thermal balance of the converter and also reduces the operational reliability of the unit.

  The presented invention relates to a fluid catalytic cracking (FCC) process involving two converters operating in a coordinated manner. Throughout this section and throughout the document, the converter shall provide a reaction zone and regeneration zone for a raw material cracking reaction, including the use of a particulate catalyst to effect the catalytic reaction mechanism, regeneration of the spent catalyst, and flow catalyst with powder flow characteristics. Refers to a collection of devices that allow transport between In addition, the converter itself contains a single catalyst formulation in its item.

  The presented method produces gasoline of the required quality and, in addition to reducing fuel oil production, maximizes LCO production and improves its quality, typical of maximum LCO operation. The purpose is to remove the problem.

  Catalytic cracking in a fluidized bed plays an important role in essential oils, especially when heavy hydrocarbons that are difficult to distill must be processed. The main features of this method are that it is possible to tailor the production according to actual market needs and to recycle fractions of low commercial value derived from other purification methods.

  The FCC unit has an intermediate heavy oil fraction that produces lighter products (more traumatic gasoline and intermediates) with higher added value through chemical reactions that break down the molecules with zeolite catalysts. This type of decomposition occurs at lower control temperatures than thermal decomposition.

  Since the FCC method has been used industrially since the 1940s, it is a technique of a method that has been extensively described in the literature. An introductory reference to the FCC process is “Fluid Catalytic Cracking Technology and Operation”; Wilson, J. et al. W; Pennwell Books edited by 1997;

  An overview of the basic aspects of FCC technology can be found in patent application PI 0504321-2, which is used as a reference for the following description.

  The cracking reaction occurs by contacting hydrocarbons in a tubular or riser reaction zone with a catalyst containing particulate material. The feedstock that is most often subjected to the FCC process is generally the refinery stream coming from the side-cuts of the vacuum tower, known as heavy vacuum gas oil (HVGO), or atmospheric residue (AR) Heavier distillates such as those coming from the bottom of the atmospheric tower, or a mixture of these streams.

  These streams, with densities typically ranging from 8 ° to 28 ° API, are substantially modified in their composition to convert them to lighter hydrocarbon streams of higher economic value. Chemical methods such as catalytic cracking must be applied.

  During the cracking reaction, a substantial proportion of coke, i.e. by-products of the reaction, is deposited on the catalyst. Coke is a high molecular weight material consisting of hydrocarbons that typically contain 4 to 9 weight percent hydrogen in their composition.

  At the end of the reaction in the riser, the recovered coke catalyst, commonly known as “spent catalyst”, must be separated from the cracked product. This separation process is typically performed in a cyclone contained in a container known as a “separator vessel”.

  Patent documents PI 9307773-2 (including a high speed separation system at the end of the riser), PI 0204737-3 (improvement by introducing a hydrocarbon vapor recovery pipe into the system, which is incorporated herein in its entirety by reference. Applicant's separation techniques described in PI 0704443-7 (including application of a high speed separation system to a converter having two or more risers) are used in this method. This is a preferred technique.

  The separated spent catalyst is rectified to recover this residual hydrocarbon because it still contains some amount of valuable cracking products that are either trapped between the catalyst particles or absorbed on its surface. There must be. This treatment is generally performed in a rectification column, which is an apparatus connected to a separator vessel. The rectification fluid is generally a flow that flows opposite the spent catalyst flow. The internal structure of the rectification column allows closer contact between the catalyst particles and the rectification stream.

The extracted hydrocarbon and rectification stream joins the cracked product stream already separated in the cyclone, and the separator vessel passes through the transport line to collect the characteristic FCC stream. Makes it possible to move up to.
FG: fuel gas—inert gas of this process, H ₂ S, H ₂ , and C1 and C2 hydrocarbons;
LPG: liquefied petroleum gas C3 and C4;
Acidic water: the sum of all vapor streams injected into the top system of the reaction zone and fractionation, including high levels of contaminants such as H ₂ S;
GLN: cracked naphtha specified as gasoline-typically a C5 + hydrocarbon with a final boiling point (FBP) of 220 ° C;
LCO: Light cycle oil-a hydrocarbon typically having an IBP of 220 ° C and an FBP of up to 340 ° C;
DO: Decanted oil—a hydrocarbon (residual product) typically having an IBP of 340 ° C. +.

  The cracked naphtha stream can be fractionated into light naphtha (LN) and heavy naphtha (HN) at the fractionation temperature most suitable for the refinery. In addition, in some configurations, the circulating reflux stream is removed from the column as an intermediate product of LCO and DO, a heavy cycle oil (HCO) stream.

  Subsequently, the spent catalyst at the outlet of the rectification column containing carbonaceous material that cannot be rectified is sent to the regenerator vessel. The coke deposited on the catalyst surface and pores is then burned in this vessel operating at high temperatures. The removal of coke by combustion allows the recovery of catalyst activity and releases a sufficient amount of heat to meet the thermal requirements of the catalytic cracking reaction.

  The fluidization of the catalyst particles by the gas flow allows transport of the catalyst from the reaction zone to the regeneration zone and vice versa. Besides fulfilling the basic function of promoting the catalysis of chemical reactions, it also acts as a means of transporting heat from the regenerator to the reaction zone.

  There are many descriptions of this technology, including hydrocarbon catalytic cracking in a fluidized catalyst stream, transporting the catalyst between the reaction zone and the regeneration zone and burning the coke in the regenerator.

  From the beginning, fluid catalytic cracking (FCC) has been basically adapted to produce high-octane gasoline and is also responsible for producing LPG. Middle distillate (LCO) produced by this conventional method accounts for 15% to 25% by weight of the total yield. LCO typically has a high concentration of aromatic components, reaching over 80% of the total composition, making it difficult to formulate it into a diesel oil pool.

Aromatic components in the LCO range degrade quality and reduce cetane number (an index based on linear paraffin hydrocarbons with the chemical formula C ₁₆ H ₃₄ used as a basis for evaluating diesel ignition properties). Increases the characteristic density that cannot be completely reversed by hydrogen treatment. Therefore, minimizing the formation of aromatic components in the FCC is an important strategy for maximizing middle distillate. The aromatic component in the FCC product can be generated directly from the feed through a dealkylation reaction of larger aromatic molecules, or it can be formed from olefins that circulate and then undergo a hydrogen transfer reaction. The formation of aromatic components from olefins occurs in secondary reactions, and the low reactivity of aromatic components increases the concentration in the product of these molecules as the conversion proceeds, and other species that are more reactive. From the reaction medium. Secondary aromatic formation reactions that are undesirable to obtain a better middle distillate are facilitated by highly harsh conditions, including high reaction temperatures and high contact temperatures between the batch and catalyst in the riser.

  Although the FCC process was originally developed for the production of high octane gasoline, the inherent flexibility of this process allows for example the middle distillate of diesel oil, or even the petrochemical industry (FG and It is possible to adapt to different production purposes, such as maximizing light olefins (present in LPG). Maximizing the middle distillate and maximizing light olefins are the exact opposite kind of operation. Operation for middle distillates is usually low conversion to maintain LCO yield (boiling point in the range of 220 ° C to 340 ° C) that is greater at conversion levels lower than those used in typical FCC operation. Need. On the other hand, operations to maximize light olefins require very high conversion rates that go into the area of gasoline overcracking. For this reason, it is difficult to simultaneously obtain a high olefin yield and a high yield of better quality LCO in a single reaction zone.

In view of the growing demand for high quality middle distillates that would be detrimental to the gasoline market, changes were made to the way the FCC unit was operated to increase the production of LCO in this process. Some documents in the patent literature include catalyst systems and process variables to achieve reduced process severity so as to increase the middle distillate yield and reduce the aromatic content in this fraction. It is described to change. These changes include the following:
-Reduction of reaction temperature (TRX);
-Reduction of contact time;
-Reduction of the catalyst / oil (C / O) ratio; and-reduction of the catalyst activity.

  Any modification of these operating variables results in a reduced conversion rate, resulting in increased production of DO and degraded naphtha quality.

  The most commonly used approach to maximize LCO production is to minimize the severity of the reaction by operating the converter at a low reaction temperature of 450 ° C. to 500 ° C. in conjunction with the use of a low activity catalyst. Including restraining. Under these conditions, LCO production increases and quality improves. The problem is that when this approach is applied, some undesirable side effects such as increased production of DO and reduced naphtha quality prevent naphtha from being added to the gasoline pool. Will occur. In general, another attendant undesired factor caused by the reduced severity of the reaction is a reduction in LPG production, resulting in a reduction in light olefin production in LPG.

  A detrimental result due to FCC operation to maximize middle distillate by reducing reaction temperature is the excessive deposition of coke observed in the reaction zone and rectification zone. Coke deposition at the riser, separator vessel cyclone, transport line, and bottom of the rectification column is common in low temperature reaction conditions. This problem reduces the operational reliability of the unit and often requires its complete shutdown for coke removal and cleaning.

  The main cause of coke over-deposition is that the vaporization of the feed is due to the lower production temperature in the feed-catalyst mixing zone as a result of the lower reaction temperature used to maximize the middle distillate. It will be insufficient.

  Another disadvantageous result of FCC operation to maximize middle distillate by reducing reaction temperature is that the operating range is 670 ° C. to 730 ° C. (regenerator high density phase temperature) in a high density catalyst bed. There must be a fast rise in regenerator temperature. Excessive temperature rise in the regenerator is disadvantageous because it increases the deactivation rate of the unit catalyst varieties in addition to bringing the regenerator vessel closer to its metallurgical design limit. It also significantly enhances the potential rubbery quality of cracked naphtha, and the greater heat received by mixing the raw material with a higher temperature catalyst resulting from a higher temperature regeneration zone, even at a lower TRX. Has the undesirable effect of causing degradation.

  The rapid increase in regenerator temperature during operation at low reaction temperatures is mainly due to increased hydrocarbon contamination in the regenerator. This additional contribution of fuel combusted in the regenerator, accompanied by a reduction in the circulation of the catalyst in the unit (due to a decrease in the reaction temperature in the riser), causes a fast increase in the regenerator temperature. Secondly, due to the lowering of rectification efficiency, the lower raw material conversion rate as a result of the lower temperature in the rectifying column with the reaction temperature and the lowering of the temperature of the mixture at the base of the riser with the reaction temperature The increase in the non-vaporized portion increases the concentration of higher molecular weight components in the gas flowing into the rectification column, thereby increasing hydrocarbon contamination.

  The adverse effects on FCC-operated regenerators with reduced reaction temperatures are exacerbated when processing heavy residual feedstocks that tend to be more difficult to vaporize and convert.

  The temperature of the regenerator can be corrected by a catalyst cooling unit (catalyst cooler or catalyst cooler) in the regenerator vessel. The catalyst cooler was cooled while receiving a flow of hot catalyst from the vessel, exchanging heat with the tube bundle where water flows and saturated steam is generated, and maintaining the regenerator's dense phase temperature within the proper operating range. Return the catalyst flow to the regenerator. Its use has the disadvantage of increasing the air demand for the regeneration zone by increasing the overall coke yield due to its effect on the overall energy balance of the converter, in addition to increasing the complexity of the device.

  Another method for correcting the temperature of the regenerator is to provide a cooling “quenching” fluid flow to the riser, preferably above the main feed injection point, as described in patent application PI 0504854-0. Consists of injecting into a point.

  “Quench” injection results in an increase in energy demand for the riser and an increase in catalyst circulation from the regenerator to the riser. This additional removal of the hot catalyst from the regenerator indirectly contributes to reducing the temperature of the dense catalyst bed of the regenerator. Another advantage of “quenching” is that it contributes to better vaporization of the feedstock (especially important for heavy feedstocks) and its bottom decomposition, reducing the production of DO and converters due to the presence of unvaporized feedstock The increase in the temperature at the base of the riser (for the same final reaction temperature) that reduces the coke deposits on. Like the catalyst cooler, this alternative has the disadvantage that it requires the use of a larger combustion air flow as a result of increasing the overall coke yield of the unit.

  The above technique does not solve the problem of mixing hydrocarbons into the regenerator. In this aspect of reducing the reaction temperature, Applicants' high speed separation technology, which is the object of patent PI 930377-2, and the aforementioned patent applications PI 02074737-3 and PI 0704443-7, which is incorporated by reference in its entirety, is Since it plays an important role in reducing hydrocarbon batches to the distillation column, it contributes to the reduction of contamination in the regenerator.

  In addition to reducing the reaction temperature, another way to reduce the severity of the reaction to operation to maximize middle distillate is to reduce the contact time between the feed and catalyst in the riser. . When the contact time is shortened, there is no secondary reaction forming an aromatic component, and a better quality LCO is produced. At the same time, however, the bottom cracking reaction is expanded, leading to an increase in undesirable DO production similar to that produced when the reaction temperature is reduced.

  However, in operations directed toward middle distillates, the reduction in reaction severity due to short contact times provides advantages compared to that due to reduction in reaction temperature. This achieves the same goal of maximizing the middle distillate by choosing to use a short contact time, by operating at a higher reaction temperature than the reduction in severity is solely due to the reaction temperature. This is because it becomes possible. Throughout the course of the invention, the inventor has shown that using short contact time temperatures associated with higher temperature operation maintains the LCO production and quality improvement and eliminates the problem of reduced efficiency in the rectification column. Have learned. In addition, the highest temperature at the base of the riser (determined by the highest TRX) allows for better vaporization of the feed, eliminating the disadvantages of reaction and coke deposition on the rectification unit. Similar to the use of “quenching”, better vaporization of the batch, and the highest temperature throughout the riser with short contact times, allows this means to be used for decomposition of the residual batch. The resulting high concentration phase temperature, as already mentioned, increases the efficiency of the rectification column and reduces the delta-coke by reducing the contact time in the reaction zone, as well as the heavy distillation to the catalyst. This is reduced by reducing the deposition of minutes resulting in better vaporization of the feedstock.

  For those familiar with FCC technology, delta-coke is the ratio of yield by weight of feed coke to mass ratio of catalyst circulation / feed flow (catalyst / oil or C / O ratio). C / O translates to units of catalyst mass per unit of batch mass. Thus, delta-coke indicates the amount of catalyst required to produce a specific amount of coke as defined by the converter heat demand. The smaller the delta-coke value, the greater the catalyst circulation required to produce a given coke yield in the unit (higher C / O). This ultimately promotes increased catalyst circulation and removes heat from the regenerator to the riser, thus cooling the regenerator with smaller delta coke (lowering the dense phase temperature). Means that. Shortening the contact time, under these conditions, only the larger catalyst circulation (higher C / O) that compensates for the shorter reaction time available in the riser requires the coke yield required to meet the converter thermal balance. Is achieved, delta-coke is reduced.

  Applicant's patent application PI 0504321-2 shows a method aimed at eliminating the disadvantages of increased production of DO and reduced gasoline specification due to reduced severity operation. The method is characterized by using a single converter with two separate reaction sections with two separate fractions. The feed (stream 10) is introduced into the less severe reaction section of the converter in the riser at a temperature of 460 ° C. to 520 ° C. (maximum LCO mode). The reaction products are removed from the "LCO for Diesel" stream (stream 66) and the non-specificated cracked naphtha stream (stream 64) and DO (high yield stream 68 with low severity). Is separated by a fractionation tower. These latter two undesired streams are recycled again to the converter, the other reaction section, and more severely decomposed in the riser at a temperature of 550 ° C to 620 ° C. The separator vessel receiving the product from this riser is independent of the previous one, and this latter product is separated from the specified cracked naphtha stream (stream 74), lower yield. The DO stream (stream 76) and low aromatic LCO with high aromatic content (stream 75) can be sequestered in a separate fractionation column. This design makes it possible to isolate better quality LCOs from lower quality LCOs to avoid “contamination” of these streams having the same boiling range. Furthermore, it is possible to generate naphtha standardized in the gasoline pool and reduce the generation of DO. The rise in regenerator temperature is prevented by a “quenching” function in which naphtha re-disassembly in the second riser is performed on the entire converter.

  This invention, which considers a single converter, has the disadvantage of using a single catalyst system in an unconventional manner. For batch risers, it is desirable to use a less active catalyst system to maximize LCO, and for naphtha / DO risers, maximize the degradation of non-standardized naphtha to obtain the required quality. And using a higher activity catalyst suitable for cracking the recycled DO of the first fractionator that compensates for LPG production and is sufficiently resistant to cracking. desirable. A differentiated catalyst system is also necessary to allow naphtha to be broken down into high-value light olefins that are used as feedstock for the petrochemical industry. This fact, ie the presence of a single converter, prevents ideal optimization of the catalyst system which limits the results that can be achieved through the configuration proposed in patent application PI 0504321-2.

  Another point is that naphtha and DO re-decomposition occurs in a single riser. Since these streams have different properties, the ideal conditions for decomposing them are also different. Having a single riser prevents the ideal catalytic cracking conditions of these streams from being optimized and limits the results that can be achieved.

  In addition, the operational reliability of the converter is reduced due to problems associated with coke deposition on the equipment in the reaction and rectification sections associated with lower riser temperatures. In practice, the application of this method can be limited to the processing of lighter raw materials.

  Production of diesel and LPG in a single converter with two risers, one of which is a low severity riser to maximize LCO and a high severity riser to re-disassemble naphtha US Pat. No. 7,632,977, which is intended to increase simultaneously, has the same disadvantage of using a single catalyst system for the feed and naphtha cracking. Also, higher severity is required for the converter because DO recycling is sent to a point above the low severity riser feed and complicates the decomposition of this stream. Thus, a significant reduction in DO production is not expected and continues to be a problem for refineries wishing to increase LCO diesel production without offsetting the increase in DO production. In addition, the problem of coke deposition in low severity reactors is doubled by the recycling of decanted oil whose vaporization is hindered by the selected injection point.

  Patent application PI 060509-3 discloses a converter with a double riser with the difference that no stream is recycled. Because the riser operates at different severity, the product production profile and quality are different between the two risers. An advantage of this design is the increased raw material throughput of the unit, which means an increased conversion feed to the refinery because the second riser is not tied to the first riser reprocessing stream. However, the disadvantage is due to the larger amount of non-standardized naphtha and DO being produced in the first riser.

  U.S. Patent Application No. 2006/0231458 discloses an FCC process that claims the use of short contact times in the riser focused on increasing gasoline and middle distillate production. This method uses a single riser and the contact time is 1 to 5 seconds (but generally a short contact time is characterized by a time of less than 2 seconds). This document lists some of the advantages of short contact times, such as reducing non-selective reactions and reducing undesirable hydrogen transfer reactions that lead to the formation of aromatic components in the degradation products. Reduction of fuel oil production is achieved by selective DO recycling, ie, a stream of DO from which triaromatic compounds (hydrocarbons having more than three aromatic rings) have already been removed. This less aromatic DO stream is most reliably decomposable and has a higher conversion than raw DO from fractionation towers even with low severity risers. However, this method requires a separation step to separate “degradable” DO (saturates and one / two aromatic components) and aromatic residues (triaromatic components) (in that patent application) Possible separation methods include solvent extraction, chromatography and membrane separation). Furthermore, it is extremely difficult to obtain high quality LCO and naphtha that are specified as gasoline by cracking the feed in a single riser.

In WO 01/60951, the second riser has two risers that are directed exclusively to reprocessing DO derived from both the first riser and the second riser itself. An FCC method using is disclosed. As described in patent application PI 0504321-2, the FCC method of WO 01/60951 exhibits several drawbacks as follows.
-A single recycle stream from the first riser operating at lower severity is DO. As a result, the quality of the naphtha coming from this riser is not good.
-The naphtha and LCO streams in the first riser are not separated in the fractionator attached to this riser, but instead are mixed with the same fraction obtained in the second DO riser . As a result, the LCO and naphtha obtained in the first riser are mixed with those obtained in the fractionator of the second riser. If the severity of both risers is low, the resulting LCO is good quality, but the DO reprocessing loses its effectiveness, and this method usually produces a large amount of DO (and low naphtha quality). ). On the other hand, if the second riser is more severe, the DO conversion rate will increase, but the quality of the LCO in the second riser will decrease, and this flow will mix with the LCO obtained in the first riser And the overall result is that the improvement in LCO quality is significantly reduced.
-In the design shown in that patent, the catalyst systems of the two risers are identical.
-The problem of coke deposition with the first riser can limit the reduction of the reaction temperature inside it and limit the quality of the raw material being processed.

US Pat. No. 6,416,656 describes a method for increasing the overall yield of diesel and LPG using risers. In this method, gasoline is re-decomposed to increase the LPG yield, and at the point where the severity of the riser is higher in both the reaction temperature and the ratio of the catalyst mass unit to the feed mass unit (C / O ratio). Inject at a point below a filling nozzle. Process feed is injected at multiple points along the riser to reduce contact time and further increase the yield of LCO; in addition, at the top of the riser (by injecting additional feed into the riser) As with the C / O ratio, the temperature has already dropped, which is also advantageous for LCO yield and quality. In addition, a “quench” is injected at the top of the riser to stop the secondary reaction. Reducing the severity of the portion for cracking the raw material can lead to an undesirable increase in DO production. However, the patent shows that DO can be recycled along with the raw materials. The disadvantages of this technique are as follows.
-The refinery's flexibility decreases as the unit's operating window becomes narrower because a single riser is used for raw material decomposition and naphtha and DO recycling.
-Most of the installed risers are used for reprocessing, reducing the space in the refinery to convert the residue.
-Since one riser is used, the injection is performed in terms of optimized temperature and C / O ratio for each flow, but the process meets its various objectives (maximizing diesel and LPG). Limited to a single catalyst system.

US Pat. No. 7,316,773 is important for the purpose of maximizing middle distillate through the development of its FCC technology for middle distillate without offsetting the increase in DO and lower gasoline quality. An FCC method is described that aims at some of the following features that the applicant considered to be:
-Use separate risers to re-crack cracked naphtha and DO to optimize reaction conditions for cracking streams with characteristic chemistry etc.
-A catalyst system specific for each purpose, ie a catalyst system for cracking the raw material at low severity (to maximize high quality LCO) and cracking naphtha under certain conditions (middle distillate) It is possible to use another catalyst system for the purpose of correcting the quality of gasoline in the FCC process towards

  However, US Pat. No. 7,316,773 does not include the possibility of an important feature to maximize the allocation of LCO obtained in FCC to refinery diesel pools. Not even. That is, one of Applicants' objectives is to produce a better quality LCO (derived from a reaction by decomposition of a less severe raw material) and a lower quality (derived from a reaction by decomposition of a higher severity DO). To separate from the LCO.

  Failure to meet this requirement significantly diminishes the possibility of improving the LCO quality of the method. This occurs, unlike the applicant's development that led to the technology of the present application, in which US Pat. No. 7,316,773 is identical in any of its concepts (FIGS. 1, 2 and 3 or combinations thereof). This is because DO re-decomposition is carried out in the same converter that decomposes the raw material using the separator vessel, the same fractionator, and, as a result, the same fractionator. This leads to the following two drawbacks.

First disadvantage: LCO in which both raw materials are mixed is obtained by mixing the reaction product of the raw material and the reaction product of DO. This leads to the following possibilities:
(A) DO is decomposed at high severity, in which case the yield of DO is lower (advantageous effect), while the quality of the LCO produced is the lowest and produced in the raw material riser Since it is mixed with LCO, the quality of this LCO is reduced (adverse effect).
(B) Or, DO is decomposed at low severity, and in this case, the quality of the mixed LCO of the two raw materials is not adversely affected. However, the overall DO yield by the unit remains high, which is undesirable.

  Decomposition in the DO riser is done at a low severity, but since DO has a greater proportion of aromatic components due to its composition, the LCO obtained from this stream is generally of a higher quality than that obtained by decomposition of the feedstock. Inferior. Typically, the only possible assignment for the LCO thus obtained is a fuel oil pool as diluent. This is because mixing the LCO obtained in the DO riser and the LCO obtained in the feed riser, regardless of the reaction conditions in the DO riser, is a preferred technique for the purpose of maximizing LCO quality. Absent.

  Second disadvantage: US Pat. No. 7,316,773 shows the possibility of using different catalyst systems for the feed and DO, but this feature is Without any contamination due to mixing, as described in U.S. Pat. No. 7,316,773, both two risers allow two product streams from cracking to flow into a single gas-solid separation vessel. It is not possible when discharging into (separator container). This mixing occurs in the separator vessel itself, the rectification system, the regenerator and the catalyst transfer standpipe, resulting in thorough mixing of the two catalytic system items over time, but the physics separating them over the entire height. If there is no barrier on the device and the standpipe is not independent, both of these properties will be lost.

  Regarding the possibility of physical partitioning, US Pat. No. 7,316 only describes a regenerator provided to separate the catalyst system for naphtha from the catalyst system used together with DO and fresh feedstock. , 773 (Fig. 2). In practice, this partition is economically unattractive, technically difficult, and its implementation is impractical. Therefore, two converters are required as proposed by the applicant in this technology. However, according to the design of US Pat. No. 7,316,773, the transfer lines of both reaction products must be interconnected, and the first drawback already shown remains.

  The technology therefore optimizes the quality of the LCO obtained from the decomposition of the raw materials to the maximum, and because this high quality LCO stream is due to the chemical nature and they require a more stringent reaction, There is a need for a fluidized catalytic cracking process of the mixed feed intended to produce a middle distillate that is sequestered from other LCO streams resulting from reprocessing of the cracked fractions that produce lower quality LCO.

  Also, despite the description of the use of short contact times (less than 1.5 seconds) in a batch riser, US Pat. No. 7,316,773, as proposed by the applicant in the art, There is no correspondence between the use of this variable and the benefits that allow iso-conversion, which is the use of higher reaction temperatures. Without this technique, the entire reaction / rectification section for raw material decomposition and DO re-decomposition is exposed to the problems of coke deposition and reduced operational reliability, which is manifested in US Pat. No. 7,316,773. The range of possible batches that can be processed in the unit to which the technology being applied is applied can be limited.

This technology constitutes Applicant's development in relation to the prior patent application PI 0504321-2 in that it incorporates the following features.
-Using a second converter exclusively for re-decomposing naphtha and DO, using a specific high activity catalyst system for these streams and another low activity catalyst system for the new feedstock. This latter catalyst system has the primary purpose of obtaining a high quality LCO.
Use separate risers for naphtha and DO, allowing a higher degree of flexibility to adjust the optimal operating conditions for resolving each of these flows.
-Obtained by operating at higher reaction temperatures, using a short contact time between the catalyst and the feed as a way to reduce the severity of the reaction in the riser of the new feed (to produce high quality LCO) The operational reliability of the unit to minimize the risk of benefit, i.e. increased rectification column efficiency, better feed evaporation at the base of the riser, and coke deposition in the reactor / rectifier unit Ensure improvement. This combination of benefits allows even the processing of heavier ingredients.

  Thus, the present invention, in addition to facilitating the standardization of the residual fraction resulting from the high aromaticity obtained through re-cracking as an aromatic residue (RARO), the standardized gasoline Two separate operating together to maximize diesel through independent decomposition of naphtha and DO streams for production and reduction of fuel oil production by conversion to lighter products Utilizing a converter provides a method that offers greater benefits than would be obtained using only a single converter.

  With some changes to the arrangement and equipment between the units, it was only necessary to set one of the two converters to a low severity condition and the other to a high severity condition. Can be expanded to a rectification tower equipped with The catalyst system is different and specific to each purpose.

  In the first, a high quality LCO stream is generated, and in the second, the batch of units is re-decomposed in addition to the first naphtha and DO streams. Depending on the converter type, the naphtha can be re-disassembled with an independent riser. DO is mixed with the batch. Alternatively, if a second converter is provided with a single riser, it is possible to re-disassemble the naphtha in the “lift” section below the injection of the batch mixture with DO.

  Regardless of the application, the use of this technology also provides the refinery with the desired flexibility to respond to changes in local demand for derivatives. By simply raising the reaction temperature and changing the raw material injection point from the upper part of the riser to the lower part of the riser, it is possible to change the “maximum LCO mode” condition to “maximum gasoline mode” and vice versa. It is. Under these conditions, the second converter will be used to break down a portion of the first converter feed stream because the increased heat demand of the first converter limits feed processing there. Become. Using these two converters makes it possible to process the same total feed stream volume, regardless of the mode of operation selected.

  A more restrictive application relates to its use in a rectification column with only one converter, which reduces the flow of non-standardized naphtha and excess decanted oil coming from a converter operating for maximum LCO. Do not choose to install a second converter for processing. In this case, the refinery takes advantage of its benefits to reduce the severity of the reaction in the converter through limited time contact to maintain the highest TRX and to remove some of the naphtha from the riser Have the option to recycle to the base. However, it is difficult to cope with the larger production of decanted oil. Choosing to recycle part of the DO or not significantly reduce the severity of the reaction so as not to increase the yield of DO results in reduced LCO quality and maximum middle distillate The introduction of this flow into the diesel pool, which is the first purpose of the converter's operation towards, will be reduced. For refineries already utilizing the low severity of the converter by reducing TRX (and being able to balance the degraded naphtha quality and excess decanted oil in the essential oil scheme) If a means for shortening the contact time is used instead of the means, the operation reliability becomes high and the operation window of the unit becomes wide.

  The present invention relates to an FCC process that uses heavy hydrocarbons or mixed heavy hydrocarbons as feedstock, and includes two separate converters that operate in harmony. The first converter operates with a short contact time of 0.2 to 1.5 seconds (preferably 0.5 to 1.0 seconds) in the riser, and even at low severity, 510 ° C. to 560 ° C. (preferably Allows higher reaction temperatures (from 530 ° C. to 550 ° C.) and uses suitable catalysts to maximize LCO. The second converter has a highly active catalyst system suitable for naphtha and DO cracking and uses conventional contact times (greater than 1.5 seconds).

  Each reaction temperature is set according to the most recommended range for maximizing the respective cracking of the stream: 530 ° C. to 560 ° C. for the DO riser and 540 ° C. to 600 ° C. for the naphtha riser. . The method aims at maximizing both LCO production and its quality, allowing the production of gasoline of the required quality and reducing the production of fuel oil to maximize LCO. In order to eliminate the typical problems encountered by refineries that operate. In addition, using a short contact time in the first converter will yield all the benefits associated with the use of a higher TRX, since a higher quality LCO is obtained even at higher reaction temperatures. . The final result was interpreted as improved operational reliability and favorable thermal balance, opening up room for raising the raw material temperature and treating the residual raw material.

Fig. 6 schematically shows a flow chart of the proposed method in its preferred embodiment in which the second converter comprises two risers for re-disassembly regardless of naphtha and DO in each riser. FIG. 1 shows the design of a new FCC unit aimed at diesel production at a refinery, and the application of the present invention at a refinery that already has two FCC converters, one converter with two risers. Indicates. An alternative approach of the present invention for applications in refineries that already have two FCC converters that are intended when both have only one riser and do not select the second riser design for one of the converters FIG. Note that in this case, the conditions for re-decomposing naphtha and DO (in the same riser) are not optimized. However, FIG. 2 reflects the decision to reduce the investment in implementing this proposal. Fig. 2 shows a block diagram of the present invention applied to an existing FCC unit.

  The present invention relates to an FCC process for maximizing middle distillate using a mixture of hydrocarbons as feedstock, which uses two different converters operating in a coordinated manner to maximize diesel. This produces standardized gasoline while simultaneously reducing fuel oil production and gains greater benefit than would be obtained using only one converter.

  FIG. 1 shows the proposal of the present invention in its preferred embodiment.

  According to FIG. 1, the converter “A” (1) comprises a riser “I” (2), a separator vessel (3), a rectification column (4), a spent catalyst standpipe (5), A regenerator (6) and a regenerated catalyst standpipe (7). In the converter “A” (1), the raw material (50a) consisting of heavy gas oil or atmospheric residue (AR) or a mixture of these streams is filled from the upper part of the low severity riser pipe “I” (2). The raw material comes into contact with the high temperature regenerated catalyst coming from the regenerator (6) via the stand pipe (7) which is a pipeline. The regenerated catalyst is initially carried by a “lift” fluid (51), which is generally a stream that helps to raise the catalyst flow to the feedstock introduction point in riser “I” (2). The flow rate must be set to ensure a stable flow of catalyst. The cracking reaction is conducted in the riser “I” (2) at a temperature of 510 ° C. to 560 ° C. (preferably 530 ° C. to 550 ° C.) using a catalyst to maximize LCO. A short contact time between the raw material and the catalyst in the range of 2 to 1.5 seconds, preferably 0.5 to 1.0 seconds is used.

  If desired, the feed is introduced into the lower feed disperser (9) at the base of the riser “I” (2), which is contacted with the catalyst with a contact time of about 1.5 to 2.5 seconds. , May allow refineries to transition between “maximum LCO mode” and “maximum gasoline mode”.

  The reaction product (52) of converter “A” (1) is a lighter hydrocarbon than feed (50a), such as gasoline, LPG, fuel gas (FG) eLCO, and decanted oil (DO). These are sent to fractionator "A" (11) to remove LCO stream (57) having a quality suitable for incorporation into a pool of feedstock for diesel hydroprocessing. A light hydrocarbon stream exits (53) from the top of fractionator "A" (11), is condensed, and then sent to the top vessel (12). The top vessel (12) separates a fraction of non-standardized naphtha (NNE) (55) and a fraction of wet gas (54) that contains mainly components in the FG and LPG range. The NNE fraction (55) is sent to the naphtha disperser (29) at the base of the riser “II” (21) that forms part of the second converter “B” (20). Alternatively, the fraction of NNE (56) can be sent to the disperser (10) at the base of the riser "I" (2) of converter "A" (1), in which case it is (catalyzed once vaporized) As a “lift” fluid (naphtha lift) for the catalyst that requires a larger amount of lift flow (51) to reach the top of the riser without injection of feed. Function. That is, in selecting to use the naphtha lift (56), the consumption of the flow (51) for the catalyst "lift" in the riser "I" (2) is reduced and the converter "A" (1) The production of acidic water in the fractionation part is reduced. The naphtha lift (56) must be adjusted for the quality of the LCO (57) separated in fractionator "A" (11) so as not to impair its formulation into the refinery diesel pool.

  Decanted oil (DO) stream (58) exits from the bottom of fractionator "A" (11) and is located at the base disperser (30) of riser "III" (28) of converter "B" (20). ). Converter “B” (20) includes riser “II” (21), separator vessel (22), rectification column (23), spent catalyst standpipe (24), and regenerator (25). And a regeneration catalyst standpipe (26) interconnecting the regenerator (25) and the riser pipe "II" (21), and a regeneration interconnecting the regenerator (25) and the riser pipe "III" (28). It includes a catalyst standpipe (27) and a riser “III” (28).

  In the high severity riser tube “II” (21), the NNE (55) contacts the hot regenerated catalyst coming from the regenerator (25) via the tube, ie the stand pipe (26). The regenerated catalyst is initially carried by a “lift” fluid (59), which is generally a stream that helps raise the catalyst stream to the riser “II” (21). The cracking reaction is performed in the riser “II” (21) using a highly active catalyst at a temperature of 540 ° C. to 600 ° C.

  In the intermediate severity riser “III” (28), DO (58) contacts the hot regenerated catalyst coming from the regenerator (25) via the tube, ie the standpipe (27). The regenerated catalyst is initially carried by a “lift” fluid (60), which is generally a flow that helps raise the catalyst flow to the riser “III” (28).

  The cracking reaction is carried out in the riser “III” (28) at a temperature of 530 ° C. to 560 ° C. with the same highly active catalyst used in the riser “II” (21). In addition, if this method is applied primarily to refineries that already have two converters (both of which process the feed), converter "B" (20) consists of heavy gas oil or atmospheric residue (AR) Expected to inject raw material (50b), or a mixture of these streams, into disperser (30) of riser "III" (28) while recycling DO (58) of converter "A" (1) Is done. The raw material (50b) of converter “B” (20) may be the same as that used in converter “A” (1) or even an isolated batch of a different quality than the raw material (50a). .

  Alternatively, it can comprise an independent disperser combination of feed (50b) and DO (58). When the operation mode corresponding to the maximum gasoline is set, the converter “A” (1) starts the generation of the already standardized naphtha, and this flow is used as the riser of the converter “B” (20). There is no need to re-disassemble with "II" (21). In this case, the disperser (35) is the same as that used in the riser “III” (28) of the converter “A” (1) and converter “B” (20), or even the raw material ( Of converter “B” (20) to cracked feed (50c) containing heavy gas or atmospheric residue (AR) or a mixture of these streams, which may be an isolated feed of a quality different from 50a) and (50b) It is provided on the riser “II” (21).

  The reaction product (61) of the converter “B” (20) is fed from a middle column of a low quality LCO (65) tower used as a refinery fuel oil distillate from a fractionation tower “B” ( 31). From the top of fractionation column “B” (31), a light hydrocarbon stream (62) exits, is condensed and subsequently sent to the top vessel (32), comprising a stream mainly containing components in the FG and LPG range ( 63). The unstabilized naphtha stream (64) exits the bottom of the container (32). Sending streams (63) and (64) to the gas recovery section facilitates the separation of FG and LPG and the stabilization of naphtha that can later be incorporated into the refinery gasoline pool.

  From the bottom of the fractionation tower “B” (31), the market value is higher than that of fuel oil, and the main industrial application is the production of carbon black. After higher degradation in the riser “III” (28), which allows its normalization as a group residue (DO corresponding to RARO), a higher aromatic content in the composition of DO (66 )coming out.

  If the design is directed to a new unit (no separate gas recovery unit for each converter), the wet gas fraction (54) exiting the top vessel (12) of converter "A" (1) “B” (20) can join the fraction of wet gas (63) exiting from the top vessel (32) and proceed to a common gas recovery section.

  Converter “A” (1) operates with a short contact time in the range of 0.2 to 1.5 seconds (preferably 0.5 to 1.0 seconds) in riser “I” (2), and in LCO For the purpose of minimizing the aromatic content and improving its quality, an appropriate catalyst for maximizing LCO is used. These reaction products (52) are sent to fractionator "A" (11) to remove LCO stream (57) with quality suitable for blending into a feed pool for diesel hydroprocessing. Is done. The non-standardized naphtha (NNE) (55) and DO (58), both of which are removed from the fractionator “A” (11), are for the first riser to decompose NNE (55). A converter “B” having two independent risers: riser “II” (21) and riser “III” (28), the second riser being for disassembling DO (58) Sent. In the separator vessel (22), the risers “II” (21) and “III” (28) are fast separations proposed in the Applicant's patent PI 0704443-7, which is incorporated herein by reference. Linked to the system.

  Converter “B” (20) has a highly active catalyst system suitable for cracking NNE (55) and DO (58), which has two separate risers, so that the reaction temperature of each riser is reduced. , The most recommended range for maximizing the decomposition of each of the streams, namely 530 ° C. to 560 ° C. for the riser “III” (28) for DO (58) and the riser “for NNE (55)” II ”(21) can be set according to 540 ° C. to 600 ° C.

  In addition to using three separate risers to crack the feed (50a) and the NNE (55) and DO (58) streams produced by converter "A" (1), different catalyst systems The desired result, ie maximum production of LCO for the diesel pool (57), minimum of the fuel oil (65) which is LCO used as diluent due to lack of quality for the diesel pool The ideal conditions for optimizing the production of naphtha with a limit suitable for the production and the gasoline pool (64) are obtained. Furthermore, the use of a short contact time in converter “A” (1) results in a stream of LCO (57) with sufficient quality for blending into a diesel pool based on the use of higher reaction temperatures, and thus more All the benefits associated with high TRX use can be exploited. The final result was interpreted as increased operational reliability and favorable thermal balance, opening room for raising the batch temperature and treating residual feedstock.

  This method can be used for new units, as described in FIG. 1, but is also perfectly suitable for improvements over existing units where FCC units already exist for refinery operation. The converter can be in low severity conditions for cracking heavy vacuum gas oil (HVGO) feedstock (50a), as in the example of converter “A” (1). NNE (55) and DO (58) removed from fractionator "A" (11) are sent to a new converter "B" (20) with two risers. A new fractionation column “B” (31) is provided to receive the reaction product (62) from the converter “B” (20). The existing gas recovery section has not changed much and is suitable for receiving fuel gas (FG) and liquefied petroleum gas (LPG) produced by both converters. Another possible application of the method described in FIG. 1 is for a refinery that is installed in the industrial park and already has two independent FCC units, at least one of which has two risers. In this case, a converter having a single riser as in the example of the converter “A” (1) is set to a low severity condition, and the fractionation column “A” as in the example of the converter “B” (20). An interconnection of NNE (55) and DO (58) that is removed from (11) and sent to a second converter with two existing risers may be established. The interconnection between the low severity converter “A” wet gas flow (54) and the high severity converter “B” wet gas flow (63) allows two existing cold sections to be It becomes possible to accommodate the FG and LPG generated by the converter.

  The embodiment shown in FIG. 1 is a preferred embodiment of this method to provide the benefit of independently re-disassembling the naphtha and DO produced by the low severity converter, but both have one riser. It is also possible to apply the present invention to a refinery having only two FCC units. In this case, and if no improvement over existing units is selected, especially when including a new riser design for the converter, the scheme proposed in FIG. It is an alternative method to do.

  The content of the process for converter “A” (1) and fractionator “A” (11) of FIG. 2 is the same as is done in the scheme of FIG.

  However, in FIG. 2, NNE (55) and DO (58) are re-disassembled in the same riser (41) of converter "B" (40). In this case, the naphtha (55) is injected into the disperser (47) at the base of the riser pipe (41) close to the arrival point of the regenerated catalyst coming through the stand pipe (46) of the regenerator (45). In the case of a single riser for the second converter, this increases the DO / batch injection upstream to reduce the effective catalyst / naphtha ratio for the same catalyst cycle to increase the hydrocarbon flow rate. Because the temperature of the mixture (catalyst + naphtha) is higher and the naphtha presents a higher catalyst / naphtha at the base, the riser severity is the highest point, making it ideal for naphtha Position. DO (58) is injected into a dispersion nozzle (48) located above the NNE (55) injection. In addition, the feedstock (50b) processed by the refinery with converter “B” (40) can be continuously cracked by injecting it with the DO (58) into the disperser (48). Alternatively, it can be provided with an independent disperser combination for feed (50b) and DO (58).

  Converter “B” (40) comprises a riser (41), a separator vessel (42), a rectification column (43), a spent catalyst standpipe (44), a regenerator (45), a regeneration And a catalyst stand pipe (46).

  The reaction product (68) of converter “B” (40) is fractionated from the middle of a low quality LCO (72) tower that will later be used as a refinery fuel oil diluent. Sent to “B” (33). From the top of fractionation column “B” (33), a light hydrocarbon stream (69) exits and is condensed and subsequently sent to the top vessel (34), comprising a stream mainly containing components in the FG and LPG range (70). ) Is generated. Unstabilized naphtha stream (71) exits the bottom of the container. Sending streams (70) and (71) to the gas recovery section facilitates the separation of FG and LPG and the stabilization of naphtha that can be subsequently blended into the refinery gasoline pool.

  From the bottom of fractionation tower “B” (33), there is a residual product with a higher aromatic and polyaromatic hydrocarbon content, which has a greater market value than fuel oil and its main industrial application is the production of carbon black. DO (73) with higher aromatic content in its composition after re-decomposition with higher severity in the riser (41) allowing its normalization as an aromatic residue (DO corresponding to RARO) coming out.

  The wet gases (54) and (70) of converter "A" (1) and converter "B" (40), respectively, allow the two existing cold sections to handle a full wet gas stream without requiring major changes. In effect, they are interconnected.

  Converter “B” (40) has a highly active catalyst system suitable for cracking NNE (55) and DO (58), but does not have two separate risers, so for each stream. Lack the flexibility to independently observe the reaction temperature. Considering that naphtha is injected into the base of the riser (41) and is therefore exposed to greater severity, the riser (41) has a temperature of 530 ° C to 570 ° C to facilitate the conversion of DO. Need to work with.

  1 and 2, the flow of the catalyst / oil reactive mixture is shown as an upflow (in the riser). However, Applicants can alternatively use the method and apparatus for accomplishing the above decomposition reaction in the patent of WO 2005/080531 (incorporated herein by reference in its entirety). It has the technology of downflow of its catalyst / oil reactive mixture based on.

  FIGS. 1 and 2 do not show “quenching” injection with a cooling fluid, such as water, and an alternative that can be used for this method as described in patent PI 0504854-0 is the riser tube. The point above the batch injection in either is shown. Another design not illustrated in FIGS. 1 and 2 is to produce additional fractions in heavy naphtha (HN) and light cycle oil (HCO) fractionation towers, It is possible to bring a higher degree of control flexibility between the quality of refinery end derivatives.

  The block diagram according to FIG. 3 shows the application of this new technology to a refinery equipped with an existing FCC. The scheme shows a new technology that involves feeding a raw material (50a) such as heavy vacuum light oil (HVGO) into an existing converter “A” (1). At the output of the converter “A” (1), a reaction product (52) is generated that proceeds to the existing fractionator “A” (11). The reaction product (52) of converter “A” (1) is a lighter hydrocarbon than feed (50a), such as decanted oil (DO) in addition to gasoline, LPG, fuel gas (FG) and LCO. These are sent to fractionator "A" (11) to remove LCO stream (57) having a quality suitable for blending into a diesel pool.

  A non-standardized naphtha stream (NNE) (55) and another DO stream (58), and a wet gas stream (54) primarily comprising FG and LPG are also separated by fractionation column "A" (11). . The flow of NNE (55) and DO (58) proceeds to a new converter “B” (20) with two risers. The reaction product (61) passes through the converter “B” (20) and then proceeds to a new fractionation column “B” (31), where the wet gas fraction (63) mainly containing FG and LPG is converted into the converter “B”. A ”(1) joins the wet gas (54) and proceeds to the existing gas recovery section (36). The second fraction leaving fractionator “B” (31) contains an unstabilized naphtha stream (64) that also goes to the gas recovery section (36) and is involved in moisture absorption and is stable. After conversion, proceed to refinery petrol pool. Two more fractions are the low quality and high aromatic content LCO corresponding to the diluent (65) and the DO fraction corresponding to the aromatic residue (DO corresponding to RARO) (66). , Produced from this fractionator “B” (31).

  After passing through the gas recovery unit (36), FG (74), LPG (75) and gasoline (76) fractions are generated.

  The following examples illustrate the operation and manufacturing profile of this method, but they should not be construed as limiting other operating conditions.

(Example 1)
In this example, converter “A” (1) operates on HGO (heavy gas oil) feedstock (50a) at a reaction temperature of 520 ° C. and a contact time of 0.5 seconds, and yields the following yield profile: give.

In the converter “B” (20), the naphtha (55) and DO (58) coming from the converter “A” (1) are connected to the 580 ° C. riser “II” (21) and the 535 ° C. riser “III”, respectively. Re-disassemble at (28). The following yield profile is obtained:

These data make it possible to calculate the overall yield of the unit. The following table compares the results of this method with a typical FCC yield profile.

  As will be appreciated, in this case it is operating for the purpose of middle distillate, but FG and LPG yields can be recovered (if the FCC unit is improved, the same existing gas recovery unit can be used) ). The gasoline yield is reduced by about 15% as desired, contributing to reducing this excess of fuel in the market (this time, if gasoline demand increases seasonally, the feed (50a) is converted Can be easily reversed by injecting into the lower disperser (9) of "A" (1) and adjusting the FCC mode of operation to full gasoline). While the contribution of FCC units to the diesel pool is significantly increased, fuel oil production is minimized through marketing of DO produced as aromatic residues (RARO).

  The following examples illustrate the benefits of using short contact times in the riser as a way to reduce reaction severity in converters operated towards the production of LCO for diesel.

(Example 2)
In this embodiment, three operation scenarios of the converter “A” (1) obtained from an experiment performed on the FCC unit prototype of the applicant will be described.

  Experiment “A” represents an example of basic operation using a highly active catalyst and TRX at 530 ° C. Experiments “B” and “C” represent means (routes) for reducing reaction severity that are different from the basic example. In both cases, the severity is reduced by using a low activity catalyst and adjusting the operating conditions. However, they use different processing variables for adjustment. Experiment “B” shows the TRX reduction means, while experiment “C” shows the contact time reduction means.

The main results are shown in the table below.

  It can be seen at a glance that both means (“B” and “C”) were good at reducing the conversion rate and consequently producing better quality LCO compared to the basic example.

  Both experiments are shown at the same dense phase temperature based on the adjustment of the raw material temperature in each experiment. In experiment “B” (TRX reduction means), the high-density phase temperature tended to increase compared to the basic example, and it had to be corrected by reducing the raw material temperature from 80 ° C. It becomes possible to confirm. Next, in Experiment “C” (contact time shortening means), conversely, the high-density phase temperature of the regenerator that can be used to increase the raw material temperature to 120 ° C. tended to decrease.

  Directly paying attention to the coke yield as a result of the adjustment of the thermal equilibrium and the raw material temperature in each scenario, it can be seen that there is a difference of 15% in coke generation even in the TRX reduction means compared with the basic example. This difference is due to the replacement of high activity catalyst items (more likely to form coke or larger delta coke) because low activity (smaller delta coke) is suitable for low conversion operation. . The use of a low activity catalyst for thermal equilibrium serves to reduce the dense phase temperature. However, in Experiment “B”, much of this benefit is lost due to the high density phase heating tendency of the regenerator due to the small TRX in the riser.

  In experiment “C”, the difference in coke generation is 35% compared to the base example, which is significantly higher than that obtained by experiment “B”. This occurs because the short contact time means allows full utilization of the full cooling of the dense phase temperature achieved by replacing the catalyst in the unit.

  The benefit of using a short contact time is most apparent when comparing the results of experiments “B” and “C” (two experiments using the same catalyst). Both experiments achieve the same conversion rate and production level, and LCO quality. However, in experiment “C” there is a sufficient thermal difference to raise the raw material temperature to 200 ° C. for the same dense phase temperature. This allowed for a 25% lower coke generation than experiment “B” despite the higher TRX (increasing converter coke demand) in experiment “C”. This exemplifies a method of using thermal insulation provided by the short contact time means. Increasing the temperature of the raw material reduces the coke demand for the converter without using a portion of the combustion blower air. Using this excessive air from the blower, it is possible to increase the raw material flow rate of the unit without investing in the regeneration part of the converter. Comparing experiment “B” and experiment “C”, it can be seen that the reduction in TRX does not result in the same difference and the widening of the operating window afforded by the reduction in contact time.

  This example (according to the same conversion rate and the same LCO quality experiments “B” and “C”) shows that the use of the short contact time / high TRX combination compared to the long contact time / low TRX combination It demonstrates the excellent thermal balance of the unit. The combination of short contact time / high TRX in an industrial unit provides the benefits described above in addition to allowing for increased raw material temperatures. It improves operational reliability by reducing coke deposits in the reaction and rectification unit equipment and allows for the treatment of residual feedstock in the unit.

  Although contact time is a variable cited in the literature as one of the possible variables for adjusting the reaction severity, it is described in the literature by acting at higher reaction temperatures. That all middle distillate FCC processes follow the line of TRX reduction (using the converter operating to produce middle distillate) and still get all the benefits from using the short contact time / high TRX combination. Techniques using short contact times that make it possible are not found in the literature. The approach that Applicants learned through the development of its FCC method for maximizing diesel is a central aspect of the present invention that leads to a new riser design philosophy of the FCC unit that includes examples of maximum LCO operation. .

  Therefore, the contact time variable is of critical importance in this method. By installing the raw material injector at the highest position of the riser, the existing unit can be optimized for maximum LCO operation. For new units designed for activities set between maximum LCO or maximum gasoline, all benefits of using higher TRX (advantageous thermal balance and operational reliability) even at maximum LCO activity The use of injection devices at different reactor heights (giving the unit flexibility) will be considered.

FCC is one of the major producers of gasoline in refineries, and in a situation where the market for this derivative is shrinking, the diesel market is expanding, and the standards for diesel quality are also improving. The development of FCC processes that help offset gasoline and fuel oil surpluses in markets where there is a shortage is of strategic importance and essential for refineries to maintain full capacity. These are issues that the present invention addresses to meet.
Various aspects that can be included in the present invention are summarized as follows.
[1].
Converter "A" (1) operating at low severity and converter "B" (20) operating at high severity for the purpose of producing the best quality LCO blended in refinery diesel pools FCC method to maximize diesel, including
With the aim of adjusting the production and quality profiles of other products of the above method to achieve reduced fuel oil production, gasoline standardization and LPG recovery from products in converter “B” (20) , Converter “A” (1) so that converter “B” (20) receives the non-standardized naphtha (NNE) (55) and decanted oil (DO) (58) generated by converter “A” (1). ) And “B” (20) operate in harmony.
[2].
The diesel of claim 1 above, wherein the feed (50a) for converter “A” (1) contains heavy diesel oil from distillation, heavy diesel oil from coke, or atmospheric residue, or a mixture of these streams. FCC method to make it.
[3].
To maximize diesel according to claim 1 above, wherein the feed (50b) for the second converter comprises heavy gas oil from distillation, heavy gas oil from coke, or atmospheric residue, or a mixture of these streams. FCC method.
[4].
Converter “A” (1) includes riser “I” (2), separator vessel (3), rectification column (4), and regenerator (6), where the catalyst is a rectification column ( The diesel according to claim 1, which flows to the regenerator (6) through the stand pipe (5) of 4) and flows to the riser pipe "I" (2) through the stand pipe (7) of the regenerator (6). FCC method for maximizing energy consumption.
[5].
Batch-catalyst contact in riser “I” (2) with low severity in converter “A” (1) ranging from 0.2 to 1.5 seconds, preferably 0.5 to 1.0 seconds The FCC process for maximizing diesel as described in 1 above with the use of time.
[6].
Converter “B” (20) includes riser “II” (21), riser “III” (28), separator vessel (22), rectification column (23), and regenerator (25). And the catalyst flows to the regenerator (25) through the stand pipe (24) of the rectification column (23), and rises “II” (21 through the stand pipe (26) of the regenerator (25). ) And through the standpipe (27) of the regenerator (25) to the riser "III" (28), which is a preferred embodiment for the converter "B" (20) FCC method to maximize diesel.
[7].
The feed (50c) injected into the riser "II" (21) of the converter "B" (20) is heavy gas oil from distillation, heavy gas oil from coke, or atmospheric residue, or a mixture of these streams An FCC process for maximizing diesel as described in 1 above.
[8].
Converter “B” (40) alternatively includes a single riser (41), separator vessel (42), rectification column (43), and regenerator (45), with the catalyst 2. The flow of claim 1 wherein the separator vessel (42) flows to the regenerator (45) via the stand pipe (44) and flows to the riser pipe (41) via the regenerator (45) stand pipe (46). FCC method to maximize diesel.
[9].
Item 1 above wherein the converters “A” (1) and “B” (20) produce reaction products that proceed to different fractionation columns, ie fractionation columns “A” (11) and “B” (31), respectively. FCC method to maximize diesel described in
[10].
9. Diesel according to 1 and 8 above, wherein converters “A” (1) and “B” (40) produce reaction products that proceed to fractionation columns “A” (11) and “B” (33), respectively. FCC method for maximizing energy consumption.
[11].
In the converter “A” (1), the raw material (50a) is injected (in maximum LCO operation) into the disperser (8) at a higher position than the low severity riser “I” (2) and, optionally, the riser Injected into the disperser (9) at the base of "I" maximizes diesel according to items 1 to 6 above, giving the refinery the flexibility to change to maximum gasoline mode FCC method for
[12].
The above, wherein the cracking reaction in the riser “I” (2) is carried out at a temperature of 510 ° C. to 560 ° C., preferably 530 ° C. to 550 ° C., using a low activity catalyst suitable for maximizing LCO. FCC method for maximizing diesel as described in paragraphs 1-6.
[13].
The reaction product (52) of converter “A” (1) is a lighter hydrocarbon than the feed (50a), such as gasoline, LPG, fuel gas (FG) and LCO plus decanted oil (DO), Items 1 to 6 and 9 above, where these are sent to fractionation tower "A" (11), from which a suitable quality LCO stream (57) is removed for blending into a diesel pool. FCC method to maximize diesel power.
[14].
At the top of fractionation tower “A” (11), a stream of wet gas (54) and a stream of non-standardized naphtha (NNE) (55) are generated and separated into top vessel (12) above. FCC method for maximizing diesel as described in paragraphs 9 and 9.
[15].
The NNE fraction (55) is sent to the base of the high severity riser “II” (21) that forms part of the second converter “B” (20), or the NNE fraction (56) FCC for maximizing diesel according to 1 to 6 above, sent to the "lift" part of the riser "I" (2) forming part of the first converter "A" (1) Law.
[16].
The NNE fraction (55) is sent to the base (high severity part) of the riser (41) that forms part of the second converter “B” (40), or the NNE fraction (56) 9. FCC for maximizing diesel according to 1 and 8 above, sent to the “lift” part of the riser “I” (2) forming part of the first converter “A” (1) Law.
[17].
1 to 6 above, wherein the DO stream (58) exits from the bottom of fractionator "A" (11) and is sent to the base of riser "III" (28) of converter "B" (20) and The FCC method for maximizing diesel as described in item 9.
[18].
Disperser (47) for DO stream (58) exiting the bottom of fractionator "A" (11) and injecting NNE (55) into the riser (41) of converter "B" (40) 11. An FCC process for maximizing diesel as described in paragraphs 1, 8 and 10 above, which is sent to a disperser (48) located above.
[19].
Item 1. The reaction product (61) of converter "B" (20) is sent to fractionation tower "B" (31), from which an LCO stream (65) corresponding to the fuel oil diluent exits. FCC method to maximize diesel power.
[20].
The reaction product (68) of converter “B” (40) is sent to fractionation tower “B” (33), from which the LCO stream (72) corresponding to the fuel oil diluent exits 1, 8, and 11. FCC method for maximizing diesel according to item 10.
[21].
A wet gas stream (63) and an unstabilized naphtha stream (64) of quality corresponding to gasoline are produced at the top of fractionation tower "B" (31) and separated into a top vessel (32). 10. FCC method for maximizing diesel according to items 1 to 6 and 9 above.
[22].
A wet gas stream (70) and an unstabilized naphtha stream (71) having a quality corresponding to gasoline are produced at the top of fractionation tower "B" (33) and separated into a top vessel (34). The FCC method for maximizing the diesel described in the above items 1, 8, and 10.
[23].
A DO (66) having a specification corresponding to an aromatic residue (DO corresponding to RARO) is produced at the top of the fractionating column “B” (31), as described in paragraphs 1 to 6 and 9 above. FCC method to maximize diesel.
[24].
11. Diesel according to paragraphs 1, 8, and 10 above, wherein DO (73) (DO corresponding to RARO) having specifications corresponding to aromatic residues is produced at the bottom of fractionation tower "B" (33). FCC method to maximize.
[25].
When the fraction of wet gas (63) exiting from the top (32) joins the flow (54) of wet gas from the converter “A” (1) and proceeds to or is present in a common gas recovery section Is the FCC method for maximizing diesel according to 1 and 21 above, which proceeds to two different gas recovery units.
[26].
When the fraction of wet gas (70) exiting from the top (34) merges with the flow of wet gas (54) from the converter "A" (1) and goes to a common gas recovery section or is present 23. FCC method for maximizing diesel as described in 1 and 22 above, proceeding to two different gas recovery units.
[27].
Non-standardized naphtha (NNE) (55) and decanted oil (58), both removed from fractionator “A” (11), are added to riser “II” (21) and riser “III” (28). Converter “B” having two independent risers, the first riser for disassembling NNE (55) and the second riser for disassembling DO (58) The FCC method for maximizing diesel according to paragraphs 1 to 6 and 9, above, sent for re-decomposition in (20).
[28].
Non-standardized naphtha (NNE) (55) and decanted oil (58), both removed from fractionator “A” (11), decompose NNE (55) at its “lift” section and DO (58) FCC for maximizing diesel as described in paragraphs 1, 8 and 10 above for re-cracking in converter "B" (40) with a single riser (41) Law.
[29].
Converter “B” (20) processes fresh feed (50b) at the same disperser (30) used for DO (58) or at another disperser level in riser “III” (28) An FCC process for maximizing diesel as described in paragraphs 1 to 6 above with an alternative to.
[30].
Converter “B” (40) is an alternative to processing new feed (50b) at the same disperser (48) used for DO (58), or at another disperser level in the riser (41). 9. An FCC process for maximizing diesel as described in 1 and 8 above.
[31].
When changing the operation mode of the converter “A” (1) to maximize gasoline, the converter “B” (20) is replaced with new raw material (35) in the same disperser (35) of the riser “II” (21). FCC process for maximizing diesel according to paragraphs 1 to 6 above with an alternative to treating 50c).
[32].
Converter “B” (20) is suitable for cracking NNE (55) and DO (58), and the low activity catalyst used in converter “A” (1) to crack feed (50a) 7. An FCC process for maximizing diesel according to items 1 to 6 above having a highly active catalyst system different from the system.
[33].
Converter "B" (40) is suitable for cracking NNE (55) and DO (58), low activity catalyst used in converter "A" (1) to crack feedstock (50a) 7. An FCC process for maximizing diesel according to items 1 to 6 above having a highly active catalyst system different from the system.
[34].
By including two independent risers in converter “B” (20), each reaction temperature is adjusted according to the most recommended range, and the flow of NNE (55) and DO (58) in each of them is adjusted. 7. FCC process for maximizing diesel according to claims 1 to 6 above, which makes it possible to maximize cracking and is a preferred embodiment for cracking these streams.
[35].
FCC process for maximizing diesel according to paragraphs 1 to 6 above, wherein the riser “II” (21) operates at a reaction temperature of 540 ° C. to 600 ° C.
[36].
7. FCC process for maximizing diesel according to paragraphs 1 to 6 above, wherein the riser “III” (28) operates at a reaction temperature of 530 ° C. to 560 ° C.
[37].
Operates at reaction temperatures from 530 ° C. to 570 ° C., single rise where NNE (55) is decomposed at the “lift” part of the base of the riser (41) and DO (58) is decomposed at a higher point 9. FCC method for maximizing diesel according to paragraphs 1 and 8 above, wherein the tube (41) is included in the converter “B” (40).
[38].
A riser “III” (28) for re-decomposing DO (58) operates at high reaction temperatures and long contact times to meet the objective of reducing DO production, but with some amount of lower quality 7. An FCC process for maximizing diesel as described in 1 to 6 above to produce LCO (65).
[39].
The riser (41) for re-decomposing NNE (55) and DO (58) operates at high reaction temperatures and long contact times to meet the objective of reducing DO production, but with some amount of lower 9. FCC process for maximizing diesel according to 1 and 8 above, producing quality LCO (72).
[40].
The lower quality LCO (65) produced by re-decomposing DO (58) in converter "B" (20) results in lower severity raw material (50a) decomposition in converter "A" (1). 7. FCC process for maximizing diesel according to items 1 to 6 above, isolated from the high quality LCO (57) produced in
[41].
The lower quality LCO (72) produced by re-disassembling DO (58) along with NNE (55) in the riser (41) of converter "B" (40) is in converter "A" (1). 40. FCC process for maximizing diesel according to paragraphs 1, 8 and 39 above, isolated from high quality LCO (57) produced by cracking of raw material (50a) at low severity.
[42].
The FCC method for maximizing diesel according to claim 1, comprising a gas recovery section (36) from which a fraction of fuel gas (74), LPG (75) and gasoline (76) is produced.
[43].
The FCC process for maximizing diesel according to claim 1 wherein the flow of reactive catalyst / oil mixture in any of the converters is downward.
[44].
The FCC method for maximizing diesel as described in the above item 1, which can be applied to an existing FCC unit.

Claims (46)

Converter “A” (1) operating at low severity for the purpose of producing the best quality LCO blended in a refinery diesel pool, supplied from converter “B” (20 or 40) Converter "A" (1) having riser pipe "I" (2) for contacting the product and catalyst, and converter "B" (20 or 40) operating at high severity, wherein converter "A" A FCC process for maximizing diesel, comprising a converter “B” (20 or 40) having a riser “II” (21 or 41) for contacting the feed from the catalyst with the catalyst. And
Converter "B" (20 or 40) Converter "A" (1) a portion of the separated naphtha in the fractionating column "A" (11) from the reaction product produced (52) in (55) and Dekanteddo In order to adjust the quality of the LCO (57), which is the product that receives the oil (DO) (58) and is separated in the fractionation tower "A" (11), the riser of the converter "A" (1) "I" (2), above Symbol FCC process Ru accept the other parts of the naphtha that has been sent back there in (56).   The FCC process for maximizing diesel according to claim 1, wherein the feed (50a) for converter "A" (1) comprises heavy gas oil from distillation, or atmospheric distillation residue, or a mixture of these streams. .   The FCC process for maximizing diesel according to claim 1, wherein the feed (50b) for converter B (20) comprises heavy light oil from distillation, or atmospheric distillation residue, or a mixture of these streams. Converter “A” (1) includes riser “I” (2), separator vessel (3), rectifying tower (4), and regenerator (6), and the catalyst is rectifying tower (4). The diesel according to claim 1 flows to the regenerator (6) through the standpipe (5) and flows up to the riser "I" (2) through the standpipe (7) of the regenerator (6). FCC method to limit. Claim 1 wherein low severity in converter "A" (1) involves the use of charge and catalyst contact time in riser "I" (2) in the range of 0.2 to 1.5 seconds. FCC method for maximizing the described diesel. Converter “B” (20) includes riser “II” (21), riser “III” (28), separator vessel (22), rectification tower (23), and regenerator (25). And the catalyst flows to the regenerator (25) via the standpipe (24) of the rectifier tower (23) and to the riser “II” (21) via the standpipe (26) of the regenerator (25). The FCC process for maximizing diesel according to claim 1, wherein the flow flows through the standpipe (27) of the regenerator (25) to the riser "III" (28).   The feedstock (50c) injected into the riser "II" (21) of the converter "B" (20) comprises heavy gas oil from distillation, or atmospheric distillation residue, or a mixture of these streams. FCC method for maximizing the described diesel. Converter “B” (40) includes a single riser pipe (41), separator vessel (42), rectifier tower (43), and regenerator (45), where the catalyst is separator vessel (42). ) To the regenerator (45) via the standpipe (44) and to the riser (41) via the standpipe (46) of the regenerator (45) FCC method to do.   Converters "A" (1) and "B" (20) produce reaction products that proceed to different fractionation columns, ie fractionation columns "A" (11) and "B" (31), respectively. The FCC method for maximizing the diesel according to any one of items 1 to 6.   Converters "A" (1) and "B" (40) produce reaction products that proceed to fractionation columns "A" (11) and "B" (33), respectively. FCC method for maximizing the diesel described in the paragraph.   In the converter “A” (1), the raw material (50a) is injected into the disperser (8) at a position above the low severity riser pipe “I” (2) and, optionally, in the riser “I” FCC process for maximizing diesel according to any one of claims 1 to 6, which is injected into the disperser (9) of the base.   Converter “A” (1) has riser “I” (2) in which the cracking reaction uses a low activity catalyst suitable for maximizing LCO The FCC method for maximizing diesel according to any one of claims 1 to 6, wherein the FCC method is performed at a temperature of 510 ° C to 560 ° C.   The reaction product (52) of converter “A” (1) is a lighter hydrocarbon than the feed (50a), such as gasoline, LPG, fuel gas (FG) and LCO plus decanted oil (DO), Any of claims 1 to 6 and 9 wherein these are sent to a fractionation tower "A" (11) from which a suitable quality LCO stream (57) is removed for blending into a diesel pool. The FCC method for maximizing diesel as described in item 1.   At the top of fractionator “A” (11), a wet gas stream (54) and a naphtha (55) stream are produced and separated into a top vessel (12), where the top vessel (12) A container for collecting a fraction obtained from the top of the distillation column "A" (11), wherein each of the wet gas (54) and the naphtha (55) is separated from the top container (12). FCC method to maximize diesel described in   The naphtha fraction (55) is sent to the base of the high severity riser “II” (21) that forms part of the second converter “B” (20), or the naphtha fraction (56) It is sent to the “lift” part of the riser pipe “I” (2) that forms part of the first converter “A” (1) (where the naphtha fraction (56) is combined with the flow above the catalyst). The FCC method for maximizing diesel according to any one of claims 1 to 6.   The naphtha fraction (55) is sent to the base (high severity part) of the riser (41) that forms part of the second converter “B” (40), or the naphtha fraction (56) , The “lift” part of the riser pipe “I” (2) that forms part of the first converter “A” (1) (where the naphtha fraction (56) is combined with the flow above the catalyst). 9. An FCC process for maximizing diesel according to any one of claims 1 and 8.   DO stream (58) exits the bottom of fractionator "A" (11) and is sent to converter "B" (20), where converter "B" (20) is connected to riser "II" In addition to (21), it has a riser “III” (28) for contacting the catalyst with another feed from converter “A”, where fractionator “A” (11) , Fractionating the reaction product containing naphtha (55) and decanted oil (DO) (58) produced by converter "A" (1) to produce DO stream (58) from the bottom thereof. 10. The FCC method for maximizing diesel according to any one of claims 1 to 6 and 9.   Disperser (47) for DO stream (58) exiting from the bottom of fractionator "A" (11) and injecting naphtha (55) into the riser (41) of converter "B" (40) Where the fractionation tower “A” (11) contains the decanted oil (DO) (58) produced in the converter “A” (1). 11. The FCC process for maximizing diesel according to any one of claims 1, 8 and 10, wherein the product is fractionated to produce a DO stream (58) from its bottom.   The reaction product (61) of converter "B" (20) is sent to fractionation tower "B" (31) from which an LCO stream (65) corresponding to the fuel oil diluent exits. FCC method to maximize diesel power.   The reaction product (68) of converter "B" (40) is sent to fractionation tower "B" (33), from which an LCO stream (72) corresponding to the fuel oil diluent exits. And FCC method for maximizing diesel according to any one of 10 above.   Wet gas stream (63) and naphtha stream (64) are produced at the top of fractionation tower "B" (31) and separated into top vessel (32), where top vessel (32) A container for collecting a fraction obtained from the top of the distillation column “B” (31), wherein each of the wet gas (63) and the naphtha stream (64) is separated from the top container (32). Item 10. The FCC method for maximizing diesel according to item 9.   A wet gas stream (70) and a naphtha stream (71) are produced at the top of fractionation tower "B" (33) and separated into a top vessel (34), where the top vessel (34) A vessel for recovering a fraction obtained from the top of the distillation column “B” (33), wherein each of the wet gas (70) and the naphtha stream (71) is separated from the top vessel (34). Item 15. The FCC method for maximizing the diesel according to item 10.   10. Diesel as claimed in claim 9, wherein a DO (66) with specifications corresponding to aromatic residues (DO corresponding to RARO) is produced at the bottom of fractionation tower "B" (31). FCC method for   The diesel according to claim 10, wherein DO (73) (DO corresponding to RARO) with specifications corresponding to aromatic residues is produced at the bottom of fractionation tower "B" (33). FCC method for   When the fraction of wet gas (63) exiting the top vessel (32) merges with the flow of wet gas (54) from converter “A” (1) and proceeds to a common gas recovery section or is present 23. The FCC method for maximizing diesel according to claim 21, which proceeds to two different gas recovery units.   When the fraction of wet gas (70) exiting the top vessel (34) merges with the flow of wet gas (54) from the converter "A" (1) and proceeds to a common gas recovery section or is present 23. The FCC process for maximizing diesel according to claim 22, wherein the process proceeds to two different gas recovery units.   Naphtha (55) and decanted oil (58), both removed from fractionator "A" (11), are two separate risers, riser "II" (21) and riser "III" (28). At converter "B" (20), wherein the first riser is for disassembling naphtha (55) and the second riser is for disassembling DO (58) Sent to re-cracking, where fractionator “A” (11) is a reaction product comprising naphtha (55) and decanted oil (DO) (58) produced in converter “A” (1) 10. The FCC process for maximizing diesel according to any one of claims 1 to 6 and 9, wherein the product is fractionated to produce a DO stream (58) from the bottom thereof.   Naphtha (55) and decanted oil (58), both removed from fractionator "A" (11), are combined with naphtha (55) in its "lift" section (naphtha (55) with the flow above the catalyst. The diesel according to claim 10, wherein the diesel is sent for re-disassembly in a converter "B" (40) with a single riser (41) that disassembles at a point and disassembles DO (58) at the top FCC method to limit.   Claim that converter "B" (20) processes fresh feed (50b) at the same disperser (30) used for DO (58) or at another disperser level in riser "III" (28) Item 7. The FCC method for maximizing diesel according to any one of Items 1 to 6.   Converter 1 "B" (40) processes fresh feed (50b) at the same disperser (48) used for DO (58) or at another disperser level in the riser (41). 9. FCC method for maximizing diesel according to any one of 8   When changing the operation mode of the converter “A” (1) to maximize gasoline, the converter “B” (20) is replaced with new raw material (35) in the same disperser (35) of the riser “II” (21). The FCC process for maximizing diesel according to any one of claims 1 to 6, which treats 50c).   Converter "B" (20) is suitable for cracking naphtha (55) and DO (58), low activity catalyst used in converter "A" (1) to crack feed (50a) 7. The FCC process for maximizing diesel according to any one of claims 1 to 6, having a highly active catalyst system different from the system.   Converter “B” (40) is suitable for cracking naphtha (55) and DO (58), low activity catalyst used in converter “A” (1) to crack feed (50a) 7. The FCC process for maximizing diesel according to any one of claims 1 to 6, having a highly active catalyst system different from the system.   By including two independent risers in the converter “B” (20), each reaction temperature is adjusted according to the most recommended range to allow the flow of naphtha (55) and DO (58) in each of them. The FCC process for maximizing diesel according to any one of claims 1 to 6, which makes it possible to maximize the decomposition.   The FCC process for maximizing diesel according to any one of claims 1 to 6, wherein the riser "II" (21) operates at a reaction temperature of 540 to 600 ° C.   Converter “B” (20) has riser “III” (28) for contacting the catalyst with another feed from converter “A” in addition to riser “II” (21). The FCC process for maximizing diesel according to any one of claims 1 to 6, wherein the riser "III" (28) operates at a reaction temperature of 530 ° C to 560 ° C.   Operates at reaction temperatures from 530 ° C. to 570 ° C., single rise where naphtha (55) is decomposed at the “lift” portion of the base of the riser (41) and DO (58) is decomposed at a higher point 9. The FCC method for maximizing diesel according to any one of claims 1 and 8, comprising a tube (41) in the converter "B" (40).   Converter “B” (20) has riser “III” (28) for contacting the catalyst with another feed from converter “A” in addition to riser “II” (21). This riser “III” (28) fulfills the purpose of re-decomposing DO (58) and operating at high reaction temperatures and long contact times to reduce the production of DO, but with some amount of lower 9. The FCC process for maximizing diesel according to any one of claims 1 and 8, which produces a quality LCO (65).   A riser (41) for re-decomposing naphtha (55) and DO (58) operates at high reaction temperatures and long contact times to meet the objective of reducing DO production, but with some amount of lower 9. The FCC process for maximizing diesel according to any one of claims 1 and 8, which produces a quality LCO (72).   The lower quality LCO (65) produced by re-decomposing DO (58) in converter "B" (20) results in lower severity raw material (50a) decomposition in converter "A" (1). 9. The FCC process for maximizing diesel according to any one of claims 1 and 8, which is isolated from the high quality LCO (57) produced in the process.   The lower quality LCO (72) produced by re-disassembling DO (58) with naphtha (55) in the riser (41) of converter "B" (40) is in converter "A" (1). 40. FCC for maximizing diesel according to any one of claims 1, 8 and 39 isolated from high quality LCO (57) produced by cracking of raw material (50a) at low severity Law.   The FCC method for maximizing diesel according to claim 1, comprising a gas recovery section (36) from which a fraction of fuel gas (74), LPG (75) and gasoline (76) is produced.   The FCC process for maximizing diesel according to claim 1, wherein the flow of the reactive catalyst / oil mixture in any of the converters is downward.   The FCC method for maximizing diesel according to claim 1, which can be applied to an existing FCC unit. The FCC process for maximizing diesel according to claim 5, wherein the contact time between the charge and the catalyst in the riser "I" (2) is in the range of 0.5 to 1.0 seconds.   The FCC process for maximizing diesel according to claim 12, wherein the cracking reaction in the riser "I" (2) is carried out at a temperature of 530 ° C to 550 ° C.