FR2801603A1 - Process for the production of internal combustion engine fuel, involves catalytic reforming of petrol obtained by direct distillation of crude oil - Google Patents

Abstract

Process for the production of a motor fuel comprising a petrol of determined octane index involves pre-heating a charge comprising a petrol obtained by a direct distillation; catalytic reforming to increase the octane index; separation of the hydrogen produced by the reforming process; and storage of the high octane petrol and/or hydrogen. An Independent claim is included for an installation for conducting the process.

Description

The present invention relates to the technical field of internal combustion engines, for example for a transport vehicle. The object of the present invention is to use as a fuel a petrol of direct distillation of the crude (preferably after desulfurization extraction of the aromatics) and to carry out catalytic reforming reactions upstream engine so as to reach the commercial specifications of a fuel , especially the number of octane. The production of associated hydrogen can be advantageously used in admixture with the reformed gasoline to improve engine combustion performance and help to reduce the discharge. In another embodiment, the hydrogen produced can be used and / or stored to operate. a fuel cell. This last variant thus presents an interest for the mixed vehicles teams of an internal combustion engine and an electric motorization. GB 2159876 is known which describes the principle of reforming to increase the octane number of a gasoline but the embodiment applied to an internal combustion engine is different from that of the present invention.

Also known is US-4884531 which is in the same field but describes almost exclusively improvements in the catalyst formulation.

 Thus, the present invention relates to a device for producing a fuel intended for a motorization, comprising at least gasoline having a determined octane number. The device comprises: means for supplying a charge constituted by a direct distillation gasoline; means for preheating said charge; catalytic means for reforming the charge to increase its octane number up to the determined value; means for separating the hydrogen associated with the reforming reaction, means for storing gasoline of high octane number and / or hydrogen.

The device may comprise distribution means arranged downstream of the separation means for directing the hydrogen to a motorization or storage. Catalytic reforming means may comprise a catalyst fixed bed reactor and injection means upstream of the reactor of a determined amount of the hydrogen produced by the reforming reaction.

Injection means may comprise a suitable compressor providing a predetermined partial pressure of hydrogen in the reactor. Catalytic reforming means may comprise a rotary barrel comprising the catalyst.

barrel can be composed of a set of reactor tubes disposed parallel to the axis of rotation of the barrel, so that each of the tubes carries out a cycle comprising a reaction phase followed by a set of regeneration phases, depending on the rotation said barrel.

In this variant, the catalytic reforming means may comprise means for circulating the various fluids through the reactor tubes, constituted by upper and lower covers of said barrel having orifices for supplying fluids into the tubes for the different phases.

reforming means may comprise means for controlling the temperature of the reactor tubes by means of a casing containing a barrel.

device may comprise means for drying ambient air means for injecting dry air into reactor tubes in the regeneration phase.

The device may also include means for purifying the hydrogen produced by the reforming reaction. The means for drying the air and the means for purifying the hydrogen may comprise molecular sieves.

The sieves may be arranged in a rotating system to effect a cycle of at least three successive phases: adsorption, desorption, cooling.

The engine can be an internal combustion engine.

The engine can be powered by gasoline high octane and possibly by a quantity of hydrogen.

engine exhaust can be recycled to perform at least heat exchange necessary for the catalytic reaction and preheating.

The engine can include an electric motor powered by the energy produced by a hydrogen fuel cell, the hydrogen from the catalytic reforming.

The invention also relates to a process for producing a gasoline having a specified octane number and hydrogen which uses the device described above.

The invention can be advantageously applied to a vehicle embedded system.

In this application, a vehicle may include a combustion engine an electric motor.

The present invention will be better understood and advantages will appear more clearly on reading the following description, the following examples, in no way limiting, illustrated by the figures after appended, among which - Figure 1 schematically shows the architecture of the present invention B>; </ B> - Figure 2 shows an example diagram for a first so-called semi-regenerative variant; FIG. 3 shows the diagram of a second so-called regenerative variant; FIG. 4 describes the principle of a reactor for the regenerative variant; - Figure 5 shows the different phases of reaction and regeneration. ; FIG. 6 illustrates an air drying device. FIG. 7 depicts an example of a hydrogen purification device.

In Figure 1 showing the general scheme of the concept of the present invention, the reference 1 designates the device comprising catalytic reforming means. This device receives a charge via the line 2 which passes through preheating and vaporization system 3 of said load according to the thermal requirements of the downstream catalytic reactions. The heat exchanger 3 at least partially uses the exhaust gases 13 of the internal combustion engine 4 through the duct 5. These exhaust gases are also advantageously used (duct 6) in the reforming device 1. effluent, resulting from the internal conversion to the device 1, is conducted by the line referenced 7 'a separator 8 liquid / gas so as to bring to the engine 4, independently by the line 9, the gasoline increased octane and by the line 10 hydrogen associated with the catalytic reactions of the device 1. At the separator outlet 8, distribution means 11, valve, 3-way distributor equivalent, allow to send hydrogen to a use symbolized by the circle referenced 12. This use can be storage, supply of a hydrogen fuel cell, recycling of hydrogen in the circuit for the maintenance of a minimum partial pressure. Downstream of the distribution 11, the presence of a compressor or a superpressor is possible. reference 14 designates a gas tank with high octane number that can serve as a buffer and relay, especially during the startup phase. associated distribution is not shown here.

The feed is typically a straight-run gasoline (or a Fischer Tropch gasoline). This species was preferentially pretreated with hydrotreatment (HDT) so as to obtain the appropriate S, N specifications for use in catalytic reforming.

The two main reactions of catalytic reforming are: dehydrogenation naphthenes (looped aliphatic compounds) and dehydrocyclization iso and normal paraffins. These two reactions lead to the formation of aromatics which have a very high octane number. These two reactions are highly endothermic and favored by a lowering of the pressure in the reactor. Another important reaction is the isomerization of normal paraffins, since iso paraffins have a higher octane number than normal paraffins. Coke formation is also an associated reaction, but can be reduced by maintaining a sufficient hydrogen partial pressure.

The main advantages of the present invention are of two kinds the interest of hydrogen for a motorization, and the minimization of CO2 emissions.

Hydrogen offers many advantages as a fuel - the combustion of hydrogen is obviously without CO2 emissions; - mixed with other hydrocarbons, it helps to reduce unburned HC emissions by its effect on the overall combustion rate. The speed of propagation of the H2 flame being three times higher than that of gasoline under the same conditions, hydrogen can be considered as an efficient combustion accelerator, opening up certain prospects for use in a lean mixture; it can also be pointed out that the mass ICP of hydrogen is much higher than that of conventional liquid fuels. This effect is however limited by the small amount of hydrogen in relation to the quantity of gasoline; - from the point of view of legislation, the use of straight-run gasoline (or a Fischer Tropch gasoline, especially well adapted to this invention) would make it possible to satisfy the new specification of 1% benzene content by 2000 since a gasoline of first distillation generally does not contain more than 0.5% of benzene and may even be completely deflavored.

- Hydrogen can be the energy source for other energy generators, for example a fuel cell producing electricity for an electric motor of a mixed vehicle.

The C02 release is an extremely important point in the current context of environmental concerns and more particularly those concerning the greenhouse effect. A comparison between the conventional channels (gasoline and gas oil) and the methanol industry was initially carried out at the level of the vehicle itself, and then by integrating the upstream, ie the refinery for the fuels and the vapo. -reforming natural gas for the methanol case. The conclusion of this study is that overall, the rejection of a kilometric basis is very close to one sector to another, or more precisely, does not allow to identify a significant difference. level of the vehicle itself, the differentiation is sharper and the conventional fuel discharge is about 3.2 g / g of fuel consumed against 1 g / g of methanol. With the introduction of hydrogen in gasoline at about 5%, we would end up with a fuel economy of the order of 10% resulting in a reduction of the CO2 discharge in a larger proportion since the hydrogen does not introduce CO2. In addition, the impact at the refinery level is also interesting since the suppression of upstream reforming results in the loss of the associated reheating furnaces, the CO release of which can be evaluated at 0.2 g of CO2 per gram of reformai. Overall, we can expect a decrease in CO2 emissions of about 0.5 g / g of reformat consumed, which is quite significant.

Thus, if the C02 rejection gain is large at the vehicle level, it is practically nil if we take into account the entire methanol industry, in contrast in the reforming system embarked according to the present invention, the gain exists. for the vehicle alone and is even more important when you consider the whole. This can be illustrated by the following comparative examples of C02 release values for the most typical sectors 1) Refinery / petrol / internal combustion engine line 193.3 g / km 2) Natural gas / steam reforming / methanol / H2 stack 214.7 g / km 3) Embedded reforming die (present invention) 149.5 g / km It should be noted that the calculation of the C02 rejection value in the embedded reforming process, takes into account an improvement in the efficiency of 10 % on the fuel consumption and therefore, in the same proportions, on the C02 rejection of the vehicle. also took into account the impact on the refinery by the suppression of reforming furnaces whose CO 2 discharge can be estimated at 0.2 g / g of reformat produced.

Figure 2 illustrates the semi-regenerative variant according to the invention. Before the preheating 3 (exit temperature about 400 C) is the reforming reactor 15. This configuration is similar to semi-regenerative reforming refinery units whose catalyst is regenerated every year. In this version, the on-board reactor is dimensioned for a catalyst change at a frequency compatible with vehicle maintenance uses. Line 6 of exhaust gas is used to heat the reactor and / or control the temperature of the reaction. A cooler 16 the effluent at the outlet of the reactor allows the proper operation of the separator 8 downstream. An additional line 17 of hydrogen loop on the charge inlet line 2 to maintain a sufficient hydrogen partial pressure to limit the coking reaction associated with the present reforming reaction. An overpressure 18 provides sufficient pressure to return to the reactor. Without this step, it is virtually impossible, with currently known catalysts, to design a catalyst operating time compatible with embedded use.

Figure 3 illustrates the regenerative variant where the reforming reactor catalyst is regenerated continuously in a suitable device. In a simplified manner, the device 19 comprises the reaction means (sector and the catalyst regeneration means (sectors 21, 22, 23) .The principle uses a rotary barrel about the axis 24. The rotating part contains the catalyst disposed in tubes placed parallel to each other, along the axis 24. A fixed part, not shown for the sake of clarity, consists of an outer casing to the barrel, closed at both ends by covers including the elements of distribution of various fluids required for the catalytic reaction and the regeneration phases, which may be mentioned: injection of the vaporized charge (reference 25) into the reaction zone 20, outlet of the effluent (reference 26), inlet and outlet of the exhaust gas from engine 4 (respectively references 27 and 28) for heat exchange in the entire cylinder, - air injection (reference 29) dried The line 31 designates the supply of the exhaust gases for heat exchange, - entry by the line 32 of a portion of purified hydrogen by the purification means 33, the other part being recycled in upstream preheating 3, - inlet of the exhaust gas 34 discharged into the catalytic converter 35 (or equivalent), - reference 37 denotes the evacuation of the gases resulting from the regeneration, - reference 36 designates the mechanical means for driving in rotation the barrel.

In this embodiment, the rotating barrel may be composed of 100 19 mm diameter tubes filled with catalyst, 50 in reaction, 50 in the various regeneration phases. These tubes exchange heat with the engine exhaust gas. About 5 kg of catalyst would be needed in total (catalyst in reaction + catalyst in regeneration). The barrel can be about 20 in diameter, about 30 cm long.

Figure 4 schematically shows barrel according to the invention. The inlets 27a and 27b are respectively dedicated for the exhaust gases which will serve to provide heat of the reaction side to maintain a sufficiently high temperature, and regeneration side to eliminate excess heat. The incoming exhaust gas is at a temperature as high as possible, preferably around 500-600 C, and the exhaust gas entering 27b has been previously cooled to 400-500 C. The rotation of the cylinder is in 16h in operation, the catalyst in reaction being permanently, on average, in the same state of activity. It is necessary to bring the hot gas to different places distributed along the tubes with baffles in the barrel to separate four zones a, b, c, d. The endothermicity of the reaction is indeed very important (more than 400 C). To keep everywhere a sufficient temperature for the reactions to progress (this temperature does not need to be constant), one carries out the heat exchange at the four levels a, b, c, d in the barrel.

The catalyst fouls by coke deposition. He must be regenerated to find his activity. This regeneration consists essentially of burning coke. However, the catalyst rechlorination phase to disperse the platinum, followed by catalyst drying are necessary steps for a conventional catalyst. It is also necessary for the present catalysts to reduce the catalyst with reasonably purified hydrogen before contacting it with the feedstock. The examples were treated by considering, for example, the CR201 catalyst marketed by the company Procatalyse (France).

Figure 5 shows the different steps required and their sequential arrangement in the barrel. Sector I corresponds to the reaction part, sectors IV to purge phases, sectors II and III to two combustions, sector V to oxychlorination, sector VI to calcination and sector VII to reduction.

The regeneration starts with a purge (IV) to remove the hydrocarbons present in the catalyst - Entry <B>: </ B> Lean exhaust gas in 02. - Output: to engine exhaust. Combustion (II) - Entry: Exhaust gas and air, at about 350-550 C. - Exit: towards exhaust.

Combustion (III) - Entry: Exhaust gas and air, at about 400-600 C. - Exit to exhaust.

Burning can not be done in the air because of the excessive exothermicity which could destroy the catalyst (avoid carrying the catalyst to a temperature too high). The diluent gas used refinery typically a nitrogen / CO 2 mixture. In this case, the exhaust gas can be used once its CO has been removed by passing through the catalytic converter. The amount of air required for burning will be injected with this diluent gas. In the refinery, the O 2 content is strongly limited for the initial burning, so as to limit the increase in temperature. In our case, as an exchange with the exhaust gas that will limit the temperature differences, we can increase the oxygen content therefore limit the burning time whose duration is the greater part of the total duration of regeneration.

 Oxychlorination (V) - Entry: air at high temperature (400-600 C) and chlorinating product.

- Exit to exhaust. Calcination (VI) - Entry: dry air at high temperature (400-600 C). - Exit to exhaust.

 Oxychlorination and calcination (drying of the catalyst) will be carried out in the air. The air must be dried beforehand, which can be done with a small quantity of sieve (less than one kilogram) (Figure 3, reference 30). , which will be regenerated by heating with the exhaust gas (31) and then cooled by a portion of the dried gas. An air dryer (Figure 6) can be achieved by including a rotary system 40 with 16 sectors, which turns a sector every 10h of walking. Permanently, one can have sectors (S) in drying, in regeneration (R), 1 in cooling (F). size, the order of magnitude is: 10 cm in diameter over 10 to 15 cm length (this is less than a kilogram sieve). The reference designates the entry of ambient air for drying. The reference 42 designates the dry air outlet, sent to the main use: the reforming catalyst regeneration, and to the inlet of the sector F via the line 43 for cooling the screen, the air leaving the sector F by line 44 is returned to the atmosphere. Exhaust gases enter via line 45 into the sector R for regeneration of the sieve, the outgoing gases being sent to the exhaust line 46.

 Oxychlorination consists of dispersing precious metals on a catalyst. This operation is carried out at high temperature (for example between 400 and 600 ° C) in the presence of oxygen (air is perfectly suitable) and chlorinating product in very small quantities. A chlorination product injection line, not shown in Figure 3 is provided, for example on the air injection line (29) for the oxychlorination step.

Reduction (VII): - Entry <B>: </ B> purified hydrogen - Output: to motor The reduction phase requires purification of the hydrogen (33) output of the separator (8) to reinject it into reduction (32) . Once hydrogen is purified, it is also possible to draw a sufficient amount, using a small compressor, to create a recycling at the input reaction to limit the formation of coke. The purification system can be based on the use of two types of sieves in series in the same container, one for trapping aromatics, the other in lesser quantity to stop other hydrocarbons. Thus, sieving regeneration by heating is possible. The idea is to use hot hydrogen (400-500 C) at the outlet of the reduction to regenerate sieves and recover hydrocarbons to drive them to the engine. total amount of sieve would be around 20 kg, a barrel 35 cm diameter and 35 cm long, and it would turn the whole in about 3 hours.

Figure 7 illustrates the principle of a hydrogen purifier: a barrel with three sectors: adsorption (A), desorption (D) and cooling (H). Line 50 denotes the entry of hydrogen from separator 8, cooled to a temperature, preferably less than 50 ° C. Purified hydrogen is sent to the exit line 52. Hot hydrogen ( at more than 400 ° C) from the reduction outlet through line 53 for screen desorption. Part of the purified hydrogen is used (line for cooling the sieves after regeneration) The effluents at the outlet (D) and are sent via line 55 to the engine.

Simulation programs have made it possible to evaluate the yields of hydrogen and octane number of the fuel as a function of the flow rate of the charge. Indeed, in the acceleration phase of the engine, the load flow must be increased (decrease of the PPH mass flow load by weight of catalyst). It is necessary to check that in full acceleration one can obtain a sufficient octane number. It has been verified that for a charge flow rate varying in the proportion of 1 to 5, the octane number remains at a satisfactory level, likewise the flow rate of hydrogen. For such a charge flow, the octane number (RON) remains between 103 and 98. For the same variation in charge flow, hydrogen yield varies between 4 and 4.8%. In summary, the higher the flow rate, the lower the octane and hydrogen, but in acceptable proportions, the intermediate storage to dampen the fuel composition variations to the engine.

Claims (10)

1) Device for producing a fuel for a motorization, comprising at least one gasoline having a determined octane number, characterized in that it comprises - means for supplying a charge constituted by a gasoline direct distillation, - means preheating (3) said charge, - catalytic means (15; 19) reforming said charge to increase its octane number to said determined value; - separating means (8) for the hydrogen associated with the reaction reforming, - storage means (14) of gasoline of high octane number and / or hydrogen. 2) Device according to claim 1, comprising distribution means (11) arranged downstream of the separation means for directing the hydrogen to a motor (4) or a storage (12). 3) Device according to one of the preceding claims, wherein said catalytic reforming means (15) comprise a fixed catalyst bed reactor and injection means (17) upstream of the reactor of a predetermined amount of the hydrogen produced by the reforming reaction. 4) Device according to claim 3, wherein said injection means comprises a compressor (18) adapted to provide a predetermined partial pressure of hydrogen in the reactor. 5) Device according to one of claims 1 or 2, wherein the catalytic reforming means comprise a rotary drum (19) comprising the catalyst. 6) Device according to claim 5, wherein said barrel comprises a set of reactor tubes arranged parallel to the axis of rotation (24) of the barrel, so that each of the tubes carries out a cycle comprising a reaction phase followed by a set of regeneration phases, function of the rotation of said barrel. 7) Device according to one of claims 5 or 6, wherein said catalytic reforming means comprise different fluid flow means through the reactor tubes, constituted by upper and lower lids said barrel and having fluid supply orifices in tubes for the different phases. 8) Device according to one of claims 5 to 7, wherein said reforming means comprise means for controlling (27, 28) the temperature of the reactor tubes by an envelope containing the barrel. 9) Device according to one of claims 5 to 8, comprising drying means (30) of the ambient air and means for injecting dry air into reactor tubes in the regeneration phase. 10) Device according to one of claims 5 to comprising purification means (33) of hydrogen produces the reforming reaction. Device according to one of claims 9 and wherein the air drying means and the hydrogen purification means comprise molecular sieves. Apparatus according to claim 11, wherein said sieves are arranged in a rotating system to cycle at least three successive phases: adsorption, desorption, cooling. Device according to one of the preceding claims, wherein said engine is an internal combustion engine. Apparatus according to claim 13, wherein said engine is powered by said high octane gasoline and optionally by a quantity of hydrogen. 15) Device according to one of claims 13 or 14, wherein the exhaust gas of said engine is recycled to perform at least the heat exchange necessary for the catalytic reaction preheating. 16) Device according to one of claims 1 to wherein said motor comprises an electric motor powered energy produced by a hydrogen fuel cell, said hydrogen from the catalytic reforming. 17) Process for producing a gasoline having a predetermined octane number of hydrogen, characterized in that it uses the device according to one of claims 1 to 16. 18) Application of the device according to one of claims 1 at 16, to a system embedded on a vehicle. 19) Application according to claim 18, a vehicle comprising a combustion engine and an electric motor.