CS261748B1 - Process for reforming mixtures of heavy alcanoic and cyclanic petrols - Google Patents

Abstract

The reaction system comprises at least two types of platinorhene catalysts; one of which contains greater concentrations both metals in approximately equal amounts a the other contains less platinum and increased content rhenium and chlorine as activator. The carrier is pure alumina activated titanium dioxide. The procedure is characterized By taking the input temperature in a multi-stage system increases from the first stage by 2 to 8 ° C or and the same values gradually falling. Temperature at the first stage of the system it may be 20 to 80 ° C lower than 5 ° C second degree out of a total of four degrees. Catalyst combinations are particularly suitable for reforming higher content raw materials open.

Description

The invention relates to the reforming of mixtures of heavy alkanic and cyclanic naphtha at moderate hydrogen pressures on platinum-rhenium catalysts, at elevated temperatures high aromatic concentrates suitable for the production of unleaded autobenzines or for the production of pure aromatic hydrocarbons and mixtures thereof.

Catalytic reforming is the most important process of converting petrol into aromatic concentrates and technology, catalysts and equipment are constantly evolving. Demands for catalyst stability and activity, process economy associated with reduced energy consumption and increased yields of valuable products are increasing. The main technological direction in reforming is the semi-generational process, in which working periods alternate with periodic catalyst regeneration. The main type of catalyst is a platinum-rhenium catalyst in which the ratio of platinum to rhenium is approximately the same weight, the active metals being deposited on chlorine and titanium dioxide activated alumina, as described, for example, in AO 191 675 and AO 208 560. a range of processed raw materials, where one limit is formed by high alkanic types, the other by high-naphthenic types of hydrocarbon mixtures. The first is derived from alkanic petroleum, the second mainly from the processes by which the heavier hydrocarbon mixtures are converted to lighter, especially. from catalytic cracking and hydrocracking ·

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The invention describes a process for reforming mixtures of both types of heavy naphtha.

The process for reforming a mixture of heavy alkanic and cyclanic gasolines at hydrogen pressures in the range of 1 to 4 MPa on platinum-rhenium catalysts at temperatures in the range of 400 to 550 [deg.] C. is based on the invention to 5 introduce into a three to four-stage system comprising at least two different types of platinum-rhenium catalysts differing in the Pt: Re ratio, wherein in the first part of the system, consisting of one to two stages /, is catalyst A containing 0.20 to 0.40 % wt. of each of the metals Pt and Re on (c1) / 0rW alumina activated 0.6 to 1.1 wt% 0.05 to 0.5 wt% titanium dioxide, and in the remainder of the system is a catalyst By containing 0.20 to 0, 35 wt. and 1.5 to 3 times the rhenium to the actual platinum content of Catalyst B and 1.1 to 3.0

1.5 times the chlorine to the actual chlorine content of Catalyst A, the system stage volume ratio being 0 to 3: 1: 1 to 2: 1 to 4 and the inlet temperatures to the reaction stages being the same or increasing by 2 to 8 ° C or lower by 2 to 8 ° C, or in the first stage of the four-stage system the temperature is 20 to 80 ° C lower than in the second stage. Alkanické. the naphtha originates from the distillation of petroleum and the cyclanic naphtha are the products of the hydrotreating of the high-boiling petroleum fractions and contain 40 to 80% offsets. Cyclohexanes of all cyclanes and petrol have a boiling point between at least 70 and not more than 205 ° C.

In contrast to the prior art gasoline reforming processes, the process according to the invention extends the reforming with these catalysts to reforming to a combination of two types of catalysts and for higher-grade feedstocks, especially at higher pressures. The invention is well suited for improved utilization of older naphthenic feedstock units and can provide improved product stability and yields and even higher octane reformate numbers, especially when the sulfur content of the feedstock exceeds 0.1 to 0.2 ppm, troops reformed is the rule.

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The following example illustrates the process of the present invention and the results obtained using the process. However, the conditions set forth in the example are not intended to limit the scope of the invention.

Example

A 1: 1 mixture was prepared from an alkane naphtha and a hydrocracking naphtha containing 60% cyclohexenes of naphthenes present, the characteristics of which are shown in Table 1. 1. Two platinum-rhenium catalysts A and B differing in the ratio of platinum to rhenium were prepared for its reforming. Both catalysts were prepared on gamma alumina with a specific surface area of ISO m / g, activated with chlorine and titanium dioxide. The concentrations of the active components of the two catalysts are shown in Tab. 2.

A pressure apparatus with a catalytic volume of 120 ml was used to evaluate the progress of the reforming.

In the reforming experiments, they were compared at constant activity and stability parameters of the two catalysts alone and in combination with the invention. Activity was judged to be the temperature at which, under defined conditions, the octane number of the product 98 (lead-free) was reached. Stability was judged as the number of hours at which said OCM product was obtained in temperature ranges from activity temperature to 54 ° C. Three layers of catalyst were charged to the reactor and the catalyst was varied in layers. The modeling of the four layers was carried out by transferring the mixed feedstock at 440 ° C through one catalyst layer and passing the isolated product over a standard 3 layers in which 10, 20 and 40 ml of catalyst were successively.

The results of activity and stability measurements are shown in Tab. 3. Separate the paraffinic component of the mixed raw material a

261 748 the mixed feed alone and the mixed feed pre-reacted at 44 ° C. The catalyst layers were changed by using either a three-layer catalyst A or B (case δ. 1 and 2) and then a mixture of both so that the first two layers were catalyst A and the third one was catalyst B (case 3). 10 ml of catalyst A was used to prepare the pre-reacted feedstock. The results showed that the mixed feedstock (a) can be reformed on each of the catalysts at a lower temperature of 15 ° C than the alkane gasoline and the mixed pre-reacted feedstock (b) to 12 ° C. It can be seen that the mixture of catalysts A and B according to the invention has better activity than catalyst A and is virtually equal to catalyst B. The stability of the mixed catalyst system is greater than that of catalyst A and almost the same as catalyst B.

Table 1

Raw material for reforming - characteristics

20 May who. rain. Noc: 2 ° C 90 10% vol to 110 50 - · '- 132 90 168 end 190 hydrocarbon composition% Vol. paraffins 47 naphthenes 43 aromatics 10 sulfur ppm 0

Table 2

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Platinum-rhenium catalysts for reforming

(displacement diameter 1,7 mm) catalyst AND (B) Pt wt. 0.29 0.27 Re 0.29 0.55 Ti0 ₂ 0.10 0.10 Cl 0.70 1.20

Table 3

Catalyst activity and stability when testing various raw materials.

case δ raw material activity ° C 495 484 hours stability 420 600

485 475> 600> 600

490 482 .550> 600 ⁺ pressure = 1.5 MPa; LHSV = 5.0 h ^-1 , H ₂ :

CH = 5 molar

261,748 liters < tb &gt; &lt; tb &gt; &lt; tb &gt; ______________________________________ &lt; tb &gt; ______________________________________ A and in the second case catalyst A was added to the first layer and two catalyst B were added to the other two. In the second alternative, the temperatures increased by 5 ° C from the first to the third layer. Other conditions were chosen the same - p = i, 5 MPa,

LHSV = 2, Oh. The stability of the catalysts was monitored as a function of the temperature required to reach the OMV reformate 98 over time. For 1, the alternative achieved catalyst combinations increased stability by 21%; for the second alternative of elevated temperatures, activity was even increased by 32.5%.

In another series of experiments, catalyst B was deposited in all reactors as compared to the catalyst mixture A and B of the invention. In the mixed feedstock, the sulfur content increased from 0.1 ppm to 1 ppm by addition of carbon disulfide. The stability of the catalysts of the invention has not changed and the stability of Catalyst B in all layers has decreased to 75% of the value of Catalyst A.

Claims (2)

SUBJECT OF THE INVENTION 261 748 What is claimed is: 1. A process for reforming a mixture of heavy alkane and cyclanic naphtha at hydrogen pressures in the range of 1 to 4 MPa on platinum-rhenium catalysts at temperatures between 400 and 550 [deg.] Cc. to a three to four-stage system comprising at least two different types of platinum-rhenium catalysts differing in the Pt: Re ratio, wherein in the first part of the system consisting of one to two stages / catalyst A comprises 0.20-0.40 wt. of each of the metals Pt and Re on alumina activated 0.6 to 1.1 wt. % chlorine and 0.05 to 0.5 wt. % of titanium dioxide, and in the remainder of the system, catalyst 8 contains 0.20-0.35 wt. platinum and 1.5 to 3 times rhenium for the actual platinum content in Catalyst B and 1.1 to 1.5 times chlorine for the actual chlorine content in Catalyst A, wherein the system volume ratio is 0 to 3: 1: 1 to 2: 1 to 4 and the inlet temperatures to the reaction stages are the same or increase by 2 to 8 ° C or decrease by 2 to 8 ° C from the first stage to the fourth, or the temperature in the first stage of the four-stage system is 20 to 80 ° C lower than in the second stage. 2. A process according to claim 1, wherein the alkane naphtha originates from the distillation of petroleum and the cyclanic naphtha is from the hydrotreating of high boiling petroleum fractions and contains 40 to 80% by volume of cyclohexanes of all cyclanes and boils at least 70 and at most 205 ° C,