DD223146A1 - METHOD FOR FLAVORING FLAVORING HYDROCARBONS - Google Patents

Abstract

The invention relates to a process for the aromatization of low-boiling hydrocarbon mixtures having improved selectivity at pressures between 0.7 and 2.0 MPa and elevated temperatures in the presence of hydrogen-containing gases over catalysts which, in addition to platinum and / or rhenium and chlorine on gamma-Al 2 O 3, at least one further component from the group iridium, chromium, copper, manganese, titanium and / or tin in amounts of from 0.01 to 1.0% by mass, and at least one second component from the group of alkali, zinc and / or iron in amounts of from 0.001 to 1 Mass% included. The catalysts used have at a pore volume of at least 0.50 cm3 / g, a proportionate pore volume for the radius range of 2.0 to 10 nm of 70 to 90% and such for radius ranges greater 50 nm from 2 to 20%, preferably in Radius range between 1.5 and 4 nm, a proportion of 35 to 65% of the total pore volume is present. The catalysts continuously pass through the Reaktionsraeume in a ratio of 510 4 to 5010 4 based on the amount of the processed hydrocarbon mixture and are then regenerated in batches.

Description

Title of the invention

Process for flavoring low-boiling coal hydrogen mixtures

C 07 c 5/22

Field of application of the invention

The invention relates to a process for aromatizing low-boiling hydrocarbon mixtures in the presence of hydrogen-containing gases . elevated pressure using a suitable catalyst, which is continuously regenerated in batches *

Characteristic of the known technical solutions

The aromatization of hydrocarbon fractions of the boiling range a 340-420K under typical forming conditions on platinum-, alumina-type catalysts for the preferential recovery of BTX aromatics is known (e.g., DD-PS 135,970). In particular, the conversion reactions of the Cg and Cy hydrocarbons leading to benzene and toluene place considerable demands on the performance of the catalysts used, since aromatization reactions take place satisfactorily only at relatively high temperatures and relatively low pressures. Under conventional reforming conditions in the pressure range of about 2 MPa, therefore, the aromatics yields are unsatisfactory. , . '

Reformierungsverfahrensvarianten have become known, which apply the principle of continuous regeneration of the catalyst (DE-OS 2 255 497) and thereby the for the expiration of aromatization reaction

For example, the bi-type and / or multimetal catalytic analyzers used are subject to high demands with regard to mechanical stability and regulation.

generation stability. Lifting various catalyst compositions (eg DE-OS 2 460 560, DE-OS 2,541,186, US-PS 4,239,652) are specific regeneration methods (eg DS-OS 2 255 497) as well as special treatment instructions (eg DD-PS 137 940) to meet the technically demanding process. Despite these undoubtedly advantageous solution variants, it is still not possible to avoid adverse effects due to unselective cleavage reactions of the catalysts. These disadvantages caused by special catalyst properties are often more pronounced when using fresh or freshly regenerated catalysts and are therefore particularly noticeable in the case of aromatization processes which work with continuous regeneration of the catalyst, since in this case reactivation. steps must be carried out at timely intervals. In many bimetallic catalysts, in particular of the system Pt-Ir-Al ₂ O ', there is also the tendency to observe, that in combination with the formation of aromatics, in particular at elevated temperatures,: dealkylation reactions.

, run, whereby the C number distribution of aromatic hydrocarbons is often undesirable loading, is influenced. '

Bs are also known processes in which aromatic hydrocarbons by means of special catalysts from n-paraffins or n-paraffin-rich fractions, in particular the Cg * range are obtained. (DD-WP 142 271)

However, the provision of the required raw materials for such processes is associated with increased expenses, so that these, process variants have not been widely used. Similar catalysts characterized by relatively high levels of chromium oxide are also described in U.S. Patent 3,554,901 for aromatization. :. ·.

Object of the invention

The object of the invention is to propose a process for flavoring low-boiling hydrocarbon mixtures with improved selectivity, taking into account the particularities of continuous regeneration of the catalyst used.

Explanation of the essence of the invention . -

It was therefore the object to carry out the aromatization of low-boiling hydrocarbon mixtures on a catalyst which ensures a high selectivity of the hydrocarbon conversion under the specific conditions of a continuous catalyst regeneration.

This object is achieved by a process for aromatization of low-boiling hydrocarbon mixtures at pressures from 0.7 to 2.0 MPa and at elevated temperatures in the presence of hydrogen-containing gases • of catalysts containing at least 0.1 to 1% by mass of platinum and / or 0.1 to Containing 1.0% by mass of rhenium and 0.1 to 3% by mass of chlorine and further components acting as a promoter, which catalysts are used according to the invention which consist essentially of spherical gamma-aluminum particles

consist of a pore volume of at least 0.50 cm / g and a pore volume fraction for pores with 2.0 to 10 cm radius of 70 to 90 % of the total pore volume. The pore volume fraction for pores with radii greater than 50 nm is in the range between 2 and 20 % of the total pore volume. The catalysts comprise at least one further component from the group consisting of iridium, chromium, copper, manganese, titanium and / or tin in amounts of from 0.01 to 1.0 Hasse%, preferably from 0.01 to 0.5 mass -%. It is furthermore essential that the catalysts contain at least one further second component from the group consisting of alkali, zinc and / or iron in an amount of between 0.001 and 1.0.% By weight, where the content Alkalioside preferably at 0.002 to 0.05% by mass and the contents of zinc or .. Sisen at 0.01 to 0.5% by mass. As the alkali component, sodium compounds have proven '. In accordance with the process of the invention, the catalysts continuously pass through the reaction spaces in which the hydrocarbons are reacted, with a catalyst being used, based on the amount of hydrocarbon mixture processed.

'' '-A - 4 · -

Lysatormenge from 5.TO to 50.10 is withdrawn from the reaction chambers. After passing the last reaction space, the catalysts are regenerated in batches and reactivated and re-introduced into; the ratio quoted with the hydrocarbon feed and hydrogen continuously supplied to the reaction spaces. /

It is also essential for the process according to the invention that the catalysts used have a proportionate pore volume for pores with radii between 1.5 and 4 nm of 35 to 65% of the total pore volume. In a particularly advantageous embodiment, the catalysts used have a

Pore volume fraction for pores with radii between 1.5 and 3 nm of 15 to 40 % of the total pore volume and such for pores with radii large 50 μm of 3 to 10 % of the total pore volume.

In a further expedient embodiment, catalysts are used which are prepared by a continuous and two-stage reaction of aluminum salt solutions with Hatriumaluminatlaugen at temperatures between 323 and 363 E, at pH Y / erten between 7.0 and 8.5 »at concentrations between 40 and 70 g in the reaction mixture and at residence times between 5 and 240 minutes in the reaction steps to boilimite hydrogel, processing into spherical particles with a diameter of 1.5 to 3 mm, conversion to gaimna alumina by thermal treatment and applying the corresponding active component combination are prepared.

The special component combinations platinum-rhenium-chromium-iron, platinum-rhenium-chromium-sink, platinum-rhenium-iridium-sis and platinum-rhenium-manganese-zinc have continued to live in the special pore distribution that has proven particularly effective. proved to be particularly useful. , :

Surprisingly, low-boiling hydrocarbon mixtures with high selectivity can be converted into aromatics-rich primes by the process according to the invention. In addition, the catalysts used in the process are characterized by excellent regeneration properties and influence processes with continuous batchwise, catalyst regeneration in a very positive manner.

Exemplary embodiments ·

In a catalytic test apparatus, the following catalysts were compared in the reaction of a hydroraffinated benzine fraction of the boiling range 70-139 ⁰ G:

•. ':.' Catalyst.A Catalyst B 'Catalyst''. *:. ", tor C

   : '' (.Composition'in% by mass)

platinum 0.6 0.6 0.6 rhenium 0.35 0.35 0.35. ' ("or 0.05K) Cr ₂ O ₃ 0.15 0.05. - zinc 0.05 -. ' iron 0.06 ; <O, oi <0.01 Ha ₂ O : 0.03 0.03 <Ö, O1

Catalysts A and / B represent catalysts for the process according to the invention; Catalyst C is a typical catalyst for prior art processes. -. '., ...

All catalysts were used as spherical particles about 2 mm in diameter. ,. The catalysts are further characterized by the following pore distribution:. ,

Catalyst A or Cat. B Cat. C

Pore volume cirr / g 0.58 0.54

Share for r_ 2 -10nm 83 % '. 96 %

Proportion for r_ '1.5-4 nm' 53 % 32 %

Proportion for r_ 1.5-3 nm 32 %. , 12 % . ,

Share for ^! r _p 5.0 nm 7 %. ''. <2%

Beiapiel 1 -

These catalysts ..- were in a small-scale pilot plant with the hydroraffinated en gasoline cut the Siedelage 70 - 130 ⁰ C passed under the following parameters:

Pressure 1.2 MPa

Hp / hydrocarbon ratio: 6: .1 (mc catalyst loading: · 1.9 v / vh

'^ .., temperature:. 480 - 550 ⁰ G

ν

The temperature was / was carried out during the experiment so that an aromatics yield based on the feedstock of 50 Ma. -% was achieved.

, Cat. A Cat. B Cat, C

Catalyst runtime until reaching the Snd 595, 610 510 temperature of 550 ⁰ C (h)

Carbon content

(gC / gKatxh) 1, O5.1O " ⁴ 1,12.10" ⁴ 1,2O.1O "" ⁴

C _f - ⁺ -5 ¹ liquid. , , '

booty (through-

'. average value) 77.4 76.9; 76.2.

    '(% By mass);

Hp yield,

(Average 2.95 '2.9 V 2.86

value) (% by mass) '.

The advantages of the catalysts used according to the invention lie in a high selectivity with respect to aromatics formation and in a high hydrogen peroxide yield and good catalyst stability.

Example 2 \, '·.

The catalysts B and C according to Example i differ in their long-term behavior, which is due to the different carbon formation. This resulted in different regeneration rates relative to use in the moving bed reformer.

Reeeneration «rate · supplied mass. Selective.Cat. * Reverse Axes Rule. _supplied ; _e mass of feedstock / h

x) bz-s. sensed mass of G-loaded catalyst "":

The regeneration rate is for moving bed reforming processes, since these processes are always designed for a: 'limited' C-end value, a characteristic parameter for comparing the performance of catalysts. : ''. '

Cat. B _{; ;} 'Cat. C

    '-λ. - *}

Regeneration rate 2.25. 10 ^J 3.10. TO ν.

This means that at the same carbon en dvi er the catalysts, the catalyst 3 needs to be supplied to the process in small mass per unit time, · or be operated with high Severity 'can ^ This results in a higher yield of target products.

Claims (3)

Invention claim. 1. A process for aromatizing low-boiling hydrocarbon mixtures at pressures between 0.7 and 2.0 MPa and elevated temperatures in the presence of hydrogen-containing gases over catalysts containing at least 0.1 to 1.0 mass% of platinum and / or 0.1 up to 1.0% by mass of rhenium and 0.1 to 3% by mass of chlorine and other promoters Contain components, _: Characterized in that catalysts are used, which consist essentially of spherical gamma-Al _o 0, particles consist of at least 0.50 with Porenvoluaina cr / g, a proportionate share; lone pore volume of 70 to 90 % for pores ; Radii between 2.0 and .10 nm and such , from 2 to 20 % for pores with radii greater than 50 nm and at least one further component from the group iridium, chromium, copper, manganese, titanium and / or. Sense in amounts between 0.01 and 1.0. Mass% and at least one more second com component from the group consisting of alkali, zinc and / or iron in quantities between 0.001 and 1.0 mass%, these catalysts continuously in a Ver. -4. _4 ratio of 5.10 to 50.10 in relation to the Amount of processed hydrocarbon mixture pass through the reaction chambers and then regenerated and reactivated in batches - 10 - and again with the hydrocarbon feed and hydrogen continuously supplied to the reaction spaces in the above ratio. 2. The method according to item 1, characterized in that .the catalysts used a proportionate pore volume for pores having radii between 1.5 and 4 .mu.m of. 35 to 65% of the total pore volume and at least one further component from the group iridium, chromium, copper, manganese, titanium and / or tin in amounts of 0.01 to 0.5 mass% and at least one further ^: second component the group alkali, zinc and / or iron in amounts of 0.002 to 0.05% by weight of alkali metal and 0.01 to 0.5% by mass: for zinc or iron. 3. 'method according to item 1 and 2, characterized. in that the catalysts used have a proportional pore volume for pores with radii of between 1.5 and 3 nm of 15 to 40 % of the total pore volume and such for pores with radii greater than 50 nm of 3 to 10 % of the total pore volume respectively. , '/