GB2124369A

GB2124369A - Catalytic test apparatus

Info

Publication number: GB2124369A
Application number: GB08318196A
Authority: GB
Inventors: Hubert Ajot; Rochettes Bertrand Mercier Des; Christian Marcilly; Jacques Bousquet
Original assignee: IFP Energies Nouvelles IFPEN; Elf France SA
Current assignee: Elf Antar France; IFP Energies Nouvelles IFPEN
Priority date: 1982-07-05
Filing date: 1983-07-05
Publication date: 1984-02-15
Also published as: DE3324044A1; FR2529472B1; FR2529472A1; GB8318196D0; GB2124369B

Abstract

Catalytic test apparatus is provided for use in refining, petrochemistry, treatment of synthesis gas or fine chemistry. The apparatus includes a fixed bed catalyst tubular reactor (2, 10, 11, 12), means (1, 6, 7) for injecting a charge of material into the reactor, a furnace (3) heatable to a temperature in the range of from 50 to 300 DEG C, a plurality of sampling valves (14) located in series or in parallel in the furnace (3) at the output of the reactor for receiving and trapping effluent from the reactor, means (15, 16) for measuring a gas feed rate, and analysis means (5, 17, 18) operable to receive each of the valves for analysis of their trapped contents. <IMAGE>

Description

SPECIFICATION Catalytic test apparatus This invention relates to a catalytic test apparatus and concerns such an apparatus particularly, but not exclusively, suitable for use in refining, petrochemistry, synthesis gas treatment and fine chemistry.

Conventional fixed bed microcatatest type apparatus are known in which a the charge is generally injected by means of a pump and passes in admixture with a carrier gas over a fixed bed catalyst placed in a tubular rector. At the outlet of the rector the effluents are recovered in a cold trap, when in the liquid form, or in a gas bulb, when in the gas form and an overall weight balance of the operation is obtained by determining the total amount of the liquid products and the total volume of the gas effluents recovered followed with a chromatographic analysis of each of the two phases. However this method, which is conventional as concerns the apparatus, necessitates the separate analysis of two phases, a liquid phase and a gas phase, and allows only one determination of the activity per balance.

Another known test apparatus utilises direct-in-line analysis of the effluents by chromatography at the reactor outlet. This system has the advantage of determining the activity of the catalyst in the very first moments of its operation but chromatographic analysis over a long period forbids the determination of several points at short time intervals of the measuring.

There is thus a need for a generaily improved catalytic test apparatus.

According to the present invention there is provided a catalytic test apparatus operable under atmospheric pressure or superatmospheric pressure, including a fixed bed catalyst tubular reactor, means for injecting a charge of material to be tested into the reactor, a furnace heatable to a temperature in the range of from 50 to 3000C, a plurality of sampling valves located in series or in parallel in the furnace at the output of the reactor for receiving and trapping effluent from the reactor, means for measuring a gas feed rate, and analysis means operable to receive each of the valves for analysis of their trapped contents.

The apparatus of the invention can provide instantaneous analyses performed in a very short time, thanks to the successive samplings of the hot effluent by means of the system of chromatographic valves placed serially or parallely at the outlet of the reactor. Conventional apparatuses require a far longer injection time to accumulate a sufficient amount of products for a correct analysis.

The apparatus of the invention, by hot sampling, avoids the separation of a liquid phase and a gas phase and their distinct analysis, and allows several samplings to be made within a very short time and the hot storage thereof before further analysis. This hot storage avoids the condensation of the heavy products on the valve means. This is particularly advantageous for observing a quick deactivation or the initial period of use of a catalyst.

For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying single figure drawing which shows in diagrammatic form a catalytic test apparatus according to one embodiment of the invention.

The apparatus of the invention comprises a feed zone 1, a reaction zone 2 having means for controlling a gas feed rate 1 5, and a zone 3 for collecting samples in a plurality of valves 14 with an analysis means 5 for each sampling valve 14 whereby each valve 14 can be received and the contents thereof analysed.

The number (n) of valves 14 may range from two to eight, preferably from three to six. The apparatus provides a conventional microcatatest system (zone for feeding the reactants and controlling the gas feed rate) combined with means for sampling and analyzing the effluents by means of sampling valves. This arrangement makes it possible to effect, in one single operation, several determinations of activity, selectivity and thus stability of the catalyst with respect to time.

A feed charge 7 is injected from a syringe pump 6 and passed through a line 8, together with a carrier gas fed from duct 9, into a fixed bed catalyst tubular reactor through a preheating zone 11 and then through the catalyst bed. The preheating and the reaction mixture are maintained at a constant temperature in a controlled furnace part. The device for sampling the effluents, placed at the outlet of the reactor, comprises a thermally controlled furnace heatable to a temperature in the range of from 50 to 3000 C, containing valves 14 stacked in series or in parallel. These valves are successively closed as effluent passes therein from the reactor, thus isolating a certain amount of effluent in a container of known volume.The means for closing the valves, operated with a key 1 3 consists of displacing a conical piston which pushes the container in the direction of a second stationary cone. This means has been disclosed in the French Patent No. 6 910 998 filed on April 10, 1969 by ELF-ERAP. The untrapped gas stream continues to circulate around the periphery of the closed valve container and the feed rate of the gas 1 6 can be determined with a mercury-sealed volumeter 1 5. Once the effluents have been trapped in the closed valve containers, the content of each trap or valve container is analyzed by analysis means 5 preferably using chromatography. The transfer of each valve container to the analysis means 5 is shown by the symbolic arrow 4.The transferred valve container 1 8 is heated in a furnace 1 7 placed in the analysis circuit. A six-way valve can be used to remove the air present on the periphery of the container by scavenging with a carrier gas to the exterior and to connect the trap or container with the analysis system. The valve container is then opened, liberating the effluents for supplying the chromatography column. Each valve not yet used is stored in the heat regulated sampling furnace 3.

It must be noted that this system has the advantage of being easily adaptable to other analysis devices (mass infra-red or ultra-violet spectrometry).

The catalytic test apparatus of the present invention has a great number of uses either under pressure or superatmospheric pressure particularly in refining, such as for catalytic cracking, hydrocracking reforming, hydroisomerization or hydrogenation, in petrochemistry, such as for aromatic conversion (isomerization, dismutation, hydrodealkylation) or various oxidations (oxidation of toluene to - benzaldehyde, of methanol to formaldehyde), and in CO+H2 chemistry (treatment of synthesis gas) such as for methanol synthesis, conversion of methanol to hydrocarbons, or conversion of CO+H2 to higher alcohols.

EXAMPLES: The following examples illustrate the use of the apparatus of the invention and relate to fixed bed catalytic cracking of cyclohexene under atmospheric pressure, the catalyst being of the zeolitic type.

EXAMPLE 1 Three experiments of cyclohexene cracking were performed under identical conditions in the fixed bed reactor of the apparatus of the invention under atmospheric pressure and at a temperature of 5000 C. The reactor was charged with 1 g of the zeolitic catalyst. From time zero, cyclohexene was injected at a constant rate through the syringe pump and supplied with a carrier gas to the catalyst bed where it was converted. The cracking effluent was then supplied to the four sampling valves 14 stocked in the furnace 3 heated to 2000C.

The valves were closed one every two minutes and at the end of the catalytic test, the closed valves were successively transferred to the chromatographic apparatus where their contents were analyzed.

The valves not yet used remained in the hot furnace. Table 1 gives the results obtained in three identical tests with four samplings performed each two minutes. The reproducibility was lower than 1%.

EXAMPLE 2 The conditions being the same as in Example 1, cyclohexene was cracked in an apparatus of the invention provided with four sampling valves. Two samplings were each effected by closing two valves simultaneously.

One of the two closed valves of a sampling was analyzed immediately, while the other one was maintained hot for fifteen days and then analyzed.

Table 2 shows that the reproducibility remained at 1%, irrespective of the long residence time in the hot sampling furnace.

EXAMPLE 3 The test of Example 2 was repeated, except that the storage for 1 5 days of one of the two closed sampling valves was performed in the cold. The results of Table 3 show that the reproducibility is not so good, which shows the importance of a hot storage of the sampling valves.

TABLE 1

# = 500 C/ATMOSPHERIC PRESSURE/V.V.H. = 0.5 s-1 TEST (1) TEST (2) TEST (3) t1 t2 t3 t4 t1 t2 t3 t4 t1 t2 t3 t4 - Sampling time = = = = = = = = = = = = 2 mn 4 mn 6 mn 8 mn 2 mn 4 mn 6 mn 8 mn 2 mn 4 mn 6 mn 8 mn - Conversion % mol. 93.5 92.5 91.5 90.5 93.5 92.5 91.5 90.6 93.3 92.5 91.5 90.4 - Methylcyclopentenes % mol. 43.8 45 45.6 46.4 44 45 45.7 46.4 43.9 45.1 45.6 46.3 - Methylcyclopentane % mol. 17.8 16.4 15.6 14.8 17.7 16.5 15.6 14.8 17.7 16.3 15.3 14.7 3 2.95 3.03 2.98 2.97 2.96 3 3 3.02 2.98 3 3.04 - Total area of the chromatographic peaks x 105 x 105 x 105 x 105 x 105 x 105 x 105 x 105 x 105 x 105 x 105 x 105 TABLE 2

1st PAIR OF VALVES 2nd PAIR OF VALVES t1 = 2 mn t2 = 4 mn Valve analysed Valve stored hot Valve analysed Valve stored hot immediately (15 days) immediately (15 days) Conversion 93.4 93.4 92.6 92.5 Total area of the chromatographic peaks 301000 300000 296000 295000 TABLE 3

1st PAIR OF VALVES 2nd PAIR OF VALVES t1=2mn t2=4mn Valve analysed Valve cooled Valve analysed Valve cooled immediately (15 days) immediately (15 days) Conversion 93.3 70 92.7 60 Total area of the peaks 296000 1 220000 304000 180000

Claims

1. A catalytic test apparatus operable under atmospheric pressure or superatmospheric pressure, including a fixed bed catalyst tubular reactor, means for injecting a charge of material to be tested into the reactor, a furnace heatable to a temperature in the range of from 50 to 3000C, a plurality of sampling valves located in series or in parallel in the furnace at the output of the reactor for receiving and trapping effluent from the reactor, means for measuring a gas feed rate, and analysis means operable to receive each of the valves for analysis of their trapped contents.

2. An apparatus according to claim 1 wherein the analysis means is a gas phase chromatograph, a mass spectrometer or an infra-red or ultra-violet device.

3. A catalytic test apparatus substantially as hereinbefore described with reference to the accompanying drawing.