Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
  • G01N31/10—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using catalysis
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
  • G01N30/02—Column chromatography
  • G01N30/04—Preparation or injection of sample to be analysed
  • G01N30/06—Preparation
  • G01N30/12—Preparation by evaporation
  • G01N2030/125—Preparation by evaporation pyrolising
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
  • G01N30/02—Column chromatography
  • G01N30/62—Detectors specially adapted therefor
  • G01N2030/621—Detectors specially adapted therefor signal-to-noise ratio
  • G01N2030/625—Detectors specially adapted therefor signal-to-noise ratio by measuring reference material, e.g. carrier without sample
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
  • G01N30/02—Column chromatography
  • G01N30/04—Preparation or injection of sample to be analysed
  • G01N30/06—Preparation
  • G01N30/10—Preparation using a splitter

Definitions

• This invention relates to an arrangement, equipment and method for testing catalysts for short contact time reactions. It is a novel application of capillary technique where capillary tubing and separation columns are used as on-line sampling probes as well as for separation of compounds.
• the equipment is feasible for testing catalysts and catalytic reactions with short contact times, it is operated by pulse method and the products are analysed preferably using on-line gas chromatography.
• a Py-GC application is also presented in patent application WO 94/20848 which provides an improved sample injector for use in gas chromatography.
• the injector features an arrangement to allow a pyrolytic probe to be more easily inserted into the vaporization cavity while permitting the sample to be volatilized in such a way that the sample is more efficiently introduced onto the column.
• the invention is a novel application of capillary technique. Pulse mode of injection, hydrogen response and analysis of hydrogen, hydrocarbon compounds from Ct to C 2Q in products are detected simultaneously using flame ionisation (FID) and/or mass-selective and/or TCD and/ or AED as detectors, and capillary tubing and separation columns are utilized as on-line sampling probes as well as for separation of compounds.
• FID flame ionisation
• TCD and/ or AED mass-selective and/or TCD and/ or AED
• capillary tubing and separation columns are utilized as on-line sampling probes as well as for separation of compounds.
• the equipment for testing catalysts according to the invention is herein abreviated as ETC.
• the coke deposited on the catalyst is determined using well-known techniques by passing pulses of oxygen over catalyst and analysing amounts of products with on-line GC.
• the arrangement and equipment according to the invention are well suited in testing and monitoring of heterogeneous catalysts, catalytic reactions, cracking reactions, skeletal isomerization reactions, measurements of catalyst deactivation, dehydrogenation, methane coupling and hydrogenation with short contact times.
• the equipment is operated by pulse method and the products are analysed for example by on-line gas chromatograph.
• the equipment comprises preferably a furnace, a gas chromatograph furnished with suitable detectors, a tube reactor, gas and liquid injection valves, temperature measurement controllers, reactor and colum head pressure adjusting valve, mass-flow controllers and an injector.
• gas oil is injected into the upper section of the reactor by generally known means.
• the individual components and compounds can be separated conveniently using capillary columns.
• Any oils and gases with the boiling point equal or less than 550 °C can be used as feedstock.
• the reactor can be operated within the temperature range of 20— 900° C depending on the feed, reaction and reaction circumstances, with wide catalyst to oil ratios and with residence times 0.01—0.1 s without losing resolution of compound separation.
• compound level resolution can be achieved with residence times 0.01—0.3 s.
• compound level resolution is deteriorated and only GC-distillation results are obtained.
• the equipment is preferably constructed by using commercial components and/or components specially designed for the purpose.
• the major components are a furnace which gives a broad and uniform temperature profile, a tube reactor, preferably of glass, steel, other suitable metal, ceramic material or quarz, adapter units, gas and liquid injection valves, preferably six-way valves, a gas chromatograph furnished with a suitable detectors, such as flame ionisation (FID) and/or mass-selective and/or TCD and/or AED and preferably FID and TCD, mass-flow and temperature measurement controllers, reactor and column head pressure adjusting valves, and an injector, preferably a semi-automatic one.
• FID flame ionisation
• TCD mass-selective and/or TCD and/or AED
• FID and TCD mass-flow and temperature measurement controllers
• reactor and column head pressure adjusting valves preferably a semi-automatic one.
• the tube reactor 2 is connected into an injection port 36 of GC 20 with two special adapter units 29 and 16.
• first adapter unit 29 there are six input holes for reactor 2, separation column 38, split- gas capillary inlet 14, split-gas outlet 13, temperature measurement probe 30 and pulse measurement and hydrogen sample capillary probe 31.
• the separation column 38 is inserted through the injector septum 19 and liner tube 37 and lifted up into the reactor tube 2 30 mm below the catalyst bed 5 with a specially constructed second adapter 16. In this way separation column 38 can be used as a sample probe for online sampling as well as for separation of compounds.
• the reactor and injector are phase separated with gas-tight septum 17.
• the tip of thermocouple 7 is placed just below the catalyst layer 5.
• the both adapter units 29 and 16 are heated to constant temperature (200 °C) with a heating block 10.
• the feed 24 is injected into the reactor 2, preferably either manually or using semi-automatic injector or gas or liquid injection valves and the compounds in the product which is analyzed are separated with a capillary column 38 and detected with FID 39.
• a six-way valve or gas or liquid injection valves 22 and a sample loop can be used in the case of applying gaseous feed in tests.
• a TCD 26 is used as a pulse mode detector and another TCD 27 used for hydrogen detection, is placed in a coke measurement system. It is also used for detection of permanent gases and unreacted oxygen of the oxidizing pulse in catalyst regeneration.
• 1 represents manual injection block, 21 manual injection septum, 3 furnace, 4 and 6 quartz wool,
• a microscale reactor has a threefold mode of action. It operates simultaneously as a vaporiser or injector, a reactor and a sample splitter.
• the upper section of the reactor acts as a vaporising zone where liquid feed is evaporated.
• Carrier gas transports the vaporized feed into the middle zone of the reactor where it is in contact with the catalyst and reactions occur.
• the lower zone of reactor tube may be converted to a sampling area where the tip of sample probe for pulse measurement and hydrogen analysis is located just below the catalyst. Splitting of product gas between pulse measurement and compound analysis can be adjusted with mass-flow controller connected to the outlet of TCD.
• the product gas Downstream after sampling probe the product gas is diluted with extra helium gas flow with a split-gas capillary.
• a sample for compound analysis is taken from the diluted product flow using second sampling probe.
• the reaction zone is located at the most uniform area of the temperature profile of the furnace.
• the residence time of feed over catalyst is controlled with carrier gas flow rate and the split-ratio with split-gas flow rate.
• the pressure of the reactor and the effluent gas flow rate are adjusted with column head pressure regulator which is connected to split-gas outlet line.
• tube reactors have been utilized.
• a layer of quartzwool or other suitable material is placed in order to adjust the position of catalyst.
• the reactor is cleaned from contaminants by flushing it with oxygen pulses at the same temperature where the regeneration was carried out.
• Suitable amount of catalyst is 0.01—300 mg and it is loaded in the middle of the tube reactor, in the zone where the temperature profile of the furnace is most uniform.
• gas oil is injected into the upper section of the reactor manually or with a semi-automatic injector.
• gaseous feed gas loop is preferably used for injection. If the boiling range of the feed is low enough, for example 100—150 °C, liquid injection valve may also be used.
• a capillary column is used as a sample probe for on-line sampling as well as for separation of compounds.
• the tip of the separation column is placed approximately 15 mm below the tip of split-gas capillary.
• Split ratio and delay time in sampling zone are adjusted with split-gas flow. Due to small dead volume in the sampling area a temperature program with starting temperature 0 °C (2 min) and rate speed of 1.5 ° C/min to the final temperature of 300 °C is a preferable and proper method to achieve resolution of compounds from C j to C 2Q -
• the amount of coke can be measured for example with a pulse method using separate equipment. Calculation of the coke amount is based on external calibration carried out in the same way using coke samples as reference, the amount of coke of which is analyzed using commercially available methods.
• the lowest possible operating temperature of the reactor depends on the boiling range of the oil.
• the liquid feed is vaporised in the beginning of the catalyst/ inert bed which allows gas phase reactions.
• the volatilisation of the liquid feed is ensured by high mass-ratio between the catalyst/ inert bed and the feed, also the temperature drop in consequence of the volatilisation is very small. Gas phase feed to the reactor is also possible.
• the highest operating temperature is restricted to the temperature of 900 °C.
• the feedstock may be any kind of liquid or gas feed with the boilig point equal or below 550 °C.
• the viscosity of the liquid phase feedstock must be low enough to ensure uniform injection. In the case of high viscosity at room temperature the feed must be heated to a sufficient temperature.
• the amount of the feed can be varied in the range of 0.1— 1.0 ⁇ without loss of resolution or stability of temperature.
• the maximum lenght of the catalyst bed is restricted to 30 mm because of the temperature profile of the heating oven.
• the temperature profile in the region of the catalyst bed should be as flat as possible in order to ensure uniform temperature in the bed and therefore uniform conditions for the reactions.
• the catalyst to oil ratio can be varied within a wide range of 0—300.
• the catalyst to oil ratio may be in the range of 0—45 g ca ⁇ /goii with diameter of the reactor 2 mm.
• the length or volume of the catalyst/inert bed is always kept constant, only the mass fraction of the catalyst in the bed is varied.
• the residence time of the feed in the catalyst can be controlled indirectly by varying the flow rate of the carrier gas through the reactor.
• the flow rate of the carrier gas may be varied between 0.1—83.3 cm 3 /min (NTP), which corresponds to the residence times of 0.01—5.9 s , at 600 °C, bed volume 22.9 cm 3 of the carrier gas.
• NTP 0.1—83.3 cm 3 /min
• the first step in the test method is to load a known amount of catalyst into the tube reactor. After loading the reactor is connected to the adapter unit of test equipment and the furnace is placed onto the reactor so that location of the catalyst layer is in the middle of uniform temperature profile of the furnace.
• the carrier gas line with manual injection block is connected to the upper end of the reactor and the reactor is flushed with carrier gas through pressure release valve.
• the carrier gas flow rate, split ratio and sample splitting between capillary column and pulse mode measurement are adjusted with mass flow controllers.
• Reaction pressure is adjusted manually with a needle valve connected to the split gas outlet. After test temperature has exceeded the value of setting point and stabilised and the pre-treatment steps of catalyst are carried out the test reaction is started by manual or sample loop injection of the feed into the reactor.
• the reactor tube includig coked catalyst is removed from test unit and connected to the adapter unit of coke measurement equipment.
• the amount of coke deposited on the catalyst is measured with pulse method (pulses of oxygen/helium mixture) using a suitable highly sensitive method, for example methanation for detection of carbon-monoxide and carbon-dioxide as methane.
• pulse method pulse of oxygen/helium mixture
• suitable highly sensitive method for example methanation for detection of carbon-monoxide and carbon-dioxide as methane.
• Analytical instruments are controlled and data is collected with commercial soft- ware using a personal computer. Hydrogen and coke amounts are calculated using external calibration.
• MAT-equipment is commercial equipment suited for the comparison of different FCC (Fluid Catalytic Cracking) catalysts for catalytic cracking of heavy hydrocarbons.
• FCC Fluid Catalytic Cracking
• the combination of a reactor and an oven with a GC in testing of catalysts for the catalytic cracking reactions gives several superior features compared to MAT with respect to the process variables and analytical techniques.
• the gas phase sample is collected to a gas pipette during the experiment and the liquid phase sample is separated as a condensate. Therefore two separate analyses are needed. Furthermore, the samples of average nature are collected during rather long reaction time (20—75 s), while the activity of the catalyst declines during the experiment due to coking. With the ETC-equipment according to the invention the product gas is splitted to two sample flows with capillaries and analysed simultaneously and thus pulse mode, hydrogen response and compound analysis are obtained. Further, because of the very short contact time the catalyst maintains its activity during the experiment.
• the ETC- equipment In testing catalyst performance several variables, for example temperature, catalyst to oil ratio, residence time and cumulative amount of the feed are used. In the ETC- equipment these variables may be varied in considerably larger ranges than in MAT. In the ETC-equipment the lowest possible temperature for the liquid feeds is determined by the boiling point of the feed and for the gas feeds temperature may be lower than 100 °C. For example, for a gas oil feed the temperature may be between 20—900 °C. Catalyst to oil ratio may be from zero to 300.
• the residence times may be varied by adjusting carrier gas and split gas volume flows, in the equipment according to th invention the range of the residence times is usually from 0.01 s to 0.1 s.
• compound level resolution can be achieved with residence times 0.01—0.3 s.
• the volume of the liquid feed injected may be varied in the range of 0.1—1.0 ⁇ .1 without having any problems with temperature control.
• the regeneration of the catalyst after the cracking reactions may be carried out by pulse method.
• the cumulative amount of the coke formed during the reaction is obtained by summing up the formed CO and CO 2 .
• the kinetics of the coke combustion may also be evaluated by analyzing the formed CO and CO 2 after each pulse.
• the catalyst is regenerated after the experi- ment and the cumulative CO 2 amount is analyzed by IR-detector.
• CO and CO 2 are first converted to methane and then analyzed by FID which is several orders of magnitude more sensitive method than IR.
• Thermal cracking was studied by filling the reactor with 20 mg of inert material (Inert Microspheres MS-3X, same material was used with the catalysts to get the needed catalyst amount in the bed) and with quartz wool.
• the reactor material was quartz glass and the feed a light gas oil with boiling range between 221—420 °C (96 % , gas oil 1).
• thermal reactions are negligible below the temperature of 600 °C. Therefore, in order to study the catalytic reactions alone it is favorable to keep the temperature below this value.
• thermal cracking is always associated with catalytic cracking and the separation of these two phenomena is difficult because of the complexity of the interactions between the molecules involved in these reactions.
• Catalytic cracking experiments were carried out as a function of temperature, catalyst to oil ratio and residence time.
• the gas oils used were light gas oil with boiling range between 221—420 °C (96 % , gas oil 1) and 227—530 °C (96 %, gas oil 2). Temperature was varied between 400—650 °C, catalyst to oil ratio between 0—29.8 and residence time between 0.03—0.09 s.
• the amount of injected oil was always 0.5 ⁇ l (0.43 mg) and the catalysts and zeolites used were commercial equilibrium catalysts ans zeolite catalysts containing rare earth elements.
• Deactivation of cracking catalyst was studied by repeating the injection step several times (1, 2, 3, 10, 20 and 30) at the same conditons and taking samples into compound analysis from the last injection. Experiments were carried out at temperature of 600 °C, catalyst to oil -ratio 11.2 and residence time 0.055 s.
• the feed oil was light gas oil with boiling range beween 221—420 °C (96 % , gas oil 1).
• the amount of injected oil was always 0.5 ⁇ l (0.43 mg) and the catalysts used was commercial zeolite catalyst containing rare earth elements.
• Scale of time on stream was 0.055—1.65 s. Cumulative amount of coke was measured after each test and final coke amount was calculated as a difference between last two injections from measured cumulative results. The cumulative results are shown in Table 10 and final results are shown in Table 11.
• the cumulative amount of coke increases as a function of time on stream and the deactivation of catalyst can be seen as a decrease of conversion and LPG-yield.
• the formation of coke in course of deactivation decreases.
• the yield of coke during first 0.055 is 2.25 wt but after the activation period (1.6 s) on stream formed amount of coke is only 0.06 wt%.

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Citations (2)

• 1998
  • 1998-05-15 FI FI981088A patent/FI106409B/fi active
• 1999
  • 1999-05-10 CA CA002331507A patent/CA2331507A1/en not_active Abandoned
  • 1999-05-10 AU AU40420/99A patent/AU4042099A/en not_active Abandoned
  • 1999-05-10 WO PCT/FI1999/000382 patent/WO1999060396A1/en active Application Filing
  • 1999-05-10 CN CN 99806228 patent/CN1301346A/zh active Pending
  • 1999-05-10 EP EP99923615A patent/EP1078255A1/en not_active Withdrawn

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