CN103418393A - Catalyst for Fischer-Tropsch synthetic heavy hydrocarbons and preparation method thereof - Google Patents

Abstract

The invention relates to a catalyst for Fischer-Tropsch synthetic heavy hydrocarbons and a preparation method thereof, and mainly solves the problems that in the prior art, because Fischer-Tropsch synthesis reaction is a strongly exothermic reaction, when a fixed bed is used, heat removal of the reaction is difficult, the temperature is easy to fly up, and the catalyst is easy to deactivate; and when a fluidized bed is used, the selectivity of the heavy hydrocarbons (namely hydrocarbons with more than 5 carbon atoms) is low. According to the invention, a technical scheme is used to well solve the problems, and the technical scheme is as follows: an iron-based fluidized bed catalyst is used, wherein the iron-based fluidized bed catalyst adopts at least one substance selected from Si oxide or Al oxide to use as a carrier, and comprises an active component comprising a composition shown as a chemical formula of Fe[100]Ca[a]Zn[b]La[c]O[x] by atomic ratio; a synthetic gas is used as a raw material, and under the conditions of the pressure of 0.5-10MPa, the reaction temperature of 200-600 DEG C, the reaction space velocity of 100-8000 h<-1>, and the raw material gas H2/CO ratio of 0.1-5.0:1, the raw material contacts with the iron-based fluidized bed catalyst in the fluidized bed for reaction to produce the heavy hydrocarbons. The catalyst can be used in industrial production of fluidized bed Fischer-Tropsch synthesis reactions.

Description

The Catalysts and its preparation method of Fischer-Tropsch synthesis of heavy hydrocarbon

Technical field

The present invention relates to a kind of Catalysts and its preparation method of Fischer-Tropsch synthesis of heavy hydrocarbon.

Background technology

The method that synthesis gas is converted into to liquid hydrocarbon through catalyst action is that nineteen twenty-three is by Germany scientist Frans Fischer and Hans Tropsch invention, be called for short F-T synthetic, be that the heterogeneous catalysis hydrogenation occurs CO on metallic catalyst, generate and take the process that linear paraffin and alkene is main mixture.Germany just carried out research and development in the twenties in last century, and had realized industrialization in 1936, after World War II because closing with the petroleum industry competition economically; South Africa has abundant coal resources, but the petroleum resources plaque is weary, and be subject to for a long time the restriction of international community's economy and political sanction, force its Development of Coal oils preparation industry technology, and built up in 1955 the coal-based F-T artificial oil factory (Sasol-1) that First production capacity is ten thousand tons of product/years of 25-40.

Twice world oil crisis of 1973 and 1979, cause world's crude oil price to fall and swing fluctuating, big rise and big fall, the consideration based on the Strategic Technology deposit, and the F-T synthetic technology is aroused the interest of industrialized country again.1980 and nineteen eighty-two, two the coal-based artificial oil factories that in succession build up again and gone into operation of South Africa Sasol company.But plummeting of World oil price in 1986, postponed the F-T synthetic technology heavy industrialization process national at other.

Twentieth century is since the nineties, and petroleum resources are shortage and in poor quality increasingly, and coal and natural gas proved reserves but constantly increase simultaneously, and the GTL technology causes extensive concern again.Through the development of decades, Fischer-Tropsch catalyst has also obtained significant progress, and catalyst commonly used at present is divided into two large classes active component: ferrum-based catalyst and cobalt-base catalyst.According to the difference of adopted catalyst and the difference of target product, the Fischer-Tropsch synthesis device is divided into again fixed bed reactors, fluidized-bed reactor and paste state bed reactor.The fixed bed reactors complex structure, expensive, remove the heat difficulty, the production capacity of whole device is lower.The characteristics of slurry state bed are that reaction temperature is lower, be easy to control, but conversion ratio are lower, and the liquid-solid separation that product mostly is slurries in high-carbon hydrocarbon and reactor is comparatively difficult.The characteristics of fluidized-bed reactor are that temperature is higher, and conversion ratio is higher, do not have the difficulty of liquid-solid separation, and product mostly is lower carbon number hydrocarbons; Construction and operating cost are lower, and low pressure reduction has been saved a large amount of compression expenses, and are more conducive to except the heat of emitting in dereaction, and simultaneously because gas line speed is low, wear problem is less, and this makes long-term running become possibility.

Iron catalyst has advantages of a lot, as highly selective obtains low-carbon alkene, prepares high-octane gasoline etc., and ferrum-based catalyst also has the characteristics that operating condition is wide, the product adjustability is large in addition.The preparation method of Fe-series catalyst mainly contains three kinds: the precipitation method (precipitated catalyst), sintering process (sintered catalyst) and oxide mixing method (fused iron catalyst).The currently reported synthetic molten iron type that the mostly is catalyst of fluid bed Fischer-Tropsch that is applied to, as mentioned a kind of molten iron type catalyst synthetic for Fischer-Tropsch in patent CN1704161A, catalyst by the oxide of Fe, Al, K, Ca and on a small quantity other oxide form, 280 ℃ of reaction temperatures, reaction pressure 6.0MPa, catalyst loading 500 hours ^-1, the raw material proportioning (mole) H ₂Under the condition of/CO=1.5, the CO conversion ratio be 93.4%, C5+ hydrocarbon be selectively 60.2%.But be that the standby catalyst of molten iron legal system or the precipitation method prepare Fluidized Multicomponent Metallic Oxides Catalysts and all have complex process, energy consumption is high, the shortcoming that the catalyst manufacturing cycle is long.

Summary of the invention

One of technical problem to be solved by this invention be in prior art, exist because Fischer-Tropsch synthesis is strong exothermal reaction, while using fixed bed, the heat difficulty is removed in reaction, easily temperature runaway, make the easy inactivation of catalyst; While using fluid bed, the selective low problem of petrol and diesel oil, provide a kind of new Fischer-Tropsch to synthesize the ferrum-based catalyst of light hydrocarbon.This catalyst has the fluidized-bed reactor that is applicable to and is not limited to middle high temperature, low-carbon alkene and the high advantage of gasoline, diesel compositional selecting.Two of technical problem to be solved by this invention is to provide the preparation method of the required catalyst-compatible of one of a kind of and technical solution problem.

As follows for solving the problems of the technologies described above a technical solution used in the present invention: a kind of ferrum-based catalyst of Fischer-Tropsch synthesis of heavy hydrocarbon, it is carrier that this catalyst be take at least one of the oxide that is selected from Si or Al, active component contains with atomic ratio measuring, the composition that chemical formula is following:

Fe ₁₀₀Ca _aZn _bLa _cO _x?

In formula, the span of a is 0.1～10.0;

The span of b is 5.0～60.0;

The span of c is 0. 1～15.0;

X meets the required oxygen atom sum of each element valence in catalyst;

The carrier consumption is 30～70% of catalyst weight by weight percentage.

The value preferable range that the value preferable range that in technique scheme, the value preferable range of a is 1.0～8.0, b is 10.0～50.0, c is 1.0～10.0, and carrier consumption preferable range is 40～60% of catalyst weight by weight percentage.

As follows for solving the problems of the technologies described above two the technical solution used in the present invention: the preparation method of the ferrum-based catalyst of Fischer-Tropsch synthesis of heavy hydrocarbon comprises following processing step:

(1) by the aequum soluble ferric iron salt solution I of making soluble in water,

(2) aequum solubility La salt is dissolved in hot water water and makes the solution II,

(3) by the soluble-salt of aequum Ca and the Zn solution III of making soluble in water,

(4) solution I solution, II solution, III solution mixing system are become to the mixed solution IV,

(5) in 70-100 ℃ of bath, aequum is selected to SiO ₂Or Al ₂O ₃In at least one colloidal sol join in the solution IV, mix making beating, the pH value that simultaneously adds acid-base modifier to regulate slurry is 1～5, obtaining solid content is 15～45wt% slurry V,

(6) send into the spray dryer spray shaping after the slurry V is cooled to 20～60 ℃, then, 400～750 ℃ of roasting temperatures 0.15～6 hour, obtain microspheroidal fluid bed iron-base fischer-tropsch synthesis catalyst.

The manufacture method of the catalyst in the inventive method there is no specific (special) requirements, can be undertaken by well-established law.At first the catalyst each component is made to solution, then be mixed and made into slurry with carrier, the spray-dried microspheroidal that is shaped to, finally make catalyst at 450-700 ℃ of roasting 0.5-5 hour.The preparation of slurry is preferably undertaken by the CN1005248C method.

The raw material of manufacturing catalyst of the present invention is:

Ferric nitrate or ferric sulfate for the iron component in catalyst.

The most handy its nitrate of all the other components, hydroxide maybe can be decomposed into the salt of oxide.

Raw material as carrier silica can be used Ludox, silicon gel or both mixtures.If use Ludox, its quality will meet the requirement of CN1005248C.

Spray dryer available pressure formula, two streamings or centrifugal turntable formula, but, with centrifugal better, can guarantee that the catalyst of making has good size distribution.

The roasting of catalyst can be divided into two stages and carry out: the decomposition of each element salt and high-temperature roasting in catalyst.The catabolic phase temperature is preferably 200～300 ℃, and the time is 0.5～2 hour.Sintering temperature is 500～800 ℃, is preferably 550～700 ℃; Roasting time is 20 minutes to 2 hours.Above-mentioned decomposition and roasting are carried out respectively in two roasters, also can in a stove, be divided into two zones, also can in the continous way rotary roasting furnace, complete simultaneously and decompose and roasting.To pass into appropriate air in catalyst decomposes and roasting process, to generate Catalytic active phase.

The reducing condition of the catalyst that the present invention makes: pressure is between 0.05～5MPa, is preferably 0.1～4MPa; Reducing gas can be used hydrogen, carbon monoxide or synthesis gas, while using synthesis gas, and its H ₂/ CO mol ratio is 0.1～6.0, is preferably 0.2～6.0; The load of reducing gases is 100～8000 hours ^-1, be preferably 500～6000 hours ^-1Reduction temperature is 200～600 ℃, is preferably 220～500 ℃; Recovery time is 1～100 hour, is preferably 6～72 hours.

The reaction condition of the catalyst that the present invention makes: pressure is between 0.5～10MPa, is preferably 1～8MPa; Reaction temperature is 200～600 ℃, is preferably 220～500 ℃; Catalyst loading is 100～8000 hours ^-1, be preferably 500～6000 hours ^-1H in unstripped gas ₂/ CO mol ratio is 0.1～5.0, is preferably 0.5～3.0.

Because the present invention adopts fluidized-bed process, therefore solved in prior art because Fischer-Tropsch synthesis is strong exothermal reaction, while using fixed bed, the heat difficulty is removed in reaction, and easy temperature runaway makes the problem of the easy inactivation of catalyst; In addition due to the lanthanum of introducing in catalyst, zinc as catalyst promoter, promoted the dispersion of catalyst activity component at catalyst surface, thereby be conducive to improve the activity of catalyst, solved when using fluid bed the selective low problem of heavy hydrocarbon.Use method of the present invention, 200～600 ℃ of reaction temperatures, reaction pressure 0.5～10MPa, catalyst loading 100～8000 hours ^-1, the raw material proportioning (mole) H ₂Carry out Fischer-Tropsch synthesis under the condition of/CO=0.1～5.0:1, the CO conversion ratio can reach 91.2%, in product heavy hydrocarbon selectively can reach 70.8%, obtained technique effect preferably.

Below by embodiment, the present invention is further elaborated.

The specific embodiment

[embodiment 1]

451.5 gram ferric nitrates are added to water 500 grams and dissolve, obtain material (I), 12.9 gram lanthanum nitrates add water 20 gram heating for dissolving, obtain material (II), 15.7 gram calcium nitrate and 99.72 gram zinc nitrates, in same container, add 200 gram water, stirring and dissolving obtains material (III).

Material I, II, III are mixed, under agitation add the Ludox material that 625 gram weight concentration are 40%, the acidity of with ammoniacal liquor, regulating above-mentioned slurry makes the pH=6.0 of mixed slurry, obtain slurry after fully stirring, according to well-established law, the slurry of making is carried out to the framboid moulding in spray dryer, at internal diameter, be finally 89 millimeters, in the rotary roasting furnace that length is 1700 millimeters (89 * 1700 millimeters of φ), in 500 ℃ of roastings 2.0 hours, make and consist of:

50%?Fe ₁₀₀Ca _6.0Zn _30.0La _4.0O _x＋50%SiO ₂。

Catalyst.

Prepared catalyst carries out at reducing condition:

400 ℃ of temperature

Pressure 3.0MPa

Loaded catalyst 100 grams

Catalyst loading 4000 hours ^-1

Reducing gases H ₂/ CO=2/1

24 hours recovery times

Reduced, then carried out under the following conditions Fischer-Tropsch synthesis:

38 millimeters fluidized-bed reactors of φ

280 ℃ of reaction temperatures

Reaction pressure 2.0MPa

Loaded catalyst 100 grams

Catalyst loading 3000 hours ^-1

The raw material proportioning (mole) H ₂/ CO=2/1

The experimental result of Fischer-Tropsch synthesis is listed in table 1.

[embodiment 2～6]

Adopt method preparation substantially the same manner as Example 1 to have the different catalyst that form, gained catalyst numbering and composition are respectively:

Embodiment 1 50% Fe ₁₀₀Ca _6.0Zn _30.0La _4.0O _x+ 50%SiO ₂

Embodiment 2 60% Fe ₁₀₀Ca _1.0Zn _50.0La _6.0O _x+ 40%Al ₂O ₃

Embodiment 3 45% Fe ₁₀₀Ca _8.0Zn _25.0La _2.0O _x+ 55%SiO ₂

Embodiment 4 50% Fe ₁₀₀Ca _5.0Zn _40.0La _1.0O _x+ 50% (50%SiO ₂+ 50%Al ₂O ₃)

Embodiment 5 40% Fe ₁₀₀Ca _4.0Zn _20.0La _10.0O _x+ 60%SiO ₂

Embodiment 6 55% Fe ₁₀₀Ca _5.5Zn _10.0La _5.0O _xO _x+ 45%SiO ₂

Prepared catalyst carries out Fischer-Tropsch synthesis under following reaction condition, the results are shown in Table 1.

[comparative example 1～3]

Adopt method preparation substantially the same manner as Example 1 to have the different catalyst that form, gained catalyst numbering and composition are respectively:

Comparative example 1 50% Fe ₁₀₀Ca _4.0Zn _30.0O _x+ 50%SiO ₂

Comparative example 2 50% Fe ₁₀₀Ca _5.0La _5.0O _x+ 50%SiO ₂

Comparative example 3 50% Fe ₁₀₀Zn _40.0La _6.0O _x+ 50%SiO ₂

Prepared catalyst carries out Fischer-Tropsch synthesis under following reaction condition, and result is also listed in table 1.

The evaluation result of table 1 embodiment catalyst

[embodiment 7]

Press each step and the condition Preparation and evaluation catalyst of embodiment 1, just reaction temperature is 250 ℃, and its appreciation condition is listed in table 2, and evaluation result is listed in table 3.

[embodiment 8-14]

Press each step and the condition Preparation and evaluation catalyst of embodiment 1, just change a certain appreciation condition wherein, its appreciation condition is listed in table 2, and evaluation result is listed in table 3.

The appreciation condition of table 2 embodiment 7-14

The evaluation result of catalyst under table 3 different evaluation condition

Claims (3)

1. the ferrum-based catalyst of a Fischer-Tropsch synthesis of heavy hydrocarbon, this catalyst take in the oxide that is selected from Si or Al at least one be carrier, active component contains with atomic ratio measuring, the composition that chemical formula is following:

Fe ₁₀₀Ca _aZn _bLa _cO _x?

In formula, the span of a is 0.1～10.0;

The span of b is 5.0～60.0;

The span of c is 0. 1～15.0;

X meets the required oxygen atom sum of each element valence in catalyst;

The carrier consumption is 30～70% of catalyst weight by weight percentage.

2. the preparation method of the ferrum-based catalyst of Fischer-Tropsch synthesis of heavy hydrocarbon claimed in claim 1 comprises following processing step:

(1) by the aequum soluble ferric iron salt solution I of making soluble in water,

(2) aequum solubility La salt is dissolved in hot water water and makes the solution II,

(3) by the soluble-salt of aequum Ca and the Zn solution III of making soluble in water,

(4) solution I solution, II solution, III solution mixing system are become to the mixed solution IV,

(5) in 70-100 ℃ of water-bath, aequum is selected to SiO ₂Or Al ₂O ₃In at least one colloidal sol join in the solution IV, mix making beating, the pH value that simultaneously adds acid-base modifier to regulate slurry is 1～5, obtaining solid content is 15～45wt% slurry V,

(6) send into the spray dryer spray shaping after the slurry V is cooled to 20～60 ℃, then, 400～750 ℃ of roasting temperatures 0.15～6 hour, obtain microspheroidal fluid bed iron-base fischer-tropsch synthesis catalyst.

3. prepare according to claim 2 the preparation method of fluid bed with iron-base fischer-tropsch synthesis catalyst, it is characterized in that sintering temperature is preferably 450～700 ℃, roasting time is preferably 0.5～5 hour.