A kind of technique that is diesel oil by methanol conversion
Technical field
The invention provides a kind of technique that is diesel oil by methanol conversion, be specifically related to a kind of processing method that dual-function catalyst is diesel oil by methanol conversion of using.
Background technology
In chemical reaction, can be with the generation of heat release or endothermic process.Solving the heat problem of transmission in reaction process, is one of groundwork of chemical production technical.
Methanolysis is that the reaction (CH3OH → CO+2H2) of synthetic gas is the reaction of a heat absorption.From thermodynamics, consider, high temperature is conducive to methyl alcohol to carry out to the direction that is decomposed into synthetic gas.And through the synthetic process of producing diesel component of Fischer-Tropsch, be the process of a heat release by synthetic gas, cryogenic high pressure is conducive to the synthetic diesel oil of producing of Fischer-Tropsch, in actual production operating process, Fischer-Tropsch is synthetic to carry out between 200 ℃ to 250 ℃, and takes reaction heat out of reactor by various heating picking process.
The synthetic gas that methanolysis is obtained is through the synthetic diesel oil that changes into of Fischer-Tropsch, this operational path is in the relatively oversaturated situation in coal methyl alcohol processed market, a part of methanol conversion can be become to diesel oil fuel, form one parallel mutually with preparing gasoline by methanol technique, widen the novel process of the application surface of Coal Chemical Industry.This technique needs the catalyzer synergy of two kinds of effects, namely carbinol resolving catalyst and fischer-tropsch synthetic catalyst, and dual-function catalyst is a kind of approach that realizes this technique.The method of preparing dual-function catalyst has multiple, has plenty of the component with different catalysiss is evenly mixed to moulding, powder blend aftershaping or the preparation of total immersion stain for example.The catalyzer of preparing by the way, between wherein each kind of component, reciprocal influence effect cannot be avoided, often the interaction between each component has changed the function of original active ingredient existing with independent form, the function that is to say the catalyzer forming after mixing is not the original stack of catalysis separately, but the change of matter has occurred.Obviously for methanolysis preparing synthetic gas again Fischer-Tropsch synthetic the technique of diesel oil, such method for preparing catalyst is inappropriate.And the catalyzer with nucleocapsid structure prepared by the method that the another kind of method of preparing dual-function catalyst is employing rolling moulding.In the process of rolling moulding, different time adds the powder that contains different activities component, can in granules of catalyst, form the structure with radially layered, different activities component is distributed in different radial depths, this has also just formed the different zones in same granules of catalyst with multiple catalysis, and between the active ingredient of difference in functionality, only have the attaching space of a sphere, therefore between different active ingredients influence each other very little.Such preparation method is favourable for Methanol for diesel oil.Moreover, because endothermic process and the synthetic exothermic process of Fischer-Tropsch of methanolysis is limited in carrying out in same granules of catalyst, the coupling process of Process of absorption or liberation of heat also will inevitably improve equilibrium conversion and the selectivity of product of reaction.
Summary of the invention
The object of the present invention is to provide a kind of can be the processing method that is rich in the high-quality diesel oil of straight chain hydrocarbon by methanol conversion.The catalyzer using in this technique is to adopt the method for rolling moulding to prepare, and in moulding process, has introduced the auxiliary agent with heat conduction function, and this catalyzer kernel is the component with Fischer-Tropsch complex functionality, and outer shell is the component with methanolysis function.
Methyl alcohol being changed into the process of diesel oil, is the consecutive process being cascaded by two reactions in fact, is first that methyl alcohol is decomposed into synthetic gas on catalyzer, is and then that synthetic gas changes diesel oil into through Fischer-Tropsch synthesis.The catalyzer of a kind of eggshell type provided by the invention has the ability of decomposing the ability that methyl alcohol is synthetic gas and synthetic gas being converted into diesel oil, so this catalyzer provided by the invention is to have bifunctional catalyzer simultaneously.
Methanolysis is that the reaction of synthetic gas is the reaction of a heat absorption, and synthetic gas is the process of a heat release through the synthetic process that changes diesel component into of Fischer-Tropsch, the present invention is exactly the method by roller forming, the component of two kinds of catalysiss is incorporated into same catalyst particles intragranular, and make them in each self-catalysis of performance, the reaction heat that allows the methanol decomposition reaction of carrying out in kernel utilize Fischer-Tropsch in shell to discharge in synthetic, realized the coupling of heat absorption and release process, thereby when reducing whole process energy consumption, also improved the selectivity of equilibrium conversion and target product.Therefore, the catalyzer of this eggshell type provided by the invention, not only has double-function catalyzing performance, also has the heat exchange function of coupling Process of absorption or liberation of heat process.
Egg-shell catalyst particle provided by the invention is in the process of rolling moulding, the powder with the active ingredient of different catalysiss successively adds according to time sequence, first be that the powder with the component of Fischer-Tropsch complex functionality is added in nodulizer together with heat conduction auxiliary agent, the thickness forming when this component reaches after required numerical value, with the powder with the component of methanolysis function, continue the moulding of rolling together with heat conduction auxiliary agent again, reach after required diameter to particle, moulding completes.
The active ingredient with Fischer-Tropsch complex functionality mainly comprises that Fe and Co etc. have the metal component of Fischer-Tropsch composite reactive, and what have methanolysis function can be the metal components such as Cu, Zn.
While using this dual-function catalyst, iff the synthetic gas that utilizes methanolysis to produce, by diffusion, entering into granules of catalyst kernel, to carry out Fischer-Tropsch synthetic again, can cause the synthetic heat release of the heat absorption of methanolysis and Fischer-Tropsch not mating in time, so that affect the effect of whole consecutive reaction.Therefore,, in the first stage of reaction, need first to pass into the parallel feeding of synthetic gas (gas mixture of CO and H2) and methyl alcohol in reactor.For example, start only to pass into synthetic gas, and not charging of methyl alcohol (or methyl alcohol proportion is little), when the Fischer-Tropsch synthesis in kernel portion proceeds to a certain degree, pass into again methanol feedstock, and progressively improve methyl alcohol proportion in combined feed total feed, until synthetic gas inlet amount is zero.While improving the ratio of methyl alcohol in charging, the rate-controlling that methyl alcohol ratio improves is between per hour 7% to per hour 45%.
The invention provides a kind of technique that is diesel oil by methanol conversion, owing to using a kind of dual-function catalyst with heat exchange function, make this processing method simply effective.
Embodiment
Below in conjunction with embodiment, the present invention is further detailed.
The following examples are only for the present invention that explains in detail, and limit the scope of the invention never in any form.
Embodiment 1
The aqueous nitric acid that the aluminium colloidal sol that the density of take is 0.7g/ml and concentration are 5% is mixed with tackiness agent (wherein aluminium colloidal sol and aqueous nitric acid volume ratio are 15:1), by the uniform cobalt oxide of ground and mixed, aluminum oxide and graphite (Co:Al=1:9 mol ratio, the mass ratio of graphite and Co and Al oxide compound is 1:100) powder pour in A nodulizer, the tackiness agent spraying into atomization contacts, rolling moulding, when the spherolite radius of moulding reaches 2.5mm, spherolite enters in B nodulizer after rolling out from A nodulizer, in B nodulizer, there is the uniform cupric oxide of ground and mixed, zinc oxide and aluminum oxide, and the powder of graphite (Cu:Zn:Al=1:1:6 mol ratio, graphite and Cu, the mass ratio of Zn and Al oxide compound is 1:5), under the tackiness agent effect spraying in atomization, continue to roll and be formed into the spherical of diameter 10mm, leave B nodulizer.Now there is the Active components distribution of Fischer-Tropsch complex functionality in the kernel area of radius≤2.5mm, and the Active components distribution with methanolysis function at radius in the shell region between 2.5mm to 5mm, heat conduction auxiliary agent graphite is to be distributed in whole particle.The roasting at 400 ℃ of spheroidal particle after moulding, after 2 hours, is obtained to spherical catalyst particle.Such granules of catalyst is packed in the fixed-bed reactor that internal diameter is 80mm, the beds that height of formation is 320mm, initial time, with air speed 1000 h
-1in reactor, pass into synthetic gas (H2:CO=2 volume ratio), and start from scratch and increase the ratio of methyl alcohol in charging (total mole number with methyl alcohol and synthetic gas measures total inlet amount with per hour 10% speedup, the ratio that methyl alcohol accounts for combined feed total feed is the molecular fraction that methyl alcohol accounts for total feed), 10 hours rear feedings are all methyl alcohol, at 225 ℃, under the reaction conditions of 5MPa, while reacting 24 hours, methanol conversion is 30%, all in product, CO2 accounts for 25%, in hydrocarbon product, methane selectively is 11%, and C10 is above, (with the above component of C10, represent diesel oil here, selectivity down together) reaches 52%.
Embodiment 2
Catalyzer is with embodiment 1.Such granules of catalyst is packed in the fixed-bed reactor that internal diameter is 80mm, the beds that height of formation is 320mm, initial time, with air speed 1000 h
-1in reactor, pass into synthetic gas (H2:CO=2 volume ratio), and start from scratch and increase the ratio of methyl alcohol in charging (total mole number with methyl alcohol and synthetic gas measures total inlet amount with per hour 45% speedup, the ratio that methyl alcohol accounts for combined feed total feed is the molecular fraction that methyl alcohol accounts for total feed), 2 hours rear feedings are all methyl alcohol, at 215 ℃, under the reaction conditions of 5MPa, while reacting 24 hours, methanol conversion is 25%, all in product, CO2 accounts for 26%, in hydrocarbon product, methane selectively is 13%, and more than C10 selectivity reaches 48%.