阅读说明：本技术 一种催化生物质合成气转化制备液态石油气的方法 (Method for preparing liquid petroleum gas by catalyzing conversion of biomass synthesis gas ) 是由 马文超 拉塔 陈冠益 钟磊 颜蓓蓓 于 2019-11-28 设计创作，主要内容包括：本发明公开了一种催化生物质合成气转化制备液态石油气的方法。该发明首先以Fe<Sub>3</Sub>O<Sub>4</Sub>与ZSM-5为反应物,以二氧化硅为粘合剂,通过物理包裹法合成Fe<Sub>3</Sub>O<Sub>4</Sub>@ZSM-5核壳材料。反应采用固定床反应器,在不同还原气氛下将Fe<Sub>3</Sub>O<Sub>4</Sub>@ZSM-5原位还原成Fe@ZSM-5催化材料。随后通入生物质合成气,直接催化转化合成液态石油气。该方法所述催化剂制备简单,成本低廉,且表现出很好的催化活性。其中在CO还原条件下得到的Fe@0.5wt.％ZSM-5催化剂,达到81.6％的CO转化率以及42％的液态石油气选择性。(The invention discloses a method for preparing liquefied petroleum gas by catalyzing conversion of biomass synthesis gas. The invention firstly uses Fe 3 O 4 Synthesizing Fe with ZSM-5 as reactant and silicon dioxide as adhesive by physical wrapping method 3 O 4 @ ZSM-5 core-shell material. The reaction adopts a fixed bed reactor, and Fe is reacted in different reducing atmospheres 3 O 4 @ ZSM-5 is reduced in situ to form Fe @ ZSM-5 catalytic material. Then introducing biomass synthesis gas, and directly carrying out catalytic conversion to synthesize the liquid petroleum gas. The catalyst prepared by the method is simple to prepare, low in cost and good in catalytic activity. Wherein the Fe @0.5 wt.% ZSM-5 catalyst obtained under CO reduction conditions achieved a CO conversion of 81.6% and a liquid petroleum gas selectivity of 42%.)

1. A method for preparing liquefied petroleum gas by catalyzing conversion of biomass synthesis gas is characterized by comprising the following steps:

firstly, weighing Fe with the size of 20-40 meshes₃O₄Adding the mixture into a silica solution with the mass percent of 40 wt.% for wetting, then adding a ZSM-5 molecular sieve into the silica solution, and vigorously shaking the mixture until the mixture is uniform, wherein the ZSM-5 molecular sieve is mixed with Fe₃O₄Is 0.2-1 wt.%, Fe₃O₄The mass ratio of the silicon dioxide to the silicon dioxide is 1: 2-2: 1;

secondly, putting the uniformly mixed solution into a vacuum drying oven for drying to obtain a solid; then putting the dried solid into a muffle furnace to calcine and remove silicon dioxide to obtain Fe₃O₄@ ZSM-5 catalyst solid precursor;

third, 1.0g of Fe₃O₄The @ ZSM-5 catalyst precursor is placed in a constant temperature area of a reaction tube in a fixed bed reactor, heated to 300 ℃ at the speed of 2.0 ℃/min and reduced for 10 hours in a reducing atmosphere, and the flow rate of the reducing gas is 50 mL/min; after the reduction is finished, the biomass synthesis gas raw material is switched and introduced into the fixed bed reactor, and the reaction airspeed is 1500h^-1Then collecting the downstream product of the reaction tube, namely the liquid petroleum gas; the biomass synthesis gas comprises the following raw materials: h₂60mol.％、CO 30mol.％、N₂5mol.％、CO₂5mol.％。

2. The method for preparing liquefied petroleum gas by catalyzing conversion of biomass synthesis gas as claimed in claim 1, wherein: in the second step, the drying temperature is 100 ℃, the drying time is 4 hours, the calcining temperature is 500 ℃, and the calcining time is 4 hours.

3. The method for preparing liquefied petroleum gas by catalyzing conversion of biomass synthesis gas according to claim 1 or 2, wherein: the reducing gas is H₂CO or H₂And CO, wherein H is contained in the mixed gas₂/CO mol.％＝2:1。

Technical Field

The invention relates to a method for preparing liquefied petroleum gas by catalyzing biomass synthesis gas to be converted through a Fe @ ZSM-5 catalyst under different reducing atmosphere conditions.

Background

Liquefied Petroleum Gas (LPG) is an environment-friendly liquid fuel and has good application prospect. However, at present, liquefied petroleum gas is mainly derived from byproducts in paraffin-based oilfield associated gas and petroleum refining processes, and the yield of the liquefied petroleum gas cannot meet the increasing market demand.

The biomass energy is an energy form that solar energy is stored in biomass in a chemical energy form, biomass is gasified to obtain biomass synthesis gas, and the biomass synthesis gas is further subjected to Fischer-Tropsch synthesis catalytic conversion to prepare liquid petroleum gas, so that the biomass energy has a wider application prospect.

The one-step preparation of liquid petroleum gas from biomass synthesis gas can be realized on a composite catalyst consisting of a methanol synthesis catalyst and a molecular sieve. Especially, a large-aperture molecular sieve composite catalyst represented by ZSM-molecular sieve shows higher liquid petroleum gas selectivity. The research group of the national university of kyushu, japan realized the selective conversion of the synthesized gaseous hydrocarbon liquid petroleum gas on a composite catalyst consisting of a methanol synthesis catalyst and a molecular sieve. Unlike the conventional industry where synthesis gas is directly produced into hydrocarbons. The process is free from the limitation that the carbon chain can be limited to 3-4 by the aperture size and the spatial structure of the molecular sieve, and the liquid petroleum gas is obtained with high selectivity. But the important problems faced by this process today are: the composite catalyst has poor stability and high production cost.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a method for preparing liquid petroleum gas by catalyzing the conversion of biomass synthesis gas with stable catalyst material and low cost.

The invention discloses a method for preparing liquefied petroleum gas by catalyzing conversion of biomass synthesis gas, which comprises the following steps:

firstly, weighing Fe with the size of 20-40 meshes₃O₄Adding the mixture into a silica solution with the mass percent of 40 wt.% for wetting, then adding a ZSM-5 molecular sieve into the silica solution, and vigorously shaking the mixture until the mixture is uniform, wherein the ZSM-5 molecular sieve is mixed with Fe₃O₄Is 0.2-1 wt.%, Fe₃O₄The mass ratio of the silicon dioxide to the silicon dioxide is 1: 2-2: 1;

secondly, putting the uniformly mixed solution into a vacuum drying oven for drying to obtain a solid; then putting the dried solid into a muffle furnace to calcine and remove silicon dioxide to obtain Fe₃O₄@ ZSM-5 catalyst solid precursor;

third, 1.0g of Fe₃O₄The @ ZSM-5 catalyst precursor is placed in a constant temperature area of a reaction tube in a fixed bed reactor, heated to 300 ℃ at the speed of 2.0 ℃/min and reduced for 10 hours in a reducing atmosphere, and the flow rate of the reducing gas is 50 mL/min; after the reduction is finished, the biomass synthesis gas raw material is switched and introduced into the fixed bed reactor, and the reaction airspeed is 1500h^-1Then collecting the downstream product of the reaction tube, namely the liquid petroleum gas; the biomass synthesis gas comprises the following raw materials: h₂60mol.％、CO 30mol.％、N₂5mol.％、CO₂5mol.％。

The invention has the beneficial effects that:

the catalyst Fe @ ZSM-5 is prepared by a physical wrapping method, the preparation method is simple, and the cost is low; the catalyst not only has a core-shell structure, but also has strong mechanical strength, and is beneficial to the improvement of the stability of the catalyst.

Using three different reducing gases (including H)₂CO and syngas), when the reducing atmosphere is CO, the catalytic effect of the Fe @0.5 wt.% ZSM-5 catalyst is optimal, the CO conversion in the raw material is 81.6%, and the selectivity of the liquid petroleum gas reaches 42%.

Drawings

FIG. 1 shows the CO conversion of different ZSM-5 mass ratios of Fe @ ZSM-5 catalyst and a comparative sample of Fe in different reducing atmospheres for the conversion of biomass synthesis gas. And (3) catalyst reduction conditions: 300 ℃, reaction conditions: 300 ℃, 2Mpa and the airspeed of 1500h^-1；

FIG. 2 shows the selectivity of Fe @ ZSM-5 catalyst for various ZSM-5 mass ratios and a comparative Fe to LPG. Reduction conditions are as follows: h₂Atmosphere, 300 ℃, reaction conditions: 300 ℃, 2Mpa and the airspeed of 1500h^-1；

FIG. 3 is a graph of the Fe @ ZSM-5 catalyst for different ZSM-5 mass ratios and the selectivity of comparative Fe to LPG. Reduction conditions are as follows: atmosphere of CO, 300 ℃, reaction conditions: 300 ℃, 2Mpa and the airspeed of 1500h^-1；

FIG. 4 is a graph of the Fe @ ZSM-5 catalyst for different ZSM-5 mass ratios and the selectivity of comparative Fe to LPG. Reduction conditions are as follows: mixed gas (H)₂Mol.% CO 2:1), 300 ℃, reaction conditions: 300 ℃, 2Mpa and the airspeed of 1500h^-1。

Detailed Description

In order to make the present invention more comprehensible, the technical solutions of the present invention are further described below with reference to specific embodiments, but the present invention is not limited thereto.

The invention discloses a method for preparing liquefied petroleum gas by catalyzing conversion of biomass synthesis gas, which comprises the following steps:

firstly, weighing Fe with the size of 20-40 meshes₃O₄Adding the mixture into a silica solution with the mass percent of 40 wt.% for wetting, then adding a ZSM-5 molecular sieve into the silica solution, and vigorously shaking the mixture until the mixture is uniform, wherein the ZSM-5 molecular sieve is mixed with Fe₃O₄Is 0.2-1 wt.%, Fe₃O₄The mass ratio of the silicon dioxide to the silicon dioxide is 1: 2-2: 1;

secondly, putting the uniformly mixed solution into a vacuum drying oven for drying to obtain a solid; then putting the dried solid into a muffle furnace to calcine and remove silicon dioxide to obtain Fe₃O₄@ ZSM-5 catalyst solid precursor. Preferably, the drying temperature is 100 ℃, the drying time is 4 hours, the calcining temperature is 500 ℃, and the calcining time is 4 hours.

Third, 1.0g of Fe₃O₄The @ ZSM-5 catalyst precursor is placed in a constant temperature area of a reaction tube in a fixed bed reactor, heated to 300 ℃ at the speed of 2.0 ℃/min and reduced for 10 hours in a reducing atmosphere, and the flow rate of the reducing gas is 50 mL/min; after the reduction is finished, the biomass synthesis gas raw material is switched and introduced into the fixed bed reactor, and the reaction airspeed (the biomass synthesis gas raw material is Fe)₃O₄The residence time of the @ ZSM-5 catalyst bed) is 1500h^-1And then collecting the product at the downstream of the reaction tube, namely the liquid petroleum gas. The biomass synthesis gas comprises the following raw materials: h₂60mol.％、CO 30mol.％、N₂5mol.％、CO ₂5 mol.%. The reducing gas is H₂CO or H₂And CO, wherein H is contained in the mixed gas₂/CO mol.％＝2:1。

Comparative example 1

Firstly, weighing Fe with the size of 20-40 meshes₃O₄Adding the mixture into a silica solution with the mass percent of 40 wt.% for wetting, and vigorously shaking the mixture until the mixture is uniformly mixed;

secondly, putting the uniformly mixed solution into a vacuum drying oven for drying to obtain a solid; then, placing the dried solid in a muffle furnace for calcining, and removing silicon dioxide to obtain Fe₃O₄A solid precursor of the catalyst. The drying temperature is 100 ℃, the drying time is 4h, the calcining temperature is 500 ℃, and the calcining time is 4 h.

Third, 1.0g of Fe₃O₄Placing the catalyst precursor in a constant temperature area of a reaction tube in a fixed bed reactor, heating to 300 ℃ at the speed of 2.0 ℃/min, and then reducing for 10h in a reducing atmosphere, wherein the flow rate of the reducing gas is 50 mL/min; fe after reduction₃O₄I.e., reduced to Fe control catalyst. Then, biomass synthesis gas raw material is switched and introduced into the fixed bed reactor, and the reaction airspeed is 1500h^-1And then collecting the product at the downstream of the reaction tube, namely the liquid petroleum gas. The biomass synthesis gas comprises the following components: h₂60mol.％、CO 30mol.％、N₂5mol.％、CO ₂5 mol.%, and the reducing gas is H₂。

When the reducing atmosphere is H₂The catalytic effect of Fe comparative sample is shown in fig. 1 and fig. 2, the raw material CO conversion is 77%, and the liquid petroleum gas selectivity is 28%.

Comparative example 2

The procedure was the same as in comparative example 1, except that the reducing gas was changed to CO.

When the reducing atmosphere is CO, the Fe comparative sample has the catalytic effect shown in figures 1 and 3, the CO conversion rate in the raw material is 55.9%, and the selectivity of the liquid petroleum gas is 36.9%.

Comparative example 3

Process and apparatusComparative example 1 the same as above except that the reducing gas was changed to a mixed gas (H)₂/CO mol.％＝2:1)。

When the reducing atmosphere is mixed gas, the catalytic effect of the Fe comparative sample is shown in figures 1 and 4, the CO conversion rate in the raw material is 81.4%, and the selectivity of the liquid petroleum gas is 32.4%.