CN102218324B - Catalyst for removing oxygen and improving quality of bio-oil and preparation method thereof - Google Patents

Abstract

The invention relates to a catalyst for catalytic upgrading of bio-oil and a preparation method thereof, comprising a catalyst active component and a catalyst carrier, characterized in that, in terms of mass percentage, the composition of the catalyst active component and the catalyst carrier is: NiO is 10 -32wt%; MoO ₃ is 5-18wt%; CoO is 5-15wt%; the rest is dolomite catalyst carrier. The invention has the advantage of adopting cheap and easy-to-obtain dolomite as the catalyst carrier, and the catalytic active component is a composite component of nickel, cobalt and molybdenum, which weakens the acidity and oxygen content of bio-oil. The catalyst is simple to prepare, high in strength, strong in catalytic activity, and reproducible, and can be used not only to prepare high-quality bio-oil from biomass, but also to produce hydrogen by catalytic reforming of bio-oil.

Description

Catalyst for deoxidation and upgrading of bio-oil and preparation method thereof

technical field

The invention relates to a bio-oil deoxidation and upgrading catalyst and a preparation method thereof, that is, a method for preparing a catalyst for high-quality liquid fuel by catalytic cracking conversion of biomass.

Background technique

Both at home and abroad attach great importance to the research of biomass cracking and liquefaction. The current rapid cracking technology has achieved satisfactory results in improving the yield of biomass liquefaction. Typical fast cracking reactors include fluidized bed, rotating conical bed, etc. Although the yield of biomass rapid pyrolysis bio-oil is high, it cannot be used as high-quality energy due to its complex composition, high oxygen content, and low calorific value. Converting renewable biomass resources into clean high-quality liquid fuels is crucial to alleviate my country's oil shortage is of great significance to ensure my country's energy security and sustainable development of the national economy.

Tar is an important component of bio-oil, and the efficiency of its conversion into light components is the key to the success of bio-oil upgrading technology. The research on bio-oil upgrading catalysts at home and abroad is gradually heating up, but according to the existing reports, there are still problems in the developed catalysts: (1) the strength and activity cannot be balanced; (2) the stability of the catalyst (anti-coking Performance, sulfur resistance) can not meet the needs of large-scale production of bio-oil, some catalysts with better stability are only the performance of catalytic gasification of one or two kinds of tar or bio-oil model compounds, for the actual bio-oil catalytic gas (3) More rare transition metals are used as cocatalysts to improve performance, but the cost performance of catalysts is reduced. In short, the catalysts currently developed often only achieve better performance parameters in one aspect, while ignoring or failing to take into account other performances, so they cannot meet the economic and technical requirements for catalytic upgrading of bio-oil.

At present, rapid biomass pyrolysis technology can obtain a high yield of liquid products, but the product composition is complex, the oxygen content is high, the calorific value is low, and the acidity is strong. These factors are obstacles to the application of bio-oil as a high-quality liquid fuel. In order to expand the application range of pyrolysis oil, it is necessary to improve the process, reduce the oxygen content, acidity and increase the composition of the oil phase, so as to improve the calorific value and other fuel properties. At present, the research on deoxygenation and upgrading of bio-oil is carried out in two steps, that is, the first step is to quickly crack the biomass, cool the bio-oil vapor to obtain crude oil, and obtain high-quality bio-oil by hydrodeoxygenation and other methods. Although this method has made some progress, there are two main unfavorable factors in this technical route: one is the need to consume hydrogen, and the cost of hydrogen is high; the other is that this method cannot effectively reduce the acidity of bio-oil.

Contents of the invention

The invention aims to solve the deficiencies in the prior art, and provides a catalyst for deoxidation and acid reduction in the biomass cracking process, and improves the quality of bio-oil through catalytic upgrading.

The invention also provides a preparation method of the catalyst.

The present invention solves technical problem and adopts following scheme:

The catalyst of the present invention includes a catalyst active component and a catalyst carrier. In terms of mass percentage, the composition of the catalyst active component and the catalyst carrier is: NiO 10-32wt%, MoO ₃ 5-18wt%, CoO 5-15wt%, the remainder as a catalyst carrier.

A group of preferred ratios of the weight percentages of the catalyst components of the present invention are: NiO 20wt%; MoO3 10wt%; CoO15wt%; the remainder is catalyst carrier.

The catalyst carrier is preferably dolomite, and the purity of the dolomite is 99.5% of natural dolomite.

Catalyst preparation method of the present invention, comprises the following steps

(1) Dissolve the soluble salts of nickel, molybdenum and cobalt in water together, the total concentration of the soluble salts is 0.05-1.5mol/l, then add dolomite powder while heating, stir and impregnate at 60°C for 6 hours to form an emulsion;

(2) to the emulsion of step (1), add magnesium nitrate, cetyltrimethylammonium bromide simultaneously, magnesium nitrate is as reinforcing agent, strengthens cohesiveness, and the content of magnesium nitrate accounts for 5% of total emulsion weight -10wt%, cetyltrimethylammonium bromide is used as a surfactant template compound to increase the dispersion of the active surface and active components, and the content accounts for 0.1-1.0wt% of the total emulsion weight, and then add alkaline Precipitating agent, adjust the pH value to 8-12, after precipitation, washing, filtration, drying, molding and roasting, the catalyst Ni-Mo-Co-dolomite can be obtained;

The nickel salt consumption is 10-32wt% of the catalyst Ni-Mo-Co-dolomite by the weight of nickel oxide, and the molybdenum salt consumption is 5% by weight of the catalyst Ni-Mo-Co-dolomite by the weight of molybdenum oxide. -18wt%, the cobalt salt consumption is the CoO 5-15wt% of catalyst Ni-Mo-Co-dolomite by the weight of cobalt oxide.

The nickel, molybdenum and cobalt soluble salts described in the catalyst preparation method of the present invention are preferably selected from the following compounds: nickel nitrate, ammonium molybdate, cobalt nitrate, and the alkaline precipitant is selected from ammonia water.

In the catalyst preparation method of the present invention, the calcination time is 2 to 6 hours, and the calcination temperature is 600°C to 900°C.

Compared with the prior art, the beneficial effects of the present invention are reflected in:

The invention provides a catalyst for deoxygenation and upgrading of bio-oil in the process of preparing high-quality liquid fuel by catalytic cracking conversion of biomass. Bio-oil, improving the economic and technical performance of biomass conversion into clean energy. The dolomite used in the catalyst carrier is cheap and easy to obtain, reducing the production cost. Magnesium nitrate is added to the catalyst to enhance the binding force, cetyltrimethylammonium bromide increases the active surface and the dispersion of active components, and molybdenum, nickel, and cobalt metals are used as catalyst active components, which effectively improves the catalytic performance.

The technical solutions of the present invention will be further described below through examples.

Detailed ways

1. Raw material preparation

Dolomite is calcined at 900°C for 4-6 hours, then crushed to below 120 mesh, and a certain amount of soluble salts of nickel, molybdenum and cobalt are dissolved in deionized water respectively, and the total concentration of soluble salts is 0.05-1.5mol/ l; then add dolomite powder while heating, stir and impregnate at 60°C for 6 hours to form an emulsion.

2. Co-precipitation

The emulsion obtained above is added to magnesium nitrate and cetyltrimethylammonium bromide at the same time, and magnesium nitrate is used as a reinforcing agent to enhance cohesiveness. The content of magnesium nitrate accounts for 5-10wt% of the total emulsion weight , cetyltrimethylammonium bromide is used as surfactant template compound, to increase active surface and active component dispersity, content accounts for 0.1-1.0wt% of total emulsion weight; Nickel salt consumption in soluble salt is The weight of nickel oxide is 10-32wt% of the catalyst Ni-Mo-Co-dolomite, the molybdenum salt consumption is 5-18wt% of the catalyst Ni-Mo-Co-dolomite by the weight of molybdenum oxide, and the cobalt salt consumption is The weight of cobalt oxide is 5-15wt% of CoO of catalyst Ni-Mo-Co-dolomite. Then add alkaline precipitant ammonia water to the above solution, the ammonia water concentration is 15% or 20% ammonia, follow the pH value change with a pH meter, add ammonia water while precipitating to make the pH value 8～12, precipitate and separate out, let stand for 6 Hours, precipitation aging.

3. Molding and calcination

The filter cake obtained after suction filtration is washed with water and dried, and the filter cake is pressed to 10MP with a catalyst former. After the catalyst is formed, the particle size is about 2-4mm, and then roasted for 4 to 6 hours at a roasting temperature of 600°C to 900°C. The weight percentages of each catalytic active component and carrier are respectively: 10-32wt% of NiO; 5-18wt% of MoO3; 5-15wt% of CoO; and the remaining dolomite catalyst carrier.

Prepare following three component catalysts through above-mentioned steps:

Group A: NiO 10wt%; MoO3 18wt%; CoO 5wt%, the rest is dolomite carrier.

Group B: NiO 32wt%; MoO3 5wt%; CoO 15wt%; the rest dolomite carrier.

Group C: NiO is 20wt%; MoO3 is 10wt%; CoO is 15wt%; the rest is catalyst carrier.

Example 1

Tobacco rods are used as raw materials, which are crushed to a particle size of less than 1mm, cracked in a cracking furnace, and the cracking catalytic time is 10 minutes. The liquid product obtained without the action of a catalyst contains 11.47% of acetic acid, 12.52% of butyric acid, ring Hexanone is 7.32%, the nicotine content is 37.42%, the yield of liquid product is 42.30%, and the water content is 40.8%; When adopting the catalyst of Group A prepared above to carry out catalytic reforming to bio-oil vapor, the cracking catalytic time is 10 minutes, Liquid product was collected. Under the action of the catalyst, the liquid product does not contain acid compounds, and the yield of the liquid product is 42.88%, containing 35.6% of furan, 6.04% of butylamine, 7.19% of octyne, 12.75% of heptane, 20.18% of nicotine, and 20.18% of water content. 48.2%.

Example 2

Using wheat stalks as raw materials, the catalyst of group B was selected, and the same steps as in Example 1 were adopted to collect the liquid product. Phenols are the main components of bio-oil without catalyst, except for p-methoxyphenol (13.15%), phenol (10.51%), dimethoxyphenol (9.97%), methylmethoxyphenol (5.04%) , ethyl methoxyphenol (3.79%), cyclopentenone (8.48%), furfural (7.68%), etc. accounted for about 30%; under the action of the catalyst, the main components of bio-oil are furfural and furan. The sum of the concentration is 74.42%. In addition, there are hydrocarbons, such as nonyne, dimethylcyclohexene (2.76%), and decane (1.96%), which account for about 15%.

Example 3

Using Chinese fir as raw material, select group C catalyst for use, adopt the same steps as in Example 1, collect the liquid product, the main components in the bio-oil without catalyst are furfural (22.57%), cyclopentenone (0.22%), 2-methanone Oxyphenol (21.76%), levoglucosan (8.45%), and hydroxybutyric acid (11.64%); under the action of the catalyst, the main components of the bio-oil are furfural and methylfurfural. The sum of the relative concentrations of the two substances reaches 83.38%, There are also alkanes octadecane (2.19%) and cyclopentenone (4.15%).

Claims (4)

1. bio oil deoxidation upgrading method for preparing catalyst is characterized in that, may further comprise the steps:

(1) soluble-salt with nickel, molybdenum and cobalt is dissolved in the water together, and the total concentration of soluble-salt is 0.05-1.5mol/l, and the limit heating edge adds the dolomite powder then, and 60 ℃ of constant temperature stir and flood into emulsion;

(2) to the emulsion of step (1), add magnesium nitrate, softex kw simultaneously, magnesium nitrate is as reinforcing agent; Strengthen caking property, the content of magnesium nitrate accounts for the 5-10wt% of total emulsion weight, and softex kw is as the surfactant templates compound; To increase active surface and active component decentralization; Content accounts for the 0.1-1.0wt% of total emulsion weight, adds alkaline precipitating agent then, regulates pH value to 8～12; Through deposition, washing, filtration, drying, moulding, roasting, promptly get catalyst n i-Mo-Co-dolomite;

Said nickel salt consumption is counted the 10-32wt% of catalyst n i-Mo-Co-dolomite with the weight of nickel oxide; Said molybdenum salt consumption is counted the 5-18wt% of catalyst n i-Mo-Co-dolomite with the weight of molybdenum oxide, and said cobalt salt consumption is counted the CoO 5-15wt% of catalyst n i-Mo-Co-dolomite with the weight of cobalt oxide.

2. bio oil deoxidation upgrading method for preparing catalyst according to claim 1, it is characterized in that: the soluble-salt of said nickel, molybdenum and cobalt is respectively: nickel nitrate, ammonium molybdate, cobalt nitrate.

3. bio oil deoxidation upgrading method for preparing catalyst according to claim 1, it is characterized in that: said alkaline precipitating agent is selected from ammoniacal liquor.

4. bio oil deoxidation upgrading method for preparing catalyst according to claim 1, it is characterized in that: said roasting time is 2～6 hours, sintering temperature is 600 ℃～900 ℃.