CN1375355A

CN1375355A - Regenerable metal oxide desulfurizer and its prepn. process

Info

Publication number: CN1375355A
Application number: CN 01133520
Authority: CN
Inventors: 向军; 孙学信
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-09-30
Filing date: 2001-09-30
Publication date: 2002-10-23

Abstract

The desulfurizing agent is made from metal oxide (oxide of copper, zinc, iron, sodium, nickel and titanium, etc.) as main component, and can be divided into two types of DSO1 and DSO2. The preparation method of DSO1 includes the following steps: firstly, preparing carrier using Al2O3, ZnO, NiO, TiO2 and Na2O as component, the attaching the metal oxide to the carrier, and the preparation method of DSO2 includes the following steps: mixing the metal oxide, activating agent, adhesive and pore-forming agent and making them undergo the one-step forming process to obtain the invented product. It can be used for desulfurizing and cleaning fuel gas and flue gas, and its desulfurizing efficiency can be up to 90%.

Description

Regenerable metal oxide desulfurizing agent and preparation process thereof

Technical Field

The invention relates to a method for removing SO in flue gas₂Re-generation of gasA raw metal oxide desulfurizer and a preparation process thereof.

Background

SO contained in flue gas (gas) released by burning fossil fuel (coal, petroleum, natural gas and the like) in industries of energy, chemical industry, metallurgy, electronics and the like₂Causes serious pollution to the atmosphere, and currently China becomes the SO in the world₂The environmental problem becomes a key problem of whether national economy of China can be continuously developed or not when the first and third large acid rain areas are discharged. In recent years, the governments in China pay great attention to environmental problems, for example, the environmental protection law in China is clearly stipulated, and a power station boiler burning coal with the sulfur content of more than 1% needs to be provided with a desulfurization facility.

Practical experience of countries in the world in recent years shows that the flue gas purification technology is SO control of coal-fired power plants₂An efficient way of discharging. Conventional control of SO₂The discharging method mainly comprises wet flue gas desulfurization, rotary spray dry desulfurization, in-furnace calcium spraying desulfurization and the like, most of the used desulfurizing agents are quicklime and limestone, and the methods are successfully applied, such as a control method of a flue gas wet method and a desulfurization process (patent number 87102943), a flue gas desulfurization method (patent number 87106325) and the like, but have the problems of high desulfurization cost, difficulty in recycling desulfurization byproducts, secondary pollution and the like due to landfill, and in addition, a large amount of waste water is generated by adopting a wet desulfurization technology to cause water pollution. Based on this, it is urgent to research and develop a renewable metal oxide desulfurizer with low cost, high efficiency and no secondary pollution and a preparation process thereof.

Many documents show that the dry-process metal oxide desulfurizer is a promising flue gas purification technology, and in recent years, many works have been done on the aspects of selection and preparation of absorbents and catalysts and desulfurization performance mechanisms in many scientific research institutes in the U.S. and the uk, for example, in 1970, the SHELL company in the U.S. develops and designs a set of fixed bed metal oxide desulfurization reactors, and proposes a composite metal oxide desulfurizer which is used for desulfurizing flue gas to achieve 90% of desulfurization efficiency.

Disclosure of Invention

The invention aims to provide a desulfurizing agent which has the advantages of high desulfurizing reaction speed, desulfurizing efficiency of over 90 percent, low cost and high cost performance, and can be regenerated and recycled; the metal oxide desulfurizer and the preparation process thereof have the advantages that the water solution is not used, the desulfurization byproducts can be completely recycled, and the liquid and solid secondary pollution is avoided, thereby meeting the requirements of industrial application.

The invention aims to realize the regenerable metal oxide desulfurizer and the preparation process thereof, wherein the regenerable metal oxide desulfurizer comprises two desulfurizers which are named as a DS01 type desulfurizer and a DS02 type desulfurizer respectively.

The DS01 type is a metal oxide (the main component is copper oxide) desulfurizer attached to a carrier, and the preparation process comprises the following steps:

the preparation process comprises three steps: first, select 85-95% gamma-Al₂O₃Adding 2-8% of ZnO and 2-7% of NiO and TiO into the powder₂Mixing, adding water, stirring to obtain paste, shaping to obtain cylinder, sphere or Raschig ring, drying at 105 deg.C for 3-5 hr, calcining at 850 deg.C for 1-5 hr, activating to obtain carrier, and immersing the carrier in saturated CuSO₄Soaking in water solution for 1-2 hr, drying in oven at 230 deg.C for 1 hr, taking out the carrier, and soaking in saturated CuSO₄Soaking in water solution, drying in oven for 2-5 times to obtain intermediate carrier, and calcining the intermediate carrier in constant-temperature oven at 450-850 deg.C for 1-5 hr to obtain CuSO attached to the carrier₄Converted into CuO, and finally the DS01 type desulfurizing agent is prepared.

Physical parameters of the support: the specific surface of the carrier is 10-200m²(ii)/g, bulk density of about 0.7g/ml, abrasion rate of less than 0.4%, point crushing strength of more than 100N/piece, cylindrical shape of phi (6 x 24) mm x (6-24) mm cylinder,the ball shape is a sphere with phi (6 multiplied by 24) mm, the Raschig ring shape is a Raschig ring with phi (6-24) mmx (6-24) mm and the thickness of (2-16) mm.

The DS02 type desulfurizer is a desulfurizer formed by mixing metal oxide, an activator and an additive and formed in one step, and the preparation process comprises the following steps:

70-90 wt% of CuO, 5-15 wt% of alumina activator, 5-15 wt% of diatomite adhesive and 1-5 wt% of wood chip pore-forming agent are mixed and fed into a stirring/bonding machine, water is added to fully stir into paste, the paste is placed into a forming machine to form a cylinder, a sphere or a Raschig ring body, then the cylinder, the sphere or the Raschig ring body is dried in an oven at 105 ℃ for 3-5 hours and is roasted at 450-850 ℃ for 1-5 hours, and the DS02 type desulfurizer is prepared by activation.

Physical parameters of the desulfurizing agent: the specific surface area of the desulfurizing agent is 10-150m²The ball-shaped ring is a sphere with phi (6 multiplied by 24) mm multiplied by (6 multiplied by 24) mm, and the Raschig ring is a Raschig ring with phi (6 multiplied by 24) mm multiplied by (6 multiplied by 24) mm and the thickness of (2-16) mm.

The method takes metal oxide as a main absorbent, and removes SO in the flue gas at the reaction temperature of 300-450 ℃ and the retention time of 0.5-2.5s₂The reaction is as follows: wherein MO represents a metal oxide.

The invention adopts the technology and equipment of renewable metal oxide desulfurization technology and system simultaneously applied by the applicant, SO that a large amount of SO is adsorbed in the reactor₂The desulfurizer is transferred to a regeneration system by a transmission mechanism for regeneration, and the following regeneration reaction is carried out at the temperature of 450-800 ℃: 。

the regenerated desulfurizer is transferred to a desulfurization reactor by a transmission mechanism to participate in desulfurization. SO generated during regeneration₂、SO₃The mixed gas is sent to a by-product treatment part and is subjected to catalytic conversion and absorption to obtain a concentrated sulfuric acid by-product with the concentration of more than 92%.

The two desulfurizing agents are used for carrying out laboratory small-sized heating furnace simulated flue gas experiments and laboratory pulverized coal furnace thermal state experiments, and experimental results show that the desulfurizing agent is an efficient and economic desulfurizing agent. The desulfurizer has the following characteristics:

(1) the raw materials are easy to purchase, the desulfurizer is easy to prepare, the cost is low, and the cost performance is high;

(2) the desulfurizer has high activity and high sulfur capacity;

(3) the specific surface area is large, the contact surface with the flue gas is large, and the desulfurization reaction speed is high;

(4) the desulfurizer has good stability and wear resistance, the catalyst keeps certain activity and is not poisoned;

(5) the desulfurization efficiency is high, and the simulated flue gas experiment reaches over 90 percent of desulfurization efficiency;

(6) the desulfurizer can be regenerated after being saturated, can be recycled, hardly loses, and further reduces the desulfurization operation cost;

(7) compared with the conventional calcium-based desulfurization method, the desulfurizer is in a dry state, does not use aqueous solution, and simultaneously, desulfurization byproducts can be completely recycled, so that no liquid or solid secondary pollution is caused.

Detailed Description

Examples of the invention are given below:

desulfurizing agent type DS 01: selecting 88% gamma-Al₂O₃Powder, adding 5 percent of ZnO and 5 percent of catalyst NiO and TiO₂The balance of Na₂O, FeO, feeding into a bonder, adding water, stirring thoroughly to paste, molding in a molding machine, drying in an oven at 105 deg.C for 4 hr, calcining at 650 deg.C, activating to obtain Raschig ring carrier with external dimensions: the external diameter is 18mm, the internal diameter is 4mm, the length is 18mm, the bulk density is about 0.7g/ml, the abrasion rate is less than 0.4 percent, and the point crushing strength is more than 100N/particle. Putting the prepared catalytic carrier into saturated CuSO₄Soaking in water solution for 1-2 hr, drying in oven at 230 deg.C for 1 hr, taking out the carrier, and placing in saturated CuSO₄Soaking in the water solution, drying again,repeating the above steps for 4 times to obtainObtaining the intermediate carrier. Then, the intermediate carrier is put into a constant temperature furnace body of 650 ℃ and air is introduced for roasting for 2 hours, and CuSO attached to the carrier is obtained₄Converted into CuO, and finally the DS01 type Raschig ring desulfurizing agent is prepared.

Likewise, 90% gamma-Al is beneficiated₂O₃Powder, adding 4 percent of ZnO and 4 percent of catalyst NiO and TiO₂And 2% of Na₂O, FeO, preparing DS01 type cylindrical desulfurizer with phi 16mm multiplied by 16mm and spherical desulfurizer with phi 16mm according to the method.

Desulfurizing agent type DS 02: mixing 80% of CuO main active component, 12% of alumina activator, 5% of diatomite adhesive and 3% of sawdust pore-forming agent, feeding the mixture into a bonding machine, adding a proper amount of water, fully stirring the mixture into paste, then placing the paste into a forming machine for forming, then placing the paste into an oven for drying for 4 hours at 105 ℃, roasting and activating the paste at 650 ℃ to prepare Raschig ring DS02 type desulfurizer with the external dimension of: the outer diameter is 14mm, the inner diameter is 3mm, and the length is 14 mm. The bulk density is about 0.8g/ml, the abrasion rate is less than 0.4 percent, and the mechanical strength is more than 80N/cm²。

Similarly, 84% of CuO main active component, 8% of alumina activator, 5% of diatomite binder and 3% of sawdust pore-forming agent are mixed to prepare DS02 type cylindrical desulfurizer with phi 16mm multiplied by 16mm and spherical desulfurizer with phi 16mm according to the method.

The two desulfurizing agents are used for carrying out a laboratory small-sized heating furnace flue gas simulation experiment, and the technology and equipment of 'renewable metal oxide desulfurization technology and system' simultaneously applied by the applicant are adopted, wherein the simulated flue gas comprises the following components in volume ratio: 6% of oxygen, 5% of water vapor, 2000ppm, 1500ppm and 1000ppm of sulfur dioxide, and the balance of nitrogen. The components of the flue Gas before and after desulfurization were measured by a flue Gas Analyzer (Master2000 Gas Analyzer) and a chemical titration method. The desulfurization reactor and the regeneration reactor both adopt electric heating tube furnaces to maintain stable reaction temperature. The experimental results show that:

(1) at 2000ppm, 1500ppm and 1000ppm of three inlet SO₂Under the gas concentration, the desulfurization-regeneration experiments of 12 periods are respectively carried out, and the desulfurization rate can still be maintained to be more than 88 percent;

(2) inlet SO₂Gas concentrationWhen the degree is 1500ppm, the desulfurization efficiency is superior to other working conditions, and the desulfurization efficiency can reach 92% in most of time;

(3) the specific surface measurement shows that the specific surface of the desulphurized agent is reduced by about 8-10% compared with that of a fresh desulphurized agent, and after regeneration, the specific surface is basically recovered;

(4) the regenerated absorbent can maintain good activity and long service life;

(5) SO in regenerated gas₂The concentration of the catalyst can reach 6 percent (volume ratio), so that the by-product can be conveniently treated and utilized, and secondary pollution is avoided;

(6) the desulfurizer can meet the requirements of industrial application.

Claims

1. A regenerable metal oxide desulfurizer and a preparation process thereof, wherein the DS01 type is a metal oxide desulfurizer (mainly comprising copper oxide) attached to a carrier, and the preparation process is characterized in that:

the preparation process of the DS01 type desulfurizing agent comprises three steps: first, select 85-95% gamma-Al₂O₃Adding 2-8% of ZnO and 2-7% of NiO and TiO into the powder₂Mixing, adding water, stirring to obtain paste, shaping to obtain cylinder, sphere or Raschig ring, drying at 105 deg.C for 3-5 hr, calcining at 850 deg.C for 1-5 hr, activating to obtain carrier, and immersing the carrier in saturated CuSO₄Soaking in water solution for 1-2 hr, drying in oven at 230 deg.C for 1 hr, taking out the carrier, and soaking in saturated CuSO₄Soaking in water solution, drying in oven for 2-5 times to obtain intermediate carrier, and calcining the intermediate carrier in constant-temperature oven at 450-850 deg.C for 1-5 hr to obtain CuSO attachedto the carrier₄Converted into CuO, and finally the DS01 type desulfurizing agent is prepared.

2. The desulfurizing agent and the process for preparing the same according to claim 1, wherein the carrier is a substance of a carrierPhysical parameters: the specific surface of the carrier is 10-200m²The grain size is 0.7g/ml, the abrasion rate is less than 0.4 percent, the point crushing strength is more than 100N per grain, the cylindrical shape is a cylinder with phi (6 multiplied by 24) mm multiplied by (6-24) mm, the spherical shape is a sphere with phi (6 multiplied by 24) mm, and the Raschig ring shape is a Raschig ring with phi (6-24) mm multiplied by (6-24) mm and the thickness is 2-16 mm.

3. A regenerable metal oxide desulfurizer and a preparation process thereof, wherein the DS02 type desulfurizer is a desulfurizer formed by mixing metal oxide, an activator and an additive and formed in one step, and is characterized in that the preparation process comprises the following steps: 70-90 wt% of CuO, 5-15 wt% of alumina activator, 5-15 wt% of diatomite adhesive and 1-5 wt% of wood chip pore-forming agent are mixed and fed into a stirring/bonding machine, water is added to fully stir into paste, the paste is placed into a forming machine to form a cylinder, a sphere or a Raschig ring body, then the cylinder, the sphere or the Raschig ring body is dried in an oven at 105 ℃ for 3-5 hours and is roasted at 450-850 ℃ for 1-5 hours, and the DS02 type desulfurizer is prepared by activation.

4. The desulfurizing agent and the process for preparing the same according to claim 3, characterized in that the physical parameters of the desulfurizing agent are as follows: the specific surface area of the desulfurizing agent is 10-150m²The ball-shapedring is a sphere with phi (6 multiplied by 24) mm multiplied by (6 multiplied by 24) mm, and the Raschig ring is a Raschig ring with phi (6 multiplied by 24) mm multiplied by (6 multiplied by 24) mm and the thickness of (2-16) mm.