阅读说明：本技术 一种生物秸秆制备合成气的方法 (Method for preparing synthesis gas from biological straws ) 是由 朱冬祥 于 2020-07-24 设计创作，主要内容包括：一种生物秸秆制备合成气的方法,包括以下步骤：(1)生物秸秆预处理；(2)碳化；(3)气化；(4)净化；和(5)纯化。本发明公开的方法,在碳化过程中通入空气可使得生物秸秆中的S元素形成SO<Sub>2</Sub>,而加入氧化钙可在高温的条件中与O<Sub>2</Sub>和SO<Sub>2</Sub>反应生成硫酸钙,在气化之前直接去除了气化过程中形成的杂质；在净化过程中去除气化过程所产生的二氧化碳,也能够沉降气体中所带的灰分,起到除杂的作用,提高产物合成气的纯度。本发明使用生物秸秆为原料,原料来源广泛易得,并且所制备的合成气纯度高、用途广泛,是重要的基础化工原料,进一步扩展了生物质的用途和价值。(A method for preparing synthesis gas by biological straws comprises the following steps: (1) pretreating biological straws; (2) carbonizing; (3) gasifying; (4) purifying; and (5) purifying. The method disclosed by the invention can lead the S element in the biological straw to form SO by introducing air in the carbonization process 2 And the calcium oxide can be added to react with O under the condition of high temperature 2 And SO 2 Reaction to produce sulfuric acidCalcium, which directly removes impurities formed during gasification before gasification; the carbon dioxide generated in the gasification process is removed in the purification process, ash in the gas can be settled, the impurity removal effect is achieved, and the purity of the product synthetic gas is improved. The invention uses biological straw as raw material, the raw material source is wide and easy to obtain, and the prepared synthesis gas has high purity and wide application, is an important basic chemical raw material, and further expands the application and value of biomass.)

1. A method for preparing synthesis gas by biological straws is characterized by comprising the following steps:

(1) pretreatment of biological straws: cleaning biological straws, putting the cleaned biological straws into an acid tank for soaking and degrading, taking out the biological straws, leaching with water, drying in the air, and crushing to 100-mesh and 200-mesh;

(2) carbonizing: adding the crushed biological straws into a gasification furnace, then adding calcium oxide with the mass of 0.2 time that of the biological straws, stirring to uniformly mix the biological straws, introducing mixed gas of nitrogen and air, controlling the temperature at 200 ℃ and 300 ℃, and carbonizing; wherein the ratio of the nitrogen to the air at the rate of gas flow is 100: 1;

(3) and (3) gasification: conveying the carbonized biological straws to a gasification furnace, heating the gasification furnace to 1000-1500 ℃, introducing water vapor and 0.02bar of oxygen, and reacting to obtain synthesis gas;

(4) purifying: purifying the synthesis gas obtained in the step (3) by spraying a solution in a purifying chamber to obtain relatively pure synthesis gas;

(5) and (3) purification: further purifying the synthesis gas obtained in the step (4) by a drying agent in a drying chamber to obtain CO and H₂Synthesis gas with a total content of up to 95%.

2. The method for preparing the synthesis gas by the biological straws as claimed in claim 1, which is characterized in that: in the step (1), the biological straws comprise one or more of corn straws, wheat straws, rape straws, rice straws and sugarcane straws; the acid pool is a dilute sulphuric acid solution.

3. The method for preparing the synthesis gas by the biological straws as claimed in claim 1, which is characterized in that: in the step (2), the nitrogen flow rate is 500-700 mL/min.

4. The method for preparing the synthesis gas by the biological straws as claimed in claim 1, which is characterized in that: in the step (3), the pressure of the water vapor in the furnace is kept at 0.1-0.2 MPa.

5. The method for preparing the synthesis gas by the biological straws as claimed in claim 1, which is characterized in that: in the step (4), the spraying solution in the purifying chamber is sodium carbonate or potassium carbonate saturated solution.

6. The method for preparing the synthesis gas by the biological straws as claimed in claim 1, which is characterized in that: in the step (5), the drying agent is one of soda lime, quicklime and anhydrous calcium chloride.

Technical Field

The invention belongs to a preparation method of synthesis gas, and particularly relates to a method for preparing synthesis gas from biological straws.

Background

As the demand for fossil resources and chemicals we rely heavily on increases, two important challenges now face the world: a decrease in fuel supply and a great increase in greenhouse gas emissions. The conversion of biomass resources into fuels and chemicals can become an important component for solving the energy crisis and low carbon emission. As a renewable energy source with abundant reserves, the biomass mainly comprises carbon, hydrogen and oxygen elements, and has negligible sulfur, nitrogen and ash content and wide research value. With the continuous research and exploration of biomass resources. At present, the conversion, utilization and research on biomass resources are mainly focused on the following four fields, mainly including a biological conversion technology (anaerobic fermentation), a direct combustion technology (biomass combustion power generation), a biomass supercritical fluid conversion technology, a biomass thermochemical conversion technology (biomass pyrolysis, thermal gasification) and the like. However, the existing biomass thermochemical conversion technology is a technology for forming a new biomass energy source by utilizing different composition structures and chemical properties of biomass components, namely lignin, cellulose and hemicellulose and changing the characteristics of the biomass components, and few researches are made on the preparation of synthesis gas by utilizing biomass.

The synthesis gas is mainly prepared by a natural gas steam conversion method, a light oil steam conversion method, a natural gas partial oxidation method, a heavy oil partial oxidation method, a novel coal chemical industry and the like, and the research on preparing the synthesis gas by using biomass is still popular. However, the method is very easy to generate a large amount of pollutants such as hydrogen sulfide, coal tar, phenol water and the like in the production process, and has great damage to the environment and human bodies.

Disclosure of Invention

Aiming at the technical problems, the invention aims to provide a method for preparing water gas by using biological straws.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a method for preparing synthesis gas by biological straws comprises the following steps:

(1) pretreatment of biological straws: cleaning biological straws, putting the cleaned biological straws into an acid tank for soaking and degrading to enable elements such as magnesium, potassium and calcium in the biological straws to form soluble salts for dissolving, taking out the biological straws, leaching with water, drying in the air and crushing;

(2) carbonizing: adding the crushed biological straws into a gasification furnace, then adding calcium oxide with the mass of 0.2 time that of the biological straws, stirring to uniformly mix the biological straws, introducing mixed gas of nitrogen and air, controlling the temperature at 200 ℃ and 300 ℃, and carbonizing; wherein the ratio of the nitrogen to the air at the rate of gas flow is 100: 1;

(3) and (3) gasification: after carbonization, heating the gasification furnace to 1000-1500 ℃, and introducing water vapor and 0.02bar of oxygen to obtain crude synthesis gas and residual solids;

(4) purifying: purifying the synthesis gas obtained in the step (3) by spraying a solution in a purifying chamber to obtain relatively pure synthesis gas;

(5) and (3) purification: further purifying the water gas obtained in the step (4) by a drying agent in a drying chamber to obtain CO and H₂The total content of synthesis gas is 95%.

Preferably, in the step (1), the biological straws comprise one or more of corn straws, wheat straws, rape straws, rice straws and sugarcane straws; the acid pool is a dilute sulphuric acid solution.

Preferably, in the step (1), the biological straws are crushed to 100-200 meshes.

Preferably, in the step (2), the nitrogen gas rate is 500-700 mL/min.

Preferably, in the step (3), the pressure of the water vapor in the furnace is kept at 0.1-0.2 MPa.

Preferably, in the step (4), the spraying solution in the purification chamber is sodium carbonate or potassium carbonate saturated solution.

Preferably, in the step (5), the drying agent comprises one of soda lime, quicklime and anhydrous calcium chloride.

The carbonization process causes the straws to lose moisture and other easily decomposed substances to form coke, which is beneficial to the preparation of synthesis gas; the S element in the biological straw can form SO by introducing air₂The added calcium oxide can react with O under the condition of high temperature₂And SO₂The reaction produces calcium sulfate, and impurities formed during gasification are directly removed before gasification.

The main reactions that occur in the gasification process are as follows: h₂O(g)+C(s)→CO(g)+H₂(g)；

Side reaction: c(s) + O₂(g)→CO₂(g)；CO₂(g)+C(s)→CO(g)

The introduced oxygen is beneficial to the gasification process, and the gasification time is effectively shortened; and residual solids obtained in the gasification process can be used for modifying acid soil.

By spraying sodium carbonate or potassium carbonate and other solutions, carbon dioxide generated in the gasification process can be effectively removed, ash in the gas can be settled, and the effect of removing impurities is achieved.

The invention has the following beneficial effects:

the invention uses biological straw as raw material to prepare synthesis gas. The raw materials are widely and easily available, and the prepared synthesis gas has wide application, is a basic chemical raw material, and further expands the application of the biomass. The method for preparing the synthesis gas by using the biological straws can effectively remove sulfur dioxide and other toxic gases, and is simple in operation process.

Detailed Description