阅读说明：本技术 一种脱除生物质中氯离子和碱金属离子的方法 (Method for removing chloride ions and alkali metal ions in biomass ) 是由 黎福斌 杨勇 李亚洲 李健 万鹏 孙健 祁文 于 2020-12-08 设计创作，主要内容包括：本发明涉及秸秆等农业固体废弃物生物质能源化利用技术领域,特别是涉及一种脱除生物质氯离子和碱金属离子的方法。该方法包括如下步骤：1)将生物质进行破碎处理；2)将步骤1)得到的生物质在浸泡水洗溶液中进行浸泡水洗处理,其中,所述浸泡水洗溶液包括水,以及酸性添加剂或碱性添加剂；3)将步骤2)得到的生物质进行机械脱水处理。本发明在包括酸性添加剂或碱性添加剂的浸泡水洗溶液中进行浸泡水洗处理,促进生物质内部的无机盐析出,提高生物质中氯离子和碱金属离子等无机盐脱除率和处理效率,改善生物质燃料的燃烧特性。(The invention relates to the technical field of energy utilization of agricultural solid waste biomass such as straws and the like, in particular to a method for removing biomass chloride ions and alkali metal ions. The method comprises the following steps: 1) crushing the biomass; 2) soaking and washing the biomass obtained in the step 1) in a soaking and washing solution, wherein the soaking and washing solution comprises water and an acidic additive or an alkaline additive; 3) mechanically dehydrating the biomass obtained in the step 2). The method carries out soaking and washing treatment in the soaking and washing solution containing the acidic additive or the alkaline additive, promotes the precipitation of inorganic salts in the biomass, improves the removal rate and treatment efficiency of inorganic salts such as chloride ions, alkali metal ions and the like in the biomass, and improves the combustion characteristic of the biomass fuel.)

1. A method for removing chloride ions and alkali metal ions from biomass is characterized by comprising the following steps:

1) crushing the biomass;

2) soaking and washing the biomass obtained in the step 1) in a soaking and washing solution, wherein the soaking and washing solution comprises water and an acidic additive or an alkaline additive;

3) mechanically dehydrating the biomass obtained in the step 2).

2. The method for removing chloride ions and alkali metal ions from biomass according to claim 1, wherein the step 1) further comprises at least one of the following technical features:

11) the length of the biomass subjected to crushing treatment is less than or equal to 20cm, and the diameter of the biomass is less than or equal to 2 cm;

12) and carrying out screening separation treatment after crushing treatment.

3. The method for removing chloride ions and alkali metal ions from biomass according to claim 1, wherein the step 2) further comprises at least one of the following technical features:

21) the soaking water washing solution is a liquid solution under the pressure of 0 bar-1 bar;

22) the mass ratio of the soaking water washing solution to the biomass after the crushing treatment is more than or equal to 2: 1;

23) the soaking and water washing treatment time is more than or equal to 5 minutes;

24) the temperature of the soaking and washing solution is 0-95 ℃.

4. The method for removing chloride and alkali metal ions from biomass according to claim 3, further comprising at least one of the following technical features:

221) the characteristic 22) is that the mass ratio of the soaking water washing solution to the biomass after the crushing treatment is 3: 1-15: 1;

231) characteristic 23), the soaking and water washing treatment time is 10 to 30 minutes.

5. The method for removing chloride and alkali metal ions from biomass according to claim 1, wherein in step 2), the acidic additive is at least one selected from oxalic acid, citric acid and sulfuric acid.

6. The method for removing chloride and alkali metal ions from biomass according to claim 5, wherein the concentration of the acidic additive is 0.1mol/L to 3.0 mol/L.

7. The method for removing chloride and alkali metal ions from biomass according to claim 1, wherein in step 2), the alkaline additive is at least one selected from urea and sodium hydroxide.

8. The method for removing chloride and alkali metal ions from biomass according to claim 7, wherein the concentration of the alkaline additive is 0.1mol/L to 1.6 mol/L.

9. The method for removing chloride ions and alkali metal ions from biomass according to claim 1, wherein the drying treatment is performed after the mechanical dehydration treatment in the step 3).

10. The method for removing chloride and alkali metal ions from biomass according to claim 9, further comprising at least one of the following technical features:

31) mechanically dehydrating until the mass percent of water in the biomass is less than or equal to 60 percent;

32) the drying temperature is 0-300 ℃.

Technical Field

The invention relates to the technical field of energy utilization of agricultural solid waste biomass such as straws and the like, in particular to a method for removing biomass chloride ions and alkali metal ions.

Background

The Paris protocol requires that the global warming range be controlled to a range below 2 ℃ on a pre-industrial level basis, and the world climate Committee proposes a clear coal reduction usage plan: the coal-electricity machine set with the capacity of 3/4 in the world needs to be shut down within 2 ℃ of the temperature rise of the earth. The installed capacity of coal in China exceeds 10 hundred million kilowatts, and the coal consumption in 2018 is 37 hundred million tons of standard coal. The carbon emission of the total value of the domestic unit production in 2030 years promised in China is reduced by 60-65% compared with that in 2005, the method faces huge pressure and challenge of carbon dioxide emission reduction, and a development road of coal reduction and gradual coal removal is needed to be taken for the challenge of Chinese coal and electricity.

The biomass is an internationally recognized low-carbon clean renewable energy source, and the discharge amount of carbon dioxide in electricity consumption is equal to that of wind power. The straw resources are abundant in China, the cultivated land area of crops is about 18 hundred million mu, the total amount of the straw biomass can be collected by about 9 hundred million tons every year, and all energy utilization can replace 4 hundred million tons of standard coal. The open burning of the straw causes serious dust haze pollution and higher fire risk coefficient, and the state is strictly forbidden. The straw has large volume, light density and high storage and transportation cost, the high content of chloride ions and alkali metal ions in the straw causes coking and slagging of a boiler burner and serious high-temperature chlorine corrosion, and the straw is treated to be a difficult and painful problem for governments and common people.

The straws contain a large amount of alkali metal ions such as potassium and sodium and chloride ions (the content is up to more than 1 percent), the potassium and sodium ions are the main reasons for low ash melting point of the straws after combustion, and when the chlorine content in the fuel is more than 0.3 percent, the high-temperature corrosion tendency is serious. In high temperature corrosion of boiler tubes, corrosion of sulfur is disposable, while corrosion of chlorine is repetitive and not negligible. The existing biomass granular fuel compression molding technology solves the difficult problems of transportation and storage of biomass fuels such as straws and the like, but cannot improve the problems of combustion, coking and slagging.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide a method for removing biomass chloride ions and alkali metal ions, which is used for solving the problems that the coking and slagging heating surface of a boiler is seriously corroded at high temperature and the like due to low ash fusion point of direct combustion of biomass fuels such as straws and the like in the prior art. The method removes chloride ions, alkali metal ions and other components which are not beneficial to combustion in the biomass such as straws by soaking and washing the biomass with the soaking and washing solution, improves the fuel combustion characteristics of the biomass such as the straws, and can be used as fuel to be combusted in various common boiler combustors so as to solve the problems of coking, slagging and corrosion.

In order to achieve the above objects and other related objects, the present invention provides a method for removing chloride ions and alkali metal ions from biomass, comprising the steps of:

1) crushing the biomass;

2) soaking and washing the biomass obtained in the step 1) in a soaking and washing solution, wherein the soaking and washing solution comprises water and an acidic additive or an alkaline additive;

3) mechanically dehydrating the biomass obtained in the step 2).

On the premise of no acid additive or no alkaline additive, the time for soaking and washing the biomass to remove inorganic salt ions is long, and the efficiency is low. The soaking and washing treatment is carried out in the soaking and washing solution containing the acidic additive or the alkaline additive, so that the inorganic salt precipitation in the biomass can be promoted, the ion removal rate and the treatment efficiency are improved, and the combustion characteristic of the biomass fuel is improved.

Preferably, step 1) further comprises at least one of the following technical features:

11) the length of the biomass subjected to crushing treatment is less than or equal to 20cm, and the diameter of the biomass subjected to crushing treatment is less than or equal to 2 cm. More preferably, the biomass after the crushing treatment has a length of 2cm to 5 cm.

12) And carrying out screening separation treatment after crushing treatment. And (4) screening and separating impurities such as silt, stones and the like.

Preferably, step 2) further comprises at least one of the following technical features:

21) the soaking water washing solution is a liquid solution under the pressure of 0 bar-1 bar;

22) the mass ratio of the soaking water washing solution to the biomass after the crushing treatment is more than or equal to 2: 1, as 2: 1-3: 1. 3: 1-10: 1, 10: 1-15: 1, 15: 1-20: 1, etc.; inorganic salt ions in the biomass are removed by soaking and washing in the same solution, the biomass ion removal rate and the liquid-solid ratio are close to a direct proportion relation, and the product ion removal rate is higher when the liquid-solid ratio is higher; however, the larger the liquid-solid ratio, the higher the running cost of the process and the poor economical efficiency. Therefore, the appropriate liquid-solid ratio needs to be determined according to the requirement on the ion content of the product;

23) the soaking and water washing treatment time is more than or equal to 5 minutes, such as 5 minutes to 10 minutes, 10 minutes to 20 minutes, 20 minutes to 30 minutes and the like;

24) the temperature of the soaking and washing solution is 0-95 ℃, such as 0-20 ℃, 20-30 ℃, 30-50 ℃, 50-60 ℃ or 60-95 ℃.

More preferably, at least one of the following technical characteristics is also included:

221) the characteristic 22) is that the mass ratio of the soaking water washing solution to the biomass after the crushing treatment is 3: 1-15: 1;

231) characteristic 23), the soaking and water washing treatment time is 10 to 30 minutes.

Preferably, in step 2), the acidic additive is selected from at least one of oxalic acid, citric acid and sulfuric acid.

More preferably, the concentration of the acidic additive is 0.1 to 3.0mol/L, such as 0.1 to 1mol/L or 1 to 3.0 mol/L.

Preferably, in step 2), the alkaline additive is selected from at least one of urea and sodium hydroxide.

More preferably, the concentration of the basic additive is 0.1 to 1.6mol/L, such as 0.1 to 1.2mol/L or 1.2 to 1.6 mol/L.

Preferably, in step 3), the mechanical dehydration treatment is followed by a drying treatment. After drying, the biomass fuel can be prepared or directly combusted. At lower temperatures, the dryness of the biomass can be increased by evaporating the water by heating, but the ion content cannot be reduced. Because the solubility of chloride ions and potassium ions in water vapor is very low, the chloride ions and potassium ions taken away in the process of water evaporation are very limited, and the ions in the solution after water evaporation are enriched in the biomass product.

More preferably, at least one of the following technical characteristics is also included:

31) mechanical dehydration treatment is carried out until the mass percent of water in the biomass is less than or equal to 60 percent, such as 60-50 percent, 50-30 percent and the like, thus being beneficial to improving the ion removal rate;

32) the drying temperature is 0-300 ℃.

According to the method for removing the chloride ions and the alkali metal ions in the biomass, disclosed by the invention, the additive is added into the water, so that the removal rate of inorganic salts such as the chloride ions and the alkali metal ions in the biomass is improved, and the combustion characteristic of the biomass fuel is improved.

Detailed Description

The technical solution of the present invention is illustrated by specific examples below. It is to be understood that one or more method steps mentioned in the present invention do not exclude the presence of other method steps before or after the combination step or that other method steps may be inserted between the explicitly mentioned steps; it should also be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Moreover, unless otherwise indicated, the numbering of the various method steps is merely a convenient tool for identifying the various method steps, and is not intended to limit the order in which the method steps are arranged or the scope of the invention in which the invention may be practiced, and changes or modifications in the relative relationship may be made without substantially changing the technical content.

Example 1

(1) Crushing and screening straws: crushing a corn straw biomass raw material into a biomass material with the length of 2-5 cm and the diameter of not more than 2 cm;

(2) soaking and washing treatment: soaking the corn straw biomass obtained in the step 1) in 1mol/L oxalic acid aqueous solution, wherein the water temperature of the oxalic acid aqueous solution is 30 ℃, the mass ratio of the oxalic acid aqueous solution to the corn straw biomass obtained in the step 1) is 10:1, and the soaking time is 30 minutes;

(3) mechanical dehydration treatment: reducing the moisture mass content of the biomass obtained in the step 2) to 50% through natural dehydration and mechanical filter pressing dehydration;

(4) the dry chlorine ion content of the biomass raw material is 1.14 percent, and the potassium ion content is 1.6 percent; after the treatment by the method, the content of chloride ions in the dry biomass is 0.143 percent, and the content of potassium ions in the dry biomass is 0.16 percent; the removal rate of chloride ions is 87.5 percent, the removal rate of potassium ions is 90 percent, and the ash melting point is 1365 ℃ (GB/T30726-2014).

Example 2

(1) Crushing and screening straws: crushing a corn straw biomass raw material into a biomass material with the length of 5-10 cm and the diameter of not more than 1 cm;

(2) soaking and washing treatment: soaking the corn straw biomass obtained in the step 1) in a 1.2mol/L sodium hydroxide aqueous solution, wherein the water temperature of the sodium hydroxide aqueous solution is 60 ℃, the mass ratio of the sodium hydroxide aqueous solution to the corn straw biomass obtained in the step 1) is 15:1, and the soaking time is 20 minutes;

(3) mechanical dehydration treatment: reducing the moisture mass content of the biomass obtained in the step 2) to 50% through natural dehydration and mechanical filter pressing dehydration;

(4) the dry chlorine ion content of the biomass raw material is 1.14 percent, and the potassium ion content is 1.6 percent; after the treatment by the method, the content of chloride ions in the dry biomass is 0.075 percent, and the content of potassium ions in the dry biomass is 0.13 percent; the chloride ion removal rate is 93.4 percent, the potassium ion removal rate is 91.9 percent, and the ash melting point is 1380 ℃ (GB/T30726-2014).

Example 3

(1) Crushing and screening straws: crushing a corn straw biomass raw material into a biomass material with the length of 2-5 cm and the diameter of not more than 1 cm;

(2) soaking and washing treatment: soaking the corn straw biomass obtained in the step 1) by using 3mol/L citric acid aqueous solution, wherein the water temperature of the citric acid aqueous solution is 20 ℃, and the mass ratio of the citric acid aqueous solution to the corn straw biomass obtained in the step 1) is 2: 1, soaking for 5 minutes;

(3) mechanical dehydration treatment: reducing the mass content of the water in the biomass obtained in the step 2) to 30% through natural dehydration and mechanical filter pressing dehydration;

(4) the dry chlorine ion content of the biomass raw material is 1.14 percent, and the potassium ion content is 1.6 percent; after the treatment by the method, the content of chloride ions in the dry biomass is 0.759 percent, and the content of potassium ions in the dry biomass is 1.08 percent; the removal rate of chloride ions is 33.4 percent, the removal rate of potassium ions is 32.5 percent, and the ash melting point is 1100 ℃ (GB/T30726-2014).

Example 4

(1) Crushing and screening straws: crushing a corn straw biomass raw material into a biomass material with the length of 2-4 cm and the diameter of not more than 2 cm;

(2) soaking and washing treatment: soaking the corn straw biomass obtained in the step 1) by using 0.1mol/L sulfuric acid aqueous solution, wherein the water temperature of the sulfuric acid aqueous solution is 50 ℃, and the mass ratio of the sulfuric acid aqueous solution to the corn straw biomass obtained in the step 1) is 3: 1, soaking for 30 minutes;

(3) mechanical dehydration treatment: reducing the moisture mass content of the biomass obtained in the step 2) to 50% through natural dehydration and mechanical filter pressing dehydration;

(4) the dry chlorine ion content of the biomass raw material is 1.14 percent, and the potassium ion content is 1.6 percent; after the treatment by the method, the content of chloride ions in the dry biomass is 0.214 percent, and the content of potassium ions in the dry biomass is 0.32 percent; the chloride ion removal rate is 81.2 percent, the potassium ion removal rate is 80 percent, and the ash melting point is 1310 ℃ (GB/T30726-2014).

Example 5

(1) Crushing and screening straws: crushing a corn straw biomass raw material into a biomass material with the length of 5-10 cm and the diameter of not more than 1 cm;

(2) soaking and washing treatment: soaking the corn stalk biomass obtained in the step 1) by using 1.6mol/L of urea aqueous solution, wherein the water temperature of the urea aqueous solution is 5 ℃, and the mass ratio of the urea aqueous solution to the corn stalk biomass obtained in the step 1) is 10:1, soaking for 20 minutes;

(3) mechanical dehydration treatment: reducing the moisture mass content of the biomass obtained in the step 2) to 50% through natural dehydration and mechanical filter pressing dehydration;

(4) the dry chlorine ion content of the biomass raw material is 1.14 percent, and the potassium ion content is 1.6 percent; after the treatment by the method, the content of chloride ions in the dry biomass is 0.13 percent, and the content of potassium ions in the dry biomass is 0.15 percent; the removal rate of chloride ions is 88.6 percent, the removal rate of potassium ions is 90.6 percent, and the ash melting point is 1365 ℃ (GB/T30726-2014).

Example 6

(1) Crushing and screening straws: crushing a corn straw biomass raw material into a biomass material with the length of 5-10 cm and the diameter of not more than 1 cm;

(2) soaking and washing treatment: soaking the corn straw biomass obtained in the step 1) by using 0.1mol/L sodium hydroxide aqueous solution, wherein the water temperature of the sodium hydroxide aqueous solution is 95 ℃, and the mass ratio of the sodium hydroxide aqueous solution to the corn straw biomass obtained in the step 1) is 20: 1, soaking for 10 minutes;

(3) mechanical dehydration treatment: reducing the moisture mass content of the biomass obtained in the step 2) to 50% through natural dehydration and mechanical filter pressing dehydration;

(4) the dry chlorine ion content of the biomass raw material is 1.14 percent, and the potassium ion content is 1.6 percent; after the treatment by the method, the content of chloride ions in the dry biomass is 0.06 percent, and the content of potassium ions in the dry biomass is 0.1 percent; the chloride ion removal rate is 95 percent, the potassium ion removal rate is 93.8 percent, and the ash melting point is 1390 ℃ (GB/T30726-2014).

Example 7

(1) Crushing and screening straws: crushing a corn straw biomass raw material into a biomass material with the length of 1-5 cm and the diameter of not more than 1 cm;

(2) soaking and washing treatment: soaking the corn straw biomass obtained in the step 1) in 60 ℃ tap water (without adding acid or alkali), wherein the mass ratio of the tap water to the corn straw biomass obtained in the step 1) is 10:1, and the soaking time is 60 minutes;

(3) mechanical dehydration treatment: reducing the moisture mass content of the biomass obtained in the step 2) to 50% through natural dehydration and mechanical filter pressing dehydration;

(4) the dry chlorine ion content of the biomass raw material is 1.14 percent, and the potassium ion content is 1.6 percent; after the treatment by the method, the content of chloride ions in the dry biomass is 0.687%, and the content of potassium ions in the dry biomass is 1.022%; the removal rate of chloride ions is 39.7 percent, the removal rate of potassium ions is 36.1 percent, and the ash melting point is 1110 ℃ (GB/T30726-2014).

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.