阅读说明：本技术 利用纳滤海水捕集二氧化碳制备纳米碳酸钙镁材料的方法 (Method for preparing nano calcium carbonate magnesium material by using nanofiltration seawater to trap carbon dioxide ) 是由 王仁宗 熊良峰 刘裕 于 2021-06-23 设计创作，主要内容包括：本发明是一种利用纳滤海水捕集二氧化碳制备纳米碳酸钙镁材料的方法,其特征在于先用纳滤过滤器对海水进行浓缩处理,提高海水的盐度,然后将浓缩海水抽入二氧化碳烟气吸收装置,在控制海水温度、pH值的条件下,使海水中钙镁离子与烟气中二氧化碳反应生成碳酸钙镁,然后进行机械脱水和烘干处理,最后得到纳米级碳酸钙镁材料。本发明不仅可以减少烟气中二氧化碳的排放,同时可以利用烟气中的二氧化碳来制备纳米级碳酸钙镁材料,可谓一举两得。(The invention relates to a method for preparing nano calcium carbonate magnesium material by using nanofiltration seawater to trap carbon dioxide, which is characterized in that a nanofiltration filter is used for concentrating seawater to improve the salinity of the seawater, then the concentrated seawater is pumped into a carbon dioxide flue gas absorption device, calcium magnesium ions in the seawater and carbon dioxide in the flue gas are reacted to generate calcium magnesium carbonate under the conditions of controlling the temperature and the pH value of the seawater, then mechanical dehydration and drying treatment are carried out, and finally the nano calcium carbonate magnesium material is obtained. The method can reduce the emission of carbon dioxide in the flue gas, and can prepare the nano calcium magnesium carbonate material by using the carbon dioxide in the flue gas, thereby achieving two purposes.)

1. The method for preparing the nano calcium carbonate magnesium material by using the nano-filtration seawater to trap the carbon dioxide is characterized by comprising the following steps:

introducing seawater into a clarification tank, naturally settling partial silt in the seawater in the clarification tank, clarifying, and pumping into a nanofiltration filter through a water pump;

step two, after the clarified seawater in the step one is processed by a nanofiltration filter, obtaining desalinated water and high-salinity seawater, wherein the salinity of the high-salinity seawater is 52.5-105 permillage;

pumping the high-salinity seawater in the third step into a flue gas absorption device (a carbonization tower), injecting carbon dioxide flue gas from the bottom of the device, controlling the amount of the flue gas to control the temperature of the seawater to be 20-45 ℃, simultaneously adding any one or a mixture of more than two of NaOH solution, ethanolamine and diethanolamine to control the pH value of the seawater to be 8-8.5, and under the alkalescent condition, adding CO in the flue gas₂Reacting with calcium and magnesium ions in the seawater to generate precipitates of calcium carbonate and magnesium carbonate;

and step four, adopting a plate-and-frame filter press or a centrifuge to dehydrate the seawater containing the calcium carbonate and the magnesium carbonate obtained in the step three, controlling the water content to be 30-55 wt%, then drying the seawater through a tube bundle dryer or a roller dryer to dry the seawater to be less than 0.5 wt%, and finally obtaining the nano calcium carbonate magnesium material.

2. The method for preparing nano calcium magnesium carbonate material by using nanofiltration seawater for capturing carbon dioxide according to claim 1, wherein the method comprises the following steps: in the third step, the carbon dioxide flue gas comes from the combustion of coal, petroleum, natural gas, straws and garbage, or the steel making, or the cement industrial production.

3. The method for preparing nano magnesium calcium carbonate material by using nanofiltration seawater for capturing carbon dioxide according to claim 1 or 2, wherein the method comprises the following steps: and the carbon dioxide flue gas in the third step needs to be subjected to dust removal treatment through a spray tower in advance until the concentration of the carbon dioxide flue gas particles is reduced to below 20 ppm.

Technical Field

The invention relates to a method for capturing, sealing and utilizing carbon dioxide, in particular to a method for preparing a nano calcium magnesium carbonate material by capturing carbon dioxide by using nanofiltration seawater.

Background

The nano calcium carbonate is calcium carbonate product with particle size of 0-100nm, including superfine calcium carbonate (particle size of 20-100 nm) and superfine calcium carbonate (particle size less than or equal to 20 nm). The nano calcium carbonate has the advantages of fine particles, large specific surface area, high surface activation rate, high whiteness and the like, and is one of the nano materials which can be industrially produced and applied on a large scale at present. The nano calcium carbonate is low in cost and excellent in performance, so that the nano calcium carbonate is widely applied to the industries of rubber, plastics, paper making and the like, and can be used as a substitute of expensive powder materials such as white carbon black, titanium dioxide and the like.

The nano magnesium carbonate is an inorganic chemical raw material with wide application, has large market demand space and shows a trend of increasing year by year. Particularly, the superfine light magnesium carbonate product is the product which is the hottest in the world and has continuously developed application, so that the development of high-grade and functional products, and the product with high refinement degree and high added value is a major trend of the development of the magnesium salt industry.

The method can reduce the emission of carbon dioxide in the flue gas, and can prepare the nano calcium magnesium carbonate material by using the carbon dioxide in the flue gas, thereby achieving two purposes.

Disclosure of Invention

In order to reduce the emission of carbon dioxide in flue gas and simultaneously fix and utilize the carbon dioxide, the invention provides a method for preparing a nano calcium magnesium carbonate material by capturing the carbon dioxide by using nanofiltration seawater.

The technical scheme of the invention is as follows:

the method for preparing the nano calcium carbonate magnesium material by using the nano-filtration seawater to trap the carbon dioxide is characterized by comprising the following steps:

introducing seawater into a clarification tank, naturally settling partial silt in the seawater in the clarification tank, clarifying, and pumping into a nanofiltration filter through a water pump;

step two, after the clarified seawater in the step one is processed by a nanofiltration filter, obtaining desalinated water and high-salinity seawater, wherein the salinity of the high-salinity seawater is 52.5-105 permillage;

pumping the high-salinity seawater in the third step into a flue gas absorption device (a carbonization tower), injecting carbon dioxide flue gas from the bottom of the device, controlling the amount of the flue gas to control the temperature of the seawater to be 20-45 ℃, and simultaneously adding any one or a mixture of more than two of NaOH solution, ethanolamine and diethanolamine to control the pH value of the seawater to be 8-8.5CO in flue gas under alkalescent conditions₂Reacting with calcium and magnesium ions in the seawater to generate precipitates of calcium carbonate and magnesium carbonate;

and step four, adopting a plate-and-frame filter press or a centrifuge to dehydrate the seawater containing the calcium carbonate and the magnesium carbonate obtained in the step three, controlling the water content to be 30-55 wt%, then drying the seawater through a tube bundle dryer or a roller dryer to dry the seawater to be less than 0.5 wt%, and finally obtaining the nano calcium carbonate magnesium material.

In the third step, the carbon dioxide flue gas comes from the combustion of coal, petroleum, natural gas, straws and garbage, or the steel making, or the cement industrial production.

And the carbon dioxide flue gas in the third step needs to be subjected to dust removal treatment through a spray tower in advance until the concentration of the carbon dioxide flue gas particles is reduced to below 20 ppm.

The method can reduce the emission of carbon dioxide in the flue gas, and can prepare the nano calcium magnesium carbonate material by using the carbon dioxide in the flue gas, thereby achieving two purposes.

Detailed Description

The present invention will be further described with reference to examples.

Example 1

1) Pumping seawater of a certain seaside city into a clarification tank, naturally settling for 12h, taking surface clear liquid, pumping the surface clear liquid into a nanofiltration device, returning low-salinity seawater treated by the nanofiltration device to the sea or using the low-salinity seawater as industrial water, and using the high-salinity seawater as a carbon dioxide absorption liquid with the salinity of 52.5-65 per thousand;

2) after the flue gas of the seashore urban thermal power plant is subjected to desulfurization and dust removal treatment, the solid particles are reduced to be below 20 ppm;

3) pumping high salinity seawater into a flue gas absorption device, namely a carbonization tank, and injecting flue gas from the bottom of the carbonization tank; controlling the temperature of the seawater to be 20-30 ℃ by controlling the smoke gas amount, controlling the pH value of the seawater to be 8-8.5 by adding a NaOH solution, and reacting calcium and magnesium ions in the seawater with carbon dioxide under a weak alkaline condition to form precipitates of calcium carbonate and magnesium carbonate;

4) and (3) dehydrating the seawater containing calcium carbonate and magnesium carbonate in the step (3) by using a plate filter press, controlling the water content to be 45-55 wt%, drying by using a tube bundle dryer, and drying the water content to be 0.45 wt% to finally obtain the calcium carbonate magnesium material with the particle size of 40-100 nm.

Example 2

1) Pumping seawater of a certain seaside city into a clarification tank, naturally settling for 12h, and pumping surface layer clear liquid into a nanofiltration device. The low salinity seawater treated by the nanofiltration device is returned to the sea or used as industrial water, the high salinity seawater is used as carbon dioxide absorption liquid, and the salinity is 65-80 per mill;

2) after the flue gas of the seashore urban thermal power plant is subjected to desulfurization and dust removal treatment, the solid particles are reduced to be below 20 ppm;

3) pumping the high salinity seawater into a flue gas absorption device, namely a carbonization tank, and injecting flue gas from the bottom of the carbonization tank. Controlling the temperature of the seawater to be 30-40 ℃ by controlling the smoke gas amount, controlling the pH value of the seawater to be 8-8.2 by adding ethanolamine, and reacting calcium and magnesium ions in the seawater with carbon dioxide under a weak alkaline condition to form precipitates of calcium carbonate and magnesium carbonate;

4) and (3) dehydrating the seawater containing calcium carbonate and magnesium carbonate in the step (3) by using a centrifugal machine, controlling the water content to be 35-45 wt%, drying by using a tube bundle dryer, and drying the water content to be below 0.40% to finally obtain the calcium carbonate magnesium material with the particle size of 40-100 nm.

Example 3

1) Pumping seawater of a certain seaside city into a clarification tank, naturally settling for 12h, and pumping surface layer clear liquid into a nanofiltration device. The low salinity seawater treated by the nanofiltration device is returned to the sea or used as industrial water, the high salinity seawater is used as carbon dioxide absorption liquid, and the salinity is 80-105 per mill;

2) after the flue gas of the seashore urban thermal power plant is subjected to desulfurization and dust removal treatment, the solid particles are reduced to be below 20 ppm;

3) pumping the high salinity seawater into a flue gas absorption device, namely a carbonization tank, and injecting flue gas from the bottom of the carbonization tank. Controlling the temperature of the seawater to be 40-45 ℃ by controlling the amount of flue gas, controlling the pH value of the seawater to be 8.3-8.5 by adding ethanolamine and diethanolamine amine, and reacting calcium and magnesium ions in the seawater with carbon dioxide under a weak alkaline condition to form precipitates of calcium carbonate and magnesium carbonate;

4) and (3) dehydrating the seawater containing calcium carbonate and magnesium carbonate in the step (3) by using a centrifugal machine, controlling the water content to be 30-35 wt%, and then drying by using a drum dryer until the water content is below 0.35%, so as to finally obtain the calcium carbonate magnesium material with the particle size of 40-100 nm.