Zero-emission utilization technology of carbon dioxide generated by combustion

Abstract

The zero emission utilization technology of carbon dioxide generated by combustion is based on a Solvar ammonia alkali method, carbon dioxide in flue gas generated by combustion of fossil fuel, residual oil, garbage, agricultural straw and other wastes is washed with water, ammonia gas, industrial salt and water are added for a reaction, 50% of carbon dioxide is absorbed and utilized, and the carbon dioxide is recycled. The other 50% of carbon dioxide discharged in the washing process of processing the baking soda into the soda ash is recycled again, that is, a mixture of the carbon dioxide, the water and the baking soda which is not fully reacted is collected from the gas discharged by calcination, and after a second chelation reaction, baking soda and ammonium chloride which are as many as those of a Solvar ammonia-soda method are produced twice, and the baking soda is recycled. Zero emission and utilization of carbon dioxide are achieved, and the yield of soda ash and ammonium chloride is doubled. The technology can be applied to enterprises with flue gas emission through combustion, carbon dioxide in the flue gas is converted into industrial raw material soda ash and agricultural chemical fertilizer ammonium chloride with economic value, and economic benefits are improved while zero emission of carbon dioxide is achieved.

Description

Technical Field

[0001] The flue gas produced by combustion is washed with water and then stored. The carbon dioxide in the flue gas is then reacted with ammonia, industrial salt and water using the Solvay ammonia-soda process. 50% of the carbon dioxide is absorbed and utilized to be converted into soda ash and ammonium chloride. The other 50% of the carbon dioxide, water and the incompletely reacted baking soda mixture emitted in the washing process of processing baking soda into soda ash are recovered again. After the second chelating reaction, the same amount of baking soda and ammonium chloride as in the Solvay ammonia-soda process is produced. Background Art

[0002] The Solvay process for making soda ash was invented in the 1860s. Its chemical reaction formula is as follows: CO 2 +NH 3 +H 2 O + NaCl → NaHCO 3 +NH 4 Cl formula (a) 2NaHCO 3 →Na 2 CO 3 +H 2 O+CO 2 Formula (b) In the 1860s, the carbon dioxide emitted by humans in the atmosphere did not cause global warming. At that time, the Solvay Ammonia-Soda Process was based on the production of soda ash, while the rest of the carbon dioxide was still released into the atmosphere. Now, due to the excessive carbon dioxide emitted by humans in the atmosphere, global warming has occurred, causing more and more frequent and severe extreme weather hazards. Therefore, we seized the opportunity of adjusting the national macroeconomic policy and upgrading the economic model of energy conservation and carbon reduction in enterprises. On the basis of the Solvay Ammonia-Soda Process, we have developed a chemical absorption method to convert all the carbon dioxide produced by combustion into industrial raw materials with economic value, soda ash and agricultural fertilizer ammonium chloride after washing. Not only does it directly absorb and utilize the emitted carbon dioxide, but the soda ash obtained is also a strategic material for industry. China's soda ash consumption accounts for about 20% of the world's consumption, and the demand is strong. In addition, ammonium chloride can amplify the capture of carbon dioxide in the atmosphere through agricultural planting, thus embarking on a path of carbon reduction. Summary of the invention

[0003] The flue gas generated by combustion is washed with water and compressed and stored in a carbon storage tank. The scale of soda ash and ammonium chloride production is designed according to the daily carbon dioxide emission, so as to achieve the purpose of absorbing and utilizing the carbon dioxide in the emitted flue gas. In the first reaction, 50% of the carbon dioxide will be utilized in the reaction of carbon dioxide, ammonia, water and sodium chloride. After the improvement of the Solvay ammonia-soda process, the other 50% of the carbon dioxide is also absorbed and utilized after the secondary chelation reaction (see the attached figure of the specification). The main aspect of the improvement is to pump the other 50% of the carbon dioxide from the exhaust pipe A port on the baking kiln into the bottom air inlet B of the washing tower by pumping. After centrifugal separation, the mixture of baking soda and ammonium chloride obtains ammonium chloride, and then baking soda obtains soda ash, carbon dioxide and water. In the process practice, formula (b) is executed in the D kiln. As long as it is slightly tilted from the top at an angle, the air inlet end pipe E port faces downward, and fresh centrifuged baking soda will be produced at the lower end of the external end pipe. However, if the fresh centrifuged baking soda is loaded into the air inlet of the kiln, the reaction of formula (b) will be difficult and incomplete. Only a small amount of newly formed soda ash above 350 degrees will mix with wet baking soda to form a cake-like mass, resulting in incomplete and insufficient reaction of formula (b). In order to solve this problem, we mix a small amount of newly generated wet baking soda with a large amount of soda ash powder, which is previously obtained from the external air outlet F, and fill it into the air inlet E, so that qualified soda ash powder can be obtained. Therefore, the carbon dioxide emitted in the process of processing baking soda into soda ash and returning carbon dioxide to the scrubbing tower is recovered, and the carbon dioxide, water and incompletely reacted baking soda mixture are continuously recovered and repeatedly mixed with the newly formed soda ash powder, which will eventually become soda ash and produce the same amount of baking soda and ammonium chloride as the Solvay ammonia-soda process, achieving the purpose of zero emission of carbon dioxide and wastewater. The carbon dioxide, water and incompletely reacted baking soda mixture are reused again, and the production of soda ash and ammonium chloride is doubled compared with the Solvay ammonia-soda process, thereby improving economic benefits and achieving zero emission of carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Figure 1 This is a process flow chart for zero emission utilization of carbon dioxide produced by combustion. Δ represents a mixture of baking soda and soda ash. DETAILED DESCRIPTION

[0005] First, we need to implement a waste incineration power plant, transform the exhaust system, and use this technology to add ammonia, water, and salt to convert the carbon dioxide in the flue gas into soda ash and ammonium chloride, and then promote it to other enterprises that burn and emit carbon dioxide. According to calculations, the absorption and utilization of 1 ton of carbon dioxide will produce 3.6 times of soda ash and ammonium chloride, of which ammonium in ammonium chloride accounts for about 33% and chlorine accounts for about 67%. According to the current market price, ammonia is 2,700 yuan / ton, industrial salt is 280 yuan / ton, soda ash is 1,500 yuan / ton, and ammonium chloride is 1,200 yuan / ton. The consumption of ammonia in 3.6 tons of ammonium chloride is about 3.6×33%=1.188 tons, with a cost price of 3,207.6 yuan, and the consumption of industrial salt (including the industrial salt required for sodium in soda ash) is about 4 tons, with a cost price of 1,120 yuan, and the total cost price is 4,328 yuan. The sodium in 3.6 tons of soda ash is obtained from industrial salt, and its cost has been accounted for in ammonium chloride. The cost of other carbon and nitrogen content is almost zero, so the cost of soda ash is almost zero. The output value is calculated to be 3.6×(1500+1200)=9720 yuan, and the gross profit is about 5392 yuan. That is to say, a gross profit of about 5000 yuan will be obtained for processing 1 ton of carbon dioxide. The internationally used amine chemical solvents can capture more than 98% of carbon dioxide from waste gas, but the capture cost is relatively high. The Solvay ammonia-soda improvement method can also directly capture more than 98% of carbon dioxide from waste gas and convert it into industrial raw materials soda ash and agricultural fertilizer ammonium chloride with economic value. Waste utilization creates economic value and can obtain huge economic benefits. Take a medium-sized city that produces 2,000 tons of garbage per day. For example, the carbon dioxide in the flue gas emitted by garbage combustion power generation is treated with the Solvay ammonia modified process. The combustion value of 20 tons of garbage is equivalent to 1 ton of 5,000 kcal standard coal. If 300 grams of coal generates 1 kWh of electricity, 100 tons of standard coal will be saved per day, 36,500 tons of standard coal will be saved per year, 333,333 kWh of electricity will be generated per day, and 120 million kWh of electricity will be generated per year. Without considering the economic benefits brought by electricity, we can estimate its economic value by converting carbon dioxide in the flue gas into soda ash and ammonium chloride. The daily emission of carbon dioxide is about 270 tons, and the annual emission is 98,550 tons. After all the conversions, the daily gross profit is 1.35 million yuan, and the annual gross profit is about 490 million yuan. Therefore, this is a technology that not only solves the problem of carbon dioxide emission polluting the environment, but also turns waste into treasure to increase economic benefits. Moreover, the electricity generated by garbage after treatment is clean energy. In addition, the amount of carbon dioxide captured from the atmosphere by ammonium chloride through crops means that this energy is a clean energy with negative carbon emissions.

Claims

1. An improved Solvay ammonia-soda process is used to absorb and utilize 50% of the carbon dioxide in the flue gas emitted from combustion, and then the other 50% of the carbon dioxide emitted in the washing process of processing baking soda into soda ash is recovered again, that is, a mixture of carbon dioxide, water and incompletely reacted baking soda is collected from the calcination exhaust gas, and after a secondary chelating reaction, the same amount of baking soda and ammonium chloride as in the Solvay ammonia-soda process is produced for the second time, thereby achieving zero emission of carbon dioxide and doubling the output of soda ash and ammonium chloride compared to the Solvay ammonia-soda process.

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