TWI472381B - Method for improving carbonation conversion of alkaline solid waste - Google Patents

Description

Method for increasing carbonation conversion rate of alkaline solid waste

The invention relates to a method for improving the conversion rate of carbonation reaction of alkaline industrial solid waste, in particular to a method for using a rotary filling reactor to increase the conversion rate of waste carbonation reaction and reduce the reaction time.

In recent years, fossil fuels have been used more and more to meet the increase in energy demand, resulting in an increase in the concentration of carbon dioxide in the atmosphere. The concentration of CO _{2 in the} range from 275 to 285 ppm before the industrial revolution (AD 1750) was increased to 385. Ppm (2010), a global increase of approximately 100 ppm (36%) over the past 250 years. Because of the carbonation process of alkaline solid waste, the principle is to permanently convert carbon dioxide into carbonates, such as calcium carbonate, so that carbon dioxide generated by industrial processes can be removed, and on the other hand, waste can be significantly improved. The nature of chemistry and physics reduces the impact of waste on the environment and reduces the cost of stabilization of waste.

The basic concept of carbonation is to mimic the weathering process in nature. Alkaline earth metal oxides react with carbon dioxide to form stable and less soluble carbonates. Usually calcium and magnesium oxides are the most attractive alkaline earth metal oxides. As shown in equations (a) and (b), in general, carbonation must provide the corresponding alkaline earth metal ions, such as divalent calcium and magnesium. Ions neutralize carbonic acid. Compared to natural weathering, carbonation can completely reduce the reaction time to a few days or even hours. In addition, carbonation has some potential advantages: First, carbonation products, such as calcium and magnesium carbonates, are thermodynamically quite stable in the absence of acidification; in addition, carbonation is an exothermic reaction. Therefore, the cost and energy consumption can be relatively reduced.

Alkaline solid waste is usually rich in calcium and magnesium oxide. In addition, it has been pointed out in many studies that after alkaline carbon waste is carbonated, it may contain trace amounts of heavy metals such as lead, nickel, cadmium, etc. The oozing has the effect of restraining and reducing. As a result, significant improvements in chemical and physical properties can be achieved for alkaline solid waste, reducing its impact on the environment, and carbonated alkaline solid waste can be reused in a variety of applications, such as infrastructure and Building materials.

According to a study by Chang et al. in 2011, in the traditional batch reactor, the experiment of carbonation of alkaline solid waste, at 60 minutes, the carbonation reaction has almost reached equilibrium, at atmospheric pressure, 60 ° C, When the liquid-solid ratio is 10, the maximum carbonation conversion rate of cement hearth (BHC) and converter stone (BOF) is 48% and 68%, respectively. According to the 2009 study by Huntzinger et al., the carbonation experiment was carried out using the bottom slag (CKD) of the cement kiln. The carbonation conversion rate of the reaction time was 70.6% under normal temperature and pressure.

In the past, most of the research focused on the accelerated carbonation of alkaline solid waste in traditional batch reactors (such as bubble tanks), but because of the limited mass transfer effect of traditional batch reactors, Most of them must pass through high pressure, high temperature and long time to carry out the reaction in order to increase the carbonation conversion rate. In the past studies, the improvement of the conversion rate of carbonation reaction of alkaline solid waste was not effectively improved. The problem that is currently being solved is how to increase the conversion rate, reduce the reaction time, and reduce the carbonation reaction. Handling costs and reducing energy consumption.

The present inventors have actively pursued research and development in view of the limitation of the conversion rate of the carbonation reaction of the existing alkaline solid waste and the long time required in the conventional batch reactor, in order to solve the above-mentioned problems. Through continuous experimentation and efforts, the present invention has finally been developed.

The main object of the present invention is to provide a method for improving the conversion rate of carbonation reaction of alkaline solid waste by using a rotary charging reactor under normal temperature and normal pressure, and reducing the reaction time.

In order to achieve the above object, the present invention is achieved by the following technical means, wherein the present invention comprises the following steps: a filling step of filling: filling a filling into a rotary filling reactor, the rotary filling reactor having a The casing has a liquid injection port on the upper side of the casing for injecting alkaline solid waste and additives, a gas injection port on the side wall, and a liquid collecting port on the lower side, and a rotating groove capable of rotating in the casing The rotating tank is provided with a filling reaction zone for filling the filling, the side wall of the filling reaction zone is for the waste and the additive to pass through; the centrifugal rotating step is: driving the rotating groove by a motor, so that the rotating groove can be relatively rotated and filled The reactor is rotated; the alkaline solid waste solution injection step is: injecting the alkaline solid waste solution from the solution injection port into the rotary tank; the conversion step is: using the rotary centrifugal force of the rotary tank to pass the alkaline solid waste solution Filling the filling in the reaction zone while passing the gas injection port to the reaction gas for the conversion reaction; Step: system which will be collected by the liquid collection ports by an alkaline solid waste filling the reaction solution after the reaction zone.

The above alkaline solid waste solution contains an alkaline solid waste and a liquid phase carrier.

The above alkaline solid waste includes steel slate, coal slag fly ash, incinerated bottom slag, cement kiln bottom slag, air pollution control equipment fly ash, and the like.

The above alkaline solid waste is a solid waste containing an alkaline earth metal compound.

The above liquid carrier contains water.

The alkaline earth metal compound contains calcium oxide or magnesium oxide.

The above fillers include stainless steel, alkaline earth metal compounds, alumina, resins, zeolites, silicones, and activated carbon.

The above reaction gas system includes carbon dioxide.

By rotating the centrifugal force, the alkaline solid waste solution is given kinetic energy to fill the reaction zone, and in this state, the conversion rate of the carbonation reaction of the alkaline solid waste can be improved, and it is proved by experiments that the method is processed by the method of the present invention. The alkaline solid waste has a higher conversion rate of carbonation than the alkaline solid waste treated by the conventional batch reaction, and the treatment time is shorter than the conventional method, so that the stabilization of the alkaline solid waste can be reduced. Cost, and can use the carbon dioxide produced by the industrial process itself to reduce carbon dioxide emissions and slow down the greenhouse effect.

Referring to the first and second figures, the method for improving the carbonation conversion rate of the alkaline solid waste of the present invention comprises the following steps: filling step (1): filling the filling into a rotary filling reactor (6) The rotary charging reactor (6) has a casing (7), and the upper side of the casing (7) is provided with a solution injection port (8) and a gas discharge port (9), and a gas injection port is provided on the side wall. (10), the lower side is provided with a solution collecting port (11), and the casing (7) is internally provided with a rotatable rotating groove (13), and the filling wall is provided with a filling reaction zone for filling (12) The side wall of the filling reaction zone (12) is permeable to the alkaline solid waste solution; the centrifugal rotation step (2): the rotation of the rotating groove (13) is driven by a motor (14), so that the rotating groove (13) is relatively Rotating the filling reactor (6) for rotation, the motor (14) is disposed below the rotary filling reactor (6), and its power output shaft is connected to the rotating tank (13) through the rotary filling reactor (6); Alkaline solid waste solution injection step (3): injecting the reaction alkaline solid waste solution into the rotary tank (13) from the solution injection port (8); Step (4): using the centrifugal force of the rotating tank (13) to pass the alkaline solid waste solution into the filling in the reaction zone (12), and simultaneously passing the reaction gas through the gas injection port (10) to carry out a conversion reaction; Recovery step (5): The alkaline solid waste solution is collected from the solution collection port (11) by the reaction of filling the reaction zone (12).

Example

Firstly, the carbonation reaction test of the alkaline solid waste is carried out by using the method of the invention. The medium steel converter stone is used as the raw material, the additive used is deionized water, the filling material is stainless steel wire mesh, and the reaction gas is pure carbon dioxide gas. The reaction data is shown in Table 1.

Then, the effects of the flow rate of different alkaline solid waste solutions on the conversion rate were tested. The test instruments were the same as the above experiments, and the data obtained are shown in Table 2.

Control group

Batch carbonation of medium steel converter stone (BOF) with traditional batch bubble tank. Reaction conditions: alkaline solid waste particle size is 44 μm, liquid-solid ratio (mL/g) is 10, gas pressure is 1.5. Kg/cm ² , the flow rate of the alkaline solid waste solution is 1.0 L/min, and the conversion rate and time are shown in Table 3.

It can be seen from Table 1 that the method of the present invention can obtain a carbonation conversion rate of up to 96.6%, and does not require a long reaction. As can be seen from the data in Table 3, the conventional batch bubble tank method is transformed after a reaction of up to one hour. The rate is only up to 67.9%, so it can be confirmed that the present invention can obtain not only a short treatment time but also a high carbonation conversion rate of alkaline solid waste.

From the results of Table 2, it can be found that in the flow range of 0.5 to 1.5, the carbonation conversion rate of the thirty minutes can reach 87% or more, and the conversion of the method of the present invention is compared with the long-term reaction of the conventional batch bubble tank. The rate effect is significantly higher.

In addition, according to the 2007 report of the laboratory, the blast furnace carbonation reaction test of the medium steel blast furnace was carried out in a conventional pressure stirring tank. Under similar reaction results, the operating conditions were 700 psi, the reaction temperature was 160 ° C, and the reaction time was It takes 12 hours to get 85.4% of the results. It can be seen that the method of the present invention has a significant improvement effect on the conversion rate of carbonation reaction of alkaline solid waste under normal temperature and normal pressure.

(1). . . Filling step

(2). . . Centrifugal rotation step

(3). . . Alkaline solid waste solution injection step

(4). . . Conversion step

(5). . . Recovery step

(6). . . Rotary filling reactor

(7). . . case

(8). . . Solution injection port

(9). . . Gas discharge

(10). . . Gas injection port

(11). . . Solution collection port

(12). . . Filling reaction zone

(13). . . Rotating slot

(14). . . motor

The first figure is a schematic flow chart of the present invention.

The second drawing is a schematic view of the structure of a rotary filling reactor used in the process of the present invention.

(1). . . Filling step

(2). . . Centrifugal rotation step

(3). . . Alkaline solid waste solution injection step

(4). . . Conversion step

(5). . . Recovery step

Claims (7)

A method for improving the carbonation conversion rate of an alkaline solid waste comprises the steps of: filling a filling step: filling a filling into a rotary filling reactor, the rotating filling reactor having a casing and an upper side of the casing a solution injection port is provided for injecting the alkaline solid waste solution, a gas injection port is arranged on the side wall, and a solution collection port is arranged on the lower side, and a rotary groove capable of rotating in the casing is arranged inside the casing, and the rotation groove is provided therein Filling the reaction zone with the filling filling, the side wall of the filling reaction zone is transparent to the solid solid waste solution; and the centrifugal rotating step is: rotating the rotating groove by a motor, so that the rotating groove can rotate relative to the rotating filling reactor; The alkaline solid waste solution injection step is: injecting the alkaline solid waste solution from the solution injection port into the rotary tank; the conversion step: using the rotary centrifugal force of the rotary tank to pass the alkaline solid waste solution into the reaction zone a filling, which is simultaneously passed through a gas injection port to carry out a conversion reaction, wherein the reaction gas system includes carbon dioxide Recovery step: based solution will be collected by the waste collection port through alkaline solid solution after the reaction the reaction zone is filled. The method for improving the carbonation conversion rate of an alkaline solid waste according to the first aspect of the invention, wherein the alkaline solid waste solution comprises an alkaline solid waste and a liquid carrier. The method for improving the carbonation conversion rate of an alkaline solid waste according to the second aspect of the patent application, wherein the alkaline solid waste comprises steel slate, cinder fly ash, incinerated bottom slag, cement kiln bottom slag, Air pollution control equipment fly ash. A method for increasing the carbonation conversion rate of an alkaline solid waste as described in claim 2, wherein the liquid phase carrier comprises water. The method for improving the carbonation conversion rate of an alkaline solid waste according to the second aspect of the patent application, wherein the alkaline solid waste is an alkaline solid waste containing an alkaline earth metal compound substance. The method for improving the carbonation conversion rate of an alkaline solid waste according to the fifth aspect of the invention, wherein the alkaline earth metal compound material comprises calcium oxide or magnesium oxide. The method for improving the carbonation conversion rate of an alkaline solid waste according to the first aspect of the invention, wherein the filler comprises stainless steel, an alkaline earth metal compound, alumina, a resin, a zeolite, a silicone, and an activated carbon.