Rapid detection device applied to soluble chloride ion concentration in fire coal

Abstract

The utility model discloses a rapid detection device applied to the concentration of soluble chloride ions in fire coal. The rapid detection device comprises a sampling device, a sample preparation device, an electrolysis device and an absorption device, the electrolysis device comprises an electrolytic tank and a plurality of groups of anode and cathode plates connected in series; an air bag is arranged above the electrolytic tank; the absorption device comprises a piston mixer, the piston mixer has a gas and solution volume metering function, and the piston mixer is connected with a gas bag to meter the gas volume change before and after the reaction. According to the detection device disclosed by the utility model, the chloride ion concentration is calculated by utilizing the volume change in the process of electrolysis and gas absorption reaction; the electrolysis device disclosed by the utility model has a 180-degree reversing function, and an aqueous solution in the electrolytic tank flows back and forth under the action of gravity; the reduction efficiency of Cl <-> is improved, and Cl <-> is fully converted into Cl2. The detection device disclosed by the utility model provides a new thought for carrying out normalized detection on the concentration of the chloride ions in the fire coal.

Description

Technical Field

[0001] The utility model belongs to the technical field of coal quality monitoring in coal-fired power plants, and particularly relates to a rapid detection device for the concentration of soluble chloride ions in coal. Background Art

[0002] The variation in chloride ion concentration in my country's coal is due to both natural and human factors. Natural factors are related to the coal source; the most prominent human factor is the widespread use of antifreeze during coal transportation in winter. After combustion in the boiler, the majority of the chloride ions in the coal are concentrated in the limestone-wet desulfurization system along with the boiler flue gas. Therefore, changes in chloride ion concentration in the coal directly affect the amount of high-salinity wastewater generated at the end of the process. In most coal-fired power plants, the rate of increase in chloride ion concentration in the desulfurization absorber slurry accelerates significantly during winter operation. From a plant-wide chloride ion balance, chloride ion transported into the desulfurization system via coal flue gas accounts for between 2 / 3 and 3 / 5 of the total chloride ion load, or more than half. Winter coal chloride ion concentrations are generally double those in summer, further increasing the proportion of chloride ion transported into the desulfurization system by flue gas. Therefore, comprehensively understanding the variations in chloride ion concentration in coal from different sources and over different time periods is crucial.

[0003] Antifreeze spraying method: First, pre-spray on the inner surface of the coal carriage, and then spray on the upper surface after the coal is loaded. Antifreeze is mainly divided into two categories: chloride and non-chloride. Typical components of chlorides are one or more of sodium chloride, calcium chloride, and magnesium chloride, and non-chloride components include potassium acetate, sodium acetate, potassium formate, ethanol, ethylene glycol, etc. Non-chloride antifreeze generally contains organic elements such as C, H, and O, and can be directly burned with coal without generating secondary pollution. At present, there are no mandatory regulations on the components of antifreeze products used in the coal transportation process, and chloride antifreeze is still the mainstream in the industry. Human factors cause the total amount of chloride ions to increase during the mining and sales of coal. As users, coal-fired power plants currently rarely pay enough attention to their process control.

[0004] Coal-fired power plants also don't routinely test for chloride ion concentrations in coal. GB / T 3558-2014, Determination of Chlorine in Coal, is the current standard for testing total chlorine in coal. Method A, high-temperature combustion decomposition-potentiometric titration, and Method B, Aishka mixture molten sample-potassium bisulfate titration, pre-treat coal samples by high-temperature calcination to convert all chlorine into HCl, which is then dissolved in water for testing. This method doesn't address how to ensure representativeness and uniformity during the sampling process for bulk raw coal. It's designed only for laboratory testing of incoming samples, and the laboratory testing process involves specialized procedures and human intervention, making automated sample processing and testing difficult. Utility Model Content

[0005] The purpose of the utility model is to provide a rapid detection device for the concentration of soluble chloride ions in coal, which solves the problem that the existing detection system for the concentration of chloride ions in coal is complex and difficult to realize automatic processing and detection of samples.

[0006] The technical solution adopted by the utility model is a rapid detection device for the concentration of soluble chloride ions in coal, which includes a sampling device, a sample preparation device, an electrolysis device, and an absorption device;

[0007] The sampling device includes an automatic sampling machine installed above the coal carriage, and the front end of the automatic sampling machine adopts a screw propulsion method to enter the interior of the coal carriage;

[0008] The sample preparation device includes a variable speed crusher and a coal-water dissolver equipped with a stirring device. The end of the automatic sampler is connected to the variable speed crusher; the variable speed crusher is connected to a compressed air purge device.

[0009] The electrolysis device includes an electrolytic cell and multiple sets of anode and cathode plates connected in series. An air bag is provided above the electrolytic cell, and the air bag has an external force squeezing function.

[0010] The absorption device comprises a piston mixer, which has the volume metering function of gas and solution, and is connected to the gas bag.

[0011] The utility model is also characterized in that:

[0012] The piston mixer includes a measuring cylinder with an upper opening, in which a piston is arranged to move along the inner wall of the measuring cylinder, and a closed cavity can be formed between the piston and the measuring cylinder; an air inlet pipe connected to the air bag is provided at the bottom of the measuring cylinder, and an electric valve a is provided on the air inlet pipe; a liquid inlet pipe is provided on the side of the measuring cylinder, and an electric valve b is provided on the liquid inlet pipe; an air outlet pipe is also provided on the piston, and an electric valve c is provided on the air outlet pipe.

[0013] The anode of the electrolysis device is made of carbon material with adsorption function, and the cathode is made of metal material. The voltage applied to each set of anode and cathode plates is greater than 3V.

[0014] The electrolysis device has a 180° inversion function, and the aqueous solution in the electrolysis cell flows back and forth under the action of gravity.

[0015] The sampling points of the automatic sampling machine are distributed as follows: the sampling method along the transverse section and longitudinal section of the coal transport carriage is three-point type, the first point is vertically downward, the second point is inclined 45-60 degrees to the left and deep into the inner wall of the carriage, and the third point is inclined 45-60 degrees to the right and deep into the inner wall of the carriage.

[0016] The beneficial effects of the utility model are:

[0017] 1) The utility model optimizes the coal sample collection method to ensure that the sampling process is representative.

[0018] 2) The variable speed crusher involved in the present invention should have the functions of high-speed rotation and low-speed rotation, and be equipped with a compressed air blowing device to be able to blow away the crushed coal powder in time.

[0019] 3) The electrolysis device involved in the utility model is composed of multiple sets of anode and cathode plates connected in series. The anode is made of carbon material with adsorption function, and the cathode is made of metal material. The voltage applied to each set of anode and cathode plates is greater than 3V, and the applied current is directly proportional to the chloride ion concentration in the aqueous solution. The electrolysis device has a 180° inversion function, and the aqueous solution in the electrolytic cell flows back and forth under the action of gravity. The purpose is to increase the Cl - Reduction efficiency, fully converting it into Cl2.

[0020] 4) The air bag involved in the present invention should have the expansion and extrusion functions under normal pressure to enable it to enter the piston mixer.

[0021] 5) The main body of the piston mixer involved in the present invention is a measuring cylinder with a volume recording function. Its design concept is to avoid mixing with ambient air or other inert gases during the measurement and absorption process.

[0022] 6) The whole process of the utility model can be operated unmanned, and continuous sampling and detection can be achieved according to the different sampling start times. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of a rapid detection device for the concentration of soluble chloride ions in coal.

[0024] Figure 2(a) is a longitudinal schematic diagram of coal carriage sampling.

[0025] Figure 2(b) is a horizontal schematic diagram of coal carriage sampling.

[0026] Figure 3 yes Figure 1 Schematic diagram of the piston mixer's operation process.

[0027] In the figure: 1. Automatic sampling machine, 2. Coal transport carriage, 3. Variable speed crusher, 4. Coal-water dissolver, 5. Electrolytic cell, 6. Air bag, 7. Piston mixer. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] Example 1

[0030] The utility model is applied to the rapid detection device of the concentration of soluble chloride ions in coal, such as Figure 1-3 As shown, it includes a sampling device, a sample preparation device, an electrolysis device, and an absorption device;

[0031] The sampling device includes an automatic sampling machine 1 arranged above the coal carriage 2, and the front end of the automatic sampling machine 1 is screw-propelled into the interior of the coal carriage 2;

[0032] The sample preparation device includes a variable speed crusher 3 and a coal-water dissolver 4 equipped with a stirring device. The end of the automatic sampler 1 is connected to the variable speed crusher 3; the variable speed crusher 3 is connected to a compressed air purge device;

[0033] The electrolysis device includes an electrolytic cell 5 and multiple groups of anode and cathode plates connected in series. An air bag 6 is provided above the electrolytic cell 5, and the air bag has an external force squeezing function.

[0034] The absorption device includes a piston mixer 7 , which has a volume metering function for gas and solution, and is connected to the air bag 6 .

[0035] The piston mixer 7 includes a measuring cylinder with an upper opening, in which a piston is provided that moves in contact with the inner wall of the measuring cylinder, and a closed cavity can be formed between the piston and the measuring cylinder; an air inlet pipe connected to the air bag 6 is provided at the bottom of the measuring cylinder, and an electric valve a is provided on the air inlet pipe; a liquid inlet pipe is provided on the side of the measuring cylinder, and an electric valve b is provided on the liquid inlet pipe; an air outlet pipe is also provided on the piston, and an electric valve c is provided on the air outlet pipe.

[0036] The anode of the electrolysis device is made of carbon material with adsorption function, and the cathode is made of metal material. The voltage applied to each set of anode and cathode plates is greater than 3V.

[0037] The electrolysis device has a 180° inversion function, and the aqueous solution in the electrolysis cell flows back and forth under the action of gravity.

[0038] Example 2

[0039] The utility model provides a rapid detection method for the concentration of soluble chloride ions in coal. Figure 1-Figure 2(b) As shown, the details are as follows:

[0040] (1) Sampling device and sampling method. The automatic sampling device adopts a spiral propulsion type. The front end enters the interior of the coal transport car, and the end transports the collected coal sample to the variable speed crusher. The sampling method of both the transverse section and the longitudinal section is three-point type. The first point is vertically downward, the second point is inclined 45-60 degrees to the left and deep into the inner wall of the car, and the third point is inclined 45-60 degrees to the right and deep into the inner wall of the car. In this way, a representative coal sample is obtained.

[0041] (2) Sample preparation device and sample preparation process. The sample preparation device uses a variable speed crusher with steel balls and is equipped with a compressed air purge device to crush and mix the raw coal during high-speed rotation. The ground coal powder is transferred to the coal-water dissolver after measurement. The coal-water dissolver is equipped with a stirring device to stir and mix with a certain amount of desalted water to promote the full dissolution of chloride ions in the coal powder. The coal-water ratio is configured at a ratio of less than 1kg:5L. The remaining coal powder is transported to the raw coal car or other designated collection area by compressed air purge. During the compressed air purge process, the crusher runs at a low speed to remove the residual coal powder in the crusher. The remaining coal water in the coal-water dissolver is discharged to the designated collection area.

[0042] (3) Electrolysis device and absorption process. The electrolysis device uses an inverted electrolytic cell. After the coal-water mixture, a certain volume V1 of filtered aqueous solution is taken and transferred to the electrolytic cell. The electrolytic cell is reversed and reciprocated according to the set time, and current is loaded at the same time to electrolyze the aqueous solution to obtain Cl2 gas. In this process, H2 gas is released along with the electrolysis of water molecules. The mixed gas is completely collected in the gas bag, and the waste alkali liquid in the electrolytic cell is discharged to the designated collection area. After the gas is completely collected, it is transferred to the piston mixer by extrusion at 0 degrees Celsius, and the gas volume is recorded by the piston mixer. Then, a fixed volume of sodium hydroxide aqueous solution is injected into the piston mixer. The piston mixer absorbs all the Cl2 in the mixed gas through high-speed rotation, and then releases all the H2 in the piston mixer. The measured H2 volume is Q1; the soluble Cl- concentration C in the coal sample is calculated.

[0043] The concentration of the sodium hydroxide aqueous solution is 0.05 to 0.1 mol / L.

[0044] Among them, the specific operation mode of the piston mixer is as follows Figure 3 As shown, the details are as follows:

[0045] Step 1: Initial state of the piston mixer: electric valves a, b, and c are all closed, and the mixed gas released during the electrolysis operation is collected in the air bag in advance;

[0046] Step 2: Mixed gas input state: electric valve a is opened, electric valves b and c are closed, the mixed gas in the air bag is squeezed externally, and all the mixed gas is delivered to the piston mixer. The piston moves upward and measures the gas volume Q0;

[0047] Step 3: Initial state of alkali solution injection: electric valve b is opened, electric valves a and c are closed, sodium hydroxide solution is injected, and the piston continues to move upward;

[0048] Step 4: Alkali solution injection is completed; the piston mixer rotates at high speed, and the alkaline solution fully contacts the mixed gas during the disturbance process and absorbs Cl2 in the mixed gas. The piston moves downward. During the high-speed rotation of the piston mixer, if the piston is in a downward movement state within the set time of 10 to 30 minutes, it means that the Cl2 in the mixed gas has not been fully absorbed. It is necessary to repeat step 3 until the piston mixer rotates at high speed and then stops within the set time of 10 to 30 minutes, which means that the Cl2 in the mixed gas has been fully absorbed; the cumulative volume of the injected sodium hydroxide solution is V2;

[0049] Step 5: Open the electric valve c, close the electric valves a and b, use the piston's own weight to release the H2 gas, and measure the volume change of the piston mixer, which is the H2 gas volume Q1. The absorption liquid is completely emptied.

[0050] Example 3

[0051] The raw coal purchased by the coal-fired power plant is transported to the designated sampling area by train or car, and the automatic sampling machine Figure 1 The method involves multi-point sampling of raw coal from the coal carriage. The collected samples are mixed in a variable-speed crusher and ground into fine coal powder (<0.2 mm). A quantitative sample of M kg of the uniformly mixed coal powder is collected, and a predetermined amount of demineralized water (V0 L) is added. After thorough stirring and dissolution, V1 L of aqueous solution is filtered and transferred to an electrolytic cell. Electrolysis of the aqueous solution releases Cl2 and H2, which are collected in a gas bag and measured in a volume of Q0 L. After the mixed gas is completely transferred to a piston mixer, an excess of sodium hydroxide aqueous solution is injected into the piston mixer. This fully washes the Cl2 from the mixed gas, releasing H2. The measured H2 volume is Q1 L. The concentration of the sodium hydroxide aqueous solution is 0.1 mol / L.

[0052] The volume change of the mixed gas during the absorption process is used for calibration. Under standard conditions, 1 mol of gas is 22.4 liters. The volume of Cl2 is obtained by the reduction in gas volume. The soluble Cl- concentration C in the coal sample is then calculated as:

[0053]

[0054] In order to ensure the accuracy of the test results, V1L aqueous solution can also be filtered out from the coal-water dissolver and compared by titration with silver nitrate standard solution to obtain the soluble Cl- concentration C0 in the coal sample; after multiple verification experiments, a fixed correction coefficient η is obtained to correct the calculation formula of Cl- concentration C.

[0055]

[0056] This utility model provides data support for the rational operation of coal-fired power plants by carrying out regular detection of chloride ion concentration in coal and storing basic data. In terms of production, it guides the rational optimization of coal-fired power plants' own resources, and at the same time has a certain restraining effect on the irregular use of antifreeze in upstream industries, further promoting the establishment of a sound circular economy system in upstream and downstream industries and promoting the conservation and intensive use of resources.

Claims

1. A rapid detection device for the concentration of soluble chloride ions in coal, characterized in that: It includes sampling device, sample preparation device, electrolysis device and absorption device; The sampling device comprises an automatic sampling machine (1) arranged above the coal transport carriage (2), wherein the front end of the automatic sampling machine (1) enters the interior of the coal transport carriage (2) in a spiral propulsion manner; The sample preparation device comprises a variable speed crusher (3) and a coal-water dissolver (4) equipped with a stirring device. The end of the automatic sampler (1) is connected to the variable speed crusher (3); the variable speed crusher (3) is connected to a compressed air purge device. The electrolysis device comprises an electrolytic cell (5) and a plurality of groups of anode and cathode plates connected in series, an air bag (6) is provided above the electrolytic cell (5), and the air bag has an external force squeezing function; The absorption device comprises a piston mixer (7), which has a volume metering function for gas and solution, and is connected to a gas bag (6).

2. The rapid detection device for soluble chloride ion concentration in coal according to claim 1, characterized in that: The piston mixer (7) comprises a measuring cylinder with an upper opening, wherein a piston is provided in the measuring cylinder and moves in contact with the inner wall of the measuring cylinder, and a closed cavity can be formed between the piston and the measuring cylinder; an air inlet pipe connected to the air bag (6) is provided at the bottom of the measuring cylinder, and an electric valve a is provided on the air inlet pipe; a liquid inlet pipe is provided on the side of the measuring cylinder, and an electric valve b is provided on the liquid inlet pipe; an air outlet pipe is also provided on the piston, and an electric valve c is provided on the air outlet pipe.

3. The rapid detection device for soluble chloride ion concentration in coal according to claim 1, characterized in that: The anode of the electrolysis device is made of carbon material with adsorption function, the cathode is made of metal material, and the voltage applied to each set of anode and cathode plates is greater than 3V.

4. The rapid detection device for soluble chloride ion concentration in coal according to claim 1, characterized in that: The electrolysis device has a 180° inversion function, and the aqueous solution in the electrolysis cell flows back and forth under the action of gravity.

5. The rapid detection device for soluble chloride ion concentration in coal according to claim 1, characterized in that: The sampling points of the automatic sampling machine (1) are distributed as follows: the sampling method along the transverse section and the longitudinal section of the coal transport carriage is three-point type, the first point is vertically downward, the second point is inclined 45-60 degrees to the left and deep into the inner wall of the carriage, and the third point is inclined 45-60 degrees to the right and deep into the inner wall of the carriage.

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