CN-122006451-A - Method and system for measuring and removing chromium in sintering flue gas

CN122006451ACN 122006451 ACN122006451 ACN 122006451ACN-122006451-A

Abstract

The invention relates to the technical field of sintering flue gas detection, in particular to a method and a system for measuring and removing chromium in sintering flue gas, which comprise the steps of adopting deionized water and a high-grade pure medicine to prepare a mixed solution with 2% -8% + KOH concentration and 1% -4% NaOH concentration as absorption liquid, adding the mixed solution into each absorption tank, connecting equipment for absorbing the flue gas, automatically controlling the operation of a bypass pipeline flue gas supercharging device through a real-time feedback signal obtained by an air pressure sensing device in the absorption tank, automatically measuring the flue gas flow in a flue gas outlet bypass pipeline in real time by a flow automatic control device, automatically controlling a flue gas inlet bypass pipeline valve and a flue gas outlet bypass pipeline valve according to pressure and flow values read by the air pressure sensing device and the flow automatic control device of each bypass through an automatic control program, detecting and analyzing the result of the absorption liquid, ensuring that chromium in the flue gas is absorbed by the absorption liquid more thoroughly, and ensuring that the measurement result of chromium in the flue gas is more accurate.

Inventors

QIAN FENG
JIAO LINLIN
HOU HONGYU
ZHANG MINGZHOU
SONG SHIZHE
MA GUANGYU
XU PENGFEI
ZHANG YONG
DENG JUNHUA
WU MENG

Assignees

鞍钢股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260312

Claims (10)

1. The method for measuring and removing chromium in sintering flue gas is characterized by comprising the following steps: S1, preparing an absorption liquid: preparing a mixed solution with NaOH concentration of 2% -8% + and KOH concentration of 1% -4% by adopting deionized water and a high-grade pure medicine as an absorption liquid, and adding the prepared absorption liquid into each absorption tank; s2, connecting a flue gas absorption device; s3, on-line absorption of chromium in the flue gas through flue gas absorption equipment; S4, detecting an absorption liquid and analyzing the result: after the online absorption of the flue gas of the section to be detected is completed, the total flow of the flue gas of the whole section to be detected is recorded as V and L by a gas flowmeter, the total volume of the absorption liquid is measured and is recorded as Q and mL by the unit, and after the volume is measured, the absorption liquid is introduced into liquid component analysis equipment to measure the TCr concentration of the absorption liquid and is recorded as W and μg/mL by the unit; Calculating the chromium content X in the flue gas, wherein X is calculated by Cr 2 O 3 to obtain a final result: ; X units μg/m 3 .
2. The method for measuring and removing chromium in sintering flue gas according to claim 1, wherein the equipment for connecting flue gas absorption is characterized in that N flue gas inlet branch pipelines are connected to a flue gas inlet main pipeline, each flue gas inlet branch pipeline is respectively connected with a flue gas inlet branch pipeline valve and a branch pipeline flue gas supercharging device, the tail end of each flue gas inlet branch pipeline is respectively connected with an absorption tank, each absorption tank is respectively connected with an absorption tank air pressure sensing device and a liquid level meter, each absorption tank is respectively provided with an absorption tank liquid inlet valve and an absorption tank liquid discharging valve, the other end of each absorption tank is respectively connected with a flue gas outlet branch pipeline, each flue gas outlet branch pipeline is respectively connected with a flue gas outlet branch pipeline valve and a flow automatic control device, and the N flue gas outlet branch pipelines are converged together and are jointly connected with the flue gas outlet main pipeline.
3. The method for removing chromium from sintering flue gas according to claim 1, wherein the absorption liquid prepared in step S1 is added to each absorption tank at a position not lower than 1/2 of the tank height.
4. The method for measuring and removing chromium in sintering flue gas according to claim 2, wherein the online absorption of chromium in the flue gas by the flue gas absorption device is realized by automatically controlling the operation of a bypass pipeline flue gas supercharging device by a real-time feedback signal obtained by an air pressure sensing device in an absorption tank, and the automatic flow control device is used for measuring the flue gas flow in a flue gas outlet bypass pipeline in real time and automatically controlling the flow, and the flue gas inlet bypass pipeline valve and the flue gas outlet bypass pipeline valve are automatically controlled by an automatic control program according to the pressure and flow values read by the air pressure sensing device and the automatic flow control device of each bypass, and specifically comprises the following steps: S3.1, in the air charging process, an air inlet valve of a1 st smoke air inlet branch pipeline above is controlled by a valve automatic control program, an air outlet valve of the branch pipeline is in a closed state, air inlet valves and air outlet valves of other branch pipelines are in closed states, smoke enters an absorption tank corresponding to the branch from the 1 st smoke air inlet branch pipeline above in the state, the air pressure in the absorption tank is gradually increased through a branch pipeline smoke supercharging device, the air pressure values before and after supercharging are measured in real time through an air pressure sensing device in the absorption tank, the initial pressure is recorded as P0, when the measured air pressure reaches 50-200 KPa, the automatic control program of the valve receives a signal sent by the air pressure sensing device, and automatically closes the air inlet valve of the 1 st smoke air inlet branch pipeline, and simultaneously opens the air inlet valve of the 2 nd smoke air inlet branch pipeline, so as to complete the air charging process of the 1 st smoke air inlet branch pipeline; s3.2, an oscillation absorption process, namely after the inflation process of each smoke gas inlet branch pipeline is completed, automatically starting an absorption program, and oscillating the branch absorption tank up and down in a reciprocating manner; And S3.3, in the air discharging process, the air discharging process is controlled by an automatic control program of a valve as in the air charging process, along with the sequential air charging process of the N smoke gas inlet branch pipelines, when the N-1 th branch starts the air charging process, the absorption tank oscillating system stops the oscillation of the 1 st branch absorption tank, the valve automatic control program automatically opens the 1 st smoke gas outlet branch pipeline valve, the smoke gas flow is regulated to be the same as the smoke gas inlet main pipeline through the flow automatic control device of the branch, in the process, the air discharging process of the 1 st branch absorption tank is measured by the air pressure sensing device, when the air pressure of the absorption tank is reduced to P0 again, the air discharging process of the 1 st branch pipeline is completed, at the moment, the absorption tank oscillating system stops the oscillation of the 2 nd branch absorption tank, the valve automatic control program automatically closes the 1 st smoke gas outlet branch pipeline valve, simultaneously automatically opens the 2 nd branch pipeline valve, the air discharging process of the 2 nd branch pipeline is started, and the air discharging process of the N smoke gas inlet branch pipelines is sequentially completed, and the air discharging process of the N branch pipelines is recycled from the 1 st branch pipeline.
5. The method for determining and removing chromium in sintering flue gas according to claim 4, wherein the absorption tank is oscillated up and down in a reciprocating manner, the vibration amplitude of the tank body of the absorption tank is 0.6-1 times the height of the tank body, and the vibration frequency is 120-180 times/min.
6. The method for removing chromium from sintering flue gas according to claim 4, wherein the gas flowmeter is disposed on the main flue gas intake pipe.
7. The method for removing chromium from sintering flue gas according to claim 4, wherein the total volume of the absorption liquid is measured by opening a drain valve of each absorption tank to drain all the absorption liquid in each absorption tank into an absorption liquid drain tank.
8. The method for determining and removing chromium in sintering flue gas according to claim 1, wherein the range of N is 20-60.
9. A system for realizing the determination and removal of chromium in sintering flue gas according to any one of claims 1-8, which is characterized by comprising an absorption liquid feeding-discharging system, an automatic sintering flue gas absorption control system and an absorption tank oscillation system; The absorption liquid feeding-discharging system comprises an absorption liquid feeding groove, an absorption liquid discharging branch pipeline, an absorption liquid feeding main pipeline, an absorption liquid discharging main pipeline, an absorption liquid volume measuring device, an absorption liquid discharging groove, an absorption tank liquid inlet valve and an absorption tank liquid discharging valve, wherein the absorption liquid feeding groove is connected with a longitudinal absorption liquid feeding main pipeline, the absorption liquid feeding main pipeline is connected with N absorption liquid feeding branch pipelines in parallel connection, each absorption liquid feeding branch pipeline is respectively connected with an absorption tank through an absorption tank liquid inlet valve, each absorption tank liquid discharging valve on each absorption tank is respectively connected with an absorption liquid discharging branch pipeline, the N absorption liquid discharging branch pipelines are jointly connected with one absorption liquid discharging main pipeline according to the parallel connection, and the other end of the absorption liquid discharging main pipeline is connected with an absorption liquid discharging groove with the absorption liquid volume measuring device; the sintering flue gas absorption automatic control system comprises a flue gas inlet main pipeline, flue gas inlet branch pipeline valves, branch pipeline flue gas supercharging devices, absorption tank air pressure sensing devices, absorption tank liquid level meters, absorption tanks, flue gas outlet branch pipeline valves, flow automatic control devices, flue gas outlet main pipelines, flue gas inlet branch pipelines, flue gas outlet branch pipelines and gas flow meters, wherein the flue gas inlet main pipeline with the gas flow meters is connected with N parallel flue gas inlet branch pipelines, each flue gas inlet branch pipeline is provided with one flue gas inlet branch pipeline valve and one branch pipeline flue gas supercharging device, the other end of each flue gas inlet branch pipeline is respectively connected to the top of one absorption tank, each absorption tank is internally connected with one absorption tank air pressure sensing device and one absorption tank liquid level meter, the outside is respectively connected with one absorption tank drain valve and one absorption tank liquid inlet valve, the top of each absorption tank is also respectively connected with one flue gas outlet branch pipeline, one end of each flue gas outlet branch pipeline, which is close to the absorption tank, is respectively provided with one flow automatic control device, the other end of each flue gas outlet branch pipeline is respectively provided with one flue gas outlet branch pipeline valve, and the N outlet branch pipelines are connected to the flue gas outlet branch pipelines in a common connection mode according to the parallel flue gas outlet branch pipeline; The absorption tank oscillation system comprises an absorption tank oscillation device fixing frame and absorption tank oscillation cantilevers, wherein the absorption tank oscillation device fixing frame is connected with N absorption tank oscillation cantilevers which are longitudinally arranged, the absorption tank oscillation cantilevers are connected with the absorption tank oscillation device fixing frame through a slideway, each absorption tank can independently reciprocate along the vertical direction, and each absorption tank oscillation cantilever is connected with one absorption tank respectively.
10. The system for determining and removing chromium from sintering flue gas according to claim 9, wherein the absorption liquid feeding-discharging system, the absorption tank air pressure sensing device and the absorption tank liquid level meter are made of acid and alkali corrosion resistant materials; The absorption tank, the flue gas inlet branch pipeline and the flue gas outlet branch pipeline are made of explosion-proof materials; The end of the flue gas inlet branch pipeline and the flue gas outlet branch pipeline, which is connected with the absorption tank, is manufactured by adopting a non-rigid hose.

Description

Method and system for measuring and removing chromium in sintering flue gas Technical Field The invention relates to the technical field of sintering flue gas detection, in particular to a method and a system for measuring and removing chromium in sintering flue gas. Background The national strict supervision is carried out on the discharge disposal of dangerous wastes, and the dangerous wastes are required to be delivered to qualified enterprises for centralized disposal according to regulations. According to the national hazardous waste identification standard, some chromium-containing wastes of steel enterprises belong to hazardous wastes, the classification number of the national hazardous waste is HW17 in the directory of the national hazardous wastes, and the common valence trivalent chromium and hexavalent chromium of the chromium belong to toxic substances, especially hexavalent chromium has extremely high toxicity, and belong to carcinogens and mutagenic substances. In order to treat the hazardous wastes, some iron and steel enterprises subject the chromium-containing wastes to harmless treatment through a sintering process, so that a part of chromium elements in the wastes enter the atmosphere along with flue gas, and serious pollution is caused to the environment. In order to control the pollution of chromium in the flue gas to the environment, the research of the chromium content in the flue gas has important significance. After the sintering flue gas is treated by dust removal, desulfurization and denitrification processes, the content of chromium element in the flue gas is low, and the chromium element exists in a gas phase or tiny particle form. At present, a plurality of methods for detecting the chromium content in the solid and the liquid, such as an atomic absorption spectrometry, a spectrophotometry, a chromogenic method and the like, but the research on the method for detecting the chromium content in the discharged flue gas is less. In the prior art, patent application number 202210464227.6 discloses a method for analyzing total chromium content in sintering flue gas, which solves the problems of insufficient contact between flue gas to be tested and absorption liquid, short reaction time and inaccurate content analysis caused by poor absorption effect in the prior art, and adopts double gas storage bags to enable the flue gas to be tested to circulate for multiple times, while ensuring that chromium in the flue gas is completely absorbed, the method has the two defects that 1) because the chromium content in the sintering flue gas fluctuates in real time and fluctuates severely, the method only can circularly absorb a small section in the sintering flue gas for multiple times by adopting the gas storage bags, the detection result cannot completely represent the large-flow sintering flue gas, and 2) the adoption of the double gas storage bags for multiple circulation process needs longer time to influence the measurement efficiency. Patent application number 202210596994.2 discloses a system and a method for detecting Cr content in sintering flue gas, which solve the problem of inaccurate detection result caused by insufficient contact between flue gas to be detected and absorption liquid and short contact time in the prior art; the method adopts a special absorber structure, and can realize more thorough absorption of harmful elements in the flue gas, but has certain defects that the gas to be detected moves upwards from the bottom of the absorption liquid in the form of small bubbles, the contact is more sufficient, but the reaction time is shorter, the contact is almost instantaneous, the chromium in the flue gas can not be completely absorbed, and the measurement result is error. Disclosure of Invention The invention provides a method and a system for measuring and removing chromium in sintering flue gas, which ensure that chromium in the flue gas is absorbed by an absorption liquid more thoroughly, realize online removal of chromium in the flue gas while ensuring more accurate detection result, and have the characteristics of low cost, short time consumption and high efficiency without affecting flue gas emission and normal production. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme: a method for measuring and removing chromium in sintering flue gas comprises the following steps: S1, preparing an absorption liquid: preparing a mixed solution with NaOH concentration of 2% -8% + and KOH concentration of 1% -4% by adopting deionized water and a high-grade pure medicine as an absorption liquid, and adding the prepared absorption liquid into each absorption tank; s2, connecting a flue gas absorption device; s3, on-line absorption of chromium in the flue gas through flue gas absorption equipment; S4, detecting an absorption liquid and analyzing the result: after the online absorption of the flue gas of the section to be detecte