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Acid gas treatment method

A technology of acid gas and treatment method, which is applied in the direction of separation method, chemical instrument and method, dispersed particle filtration, etc., can solve the problems of labor need, poor acid gas treatment, and poor acid gas concentration measurement, so as to reduce excessive addition and improve Dealing with bad effects

Active Publication Date: 2016-09-28
KURITA WATER INDUSTRIES LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, as a heavy metal treatment method, it is usually a method of insolubilization treatment using a chelate such as diethyldithiocarbamate. Although the heavy metal immobilization effect is high in a short period of time, the following problems remain: The pH drop caused by acid rain and the oxidation and self-decomposition of chelates lead to the dissolution of heavy metals such as lead
[0013] However, in Patent Document 1, although it is possible to cope with an unexpected situation at the entrance to a certain extent, it does not take into account the measurement delay of the measuring device, and cannot cope with the delay in the addition of alkali agent caused by the measurement delay. Poor treatment of acid gas caused by
Furthermore, in Patent Document 2 and Patent Document 3, the measurement environment of the flue before dust collection has a higher acid gas concentration and higher temperature than the measurement environment after dust collection, and it is necessary to seek measures against corrosion of the measurement equipment materials.
In addition, since there is a large amount of coal dust in the exhaust gas before dust removal, dust removal measures are required, and labor is required for maintenance such as replacement of dust removal filters
In addition, since the measurement signal of the acid gas concentration has a direct influence on the addition amount of the alkali agent, measurement failure due to failure of these measurement devices becomes a major problem in stably managing the acid gas concentration at the outlet.

Method used

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Examples

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example

[0101] Describe the simulated reaction system.

[0102] [Simulation reaction system]: Compound reaction on exhaust and bag filter

[0103] In the simulated reaction system, the reaction of sodium bicarbonate powder and hydrogen chloride (HCL) includes the following two reactions: the instantaneous reaction in the exhaust, and the unreacted sodium bicarbonate powder accumulated on the bag filter Reaction with HCL (reference figure 2 ). In addition, the retention time of the captured material in the bag filter is usually about 2 hours. Therefore, in this simulation, it is assumed that the fine sodium bicarbonate powder on the bag filter disappears within a predetermined time (set to about 2 hours).

[0104] Reference figure 2 , Explain the basic structure of the simulated reaction system.

[0105] First, in the dosing control in the incinerator, the HCl concentration is measured by the ion electrode type HCl concentration measurement device (low speed) installed at the outlet of the...

example 1～ example 5

[0208] In the above simulation, feedback control is performed by adding the following two additive outputs: Based on the HCl concentration measured by the HCl concentration measurement device (low speed) 14 (the measurement delay time of the measurement device is 9.5 minutes in total), The PID control method "P (proportional gain) = 100%, I = 0.1 seconds, D = 0.1 seconds, the lower limit of the additive amount output is 200 kg / h, and the upper limit of the additive amount output is 480 kg / h." The value (SV) is set to 200ppm and feedback control is performed for the additive output; and based on the HCl concentration measured by the HCl concentration measuring device (high speed) 15, the outlet control target value (SV) is set to the same setting 200ppm and added output with feedback control.

[0209] Furthermore, the measurement delay time of the HCl concentration measurement device (high speed) 15 is 2 seconds in Example 1, 1 minute in Example 2, 3 minutes in Example 3, and 5 mi...

example 6

[0215] In the simulation described above, a 50% output limit is imposed on the addition output that is feedback-controlled based on the HCl concentration measured by the HCl concentration measurement device (low speed) 14 (the measurement delay time of the measurement device is 9.5 minutes), and The addition output is feedback-controlled based on the HCl concentration measured by the HCl concentration measurement device (high speed) 15 (the measurement delay time of the measurement device is 2 seconds). There is no limit (100%), and the two addition outputs are Add them for feedback control.

[0216] Table 1 shows the addition amount of sodium bicarbonate powder and the HCl concentration at the outlet of the bag filter after treatment with sodium bicarbonate powder. In addition, the change in the amount of sodium bicarbonate powder added during the control and the HCl concentration at the outlet of the bag filter is shown in Figure 16 .

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Abstract

The invention aims at providing a treatment method of acid gas. The treatment method is capable of solving the problems of poor treatment of the acid gas and excessive addition of an alkaline agent caused by measuring delay of conventional feedback control in a feedback form of controlling the additive amount of the alkaline agent according to measured signals of acid gas concentration. The treatment method of the acid gas is characterized in that the alkaline agent is added in combustion exhaust containing the acid gas, and the feedback control is carried out for the additive amount of the alkaline agent according to measured signals of acid gas concentration measuring machines which are configured to measure acid gas concentration after dust is collected. The treatment method comprises the steps of measuring the concentration of the same kind of acid gas through an HCI concentration measuring machine (low speed) (14) and an HCI concentration measuring machine (high speed) (15), the measuring delay times of the HCI concentration measuring machine (low speed) and the HCI concentration measuring machine (high speed) being different from each other; and calculating the output value of the additive amount of the alkaline agent through feedback operation according to the measured signals of a plurality of acid gas concentration measuring machines.

Description

Technical field [0001] The invention relates to a method for treating harmful acid gases such as hydrogen chloride or sulfur oxides generated in combustion equipment such as municipal waste incinerators, industrial waste incinerators, power boilers, carbonization furnaces, and private factories. In detail, the present invention relates to a method for efficiently controlling the addition amount of an alkali agent for treating acid gas. Background technique [0002] Exhaust gas containing harmful hydrogen chloride or sulfur oxides is treated with alkali agents such as slaked lime or sodium bicarbonate, then dust is removed by dust collectors such as bag filters (BF), and then discharged from the chimney. On the other hand, the fly ash collected by the dust collector contains harmful heavy metals such as Pb and Cd, and these harmful heavy metals are stabilized and then landfilled. [0003] Sodium bicarbonate processed into fine powder of 5 μm to 30 μm has higher reactivity than slak...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D53/82B01D53/50B01D53/68G05B13/00
CPCB01D46/00B01D53/14B01D53/30B01D53/40B01D53/74
Inventor 益子光博
Owner KURITA WATER INDUSTRIES LTD