JPS60193523A - Desulfurizing apparatus for exhaust gas - Google Patents

Abstract

PURPOSE:To follow-up and control the circulating amount of liquid for desulfurization for load variation continuously nd automatically by providing a movable blade type circulation pump of liquid for desulfurization and variably controlling the movable blade with variable control means in accordance with load variation of treatment gas quantities or the like. CONSTITUTION:The circulating amount Q of liquid for desulfurization is continuously changed by selecting and controlling the operation number of a pump in accordance with gaseous system in a desulfurizing apparatus for an exhaust gas, and also variably controlling the movable blade mechanism 6a, 6b of the selected pumps in accordance with load variation of change in the flow rate of said exhaust gas. By this method, broad load follow-up is made possible with a small number of pump and the flow rate of liquid for desulfurization fed to a desulfurization tower 1 can be continuously changed and also the slurry is prevented from accumulating in a pipeline and the operation efficiency can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust gas desulfurization apparatus, and more particularly to improvements in the configuration of a desulfurization liquid circulation system and its control means.

FIG. 1 is a diagram showing a schematic configuration of a conventional exhaust gas desulfurization device. In FIG. 1, reference numeral 1 denotes a desulfurization tower, which desulfurizes exhaust gas introduced from an upper inlet 1a and then leads it out to the outside from a lower outlet 1b. Desulfurization liquid (not shown) is stored in the desulfurization tower 1, and this desulfurization liquid is supplied from a plurality of, for example, four centrifugal circulation pumps 2a, 2b, 2c, and 2cN.
7-117) The liquid is pumped up to the upper part and injected into the tower 1.

Note that all of the circulation pumps 2a to 2d use fixed blades.

By the way, nitrous chloride in the exhaust gas in the desulfurization tower 1
The absorption rate of III gas depends on the properties of the desulfurization liquid (mainly PH)
This is influenced by the contact I1m between the desulfurization liquid and the exhaust gas. Therefore, if the process gas volume (which is controlled by the desulfurization ventilator in response to the boiler load signal) increases or decreases,
It is necessary to variably control the sulfur dioxide gas absorption rate within the tower 1. For this purpose, the properties of the desulfurization liquid should be controlled by the amount of sulfur dioxide gas absorbent added, or the circulation pumps 2a to 2d should be used to increase the frequency of contact between the desulfurization liquid and the exhaust gas.
It is necessary to control the circulation amount Q of the 12-sulfur liquid.

Conventionally, means for changing the circulation IQ of the desulfurization liquid and -
Thus, the number of operating pumps 2a to 2d is variably controlled according to the required circulation amount.

In the conventional equipment with the above configuration, as shown in Fig. 2, the circulation amount Q of the desulfurization liquid changes in stages according to the number of pumps in operation, which has the disadvantage that continuous load tracking cannot be performed. there were. In other words, there was a problem in that fine-grained circulation volume control could not be performed in response to load fluctuations. In particular, when the exhaust gas desulfurization equipment becomes larger, the circulation amount Q also increases, so conventional pumps have limitations in terms of structure and performance, and also have problems in terms of energy loss.

The present invention was made based on these circumstances,
The purpose of this is to enable continuous automatic follow-up control Il'1j of the liquid system in response to load fluctuations in the gas system, to perform fine-grained and highly accurate circulation volume control of the desulfurization liquid, and to improve energy efficiency. Another object of the present invention is to provide a preferable exhaust gas desulfurization device.

In order to achieve the above object, the present invention is characterized by the following configuration. In other words, a movable vane type circulation pump is provided in the exhaust gas desulfurization equipment main body, and the movable vanes of this pump are variably controlled by a variable control means in accordance with load fluctuations of the process gas, etc., thereby controlling the amount of desulfurization liquid circulated. It is characterized by continuous automatic tracking control in response to fluctuations.

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 3 and 4 are a configuration diagram of an embodiment of the present invention and a circulation amount characteristic diagram of the desulfurization liquid, respectively, corresponding to FIGS. 1 and 2. In FIG. 3, the same parts as in FIG. 1 are given the same reference numerals and detailed explanations are omitted. In FIG. 3, 3a.

3b is a circulation pump adjustment signal generator that generates a circulation pump adjustment signal in response to load fluctuations, etc., and signals from these signal generators 3a, 3b are given to electric mechanisms 4a, 4b. The electric mechanisms 48 and 4b drive the movable vane mechanisms 6a and 6b of the movable vane circulation pumps 5a and 5b provided in the main body of the exhaust gas desulfurizer 1A11 in accordance with the adjustment signal.

Thus, according to this embodiment with the above configuration, in correspondence with the gas system, the number of pumps in operation is selectively controlled by a control system (not shown), and the movable II mechanisms 6a, 6 of the selected pumps are controlled.
By variably controlling b in accordance with load fluctuations, it is possible to continuously change the circulation amount Q of the desulfurizing liquid as shown by the solid line in Figure 4, and it is possible to follow a wide range of loads with a small number of pumps. It becomes possible. In particular, by simultaneously changing the movable blades of a plurality of circulation pumps 5a and 5b in response to changes in the exhaust gas flow rate, the flow rate of the desulfurizing liquid to the tower 1 can be changed steplessly between points A and B. ,
Prevents slurry from accumulating in piping. Furthermore, the pump operation efficiency can be increased, increasing the energy saving effect.

FIG. 5 is a diagram showing another embodiment of the present invention in which an absorbent injection control system is added to the circulation amount control system shown in FIG. 3. ′
In the IR5 diagram, 10 is a computer that runs at least a simulation program 11. Load following control program 12. It is equipped with such things as The simulation program 11 includes processing gas MS1. SO2 concentration 82. Data such as the movable purchase variable amount 83 and the properties (PH) 84 of the desulfurization liquid are given, and a predicted value of the desulfurization rate is calculated. The load follow-up control program 12 is given a signal S5 indicating the desulfurization rate predicted value calculated by the simulation program 11 and a boiler load signal S6 given from the outside as target values. In this way, the program 12 performs the normal estimation of liquid components, and outputs the optimal circulation amount control command S7 and the optimal absorbent injection control command s8 corresponding to the liquid components when the load increases. The above control command s7 is the circulation amount control system 1
3, and the same movable wing control as described above is performed.

In addition, the above control command s8 is the absorbent injection 11+1III system 1.
4, and the absorption control is performed digitally.

Thus, in this embodiment with the above configuration, the desulfurization tower 1
The circulation rate of the desulfurizing liquid to the exhaust gas is adjusted by variable control of the movable vane circulation pump in response to changes in the flow rate of the exhaust gas, so smooth flow control can be performed automatically as in the previous embodiment. , it is possible to perform desulfurization control with higher precision than conventional methods.

In addition, the operation efficiency of the pump is further increased by cooperation with the absorbent injection control system 14, and the efficiency is improved by 10% or more compared to the conventional system, and the starting torque of the pump is reduced. In addition, it becomes easier to deal with headroom margins, and the equipment can be made more compact.

Therefore, it is advantageous for increasing the size of the desulfurization equipment. Moreover, automatic control by the air filter 10 enables continuous circulation volume control in coordination with the gas system, allows for relatively free combinations with absorbent injection, and enables optimal operation that takes into account energy-saving measures. becomes.

As detailed above, according to the present invention, a movable vane type circulation pump is provided in the main body of the exhaust gas desulfurization apparatus, and the movable vanes of this pump are variably controlled by the variable control means in accordance with load fluctuations such as the amount of processed gas. As a result, the desulfurization liquid circulation amount is continuously and automatically controlled in response to load fluctuations, making it possible to continuously and automatically control the liquid system in response to load fluctuations in the gas system. It is possible to provide an exhaust gas desulfurization device that not only can perform fine and highly accurate circulation rate control but also is preferable from an energy saving perspective.

[Brief explanation of the drawing]

Figures 1 and 2 are a schematic diagram of a conventional exhaust gas desulfurization device and a characteristic diagram of the circulation amount of desulfurization liquid, and Figures 3 and 4 are illustrations of a book corresponding to Figures 1 and 2. A configuration diagram of an embodiment of the invention and a circulation ω characteristic diagram of a desulfurizing liquid. FIG. 5 is a block diagram showing the configuration of another practical example of the invention. DESCRIPTION OF SYMBOLS 1... Desulfurization tower, 2a to 2d... Centrifugal fixed vane circulation pump, 3a, 3b... Circulation pump adjustment signal generator, 4a, 4b... Electric mechanism, 5a, 5b... Movable Airfoil circulation pump, 10... Computer, 13...
14. Absorbent injection control system. Applicant Sub-Agent Patent Attorney Takehiko Suzue

Claims (1)

[Claims] The main body of the exhaust gas desulfurization equipment includes a movable vane type circulation pump installed in the main body to circulate the desulfurization liquid, and a movable vane of the circulation pump to be variably controlled according to load fluctuations such as the amount of gas to be processed. An exhaust gas desulfurization apparatus, characterized in that the circulation m of the desulfurization liquid is continuously and automatically controlled to follow changes in load.