JPH0358765B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a removal device that dry-type removes air pollutants (SOx, NOx, soot, etc.) contained in flue gas from boilers and the like.

[Conventional technology]

In equipment that desulfurizes and denitrates flue gas in a dry manner and contains a high concentration of soot and dust, such as in a coal boiler, soot and dust accumulates between the grains of the granular desulfurization and denitrification agent (hereinafter referred to as the remover). , ventilation of flue gas is obstructed, pressure loss increases, and ventilation becomes impossible.

In the method of reusing the remover after desulfurization and denitrification, the absorption capacity of the remover is sacrificed a little, and the cycle time of use → regeneration → use is shortened, so that the remover can be recycled without significantly impairing economic efficiency. It is possible to reduce clogging caused by soot and dust.

However, if the removal agent chemically reacts with sulfur oxides (SOx) or nitrogen oxides (NOx) and reuse is impossible, there is sufficient removal ability due to clogging caused by soot and dust in the flue gas. It is necessary to replace the entire removal agent including the removal agent, which is extremely uneconomical.

In a fixed bed removal device using a granular removal agent, soot and dust in flue gas is collected most densely near the gas flow entrance of the fixed bed, and becomes coarser as the distance from the entrance increases. become. Figure 2 shows a typical example of the dust distribution in the fixed bed. Further, in a desulfurization test using a fixed bed, a typical example of the relationship between the elapsed time, the pressure loss of the removal device, and the desulfurization efficiency is shown in FIG. In this way, in the fixed bed, the activity of the removal agent is lost from the part close to the gas inlet, the pressure loss increases as time passes, and the removal efficiency also decreases, making it difficult to perform a steady removal process. There were flaws.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the above-mentioned fixed layer removing apparatus and to provide a removing apparatus capable of performing a constant removal process with high efficiency.

[Means for solving problems]

The present invention provides (1) a dry flue gas treatment device using particulate matter as a remover for air pollutants in flue gas, (a) providing n moving layers made of the particulate matter; ) The moving direction of each moving layer and the flow direction of flue gas to be removed are not parallel; (c) In the same moving layer, it is parallel to the flow direction of flue gas including any point in the moving layer. The areas A of the cross sections are the same, and the lengths l of the cross sections in the flow direction of the flue gas are the same, and (d) the moving layers are arranged in the order in which the flue gas passes through M ₁ ,
When M ₂ ,...,Mn, M ₁ , M ₂ ,...,
The relationship between the areas A ₁ , A ₂ , ..., An of the above cross section of Mn and the above lengths l ₁ , l ₂ , ..., ln is A ₁ <A ₂ ...<An l ₁ <l ₂ ...<ln (e) The linear velocity at which the moving layers M ₁ , M ₂ ,..., Mn move
A relationship such as V ₁ > V _{2 … > Vn is established between V 1 , V 2 , …} , Vn, and (f) the particulate matter in the moving layer is transferred from Mn to M _o-1 on the upstream side of the flue gas, ..., _M2 , _M1 , and (d) the transferring means includes means for sieving particulate matter.

The present invention will be explained using the drawings.

FIG. 1 is a diagram showing an example of the present invention, in which two particulate matter moving layers are provided horizontally adjacent to each other, the gas flow is horizontal, the particulate matter in the moving layer is moved vertically, and the gas flow is The thickness of the moving layer in the direction indicates that the layer M ₁ into which the gas first enters is thinner than the next layer M ₂ . The direction of movement of the moving layer and the direction of flow of flue gas do not need to be parallel, and do not need to be perpendicular to each other.
Structurally, it is preferable that they be orthogonal. Furthermore, a sieve means 10 is provided for removing soot and dust adhering to the granular material when moving the granular material from _M2 to _M1 . The operating conditions of this device are as follows.
The flow of the gas to be treated is indicated by a horizontal arrow and enters the moving bed M ₁ from the gas inlet 1 of the device. Now in contact with the granular remover layer of thickness l ₁ , then the transfer layer
It flows into M ₂ , contacts a granular removing agent layer with a thickness of l ₂ , and is discharged from the gas outlet 2 of the device. In M ₁ , the concentration of soot and dust in the materials to be removed in the inflow gas is high, so by increasing the movement speed of the removal agent and shortening the residence time of soot and dust, clogging between grains of soot and dust is reduced. , _M1 suppresses the increase in pressure loss. In M ₂ , M ₁
Since the dust is removed by the exhaust gas, the concentration of soot and dust in the flue gas is low, and pressure loss does not pose a problem.

The flow of the removing agent is vertical and indicated by an arrow; it is first charged from the removing agent inlet 8 at the top of the moving bed to form a moving bed M ₂ with a thickness of l ₂ , and then flows through the flow regulating means 9 provided at the lower outlet. Once taken out through the sieve means 10
Then, the dust or inert substances covering the surface of the removal agent are mechanically separated and conveyed, for example by a bucket conveyor, to the upper inlet 6 of M ₁ , forming a moving layer M ₁ with a thickness l ₁ and passing downwards. The liquid is taken out through a flow rate regulating means 7 provided at the outlet. flow rate adjustment means 9;
7 is, for example, a rotary valve that adjusts the flow rates of the removing agent in the two moving layers. In this case, the moving layer
If the linear velocities of M ₁ and M ₂ are V ₁ and V ₂ , then
Maintain the relationship V ₁ > V ₂ . The thickness of the moving bed is maintained by screens 5 on the gas inlet and outlet faces of the bed.

In this device, the particulate matter transfer means is equipped with a sieve means, so dust or inert substances mixed in the particulate matter or covering the surface are removed, improving the dust removal efficiency in the next moving layer and contaminants. The removal efficiency is improved and pressure loss is reduced. Furthermore, it is also possible to extract and replenish particulate matter for each layer.

Therefore, by providing the sieve means,
Optimal operation of this device becomes possible.

In the device of the present invention, the number n of moving layers, the distribution of the thickness l of each layer, the cross-sectional area of the moving layer perpendicular to the direction of gas flow, etc. Determined by the type and amount of the substance, the performance of the remover, etc.

Examples will be described below.

〔Example〕

Flue gas treatment was carried out using the apparatus shown in FIG. 1 in which the number of moving layers (n) was 2.

Thickness of moving layer: l ₁ = 0.4 m l ₂ = 1.4 m Cross-sectional area of moving layer: A ₁ = 2.0 m ² A ₂ = 7.0 m ² Processing gas and flow rate: Coal boiler exhaust gas
50000Nm ³ /H Substances and concentrations to be removed: Soot and dust
300-400mg/Nm ³ SO ₂ 350-450ppm Shape and size of remover: Spherical 3-10mm in diameter Flow rate of remover: 380Kg/H Linear velocity of moving bed: V ₁ = 0.25m/H V ₂ = 0.08m /H Under the conditions above, pressure loss of less than 1500 mmAq and desulfurization efficiency of 90% continued steadily.

〔Effect of the invention〕

As described in detail above, according to the apparatus of the present invention, highly efficient and steady removal processing can be performed, and it greatly contributes to air pollution prevention technology.

[Brief explanation of drawings]

FIG. 1 shows an example of the apparatus of the present invention, in which a is a plan view thereof and b is a schematic elevational view showing the operating status of the apparatus. Figures 2 and 3 are graphs showing the distribution of soot and dust in the fixed bed and the operational results. DESCRIPTION OF SYMBOLS 1...Gas inlet, 2...Gas outlet, 5...Screen, 6, 8...Removal agent inlet, 7, 9...Flow rate adjustment means, 10...Sieve means, _M1 , _M2 ...Movement Layer, l ₁ , l ₂ ...thickness of the moving layer.

Claims (1)

[Scope of Claims] 1. In a dry flue gas treatment device using particulate matter as a remover for air pollutants in flue gas, (a) providing n moving layers made of the particulate matter; ) The moving direction of each moving layer and the flow direction of flue gas to be removed are not parallel; (c) In the same moving layer, it is parallel to the flow direction of flue gas including any point in the moving layer. The areas A of the cross sections are the same, and the lengths l of the cross sections in the flow direction of the flue gas are the same, and (d) the moving layers are arranged as M ₁ , M ₂ ,
..., Mn, the area of the above cross section of M ₁ , M ₂ , ..., Mn is A ₁ , A ₂ , ..., An and the above length l ₁ ,
A relationship such as A ₁ <A ₂ ...<An l ₁ <l ₂ ...<ln is established between l ₂ ,..., ln, and (e) the line on which the moving layers M ₁ , M ₂ ,..., Mn move speed
A relationship such as V ₁ > V ₂ … > Vn is established between V ₁ , V ₂ , …, Vn, and (f) particulate matter in the moving layer is transferred from Mn to Mn _-1 , … on the upstream side of the flue gas. , M ₂ , M ₁ , and (d) the transferring means includes means for sieving particulate matter.