全部
  • 全部
  • 产品管理
  • 新闻资讯
  • 介绍内容
  • 企业网点
  • 常见问题
  • 企业视频
  • 企业图册
+
  • 华电吸收塔.jpg

CHEC absorption tower

key word:Heat exchange element


Product description

CHEC absorption tower

 

1. Introduction

1.1. Purpose

It is mainly used to absorb SO2 in flue gas.

1.2. Model meaning

                  16-(C21)- (A) -V(H)- 19. 2/4/3500

                   16 ------------------- diameter of absorption zone of absorption tower (m)

(C21) --------------- when there is "C + number", it means that the absorption tower is a conical tower. The "number" indicates the diameter of the bottom slurry tank (m); if there is no "C + number", it means that the absorption tower is a straight tower, and the diameter of the bottom slurry tank is equal to the diameter of the absorption zone of the absorption tower

                   (A)------------------- When there is "a", it means that there is a gas-liquid redistribution device in the absorption tower

                   V (H) --------------- V indicates that the flue gas outlet is arranged vertically; H indicates that the flue gas outlet is arranged horizontally

19.2 / 4 / 3500 ---- "number 1 / number 2 / Number 3", where "number 1" represents liquid gas ratio (L / m3); "number 2" refers to the number of spray layers; "number 3" refers to the volume of slurry tank of absorption tower (M3)

1.3. Structural features

The absorption tower is an empty spray tower with agitator, oxidation air system, spray layer, demister and anti-corrosion lining. There are four types of absorption tower: vertical tower side out type, cone tower side out type, vertical tower top out type and cone tower top out type. The absorption tower is a kind of empty tower without packing layer, which can prevent the components in the tower from scaling in structure design.

The absorption tower is divided into three main areas: the upper demist area, the middle spray area and the lower slurry area. There is a two-stage mist eliminator at the top of absorption tower. The first stage demister removes the large drops of liquid and smoke in the air flow; the second stage removes the small droplets after the first stage. The central spray zone is the main reaction absorption zone of the whole desulfurization system, and its range is from the upper spray layer to the liquid level of slurry pool. The main role of the lower slurry zone is to ensure that the circulating slurry stays in the slurry tank for a certain period of time to complete the sufficient chemical reaction; the second is to fully oxidize the calcium sulfite produced by the chemical reaction, so that the calcium sulfite can be completely converted into gypsum. The oxidation air pipe and agitator are arranged in the slurry tank. The oxidation air is forced to blow by the oxidation fan to ensure that calcium sulfite is completely converted into gypsum; the agitator is evenly arranged around the slurry tank to ensure the full mixing of slurry.

The whole absorption reaction mainly occurs in the spray area and slurry area to remove SO2 in the flue gas, so as to achieve the desulfurization efficiency and pollutant emission standards.

The liquid phase redistribution device (alrd) can be set in the absorption zone of the absorption tower to make the slurry flowing along the tower wall re suspend in the flue gas, and improve the gas-liquid contact near the inner wall of the tower. Under the same process conditions, the liquid gas ratio of alrd can be about 20% lower than the conventional design value, so as to reduce the operation cost.

The shell and bottom of absorption tower are welded with carbon steel plate to prevent leakage. The bare body is designed to withstand pressure loads, pipe forces and moments, wind loads and seismic loads, and all loads attached to the absorber. The support, reinforcement and anchor bolt of absorption tower can prevent the tower from tilting and shaking. The arched drain hole on the bottom of the tower can completely drain the slurry.

The design life of absorption tower is 30 years. The inner wall and bottom of the whole tower are lined with high-quality scale resin lining with corrosion resistance, wear resistance and impact resistance. C-276, a high nickel base alloy material, is used in the flue gas inlet section and the key parts in the tower to withstand the impact. The high temperature resistance, corrosion resistance and strength of the material are good.

The slurry circulating pipe in the absorption tower is made of corrosion-resistant FRP material.

All components in the absorption tower can withstand the impact of the maximum inlet air flow and the maximum inlet flue gas temperature, and the sufficient strength and corrosion allowance are considered for the tower structure and all components.

The absorption tower is also equipped with spray system inside the tower, demister and other necessary lifting measures for maintenance, as well as platforms, escalators and thermal insulation facilities outside the tower.

1.4. Working principle

The absorption tower uses the slurry containing calcium carbonate with pH value of 5.2-6.0 to remove sulfur dioxide from flue gas. The slurry tank of absorption tower shall be designed with sufficient residence time and sufficient mixing time to ensure the optimal utilization rate of limestone and crystallization of gypsum.

When the absorption liquid is atomized into the flue gas through the nozzle, the absorption liquid is dispersed into small droplets and covers the whole section of the absorption tower. When contacting with the flue gas countercurrent, SO2 in these droplets is absorbed. In this way, SO2 is absorbed in the absorption zone, and the oxidation and neutralization of the absorbent are completed in the slurry tank area at the bottom of the absorber, and finally gypsum is formed.

 

2. Main technical parameters

The main technical parameters of absorption tower are shown in table 3-1

Table 3-1 main technical parameters of absorption tower

Performance parameter Remarks
 SO2 concentration at absorber inletmg/m3 Standard state, dry basis, 6% oxygen
Flue gas flow at absorber inlet m3/h Actual flow
Flue gas flow at absorber outletm3/h Actual flow
Liquid gas ratio of absorption towerL/ m3 Total amount of slurry circulation / flue gas volume at absorber outlet
Spray layer number (layers) ———————
Flue gas velocity m/s ———————
Flue gas residence times Distance from top of flue gas inlet of absorber to top spray layer / flue gas velocity
Slurry concentration of absorption tower% Usually 15% or 20%

 

3. Selection method

CHEC adopts computer to simulate the desulfurization system and select the type of desulfurization system; the absorption tower design by computer can meet the requirements of users to the maximum extent.

If the user wishes to adopt the general contracting of Huadian absorption tower or client station desulfurization project, it shall provide performance guarantee, atmospheric conditions, water quality conditions, limestone quality, coal quality data, FGD inlet flue gas data, pollutant concentration and system configuration.

 

4. Scope of supply and order requirements

4.1. Scope of supply  (typical range, which can be increased or decreased according to user demand)

The desulfurization units are mostly constructed by EPC, and the contractor is responsible for all the work generated by the FGD device of the project, including the design, supply, construction, installation, network test and test of all process systems and civil engineering buildings (structures) of the desulfurization device

Inspection and inspection, trial operation, assessment and acceptance, defect elimination, training and final delivery and commissioning, etc,

4.2. Order requirements

The desulfurization system is mostly constructed by EPC, and the ordering requirements shall be reflected in the specially prepared (bidding document for EPC general contract of desulfurization system), which shall at least include technical specifications, scope of supply and services, design scope and design liaison, contents and delivery schedule of technical documents, project general schedule and equipment delivery schedule, construction, installation and commissioning, project organization and management, inspection and test Inspection and acceptance, technical training, subcontracting and outsourcing, standards and specifications, large parts list, etc.