| Certification: | ISO |
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| Installation Method: |
Horizontal |
| Operation Type: |
Semiautomatic |
| Medium Material: | Metal Fiber |
| Dust Collecting Method: | Half Dry |
| Type: | Gas-Water Separation Technology |
| Customization: |
|---|
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Solution Overview
"SCR denitration + new heat exchanger + washing tower + lime desulfurization process", the process diagram is as follows:
A new system is added to the original system
After site survey, the flue gas temperature after the original waste heat recovery heat exchanger is 320-370ºC, which is in line with the use temperature range of medium-high temperature denitrification catalyst. The most mature SCR denitrification process is adopted, and the highest denitrification efficiency can reach more than 90%, which makes the NOx concentration at the outlet of denitrification reactor can be reduced to below 150mg/m³, reaching the national ultra-low emission standard.
After denitration temperature still have 320-370 ºC, if the temperature directly into the wet desulphurization system, on the one hand, the high temperature for the reaction against, on the other hand, have to spray a large amount of water to cool the flue gas, causing the tower water volume is too big, must discharge to ensure the water balance of the whole system, and will cause the new secondary water pollution.
Therefore, it is imperative to cool the flue gas after denitration. A new section of heat exchanger tube is added to reduce the flue gas temperature to below 150ºC through the cooling tower.
Due to the cooling of the flue gas, the smoke volume of the induced draft fan is increased to 100000m³/h(150ºC), and the full pressure is 4000Pa.
Since the maximum concentration of particulate matter at the outlet of the heating furnace can reach 120mg/m³(after 8% oxygen conversion), to achieve the emission concentration of 10mg/m³ at the outlet of the desulfurization tower, wet washing tower must be set before the desulfurization tower for pre-dust removal on the premise of no new bag filter.
After washing, the slurry is filtered into the plate and frame filter press to remove the particles washed down.
After washing the column, the concentration of particulate matter was reduced to 60mg/m³.
The desulfurization tower is set after the washing tower. The desulfurization tower is mainly composed of slurry pool, spray layer, tray, high efficiency defogger and other components.
After the flue gas enters the tower, it first passes through the tray to realize the redistribution of flue gas and achieve the effect of uniform distribution of flue gas.
After that, the flue gas passes through the spray layer to achieve the desulfurization effect. After the desulfurization, the flue gas passes through the efficient defogger. The efficient defogger realizes the sufficient swirling and collision of the flue gas to remove the escaping particles in the washing tower and achieve the effect of dust removal and defogging.
The flue gas is discharged to the standard through the flue pipe after the efficient defogger.
Operation cost analysis
The lime consumption, power consumption and process water consumption of the desulfurization system are calculated, and the corresponding operation cost is calculated.
The operation time of the desulfurization system is considered as 8000 hours.
No. Consumption/Product Name Hourly consumption Annual consumption Unit price cost (ten thousand yuan) Remarks
| Number | Consumption/product name | Consumption per hour | Annual consumption | The unit price | Cost (ten thousand yuan) | Note |
| One | Electricity | 220kw.h | 1760000kw.h | 0.5/KW·h | 88 | Contain the induced draft fan |
| Two | Lime | 0.029t/h | 232t | 300/t | 6.96 | |
| Three | Industrial water | 1.5t/h | 12000t | 1.5/t | 1.8 | |
| Four | The urea | 0.0096t/h | 76.8t | 2200/t | 16.9 | |
| Total (ten thousand yuan) | 114 | |||||
| Note: The operation cost of full smoke gas, the highest NOx and the highest SO2 concentration, the actual operation cost is about 50-80%. | ||||||
SCR is out of stock
Denitration design parameters
| Heating furnace smoke volume | 56000Nm3/h |
| Denitration method | SCR denitration system |
| Denitration reducing agent | Urea |
| NOx concentration | ≤350 mg/m3 |
| NOx concentration after SCR denitrification (measured by NO2) | < 150mg/m3 |
| Ammonia escape concentration | ≤3ppm |
|
Number |
The project name |
Single bit |
data |
|
() |
Performance data (single furnace) |
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|
1.1 |
General data |
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|
-NSR |
mol/mol |
||
|
-NOxRemoval rate |
% |
≥86 |
|
|
-Ammonia escape rate of denitration plant |
ppm |
≤3 |
|
|
-Availability of denitration device |
% |
≥98 |
|
|
-Air leakage rate of denitration unit |
% |
0.5 |
|
|
1.2 |
Consumables |
||
|
-Reducing agent (urea) |
t/h |
0.0096 |
|
|
-Saline removal (maximum consumption) |
m3/h |
0.09 |
|
|
-Compressed air for instrument |
Nm3/h |
||
|
-Process compressed air |
Nm3/h |
0.3 |
|
|
1.3 |
Contaminant concentration at outlet of denitration plant (3% O2, dry base) |
||
|
-NOx(NO2 ) |
mg/m3 |
<150 |
|
|
-NH3 |
ppm |
≤3 |
|
|
1.4 |
Noise level (maximum) |
||
|
-All equipment (measured 1 m away from sound source) |
dB(A) |
Schematic diagram of SCR denitrification process
Urea supply system
Transport THE BAGGED UREA FROM OUTSIDE TO THE PLANT and SEND IT TO THE UREA STORAGE AREA of UREA station for storage.
The bagged urea is poured into the pit at the entrance of the bucket elevator by manual bagging, and the granule dry urea enters the urea dissolution tank through the bucket elevator.
The dissolved water connected to the plant is mixed with urea in the dissolved tank, which is equipped with a stirring device and heated by steam mixing directly to accelerate the dissolution of urea.
A certain concentration of urea solution is prepared by controlling the amount of water and urea through the valve.
The tank is equipped with a liquid level detection system to control the total amount of urea solution in the tank.
The dissolved urea solution is sent to the urea solution storage tank by the batching pump.
The system is equipped with one urea dissolution tank and one urea solution storage tank.
The volume of the urea dissolution tank meets the urea solution consumption of one heating furnace in one day under rated load.
The total storage capacity of the urea solution tank can meet the consumption of a heating furnace for 7 days under rated load.
Urea solution delivery system mainly includes urea solution delivery pump, and the corresponding unit of the medium delivery pipeline, valve, etc., from the public system tank outlet to the furnace delivery pipeline.
This project is equipped with 2 urea solution delivery pumps (1 for use and 1 for backup).
Urea solution metering and distribution system
Each furnace is equipped with a set of urea solution measurement and distribution system, including urea solution pipeline, compressed air pipeline, flushing water pipeline, flow measurement device and instrument.
Urea solution pipeline is provided with a flow regulating valve, which can adjust the urea solution throughput according to the change of NOx.
Each furnace is provided with a spray gun and the corresponding auxiliary system.
catalyst
The SCR reactor adopts plate catalyst "2+1" arrangement (two layers of catalyst are used, and the installation space and position of one layer of catalyst are reserved).
Catalyst treatment flue gas design parameters (dry base, 8%O2)
| No | Item | Unit | Value | Remarks |
| One | Smoke volume | Nm³/h | 56000 | |
| Two | Reaction temperature | ºC | 320-400 ºC | |
| Three | Requires volume | m3 | 15 | |
| Four | Oxygen | % | 8 | |
| Five | SO2 | mg/m³ | ||
| Six | Dust concentration | mg/m³ | ≤120 | |
| Seven | NOx concentration | mg/m³ | ≤350 | |
| Eight | moisture content | % | ≤3 |
soot blower
Compressed air was used to clean the catalyst surface.
One acoustic soot blower is designed for each layer of catalyst.
The mechanical part of the acoustic soot blower is designed to be of sufficient strength, and the design of the hanging fixtures of the external device of the soot blower (outside the reactor) shall consider the simultaneous thermal expansion with the reactor body.
High temperature resistant materials should be selected and corresponding measures should be taken to prevent ash accumulation.
It shall be able to withstand operating temperature of 420ºC for not less than 8 hours without any damage.
washing desulfurization
1.Basic design conditions
2.Smoke parameters
Original flue gas emission parameters Flue gas flow 56000Nm3/h Smoke temperature 150ºC
Inlet SO2 concentration 350mg/m3 Inlet dust 120mg/m³
Lime purity ≥90% SO2 emission concentration ≤50mg/m3
water
| Process water quality | Industrial water (clarified water) |
| Process water pressure | inlet ≥ 0.2mpa |
| Process water temperature | ≤ 40 ºC |
Compressed air
The pressure of the compressed air in the desulfurization system is ≥ 0.4mpa, and the compressed air should be clean and dry, oil-free and dust-free.
power
Low voltage power supply: 380/220V three-phase four-wire;
Frequency: 50Hz.
Control power supply: 220V, AC.
Design Scope
Technical Principles
The project uses wet washing + lime - gypsum wet desulfurization + efficient defogging process to ensure higher desulfurization and dust removal efficiency.
The desulfurization process adopted in this scheme is summarized as follows:
The washing tower is equipped with two layers of spray and one layer of defogger to wash and cool the flue gas entering the tower, so as to ensure that the concentration of particulate matter at the exit is reduced to about 60mg/m³.
Desulfurization tower with lime powder as the absorbing agent, in the absorption tower to spray washing contains SO2 flue gas SO2 and the slurry in the alkaline substances react to generate calcium sulfite and bisulfite calcium, thus SO2 removal from the flue gas, in the bottom in oxidation pond, forced oxidation generated after calcium sulphate, in the bottom pool slurry solid matter separated from the slurry,
After dehydration by plate and frame filter press, solid gypsum by-product is generated.
From the bottom pool of the tower to add lime slurry to adjust the pH value, after the circulating pump into the desulfurization tower desulfurization, recycling use.
Other acidic gases such as HCl and HF contained in flue gas can also be absorbed by alkaline in the absorber.
Flue gas from the lower part of the absorption tower into the tower, in the process of rising in the tower and desulfurizer circulating slurry contact, SO2 gas in the flue gas is removed after the efficient defogger, remove the entrain droplets in the flue gas, and finally clean flue gas from the top of the absorption tower into the chimney discharge into the atmosphere.
The circulating slurry of desulfurizer is atomized downward into the tower by the nozzle arranged in the upper part of the absorption tower, and the small droplets are convective contact with the bottom-up flue gas to form a high-efficiency gas-liquid contact, so as to promote the removal of acid gases such as SO2 in the flue gas.
At the same time, in the process of flue gas rising in the tower, because of the capture of desulfurizer fine slurry, but also can wash away most of the fine dust;
When the flue gas passes through the defogger, it can not only remove the fog droplets, but also remove some fine particles, which can further improve the dust removal efficiency of the system.
The chemical reaction mechanism is as follows:
SO2 (g) and SO2 (aq)
SO2 (aq) + H2O (l) - > H++ HSO3 - - 2 h + + SO32 -
CaO (s) + H2O - Ca2 + + 2 oh -
HSO3 - + 1/2 O2 (g) and SO42 - + H +
H++ SO42 - + Ca2 + + CO32 - + 2 h2o and CaSO4 • 2 h2o + HCO3 - (s)
The total reaction equation is:
SO2(G)+ CaO(S)+1/2 O2(G)+2 H2O(L)→CaSO4•2 H2O(S)
After forced oxidation and solid-liquid separation, the solids are discharged into the system as by-products in the form of gypsum, and the filtrate is returned to the absorption system for recycling.
The system uses PLC control mode, improve the degree of system automation, ensure the stable operation of the whole system.
The desulphurization system takes into account appropriate changes in flue gas sulfur content and is designed in combination with the maximum load flue gas parameters.
Use an efficient defogger to ensure low free water content in the exhaust gas.
In addition, the flue heat preservation measures to prevent the flue gas with water and reduce condensation, reduce the corrosion problem of downstream equipment.
Material selection is guaranteed to adapt to the requirements of actual operating conditions, considering appropriate corrosion allowances.
All equipment and piping will be designed to withstand the maximum thermal and mechanical stresses that the equipment and piping can withstand in the event of failure, taking into account the worst operating conditions and safety margins in the event of an accident.
Desulphurization device should be arranged reasonably according to local conditions, and minimize the area of desulphurization device as much as possible.
The impalers of all pumps are wear-resistant, corrosion-resistant materials, and the bearing seals of the pumps are mechanical seals.
The equipment provides the right number of access ports, sampling ports, and manhole doors, which are set as close to the platform as possible.
Equipment and piping take into account both the implementation of the system's functions and the ease of operation.
Outdoor equipment provides essential protection against rain and freezing.
Performance Guarantee
Performance Guarantee
The guaranteed values of washing desulfurization performance are as follows:
No. Indicator Indicates the unit parameter
1. Ensure the desulfurization efficiency % ≥95
2 Ensure that the emission concentration of SO2 mg/m3 is less than 50
3 Ensure that the emission concentration of dust and dust mg/m3 is less than 10
4 Ca/S ratio is 1.03
5 Liquid-gas ratio L/Nm3 10
6. The total resistance of the washing desulfurization system is Pa 1700
7 Desulfurization by-product gypsum purity % 90
8. Load adaptation range of desulfurization and dust removal device % 40-110
Description of each component design of washing desulfurization
Desulfurizer preparation and supply system
(1) System overview
The purchased lime powder with a purity of not less than 90% is unloaded to the lime dissolution tank, and the slurry is made by adding water and stirring. The slurry concentration is 20-30%, and the slurry is transported to the absorption tower through the pipeline by the lime slurry pump.
(2) Design principles
The supplier guarantees that the lime storage and supply equipment can meet the application requirements.
Pipeline system
The SUPPLIER SHALL PROVIDE THE DESIGN OF ALL PIPES, VALVES, METERS, CONTROL EQUIPMENT AND ACCESSORIES REQUIRED BY THE SYSTEM AND THE SUPPLY OF RELATED METERS AND accessories (PIPELINES, VALVES AND METERS ARE CONSIDERED ANTICORROSIVE).
No dead zone exists in slurry pipeline layout to avoid pipeline blockage.
The grout line is designed with a cleaning system and a valve low drainage system.
The feeding amount of lime slurry is controlled according to the SO2 concentration at the inlet and outlet of the device and the pH value of the slurry in the absorption tower.
Flue gas system
(1) System overview
The flue gas from the flue after the induced draft fan enters the washing - desulfurization absorption tower (hereinafter referred to as the absorption tower).
It is desulfurized and purified in the absorption tower, and the water mist is removed by the mist eliminator and discharged directly into the atmosphere by the absorption tower.
(2) System resistance
The overall resistance of the desulfurization system is less than 1700PA.
absorption tower
The lime slurry is sent from the bottom of the slurry pool of the absorption tower to the injection system in the tower through the circulating pump, and the chemical reaction occurs when it contacts with the flue gas to absorb the SO2 in the flue gas. In the circulation area of the absorption tower, the oxidized air is used to oxidize calcium sulfite to calcium sulfate, and the gypsum discharge pump sends the gypsum slurry from the absorption tower to the gypsum dehydration system.
The droplet entrained by desulphurized flue gas should be collected in the defogger at the outlet of the absorber so that the droplet content of the net flue gas does not exceed the guaranteed value.
The oxidation of calcium sulfite in the slurry tank of the absorption tower uses air oxidation, and other compounds should not be added.
The absorption tower, the whole slurry circulation system and the oxidizing air system should be optimized as far as possible to adapt to the change of load and ensure the desulfurization efficiency and other technical indicators to meet the relevant requirements.
The SO2 absorption system includes at least but is not limited to the following parts: absorption tower, slurry spraying, slurry circulation and stirring of absorption tower, gypsum slurry discharge, flue gas defogging, oxidized air, and other parts, as well as auxiliary vent and vent facilities.
The upper limit of chloride concentration for corrosion resistance in the absorber is 20g/L.
The noise of all equipment shall meet the requirements of the relevant code.
The absorber includes the absorber housing, nozzle and all internal components, absorber stirrer, defogger, etc.
All components in the absorber shall be able to withstand the impact of the maximum inlet air flow and the maximum inlet flue gas temperature, and the high-temperature flue gas shall not cause damage to any system and equipment.
The material selected for the absorber should be suitable for the characteristics of the process, and can withstand the wear of flue gas fly ash and solid suspended matter in the desulfurization process.
All components including the tower body and internal structure shall be designed with consideration of corrosion residuals.
The absorber is designed to be air-tight to prevent liquid leakage.
To ensure structural integrity of the shell, weld connections are used whenever possible, flanges and bolt connections are used only when necessary.
The manholes, channels and connecting pipes on the tower body need to be sealed where the shell is perforated to prevent leakage.
The ABSORBER housing IS DESIGNED TO WITHSTAND PRESSURE LOADS, PIPE FORCES AND MOMENTS, wind LOADS, snow LOADS AND SEISMIC LOADS, AND ALL OTHER LOADS placed ON THE ABSORBER.
The supports and stiffeners of the absorber shall be sufficient to prevent the tilt and sloshing of the absorber.
The tower is designed to avoid the formation of dead corners as much as possible, and stirring measures are used to avoid slurry precipitation in the slurry pool.
The absorber is equipped with a sufficient number of nozzles.
The overall design of the tower facilitates the overhaul and maintenance of the inner parts of the tower. The guide plate, spray system and support in the absorption tower do not accumulate dirt and scale as much as possible, and the channel is provided for easy cleaning.
Reasonable design of oxidizing area and reasonable arrangement of oxidizing air distribution pipe.
The absorber stirring system ensures that the gypsum slurry in the tower does not precipitate, scale or clog at any time.
The inlet section of the flue of the absorption tower is designed at an inclined Angle and equipped with flushing water to prevent flue gas backflow and solid accumulation.
The absorption tower shall be provided with a sufficient number of manhole doors and observation holes of suitable size as required. The manhole doors and observation holes shall not have leakage, and walkways or platforms shall be provided nearby.
Each absorber system also includes all necessary in situ and distant measuring devices to provide at least adequate measurement points for absorber level, pH meter, temperature, density, pressure, defogger differential pressure, etc.
Slurry spraying system
The slurry spraying system inside the absorber is composed of distribution pipe network and nozzle. The design of the spraying system can reasonably distribute the required amount of spray, make the flue gas flow evenly, and ensure the full contact and reaction between the lime slurry and the flue gas.
Each absorber is provided with 2 spray layers.
The absorption tower is equipped with a large number of nozzles in the spray layer, the spray Angle has a certain proportion of overlap, and the spray coverage density is not less than 250%.
All nozzles can avoid rapid wear, scaling and clogging. The nozzles are made of 316L material.
Nozzles and pipes shall be designed to facilitate maintenance, flushing and replacement.
The absorber is equipped with a large number of nozzles in the spray layer, and the spray Angle has a certain proportion of overlap.
Oxidation system
Oxidation fan configuration: flow margin is 10%, indenter margin is 20%, oxidation fan is Roots type.
The oxidation fan can provide enough oxidized air, and the arrangement of the oxidation duct is reasonable, so that the calcium sulfite in the absorption tower is fully converted into calcium sulfate.
The fan operates at the highest efficiency point.
The fan has an almost flat efficiency characteristic curve to ensure that the unit has the best efficiency under various loads during operation.
Fan noise meets relevant standards.
The oxidation duct outside the absorption tower is used for insulation.
The oxidized air duct material distributed in the absorption tower shall be at least 316L material.
Technical after-sales service
Based on the principle of serving customers and satisfying them, the company makes the following technical and after-sales service commitments and security guarantees to users using our technology and products:
After-sales service period: lifelong technical services
Free service period: warranty period
Provides users with timely, speedy, and quality service.
Help users solve technical problems in dust removal, desulfurization and denitrification, and provide technical guidance and technical consultation for them;
We guarantee the correctness, integrity, reliability and technical advancement of the design, manufacture and supply equipment, using high-quality materials and first-class technology, and in all aspects in accordance with the quality, specification and performance requirements stipulated in the contract;
We guarantee to complete the design, manufacture, supply, installation and commissioning within the agreed time;
We provide the corresponding construction drawings and technical support as required, and cooperate with the owner to do the acceptance work;
The warranty period is one year from the date of installation and commissioning of the equipment.
In the normal use of the equipment within the warranty period, if quality problems and failures are found, the implementation of three guarantees of service (except wearing parts), free maintenance, can not be maintained, free replacement, quality problems and failures found outside the warranty period, we timely repair and only charge cost;
we guarantee to provide long-term supply of spare parts and technical service for the manufacturer, we have the duty to provide as soon as possible replacement parts, the buyer need for urgent parts, we will arrange the fastest way to transport, our long-term supply of spare parts used for the user, system couldn't solve the problems appeared in the process of using,
We will invite experienced engineers to provide technical services in time.
We develop practical operating procedures and use guidelines for users;
Provide users with operation methods and operation techniques training, ensuring that users and employees operate the system correctly and safely;
We will design in strict accordance with relevant technical and safety standards, and we will be responsible for any safety problems caused by us during the construction process of the project;
We conduct irregular return visits and technical exchanges with users, so that the manufacturer can constantly improve the level of use and play the role of the purchased system.
Other services
Personnel Training
The training of field operators mainly covers the whole system process, pump operation and precautions, equipment operation, electrical operation, equipment maintenance, drug delivery, and overall equipment operation, etc.
Introduces the entire process, detailing the control elements and amounts at each critical control point (CRP).
Know which part of the system is operating abnormally, such as noise or abnormal vibration, when a pump is running.
Learn to pump simple maintenance overhaul.
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