H.C.Bleaching Tower

 

Used in down-flow H.c.H2O, bleaching of waste paper deinking pulp ,wooden pulp and other pulp.

 

 

Tapered design,no short-circuiting,Live bottom design of dilution zone realize high consistency bleaching and discharge of low consistency,make process simple.

 

 

1.Tower Body

Typically fabricated from high-quality stainless steel or specially treated anti-corrosion materials. These materials not only exhibit excellent corrosion resistance, capable of withstanding the erosion of chemicals during the bleaching process, but also possess extremely high strength and stability, able to bear the weight of the pulp inside the tower and the pressure generated by chemical reactions.

 

The height and diameter of the tower body are precisely calculated and designed to provide sufficient volume for accommodating a large quantity of pulp. Simultaneously, it ensures that the pulp has adequate residence time inside the tower to complete the full bleaching reaction.

 

The inner wall of the tower body might undergo special coating treatments, such as ceramic coating or polymer coating, to further enhance its corrosion and wear resistance and prolong its service life.

 

2.Feed Inlet

The position and shape of the feed inlet are meticulously designed, usually located at the upper part or the side of the tower body. The size of the feed inlet is large enough to guarantee that the deinked pulp, groundwood pulp, or other pulp types to be bleached can enter the bleaching tower uniformly at a stable flow rate and speed.

 

The feed inlet might be equipped with buffering devices or distributors to reduce the impact force when the pulp enters and enable it to spread rapidly inside the tower, avoiding local accumulation or uneven concentration.

 

The feed inlet might also be installed with valves and flow controllers for precisely regulating the speed and quantity of the feed to adapt to different production process requirements.

 

3.Discharge Outlet

The discharge outlet is generally located at the bottom of the tower body. Its position and structural design aim to facilitate the smooth discharge of the bleached pulp, reducing resistance and residue.

 

The discharge outlet is usually equipped with control valves and discharge devices, such as screw dischargers or conveyor belts, which can precisely control the speed and flow of the discharge according to the production progress and the requirements of the subsequent processes.

 

To ensure the quality and stability of the discharge, sampling ports and detection devices might be installed near the discharge outlet for timely quality inspection and analysis of the bleached pulp.

 

4.Stirring System

Comprises a stirrer and a driving device. The stirrer usually adopts an efficient impeller or screw design, capable of generating a strong stirring effect inside the tower to ensure thorough mixing of the pulp.

 

The driving device typically consists of a high-performance motor and a speed reducer, able to provide sufficient power and torque to ensure the stable operation of the stirrer in high-concentration pulp.

 

The rotational speed of the stirring system can be adjusted according to the process requirements to achieve different degrees of stirring effects, thereby adapting to the bleaching requirements of different types and concentrations of pulp.

 

5.Heating Device

The heating device can employ methods such as steam heating, electric heating, or heat exchangers to provide the required temperature conditions for the bleaching process. The heating elements are evenly distributed inside or outside the tower body to ensure uniform heating of the pulp.

 

The temperature control system works in conjunction with the heating device, capable of precisely controlling the heating temperature and automatically adjusting it based on the real-time monitored temperature data to maintain the temperature within the set range and ensure the efficient progress of the bleaching reaction.

 

6.Hydrogen Peroxide Injection System

Composed of storage tanks, metering pumps, delivery pipelines, and injection devices. The metering pump can precisely control the injection volume of hydrogen peroxide to ensure its uniform mixing with the pulp in the predetermined proportion.

 

The design of the delivery pipelines and injection devices aims to ensure the uniform distribution of hydrogen peroxide in the pulp, enhancing the reaction efficiency and uniformity.

 

The injection system might also be equipped with filtering devices and pressure regulating devices to guarantee the purity of hydrogen peroxide and the stability of the injection pressure.

 

7.Exhaust Port

Located at the top or a relatively high position on the side of the tower body, it is used to discharge the gases generated during the bleaching reaction, such as oxygen and water vapor.

 

The exhaust port is usually installed with gas treatment devices, such as condensers, filters, or absorption towers, to treat the discharged gases and reduce environmental pollution.

 

The exhaust port might also be equipped with pressure safety valves and monitoring devices to ensure the pressure inside the tower is within the safe range and to detect abnormal situations promptly.

 

8.Temperature and Pressure Monitoring Devices

Temperature sensors and pressure sensors are distributed at different positions of the tower body, capable of real-time monitoring of the temperature and pressure changes inside the tower. These sensors transmit the data to the control system for the operators to timely understand the working status inside the tower.

 

The control system analyzes and processes the monitored data. Once the temperature or pressure exceeds the set range, it will automatically take corresponding measures, such as adjusting the heating power, stirring speed, or exhaust volume, to ensure the safe and stable operation of the bleaching tower.

 

 

1.Feeding

The deinked pulp, groundwood pulp, or other pulp types to be bleached are sent into the high-concentration bleaching tower through conveying equipment, such as pipelines and pumps, from the feed inlet. During the feeding process, the pulp smoothly enters the tower under the action of gravity and conveying pressure.

 

The speed and quantity of the feed are precisely regulated by the control devices at the feed inlet to ensure the liquid level and concentration of the pulp inside the tower remain within the appropriate range, creating favorable conditions for the subsequent bleaching reaction.

 

2.Mixing

Once the stirring system starts, the stirrer begins to rotate at high speed, generating strong shearing force and thrust, causing the pulp entering the tower to mix rapidly and uniformly.

 

The design and rotational speed of the stirrer are optimized based on the characteristics of the pulp and the volume of the tower to ensure thorough mixing of the pulp within a short period, enabling uniform distribution of hydrogen peroxide throughout the pulp system.

 

Simultaneously, the stirring can also promote the dispersion of fibers in the pulp, increasing the contact area between the chemical agents and the fibers and improving the efficiency of the bleaching reaction.

 

3.Heating

The heating device commences operation, heating the pulp inside the tower to the predetermined bleaching temperature. During the heating process, the temperature control system monitors the temperature of the pulp in real-time and automatically adjusts the heating power based on the set value to maintain a stable temperature.

 

An appropriate temperature can activate the bleaching activity of hydrogen peroxide, accelerate the progress of the chemical reaction, and enhance the bleaching effect. Meanwhile, uniform temperature distribution is crucial for ensuring the consistency of the bleaching quality.

 

4.Bleaching Reaction

When the pulp reaches the predetermined temperature and mixing state, the hydrogen peroxide injection system injects precisely metered hydrogen peroxide into the tower. Hydrogen peroxide undergoes chemical reactions with substances such as lignin and chromophoric groups in the pulp, destroying their molecular structures to achieve the purpose of bleaching.

 

The bleaching reaction is a complex process involving multiple chemical reaction steps and intermediate products. Under high-concentration conditions, the fibers in the pulp are in close contact with each other, facilitating the progress of the chemical reaction and the diffusion of products, thereby improving the bleaching efficiency and reducing the consumption of chemical agents.

 

The reaction time is adjusted based on factors such as the type and concentration of the pulp, the temperature, and the dosage of hydrogen peroxide to ensure achieving the desired bleaching effect.

 

5.Exhaust

During the bleaching reaction, gases such as oxygen and water vapor are generated. These gases are discharged outside the tower through the exhaust port and enter the gas treatment device for processing.

 

The exhaust process can maintain the pressure balance inside the tower, preventing damage to the equipment due to excessive pressure. Simultaneously, timely discharging the gases generated during the reaction is also beneficial for promoting the progress of the bleaching reaction and the generation of products.

 

6.Discharge

After a certain period of bleaching reaction, the bleached pulp is discharged from the high-concentration bleaching tower through the discharge outlet. The speed and quantity of the discharge are precisely controlled by the control devices at the discharge outlet to interface with the subsequent production processes.

 

The discharged pulp undergoes detection and analysis to determine whether the bleaching effect and quality indicators meet the requirements. If further adjustments are necessary, the process parameters can be optimized, and the bleaching treatment can be repeated.

 

 

1.Efficient Bleaching

Utilizing high-concentration hydrogen peroxide bleaching technology, it can significantly increase the whiteness of the pulp within a relatively short period, making the pulp meet high-quality requirements.

 

The optimized internal structure of the tower and the stirring system can ensure the thorough contact and reaction between the chemical agents and the pulp, maximizing the bleaching effect of hydrogen peroxide and enhancing the bleaching efficiency.

 

Compared with traditional bleaching methods, the high-concentration bleaching tower can achieve better bleaching effects within the same time and with the same dosage of agents, thereby improving production efficiency and product quality.

 

2.High-Concentration Treatment

Adaptable to the treatment of high-concentration pulp, reducing the dilution of the pulp during the bleaching process and thereby decreasing water consumption and wastewater discharge.

 

Under high-concentration conditions, the interaction between fibers is enhanced, which is beneficial for the progress of the chemical reaction. At the same time, it also reduces the diffusion loss of chemical agents and improves the utilization rate of the agents.

Capable of effectively reducing production costs and environmental pressure, in line with the sustainable development requirements of the modern paper industry.

 

3.Precise Control

Equipped with advanced control systems and monitoring devices, it can precisely control key parameters such as the dosage of hydrogen peroxide, temperature, and reaction time.

 

Through real-time monitoring and feedback, the operators can adjust the process parameters in a timely manner based on the characteristics of the pulp and the bleaching requirements, ensuring the stability and consistency of the bleaching quality.

 

Precise control can also reduce the waste of chemical agents, lower production costs, and improve the controllability and reliability of the production process.

 

4.Energy Saving

The optimized heating system and insulation structure can effectively reduce heat loss and improve energy utilization efficiency.

The reasonable design and operation mode of the stirring can reduce the power consumption of the stirring while ensuring the mixing effect.

 

Compared with traditional bleaching equipment, the high-concentration bleaching tower has obvious advantages in energy consumption, enabling enterprises to save a significant amount of energy costs.

 

5.Environmental Friendliness

Reduces the usage of chemical agents and wastewater discharge, lowering environmental pollution.

Hydrogen peroxide is a relatively environmentally friendly bleaching agent, and its decomposition products are water and oxygen, which are friendly to the environment.

 

The gas treatment device at the exhaust port can effectively treat the exhaust gases generated during the reaction, reducing the emission of harmful gases and protecting the atmospheric environment.

 

 

1.Improving Paper Quality

The pulp processed by the high-concentration bleaching tower has significantly improved whiteness and cleanliness, which can be used to produce high-quality paper, such as high-grade cultural paper and packaging paper.

 

The excellent bleaching effect can enhance the physical and optical properties of the paper, improving the strength, smoothness, and printability of the paper, meeting the market demand for high-quality paper.

 

2.Cost Reduction

Reduces water consumption and wastewater treatment costs, lowering the overall production costs.

Improves the utilization rate of chemical agents, reducing the waste of raw materials and lowering the material costs.

 

The energy-saving feature can reduce energy consumption, further reducing production costs and improving the economic benefits of the enterprise.

 

3.Process Flexibility

Can be well coordinated and integrated with other papermaking process links, such as pulping, screening, and purification, adapting to different production processes and process requirements.

 

Can flexibly adjust the bleaching process parameters according to market demand and raw material changes to produce pulps of different whiteness and quality, meeting the diversified market demands.

 

4.Sustainable Development

Complies with the requirements of the modern papermaking industry for environmental protection, energy conservation, and efficient utilization of resources, contributing to the sustainable development goals of enterprises.

 

Promotes the development of the papermaking industry towards a greener, more efficient, and higher-quality direction, enhancing the social image and competitiveness of enterprises.

 

 

Type	ZPT41	ZPT42	ZPT43	ZPT44
Nominal volume：m³	50	70	100	150
Pulp consistency：%	28～32
Bleaching temperature：℃	60～70
Bleaching time：min	60～90
Capacity of production：t/d	50～80	80～120	120～170	150～260
Power of motor：kw	30	30×2	37×2	37×2

 

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