Chemical Pumps Required in the Paper Industry

1. Pulping Process (Core Link: Slurry and Chemical Transportation)

1.1 Slurry Pumps (Key Equipment for Pulping)

• Centrifugal Slurry Pumps: The most widely used pumps in the pulping process, mainly used to transport high-concentration pulp (concentration 10%-40%), wood chips, and fiber-containing slurry. They feature strong wear resistance (flow parts are made of wear-resistant materials such as high-chromium alloy or rubber lining) and large flow capacity, which can meet the continuous transportation needs of large-scale pulping lines. They are commonly used in wood chip transportation, pulp mixing, and slurry circulation.
• Screw Slurry Pumps: Suitable for transporting high-viscosity, high-concentration pulp (concentration above 40%) and slurry containing large fiber particles. They have stable operation, no clogging, and low shear force, which can avoid fiber damage. They are often used in the transportation of thick pulp and the feeding of pulping equipment.

1.2 Chemical Feed Pumps (Cooking and Pretreatment)

• Magnetic Drive Chemical Pumps: Used to transport corrosive cooking chemicals, such as caustic soda (NaOH), sodium sulfide, and sulfuric acid, which are used in alkaline pulping and acid pretreatment. They adopt a seal-less structure with zero leakage, ensuring safe transportation of toxic and corrosive media, and avoiding environmental pollution and equipment corrosion.
• Reciprocating Plunger Pumps: Suitable for transporting high-pressure cooking chemicals (pressure up to 10-15 MPa), such as the feeding of cooking liquor in the kraft pulping process. They have the advantages of high pressure and precise flow control, ensuring the stable supply of cooking chemicals and improving pulping quality.

1.3 Washing Water Pumps

2. Bleaching Process (Core Requirement: Corrosion Resistance)

• Fluoroplastic Lined Centrifugal Pumps: The flow parts are lined with PTFE, PFA, and other fluoroplastics, which have excellent corrosion resistance to strong acids, strong alkalis, and oxidants. They are widely used to transport bleaching agents such as chlorine dioxide and hydrogen peroxide, as well as acid-base regulating fluids. They have the advantages of low cost, large flow rate, and easy maintenance.
• Magnetic Drive Fluoroplastic Pumps: On the basis of fluoroplastic corrosion resistance, the magnetic drive seal-less structure is adopted, which is suitable for transporting highly corrosive, toxic, and volatile bleaching chemicals (such as concentrated chlorine dioxide solution). It completely avoids leakage, ensuring the safety of operators and the environment.
• Diaphragm Pumps: Suitable for small-flow, high-pressure transportation of bleaching chemicals (such as precise feeding of hydrogen peroxide). They adopt a diaphragm isolation structure, which can prevent the medium from contacting the pump body, and have good corrosion resistance and metering accuracy, ensuring the stability of the bleaching process.

3. Papermaking Process (Core Requirement: Stability and Cleanliness)

3.1 Pulp Beating and Circulation Pumps

• Stainless Steel Centrifugal Pumps: Used to transport low-concentration pulp (concentration 3%-10%) and pulp circulation in the beating process. The flow parts are made of 304 or 316L stainless steel, which is non-toxic, corrosion-resistant, and avoids polluting the pulp. It has large flow rate and stable operation, ensuring the uniformity of pulp beating.
• Circulating Water Pumps: Used to transport process water and cooling water in the papermaking machine, requiring large flow rate, low pressure, and high reliability. Cast Iron Centrifugal Pumps or Stainless Steel Centrifugal Pumps are usually selected, which have simple structure, low energy consumption, and can meet the continuous operation needs of the papermaking machine.

3.2 Sizing and Coating Pumps

• Gear Pumps: Suitable for transporting high-viscosity sizing agents (such as starch, rosin sizing agent) and coating materials (such as latex, kaolin). They have compact structure, good self-priming performance, and stable flow rate, ensuring uniform sizing and coating of paper sheets, and improving paper surface quality.
• Peristaltic Pumps: Used for precise metering and transportation of small-flow sizing agents and additives (such as defoamers, preservatives). They have high metering accuracy, no pollution to the medium, and can avoid the clogging of the pump body by high-viscosity media, which is suitable for the precise control of the papermaking process.

4. Finishing Process (Core Requirement: Corrosion Resistance and Precision)

• Corrosion-Resistant Centrifugal Pumps: Used to transport cooling water (containing scale inhibitors and corrosion inhibitors) and cleaning agents (such as weak acid cleaning solutions) in the drying and calendering process. They have good corrosion resistance and stable operation, ensuring the normal operation of finishing equipment.
• 计量 Pumps (Metering Pumps): Also known as dosing pumps, they are used to add auxiliary chemicals (such as antistatic agents, waterproof agents) to the paper surface. They have high metering accuracy, adjustable flow rate, and can accurately control the dosage of chemicals, ensuring the finishing effect of paper.

5. Auxiliary Systems (General Requirements: Reliability and Durability)

• Wastewater Treatment Pumps: Used to transport papermaking wastewater (containing pulp residues, chemicals, and organic pollutants), requiring wear resistance and corrosion resistance. Submerged Slurry Pumps or Corrosion-Resistant Centrifugal Pumps are selected, which can adapt to the characteristics of high suspended solids and slight corrosion in wastewater, and avoid clogging and pump body corrosion.
• Boiler Feed Water Pumps: Used to transport boiler feed water and softened water, requiring high pressure and high reliability. Multistage Centrifugal Pumps are preferred, which have high head and stable performance, ensuring the normal water supply of the boiler and the stability of the production line’s energy supply.
• Chemical Storage and Transportation Pumps: Used to transport chemicals stored in the chemical warehouse (such as caustic soda, sulfuric acid, hydrogen peroxide) to each production link. According to the characteristics of the medium, Magnetic Drive Pumps (corrosive and toxic media) or Centrifugal Pumps (non-corrosive media) are selected to ensure safe and efficient transportation of chemicals.

6. Key Selection Principles of Chemical Pumps in the Paper Industry

• Prioritizecorrosion resistance: According to the type of chemical medium (acid, alkali, oxidant), select pumps with corresponding corrosion-resistant materials (fluoroplastics, stainless steel, Hastelloy) to avoid pump body damage and medium leakage.
• Focus on wear resistance: For slurry and particle-containing media (pulp, wastewater), select pumps with wear-resistant linings or hardened flow parts to extend the service life of the pump.
• Match flow rate and pressure: According to the production scale and process requirements, select pumps with appropriate flow rate and head to ensure the stability of the transportation system.
• Pay attention to safety and environmental protection: For toxic, corrosive, and volatile media, select seal-less pumps (magnetic drive pumps) to avoid environmental pollution and safety accidents.