PP Flame Retardant Additive Drum

Product Model	PPs Welding Drug Storage Stirring Tank
Category	PP Machined Products
Reference Price	Price on request

Hot Customizable for Working Conditions 11 Technical Parameters

Product Overview

The PP Flame-Retardant Chemical Dosing Drum is a plastic container used in flue gas scrubbing systems for storing and preparing absorbent chemicals. It is constructed from PP flame-retardant sheets through processes such as cutting, rolling, folding, welding, and reinforcement. In flue gas scrubbers treating acid mists, alkaline agents like sodium hydroxide are typically added to the circulating liquid to neutralize acidic gases. The dosing drum stores the chemical mother liquor or prepared absorption liquid and is replenished into the tower's bottom water tank via a dosing pump, either automatically or manually, based on the pH value of the circulating liquid.

Due to the long-term storage of acid and alkali liquids, metal containers are prone to corrosion, while ordinary concrete pools are susceptible to leakage. PP sheet material is resistant to acid, alkali, and salt corrosion, forms leak-proof welds, is lightweight, and offers flexible processing, making it a common choice for corrosion-resistant chemical storage containers. The use of PP flame-retardant sheets ensures that the drums in indoor dosing rooms have self-extinguishing properties, reducing fire hazards in chemical storage areas. The drum body can be designed as a vertical cylindrical or square shape. Cylindrical drums offer better load-bearing capacity, while square arrangements save space.

Xicheng Environmental can design and manufacture PP flame-retardant dosing drums based on chemical types, dosage requirements, and dosing room space. The drums can be equipped with dosing ports, manholes, inlet/outlet liquid ports, overflow ports, drain ports, level indicators, ladder railings, and motor installation platforms for mixers. They can also be paired with dosing pumps, mixers, and pH online control to form a complete automated dosing system, with volume and interface positions customized to project needs.

Working Principle

The dosing drum serves as a storage, preparation, and constant-level supply unit in the dosing system. Solid or concentrated chemicals are added through the dosing port into the drum, where they are mixed with water to form a solution of a specific concentration. For uniform mixing, a stirrer motor is installed on the drum top to drive paddles, accelerating dissolution and preventing sedimentation. The dosing pump draws liquid from the bottom outlet of the drum and replenishes the system intermittently or continuously based on pH signals from the circulating water tank. The drum's liquid level is monitored by a level indicator, with an alarm prompting refilling when the level is low.

The drum's corrosion resistance and leak prevention rely on the PP sheet material and welds of the same material. Polypropylene does not react with common alkaline chemicals like sodium hydroxide or dilute sulfuric acid. The welds are made using hot melt welding with the same material electrodes, ensuring dense, leak-proof joints. The overall structure avoids the rusting issues of metal containers. The flame-retardant components make the sheet material self-extinguishing. Cylindrical drum bodies distribute circumferential stress evenly when filled, while square drums resist lateral liquid pressure through external reinforcement ribs and clamps. The thickness of the drum bottom and walls is designed based on the liquid density and liquid level height to prevent bulging or deformation.

Structural Components

The dosing drum consists of a drum body, a lid or reinforcing frame, a base plate, interfaces, and accessories. Cylindrical drums are formed by rolling and welding PP sheets, while square drums are created by folding and welding. Multiple reinforcing rings or ribs are welded along the outer wall of the drum walls based on the liquid level height. The drum bottom is thickened and equipped with a base or legs to elevate the drain port, positioning it at a low level for easy emptying.

The drum top is equipped with dosing ports, manholes, stirrer shaft holes, and vent ports. The lower part of the drum wall has an outlet liquid port, the upper part has an overflow port, and the bottom has a drain port. All interfaces are welded with PP flanges or threaded connections for pipeline valves. Optional accessories include level indicators (buoy, hydrostatic, or magnetic float), mixers with installation platforms, external ladders and top railings, and level alarms. A complete dosing system integrates the drum, metering pump, mixer, pH meter, and control cabinet on a single base, ready for operation after field connection and power supply.

Specification and Model Table

The following table provides an overview of the forms and configurations of the dosing drums, with volumes designed based on chemical usage.

Item	Form / Configuration	Description
Drum Shape	Cylindrical / Square	Choose based on space
Material	PPs Flame-Retardant Sheet	Corrosion-resistant, self-extinguishing
Stirring	Top-mounted mixer optional	Prevents sedimentation, promotes dissolution
Complete Set	Pump, meter, and control cabinet integrated optional	Automated dosing

Product Features

The PP Flame-Retardant Dosing Drum is corrosion-resistant, leak-proof, flame-retardant, and configurable, serving as the core chemical storage device in flue gas scrubber dosing systems. Key features include:

PPs sheet welding, resistant to acid/alkali and self-extinguishing
Same-material electrodes for hot melt welding, dense joints without leakage
Multiple shapes (cylindrical/square), volume customized to usage
Reinforced outer rings and thickened base plate, maintains shape under full liquid
Comprehensive interfaces with rational layout for overflow, drain, and manholes
Optional stirrer, level indicator, and ladder for operation and maintenance
Can be integrated with metering pumps and pH control for automated dosing

Material	PPs Flame Retardant Panels
Processing Technology	Rolling / Folding Plate Welding
Drum-shaped	Cylinder / Square
Storage media	Acid-Base Absorption Liquid
Strengthening Method	Outer wall reinforcement ring
Flame Retardancy	Self-extinguishing
Corrosion resistance performance	Acid and Alkali Salt Resistant
Optional Accessories	Stirrer Level Gauge Ladder
Specifications and Features	Non-standard Customized Capacity
Liquid Level Monitoring	Optional Level Gauge
Wastewater Disposal Configuration	The drum is equipped with a drainage outlet at the bottom.

Application Industries

Sodium Hydroxide Dosage System Storage Tank for Acid-Base Scrubber
Neutralization Dosage Device for Electroplating Wastewater and Gas Treatment
Acid-Base Liquid Preparation and Storage Tank for Chemical Tail Gas Absorption Tower
Medicine Storage Tank in Dosage Room for Acid-Base Vent Scrubber in Semiconductor Plants
Medicine Box for pH Adjustment Dosage System in Wastewater Treatment Plants
Recirculating Dosage Tank for Acid Pickling Acid Mist Purification Tower in Metallurgy
Corrosion-Resistant Medicine Storage Container with Fireproof Requirements for Indoor Dosage Room

Typical Process Locations

The dosage tank is installed in a dosage room or equipment area near the scrubber, positioned above the dosage pump or adjacent to the pump group, with the suction pipeline kept as short as possible. The tank stores prepared absorption liquid, and the metering pump's outlet pipe connects to the tower's bottom circulation water tank or circulation pipeline. The pH electrode is installed in the circulation liquid loop, with the controller controlling the start/stop of the dosage pump based on pH. A sump or diversion channel is installed around the tank to prevent overflow, with leaked liquid collected and treated. Sufficient space is left near the dosage port for chemical handling and addition.

During installation, the tank body is positioned on a level foundation or base, with legs or bases ensuring even load distribution. Fully liquid-filled tanks must not be suspended. Inlet/outlet, overflow, and drain pipelines are independently supported, with valve weights not bearing on the tank wall connections. For stirred tank models, the top platform must be checked for load-bearing capacity, and the stirrer must be concentrically installed to prevent impeller wall abrasion. Before operation, a full-water test is conducted to check welds and joint leaks. The level gauge and low-level alarm are linked to the dosage pump to prevent air suction. The chemical storage area is equipped with labels and flushing facilities in compliance with chemical management requirements.

Capacity is determined based on daily chemical consumption, replenishment cycle, and preparation batches. Generally, the effective capacity is designed according to the chemical usage for several consecutive days of system operation, considering additional space for mixing and liquid level protection to avoid frequent daily preparation and prevent excessive chemical sedimentation or degradation due to large capacity. Complete dosing systems are often configured with one in use and one on standby or alternating double drums. Provide the treatment air volume, pollutant concentration, type of absorption chemical, and desired replenishment cycle, and the manufacturer or designer can calculate the capacity and number of drums accordingly.

PP exhibits excellent corrosion resistance to alkaline solutions such as sodium hydroxide and can be safely stored within ambient concentration ranges. Weld joints using the same material electrode will not be corroded by alkaline solutions. Attention should be paid to the exothermic effect of strong alkali dilution; when preparing, follow the operating procedures by adding water first, then slowly adding the chemical while stirring to avoid local overheating. The combination of concentrated alkali and high temperature will accelerate material aging, so design temperature should have a safety margin. For other chemicals such as strong acids, oxidizers, and organic solvents, verify the compatibility of PP separately – do not generalize that PP is resistant to all chemicals.

When adding solid agents (such as caustic soda, soda ash) which require dissolution, where the liquid solution tends to precipitate, or when a uniform concentration throughout the entire drum is required, a top-mounted agitator should be used to accelerate agent dissolution and prevent active ingredients from settling at the bottom of the drum. For using finished liquid agents with uniform concentration and small dosage, an agitator is not necessary; manual stirring or circulation pump backflow stirring can be used instead. The power, impeller type, and rotation speed of the agitator should be selected based on the drum volume, liquid properties, and dissolution rate. The rotation speed should not be too high to avoid air entrapment, splashing, and drum wall damage. Even with an agitator installed, the solution should be stirred evenly before re-adding agents after long-term static storage, and the corrosion resistance and sealing condition of the impeller and shaft should be checked. The material of the agitator must be corrosion-resistant to the matched liquid agent, and leakage prevention measures should be taken at the shaft seal. During operation, the agitator's effectiveness should be monitored in conjunction with liquid level and concentration checks.

The welded seams of the PP medicine drum are fused with the base material, ensuring no leakage under normal use. Leakage typically occurs at welding defects, stress concentration points at joints, or cracks in the drum body due to deformation. Before putting a new drum into use, a full water test should be conducted: fill the drum with clean water and let it stand for the specified duration to check for any leakage or sweating at all longitudinal seams, bottom seams, and joints. For square drums, observe for deformation at the reinforcement points. If leakage is detected during operation, drain and clean the drum before repairing the welding; never perform hot work with the drum containing the chemical. Flexible connections or supports should be installed on the inlet and outlet pipelines to prevent the weight of the valves and pipes from being applied to the drum wall joints for extended periods.

The cylindrical drum features uniform stress distribution, material savings, smooth inner wall for easy cleaning, and no stirring dead zones. It offers the lightest structure and most material-efficient design for the same volume, making it suitable for spaces that allow for independent placement. The square drum has a compact planar layout, enabling multiple drums to be placed side by side with minimal floor space. Its top platform facilitates the installation of mixers, dosing pumps, and pipelines, making it ideal for tight spaces in dosing rooms with multiple drums arranged in parallel. However, the square drum requires more reinforcing ribs and thicker wall panels to withstand liquid side pressure. When selecting, consider the dosing room layout, single-drum capacity, mixing requirements, and equipment installation needs. Large-capacity storage drums are preferably cylindrical, while complete dosing systems often use square drums in multi-drum configurations. Regardless of the shape, ensure the drum strength, foundation load-bearing capacity, and corrosion resistance meet requirements, while also leaving space for maintenance, dosing, and liquid level observation.

Yes. A typical automated dosing system consists of a dosing drum, agitator, metering pump, pH online instrument, level gauge, and control cabinet: The pH electrode detects the acidity/alkalinity of the circulating liquid. When the value falls below the set point, the controller activates the metering pump to add chemicals. The pump stops when the set point is reached. A low-level alarm in the drum prompts chemical preparation, and the agitator runs on a timer or during chemical addition. The metering pump allows for adjustable dosing, with dual pumps providing redundancy for enhanced reliability. It is important to note that automated dosing still requires periodic manual chemical preparation, pH electrode calibration, and chemical inventory checks. Automation reduces daily operations but not all maintenance tasks.

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