Detergent Powder Plant

Detergent powder is a surfactant or a mixture of surfactants with "cleaning properties in dilute solutions. These substances are usually alkyl benzenesulfonates, a family of compounds that are similar to soap but are more soluble in hard water, because the polar sulfonate (of detergents) is less likely than the polar carboxyl (of soap) to bind to calcium and other ions found in hard water. Powder detergents work because they are amphiphilic - partly hydrophilic (polar) and partly hydrophobic (non-polar). Their dual nature facilitates the mixture of hydrophobic compounds (like oil and grease) with water. Detergent powder falls into four major groups :

• Heavy duty detergents (high and low foaming),
• Light duty detergents,
• Soap powders, and
• Soda products.

Uses :

• The major use of detergent powders is in households for washing clothes and utensils. They are suitable for hand washing and also for machine washing in laundries and dish washers.
• The major raw materials used to produce detergent powder are Alkyl benzene sulphonic acid, sodium tri polyphosphate, sodium sulphate, sodium silicate, and caustic soda. Caustic soda can be obtained locally while the other raw materials are supposed to be imported. However, there is a possibility to manufacture sodium sulphate and sodium silicate locally as the starting materials for these chemicals are locally available. Auxiliary material i.e. printed polyethylene is necessary as

Technology : Production Process

• Standard detergent powder manufacturing plant consists of mixing, drying, after drying, packing and antipollution units. These units are briefly described as follows:
• Mixing unit: Linear alkyl benzene sulphonate paste is metered into a slurry preparation tank together with metered sodium silicate solution, and solid phosphates, sulphates and additives. The slurry preparation tank acts as a coarse mixer. Here lumps are broken down and air pockets are eliminated. Materials after blending are conveyed to an ageing vessel.
• Mixing is carefully controlled to prevent aeration of the slurry. Feed slurry passes through a coarse filter, homogenizer and fine filter. Deaeration of product is carried out if necessary. The slurry of constant solid content and viscosity is ready for spray drying. This detergent slurry is heated and transferred to the top of the spray drying tower by high pressure pump.
• Drying unit - Free flowing, non dusty, non caking detergent products in bead form are produced by Spray Drying mostly in counter current flow using pressure nozzle atomization. The mixed slurry is sprayed through nozzles (under pressure) to create small droplets. Inlet temperatures vary according to product and up to 400^oC inlet temperatures are used for some detergents. Hot air from direct fired air heaters is used for Spray Drying. Exhaust high efficiency 38-9 cyclones / bag houses are used to control emissions and maximize product recovery are part of the spray drying plant. The dried detergent powder is taken out at the bottom of the tower, and is transferred to the sieve by belt conveyor and air lift equipment.
• After drying unit  - The dried detergent powder collected from the bottom of the spray tower is pneumatically conveyed to the product silos after sieving. Here filtered atmospheric air is used as the cooling & conveying media. Dense phase conveying systems are normally preferred.
• After the granules have been cooled, heat sensitive ingredients, which are not compatible with the spray drying temperatures (like bleach, enzymes and fragrance), are added.

Packing unit : The final product is packed here. Detergent powder is fed into the packing machine from baggies.