Keeping it clean

2nd May, 2008

Brian Davis examines the different filtration methods available to producers

There is a classic saying in hydraulic filtration circles: ‘If the liquid looks clean, it’s dirty. If it looks dirty, throw it out.’ Nevertheless, a significant number of small and mediumsized biofuel producers still rely on cheap and cheerful filtration systems.

Maintaining and improving biofuel quality is a high priority.

Impurities including fibrous materials, catalysts and other contaminants must be removed at different stages.

Efficient removal of contamination demands different filters, optimised to meet quality and endproduct requirements. Key factors to consider are the process volume, flow rate, and chemical characteristics of the materials to be removed and particle size.

Filtration systems are also dictated by whether material extracted can be recycled into the process stream or safely disposed of. Some processes are continuous, while many are batch. Biofuel producers should also bear in mind maintenance management; exposure of the process liquid during filtercleaning or replacement; and the quality and destination of the by-products.

There is also the thorny issue of cost, determined by how often filter bags or cartridges need to be replaced or whether to use clean-inplace (CIP), self-washing systems. The economics of filtration can be complex, given the need for regular replacement in a lean labour environment with few process staff on hand. Installed costs must also be balanced against operating costs.

Click here to subscribe to Biofuels International now!