Operating costs reduced and disposal costs eliminated
Singapore, December 2014 – A well-known pharmaceutical manufacturer in Singapore has reduced its operating costs for exhaust-air purification significantly since Dürr modernized its Ecopure RTO exhaust-air purification system (regenerative thermal oxidation). Solvent-laden waste liquids are now incinerated. The heat generated during this process is utilized, lowering primary energy demand by around 50 % and eliminating costs for the disposal of waste liquids.
Ten years ago, Dürr delivered an RTO system to the Singapore plant made of extremely corrosion-resistant stainless steel. It was used to purify up to 25,000 Nm³/h of solvent-laden exhaust-air mixtures generated during the production of pharmaceutical products. Two oil/gas-fired combination burners provided the necessary incineration temperature in the combustion chamber.
The waste liquids requiring disposal are very different in their composition and have high fluctuations in calorific value. They can also contain varying amounts of water. The customer specifications for the modernization of the RTO system stated that all waste materials should be completely disposed of in the system.
Following a feasibility study, Dürr fitted two additional liquid burners. These ensure that the energy contained in the solvent-laden waste liquids is fully utilized for the operation of the exhaust-air purification system. The special burners, which Dürr has developed itself, inject the solvent/water mixture directly into the combustion chamber, where it is incinerated at temperatures of around 820 degrees Celsius. The solvent-laden residues largely replace natural gas as primary and/or auxiliary energy during operation.
Auxiliary energy is only used to bring the system up to operating temperature or to incinerate mixtures with a very low solvent content. The use of the solvent/water mixtures in the RTO system eliminates disposal costs.
To ensure that the RTO system would only be shut down briefly during assembly and commissioning, Dürr pre-mounted as many elements used for the modernization as possible. To complete the project, Dürr dismantled the fuel oil part of the existing combination burner, as natural gas is now exclusively used as a primary fuel.