Efficiency Gains using Andrews Chillers to cool down Digesters - PowerPoint PPT Presentation

Efficiency Gains using Andrews Chillers to cool down Digesters during Maintenance periods. Dean Clayton Andrews Sykes Hire Ltd

The Role of Digesters in Waste Water Treatment . • Simply put, digesters are large vats of organic matter. Anaerobic bacteria in a digester break down the sewage sludge, producing methane gas in the process. • The methane gas is an important source of energy and is often used to produce heat and power within the works. • Combined Heat and Power (CHP) plants use the gas to produce energy.

Cooling required for Digester maintenance • The optimum operating temperature for mesophilic digesters is 32-37 ° C. • During times when Digesters have to be shut down for maintenance, it is necessary to reduce the temperature to below 20 ° C, so that gas production ceases and it is then safer to work with the sludge from inside the tank.

Planning for Digester Maintenance • The Dilemma: • Do you wait for the digester to cool down, without any further input, or do you spend money hiring Andrews Chillers to speed up the cooling. • Especially with Insulated Digesters, it can take several weeks to cool the digester down to below 20 Degrees C.

Option1: Non Intervention. Wait for digester to cool without intervention. Disadvantage of this option: •Can take several weeks, for ambient air temp to cool down the Digester. •Supply of gas to CHP plant is much reduced, additional energy would have to be sourced. •Digester out of action, interrupting flow through the works.

Option 2. Active Intervention. • Andrews Chiller Rental. • Benefits of this option: • Digester is back on line more quickly. • Gas production for CHP plant back on-stream faster and producing energy. • The cost of Chillers can be less than the value of the lost gas production during the period of down time.

Chillers Rental decision can be made on economic grounds Calculations have shown that there are economic benefits for cooling digesters rapidly down to below 20 ° C, when there is a need to take a digester off line, for maintenance. The significant cost of lost gas production for the CHP plant can be greatly reduced by temporary hiring Andrews Chillers.

Chiller Hire For Digesters Andrews Chiller Unit Biffa Waste Wanlip STW

Chiller Hire for Digesters • Chiller Installation is simple to carry out. • Temporary hoses from the Chiller unit are coupled to the In Situ heat exchanger. • Coolant fluid from the Chiller is circulated through the heat exchanger to cool the digester sludge. • Temperature quickly drops from 37°C to 20ºC.

Riverside STW Chiller Rental

Chiller Hire for Digesters • Conclusion: • Chiller Hire has the following benefits. • Digester down time is minimised. • Gas production is resumed quickly. • Cost of Chiller Hire can be less than cost of lost energy production.

Chiller Hire for Digesters Thank You. Please visit our stand if you have any questions.