Question

List the four common parameters that affect the optimisation of a pumping system. PLEASE PRINT THE SOLUTION IN NEAT SCRIPT

Answer 1

1.Competing Effects of Initial & Life Cycle Costs

Initial, energy and maintenance costs depend directly on the diameter of the pipework and the components in the pipework system. The pipework diameter is selected based on the following factors:

• Economy of the whole installation (pumps and system)

• Required lowest flow velocity for the application (e.g., avoid sedimentation)

• Required minimum internal diameter for the application (e.g., solids handling)

• Maximum flow velocity to minimize erosion in piping and fittings

• Plant standard pipe diameters

Increasing pipe run size will increase some costs while decreasing others. Thus, an optimum pipe run size may be found based on minimizing costs over the life of the system.

2. The Optimal Operating Point

For every pump system, there exists an operating point that achieves the lowest cost option. This concept is known as the optimal pumping system operating point (OPSOP). The pump designer has significant influence over the operating point and attempts to move the design towards the OPSOP. However, the vast number of uncertainties associated with actual system requirements, equipment characteristics and how the system is operated and degrades make it difficult to identify this operating point and impossible to achieve the optimum state.

3. How Pumping Systems Change Over Time

The conditions that exist at initial start-up of a pump may change over time due to passive or active influences. Table 1 lists some of the passive and active influences that can change the pumping system in ways that can have serious consequences on the pump’s operation. A change in the pumping system can affect the pump’s flow, efficiency, power consumption, maintenance needs, and useful service life. Therefore, it can be advantageous to design a flexible or resilient system that can adapt to varying conditions over time.

As the system ages or operational requirements change, the head generated by the pump may need to increase. If the pump impeller was selected at less than maximum diameter, the pump head may be increased by substituting a larger diameter impeller. This will increase the power requirements of the pump, so consideration must be given to the cost effectiveness of specifying an oversized driver for the initial duty.

4. Control Scheme Optimization – Commissioning the                Pumping System                                                                                           

Take great care in defining the control limits and parameters of a pumping system during the start-up phase to ensure that once set into motion, it will operate within the limits defined by the designer and equipment manufacturers. In particular, the

following parameters should be closely monitored during

commissioning:

• Liquid levels;

• Speed range;

• Verification of flow and pressure;

• Control device parameters; and

• Variable-speed drive/system control options.

Learning how to design better new pumping systems and to optimize existing pumping systems are the challenges that future engineers will face. Considering the rising costs of energy and the pressing need to address climate change, industrial plants are looking for new ways to lower operating costs and reduce greenhouse gases. Helping management understand the financial justification for pumping system optimization is necessary for project approval.