Long distance transport pipeline systems
Dense slurry is a thick suspension of fly ash in water with has higher density and viscosity than lean slurry. Due to the higher density higher pump heads are required for transporting DS in pipelines than a Newtonian fluid, such as clean water or lean slurry. The resulting increase in power consumption is more than offset by the less volume pumped if slurry density is kept at optimum. Dense slurry may hold the larger particles of bottom / bed ash in suspension which helps to significantly reduce pipeline abrasion. When the dense slurry plant is shut down its vessels and pipelines must be drained and flushed with clean water.
The DS transport and distribution pipelines are of simple carbon steel pipes sized to allow sufficient transport velocity to avoid settling of the slurry and maintain turbulent flow.
The pipeline starts downstream of the DS distance transport pump discharge flange can be isolated by remote actuated shut-off valves. The pipeline is equipped with the necessary drains. The pipeline is constructed of sections according to the terrain topology. Each section can be separately drained to empty the line after flushing to avoid freezing, for example.
The optimum density of the Circumix DSS allows to use pipes and valves of low pressure ratings. The pressure rating of the pipeline components is in accordance with the maximum allowable head of the pump train. As an example, the pressure rating is 40 bar if the discharge distance is around 6 – 8 kms (ca. 4 – 5 miles) and the geodetic elevation is not too much.
As the proper sizing of the pipeline is essential for the reliability, wide control range and low lifetime costs of the dense slurry system, we reserve the right to specify the main parameters for our own discretion. These project – specified pipe selection instructions are handed over in the basic design phase. In order to duly support the detailed design of the long distance transport pipeline beyond our scope of design and supply, a guideline of typical pipeline routing solution is also handed over to the Client.