Question

In the Pt Lisas industrial estate ammonia plant, conditions double block and bleed systems are needed to prevent product contamination or where it is necessary to remove essential equipment from service for cleaning or repairs while the unit continues in operation.

Where double block Valves are used, a NPS 3/4 or larger bleed Valve should be installed between the block Valves.

Review the manufacturer’s information/specification for a block & bleed regulating unit (control valve) shown below in Figure 1 with reference to standard terminology and data provided below to evaluate a control valve required for the application. Specify block & bleed valve by parts – body (type, size, trim, number of ports, flow characteristics, type of shutoff, body & trim material, type of connection) (P2.3

a) what is ammonia

b) explain block and bleed vales

c) assume state of ammonia

d)comparison of linear and rotary valve

e)list four types of valves and compare

Answer 1