In high pressure and high temperature processing equipment a need exists to reduce the pressure after the processing and before output of the processed product. For this purpose various pressure reduction devices in the form of valves exist with properties making these resistant to the high pressure and temperatures. By the terms high pressure and high temperature it should be appreciated that the highest pressure will normally be above 150 Bar and the temperature will be above 250° C. The temperature of the processed product may be lower at the pressure reduction location due to a desire of recycling the heat to the early stages of the process.
When reducing the pressure in such processes extensive wear of valve parts, i.e. the valve and the seat, is observed due to the high velocities in the valve in order to provide the required pressure reduction. The wear is further increased when processing materials with a content of abrasive particles. Using more valves in order to allow lower velocities will dramatically increase the cost of the processing equipment and will not totally eliminate the problem of wear.
Hence, an improved pressure reduction device and a method would be advantageous, and in particular a pressure reduction device and a method that provide for a more efficient pressure reduction and/or are less prone to wear from high flow velocities of processed fluids with abrasive components.