Thursday April 26, 2018

Working with hydrocarbons and a petrochemical company

These were challenging projects. Hydrocarbons are flammable at best, explosive at worst, so all equipment and procedures had to be ATEX compliant.

The fluids themselves hold very different properties to water, especially viscosities and densities, both of which can have a very telling effect on pump performance and, moreover, make it difficult to compare to original OEM test performance on water.

We performed pump tests at three different sites, each with different characteristics and objectives:

Assessment of DRA on petroleum and diesel products

On the first site the objective was to verify the effect of the Drag Reducing Agent (DRA) on specified petroleum and diesel products. So, we tested the same pump on the different fluids with and without the DRA in each. The results were very conclusive. The petroleum product was much more sensitive than the diesel, and yielded a 67% increase in flow rate relative to a more modest, but significant, 20% increase for diesel. In addition, the specific power consumption for each product was reduced (by 22% and 20% for petroleum and diesel respectively). This was because the pump now ran closer to its Best Efficiency Point (BEP).

Crude oil transfer pump selection assessment

On the second site the objective was to establish the performance of two 1MW pumps, conveying 900m3/hr of crude oil to the Szazhalombatta refinery near Budapest. Unfortunately, the pumps were not sized appropriately and were running at 60% of their best efficiency flow rate at a maximum pump efficiency of 69%, when 82% would have been possible.

The operating company were presented with selected options for improving the efficiency of the system and also increasing their mean time between overhauls.

Mechanical and hydraulic health check of 10-stage transfer pump

The third objective was to ascertain the mechanical and hydraulic health of a 10-stage transfer pump conveying 118m3/hr of a blend of toluene and benzene. This was achieved using a mixture of vibrational analysis of the bearings and hydraulic performance testing using the thermodynamic technique.

We found that the pump was operating very closely to its OEM’s as-new condition, complementing the owner’s maintenance regime. However, there was a 19 per cent energy loss due to choosing to use a control valve to maintain the desired flow rate.

In all cases the testing and analysis work is complete. Optioneering is taking place before key decisions are made as to the best course of action. However, in every case there is now the necessary asset performance information available to allow decisions to be informed and accurate.