Abstract
Helitherm is a passive and stand-alone solar thermal powered heating system for pipelines and vessels and is applicable for crude oil/product flow enhancement and heat tracing in above-ground installations.
Helitherm's operating principle relies upon an integrated thermal diode, which traps sunlight and retains heat. The pipeline is fully insulated and therefore heat loss is minimized and the elevated temperature maintained.
This paper specifically addresses the throughput enhancement of heavy crude oils using Helitherm technology. In order to quantify the throughput enhancement, Solar Systems has developed a computer model called Helitherm Dynamic Simulator to evaluate the pressure drop and temperature profile of a Helitherm pipeline and compare it with a bare pipeline under average sunshine conditions. This program can also be used for nighttime analysis of pressure drop and temperature profile in Helitherm and bare pipelines. This program evaluates the pressure drop at crude oil viscosity corresponding to an integrated average pipeline temperature. FEA techniques are also being developed to obtain a more accurate pressure and temperature profile.
Based on this computer model, Solar Systems has conducted several feasibility studies for oil companies around the world. Two studies, one for Petroleos de Venezuela SA and the other for Pertamina (Indonesian National Oil Company) have been discussed in detail.
For PDVSA, the existing throughput of 231BOPD will increase to 306 BOPD, resulting in a percentage increase of 32.4%.
Similarly for Pertamina the increase in throughput is from 386.4 BOPD to 452.4 BOPD, resulting in a percentage increase of 16.8%. The payback period for both projects is less than one year.
In addition to the increase in throughput under no flow (stagnation) conditions, the pipelines are maintained at a temperature higher than the pour point at all times. This eliminates the pipeline start-up problems.
Another version of the computer program (called Helitherm Static Simulator), which predicts the temperature profile of a solar heated pipeline during no flow (stagnation) conditions has been developed and validated for a range of climatic conditions.
Solar Systems Pty Ltd has analyzed the Thayfut pipeline for Petroleum Development of Oman to demonstrate the capability of Helitherm as a stand-alone heat tracing system.
Both these programs would assist a pipeline designer in evaluating the pressure drop, pipe sizing, selection of pumps, investigating pipeline start-up problems and computation of thermal expansion in pipelines.
Helitherm technology is an innovative and economically attractive alternative to the conventional electric or steam heat tracing of pipelines or utilization of drag reducing agents (DRA's) or pour point depressants.
Depending upon process requirements, this technology is specifically suited for tropical and mid latitudes. This technology is also suitable for vessels.
