Improving Performance in Indirect, Natural Gas Line Heaters 2011-01-1016
As a regulated public utility, Consumers Energy constantly struggles to lower operating costs, so that customers can enjoy competitive rates for the natural gas they consume across the state of Michigan. Elimination of line heaters altogether would be one very desirable method of reducing operating cost, unfortunately, Joule Thomson cooling, and the trouble it causes is a fact of life for the natural gas transmission and distribution utilities. Considering this, the operation of line heaters must be optimized so that operating cost can be minimized. Line heaters must be sized appropriately, and controlled so that they are large enough to heat efficiently, but not oversized. Once a heater is installed, the temperature band that it operates within must be set appropriately.
This work presents theory that, over time will improve the efficiency of the operation of line heaters within Consumers Energy. Two objectives of this work will be presented. The first objective presented is a model that can be utilized so that line heaters may be sized as efficiently as possible, and then operated at the optimum temperature. A test facility consisting of a heater, associated control and data acquisition equipment was constructed in Flint, Michigan at an existing gas regulator station. At the test facility, studies using the calculated vs. measured bath temperatures in various scenarios have been conducted in order to validate the models reliability. Based on the results, recommendations have been offered, and future work has been proposed that will improve the model as currently programmed. The second objective is to provide a recommendation to where the control point that will control the heater as efficiently as possible, by only calling for heat when required. In addition to the data collected at the test facility, data was collected from, a cross section of heaters from the 2008-2009 heating season. Significant savings can be achieved by the relocation certain installations' control point.