Density or API gravity trim blenders are suitable for blending liquid hydrocarbons where the quality of the feedstock is not stable or varies due to inconsistent supply or product layering in tanks and the main parameter of importance in the final blended product is density.
The in-line density trim blender starts to produce the final product defined by a component ratio in the recipe, but a densitometer analyzer mounted at the exit to the blend header is used to continuously optimize the quality of the final product during the batch.
Product quality is maintained during the batch by the closed loop control between the flow signals from the field equipment (flow meters, pressure, temperature sensors and densitometer) and the control signals from the controller back to the field equipment. The accuracy of the blender is determined by the accuracy of the density measurement and control system. All blenders are designed to minimize heating, noise and other process variations, which can affect density measurements.
The field equipment
The field equipment (valves, meters and densitometer etc) enable the components to be simultaneously metered into the lend header to produce the final blended product. Products normally exit the blend header through a mixer to ensure that a homogenous product is delivered at all times. This also provides an ideal location for an automatic sampler. The field equipment for every blender is selected to ensure minimal pressure drop and maximum reliability.
The control system
The real-time control system monitors the outputs from the field equipment (flow rates, etc), performs calculations for meter linearization, temperature compensation, etc. and feeds back appropriate control signals to the field equipment to maintain the blending process within the required parameters (i.e. closed-loop control).
The controller has unique self-learning control algorithms that instantly respond to changes in process conditions or feedstock quality and the components are continuously measured and adjusted during the batch to ensure optimum quality and minimum give-away. Blended products are volume corrected to standard conditions using API 2540 / IP 200. Loading and blend documentation can be automatically produced in volume or mass units by the controller.
Sensia's density trim blenders are designed to ensure consistent quality throughout the batch even during tank changes, feedstock starvation, loss of power or the unlikely failure of a system component. All of our density trim blenders are supplied fully skid mounted, piped, wired and tested ready for installation at your site and guaranteed to perform to your specifications.