Research Reality

By Winston K. Robbins, Ph.D.

Most modern refineries are run based on process models. However, underlying these engineering models are laboratory research studies. Between the lab and the refinery, "unit factors" are often applied to make research findings fit the real world. In some cases, the "unit factors" are due to local engineering requirements; however, in others, they arise from chemical limitations inherent in the research. In general, the engineering factors that are required to scale-up lab research are well recognized. On the other hand, the chemical limitations are often overlooked.

Ideally, research would be carried out by following the effects of a process on all components in a refinery stream using multiple analytical tools. Unfortunately, studies that are carried out on whole feeds can quickly degrade into analytical method development projects. As an alternative, research often turns to using "representative" model compounds, synthetic matrix oils, and established detection methods. The limitations of this approach are illustrated in the following examples that include a reality check and potential improvements that are available by using advanced characterization methods.

Lubes Processing

Shale Oil Hydro-processing

Non-Porphyrin Ni &V Compounds in Vacuum Resid

The limitations of a research study can be determined by how adequately the choice of model compounds, matrix material, and methods of detection probe the chemical reaction space. The chemical research space can be envisioned as a balance of three contributing factors (Figure 1).

 

Figure 1 - Chemical Factors in Research Studies

As shown, each of the factors may cover only a portion of the research space, and a given combination may only represent a small portion of the area of interest. It is important to recognize that all three factors bound the results. A combination of two factors may dictate the choice of the third. As a trivial example, if color is to follow a reaction of a model compound, then the matrix oil should dissolve the compound and have no color of its own.

Some of the parameters for each factor are listed below.

 

This list is far from complete. However, it provides a framework for designing or evaluating research studies. As seen in the examples, a poor choice of model compounds, matrix oil, or detection method limits the relevance of the research.

Advanced characterization methods play a vital role in maximizing the benefit of research studies. A thorough characterization of a target process stream defines the range of molecules that must be included as model compounds. The same characterization can identify a composition that meets the solvency of the matrix oil and compatibility with analytical measurement methods. Future articles will expand on the framework described above.