Low shear flow conditions of fluid transport is relevant topic for various industries and diverse applications within these industries. In some cases high shear flow conditions reduce efficiency of the process equipment, in others - it is critical to the quality of transferred products.
The low shear alternatives to the conventional equipment are the straightforward and cost effective solution in many cases. Some examples of low shear target applications are presented here.
Shear forces acting on the fluids passing through the valves and pumps in oil production site cause droplet break-up and emulsification. Shear in itself is not necessarily a problem and a certain level of shear can even be required, either to promote coalescence or enhance gas-liquid separation in the event of foaming. However, too much shear has a negative influence on separation efficiency. The philosophy of low shear production is to focus on the causes to separation problems instead of dealing with its consequences.
Produced water and wastewater usually contain variable amounts of dispersed and dissolved oil, chemicals, residuals and solids. Many countries have introduced environmental regulations for discharge limits of produced water/wastewater disposal. Therefore, before contaminated water can be discharged, it has to be routed to the water treatment facilities in order to achieve the required level of purity. For better separation of the contaminants low shear pumps are recommended when dealing with produced water.
Mechanical degradation of polymers is a well-known technical challenge in the petroleum industry. Applying low shear technologies to polymer flooding recovery method will reduce the level of degradation of polymer solution. This would ensure favorable mobility ratio between the displacing and the displaced phases in the reservoir. As a result, improved sweep efficiency can yield significant amounts of additional oil recovered.
Emulsions present a certain challenge when needed to be sampled. It is important to ensure that representative samples are obtained. Inadequate procedures and/or equipment may give false impressions of a sampled fluid. When dealing with emulsions care should be taken with regards to low shear operation to obtain the representative samples.
Separating the microalgae from the culture fluid remains a major challenge to industrial scale algae farming, mainly due to the small size of the algal cells and relatively dilute cultures that require the processing of large fluid volumes. The initial harvesting step is not only costly, but also affects following processes. Certain types of microalgae are sensitive to shear forces. Therefore, combination of low shear pumps and hydrocyclones is an attractive alternative, which may reduce overall costs of the harvesting process.
During biodiesel production fluid emulsification takes place. Small scale processes can utilize simple settling tanks in order to deal with emulsions. An industrial production process, though, would require more efficient methods. Utilization of hydrocyclones accompanied by low shear pumps can effectively purify the biodiesel. Low cost operation of a hydrocyclone can also make biodiesel more competitive compared to the petrodiesel.