A Brazilian biodiesel plant uses the transesterification of soybean oils with the methanol and sodium methoxide catalyst excess to convert these oils into alkyl esters and glycerin. Hydrochloric acid solution is injected in the piping to neutralize free NaOH and reduce saponification of oils. After the hydrochloric acid solution, several failures of pipelines of AISI 316L and 904L steels were registered. The objective of this work is to study the austenitic stainless steel corrosion observed in the downstream piping the hydrochloric acid injection, applying computational fluid dynamics and to evaluate pH and chloride profiles using different geometries for the acid solution injection in order to avoid or mitigate the corrosive attack. The obtained results showed a good agreement with in situ observations of the pipe degradation. All the studied geometries presented evidence of a weak mixture between the polar and non‐polar species, even under turbulent flow. The elbow geometry is more effective to reduce the local corrosive attack compared to two other simulated geometries.

The neutralization of catalysts with hydrochloric acid is an important step in a biodiesel process which generates steel corrosion due to the decrease in pH, and the addition of chlorides in the medium. Other factor responsible for corrosion and consequently failures is the poor miscibility between biodiesel and acid water generating a heterogeneous coverage of the surface of the pipelines and equipment by biodiesel and acid water, presence of galvanic cells and localized corrosion. In this paper, corrosion failures of AISI 316L and 904L austenitic stainless steels (SS), and of SAF 2205, 2507 duplex SS in a biodiesel plant were identified and studied. The low pH, presence of chlorides, high thermal input in welding, temperature gradient and mainly proximity to the acid injection site play the major roles in corrosion which generate the studied failures. Corrosion failures occurred in pipes transporting biodiesel and acid water, in a spool of acid water injection, in a static biodiesel mixer with acidic water, in a cylindrical decanter vessel, and in heat exchangers.

El objetivo de este trabajo fue establecer la influencia que ejerce la granulometría del lecho del río, la forma de la pila de un puente y los parámetros hidrológicos en la profundidad de socavación, a partir de un modelo físico. Para el desarrollo experimental se empleó un suelo granular proveniente de río al que se le realizaron ensayos de laboratorio para determinar la distribución del tamaño de las partículas, empleando materiales cuya clasificación, según el sistema unificado de clasificación de suelos (USCS, por sus siglas en inglés) es SP (arena mal gradada), SW (arena bien gradada), SP-SC (arena mal gradada con arcilla). Adicionalmente, se realizó un análisis estadístico con el fin de determinar las diferencias significativas entre cada una de las variables y su influencia en dicho proceso. Se encontró que existe una fuerte relación entre la forma de la pila, el caudal y la granulometría, con las características hidrodinámicas del flujo cuando pasa por las pilas, así como en la profundidad de socavación.

Human Resources allocation is a crucial factor for success in multi-project companies. It should consider the quantity of professionals needed to develop the project and the amount of time these professionals can dedicate to it. Companies where the core business is engineering design, software design or research and development projects, usually need a variety of specialists and the allocation of these workers on the projects can be done by a simulation of the process aiming to obtain better system performance. This work makes an analysis of sizing and allocation of human resources on design processes, proposing a simulation based method to improve it. An application to onshore oil well design process for a petroleum company was made, generating a model that represents the amount of professionals needed according to a given demand. After that, some scenarios were simulated aiming to improve the system performance metrics. Through the proposed method, the process was analyzed, identifying some bottlenecks and improvement points related to downsizing and deadline accomplishment. The simulated scenarios have shown that an organization modification through centralization of well engineering offices could reach these goals.