Distribution Pipeline Network Research Articles

Fuzzy logic control for use in in-pipe mobile robotic system navigation

This paper presents a fuzzy logic control for the navigation of a mobile robotic system in gas pipelines. The robotic system is designed for a local gas distribution pipeline network with 150–300mm diameter pipes; common pipe fittings in use are straight and bend sections, reducers and slope pipe sections. The navigation problem forms a part of the current development of a new modular and semi-autonomous vehicle system. The vehicle control and navigation technique is implemented using a two-mode controller consisting of a proportional-integral-derivative (PID) and fuzzy logic control. The PID controller is responsible for direct control of the actuators, while the fuzzy logic controller is used to evaluate as well as to define the sensor outputs such as speed, climbing angle and rate of climbing angle in order to perceive the different types of pipe environment and vehicle actions. Since the navigation problem involves a multivariable input-output (MIMO) system, a cascaded hierarchical fuzzy model configuration is used to reduce the dimensionality of the fuzzy model. The fuzzy navigation controller is thus an interlink fuzzy subsystem of the pipe environment recognition and action adjustment subsystems. Results of simulations and laboratory experiments are presented to demonstrate the ability of the control strategy. A brief description of the mobile robotic system used is presented as background.

New GTL method for lighter fractions

Natural gas is destined to become a larger part of Nigerian energy mix as the country seeks to guarantee the sustainability of its energy supply and benefit from greater energy efficiency and reduce energy-related costs. However, this continues to be a relatively slow process with large quantities of associated gas still being flared, as it has been since the 1950s. Natural gas' availability, versatility, accessibility, and more importantly its clean-burning characteristics when compared to other fossil fuels, is a substantial driver for its further utilisation in country. Nigeria is endowed with some 182 trillion cubic feet (tcf) of proven gas reserves, and that is mostly located in the Niger Delta. Nigeria's government is keen to develop local utilization of gas employing a range of available technologies. These technologies include gas to power using gas fed by transmission and distribution pipeline networks to supply combined cycle gas turbines (CCGT), compressed natural gas (CNG), gas to liquids (GTL) to supply transportation fuels, gas to fertilizer (GTF) and petrochemicals to support domestic industries, and export options involving liquefied natural gas (LNG), the West African Gas Pipeline (WAGP), and, in the future, other potentially large-scale export routes (e.g. to Europe through a Trans Saharan Gas Pipeline (TSGP). This paper reviews these gas utilization options, export potential, and government's policies that are stimulating gas investments in Nigeria.

Gas distribution network in the UK upgraded

The UK has one of the largest gas pipeline distribution networks in the world with many houses and businesses supplied direct from an extensive national grid primarily run by ex-state-owned entity Transco (formerly British Gas). Control valves designed and manufactured by Severn Glocon are currently at the centre of a major upgrade project on this network, much of it originally built in the 19th century.

A universal dynamic simulation model of gas pipeline networks

A model for simulating the dynamic behavior of gas distribution pipeline networks is developed. A new implicit integration method and a special crossing-branch method are presented. The first method can accommodate systems exhibiting both slow and fast responses and prevents numerical oscillations in the solution. In the crossing-branch method, the solution of very large systems described by sparse matrices is provided, based upon special properties of the matrix. On the basis of these methods, a universal model for simulating the network of any structure of arbitrary size is created. Examples of model testing and use are given.