Design of Pilot Plant Based on New Blasting Explosives Developed From Decanted Trinitrotoluene (TNT)

Abstract

This work presented in the thesis pertains to the design of a pilot plant based on new blasting explosives developed from decanted Trinitrotoluene (TNT). Disposal of life-expired and unwanted munitions is a great challenge across the globe. In the past, these unserviceable explosives were disposed of through conventional disposal techniques such as Open Burning/ Open Detonation (OB/OD), sea dumping, underground demolition, incineration and biological degradation. Production of poisonous and toxic gases such as NOx, COx, etc. during these disposal techniques have always been a great concern for Environmental Protection Agency (EPA). Besides, labour cost for the preparation of disposal pits, fuel requirement for shifting of explosives to munition disposal sites and use of large quantities of serviceable explosives during disposal of these unwanted munitions makes these techniques most uneconomical, unsafe and unfriendly for the environment. In order to curtail all these practices, decanting of explosives through decanting plant were carried out for different munitions. All decanted explosives, particularly decanted TNT, were disposed of further through open air burning. In the present research work, efforts have been made to reutilize the decanted TNT. For this purpose, various ingredients such as oxidizers, stabilizers and additional fuels have been added to the decanted TNT to convert it into viable blasting explosive compositions. Laboratory scale experiments using decanted TNT and other ingredients such as calcium ammonium nitrate (CaAN), commercial grade wax and calcium carbonate (CaCO3) have been carried out to make different blasting compositions. All the newly formulated compositions were characterized through different analytical techniques such as Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Thermogravimetry/ Differential Thermal Analysis (TG/DTA) and Fourier Transform Infrared (FTIR) to study their morphological and thermal cum kinetic properties. Simultaneously, Horowitz and Metzger method is used for calculation of activation energy (Ea) and enthalpy of different samples. Once all compositions were certified for their future use, velocities of detonation (VOD) measurements were conducted. Besides, stability tests, the density of all these compositions were also measured. In order to translate the laboratory scale compositions into useable blasting explosives, a pilot scale plant has been designed using PTC-Creo Parametric 3D modeling software. Similarly, simulation of the design was carried out through Aspen Plus® V8.4 simulation software. Based on the successful simulation and design results, a state-of-the-art, safe, feasible and environment friendly semi-automatic pilot scale plant has been fabricated and installed for the conversion of decanted explosive into blasting explosives for civil and military applications. Main components of the plant include double jacketed mixing drums, brass-made mashing roller, 5 Horse Power (HP) motor, vertical gear box and fume discharging unit having explosives production capacity of about 10kg/ hour per batch. All the safety parameters required during manufacture, filling and formulation of explosives have been ensured to avoid any untoward situation. Functional test of this plant was performed using dummy explosive materials having almost similar compositions. Subsequently, blasting explosive samples were produced utilizing decanted TNT and other suitable ingredients. To ascertain their performance, VOD tests of all newly formulated blasting explosives have been performed. It is worth mentioning that the resultant VOD of all the samples fall between 2600-4400 m/s which makes it the most suitable product for use in blasting applications such as mining, quarrying, underwater blasting, etc. In a nutshell, the present research work not only provides an opportunity for riskfree reutilization of decanted TNT where new products are easily manufactured, cheap in cost and safe in handling; but EPA concerns regarding emissions of toxic gases into the atmosphere are also amicably addressed through reutilization of unwanted TNT that will ultimately enhance Carbon Credit Ratings of Pakistan around the globe.