Naveed Ramzan

SELECTION OF A SUITABLE METHOD FOR THE SYNTHESIS OF COPPER NANOPARTICLES

Various methods for the synthesis of copper nanoparticles employing chemical, physical and biological techniques considering bottom-up and top-down methods synthesis have been studied. The properties of copper nanoparticles depend largely on their synthesis procedures. The results from various investigations performed by di®erent scientists using these methods have been summarized. The applications, characterization techniques, advantages and disadvantages of each synthesis method are also the point of discussion. A detailed study of the results reveals that chemical reduction methods are most suitable for the synthesis of copper nanoparticles. Chemical reduction of copper salts using ascorbic acid (Vitamin C) is a new and green approach in which ascorbic acid is used both as the reduction and capping agent. This approach is the most e®ective

A green method for the synthesis of Copper Nanoparticles using L-ascorbic acid

Chemical Reduction technique was employed to prepared highly stable and dispersed Copper nanoparticles using L-Ascorbic Acid (Vitamin C) as reducing as well as capping agent. In this technique, cupric chloride was used as precursor. The effects of different molar ratios of L-Ascorbic Acid on the concentration and size of copper nanoparticles were studied. The Copper nanoparticles were characterized by X-Ray Diffraction, Atomic Absorption Spectrometry, and Fourier Transform Infrared Spectrometry. The results show that with the increase in the molar ratio of L-ascorbic acid the concentration of Copper nanoparticles were also increased. The average particles size of copper nanoparticle was found in the range of 50-60 nm. The product was kept in ambient conditions for three month but no sedimentation or separation was observed. The use of ascorbic acid makes the process a non-toxic, cost effective and environmental friendly green method.

Ni(II) REMOVAL BY BIOSORPTION USING FICUS RELIGIOSA (PEEPAL) LEAVES

ABSTRACT The pollutant binding capacity of acid treated Ficus Religiosa (Peepal) leaves was investigated in a batch system under varying conditions. The results indicate that sorption equilibrium was established in about 60 minutes with equilibrium capacity of 6.35 ± 0.54mg/g. The Ni(II) sorption is highly dependent on pH and maximum removal was observed at pH 7 above which metal started to precipitate. It was also observed that sorption of Ni(II) decreases with increase in temperature. The experimental results were analyzed in terms of Langmuir and Freundlich isotherms. The Freundlich isotherm model fitted well to data with 0.94 regression co-efficient (R 2 ). Evaluation of experimental data in terms of biosorption kinetics showed that the biosorption of nickel (II) on biomass followed pseudo-second order kinetics. The results showed that biosorbent is an attractive low cost alternative for the treatment of wastewaters containing lower concentrations of Nickel. Keywords : Ficus Religiosa

Methodology for the generation and evaluation of safety system alternatives based on extended Hazop

Process safety is paramount in the secure and viable operation of any chemical process plant. Many techniques and methodologies have been defined over the years to undertake steps that will ensure a safe operating environment at a chemical facility. However, until now, process simulation has found very little or no use in safety‐related studies. This article introduces a systematic framework based on Extended Hazop (that is, Hazop supported by disturbance simulation related to process malfunctions.) The Extended Hazop differs from standard Hazop in documenting results, classification of frequency and consequences of process deviations, and application of a risk potential matrix (Hazop decision matrix). In this article, the Extended Hazop method is explained. Application of this method will be demonstrated in a separate article.

Implementation Issues of PSM in a Fertilizer Plant: An Operations Engineer's Point of View

In this article, guidelines are provided for implementation of the elements of process safety management (PSM) such as management of change (MOC), process hazard analysis (PHA), incident investigation, emergency planning, and response. The role of mechanical integrity, operating procedures, compliance audits, pre‐start‐up safety review, contractors, training, work permits, and process safety information for implementation of the PSM in a fertilizer plant are discussed. Implementation of MOC is an important step for the adoption of PSM standards and a necessary condition for internal and external audits of the plant. There are many issues linked with implementation of PHA like plant modifications, shut downs, and production losses as well as the behaviour of the design engineer whenever modifications are required. Consequence analysis, an evaluation of an incident in terms of its effects on environment, equipment, and people is of great help. Incident reporting for a company can be improved by ensuring confidentiality and not exposing the reporting person. Improvement in the operating procedures and preserving mechanical integrity of the process plant are necessary conditions for the implementation of the standards. Internal and external audits of the company are the most important part of the PSM implementation. In general, the PSM implementation requires much effort and time but pays off well if implemented fully.

Application of extended hazop and event-tree analysis for investigating operational failures and safety optimization of distillation column unit

Process safety has a high priority in the chemical industry. And the distillation is the most widely used unit operation in the chemical‐processing industries. The use of dynamic simulation for safety‐related studies for a distillation column has great significance for the study of operational failures. In this article, a systematic framework based on Extended Hazop and Event‐tree analysis is applied to a distillation column unit of a chemical plant. Over pressuring of column is studied and different safety system alternatives are generated and evaluated using Event‐tree analysis. This article describes the details of an effective method used for a distillation column but it can also be used for other hazardous unit operations.

Multicriteria decision analysis for safety and economic achievement using PROMETHEE: A case study

Process safety and cost are major considerations during the design of process plant and its projected operation. It involves critical decision making for the best choice. A cost‐benefit analysis is usually carried out to facilitate this activity. However the final decision rest with the engineer. In this article, a systematic procedure based on multiobjective decision analysis PROMETHEE (Preference Ranking Organization Method of Enrichment Evaluation) has been demonstrated for its usefulness through the case study of a distillation column unit. This decision analysis includes: (1) generation of alternatives for safe design, (2) analysis of alternatives based on extended HAZOP methodology for hazard identification and alternatives generation, (3) the economic module for carrying out both fixed and operating cost estimates and extended cost calculations e.g. risk cost. Aspen Plus™ was used to develop the computer model. The dynamic simulation of the process was carried out in Aspen Dynamics™ followed by the economic analysis module developed in visual basic. It has been demonstrated through the case study that significant cost savings can be achieved through prevention of incidents, injuries, loss of production, operational failures, and reduced maintenance costs.

Simulation of circulating fluidized bed gasification for characteristic study of pakistani coal

Abstract A process model for turbulent pressurized circulating fluidized-bed coal gasifier is created using ASPEN PLUS software. Both hydrodynamic and reaction kinetics parameter are taken into account, whose expressions for fluidized bed are adopted from the literature. Various reactor models available in ASPEN PLUS with calculator as External Block are nested to solve hydrodynamics and kinetics. Multiple operational parameters for a pilot-plant circulating fluidized-bed coal gasifier are used to demonstrate the effects on coal gasification characteristics. This paper presents detailed information regarding the simulation model, including robust analysis of the effect of stoichiometric ratio, steam to coal ratio, gasification temperature and gasification agent temperature. It is observed that, with the increase in the flow rate of air, the components hydrogen, carbon monoxide, carbon dioxide and methane reduce, which causes the Lower Heating Value (LHV) of synthesis gas (Syn. Gas) to decrease by about 29.3%, while increment in the steam flow rate shows a minute increase in heating value of only 0.8%. Stoichiometric ratio has a direct relationship to carbon conversion efficiency and carbon dioxide production. Increasing the steam to coal ratio boosts the production of hydrogen and carbon monoxide, and causes a drop in both carbon dioxide concentration and the conversion efficiency of carbon. High gasifying agent temperature is desired because of high concentration of CO and H2, increasing carbon conversion and LHV. A high gasifying agent temperature is the major factor that affects the coal gasification to enhance H2 and CO production rapidly along with other gasification characteristics.

Performance analysis of cation and anion exchangers in water treatment plant: an industrial case study

Performance analysis of cation and anion exchangers in water treatment plant: an industrial case study Performance of cation and anion exchangers was evaluated by carrying out breakthrough analyses of pH, conductivity, free mineral acid (FMA) and various dissolved solids for an industrial water treatment plant of 700 gpm capacity. The breakthrough curves showed no leakage of calcium, magnesium and chloride throughout the operating period of the train, however, they indicated the early leakage of sodium, potassium, sulphate and silica. The operating/breakthrough capacity, total capacity and degree of column utilization were determined. The column utilization was found to be 67.85%, 38.93% and 16.78% against the design values of 90%, 85% and 85% for cation, primary and secondary anion exchangers respectively. The operating time of the water treatment train was significantly increased by achieving adequate capacity utilization of secondary anion exchanger. The low capacity utilization of secondary anion resin due to early silica slippage, has been discussed in the paper.

Incident investigation in Pakistan's fertilizer industry—Common safety management system failures and issues

The learning from operational incidents plays a key role in improving the performance and safety of the chemical process plants. In this article, the incidents occurred during January 2011 to April 2012 in different sections, that is, Ammonia, Urea, and Utility Units of fertilizer sector in Pakistan have been analyzed using Why Tree analysis. The aim is to identify the failures in the safety management system to prevent the incidents. One thousand and fifteen, root and contributing causes identified in investigations strongly assert that improvement in safety management systems could have prevented or mitigated the intensity of many of the occurred incidents/accidents. The flaws in mechanical integrity, maintenance procedures and operating procedures, and job risk assessment are the most common recurrent as root cause failures of safety management system.