International Journal of Scientific & Engineering Research Volume 3, Issue 5, May-2012
Jalpa Shah, Mr.Bharat Jain, Ms.Neerja, Shuchen B. Thakore and Gopal H Chaudhari
L.D. College of engineering, Ahmedabad –380015, Gujarat, India -390003
ABSTRACT
Cleaner production is a pollution preventive, company-specific environmental protection initiative which intends to minimize waste and emissions and maximize product output. It is also reduces energy consumption and global warming. Improvement of organization and technology helps to reduce or suggest better choices in use of materials and energy and to avoid waste, waste water generation and gaseous emissions.
JLR shows excellent performance in process of bio filtration where pretreatment of waste pretreatment of waste gases is necessary to ensure the stable operation of biofilter. JLR also found to be suitable method in high rate aerobic treatment of brewery waste waters. Gas induction reactors shows high efficiency for the removal of industrial wastes and have reliable operational stability at low investment and operating cost in processes of hydrogenation and sulphonation in dyes industries. Thus JLR and Gas induction reactor prove to be potential candidate for cleaner productions.
This paper also provides novel design of both the reactors for process of hydrogenation of edible oil. Design correlations and resulting data are presented in tabular form and design of any of these reactors can be done using this table.
Introduction
Gas-liquid reactions are frequently encountered in chemical, biochemical, pharmaceutical and polymer processing industries1. In gas-liquid operations, a gas must be effectively and efficiently contacted with the liquid to provide mass transfer2. Agitated tank is one type of the most common and important reactor widely used for gas-liquid heterogeneous reactions in the chemical industry. It provides many characteristic performances such as good mixing effect, better mass and heat transfers, etc3,4. However, the interaction between turbines and baffles requires high power consumption. Furthermore, the recovery of the unreacted gas injected through the process liquid from the bottom of the tank is complicated in the conventional agitated tanks. This problem is commonly solved by linking tanks in series or by using a compressor to recirculate the unreacted gas back to the process liquid. Both of these two methods are complex processes and may need additional accessory equipment and increase the operational costs. For improvements of conventional agitated tanks, gas-inducing impellers may be used as an advanced method for gas-liquid contacting in stirred tank reactors5. As the impeller rotates, the liquid phase is accelerated over the surface of the contoured impeller blades, resulting in the formation of a reduced pressure region. This reduced pressure region on the blade surface is connected to the reactor headspace, via a gas inlet on the shaft above the liquid level, hollow shaft and blades, and an outlet orifice on each blade (Figure 2). The pressure difference between the blade surface and the headspace produces a gas induction effect. The magnitude of this driving force depends on the impeller speed and the radial position of the orifice; gas induction commences when the pressure at the orifice falls to the headspace pressure, i.e. when the static head of liquid above the orifice has been overcome. The speed at which this occurs is known as the critical impeller speed 6.
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