126. Accidents in chemical plants are mostly due to
127. For identical operating conditions, the pressure drop over __________ tray is the highest out of the following.
128. A perforated plate has holes of diameter dn arranged in a pitch ph. Each hole has a tube of I.D. dt passing through it. The ligament efficiency is given by
129. __________ is the determining factor for the number of bubble caps to be used per tray.
130. Pick out the wrong statement about distillation operation
131. Low pressure steam (with saturation temperature between 105 to 120°C) is usually used in the vacuum evaporators, which normally employ a vacuum of about __________ mm Hg (referred to a 760 mm mercury barometer).
132. Which of the following is the best tube material from thermal conductivity point of view alone?
133. Normal screwed fittings are used for pipes upto a diameter of __________ inches.
134. In a shell and tube heat exchanger, the clearance of the tube is generally
135. Diameter of the seive tray column is determined by the
136. Maximum acceptable total liquid gradient over a tray is about __________ mm.
137. In case of a 'thin' pressure vessel, the ratio of its diameter to wall thickness is
138. High pressure fluid in a shell and tube heat exchanger should preferably be routed through the
139. Bubble cap tray is the most commonly used tray in large distillation column, because
140. In common bubble cap distillation column design practice, riser area is approximately equal to (where, Aa = Annular passage area, and Sa = Slot area)
141. Heat transfer co-efficient, hG(Kcal/hr.m2 .°C) and mass velocity of air, G (kg/hr.m2 ) for air flow parallel to the surface in case of constant drying rate in batch drying is related as hG = 0.0176G0.8. But when the flow of air perpendicular to the surface is encountered, this equation changes to
142. In the agitators, the power required will be changed with the increase of diameter of agitator (D) as
143. Apex angle of conical heads used in the bottom heads of chemical process equipments is usually
144. Pressure drop due to pipe fittings can be estimated by the equation,
, where, Le = equivalent length of straight pipeline which will incur the same frictional loss as the fitting and D = diameter of the fitting. The value of (dimensionless) for 45° elbow and 180° close return bends would be respectively around
145. A pressure vessel is said to be made of 'thick' shell, if the ratio of its diameter to wall thickness is
146. Rate of filtrate delivery is inversely proportional to the
147. Tube side heat transfer co-efficient for turbulent flow of liquid through tubes is proportional to
148. Circumferential (hoop) stress in a thin cylindrical vessel under internal pressure is __________ the longitudinal stress.
149. The dust collection efficiency of electrostatic precipitator increases with increase in the
150. For storing hazardous chemicals in large storage tanks, the minimum safe distance between the two tanks should range between __________ times the tank diameter.