Burner piping

An enclosed ground flare system has a number of key components combustion chamber, burners, piping system, wind fence, and operational and safety controls. More details about enclosed ground flare system components are given in API STD 537. 

A gas black apparatus consists of a burner pipe approximately 5 m long, which carries 30-50 diffusion burners. The flames burn in contact with a water-cooled drum, where about half of the carbon black formed is deposited. This black is scraped off and transported by a screw to a pneumatic conveying system. The gas black apparatus is surrounded by a steel box open at the bottom. At the top of it, fans suck the off-gas into filters, which collect the carbon black suspended in the gas. 

Blowing fuel lines, checking them for cleanliness, and connecting burner piping. 

Burner Pipe Testing on Cement Rotary Kilns in Industrial Operation.645... 

The utilization of the alternatives fuels through the main burner pipe of rotary kiln section is characterized by some limitation factors ... 

Figure 31.5 shows the firing system in which the PF is transported from the grinding department using the mill exhaust gas, which acts as burner pipe primary air. 

Figure 31.6 displays the firing system in which a proportion of mill exhaust gas is recirculated back to the mill inlet, thus to increase the transport air in the mill and its d5mamic classifier without increasing the primary air to the burner pipe. 

In the case of the cement rotary kiln, the fluid flow through the kiln freeboard comes from several sources such as secondary hot combustion air, combustion and decarbonation products and inleakage air. In direct firing kilns, the pulverized solid fuel is injected through the burner pipe nozzle with the external diameter in the range of 250 to 600 mm into the kiln with an internal diameter of 2.4 to 6.2 m. 

The cement rotary kilns are equipped with burners producing two type of flames (i.e., axial and divergent). The axial flames are generated by simple nonswirling burner pipe connected to a direct coal firing... 

The Fives-Pillard has developed its third generation of Rotaflam burner pipe with an enhanced adjustment mechanism, to meet any specific operafion condition required by the cement rotary kilns. 

A number of aspects must be taken into consideration when deciding to burn AF in a rotary kiln. Technical aspects, such as the heat value of different fuel types, are very important. A possible negative impact on both the clinker quality and refractory lining must also be taken into consideration. The refractory lifetime could be reduced. To avoid this, more heat and chemical resistant refractory materials should be installed as refractory lining on the external burner pipe. Economic aspects are also important and should always be kept in mind. The availability of different AF has to be considered, transportation and preparation expenses, the cost of specific equipment together with supplementary additions, plus the cost of emission control devices. 

Unitherm-Cemcon has developed the M.A.S. burner pipe in a different manner with others burner pipes existing on the market at that time. Figure 31.14 displays the burner tip with separate jackets for fluff (plastics), animal meal, and for a gas/liquid gun for the ignition... 

Total primary air available for cooling of the outer burner pipe... 

The burner pipes for cement kilns have thermal power up to 250 MWjh with length of about 10 m and weight of about 15 tons. These burners are tested only on rotary kilns either in the commissioning stage or already in industrial operation after the refurbishing of the combustion equipment. 

Reduction of amount of the primary air by utilization of low NOx burner pipe and by PF sourced by an indirect firing system. 

During the experimental campaign 161 different flames were tested, generated by a generic mono channel burner pipe and two low NO scaled down industrial burners manufactured by Fives-Pillard (Rotaflam burner) and KHD (Pyrojet burner). 

The axial flames are generated by simple nonswirling burner pipe and are applied in direct coal firing system. 

In 1995, the Italcementi Group and Pillard Company, in the frame of an EU contract decided to install a low NO Rotaflam burner on 700 (m)tpd Lepol kiln at Sarche di Clavino plant located northeast of Italy the goal was to perform indusfrial festing of fhe "wide adjustable" low NO Rotaflam burner pipe in industrial operation conditions. 

Contours of static temperature of burner pipe flame. (Courtesy of Fives-Pillard.)... 

Aiite size decreases Increasing feed volume through kiln, burner pipe retraction, and increase in primary air (Brugan, 1979)... 

McKenzie, L., "A Case Study on the Effects of Burner Pipe Position and Its Effects on Clinker Microscopy," Proceedings of the 11th International Conference on Cement Microscopy, International Cement Microscopy Association, New Orleans, Louisiana, 1989a, pp. 306-322. 

In the particular case of gaseous fuels when, for technical or economical reasons, it is necessary to replace one gas by another using the same burner piping and control, several parameters, such as the heat content, burner stability, and oxidant, must remain unchanged to ensure safe interchangeability. The Wobbe index (WI) expressed in MJ.m is used especially to evaluate the interchangeability of two gaseous fuels with respect to mass and heat flow rate. It is defined as follows ... 

We have already discussed under practical stoichiometry how the air requirements can be estimated based on the fuel composition (ultimate analysis). The primary and secondary air requirements for combustion of pulverized coal or coke are best estimated by mass and heat balance at the mill. In Appendix 6A we show a calculation taken from Musto (1997) for the primary and secondary air required for coal pulverizer with 4.5 metric ton per hour (10,0(X)lb/hr) coal feed rate at initial moisture of 15 percent which is required to be ground and dried to 2 percent with a 200 HP mill. In order to estimate the actual primary and secondary air, one has to make some estimation of the evaporation rate, the amount of gas entering the coal mill, and the bleed air required so that the quantity of air that should be vented from the hood off-take can be properly estimated. It shows that for a take-off gas temperature of 315°C (600° F) and vent gas temperature of 76°C (170°F) and allowing ambient air infiltration of 10 percent at 15°C (60°F) the primary air will be about 22 percent of stoichiometric air and 21 percent of total air. The remaining air (about 79 percent) will be the secondary air. With this information we can size a burner using a burner pipe diameter based on a Craya-Curtet parameter of choice bearing in mind the conditions that ensure the desired jet recirculation patterns described in Chapter 3. 

A pyrolysis furnace, shown in Ediibit 7-24, has btxh wall- and floor-mounted burners. Hie wall-mounted burner piping can be (grated fix>m the firing plat-... 

---