Waste Heat Boiler Pdf

The buildup of boiler scale is most severe in those areas in which the maximum heat transfer occurs. The gas temperature at the boiler inlet was reduced to about P from oP, which helps reduce slagging. Gas and steam pressures are psig and psig respectively. High steam purity can be obtained by using an external elevated steam drum with internals. One way is specify on the basis of the area.

Waste heat boiler deskbook

Therefore condensation of acid is avoided and hence the corrosion problems. Surface area for the smaller tube is sq it versus for the larger tube. Technology is also available to handle the emission problems arising out of these facilities. Note that a smaller shell, lesser tube count could mean a less expensive boiler though the length and the gas pressure drop could be more.

Gas Installation Technology R. The gases on leaving the boiler enter an economizer. The pressure drop may be computed as before.

The flue gases are then drawn into the waste heat boiler using an induced draft fan. Waste heat boiler deskbook Home Waste heat boiler deskbook. In mass burning systems, the waste is not processed except for removal of bulky items such as mattresses, iron and steel products. Due to the high gas inlet temperature, umberto eco foucault s pendulum pdf a screen section was used to shield the superheater from radiant heat.

More information on finned tubes and their optimization can be found in Appendix A. However the popular method is steam or water injection in the gas turbine.

Figure shows a recovery scheme and Figure an arrangement of boilers for generating steam and power from refuse. High temperature liquid phase corrosion, caused by molten alkali metal salts such as metal chlorides and their eutectic mixtures that have low melting points. Fouling inside the tubes on the other hand will also result in lower U o, lower duty and possibly increase in gas pressure drop, which can be monitored. Depending on the thickness of refractory used, the shell diameter could be arrived at. Two gas pass fire tube boiler with elevated drum for sulfur recovery application.

Interstage desuperheaters using demineralized water are widely used to keep metal temperatures low. Figure shows a boiler in a small hydrogen plant in which the flue gas stream is cooled in a water tube boiler, while the reformed gas and converted gas streams are cooled in fire tube boilers. Hence selection of fin configuration along the gas flow path has to be made with great care. Start by pressing the button below! Scheme for fresh air firing.

The ash is considered by some to be toxic and concerns on how it is being disposed of playa role in the location of the incineration facilities. This system offers more advantages compared to a combined cycle system.

The reason is the high temperature corrosion problem associated with Hcl in the flue gases, which was discussed earlier. The gas properties must be evaluated. The program also estimates the fuel input to consume all of the oxygen in the incoming air or turbine exhaust gases. By fitting the kiln with liquid and gas burners, several types of hazardous wastes may be treated.

Once this number is entered, the list of gases up to the maximum number appears on the screen, one by one. The boiler duty has sensible as well as latent heat components due to the condensation of sulfur. The steam reforming process converts a mixture of hydrogen, methane, carbon dioxide, carbon monoxide and water vapor in the presence of a catalyst. Hence a portion of the gas has to be bypassed and mixed with the cooler gases to obtain the desired exit gas temperature.

Cleaning aisles and soot blowers are provided. The first few rows are bare, followed by tubes with increasing fin density.

Waste heat recovery unit

The low Btu gas from the gasifier is fired in the gas turbine as shown in Figure and after being cleaned in a hot gas cleanup system. In addition, a mixed flow arrangement was used for the superheater with the steam exit at the cooler gas end so as to minimize the tube wall temperature. The front tube sheet is also protected by refractory. The stack could be self standing or mounted over the turning section.

They are usually found in concentrations below the Lower Explosive Limit and hence need auxiliary fuel to burn. However if the gas stream has slagging constituents as in municipal solid waste incineration plants, cleaning the boiler is easier with water tube boilers with soot blowers or rapping mechanisms.

Maximum fuel input possible to consume all the oxygen. The sizing concept for the fresh air fan is discussed later, as it affects the system efficiency. The composition of the stream must be known to determine if it needs auxiliary fuel support or excessive air. The flexibility of varying process steam and power output without wasting energy. The final enthalpy is obtained and, through an iterative process, the corresponding temperature is found.

Waste heat boiler deskbook - PDF Free Download

Additional burners are fitted in these chambers to ensure temperature level and destruction efficiency. Problems with melting glass in the bed. Determine the final temperature.


This reduces the temperature differential across the tube sheet. Sealing efficiency of a damper could be specified in two ways and it is important to note the difference.

Modular incinerators are used for small units, up to tpd. With the enclosed chart it is possible to accomplish this purpose. Flue gas analysis, molecular weight. Suitable for high gas pressures.


If there is scale formation, the tube wall temperature will be much higher as shown in an earlier example. In some plants the steam drum is made common to the flue gas and reformed gas boilers through a system of downcomers and risers.

Waste heat recovery boilers Waste heat boiler - Waste heat recovery