Fired heaters standards

Increasingly, newer fired process heater installations are adding more fuel-air combustion controls and safety instrumentation systems. However, the decision on the extent of fired heater combustion controls, instrumentation, and safety systems to employ is fundamentally a loss prevention and risk tolerance issue, rather than a fire protection one. The following recommended practices, codes and standards apply to fired heater and dryer controls and instrumentation ... 

Standard burners typically result in NO , formation in the 0.12-0.14 Ib/MM Btu (100-120 ppmv) for fired heaters and the 0.2-0.3 range for boilers. Factors that influence this number are ... 

API 560. 2007 Fired Heaters for General Refinery Service, ANSI/ API Standard 560,4th ed., August 2007. 

API Standard 665, Fired Heater Data Sheet, was developed to minimize problems of incomplete specifications. Its five pages provide a complete check list. Information which must be defined by he purchaser is marked with an asterisk and includes such data as complete process requirements, fuel characteristics, structural design data, coil design conditions, types of headers and terminals required and site conditions. 

This example is provided for illustrative purposes only. It uses a fired heater low-pass flow SIF to illustrate various technical points. The design is not intended for use in any real application. The reader should review relevant application specific standards and technical reports to ensure that the process hazards are identified and that the design is complete. 

Cabin fired heaters inciude a tough metai sheii that surrounds a firebox, convection section, and stack. Cyiindricai furnaces use a tube-shaped firebox to transfer heat energy into a moving liquid. A box furnace has the same standard components as a cabin furnace. The burners can be arranged on the bottom or on the sidewaii. The tube arrangement depends on how the burners line up. 

A fired heater or furnace is used to heat large quantities of hydrocarbons for industrial use in a distillation system or reactor. Fired heaters are characterized by three basic designs cabin, cylindrical, and box. The basic components of a furnace include shell, refractory lining, burners, radiant tubes, convective tubes, damper, stack, and firebox. Air and fuel are proportionally balanced as temperatures in the furnace are held constant. Figure 7-12 shows the two standard symbols used for a fired heater or furnace and a boiler. 

Standard API 556 (2011) is meant for instrumentation, control, and protective systems for fired heaters and steam generators. It has been found that it btings the concepts from the ISA BMS technical report. It also covers instmmentation and control (l C) for gas-fired heaters and steam generators in refinery, chemical, and petrochemical plants. However, it includes neither heat recovery steam generators nor any guidelines for SIL. Other major standards relevant to boiler controls are the latest edition (2015) of NFPA with different application areas ... 

Heaters are vessels used to raise the temperature of the liquid before it enters a gunbarrel, wash tank, or horizontal flow treater. They are used to treat crude oil emulsions. The two types of heaters commonly used in upstream operations are indirect fired heaters and direct fired heaters. Both types have a shell and a fire tube. Indirect heaters have a third element, which is the process flow coil. Heaters have standard accessories such as burners, regulators, relief valves, thermometers, temperature controllers, etc. 

Steam is the usual heating medium, and a standard heater arrangement consists of a main heater before the circulating fan. When steam is not available or the diying load is small, electricalheat can be used. For temperatures above 450 K, products of combustion can be used, or indirect-fired air heaters. 

The first instantaneous water heaters which started appearing in the 1890s when gas or liquid fuels started becoming available, were un-pressurized. The first models had no automatic controls and vei"y limited safety features. Some early models were more efficient than standard modern gas-fired water heaters. 

Average efficiency of new gas-fired water heaters has increased from an estimated 47 percent in the mid-1970s to about 56 percent in 1999. Over the same period the efficiency of electric water heaters has risen from about 75 percent to 86 percent. Revised efficiency standards were expected to be adopted during 2000. 

The main target of a boiler is to capture the overall energy of the flue. This depends on the total heat exchanger surface, the resistance to corrosion, and the resistance to certain temperatures of raw material, for these reasons, the heat exchanger of a gas- or oil-fired water heater or combi can technically be seen as standard, low temperature, or condensing. 

---