JPS6060187A - Method for operating tubular heating furnace - Google Patents

Abstract

PURPOSE:To reduce fuel consumption during high-temperature operation, by forming a heating tube of a tubular heating furnace from a material having high heat resistance, preheating combustion air with exhaust gas from the tubular heating furnace and feeding it to a combustion chamber of the heating furnace. CONSTITUTION:A heating tube 3 of a tubular heating furnace 1 such as a naphtha cracker for an ethylene plant, which is used for heating a fluid within the tube at 900-1,100 deg.C, is constructed with a material having high heat resistance such as ceramic. Air drawn through a pressure fan 12 is preheated to 600- 1,100 deg.C in an air preheater 9, fed to a burner 4 and atomized together with fuel 5 into a combustion chamber 2. The resulting combustion gas heats a fluid to be heated in the heating tube 3, passed through an exhaust gas duct 8 and the preheater 9 and discharged through a stack 11. By passing the exhaust gas of the combustion furnace through the preheater 9 to preheat combustion air, fuel consumption can be reduced.

Description

[Detailed description of the invention]

The present invention relates to a method of operating a tube-type heating furnace such as an ethylene plan 1-free cracking furnace that heats a fluid in the tube to 900 to 1100°C. Conventionally, in tube-type heating furnaces for heating high-temperature fluids, heat-resistant VF steel has been used for the heating tube, and its maximum operating temperature is approximately 110℃.
It is 0°C. On the other hand, in the ethylene plan 1 to Kawanafuri cracking furnace, the pipe fluid temperature is approximately 860°C, the thermal flow rate is approximately Go, 0
The tube wall temperature reaches 1050-1100°C. In this furnace, the higher the temperature J and the hot outlet flow rate of the pipe exit fluid, the higher the ethylene yield.
0°C, heat flux rate 100,0OOK can/m”l)
In the case of r, the pipe wall temperature reaches 1300°C, and heat-resistant cast steel pipes cannot be operated because their heat-resistant strength decreases. Here, if a material with heat resistance and strength such as ceramics is used, it is possible to raise the tube wall temperature to 1400 to 1500°C. However, in this case, the temperature of the combustion gas in the combustion chamber becomes as high as 130°C (1-1800°C), so the amount of quenching group increases by about 1.4j8. An object of the present invention is to reduce fuel consumption characteristics when operating at high temperatures in a tube heating furnace. In this method, the heating tube is made of a material with high heat resistance strength, and the combustion air to be supplied to the combustion chamber of the tube heating furnace is heated to 600 to 1 with J gas of the type heating furnace.
By preheating the air to 1,000℃ and then supplying the preheated combustion air to the combustion chamber, the temperature of the fuel at the pipe outlet can be increased while maintaining the same level as the conventional fuel temperature. (
It is an IC device that allows you to increase the power consumption. Preferred implementation 1ζ1 of the method for manipulating the Type 75 heating furnace according to the present invention is described below with reference to the drawings. In the heating furnace main body, 11 combustion chambers 2 are formed in the heating furnace main 14.1.In the combustion chamber 2, there are 414 heating chambers 3 made of a material 1 having high heat resistance and strength such as Hiramix. A large number of bars 14 are installed at the bottom 41 of the combustion chamber.
and combustion air supply 6 are connected. Combustion waste is emitted from the upper part of the heating furnace body 1.

7 is provided, and the exhaust gas duct ε3 is connected to this lower outlet. J
) The gas gratings 1-0 are connected to the suction fan 10 via the air preheater 9, and the air side of the suction fan 10 is connected to the chimney 11.
Connected to PL. The air supply device 1-6 that supplies combustion air to the burner 4 is
It is connected to a forced fan 12 via an air preheater 9. The air preheater 9 is made up of, for example, a large number of heat exchanger tubes, and allows combustion air to flow through the heat exchanger tubes so that the air preheater 9 is heated outside the heat exchanger.
l Flow IJI gas 1. In this case, the heat transfer tube is made of Hiramix 4, which has high heat resistance and strength.The room temperature air sucked from the air 11 pusher 12 is preheated by passing through the air preheater S. The air is supplied from the air supply duct to the burner 4, and from the fuel supply chamber 5 (S) is injected into the combustion chamber 2 and becomes combustion gas.
Noteka! Heat the heated fluid in 'r'i 3'!
The exhaust gases 1 to 8 are discharged from the chimney 11 through the air preheater 9. 'j''j+ jl,jD temperature of the heated fluid is 900~
To achieve a temperature of 1100°C, it is necessary to keep the temperature of the combustion gas in the combustion chamber 2 at 1300°C (1°C). Alternatively, if air preheated to nearly 500°C is supplied, fuel consumption will increase, but the Jll after combustion will increase.
Combustion air is passed through the C1 air preheater 9 to 600~
Since it can be preheated to 1100°C, fuel consumption can be reduced.In this case, the air preheater 9
The temperature of the internal heat exchanger tube is 90 to 1400℃ (the upper back is made of a material with high heat resistance and strength (11). Figure 2 shows the temperature of the combustion air This is a graph showing the relationship between preheating temperature 'a and combustion chamber efficiency η1e, when the fuel is IQ, 950CaA/
1<9, excess air is 10%, combustion air is 17.5K (
The combustion chamber efficiency when 1/Ko - fuel is shown as (2), and the combustion chamber efficiency can be calculated using the following formula (d). Assuming that . is held constant, the higher the combustion air preheating temperature ( ), the higher the efficiency of the high culm combustion chamber. (jil
1. The efficiency is 8 to 20% at +500°C (7 degrees, but it is possible to increase the efficiency to about 25 to 4096 degrees by preheating to 600 to 4096°C as in the present invention) Next, we will increase the fuel consumption (m) by 100 in the case of conventional operation with combustion gas of 1200℃ and 411℃ without preheating the combustion air (conventional example 1). If the temperature force of 1/l (1(1') is 10η1 μ, then (
Combustion air was supplied to conventional example 2) and Jζ′) of the present invention at 60%
The combustion chamber heat ratio η and the combustion resistance when preheated to 0°C are shown in the table below. Table-1 The above table", S? , Y - 1G of crystal melon was heated from 1200°C to 140°C without preheating the combustion air as in Example 2.
When the temperature is raised to 0°C, the combustion chamber efficiency η decreases and the fuel consumption increases, but in the case of J3 in the present invention, the combustion chamber efficiency η decreases. The amount of fuel and fuel consumed is also the same as in the first conventional example, but it is possible to increase the temperature of the fluid in the pipe. J, Similarly, when the combustion air is heated to 400°C for 12 seconds, C, when the combustion gas temperature is 1200°C (Conventional Example 3), and when the heating temperature is raised to 1400°C (Conventional Example 4).
) and increase the combustion gas temperature to 1400℃,
Preheat the combustion air to 10°C (1°C), and the J3A combination of the present invention is shown in the table below. i' to C
-), then the same unity as in Table 1 is obtained for i! i
, (E, will be. Therefore, the combustion air will be 600 ~ 1 (1
By heating to 410° C., it is possible to reduce the internal flow temperature by 1゛ττ with the same amount of fuel consumption as in the past. As is clear from the above detailed description, the present invention provides the following excellent IC effects. (1) Pipe combustion air (exhaust gas from heating furnace 600~
By heating the fluid to 1000℃ and then heating it in the combustion chamber, the fuel consumption can be reduced and the fluid in the pipe can be heated to 900-110℃.
It can be heated to 1°C. (2) Since the heating tube is made of 14 stones with high heat-resistant strength, it has sufficient heat-resistant bullet holes even if the preheating temperature is 600 to 1000°C. (3) Conventional Motl'd! It is efficient because it is possible to raise the temperature of a single stream at a high temperature with the same cost.For example, when using a forehearth for an adult cow [Ni? ? It is possible to do C.

[Brief explanation of the drawing]

Figure 1 is a diagram showing an example of support for implementing the method of operating a high-quality heating furnace according to the present invention, and Figure 2 is a diagram showing an example of the method for operating a high-temperature heating furnace according to the present invention.
This is a graph showing the relationship between L degree and combustion chamber efficiency. In the figure, 2 is the combustion chamber, 3 is the heating tube, 4 is the burner, 6 is the active 2 air IJJ supply duct, and 9 is the air j5 heater.1 Patent applicant: Ishikawa, Shima 1m Ma Heavy Industries Co., Ltd. Agent Ten patent attorneys
Shin Kinutani AJI

Claims (1)

[Claims] J3 is a method of operating a tube heating furnace that heats the fluid inside the tube to 900 to 1100℃, and the heating tube is made of a material with high heat resistance strength.
1, and the combustion air is supplied to the combustion chamber of the tube heating furnace after being preheated to 600 to 1000°C with the exhaust gas of the tube heating furnace. How to operate a type heating furnace.