Technical modification and effects of heating furnace waste heat recovery system
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This post was last edited by Final Fantasy on 2010-7-17 06:57 Equipment: Heating furnace air preheater reasons: The heating furnace is one of the main equipment in the refining and chemical plant. Since the desulfurization effect of the heating furnace fuel is not very satisfactory, the air preheater of the heating furnace is corroded, leaked or blocked due to flue gas dew point corrosion. The air preheater cannot be used normally, and the thermal efficiency of the heating furnace cannot reach the design value. It has become a large energy consumer and cannot achieve the purpose of energy saving and emission reduction. Please share with students based on actual production: 1. How to truly prevent the occurrence of flue gas dew point corrosion during operation 2. The type and material of the waste heat recovery system (such as heat pipe type, etc.) 3. The technical modifications and effects of the waste heat recovery system (preferably with pictures)
1. The exhaust gas temperature should be controlled at no less than 150 degrees to prevent dew point corrosion. 2. The waste heat recovery system uses flow-circulating heating tubes.
Our unit’s measures to prevent dew point corrosion include:: 1. Replace the air preheater and use enamel material ； 2. Add a jumper to the cold path of the air preheater, that is, the air inlet and outlet, to adjust the air preheating amount. ； 3. Sampling and analyzing the dew point temperature of the heating furnace flue gas once a month.
It is recommended to use an oblique heat pipe flue gas exchanger. The material is 316. You can find out by checking it online. The kind that directly extracts the flue gas and exchanges it with cold air is not easy to use. The corrosion surface is too severe, so it is recommended not to use it. In operation, the oxygen content of the flue gas must be controlled, because if the oxygen content exceeds the standard, it means that the combustion air supply is seriously excessive, which will reduce the exhaust gas temperature. Also, the device should not be operated at ultra-low load for a long time, which will also cause insufficient exhaust temperature.
Air preheater with cast steel fin type.
It is recommended to use heat pipe waste heat recovery, which has good heat exchange effect. The medium heat transfer effect of the heat pipe is beyond the reach of ordinary body heat transfer devices.
1. Use water heat medium heat exchange technology, use hot water from the high-temperature economizer to exchange heat with deaerated water, and increase the temperature of the deaerated water entering the furnace, which generally needs to be greater than 135. 2. Adopt efficient soot blowing technology. 3. Reasonably allocate the selection of superheating section and preheating section. * * For example, ensure that the exhaust smoke temperature does not exceed 180°C. 4. Strengthen the management and insulation effect of on-site leakage and leakage.
This post was last edited by zhsju0315 on 2009-10-25 18:45 The exhaust temperature should be controlled at no less than 150 degrees to prevent dew point corrosion (for the flue gas recovery system). 1# Final Fantasy
For the waste heat recovery system of a piece of equipment, we cannot arbitrarily say which form of waste heat recovery is best. Depending on the load size of the furnace, consider placing it on the top of the furnace or on the ground. Based on the temperature of the convection exhaust smoke, judge whether a conventional heat pipe preheater is suitable. How clean is the flue gas? Can a plate preheater be used? In terms of layout, is it suitable to place it on the ground or on the convection roof? What is the direction of the flue gas and air? Are there any other How about adding a preheater to the heat source? How about using circulating hot air? What is the acceptable exhaust temperature of the unit (some units require an exhaust temperature of 160 to 180, which is fine, and some units require 120 to 130)? How long is the operation cycle, and how to consider the normal operation of the equipment when the waste heat recovery system fails? Many factors must be considered to determine what form of preheater to use. Nowadays, there are more used ones: heat pipe type, tube bundle type, plate type, heat medium type, and several combinations. Heat pipes are now also made into enamel tubes. Plate types are also made into cast iron plates. The form to be adopted must be comprehensively considered, which must be economical, safe, and flexible in operation.
Is enamel material easy to use? It is said that the technology is not very mature and the corrosion is serious!
Pay attention to control the sulfur content of fuel. If you use gas, turn on desulfurization. If using oil, control the sulfur content of the blend. Can further reduce the exhaust temperature!