A GAS HEATING SYSTEM USED IN BOILING GRANULATOR, COATER AND SPRAY DRYER
Abstract: Traditional equipment such as boiling granulator, coating machine and spray dryer often use steam as a heat source in large-scale production. Now we introduce a new technology: the use of gas heating system to solve the problem of energy in the energy transfer of heat source in boiling granulator (including vertical and horizontal), coating machine and spray dryer. The problem of loss is achieved, the effect of energy saving and consumption reduction is achieved, and the production cost is reduced, thereby producing better economic benefits.
The current boiling granulator (including vertical and horizontal), coating machine, spray dryer and other equipment, the hot air required in the process of heating the material is the heat exchange of the normal temperature air through steam, and the steam It is produced by burning natural gas in a boiler to vaporize water. In this process, the energy transfer of “natural gas – water (water vapor) – air – material” is followed in turn, and there is inevitably loss in the process of energy conversion, and according to the law of conservation of energy, the material is finally obtained from the combustion of natural gas. The energy conversion efficiency is relatively low. Due to the material characteristics, production process and equipment requirements, it is impossible to directly burn natural gas to heat the material. Therefore, a gas-fired air inlet cabinet is used to transfer energy through the simplest route of “natural gas-air-material” to effectively improve the heat exchange efficiency. Save energy costs and improve economic efficiency.
1 Principle of gas heating system
To understand the principle of the gas-fired boiling granulator, you should first understand the working principle of the gas heating system applied in this technology, that is, the new type of hot blast stove.
The structure of the traditional hot air device is mostly a straight-through mechanism, that is, a radiant sleeve is used at the front end, and a tubular heat exchange component is used at the end. As shown in Figure 1, the fuel is burned in the combustion cylinder, and the flue gas after combustion must first pass through a radiant section (or a mixing chamber that directly mixes part of the cold air) to reduce the temperature of the flue gas to 400-500 °C, and then enter the The heat exchanger in the latter stage (the heat exchanger can be in any form such as tube, heat pipe, plate, etc.), as a result, a large amount of high-level heat energy is wasted, and the upper temperature limit of the heated clean air is also limited. The main disadvantages of traditional devices are that the equipment is bulky and occupies a large area, consumes a large amount of steel itself, and has low heat transfer efficiency.
The new type of hot blast furnace is composed of a combustion furnace and high-efficiency plate heat exchange components. As shown in Figure 2, the integrated design of the combustion furnace body and the heat transfer in the radiation section of the device, and the furnace chamber designed with corrugated tube is directly used as the body of the radiation heat transfer, which not only expands the heat transfer area, but also strengthens the heat transfer intensity of the radiation section. It can effectively solve the problem of weld cracking caused by the thermal stress of the metal under high temperature conditions. Plate heat exchange components are used in the low temperature section, stainless steel is used for the medium overflow part, which has good temperature resistance and corrosion resistance. , can effectively resist the low temperature dew point corrosion of carbonic acid of natural gas and diesel flue gas, the whole device has compact structure, less consumables, small footprint and high heat transfer efficiency.
Principle of gas-fired boiling granulator
As shown in Figure 3, after the inlet air is treated by the primary filter and the medium-efficiency filter, it passes through the surface cooling and dehumidification sections, and then enters the gas heating system. The gas heating system heats the inlet air to reach the temperature required by the process. It enters the equipment through the air inlet duct, and after heating the material, it is discharged to the atmosphere through the exhaust duct and a series of dust removal and noise reduction treatments to meet the environmental protection requirements.