cement production;cement, ordinary portland cement, 42.5MPa;new dry process, low-temperature waste heat power generation technology, 2000 t/d;fly ash
Laboratory data. New dry process low temperature waste heat power generation.The cement is produced by burning carbide slag generated by the acetylene industry in Heilongjiang. The new dry production line for low-temperature waste heat power generation uses the exhaust gas waste heat from the cooler at the kiln head and the preheater at the kiln tail, which is about 350°C, as the heating energy source. The low-pressure backpressure steam turbine is used for low-temperature waste heat power generation. An AQC waste heat boiler (vertical structure) is installed between the kiln head cooler and the waste gas fan, with a settling chamber before the AQC boiler. An SP waste heat boiler is installed between the kiln tail rotary kiln outlet and the high-temperature fan.The AQC boiler adopts the middle section air extraction with recycled waste gas method, and the original waste gas extraction port is changed into two extraction ports, with one high-temperature extraction port located in the front and one low-temperature extraction port located in the rear. The high-temperature hot air from the front extraction port is recovered after some fly ash is collected in the settling chamber and sent to the AQC boiler, while the low-temperature extraction port is mixed with the AQC boiler outlet air and processed by the original cement production line dust removal system. The waste gas at the kiln tail is cooled and heated by the SP boiler to around 230°C, and a part of it is sent to the raw material mill of the original system by the high-temperature fan, while the other part is humidified in the humidification tower before being sent to the tail gas dust collector. If the power generation system stops operating, the waste gas enters the high-temperature fan through the waste gas pipeline of the original system to ensure the stable operation of the cement production line.Through heat exchange, the boiler produces superheated steam, which is sent to the mixed steam cylinder for mixing and then enters the steam turbine for power generation through the superheated steam pipeline. The low-pressure steam from the steam turbine enters the condenser, where the steam condenses into water, which flows into the hot water well and is then pumped into the vacuum deaerator by a water pump. The water is then pumped into the AQC boiler for circulation by the feedwater pump. When utilizing this dataset for environmental impact assessments and life cycle analyses, LCA practitioners should closely consider the specific operating conditions detailed, such as temperatures and energy outputs. Attention should be paid to the implications of energy- and resource-efficiency improvements, integration of waste materials (fly ash and carbide slag), and emission reductions due to the waste heat recovery system. It's important to note that clay resource consumption and the environmental impact of iron powder correction materials are excluded from this data. Emission data for NOx, SO2, CO2, and dust at the output end should be taken into account.
This section selects the above process and uses calcium carbide slag produced by the Heilongjiang Yikuai chemical industry to burn cement to improve the environmental coordination of the Heilongjiang cement industry and promote the sustainable development of the cement industry. The process flow of pre-drying, dry grinding and dry burning is shown in Figure 5-1. Figure 5-4 shows the process flow of low-temperature waste heat power generation in the new dry process production line. This process uses about 350% flue gas waste heat discharged from the kiln head clinker cooler and kiln tail preheater as heating energy, and generates low-temperature waste heat power generation through a low-pressure steam turbine. An AQC waste heat boiler (vertical structure) is arranged between the kiln head cooler and the residual air fan, and a descending chamber is arranged in front of the AOC boiler; an SP waste heat boiler is installed between the outlet of the tail first-stage rotor and the high-temperature fan.The AQC boiler adopts the middle exhaust with residual air recirculation method. The original residual air exhaust outlet is changed to two exhaust outlets. One of the new exhaust outlets is moved to the front and the other is moved to the rear. The hot air from the front high-temperature exhaust outlet recovers part of the fly ash through the settling chamber. It is sent to the AOC boiler. The moved low-temperature exhaust air is mixed with the AOC boiler outlet air and then processed by the dust removal system of the original cement production line. The dense tail exhaust gas absorbs heat and is cooled to about 230C by the SP boiler. A part of the high temperature fan is sent to the raw meal mill of the original system, and the other part is humidified by the humidification tower and then sent to the tail dust collector. If the power generation system is disabled, the exhaust gas The exhaust gas pipe of the original system enters the high-temperature fan to ensure stable operation of the cement production line.Through heat energy exchange, the boiler generates superheated steam, which is sent to the separate cylinders for mixing, and then enters the steam turbine through the superheated steam pipe to generate electricity. The spent steam from the steam turbine enters the condenser. The spent steam condenses into water in the condenser and flows into the hot water well. It is then sent to the vacuum deaerator by the water pump, and then pumped into the AQC boiler through the feed water pump for recycling.