Analysis And Evaluation Of The Integration Characters In Superheated Steam Drying And Cleaning Combustion Of Coal

Due to the energy structure of the consumption is based on coal in China, and an imbalance exists between production and consumption, and coal is transported to the consumption area. The water content will increase the transportation cost. Drying of coal increases the calorific value(CV) and improves physical properties. The superheated steam drying of coal(SSDC) accords with clean, efficient, low-carbon and energy-saving demand.The coupling evaluation between the SSDC and the combustion is proposed based on the element analysis method(EAM) and the artificial neural networks. The SSDC is investigated using EAM, the first law of thermodynamics and the sensitivity analysis.The key technology for the SSDC is analyzed emphatically, and relevant technologies were also evaluated. For the SSDC, the system flowchart is presented and the numerical model is constructed based on the Aspen Plus. The change rule of physical properties of coal is studied with moisture variation. The energy consumption is compared with different drying systems. Combined with the SSDC, the energy consumption is optimized and the SSDC with four energy recovery modes is proposed. Through the EA, it is validated that the index of the CV of coal is mainly influenced by the C and H, and water conten is linear within CV. The coal consumption of power generation, the CV, the emission reduction of greenhouse gases, the air consumption and the total exhaust gas reflect the drying performance. Combined with the engineering applications, water conten in coal derives from the difference value of the C element and the equation of the coupling evaluation, the evaluation equation of the CV(Qcvc) and the power generation capacity of the combustion effect, is recommended. Finally, the typical applications of the SSDC are compared. The SSDC with exhaust heat recovery is proposed for the area of low-price, stable-supply in order to decrease the consumption and give full play of the SSDC. The main research content is as follows:(1) The composition of the element in coal is analyzed with the EA. The superheated steam is mainly evaluated by the weight losses method, according with the rate of change with the EA.(2) The water conten in coal decreases the increase of the pressure of the superheated steam(SS), and the secular change area accords with 7-12% water conten. The energy load is not evidently increased with the pressure of the SS and the key point is the system design and the selection of the heat transfer. Smaller energy consumption will realize the drying effect. The optimal pressure of the SS is about 0.3MPa, and the temperature of coal is increased with the pressure of the SS and will be steady eventually.(3) The sensitivity analysis validates that the CV of coal is mainly influenced by the C and H and that water conten is linear with CV, which can be used to evaluate the coupling effect. The sensitivity factor for the C element is 0.921109, whereas the sensitivity factor for the H element is 0.170678.(4) The coupling evaluation model is constructed. The CV is evaluated by the drying feature, and the power generation capacity is evaluated by the combustion. The Mar-online index in the drying process will influence the target value of the CV to control the drying and the target value of the power generation capacity to control both the drying and combustion. The Mar-online index in the combustion process will influence the target value of the power generation capacity to control the combustion and forecast the fuel information to control the drying and combustion. So Qcvc and Ppgc realize the coupling control of drying and combustion.(5)The SSDC is optimized. The SSDC with and without SS recovery can realize no gas emission, the condensate water recovery from SS, and the water recovery from coal. The water conten in coal reaches 8-12% to reduce 10-35% energy consumption reduction.