Optimization and application of the ultra-pressure press filtration system for dewatering of fine coal produced in Jiaozuo Mining Area

Jiaozuo Mining Area has a large output of fine coal which is difficult to sell for its high moisture and low calorific value. Since Zhongmacun mine′s coal preparation plant was selected by Jiaozuo Coal Industry (Group) Co. Ltd. as a pilot plant of the ultra-high-pressure press filtration system, altogether 14 such systems have now been introduced in Jiaozuo Mining Area. An introduction is made in the paper to the system′s technological process, main equipment selected and layout scheme. Based on analysis of the size composition and density of feed coal, as well as the feeding and pressing pressures, the optimum operating parameters of the system are determined. Analysis shows that the > 0.5 mm particles in feed should be reduced as much as possible because these particles can lead to plugging of feed hose or damage of filter cloth when they accumulate on the raised region of the filter plate; the feeding time decreases with the increase of feed density and feeding pressure, and the optimum values of the two parameters should be set at 550 g/L and 1.1 MPa, respectively; and the moisture of the product of the system decreases with increase of pressing pressure, and the optimal pressing pressure needs to be adjusted by each mine to suit the specific requirement. As indicated by results of field application of the filtration system after optimization of influencing factors, the system can maintain stable operation with a high automation and intelligent level; the dewatering efficiency is effectively improved due to sharp reduction of filtration cycle time to about 70 minutes; the dewatered product is effectively upgraded as its moisture is lowered to around 14.5% with its calorific value increased by approximately 2.84 MJ/kg; and the filtered slime product can be directly sold or blended into power coal after being crushed. The use of the system can lead to an additional economic revenue of 77.4082 million yuan, total recovery of coal slime and noticeably favorable social and economic benefits.