Bottom structure of medium-speed coal mill

Abstract

The invention discloses a bottom structure of a medium-speed coal mill. The bottom structure is shaped like a hollow cylinder; an inner cavity at the bottom of the medium-speed coal mill is a bottom air chamber; an air ring is arranged above the bottom air chamber; an arc air inlet is formed in one side wall of the bottom air chamber; the air inlet is externally connected with an air feeding groove plate with an air feeding channel; and two fan-shaped flow guide baffles which are spaced from each other are uprightly arranged inside the bottom air chamber along the circumferential direction of the bottom air chamber, are arranged on the same concentric circle taking the center of the bottom air chamber as a circle center and are respectively adjacent to joints of two side ends of the air feeding groove plate and the air inlet. The two fan-shaped flow guide baffles are symmetrically distributed relative to the middle bisectrix of the air inlet. According to the bottom structure, the distribution of a flowing field in the coal mill is optimized, and a phenomenon that the flowing field is not distributed uniformly because of air feeding from one side is relieved and even eliminated; pebble coal is rationally discharged; and the coal mill can normally mill the coal.

Description

technical field [0001] The invention relates to a medium-speed coal pulverizer, in particular to a bottom structure of the medium-speed coal pulverizer. Background technique [0002] With the increasing scale of thermal power plants and the gradual improvement of energy conservation awareness in recent years, more and more positive pressure direct-blowing pulverizing systems are equipped in my country's active and newly-built units above 300MW, which have the advantages of rapid start-up. , flexible adjustment, small resistance, small metal wear per unit of coal grinding, compact structure, small footprint, low unit power consumption, small explosion risk and low noise. [0003] However, due to the congenital deficiencies in the design of the structure itself and the variability of the actual coal types used in power plants, the medium-speed coal mills actually put into operation in China generally suffer from insufficient output, abnormal discharge of pebble coal, rapid wear...

AI Technical Summary

Problems solved by technology

However, this method can only be carried out by relying on the operating experience of the technicians in the power plant or the design experience of the coal mill design manufacturer. As for which wind ring blades are blocked, there is no accurate quantitative basis, so the transformation results are often unsatisfactory.

Even if it is the air ring blade that has a big problem that is blocked, it is not enough to obtain an ideal uniform flow field distribution inside the medium-speed coal mill, and the effect of this transformation is very limited

Moreover, after blocking part of the air ring, due to the reduction of the flow area at the air ring, the overall pressure drop of the medium-speed coal mill will rise sharply, which will lead to a substantial increase in energy consumption, and may cause insufficient output of the coal mill and unit change. Major problems such as insufficient load rate

Therefore, the current transformation of the existing technology is firstly based on qualitative empirical analysis without quantitative data support, and secondly, the effect of this transformation itself is not obvious, which makes this type of coal mill run in an unreasonable way for a long time state, bringing economic and even security issues

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