Shaft seal structure of centrifugal coal slurry pump

Abstract

The invention relates to a shaft seal of a centrifugal coal slurry pump of a coal water slurry gasification device. For overcoming the defect that a mechanical seal of a centrifugal low-pressure coal slurry pump in the prior art is not long in service life and cannot completely prevent external flushing water from flowing into the pump, three to five spacing rings are added on a back blade and blades of an auxiliary impeller of the shaft seal to weaken harmful radial flows in a flowing channel and increase a blocking lift of high-viscosity coal slurry. An external area of an auxiliary impeller cavity is a large-specific-gravity coal slurry ring, an internal area of the auxiliary impeller cavity is a small-specific-gravity oil ring, and the interface of the two areas is obvious and stable. PLAN23 single-end-face mechanical seal and an improve liquid seal tank are adopted to enable the auxiliary impeller cavity, a mechanical seal cavity and the liquid seal tank to be communicated, it can be monitored that the coal slurry is away from the mechanical seal in a central control room and a field, long service life is ensured, and external flushing water is not needed completely during normal operation. The shaft seal is suitable for the centrifugal coal slurry pump of which the conveying solid content is 58-61 wt% and the viscosity is 700-3000 mPa.s and is also suitable for other high-viscosity centrifugal pumps with high conveying solid content.

Description

technical field [0001] The invention relates to a shaft seal structure of a centrifugal coal slurry pump with a solid content of 58-61wt% and a viscosity of 700-3000mPa.s in a coal-water slurry pressurized gasification device, in particular to a shaft seal of a coal mill discharge trough pump It is also suitable for the shaft seal structure of centrifugal pumps for conveying high solid content and high viscosity media in other industrial devices. Background technique [0002] In the past ten years, due to the continuous rise of oil prices and the resource structure of my country's lean oil, little gas, and rich coal, it has been decided that "replacing oil to coal and gas to coal" is a major national strategic policy. Therefore, coal is used as raw material for production. Modern coal chemical industries such as methanol, olefins (MTO), natural gas and coal-to-liquids have developed rapidly. Coal gasification is the leader of modern coal chemical industry. Coal water slurry ...

AI Technical Summary

Problems solved by technology

But in actual use, in order to prolong the life of the mechanical seal, the amount of flushing water entering the pump often exceeds 500ml, which is not good for the coal gasification process, and increases the load and oxygen consumption of the coal gasifier, such as flushing water pressure and seal oil pressure. Control error, there is a risk of water entering the double seal, shortening the life of the rolling bearing in the middle of the double seal

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