CN102430551A

CN102430551A - Descaling method for slurry conveyance pipeline of monoammonium phosphate drying tower by steam blowing

Info

Publication number: CN102430551A
Application number: CN2011103854147A
Authority: CN
Inventors: 金岭; 许进冲; 张爱笑
Original assignee: Anhui Liuguo Chemical Industry Co Ltd
Current assignee: Anhui Liuguo Chemical Industry Co Ltd
Priority date: 2011-11-28
Filing date: 2011-11-28
Publication date: 2012-05-02
Anticipated expiration: 2031-11-28
Also published as: CN102430551B

Abstract

The invention relates to a descaling method for a slurry conveyance pipeline of a monoammonium phosphate drying tower by steam blowing, comprising the following step of continuously feeding steam into the slurry conveyance pipeline, wherein the steam is fed in the slurry conveyance pipeline through the outlet end of the slurry conveyance pipeline, and fed out through the inlet end of the slurry conveyance pipeline. According to the descaling method provided by the invention, each blowing descaling time is shortened to more than a half, the steam consumption amount is largely reduced, the steam use amount can be reduced by 2200 m3 each year, and the production efficiency is further improved; and the slurry carried in the blowing tail gas can be recycled, so that the nutrient utilization can be improved, and the environmental pollution is decreased.

Description

The steam blowing descaling method of MAP drying tower slip conveyance conduit

Technical field

The present invention relates to a kind of steam blowing descaling method of MAP drying tower slip conveyance conduit.

Background technology

Adopt slurry concentrated process to produce MAP, the MAP slip after need ammonification neutralization, two-effect evaporation being concentrated is delivered to pipeline and carries out drying and dehydrating in the spray drying tower.Because the MAP pulp density after two effects concentrate is up to 1.5g/ml, viscosity is bigger, and slip is easy scale formation in conveyance conduit, blocking pipe, essential pipe blow-through regularly.Usually aborning; Adopt about 150 ℃ of temperature, the water vapour about pressure 0.2Mpa is imported in the pipeline by entrance, and ventilation purges continuously; Water vapour will soften attached to the slip on the tube wall, the dilution back is taken pipeline out of with air-flow, carry the tail gas of slip and discharged by emptying pipe.Because each scale removal time is longer; Each about 7 minutes of scale removal time ability is accomplished clean-up task, and is bigger for the required water vapour amount of the each scale removal of this purging mode, is example with the production line of producing the 120kt MAP per year; Steam consumption quantity reached 50t in 1 year, needed to consume great amount of heat energy.

Summary of the invention

The steam blowing descaling method that the purpose of this invention is to provide a kind of MAP drying tower slip conveyance conduit can reduce the consumption of the used water vapour of scale removal, with energy savings.

The present invention is achieved in that the port of export of water vapour by the slip conveyance conduit is imported in the slip conveyance conduit continuously, and derived by the entrance point of slip conveyance conduit.

The inventor finds in the long-term production practice; Water vapour purges the big main cause of scale removal consumption quantity of steam by the slip throughput direction to pipeline: the layer of scale thickness on the inner-walls of duct has directionality; Be that entrance point is thin, the port of export is thick, and the entrance point layer of scale is densification and smooth surface not only.Its origin cause of formation has two, and first pipe head discharge pressure is big; It two is that the slip conveyance conduit has bigger difference in height, and the port of export exceeds more than the 20m than entrance point, and slip has aggravated the directionality tendency of this fouling under the effect of deadweight.When getting into pipeline along entrance point, steam carries out forward when purging; Smooth and the fine and close layer of scale of entrance point is bigger to the temperature and the pressure consumption of steam, blows out pipeline and also causes its temperature and pressure consumption and the slip after softening, diluting needs steam upwards to overcome its gravity.And the present invention adopts the reverse blowing method of steam, and the soft layer of scale in pipeline upper end contacts with high temperature and high pressure steam earlier, degrades downwards layer by layer; And with the pulp flow under the steam flush when the lower end of duct inwall; The fouling top layer is washed away, destroyed its surface, so that degrade; And the process that slip is discharged not only less consumes steam energy, and the slip deadweight also helps downward accelerated motion, increases the trend of destroying lower end of duct fouling top layer; Make wet-hot steam be easy to soak into its inside; Quicken its softening becoming flexible, thereby can shorten the time of each purging scale removal, reduce steam consumption; Can also prolong simultaneously the driving time of drying device, enhance productivity.

A preferred version of the present invention is: purge tail gas and refluxed through the emptying of slip feeder by evacuated tube.Purge tail gas and directly do not drain into the external world, the slip that carries in the tail gas can access recovery, can improve plant recovery of nutrient, reduces environmental pollution.

Can know by technique scheme; Though the present invention just changes the steam blowing direction; But play unexpected effect, the time that each scale removal imports water vapour can be shortened to by original 7 minutes about 3 minutes, and the purging scale removal time shortens over half; Not only reduce steam consumption greatly, can reduce steam use amount 2200m every year ³, can also enhance productivity; Purge the slip that carries in the tail gas and can access recovery, can improve plant recovery of nutrient, reduce environmental pollution.

Description of drawings

Fig. 1 is a process principle figure of the present invention.

The specific embodiment

As shown in Figure 1, imitate concentrated MAP afterwards from two and get into by slip conveyance conduit 3 bottom inlet ends through valve 2 by high pressure shurry pump 1, the port of export is sent into the dehydration of drying tower 5 inner dryings through valve 4 through top again.

When needing scale removal; Valve-off 4; With temperature about 150 ℃, the water vapour of the about 0.20MPa of pressure imports in the slip conveyance conduit 3 by slip conveyance conduit 3 ports of export through valve 7 by pipeline 6 continuously, and derived through valve 2 by the entrance point of slip conveyance conduit 3, purge tail gas and be back in the slip feeder 9 by evacuated tube 8; The slip that purging tail gas carries is deposited on slip feeder 9, purges the tail gas emptying.When no slip flows out in purging tail gas, stop air feed, purge and finish.

Production line to produce the 120kt MAP per year is an example, and each purge time only needs about 3 minutes, and the slip that carries in the tail gas is deposited on the slip feeder, can access recovery, reduces environmental pollution simultaneously.

Claims

1. the steam blowing descaling method of MAP drying tower slip conveyance conduit; Water vapour is fed in the slip conveyance conduit (3) continuously; It is characterized in that: said water vapour is imported in the slip conveyance conduit (3) by the port of export of slip conveyance conduit (3), and is derived by the entrance point of slip conveyance conduit (3).

2. the steam blowing descaling method of MAP drying tower slip conveyance conduit according to claim 1 is characterized in that: purge tail gas and refluxed through slip feeder (9) emptying by evacuated tube (8).