脱硫泵浆体循环泵是继换热器和增压风机之后的脱硫系统中的大型设备。它通常采用离心式，直接从塔底提取浆液停止循环。它是脱硫过程中流量最大、操作条件最苛刻的泵。腐蚀和磨损常常招致其失效。其主要特性是：
在典型的石灰石（石灰）-石膏脱硫工艺中，塔底泥浆的pH值为5-6，参加脱硫剂后，pH值可达6-8.5（循环泵泥浆的pH值与脱硫剂的操作条件有关）。在塔上和脱硫剂参加点，Cl-可富集80000mg/L以上，在低pH值条件下会产生较强的Cl-活性。腐蚀性的
脱硫塔底泥浆中含有大量的固体颗粒，主要是粉煤灰和脱硫介质颗粒。粒径普通为0～400微米，90%以上为20～60微米，浓度为5%～28%（质量比）。这些固体颗粒具有很强的耐磨性。
在脱硫系统中，循环泵保送的浆液通常含有一定量的气体。事实上，离心循环泵保送的浆液是气-固-液多相流。固相对泵性能的影响是连续的、平均的，气体对泵性能的影响比固相的影响更复杂、更难以预测。
Slurry circulating pump of desulfurization pump is a large equipment in desulfurization system after heat exchanger and booster fan. It usually adopts centrifugal type to extract slurry directly from the tower bottom for circulation. It is the pump with the largest flow and the most severe operating conditions in the desulfurization process. Corrosion and wear often lead to its failure. Its main features are:
(1) Strong corrosivity
In the typical limestone (lime) - gypsum desulfurization process, the pH value of tower bottom mud is 5-6. After adding desulfurizer, the pH value can reach 6-8.5 (the pH value of circulating pump mud is related to the operating conditions of desulfurizer). On the tower and at the addition point of desulfurizer, Cl - can be enriched above 80000mg / L, and strong Cl - activity will be produced at low pH value. Corrosive
(2) Strong abrasion resistance
The slurry at the bottom of desulfurization tower contains a large number of solid particles, mainly fly ash and desulfurization medium particles. The particle size is generally 0 ~ 400 microns, more than 90% is 20 ~ 60 microns, and the concentration is 5% ~ 28% (mass ratio). These solid particles have strong wear resistance.
(3) Cavitation
In the desulfurization system, the slurry delivered by the circulating pump usually contains a certain amount of gas. In fact, the slurry transported by centrifugal circulating pump is gas-solid-liquid multiphase flow. The influence of solid phase on pump performance is continuous and uniform. The influence of gas on pump performance is more complex and difficult to predict than that of solid phase.
Field data: desulfurization pump type: 550dt-a75
Temperature: 70 ℃
PH value: 5.5
Mud solid content: 8 ~ 17%
Main ingredients: CaSO4 * 642; 2H2O
Material: cr30
The impeller and casing of desulfurization pump are subject to medium corrosion and solid corrosion during long-term operation. The service life of the impeller is about one year. At present, the pump casing of desulfurization pump manufacturer has not been replaced, but local corrosion and wear are serious.
