Smoke desulfurizing process by circulation fluid state dry method of layered feed back

Abstract

The present invention relates to external grain re-circulating technology in large circular fluidizing dry fume desulfurizing system. The desulfurizing process includes preparing desulfurizing agent, desulfurizing reaction inside the desulfurizing reaction tower and external desulfurizing agent grain separation and re-circulation. In the external grain re-circulation, the returned material is two-stage separated and re-circulated, the grains separated by the first stage and the second stage desulfurizing agent grain separator are fed to the fluidizing region in the lower part of the desulfurizing reaction tower separately through different re-circulation inlets, resulting in raised desulfurizing agent grain utilization and desulfurizing reaction efficiency. Compared with available technology, the present invention has much higher fume dedusting efficiency, high desulfurizing efficiency up to 92 % at Ca / S of 1.1-1.3, less adhesion and blocking in the lower desulfurizing tower part and lowered load of the desulfurizing agent grain separator.

Description

technical field [0001] The invention belongs to the technical field of flue gas desulfurization, relates to dry desulfurization of flue gas exhausted by various combustion equipment, and specifically refers to a circulating fluidized dry flue gas desulfurization method using layered recycling. Background technique [0002] The control of sulfur dioxide gas pollution in the flue gas exhausted by combustion equipment has always been the focus of environmental protection in most countries in the world. It is imperative. For the treatment of sulfur dioxide in flue gas, foreign countries usually use wet lime gypsum method (W-FGD) to desulfurize. A series of problems such as large size, complex structure, and the need to retreat water. Therefore, dry or semi-dry flue gas desulfurization technology has become the focus of research and development at home and abroad. For dry or semi-dry flue gas desulfurization technology, the main factors affecting desulf...

AI Technical Summary

Problems solved by technology

However, the dry flue gas desulfurization technology using the above-mentioned single return method still has the following defects: First, due to the use of a single dust collector and return port, the particle size of the recirculated particles varies in a large range, resulting in the desulfurization tower. The collision between solid particles and the contact between solid particles and flue gas are insufficient, and the mixing of flue gas and desulfurizer particles is weakened, which in turn affects the utilization rate and desulfurization efficiency of desulfurizer

Secondly, because there are many desulfurizer particles with smaller particle sizes on the bottom and bottom slope of the desulfurization tower, and the small particle size desulfurizer particles have strong cohesiveness, which is easy to form a bond at the bottom of the desulfurization tower and the bottom slope. The phenomenon of clogging

In addition, when the dry flue gas desulfurization unit is large-scaled, the amount of recycled materials will increase a lot. Using a single recycling method will greatly increase the burden on the dust removal system and the recycling pipeline, which will not only affect the dust removal effect of the dust removal system, but also make the dust It is difficult to meet the emission standards, and it will affect the normal operation of the entire unit due to the decrease in the safety of the dust removal system and the return pipeline

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