Sublimated sulfur severely clogs the equipment

Are you sure it’s arsenic sulfide? Please specify the color and state of the blocking substance. Generally, sublimed sulfur comes in 4 colors: in the high-temperature sections of the flue ducts, it forms orange-red sulfides after combustion; these can be seen during maintenance. The purification venturi tubes and packing towers are white in color, while the electrostatic precipitators are green-brown. The drying cycle tanks contain light green floating particles as well as white floating particles

This post was last edited and replied to by 303740873 on 2011-7-14 08:55. Reply to 2# gaolei0993: It’s slightly yellow; it’s present all over the bottom and side walls inside the Venturi tube

This post was last edited by 303740873 on 2011-7-14 08:54. What causes the sublimation of sulfur? What wasn’t controlled properly?

Incomplete combustion, that is, insufficient air supply, leads to the formation of sublimed sulfur, a phenomenon that often occurs at the beginning of operation.

Our company’s new system also experienced severe sulfur sublimation blockages at the beginning of operation. After analysis, measures taken included 1) reducing the amount of ore fed in and adjusting the dilution valve to control the gas concentration； 2. Slightly open the manhole at the boiler outlet to supply oxygen, allowing the sublimated sulfur to burn a second time in the cyclone and electrostatic precipitator.

The best – and also the most straightforward – method is to closely monitor the color of the slag while driving. It’s ideal to keep the slag red; brown is acceptable as well. It’s necessary to assess control capabilities, conduct frequent analyses of gas composition, and make adjustments accordingly. Having red slag ensures high conversion efficiency in the initial stages of operation of the converter, prevents blockage of the demister in the drying tower, which could lead to forced shutdowns, and also helps to avoid excessive emissions

Reply to 7# gaolei0993: The conversion rate is decent, but the shutdown failures caused by sublimated sulfur are quite troublesome; the amount of cleaning required is also significant. This issue also occurs in electric mist eliminators. Is there any better way to control oxygen content?

It is known that controlling the slightly dark color of slag and ash is possible, but it is difficult to do so manually; it is better to use an oxygen meter to control the oxygen level. Additionally, it is important to maintain a stable and uniform sulfur content in the ore fed into the furnace, avoiding large fluctuations in the amount of material added.

Reply to 8# 303740873: There are ways to do this through system collaboration: 1. Improve the process control capabilities in the roasting section. Usually, experienced operators can determine the gas concentration based on the temperatures of the upper, middle, and lower layers as well as the temperature at the exit of the electrostatic precipitator; this relies on their operational experience, along with feedback from the color of the slag discharged. Of course, it would be ideal if the oxygen meter also functions properly. 2. Install a sight glass in the packed tower (foam tower), along with a camera, to monitor the gas concentration. With an experienced operator, this approach can ensure 100% control over the amount of sublimed sulfur and the gas concentration. 3. In the conversion section, the gas concentration can be determined based on the temperature at the exit of stage 5. 4. In the dry absorption section, the gas concentration can be assessed by observing the normal water addition volume during the first absorption step, as well as the liquid level in the drying cycle tank; a whitish color of the acid is an early sign of sublimed sulfur

The atmosphere in the firing section was not properly controlled. It is mainly caused by insufficient oxygen supply, but too much oxygen cannot be provided either; a low-oxygen atmosphere should be maintained.