Improve the quality of tar ammonia under the existing process
l increase tar production by 0.3-2%
l Improve wastewater (COD) quality to meet environmental protection requirements
l reduces the tar moisture by about 50% (middle tank and storage tank)
l Purify gas, which is beneficial to the deep processing of gas
l Significantly reduce the deposition of ammonia water heat exchangers, ammonia washing towers and ammonia distillation towers and the corresponding cleaning frequency
l Significantly reduce the tar deposition of the primary cooler, increase the heat exchange rate of the primary cooler, and reduce the corresponding cleaning frequency
l Reduce the 75% effect of the gas collection pipe spray blockage, and reduce the corresponding nozzle cleaning frequency and intensity
l Reduce the gas outlet temperature of the gas collector by about 0.5-2°C.
Application of demulsifier in separation of ammonia tar
ammonia separator is mainly responsible for the separation of tar ammonia mixture after coke oven gas cooling. Due to the influence of residence time, coal powder and emulsion in coke oven gas, the interface of ammonia separator also fluctuates, which causes the tar water content to rise sharply in severe cases. At the same time, a large amount of tar is entrained in the circulating ammonia water, which affects the normal production of coke oven and tar device and affects the subsequent treatment of remaining ammonia water.
At present, coking plants mainly rely on adjusting temperature, increasing residence time and centrifugal separation to improve tar quality and improve the separation effect of ammonia tar. Domestic use of chemical agents to improve the effect of ammonia tar separation. Considering the possible increase of coal powder entrainment and the difficulty of ammonia tar separation caused by the use of a coal moisture control device in a coking plant, an exploratory study on the use of chemical demulsifiers in the ammonia tar separation system was carried out to provide technical reserves for coal moisture control.
the chemical code selected for this test is XK-0608, and its main physical and chemical properties
Its working principle is: the demulsifier is XK-0608 an oil-soluble demulsification and viscosity reducer. After the agent is added to the system, most of it is combined with the tar in the ammonia water. In the separator, it can strengthen the separation speed of the tar and ammonia water. And the separation effect, and through the effects of demulsification, dispersion, and viscosity reduction, the ammonia tar emulsion layer is thinned, and the purpose of improving the separation efficiency of the ammonia tar in the separator is achieved, thereby reducing the content of suspended solids entrained in ammonia water, appropriately reducing the surface tension of tar, accelerating the separation of tar and tar residue to obtain tar with lower moisture content and residue, and at the same time greatly reducing the suspended solids entrained into ammonia water And oil content, improve the quality of circulating ammonia water, and strengthen the effect of residual ammonia treatment.
the laboratory static simulation research is mainly to simulate the field working conditions (internal temperature of ammonia separator: 75~80 ℃), to carry out a small laboratory test of XK-0608 chemicals, to determine the theoretical concentration, and to evaluate the influence of the chemicals on tar quality after use.
through static test research under simulated working conditions, it is determined that the theoretical optimal concentration of the agent is 100 ~ 400ppm. At the same time, the tar quality was analyzed under the condition of adding chemicals, and the change was not significant, as shown in Table 2.
table 2 analysis results of tar performance before and after adding chemicals
density (15 ℃)
tar slag content
Initial distillation point
170~230 ℃ fraction
230~300 ℃ fraction
300~350 ℃ fraction
>350 ℃ fraction
2.1 test process
this test was carried out in the ammonia system of the first phase of a coking plant. The reagent in the high-level tank is continuously added to the ammonia water intermediate tank through a quantitative pump. Since the XK-0608 is an oil-soluble product, it returns to the coke oven with circulating ammonia water and enters the ammonia water separator after cooling the riser gas. In the ammonia separator, the XK-0608 demulsifier is combined with tar to improve the separation effect of tar and ammonia through demulsification, dispersion and viscosity reduction, and the XK-0609 agent after reaction enters the tar system.
1-ammonia separator; 2-tar separator; 3-pharmaceutical high-level tank;
4-circulating ammonia water intermediate tank; 5-pharmacy pump; 6-circulating ammonia water pump
analysis of 2.2 test results
Langfang xingke special chemical XK-0608 was used in this industrial test. metering pump was used to continuously add the intermediate tank of ammonia water in the first phase. the dosage concentration of the drug was controlled at 100 ~ 400ppm. Considering the possible influence of the tar stripping originally accumulated inside the pipeline on the ammonia nozzle on the coke oven at the initial stage of the test, the method of gradually increasing the concentration of the reagent was adopted, and the initial concentration of the test was controlled at 50 ~ 100ppm. The industrial test lasted for about 3 months. During the test, the quality differences of ammonia and tar before and after the addition of the drug and under different drug concentrations were mainly tracked.
(1) comparison before and after drug addition. After the agent was added, the ammonia nozzle on the coke oven did not become more clogged, and with the test, the nozzle clogging was improved to a certain extent. Before and after the addition of the agent, the effect on the separation performance of ammonia and tar is specifically manifested in the changes of tar moisture, viscosity, tar residue and suspended ammonia.
table 3 comparison of ammonia and tar indexes before and after the test
Ammonia water suspension
(2) Comparison of different drug concentrations. During the experiment, the changes of tar moisture and viscosity under different drug concentrations were tracked. Below 100ppm, with the increase of the concentration of the agent, the tar moisture and viscosity improved significantly, but after the concentration exceeded 100ppm, the tar moisture and viscosity changed little.
(3) Influence on the quality of circulating ammonia in coke ovens. The change of ammonia water quality is tracked as an auxiliary index of the effect of the agent on the performance of the separator. According to the test results, the suspended substance content in circulating ammonia water decreased by about 31%, and the entrainment of ammonia tar and viscosity of ammonia water were improved to a certain extent. More importantly, the mass fluctuation of tar and ammonia water is greatly reduced, the standard deviation of tar moisture is reduced by 44%, and the standard deviation of suspended ammonia water is reduced by 49%.
by comparing the first-stage circulating ammonia water added with the drug with the second-stage circulating ammonia water without the drug, the results of laboratory filtration test of 200mL circulating ammonia water using standard 0.45um filter paper show that the filtration time of the first-stage is 2 min55 s and the second-stage is 30 min47 s, indicating that the fluidity of circulating ammonia water has been greatly improved. The movement is greatly reduced, the standard deviation of tar moisture is reduced by 44%, and the standard deviation of ammonia suspended solids is reduced by 49%.
by comparing the first-stage circulating ammonia water added with the drug with the second-stage circulating ammonia water without the drug, the results of laboratory filtration test of 200mL circulating ammonia water using standard 0.45um filter paper show that the filtration time of the first-stage is 2 min55 s and the second-stage is 30 min47 s, indicating that the fluidity of circulating ammonia water has been greatly improved.
(1) it is feasible to add chemical demulsifier assisted tar ammonia separation to ammonia separation system and has no significant effect on tar composition.
(2) adding demulsifier/binder can greatly improve the separation performance of ammonia water and tar, which is beneficial to stabilize the quality of tar and ammonia water, and can be used as a supplementary technology for separation of ammonia water tar.