Why is ammonia water used for cooling coke oven gas?

Because ammonia absorbs a large amount of heat when it is converted to ammonia gas, this lowers the temperature of the coal gas

It seems to be just one of the reasons.

Ammonia is also alkaline, and it can react with acidic gases such as acid tar vapor present in raw gas, thereby reducing corrosion of the pipelines. Additionally, ammonia has a lubricating effect that helps to lower the resistance in the raw gas flow.

I think the desulfurization effect is the main reason. If we want to lower the temperature of the gas, it would be better to use water; ammonia has a low specific heat, so it absorbs less heat during vaporization.

4th floor: Is it correct that “in addition, ammonia has a lubricating effect and can reduce the resistance of raw gas”? It should facilitate the flow of tar. This post was last edited by Keke on 2009-3-25 15:33.]

The reason for using ammonia water for spraying is: 1. To lower the temperature of the gas (which is the main purpose), as the conversion of ammonia water into ammonia gas is an endothermic process that can reduce the temperature of the gas； 2. Since ammonia is alkaline, it can react with acidic gases such as acid tar present in raw gas, thereby reducing the pressure on subsequent gas purification equipment (such as primary coolers, electrostatic tar collectors, etc.). As for whether it has a desulfurization effect, I’m not quite sure. I would appreciate some guidance from those who are more experienced.

Cooling with ammonia does not increase the amount of wastewater discharged

There are 3 reasons: 1 is that the latent heat of vaporization of ammonia is greater than that of water, so it absorbs more heat than water； 2 is ammonia water, which is alkaline; it can neutralize coal tar acid and protect coal gas pipelines ； Ammonia water, with a number of 3, also has lubricating properties, which facilitate the flow of coal tar. It helps to prevent the accumulation of coal tar residue – formed from a mixture of coal powder, coke particles, and coal tar during the cooling process of gas – from blocking the gas pipes. (Source: Textbook on the Recovery and Processing of Coking Chemical Products)

The latent heat of vaporization of ammonia is only about 1370 kJ/kg, which is approximately 60% of that of water at the same temperature.

When cooled with clean water, it will turn into ammonia after a few cycles; therefore, clean water must be added to the circulation tank regularly to reduce the ammonia concentration.

It seems to have no desulfurization effect; its main functions are cooling and neutralizing tar acids. When hot ammonia water evaporates, it releases a large amount of latent heat, which means more heat is absorbed, resulting in an excellent cooling effect

【1】Firstly, ammonia is a by-product of the coking production process； 【2】Secondly, ammonia water has a high heat of vaporization, which can absorb the heat from the gas and thereby lower its temperature. That’s what the textbook says, hehe.

Spraying cooled gas with hot ammonia water facilitates the evaporation of ammonia water, thereby enhancing the cooling effect on the gas. At the same time, it does not cause the viscosity of the cooled tar to increase, thereby preventing blockages. Furthermore, ammonia water also serves to neutralize taric acid and protect the pipes, and it has lubricating properties that facilitate the flow of tar.

1. Spray cooled gas with ammonia; as ammonia evaporates, it absorbs a large amount of latent heat, resulting in a better cooling effect than water； 2. Ammonia water is alkaline and can neutralize a portion of the tar acids in coal tar, thereby reducing corrosion of coal gas pipelines ； 3. Ammonia water has lubricating properties, which facilitate the flow of coal tar; it also prevents the accumulation of coal tar residue formed from a mixture of coal powder, coke particles, and coal tar during the cooling process of gas, thereby avoiding blockages in the gas pipes ； 4. Reusing ammonia water can reduce the amount of residual ammonia, thereby decreasing the energy consumption required to treat it. Furthermore, since ammonia water contains ammonia, it no longer absorbs or absorbs very little ammonia from the gas, which facilitates the absorption of ammonia in the ammonium sulfate production process and improves yield ； This post was last edited by lhq6388 on 2009-4-1 09:35.]

Taking advantage of the high volatility of ammonia, its extensive evaporation absorbs a large amount of heat, whereas water can absorb only a limited amount of heat through evaporation. This is their difference. Additionally, ammonia is produced during the carbonization of coal, and ammonia water can be reused, so there is no need to purchase it separately.

Let me explain the reasons why cold water should not be used for cooling: 1. Cold water has a low temperature, making it difficult for it to heat up and evaporate; as a result, less heat is removed, which leads to poor cooling effects for the gas. Moreover, the minerals contained in cold water increase the ash content in asphalt. 2. The low temperature of the cold water causes intense cooling at the bottom of the gas collection pipe; the tar that condenses has a high viscosity, which leads to blockages in the gas collection pipe. Additionally, it is generally used temporarily at the beginning of operation of a new coke oven and when there are faults in the recycled ammonia water system.

Spraying cooled gas with hot ammonia water facilitates the evaporation of ammonia water, enhancing the cooling effect on the gas; at the same time, it prevents the viscosity of the condensed tar from increasing, which could lead to blockages. Furthermore, ammonia water also serves to neutralize taric acid and protect the pipes, and it has lubricating properties that facilitate the flow of tar.

One is corrosion prevention, and the other is the removal of acidic tar. In my opinion, there are still a few points: 1. Circulating ammonia water has to be at a certain temperature; too low a temperature in the initial stage is not ideal, as it can cause blockages in the pipelines, increasing the risk of accidents and the number of purging operations required. 2. Cool it with water; if it is circulated, it will quickly turn into ammonia solution. If the excess water is simply discharged, where does it go? 3. Does ammonia water have a certain temporary emulsifying effect that can emulsify tar, increasing its fluidity, only for the tar to separate out again after entering the clarification tank.

The main purpose is desulfurization; the HPF desulfurization process utilizes ammonia water

Thank you all; I think the idea of the 17th floor is great.