Purification Technology Edition: Daily Question [2017-10-18]
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What is the impact of excessive ammonia levels in methanol solutions on the system? Answer: Raw coal contains amino organic compounds, which decompose in the gasifier to produce ammonia. Most of this ammonia is decomposed, with only a small portion remaining undecomposed, and this remaining ammonia is further removed in the ammonia washing tower. Trace amounts of ammonia enter the low-temperature methanol washing system and dissolve in the methanol solution; it is difficult to separate them. Over time, when an excessive amount accumulates, ammonium carbonate crystals form in the water cooler at the top of the regeneration tower. The general requirement for ammonia content is that it should remain below 5–10 mg/l in the methanol returning to the top of the thermal regeneration tower; accordingly, the ammonia content in the methanol after thermal regeneration should be less than 20 mg/l, while the ammonia content in the rich methanol stream in the system should be between 100–200 ppm. If overpressure occurs in the carbon ammonium crystal regeneration tower, the pipeline valve designed to prevent carbon ammonium crystal formation should be opened promptly to eliminate the issue. Furthermore, excessive ammonia levels lead to the formation of ammonium sulfide, which decomposes at the top of the scrubber tower, resulting in elevated hydrogen sulfide levels in the purified gas
Raw coal contains amino organic compounds, which decompose in the gasifier to produce ammonia. Most of this ammonia is decomposed, with only a small portion remaining undecomposed and being further removed in the ammonia washing tower. Trace amounts of ammonia enter the low-temperature methanol washing system and dissolve in the methanol solution; it is difficult to separate them. Over time, as an excessive amount accumulates, ammonium carbonate crystals form in the water cooler at the top of the regeneration tower. The general requirement for ammonia content is that it should remain below 5–10 mg/l in the methanol returning to the top of the thermal regeneration tower; accordingly, the ammonia content in the methanol after thermal regeneration should be less than 20 mg/l, while the ammonia content in the rich methanol stream in the system should be between 100–200 ppm. Excess pressure in the carbon ammonium crystal regeneration tower is generated; the pipeline valve to prevent carbon ammonium crystal formation should be opened promptly to resolve this issue. Furthermore, excessive ammonia levels lead to the formation of ammonium sulfide, which decomposes at the top of the scrubber, resulting in elevated hydrogen sulfide levels in the purified gas.
Answer: Raw coal contains amino organic compounds, which decompose in the gasifier to produce ammonia. Most of this ammonia is decomposed, with only a small portion remaining undecomposed, and this remaining ammonia is further removed in the ammonia washing tower. Trace amounts of ammonia enter the low-temperature methanol washing system and dissolve in the methanol solution; it is difficult to separate them. Over time, as an excessive amount accumulates, ammonium carbonate crystals form in the water cooler at the top of the regeneration tower. The general requirement for ammonia content is that it should remain below 5–10 mg/l in the methanol returning to the top of the thermal regeneration tower; accordingly, the ammonia content in the methanol after thermal regeneration should be less than 20 mg/l, while the ammonia content in the rich methanol stream within the system should be between 100–200 ppm. Excess pressure in the carbon ammonium crystal regeneration tower is generated; the pipeline valve to prevent carbon ammonium crystal formation should be opened promptly to resolve this issue. Furthermore, excessive ammonia levels lead to the formation of ammonium sulfide, which decomposes at the top of the scrubber, resulting in elevated hydrogen sulfide levels in the purified gas.
Answer: Raw coal contains amino organic compounds, which decompose in the gasifier to produce ammonia. Most of this ammonia is decomposed, with only a small portion remaining undecomposed, and this remaining ammonia is further removed in the ammonia washing tower. Trace amounts of ammonia enter the low-temperature methanol washing system and dissolve in the methanol solution; it is difficult to separate them. Over time, as an excessive amount accumulates, ammonium carbonate crystals form in the water cooler at the top of the regeneration tower. The general requirement for ammonia content is that it should remain below 5–10 mg/l in the methanol returning to the top of the thermal regeneration tower; accordingly, the ammonia content in the methanol after thermal regeneration should be less than 20 mg/l, while the ammonia content in the rich methanol stream within the system should be between 100–200 ppm. Excess pressure in the carbon ammonium crystal regeneration tower is generated; the pipeline valve to prevent carbon ammonium crystal formation should be opened promptly to resolve this issue. Furthermore, excessive ammonia levels lead to the formation of ammonium sulfide, which decomposes at the top of the scrubber, resulting in elevated hydrogen sulfide levels in the purified gas.
Answer: Raw coal contains amino organic compounds, which decompose in the gasifier to produce ammonia. Most of this ammonia is decomposed, with only a small portion remaining undecomposed, and this remaining ammonia is further removed in the ammonia washing tower. Trace amounts of ammonia enter the low-temperature methanol washing system and dissolve in the methanol solution; it is difficult to separate them. Over time, as an excessive amount accumulates, ammonium carbonate crystals form in the water cooler at the top of the regeneration tower. The general requirement for ammonia content is that it should remain below 5–10 mg/l in the methanol returning to the top of the thermal regeneration tower; accordingly, the ammonia content in the methanol after thermal regeneration should be less than 20 mg/l, while the ammonia content in the rich methanol stream within the system should be between 100–200 ppm. Excess pressure in the carbon ammonium crystal regeneration tower is generated; the pipeline valve to prevent carbon ammonium crystal formation should be opened promptly to resolve this issue. Furthermore, excessive ammonia levels lead to the formation of ammonium sulfide, which decomposes at the top of the scrubber, resulting in elevated hydrogen sulfide levels in the purified gas.
If you’re referring to the production aspect, different systems vary, and the main impacts are corrosion and equipment voltage changes, which pose safety risks
Raw coal contains amino organic compounds, which decompose in the gasifier to produce ammonia. Most of this ammonia is decomposed, with only a small portion remaining undecomposed and being further removed in the ammonia washing tower. Trace amounts of ammonia enter the low-temperature methanol washing system and dissolve in the methanol solution; it is difficult to separate them. Over time, as an excessive amount accumulates, ammonium carbonate crystals form in the water cooler at the top of the regeneration tower. The general requirement for ammonia content is that it should remain below 5–10 mg/l in the methanol returning to the top of the thermal regeneration tower; accordingly, the ammonia content in the methanol after thermal regeneration should be less than 20 mg/l, while the ammonia content in the rich methanol stream in the system should be between 100–200 ppm. Excess pressure in the carbon ammonium crystal regeneration tower is generated; the pipeline valve to prevent carbon ammonium crystal formation should be opened promptly to resolve this issue. Furthermore, excessive ammonia levels lead to the formation of ammonium sulfide, which decomposes at the top of the scrubber, resulting in elevated hydrogen sulfide levels in the purified gas.
Ammonia from the conversion system becomes concentrated in methanol, preventing it from being completely stripped in the thermal regeneration tower. It reacts with hydrogen sulfide to form ammonium sulfide ((NH4)2S), which is present in the methanol after thermal regeneration. In the carbon dioxide absorption tower, ((NH4)2S) decomposes into hydrogen sulfide, resulting in an excessive sulfur content in the purified gas. Of course, an appropriate amount of ammonia is beneficial for the corrosion protection of carbon steel equipment.
It affects product quality and increases consumption.
1. Reduce the efficiency of methanol absorption 2. Block the acidic gas pathway
Raw coal contains amino organic compounds, which decompose in the gasifier to produce ammonia. Most of this ammonia is decomposed, with only a small portion remaining undecomposed and being further removed in the ammonia washing tower. Trace amounts of ammonia enter the low-temperature methanol washing system and dissolve in the methanol solution; it is difficult to separate them. Over time, as an excessive amount accumulates, ammonium carbonate crystals form in the water cooler at the top of the regeneration tower. The general requirement for ammonia content is that it should remain below 5–10 mg/l in the methanol returning to the top of the thermal regeneration tower; accordingly, the ammonia content in the methanol after thermal regeneration should be less than 20 mg/l, while the ammonia content in the rich methanol stream in the system should be between 100–200 ppm. Excess pressure in the carbon ammonium crystal regeneration tower is generated; the pipeline valve to prevent carbon ammonium crystal formation should be opened promptly to resolve this issue. Furthermore, excessive ammonia levels lead to the formation of ammonium sulfide, which decomposes at the top of the scrubber, resulting in elevated hydrogen sulfide levels in the purified gas.