Qualitative issues of liquid ammonia storage tanks

There are already posts on this forum discussing liquid ammonia, and I’ve said it before: liquid ammonia should be treated as a liquid hydrocarbon! You could totally reply to that post; I don’t know why you had to start a new one! http://bbs.hcbbs.com/thread-144370-1-1.html Additionally, your second point is completely wrong! This post was last edited by mine on 2008-1-28 19:18.]

Liquid ammonia exists in a gaseous state at normal temperature and pressure; it cannot be treated as a liquid!

On the list of hazardous chemicals, liquid ammonia is classified as a toxic gas. As mentioned on the second floor, it is similar to liquefied petroleum gas in that it is a flammable substance under pressure; its main hazard, of course, is its toxicity

Personally, I believe that for ammonia storage tanks, whether they contain gaseous or liquid ammonia, safety management should be carried out according to the highest applicable standards

Petroleum regulations: The fire separation distance between liquid ammonia storage tanks is determined in accordance with the requirements for liquefied hydrocarbons

Liquid ammonia storage tanks are pressure vessels and cannot meet the requirements of atmospheric-pressure liquid storage tanks

1. Storage at atmospheric pressure: Pressure of 100–500 mmH2O, temperature below -33°C. The tanks are usually very large, with a volume of over 1000 m3. To maintain the pressure and temperature inside the tanks, a refrigeration system is required, along with a mechanism for recovering the ammonia vapor that evaporates. A liquid ammonia pump is required for pressurization when delivering ammonia. It is expensive and is generally used in large-scale chemical plants. 2. Storage under pressure: The temperature is above 10°C; the tank has a small volume, and it can be in spherical or cylindrical shape. It is cost-effective and can also be used as an intermediate tank. Petroleum regulations: The fire separation distance between liquid ammonia storage tanks is determined in accordance with the requirements for liquefied hydrocarbons; in the event of a leak, large amounts of water must be used to dilute it.

1. The petrochemical regulations only specify that the fire separation distance between liquid ammonia storage tanks should be the same as that for liquefied hydrocarbon storage tanks; they do not state that the fire separation distance between liquid ammonia storage tanks and other adjacent facilities should also be the same as that for liquefied hydrocarbon storage tanks. So, how should the fire separation distance between liquid ammonia storage tanks and adjacent facilities be determined? II. Regarding the fire separation requirements for liquid ammonia storage tanks, there are currently two main standards: one is the Building Code, and the other is the Petrochemical Code. But both have their respective areas of application. Assuming what the person from Layer XX said is true, liquid ammonia should be treated as a liquefied hydrocarbon storage tank; however, in enterprises where petrochemical standards do not apply, only building codes can be used for regulation. But the building codes only specify aspects such as \"flammable liquid storage tanks, flammable gas storage tanks, liquefied petroleum gas, and storage areas for flammable materials,\" and they do not address liquefied hydrocarbons (some might say that liquefied petroleum gas is a type of liquefied hydrocarbon). Then why doesn’t the building code specify the spacing for liquefied hydrocarbons directly, but only addresses liquefied petroleum gas? III. In the building codes, there are provisions regarding the fire separation distances for flammable gas storage tanks that apply to liquid oxygen and liquid hydrogen; these substances are also in a liquefied state under pressure (although freezing is also used in some cases). Since they are considered flammable gases, why then do the building codes take into account the liquefied state and specify fire separation distances for them? Furthermore, the petrochemical regulations and building codes mention \"ammonia\" as an example of a material prone to fire, without specifying whether it refers to liquid ammonia or gaseous ammonia. However, liquid ammonia will definitely vaporize upon leakage, and it is the gaseous ammonia that poses the main danger. For this reason, when considering fire separation distances, why can’t we treat them as flammable gases?

Regarding fire separation distances, they are determined in accordance with liquefied hydrocarbons, as specified in Regulation 2.0.2 on chemical safety, taking into account the characteristics of liquefied hydrocarbons. In the classification of combustible gases. Class B. However, liquid ammonia is primarily treated as a toxic gas.

I don’t know what you mean; the petrochemical regulations do not specify that liquid ammonia should be treated as a liquefied hydrocarbon. Take a closer look at clause 2.0.2 you mentioned. We are currently discussing how to determine the fire separation distances, not what type of gas liquid ammonia is. You mentioned treating it as a toxic gas, but I really don’t know what the fire separation distance should be for toxic gases, nor are there any standards that specify such distances. Besides, liquid ammonia is treated as a liquefied hydrocarbon; the petrochemical regulations only specify that storage tanks should be treated in accordance with these rules, but they do not state explicitly that other items should also be treated as liquefied hydrocarbons. Take a look at section 2.0.1 – among the combustible gases listed are ammonia and carbon monoxide. Is carbon monoxide a toxic gas? Then, regarding the fire separation requirements for liquid ammonia, which category should it be classified under? Please be informed as well.

Personally, I believe that for ammonia storage tanks, whether they contain gaseous or liquid ammonia, safety management should be carried out according to the highest applicable standards

“According to building codes, ammonia is classified as a Class B flammable substance. Yesterday, I saw on a forum someone suggesting that liquid ammonia should be treated as a liquid, and in that case its fire hazard category would be Class A. It makes sense. ” There is a problem with this statement. The response from the drafting team for the regulatory guidelines was that equipment containing liquid ammonia in storage tanks should be classified according to the hazard level of Class B fires

We have also been troubled by this issue.

Liquid ammonia can be treated as a flammable liquid; standards already exist to classify it, but they are still under approval process. In this approval draft, liquid ammonia is classified as Category B liquid

The issue regarding liquid ammonia has not yet been resolved; the building codes are currently being revised. Let’s all send emails or suggestions to the revision team. To all relevant organizations and experts: In accordance with the requirements set out in the Notice issued by the Ministry of Construction (Document No. Jianbiao 125), the Tianjin Fire Research Institute of the Ministry of Public Security, together with other relevant organizations, has completed the draft for partial revisions to the Code for Fire Protection Design of Buildings. This draft is now sent to you. Kindly assist in organizing relevant personnel to conduct research and discussions, submit their opinions, and compile these opinions before June 1, 2008, to the revision team of the \"Code for Fire Protection Design of Buildings\". If you propose any revisions, please explain the reasons and kindly send along the relevant background materials. When replying, please indicate the contact person and phone number for further communication. Thank you for your strong support! Mailing address: No. 110, Weijin South Road, Nankai District, Tianjin City, Postal Code: 300381. Contact persons: Wang Zongcun, Kan Qiang. Phone: 022-23383501-2405. Fax: 022-23383514. Email: wangzongcun@tfri.com.cn ； kanqiang@tfri.com.cn Attachment: 1 \"Code for Fire Protection Design of Buildings\" (Draft for partial revision and comments) 2 Feedback form for the \"Code for Fire Protection Design of Buildings\" (Draft for partial revision and comments) **Standard Management Group for the Code for Fire Protection Design of Buildings April 17, 2008

With storage at atmospheric pressure, does the ammonia refrigeration compressor associated with the liquid ammonia tank operate 24 hours a day? What size refrigeration compressor should be used for a 5,000 cubic meter spherical tank? What is the typical filling factor for storage tanks that are stored under pressure? And why is a cooling system not required for tanks that are under pressure?

Liquid ammonia is indeed quite special; according to the regulations, it is classified as a Class B1 flammable liquid, and it is the most special substance among Class B1 flammable liquids. Logically, the flash point of liquid ammonia is meaningless as it does not conform to its definition. The regulations state that while the fire separation distance between liquid ammonia storage tanks should be in accordance with the requirements for liquefied hydrocarbons, there are no such requirements for the fire separation distance from other storage tanks or facilities; in such cases, it should be determined based on the criteria for Class B flammable liquids.