Discussion on safety distances for liquid ammonia
Thread Content
This post was last edited by 601087456 on 2018-11-14 at 16:55. The desulfurization tower uses liquid ammonia; previously, 20% ammonia water was used, which resulted in a high amount of water vapor and large volumes of water during the post-combustion desulfurization process. Now, by directly introducing liquid ammonia into the circulating liquid at the bottom, the ammonia concentration is increased. This leads to better desulfurization results, less water after desulfurization, and a higher concentration of sulfuric acid. Reduced power transmission output. For a metallurgical enterprise, the general layout is designed in accordance with the Building Code. Now an additional liquid ammonia storage tank is to be installed. How should external safety distances and internal fire protection distances be determined? 1) In accordance with Article 4.3.7 of the Building Design Fire Protection Code, reference should be made to Table 4.4.1 in the same code, which specifies the fire protection distances between full-pressure and semi-refrigerated storage tanks (areas) for liquefied petroleum gas and locations where open flames or sparks may occur, as well as buildings outside the facility. The table outlines the required fire protection distances from related facilities and structures; these distances are required to be at least 27 meters from the outer walls of the industrial enterprise’s buildings. While there is a specification regarding the distance from this industrial enterprise to external enterprises, the distance from its own enclosure walls is not clearly specified. Which requirement should be applied in this case? 2) According to the \"Code for Fire Protection Design of Petrochemical Enterprises\", liquid ammonia is classified as a Class B flammable liquid; should safety and fire separation distances be determined in accordance with this petrochemical code? First, we need to determine whether it falls under the category of hazardous chemical construction projects. According to Article 2 of the \"Measures for the Safety Supervision and Management of Hazardous Chemical Construction Projects\" (issued by the State Administration of Work Safety under Order No. 45 on January 30, 2012, and amended by Order No. 79 on May 27, 2015), these measures apply to the safety management and supervision of new construction, renovation, or expansion projects related to the production or storage of hazardous chemicals within the territory of the People’s Republic of China, as well as chemical engineering projects that generate hazardous chemicals (including projects related to the construction of long-distance pipelines for transporting hazardous chemicals; hereinafter referred to collectively as construction projects). Simply speaking, liquid ammonia falls under the category of hazardous chemicals storage, and thus it is also considered a hazardous chemicals construction project. Furthermore, in accordance with Article 14 of the \"Notice on Further Strengthening the Safety Design Management of Hazardous Chemicals Construction Projects\" (Safety Supervision General Administration Document No. San-76), the design unit shall determine the standards and specifications to be applied for the project based on the characteristics of the hazard sources associated with the construction project and the scope of application of relevant standards and regulations. For construction projects involving the \"two key aspects and one major issue,\" they must meet at least the requirements of the following current standards and specifications, with the strictest safety provisions taking precedence: 1. \"Code for General Layout Design of Industrial Enterprises\" (GB50187) ； 2. «Code for General Layout and Transportation Design of Chemical Enterprises» (GB50489) ； 3. Code for Fire Protection Design of Petrochemical Enterprises (GB50160) ； 4. Code for Fire Protection Design of Oil and Gas Engineering Projects (GB50183) ； 5. Code for Fire Protection Design of Buildings (GB50016) ； 6. \"Code for Design of Oil Storage Tanks\" (GB50074) ； 7. \"Code for Design of Detection and Alarm Systems for Flammable and Toxic Gases in Petrochemical Industries\" (GB50493) ； So, does this mean that the \"Code for Fire Protection Design of Petrochemical Enterprises\" (GB50160) must be followed? I’m a bit confused; I’m not sure if I’m going about this in the wrong way. I would like to seek advice from those who are more experienced in this area – please give me some guidance. :handshake
This post was last edited by 601087456 on 2018-11-14 at 16:55. Two specifications are provided for reference and understanding
In my daily work, I am mainly involved in chemical engineering projects, whether they are new constructions or technical upgrades. For the overall layout design, the construction codes and petrochemical industry standards must be followed; whichever of these two sets of standards requires stricter compliance is to be applied. When constructing new liquid ammonia storage tanks in accordance with these two regulations, it is indeed necessary to comply with the petrochemical industry standards; however, specific details on how to do this should be consulted with the safety supervision authorities.
Safety supervision departments do not go deep enough in making things standardized; in many cases, their response is simply: \"Go and consult the design institute.\" ;P
The moderators, please give some advice; let’s discuss it together
1. First, let’s discuss the applicability of those two documents: Order No. 45 is aimed at chemical construction projects involving hazardous chemicals, and its applicable industry is the chemical sector； Construction projects involving hazardous chemicals used in the general metallurgical industry are subject to Order No. 36 issued by the State Administration of Work Safety, namely the \"Measures for the Supervision and Management of the ‘Three Simultaneities’ Principle for Safety Facilities in Construction Projects\" ； Of course, unless there are different requirements from the local safety supervision agency. Document No. 76 can be applied to the metallurgy industry. 2. Issues related to the two standards: Since Document No. 76 is applicable to the metallurgy industry, it is certain that liquid ammonia storage tanks constitute major hazard sources and should be designed in accordance with petrochemical standards; moreover, they need to be designed in line with the requirements for liquefied hydrocarbons (as stated in Note 2 of Section 6.3.3, liquid ammonia storage tanks are required to meet the same standards as those for liquefied hydrocarbon storage tanks) ； In fact, building codes also clearly state that liquid ammonia storage tanks are classified the same as liquefied petroleum gas tanks, with only a 25% reduction allowed in the required spacing (Building Code Article 4.3.7). The above are personal suggestions for your reference!
Document No. 76 requires that all matters related to the \"two key areas and one major issue\" must be handled in accordance with the strictest standards. Liquid ammonia is considered a hazardous chemical that requires close supervision; even if it does not constitute a major hazard source, it still must comply with the regulations applicable to petrochemicals. Your point that liquid ammonia should be treated as a liquefied hydrocarbon is indeed well-founded. It seems I did not examine the regulations carefully enough: handshake
Also, if liquid ammonia storage tanks are buried underground, the required spacing is reduced by 1/2. Is it reasonable to bury liquid ammonia storage tanks underground? I’ve read a few articles on the advantages and disadvantages of buried storage tanks, and it seems that there is general agreement that burying them is the trend. In Western Europe, where land is extremely expensive, burying tanks helps save a lot of space; as a result, restrictions have been imposed on above-ground storage tanks. There are currently no relevant policies in the country.
It is specified in the standards that the spacing for liquefied petroleum hydrocarbons should be reduced by 25%
The building codes refer to liquid ammonia in terms of liquefied petroleum gas, and the required spacing is reduced by 25% based on that of liquefied petroleum gas; meanwhile, the petrochemical codes require fire separation distances to be determined with reference to liquefied hydrocarbons