Selection of flow meters for sulfonating agents, chlorinating agents, and nitrating agents in chemical processing processes (sulfonation, chlorination, nitration)
Thread Content
There is a chemical plant that needs to upgrade its sulfonation, chlorination, and nitration production processes. The upgrades must be carried out in accordance with the requirements specified on the website linked below. I have some questions regarding flow meters: 1. In the sulfonation process, concentrated sulfuric acid is used as the sulfonating agent; the pipe diameter is DN50, and the lengths of the pipes before and after it are unknown. The process takes place in an indoor environment, and the flow meter is involved in emergency shutdown procedures but not in material mixing. What type of flow meter would be most suitable for this application? 2. In the chlorination process, chlorine gas is used as the chlorinating agent; the pipe diameter is DN32, and the lengths of the pipes before and after it are unknown. This process takes place outdoors, and the flow meter is involved in both emergency shutdown procedures and material mixing. What type of flow meter should be chosen for this case? 3. In the nitration process, concentrated nitric acid is used as the nitrating agent; the pipe diameter is DN50, and the lengths of the pipes before and after it are unknown. The process takes place in an indoor environment, and the flow meter is involved in emergency shutdown procedures as well as material mixing. What type of flow meter is appropriate for this situation?
Here is the link to the relevant requirements: **Notice from the State Administration of Work Safety on Publishing the List of Key Hazardous Chemical Processes Subject to Strict Supervision http://www.chinasafety.gov.cn/newpage/Contents/Channel_5436/2009/0617/64407/content_64407.htm
I’m not sure if you have read this document carefully; it mentions the basic requirements for safety control as well as the control methods that are advisable to use. Take a close look at this. When selecting instruments, one approach is to choose the most suitable measurement method based on the characteristics of the medium ； One is based on the precision requirements of process control ； At the same time, pay attention to the material of the instruments as well. For those involved in interlocking, it is necessary to ensure compliance with safety standards; pay attention to these factors.
I don’t have any experience in design; this is my first time doing this. I have a general idea of how to proceed, but I’m not sure. Could you help me by suggesting a suitable flow meter based on the conditions mentioned above? Thank you
Can a vortex flow meter be used as a chlorine flow meter? DN32 has a relatively small pipe diameter; what about using a rotameter?
This post was last edited by qugd on 2016-4-8 at 15:52. 1. For concentrated sulfuric acid, an electromagnetic flowmeter is recommended; it offers accurate and reliable measurement, fast response times, and excellent compatibility with the medium. The four-wire electromagnetic flowmeter also offers a rich range of output signals, making it excellent for interlock control. 2. When selecting a flow meter for chlorine, it depends on the required level of measurement accuracy If a precision of around 2% is acceptable, choose a metal rotameter with a PTFE coating ； If the accuracy requirement is around 1%, it is advisable to use a vortex flow meter (a special model with a vortex generator made of silver-plated material) ； If the required precision is around 0.5%, a turbine made of PTFE or a special thermal mass flow meter can be used. For concentrated acids, when the temperature is not high, a conventional electromagnetic flow meter with a PTFE lining can be utilized; if the temperature is higher, a capacitive electromagnetic flow meter with a ceramic lining can be used. Both types of flow meters can meet the requirements of such applications. The diameter is not large, so the straight pipe section isn’t a problem; however, it’s important to ensure that the electromagnetic flowmeter has a reliable grounding.
As a beginner, I have a few questions for you. 1. Regarding the measurement accuracy mentioned in point 2, how can one determine what it is? Is there a specific classification method, such as determining what level of precision is required to achieve certain functions? For something like what I’m designing this time, which is meant to control the ingredient ratios, what level of precision should be used? Could you please help me answer this? 2. Are there any books that provide a detailed introduction to chemical process instruments? Could you recommend a few for me to study?
There is another issue: in this manufacturing process, it is also necessary to use analytical instruments to monitor the medium. Since I am least familiar with such analytical instruments, I haven’t been able to decide which ones to use. Please help me. The media that need to be analyzed are as follows: 1. The impurity content in the nitration products; 2. The impurity content in chlorine gas (water, hydrogen, oxygen, nitrogen trichloride, etc.); 3. The composition of the exhaust gases from the chlorination reaction. Among these, the nitration products mentioned in point 1 need to react with chlorine gas mentioned in point 2. How should I choose the appropriate analytical instruments? The most important thing is to understand what principles are generally followed in selecting analytical instruments I’m not very clear about it
Who can help me answer questions regarding the selection of analytical instruments mentioned above?