The unloading of butadiene uses a process that combines compressors and pumps
Thread Content
This post was last edited by wenyan_li08 on 2015-8-3 at 14:31. Requirements for unloading dibutylene: The gaseous phase coming from the storage tank is pressurized and unloaded using a compressor, while the liquid phase at the outlet of the tank truck is pumped out. 1. I don’t quite understand the advantages of combining these two methods – can it also handle the materials in the tank trucks completely? 2. Since the pump cannot empty the tank, I don’t understand how the contents can be completely removed. Also, after unloading is complete, how is the gas phase in the tank removed? 3. In the case of intermittent unloading, is it necessary to purge the pipelines at the pump inlet and outlet, as well as the gas phase lines and other unloading pipelines, with N2 after the unloading is completed? 4. How should the capacity of the compressor be selected? 5. The temperature is relatively high during the compression process by the compressor. However, due to the properties of butadiene itself, it tends to polymerize easily at high temperatures. So how can this temperature be managed and controlled? Since I have no experience in this area, after reading some materials I only have a very vague understanding of it. I hope experts can help me clarify it; I would be very grateful.
Bro, I’ve never been involved in the direct unloading of butadiene, but I’ve worked in warehouse areas for ten years. Based on your questions, I’ll give some simple answers in the hope that they can help you. 1. Butadiene is a highly dangerous substance, which is why pressure tank trucks are used; it’s not possible to clean it thoroughly using pumps without applying pressure. Negative pressure is generated, causing the butadiene to vaporize; therefore, both need to be combined in order to achieve complete evacuation. 2. The amount of gas phase in the tank trucks remains constant; aside from some loss in the first truck, the subsequent tanks retain the same amount of gas phase, so there’s no need to worry about losses. Charter vehicles are not cleaned. 3. It should be swept clean; otherwise, high temperatures will cause substances to accumulate in the pipes. 4. The air compressor has been designed by a specialized institute, so pressurization does not result in a significant increase in temperature. 5. The answer is somewhat subjective; I hope it can help you
This is a standard configuration for liquefied hydrocarbon unloading. In the initial stage, the compressor draws out the gas phase from the storage tank to pressurize the tank truck, while a pump is used to draw out the liquid phase from the tank truck. When the liquid level drops to a certain level, a compressor is used to draw the gas phase in the tank truck back to the storage tank, simultaneously vaporizing the liquid phase in the tank truck so that it can return to the storage tank in gaseous form. Finally, it is sufficient to ensure the appropriate pressure inside the tank truck; generally, a pressure of 1 barg is required if high standards are applied. In this way, the material inside the tank truck can be emptied as completely as possible. 2. First, use a pump to extract as much of the liquid phase as possible, and then use a compressor to extract the gas phase. 3. For butadiene, to prevent self-polymerization, it is best to purge it with nitrogen before sending it to the flare. 4. The processing capacity of the compressor is primarily determined by the unloading time. Calculations are carried out based on the acceptable unloading time and the pressure required in the tank to be emptied; of course, the selection of the pump also needs to be taken into account (typically, it takes 20–30 minutes for a pump to evacuate the liquid). 5. During the compression process, a condensing medium can be added to facilitate condensation and prevent self-polymerization. I hope this helps you.
Your answer is very comprehensive. There is one more question: does the pipeline require special configuration during reverse drawing? Or go back the way we came, simply turning the compressor outlet into the inlet and the inlet into the outlet?