Issues related to the selection of low-temperature ethylene pumps
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Here’s the situation: I have a new project that involves low-temperature ethylene, which needs to be transferred from a low-temperature tank to the reactor in the plant. I’m facing some difficulties in selecting the appropriate pump for this purpose. I would appreciate it if you could help me out; thank you in advance. The flow process is as follows: Low-temperature ethylene tank (0.6 MPA) – Pump (pressures the fluid to 2.2 MPA) – Vaporizer (at room temperature) – Reactor (2.1 MPA). The specific requirements are as follows: flow rate of 950–1000 KG/H at a temperature of -69°C; the pressure inside the ethylene tank is 0.6 MPA (gauge); the desired outlet pressure is 2.2 MPA (gauge). Based on these requirements, my possible options are as follows: 1) Use a multi-stage pump, but its efficiency is too low. Moreover, manufacturers say that horizontal multi-stage pumps are difficult to find for such low flow rates (the flow rate, when converted to standard cubic meters, is around 2.0 NM3/H). Additionally, it’s not easy to install such pumps at the site due to issues related to net positive suction head. The manufacturer suggested using their cartridge pumps, but considering the net positive suction head requirements, those pumps would also need to be installed underground. So I’m not interested in this option. 2) Use a reciprocating pump. In this case, the pressure at the vaporizer outlet could be used as a signal to control the speed of the reciprocating pump via an inverter. The flow rate could then be adjusted by controlling the pump’s speed. This type of pump also helps to address the issue of cavitation. I hope you can discuss whether this second option is feasible, taking into account factors such as safety, reliability, and cost-effectiveness. Thank you very much!
Our factory uses TTMC cartridge multi-stage pumps, made by Sulzer; they work fine, but the pressure they can generate isn’t as high as yours.
1. In terms of price, barrel bag pumps are definitely much more expensive, but they are indeed very suitable for applications that require low temperatures and high resistance to cavitation； Our company makes extensive use of many low-temperature storage facilities (C3, C4), especially when cleaning tanks, as there is less residual material left in the tanks ； 2. Installing a frequency converter on a reciprocating pump can indeed address the issue of cavitation (reciprocating pumps do not experience cavitation issues), but due to changes in its rotational inertial torque and reverse angle, it has a significant impact on the pump’s lifespan ； Moreover, the leakage problem of reciprocating pumps cannot be resolved, and there are many safety issues associated with them. 3. Since I don’t have any information on high-speed pumps available, I suggest considering those; our factory has used them in gas separation units, and they prove to be much more stable. However, if the operating conditions change significantly, that factor should be taken into account
May I ask, which domestic company is relatively good for using cartridge-type multi-stage pumps to handle olefins, in terms of price and operating conditions?