Introduction to the structure of the isopropyl alcohol dehydration unit—save this for future reference!

What is the structure of an isopropyl alcohol dehydration unit? Let’s take a brief look together.

The isopropanol dehydration unit comprises a feed‑treatment section, a membrane‑separation section, a permeate‑treatment section, and a retentate‑treatment section, as follows: the feed‑treatment section includes a storage tank, fluid‑pumping equipment, and heat‑exchanging equipment; the heat‑exchanging equipment is equipped with a feed inlet, a feed outlet, a heat‑transfer‑medium inlet, and a heat‑transfer‑medium outlet. The membrane‑separation section has a feed inlet, a retentate outlet, and a permeate outlet; the heat‑transfer‑medium inlet of the heat‑exchanging equipment is connected to the retentate outlet of the membrane‑separation section, while its heat‑transfer‑medium outlet is connected to the retentate‑treatment section, and the permeate outlet of the membrane‑separation section is connected to the permeate‑treatment section. In the method for dehydrating and purifying isopropanol using this unit, the following steps are carried out: the aqueous isopropanol feed is buffered in the storage tank before entering the heat‑exchanging equipment, where it is preheated using heat supplied by the heat‑transfer medium; the preheated feed then enters the membrane‑separation section in either vapor or liquid form. The permeate (isopropanol) is separated by the membrane‑separation device and conveyed as a heat‑transfer medium to the heat exchanger, where it exchanges heat with the feed; the resulting permeate is subsequently collected and treated by the permeate‑treatment unit, yielding a qualified isopropanol product. The permeate generated by the membrane‑separation section—namely, water vapor—is routed to the market‑grade permeate‑treatment unit, where it is condensed and buffered before being discharged from the system.

The aforementioned approach enables the dehydration and purification of aqueous isopropanol, with a coupled-loop design that effectively manages and recycles the system’s energy, significantly reducing energy consumption and lowering operational environmental costs. It fully leverages the advantages of membrane separation technology, replacing conventional distillation columns for isopropanol dehydration. The integrated unit‑based refining process is simple to operate, runs smoothly, and supports continuous operation and production, while the associated equipment occupies a small footprint and requires low capital investment.

What are the specific implementation methods for dehydrating isopropyl alcohol? Let’s take a brief look together below.

The isopropyl alcohol dehydration and purification method comprises conveying a water-containing isopropyl alcohol feedstock at a mass flow rate of 800–1200 kg/h to a heat exchanger for preheating; after the preheated feedstock is vaporized at 70–90°C, it enters a membrane separation module at a pressure of 0.2–0.4 MPa and a temperature of 100–130°C for dehydration. The dehydrated isopropyl alcohol product vapor (i.e., the permeate) is first routed to a heat exchanger to exchange heat with the feedstock, then condensed and collected as the final isopropyl alcohol product. To ensure product quality, in the present invention’s isopropyl alcohol dehydration and purification process, the water content of the feedstock does not exceed 10% by mass. The preferred preheating temperature of the feedstock is 120°C ± 10°C.

In the loop design of the process, the coupling ring design effectively enables energy recovery, significantly reducing energy consumption and lowering operating costs.