Regarding Wu Zheng Company’s ethylene glycol technology

The high-pressure method is currently in the pilot stage and has not yet reached industrial application

Could anyone experienced tell me about the advantages, disadvantages, and future prospects of Wu Zheng technology?

The core technology details have not been made public yet

I have recently researched the medium-high pressure method used by Wu Zheng, and it seems that the publicly available data is quite misleading; yet it has managed to fool so many people… I hope that friends can provide more data such as the reaction temperature, reactor size, and catalyst type, in order to support my conclusions!

What are the physical property parameters of methyl nitrite under high pressure? Have they been determined? If not, it is very dangerous.

Under high pressure, it’s not just the esters that pose a problem; DMO in this state also has a significant impact on the catalyst’s performance, unless the reaction temperature is above 200 degrees.

This is Wu Zheng’s patent; I hope some of the parameters will be useful to you. A process for the high-pressure carbonylation of industrial syngas to produce dimethyl oxalate, followed by hydrogenation to yield ethylene glycol, comprising the following steps: (1) Introducing industrial-grade NO, O2, and methanol into an esterification reactor (9) to carry out the esterification reaction ； The methyl nitrite mixture at the top of the esterification reactor (9) is fed into the carbonylation reactor (1) for carbonylation reaction ； In the esterification reactor (9), part of the acidic alcohol solution in the reactor bottom is recycled to the esterification reactor (9), while part of it is sent to the methanol recovery tower (11) ； The methanol recovered at the top of the methanol recovery tower (11) is partially recycled to the esterification reactor tower (9) for reuse, while the remainder enters the MN recovery tower (15) as a washing liquid ； The waste acid from the bottom of the methanol recovery tower (11) is sent to the nitric acid concentration tower (12) for concentration ； (2) Methyl nitrite from the esterification tower and industrial-grade CO and N2 feeds enter the carbonylation reactor (1), where a carbonylation reaction occurs in the presence of a carbonylation catalyst ； The temperature for the carbonylation reaction is 30–200°C, the reaction pressure is 1–10 MPa, and the gas space velocity is 3000–30000 h‑1 ； (3) The carbonylation product enters the first gas-liquid separator (4) where gas-liquid separation takes place; the gas phase goes to the methanol washing tower (7), while the liquid phase goes to the methanol distillation tower (5) ； The gaseous components at the top of the methanol washing tower (7) are partially recycled to the esterification reactor (9), while the rest are sent as off-gas to the NO recovery tower (13) for recovery ； The liquid phase components from the methanol wash tower (7) enter the methanol distillation tower (5) for distillation and separation ； The methanol and methyl nitrite mixture recovered from the top of the methanol distillation tower (5) is recycled to the esterification reactor tower (9) for reuse, while the heavier components at the bottom of the tower go into the DMO distillation tower (6) ； The DMC product is obtained at the top of the DMO distillation column (6), while the dimethyl oxalate component in the bottom of the column enters the hydrogenation reactor (17) for hydrogenation ； (4) The waste acid from the methanol recovery tower (11) is concentrated in the nitric acid concentration tower (12) until the nitric acid concentration reaches 10–68 wt%, and then it is recycled to the NO recovery tower (13) ； In the NO recovery tower (13), concentrated nitric acid, methanol, and the purge gas from the methanol scrubber tower (7) undergo an esterification regeneration reaction ； The light components in the vapor phase at the top of the NO recovery tower (13) enter the MN recovery tower (15), while the nitric acid waste liquid containing methanol produced at the bottom of the tower is recycled to the methanol recovery tower (11) for further recovery and treatment ； In the MN recovery tower (15), the gaseous feed is washed with recovered methanol before entering the pressure swing adsorption vessel (16); the alcohol solution containing methyl nitrite from the bottom of the MN recovery tower (15) is recycled to the esterification reactor (9) ； The CO2 separated from the pressure swing adsorption tank (16) is discharged outside for treatment, while the recovered N2 and purified CO gas are fed into the carbonylation reactor (1) for reuse ； (5) The dimethyl oxalate component from the bottom of the DMO distillation tower (6) is mixed with industrial hydrogen that has been pressurized by the hydrogenation cycle compressor (25), and then fed into the hydrogenation reactor (17). There, in the presence of a hydrogenation catalyst, hydrogenation reactions take place to produce methanol, ethylene glycol, and other substances ； The hydrogenation reaction temperature is 160–320°C, the reaction pressure is 1–10 MPa, and the liquid space velocity is 1–3 Kg/Kg·h ； (6) The hydrogenation product enters the second gas-liquid separator where gas-liquid separation takes place. The gaseous fraction is pressurized by the hydrogenation cycle compressor (25) and then recycled to the hydrogenation reactor (17); a portion of it goes to the membrane separator (28), where it is processed for recovery before being returned to the hydrogenation reactor (17) for reuse. The liquid fraction, on the other hand, enters the ethylene glycol product tower (24) where it is separated to yield ethylene glycol product.