Abstract: The invention relates to a method of circular use of waste brine produced in the manufacture process of MDI, comprising the following steps: (1) the waste brine produced in the manufacture process of MDI is subjected to a high-gravity extraction and then to a column extraction, wherein said waste brine contains aniline, diaminodiphenylmethane and polyamine; (2) the waste brine from step (1) is transmitted to a stripping tower for steam stripping; (3) the waste brine from the stripping tower of step (2) and a chemical oxidant are transmitted to an oxidation reactor to which air is blown for aeration; (4) the waste brine after the treatment of step (3) is transmitted to an absorption tower for absorption. The invention makes the salt water have TOC of less than 8 ppm and TN of less than 2.5 ppm and achieves regeneration of resources in the waste brine such as sodium chloride and water and the like for circular use.

Abstract: The present invention provides a flow duct type jet reactor and a process for preparing isocyanates using it. The flow duct type jet reactor situates flow ducts in inner feed pipe which form whirlpool and reinforce vortex, thereby amine steam rapidly admixes and reacts with phosgene, and the byproducts are reduced. In addition, the present process uses a jet-absorption apparatus which rapidly cools the high temperature gas discharged from the reactor to a temperature at which the product is thermally stable, and at the same time provides negative pressure for the reaction process of the system, and thus saving bulky vacuum system.

Abstract: A hole-jetting type mixer-reactor, comprises the following parts: a first feeding port, a second feeding port, an outer casing, an inner casing, jet holes and a mixing reaction zone. The inner casing is inside the outer casing, and the lower portion of the outer casing forms a buffer chamber with the inner casing. The first feeding port connects with the inner casing to constitute one flow channel, and the second feeding port connects with the buffer chamber to form the other flow channel. The jet holes are on the wall of the inner casing situated at lower portion of the buffer chamber. The mixing reaction zone is inside the inner casing below the jet holes. The cross section of the inner casing is rectangular or rectangle-like. The mixer-reactor can achieve a fast mixing of two reactant streams which reacts with instantaneous, complicated parallel or consecutive competing reactions. The time scale of the mixing process is several milliseconds.

Abstract: The present invention provides a flow duct type jet reactor and a process for preparing isocyanates using it. The flow duct type jet reactor situates flow ducts in inner feed pipe which form whirlpool and reinforce vortex, thereby amine steam rapidly admixes and reacts with phosgene, and the byproducts are reduced. In addition, the present process uses a jet-absorption apparatus which rapidly cools the high temperature gas discharged from the reactor to a temperature at which the product is thermally stable, and at the same time provides negative pressure for the reaction process of the system, and thus saving bulky vacuum system.

Abstract: The present invention provides a method of preparing polymethylene-polyphenyl-polyamine (briefly referred to as polyamine, DAM), in which a high gravity rotating bed is used as the mixing reactor of formaldehyde and aniline hydrochloride, the mixing solution of aniline hydrochloride and circulation solution and the formaldehyde are fed into the high gravity rotating bed reactor proportionally to carry out mixing and condensation reaction under a condition of a very high gravity; the materials leaving the high gravity rotating bed reactor is introduced into a stirred vessel to proceed with the pre-condensation reaction and obtain a condensation solution; and the process steps of heating, molecular rearrangement, neutralization, water washing and purification, etc. are completed to obtain the refined DAM.

Abstract: The present invention relates to a hole-jetting type reactor and its applications, in particular to a process for the production of isocyanates by the phosgenation of aliphatic or aromatic diamines or triamines in the gas phase using this reactor. The present invention achieves a good mixing and reacting result of the gas-phase phosgenation reaction at a high temperature by improving the mixing of reactants in the reactor to reduce the possibility of forming swirls and eliminate negative pressure produced at a local jet area, which can finally reduce back-mixing and formation of solid by-products.

Abstract: The present invention provides a method of preparing polymethylene-polyphenyl-polyamine (briefly referred to as polyamine, DAM), in which a high gravity rotating bed is used as the mixing reactor of formaldehyde and aniline hydrochloride, the mixing solution of aniline hydrochloride and circulation solution and the formaldehyde are fed into the high gravity rotating bed reactor proportionally to carry out mixing and condensation reaction under a condition of a very high gravity; the materials leaving the high gravity rotating bed reactor is introduced into a stirred vessel to proceed with the pre-condensation reaction and obtain a condensation solution; and the process steps of heating, molecular rearrangement, neutralization, water washing and purification, etc. are completed to obtain the refined DAM.

Abstract: A hole-jetting type mixer-reactor, comprises the following parts: a first feeding port, a second feeding port, an outer casing, an inner casing, jet holes and a mixing reaction zone. The inner casing is inside the outer casing, and the lower portion of the outer casing forms a buffer chamber with the inner casing. The first feeding port connects with the inner casing to constitute one flow channel, and the second feeding port connects with the buffer chamber to form the other flow channel. The jet holes are on the wall of the inner casing situated at lower portion of the buffer chamber. The mixing reaction zone is inside the inner casing below the jet holes. The cross section of the inner casing is rectangular or rectangle-like. The mixer-reactor can achieve a fast mixing of two reactant streams which reacts with instantaneous, complicated parallel or consecutive competing reactions. The time scale of the mixing process is several milliseconds.