44results about How to "Extend the period of stable operation" patented technology

The invention provides a method for flushing a reverse osmosis (RS) membrane, which aims at the problems of filtration surface contamination and first-section contamination of a reverse osmosis system membrane caused by high salt, organic colloidal silica, high molecular organic contaminants and microbiological remains during reverse osmosis treatment of olefin production process water, circulating cooling water and sewerage. In the method, positive flushing and concentrated water side reverse flushing are adopted, and agents such as an organic solvent and the like are matched, so hydraulic flushing is formed on the RO membrane filtration surface, blocking contaminants on the membrane surface which cannot be chemically removed are obviously removed, the problem of the first-section contamination of a membrane system is solved, and stable running period of the RO system is prolonged.

The present invention provides a wax oil hydrotreating method comprising the following steps: hydrogen gas is sent into a wax oil raw material by pores with the average pore size in nanometer-size to obtain hydrogen-containing wax oil; and the hydrogen-containing wax oil is fed into a tubular reactor for contacting with a hydrogenation catalyst filled in the tubular reactor under conditions of liquid-phase hydrogenation processing. Even hydrogen oil ratio is lower, and space velocity is higher, sulfur and nitrogen in the wax oil can be effectively removed, part of aromatics are saturated, hydrogen-carbon atom ratio of the wax oil can be improved, and a high-quality catalytic cracker raw material can be obtained.

A method for removing hydrogen sulfide from a mixed gas containing low-concentration hydrogen sulfide gas is provided, comprising: providing an absorbing liquid, the absorbing liquid being selected from N-methylglycolamine solution, monoethanolamine solution, diethanolamine Solution, and their mixture; under the absolute pressure of 0.05-0.30MPa, the absorption liquid at 18-42°C is contacted with the mixed gas containing low-concentration hydrogen sulfide gas at 20-52°C, and the mixed gas is sequentially counter-current Absorption and swirl absorption to reduce the concentration of hydrogen sulfide in the mixed gas to 10ppm or lower; and perform swirl gas-liquid separation on the mixed gas entraining the absorption liquid. Also provided is a device for removing hydrogen sulfide from a mixed gas containing low-concentration hydrogen sulfide gas.

The invention discloses a device, a system and a process for formaldehyde concentrating. The device is a formaldehyde concentrating vacuum separator, which is a circular cylinder structure and which is provided with a jacket on the external wall. One end of the circular cylinder structure is provided with a gas phase outlet, and the other end is provided with a liquid phase outlet. The cylinder wall of the circular cylinder structure is provided with a material inlet pipe. The material discharging direction of the material inlet pipe is tangent to the wall of the circular cylinder structure. The material inlet pipe is adjacent to the gas phase outlet, and the cylinder wall of the circular cylinder structure is provided with an annular liquid retaining ring the center of which is on the axis of the circular cylinder structure. The liquid retaining ring is located between the material inlet pipe and the gas phase outlet. The gas phase outlet is provided with a gas discharging pipe. The gas inlet of the gas discharging pipe is between the material inlet pipe and the liquid phase outlet. The device enables greatly improved concentration separation efficiency and reduces the recovery amount of lean formaldehyde and steam consumption.

The invention relates to a method for producing caprolactam by methylbenzene, which comprises the following processes of oxidation, esterification, hydrogenation, distillation, amidation, hydrolyzing and refining, wherein in the oxidation process, the methylbenzene is completely converted into benzoic acid by adopting an ester solvent; in the esterification process, the benzoic acid dissolved in ester reacts with alcohol to form corresponding benzoate; in the hydrogenation reaction, a benzene ring of the benzoate is hydrogenated till saturation to form cyclohexanecarboxylate in a fixed bed reactor, and the cyclohexanecarboxylate enters the amidation process; and in the amidation process, the cyclohexanecarboxylate reacts with nitrosyl sulfuric acid, the reaction product is subjected to hydrolyzing rearrangement in the sulfuric acid to form the caprolactam by refining. In the method, the conventional rectification of the benzoic acid is changed into the rectification of the benzoate, agranular catalyst replaces the original powder palladium-carbon catalyst, the processes of catalyst sedimentation, centrifugal separation and the like are reduced, the generation of ammonium sulfate is reduced, and dimethyl sulfate serving as a by-product is produced simultaneously.

The invention relates to a circulating CO shift process of a saturation tower. The circulating CO shift process comprises the following steps that a coarse synthetic gas from a pulverized coal gasification unit is divided into two branches, the first branch of coarse synthetic gas is moisturized and heated in the saturation tower and then mixed with high pressure steam and a first branch of primary shift gas and replenished with medium-pressure boiler water, and then the obtained mixture is fed into a No.1 shift furnace for shift reaction, the obtained primary shift gas is divided into two branches after heat exchange, the second branch of primary shift gas is mixed with the first branch of coarse synthetic gas to obtain a primary shift mixed gas, the primary shift mixed gas is mixed and replenished with medium-pressure steam and then fed into a No.2 shift furnace for continuous shift reaction, and the secondary shift gas is fed into a No.3 shift furnace for reaction after heat exchange. The operation of dividing the coarse synthetic gas and the primary shift gas into branches in the circulating CO shift process, so that the CO concentration entering the shift furnaces is effectively reduced; the operating temperatures of the shift furnaces are low, and the operating environment of a catalyst is mild, so that the service life of the catalyst and the operation period of the device are prolonged; and meanwhile, the amount of steam used is reduced, and the effects of energy conservation and consumption reduction are remarkable.

The invention discloses a dimethyl sulfide oxidation method. The method comprises causing a liquid mixture to pass through a catalyst bed layer filled with at least one titanium silicalite molecular sieve under the conditions of oxidation reaction, wherein the liquid mixture contains dimethyl sulfide and at least one oxidizing agent. The method comprises switching the flow direction of the liquid mixture in the catalyst bed layer when the catalytic activity of the titanium silicalite molecular sieve in the catalyst bed layer is lower than an expected value, wherein with the flowing direction of the liquid mixture in the catalyst bed layer prior to the switching as the standard, the liquid mixture performs reverse flowing in the catalyst bed layer after the switching. According to the method, even if long-time continuous running is performed, the activity of the catalyst can be maintained within a high range, so that the stable running time of a device is effectively prolonged, and the running cost of the device is reduced. In addition, the method is simple, convenient, practical and favorable for industrial production and application.

The invention relates to the field of industrial waste water treatment and particularly relates to a treatment and recycle method of a phosphoric acid waste liquid. In the method, the phosphoric acid waste liquid is successively subjected to micro-filtration, anion exchange, cation exchange and two-stage membrane distillation for recycling the phosphoric acid therefrom. The treatment and recycle method of the phosphoric acid waste liquid, in which the processes comprising the micro-filtration, the anion exchange, the cation exchange, primary membrane distillation and secondary membrane distillation are employed, can be used for treating the phosphoric acid waste liquids generated in production processes of various industries to recycle the phosphoric acid therefrom. The method not only saves energy but also protects natural ecological environment.

The invention discloses a full-automatic control nanofiltration membrane online strong flushing method, for solving the problem that when nanofiltration membrane is used for treating reverse osmosis concentrate of printing and dyeing wastewater, a membrane flux attenuation rate is high due to high-concentration chloride, persistent organic pollutants, aluminum salts and the like; the method comprises production operation of a nanofiltration membrane system and strong flushing operation; pollutants on the surface of the nanofiltration membrane is periodically flushed according to set time of a membrane system controller; according to the full-automatic control nanofiltration membrane online strong flushing method, the nanofiltration membrane core is periodically strongly flushed by raw water, so that pollution to the membrane surface can be effectively relieved, thus playing roles in prolonging stable operating period of the membrane system, automatically controlling a whole process, and being simple, convenient, short in time and significant in effect.