750results about How to "Reduce nitrogen content" patented technology

A preparation process of polyimide aerogels that composed of aromatic dianhydrides and aromatic diamines or a combined aromatic and aliphatic diamines is described. Also descried is a process to produce carbon aerogels derived from polyimide aerogel composed of a rigid aromatic diamine and an aromatic dianhydride. Finally, the processes to produce carbon aerogels or xerogel-aerogel hybrid, both of which impregnated with highly dispersed transition metal clusters, and metal carbide aerogels, deriving from the polyimide aerogels composed of a rigid aromatic diamine and an aromatic dianhydride, are described. The polyimide aerogels and the polyimide aerogel derivatives consist of interconnecting mesopores with average pore size at 10 to 30 nm and a mono-dispersed pore size distribution. The gel density could be as low as 0.008 g / cc and accessible surface area as high as 1300 m<2> / g.

A preparation process of polyimide aerogels that composed of aromatic dianhydrides and aromatic diamines or a combined aromatic and aliphatic diamines is described. Also descried is a process to produce carbon aerogels derived from polyimide aerogel composed of a rigid aromatic diamine and an aromatic dianhydride. Finally, the processes to produce carbon aerogels or xerogel-aerogel hybrid, both of which impregnated with highly dispersed transition metal clusters, and metal carbide aerogels, deriving from the polyimide aerogels composed of a rigid aromatic diamine and an aromatic dianhydride, are described. The polyimide aerogels and the polyimide aerogel derivatives consist of interconnecting mesopores with average pore size at 10 to 30 nm and a mono-dispersed pore size distribution. The gel density could be as low as 0.008 g / cc and accessible surface area as high as 1300 m2 / g.

The invention relates to a high-temperature solid-phase synthesis method of high-purity silicon carbide powder. The high-temperature solid-phase synthesis method comprises the following procedures of: material compounding: uniformly mixing high-purity Si powder and high-purity C powder according to the molar ratio of (1:1)-(1.5:1); high-vacuum heat treatment: placing high-purity Si and C powder into a crucible, placing the crucible in a heating furnace, vacuumizing a growth chamber of the heating furnace to be below 9*10<-4> Pa, increasing the temperature to 600-1300 DEG C and maintaining the temperature for more than 2 h; inert gas cleaning: charging a high-purity inert gas under first specified pressure into the growth chamber, maintaining for more than 1 h, vacuumizing the growth chamber to be below 9*10<-3> Pa once again, and repeating the procedure more than twice; and high-temperature synthesis: in the present of high-purity inert gas under a second specified pressure, reacting for more than 2 h at the reaction temperature of 1500-2500 DEG C, and cooling to room temperature to obtain the high-purity silicon carbide powder with nitrogen content below 15 ppm.

The invention discloses a vacuum induction smelting method for nickel-based superalloy, comprising the steps of firstly, sequentially arranging raw materials from bottom to top in a crucible according to the order of Ni, Fe, C and Mo or Mo, Fe and Ni, melting and smelting; carrying out primary refining after completely melting the materials in a furnace and calming the surface of a melt; then, adding a strong nitride into the melt to form an element for secondary refining; and finally, adding a micro and easily-volatilized element, stirring until completely melting microalloy, and then, pouring to finish alloy smelting. The smelting method disclosed by the invention has an excellent denitrification effect; and compared with the existing method, the vacuum induction smelting method disclosed by the invention has the advantages that the nitrogen content of the nickel-based superalloy prepared by using the method is remarkably reduced, so that the application field of the nickel-based superalloy is greatly widened.

The invention relates to a process for treating coal chemical waste water, wherein a method combining active material adsorption and biochemical treatment is adopted. The method comprises the following steps of: firstly, introducing coal chemical waste water in a waste water regulating reservoir; secondly, introducing the waste water subjected to adsorption treatment by an adsorption tank into a clarification reservoir for sedimentation; then introducing the waste water subjected to the treatment of the clarification reservoir into a biochemical unit for biochemical treatment; and finally, introducing the waste water subjected to the biochemical treatment into a sedimentation reservoir for sedimentation treatment. In the technical scheme, macromolecular organic pollutants are removed through adsorption, therefore, the requirement of the subsequent biochemical treatment is met, and the problems of insufficient utilization of pores of activated carbon and incomplete exertion of the adsorbability of the activated carbon due to the influence of sludge when the activated carbon is added into an activated sludge aeration tank in the prior art are solved; and the process for treating coal chemical waste water has high efficiency and can sufficiently utilize the pores of the activated carbon and ensure the full exertion of the adsorbability of the activated carbon.

The present invention discloses one kind of coated low-nitrogen sand and its preparation process. The coated low-nitrogen sand consists of phenolic resin 1.5-4.0 wt% of the material, hexamethylene tetramine in 0-6 wt% of the phenolic resin, lubricant in 3-7 wt% of the phenolic resin, and raw sand for the rest. It has greatly lowered hexamethylene tetramine consumption, low nitrogen content and capacity of ensuring the surface quality of the casting. During its heated formation, the thermosetting phenolic resin can speed the curing, raise the hardening rate and raising the hot strength of the sand mold.

The invention discloses a method coke dry quenching by coal internal heat smouldering. In the method, high temperature carbonized coal gas produced by carbonized dry quenched coke is made into cool coal gas by washing and collecting tar; after the cool coal gas passes a circulating fan, part of the coal gas is introduced into a burner to be synthesized with high temperature waste gas into high temperature mixed gas satisfying the coal smouldering requirement; the high temperature mixed gas enters into a carbonization section of a coke oven to be used as a carbonization heat source; the other part of pure coal gas passing the circulating fan is introduced to a coke quenching and cooling section of a carbonization furnace by a booster fan to be used as an inertia medium of Ramsbottom coke and quenched coke; the cool coal gas passing the coke quenching and cooling section of the carbonization furnace absorbs the heat and then passes the carbonization section of the coke oven to carry out nonoxidation heating or weak-oxidation heating towards the coal together with the carbonization heat source to realize combustion-free circulation. The method simplifies the coke dry quenching technology, reduces the water content of the Ramsbottom coke, uses the heat of the Ramsbottom coke before coke quenching effectively, improves the utilization rate of the pure coal gas, reduces the use of combustion-supporting gas and accordingly reduces the energy consumption of the burner.

The invention relates to a delayed coking production method utilizing ethylene cracking tar as a raw material. A delayed coking mixed raw material is formed by the ethylene cracking tar, vacuum residue and catalytic oil slurry according to the weight proportion of 1:1-100:0-10; a defoaming agent which accounts for 10 to 100 ppm of feeding weight is injected into the top of a coking tower; the feeding rate of a delayed coking device is between 1 and 10 kg / h; the temperature of a preheating section is between 360 and 380 DEG C; the reaction pressure of the top of the coking tower is between 0.1 and 0.3 MPa (meter); the reaction temperature is between 490 and 510 DEG C; and the recycle ratio is between 0.15 and 0.55. The method extends the source and variety of raw materials of delayed coking, ensures that the sulfur content and the nitrogen content of gasoline and kerosene produced by the delayed coking device are reduced, the sulfur content and the metal content of wax oil and coke are reduced, the yield is not affected, the yield of the coke is increased, and any adverse effect on the process operation of the delayed coking device cannot be produced.

The invention relates to a method for producing a tire cord steel wire according to a converter billet continuous casting process and belongs to the technical field of production of tire cord steel wires in the field of ferrous metallurgy. The method comprises the following process steps: desulfurizing by pre-treating molten iron, namely desulfurizing by spraying magnesium on a foundry ladle; smelting by using a converter, namely deoxidizing and alloying, modifying steel ladle slag, re-carburizing the molten iron and adding low-alkalinity pre-melted slag into the steel ladle after tapping; adding ferro-silicon alloy, manganese iron alloy and micronitrogen carburant in the tapping process and re-carburizing; and in the refining process and after the refining is finished, rolling the wire at high speed by adopting a two-stage steel ladle bottom blowing argon system and adopting billet continuous casting of 130mm*130mm or 160mm*160mm. The method has the advantages that: the production isreduced; the production efficiency is improved; and the method is particularly suitable for development and production of tire cord steel products in steel enterprises without big billet or rectangular billet continuous casting and without vacuum treatment equipment.

The invention provides systems and methods for creating, managing and staging aerobic and / or anaerobic landfills. The invention provides systems and methods for collecting liquids from and recirculating liquids into landfills and systems and methods for collecting gases from and introducing gases into landfills. The invention also provides a novel conduit for conveying liquids and gases which comprises a first pipe coaxially disposed within a second pipe.