A process for synthesis of urea from CO.sub.2 and NH.sub.3 wherein a steam flow (13) produced in the condenser (3) of a high-pressure synthesis loop is compressed to raise its pressure and temperature before using the steam as a heat source for a downstream step of the process.

The present invention relates to a xylitol preparation device integrating evaporation, crystallization and centrifugation, including a xylitol tank, a cleaning liquid tank, a recycling tank and a multiple distribution system, wherein the multiple distribution system includes J groups of evaporators for evaporation concentration, K groups of vacuum crystallization kettles for vacuum crystallization and L groups of centrifuges for centrifugation, wherein 2≤J≤6, 6≤K≤12 and 2≤L≤4; the evaporator, the vacuum crystallization kettle and the centrifuge in different groups are sequentially connected in series with one another through a pipeline and a valve respectively; by controlling on and off of each valve, a xylitol exchange liquid is switched and controlled between a series-connection mode and a parallel-connection mode in the multiple distribution system to enable evaporation, crystallization and separation processes to reach an optimal effect distribution so as to improve productivity. The present invention further discloses a control method of the device. The processes and equipment of the present invention are highly integrated to realize continuous integrated production of xylitol preparation with low energy consumption and high automation degree, and full utilization of raw materials.

A MEG reclamation process includes the step of increasing above 2,000 ppm the divalent metal salts concentration of a rich (wet) MEG feed stream flowing into a precipitator. The increasing step includes routing a salts-saturated MEG slipstream from the flash separator it to the precipitator. The slipstream may be mixed with a fresh water feed stream, a portion of the rich MEG feed stream, or some combination of the two. The rich MEG feed stream also may be split into two streams, with a portion of the stream being heated and routed to the flash separator and the other portion being combined as above with the removed slipstream. The process can be performed on the slipstream after dilution and prior to entering the precipitator or after being loaded into the precipitator. Removal of the insoluble salts may be done in either a batch or continuous mode.

A process for manufacturing a purified aromatic carboxylic acid is provided. The process comprises purifying a crude aromatic carboxylic acid in a purification zone to form a purified aromatic carboxylic acid; crystallizing a purified aromatic carboxylic acid in a crystallization zone to form a solid/liquid mixture comprising purified aromatic carboxylic acid solids; filtering the solid/liquid mixture through a filter member of a rotary pressure filter apparatus to form a filter cake comprising the purified aromatic carboxylic acid solids; removing the filter cake from the filter member; rinsing the filter member to produce a filter rinse product, wherein the filter rinse product comprises purified aromatic carboxylic acid; and directing at least a portion of the filter rinse product downstream of the purification zone for recycle to the rotary pressure filter apparatus.

There is a process for the selective recovery of transition metals from an organic stream containing transition metals. The organic stream and possibly a first extractor if solid, are melted up to the liquid state. The extractor consists of an ionic liquid or a mixture of two or more ionic liquids and the ionic liquid contains an ammonium salt as cation and as anion an anion with chelating properties. A melted organic stream and a first extractor, optionally melted, are fed to a first liquid-liquid extraction unit working at a temperature of at least 150° C. where the liquid-liquid extraction is carried out obtaining a liquid mixture containing an ionic liquid, or a mixture of two or more ionic liquids, and metals. After extraction, the liquid mixture is cooled at a temperature between 0° C. and 70° C. and becomes biphasic; then the cooled mixture is sent to a first separation unit, to separate a liquid phase that contains ionic liquids and metals, and a metal-depleted solid phase. After the first separation, the separated metal-depleted solid phase is optionally sent to a washing unit to which a solvent is fed, so as to eliminate the residual ionic liquid by transferring it into the solvent and obtaining a metal-depleted solid phase. Then the separate liquid phase containing ionic liquids and metals is sent into a liquid-liquid precipitation and separation unit, adding a counter-solvent, thereby obtaining a solid phase containing the metals and a liquid stream containing counter-solvent and ionic liquids.

A method of making a cobalt compound for feed supplements includes the steps of dissolving cobalt acetate tetrahydrate in water to form a mixture, adding an acid to the mixture, sonicating the mixture for a selected time, removing acetic acid from the mixture, and separating crystals of the cobalt compound from the mixture.

The invention is a high-salt waste water air powered low temperature evaporating device and method of use. A tray is mounted on a lifting platform; an air inlet and a water inlet are on the tray. Air distributing pipes are arranged at the center of the nested column tubes (33). A groove (4) is installed at the top of the tray, and mounting points are accompanied by multiple nested column tubes (33). The nested column tubes (33) are connected with the air inlet. An atomizer is arranged inside the air distributing pipes; and the atomizer is connected with the water distributing pipes. Using air power evaporates concentrated waste water multiple times so that the salt in the wastewater reaches saturated concentration, and therefore, the wastewater temperature is reduced, salt is crystallized and separated out, liquid is continuously evaporated, and the wastewater can be completely treated.

A method for the recovery paraxylene with reduced crystallization. Paraxylene is recovered from a mixture of C8 aromatic hydrocarbons in a pressure swing adsorption zone and a crystallization zone. The invention provides for lower throughput through the crystallization zone, resulting in lower capital costs, reduced electricity in operating separation equipment, as well as reduced refrigeration duty.

A method for recovering paraxylene from a mixture of aromatic hydrocarbons. The process uses a pressure swing adsorption zone followed by a paraxylene recovery zone. The invention provides for lower throughput through the paraxylene recovery zone, resulting in lower capital costs and operating costs.

Formation of low-crystallinity phytosterol nanoparticles via cooling-controlled supercritical carbon dioxide (SC—CO.sub.2) impregnation of phytosterols into biodegradable nanoporous starch aerogels and methods of preparing these aerogels are disclosed. The nanoporous starch aerogels increase water dissolution and bioaccessibility of the phytosterols, thereby making them available for preparation of high nutraceutical value foods.