1AO Process descriptionWork solution (WS) is pumped into filters to remove solid impurity, and then is preheated (or cooled) by going through heat exchanger and preheater. Hydrogen, which comes from chlor-alkali plant, is purified by filter, and then gets into hydrogenator with WS at the same time.The hydrogenator is consisted of three palladium catalyst beds, and each section has gas and liquid distributer. The distributer can make the gas and liquid those get into the towerwell-distributed. Any section of the three beds can be used alone or two sections in series and three parts at the same time (in series) if necessary, which bases on the need of process and hydrogenate efficiency and activity of palladium catalyst. When two sections of the hydrogenater are used in series, the WS and hydrogen first get into the top of upper section, and then go through the palladium bed in concurrent downwards. After that, both the two flow out from the bottom of the upper section and then get into the top of down section by pipe outside the tower. The WS and hydrogen (not reacted) flow out from the bottom of the down section and then go into hydrogenater degasser.Hydrogenated WS (HWS) and the not reacted hydrogen, which together come out from the hydrogenator, go into hydrogenator degasser. The gas flows out from the top, and then gets into condenser. Condensate goes into receiver tank, and off gas is exhausted after controlling the flow by flow meter.Determined level of the degasser is controlled by auto valve. 10% HWS2first gets into alumina bed, and then together with other 90% HWS go through filters to remove solid impurity. After that, HWS going through heat exchanger and then gets into tank.Little hydrogen or other gases, which dissolve in the HWS, resolve in the tank. The gases then go into condenser, and are exhausted by evacuation water seal and flame arrester.Part of the hydrogenated WS, which flows out from the hydrogenator degasser, is pumped back into the hydrogenator. This can make the temperature of the tower well-distributed, and hydrogenated efficiency steady and operation safe. Hydrogenated WS (HWS) and phosphoric acid are pumped into HWS cooler, in which the temperature of HWS is cooled downto 50～55℃, and then both get into upper part of oxidizer. The HWS is stored in HWS tank, and the phosphoric acid is storedin phosphoric acid mixing tank. Phosphoric acid is pumped bymetering pump.There are three hollow sections of the oxidizer and the air is introduced into the tower from the bottom of middle and lower sections separately. The air is distributed into small bubble by gas distributor. Air flow based on oxidized efficiency and the concentration of oxygen in the off gas (normally is 6%-9%). Parts of or all the air, which is introduced into the middle and lower sections, flow into the bottom of the upper part of the oxidizer. The HWS and the air, which get into the bottom of the upper part, are concurrent upwards. HWS is partly oxidized and flows out from the top of the upper section and then gets into the bottom of the middle section. The HWS together with the fresh air are3concurrent upwards. The mixture of air and liquid, which flows out from the top of the upper section, gets into degasser to eliminate air. After that, the liquid gets into the bottom of the lower part and together with the fresh air are concurrent upwards. The mixture of air and liquid, which flows out from the top of the middle section, gets into degasser to eliminate air. Determinate level of the degasser is controlled by auto valve. Oxidized WS (OWS), after cooled by cooler, gets into tank, and then is pumped into the bottom of extractor. Off gas of theoxidizer gets into condenser, and then gas and condensate get into aromatic receiver drum. After that, the gas goes into off gas separator. Liquid is recovered into aromatic recover tank, and the off gas gets into handling unit after the pressure of the top of the tower is controlled by instrument. The temperature of the oxidizer is controlled by controlling flow of cooling water into U type pipe which is contained inside the tower.The oxidized WS, which contains H2O2, gets into the extractor from the bottom of the tower. It is dispersed by sieve plate and then floats upwards. Meanwhile, DMW with phosphoric acid is pumped to the top of the extractor from DMW mixing tank. The flow of the water is controlled by auto valve. The water flows downwards by downcome of the sieve plate, and the oxidized WS and water are countercurrent extraction.In this process, the water works as continuous phase and the oxidized WS as disperse phase. The concentration of H2O2 in DMW is getting higher as the water flows downwards and at last the water flows out from the bottom of the extractor (now the water is called extract). The extract gets into the top of4purification tower by potential difference. The concentration of H2O2 in the oxidized WS is getting lower as it floats upwards. Atlast, it flows out from the top of the extractor (now it is called raffinate).Purification column contains fillings and heavy aromatic. The extract, which gets into the purification column from the top of the column, is dispersed in the tower and flows downward. At the same time, heavy aromatic gets into the bottom of the purification column from the overhead aromatic tank by potential difference. The aromatic and the extract are countercurrent contact to eliminate organic impurity in H2O2. In this process, the heavy aromatic works as continuous phase while the extract as disperse phase. The H2O2, after purification, flows out from the bottom of the purification column and goes into crude H2O2 separator to eliminate aromatic that may be carried by H2O2. After that, the H2O2 goes into metering tank, in which it is blowed by air. And then, the H2O2 is pumped to packing or concentration procedure.The heavy aromatic, which flows out from the top of the purification column,enters into aromatic recovery tank. Attention, for safety consideration, before the aromatic is used for distillation or mixing of WS, it must be washed by DMW to eliminate H2O2 (the concentration of H2O2 must be below 0.15g/L). Raffinateflows out from the top of the extractor, and then goes into raffinate separator to eliminate water. After that, it goes through WS metering tank and then gets into the bottom of alkaline tower. The alkaline tower contains fillings and potassium carbonate solution (40% approximately) goes into the alkaline5tower form the top of the tower. In the alkaline tower, the H2O2 in the WS decomposes, and acid in the WS was neutralized. Besides, the water in the WS can also be further eliminated.The WS, which flows out from the top of the alkaline tower, goes into alkalisettler and then into alkali separator to eliminate potassium carbonate solution. After that, the WS enters into alumina bed which contains activated alumina. The alumina is used to recover anthraquinone degradation. And the potassium carbonate solution can also be absorbed by the alumina. The WS flows out from the top of the alumina bed and gets into WS tank. The WS is then pumped into hydrogenator and another circulation is started.2011-3-10。