Distillation column waste

In die case of nylon-6,6 waste recycled by ammonolysis, nylon is treated with ammonia in die presence of a phosphate catalyst. Reaction occurs at 330°C and 7 MPa. Distillation of die reaction mixture produces ammonia which is recycled and three fractions containing (a) caprolactam, (b) HMDA and aminocaproni-trile, and (c) adiponitrile. Aminocapronitrile and adiponitrile are hydrogenated to yield pure HMDA, and die caprolactam is eidier converted to aminocapronitrile by further ammonolysis or distilled to produce pure caprolactam. The HMDA produced by this process is extremely pure (>99.8).1 The main impurities are aminomediylcyclopentylaniiiie and tetrahydroazepine, which are expected to be removed more effectively in the larger distillation columns employed in the larger plants. 

Devise a control system for the distillation column described in Chapter 11, Example 11.2. The flow to the column comes from a storage tank. The product, acetone, is sent to storage and the waste to an effluent pond. It is essential that the specifications on product and waste quality are met. 

Byproducts are materials that are not one of the intended products of a production process. An example is the sediment remaining at the bottom of a distillation column. Byproduct is a catch-all term and includes most wastes that are not spent materials or sludges. Listed byproducts are solid wastes when reclaimed used in a manner constituting disposal burned for energy recovery, used to produce a fuel, or contained in fuels or accumulated speculatively. On the other hand, characteristic byproducts are not solid wastes when reclaimed, unless they are used in a manner constituting disposal burned for energy recovery, used to produce a fuel, or contained in fuels or accumulated speculatively (Table 13.1). 

A distillation column is fed with a mixture of benzene and toluene, in which the mole fraction of benzene is 0.35. The column is to yield a product in which the mole fraction of benzene is 0.95, when working with a reflux ratio of 3.2, and the waste from the column is not to exceed 0.05 mole fraction of benzene. If the plate efficiency is 60 per cent, estimate the number of plates required and the position of the feed point. The relation between the mole fraction of benzene in liquid and in vapour is given by ... 

The equilibrium is rapidly established, at high temperature, between Na, K, NaCl and KC1. The equilibrium shifts to the products when K is continuously removed by distillation through a packed column. During operation, KC1 is melted and introduced through a trap to the column. Molten Na is fed to the bottom of the column (the lower portion of which acts as a reactor whereas the upper portion is a fractionator). K vapour is fractionated and condensed in an air-cooled condenser, with the reflux pumped back to the column. Waste NaCl is continuously removed from the bottom of the column. 

The countercurrent (recycle) cascade (Fig. 8.3) is much more useful because by reprocessing the waste stream a larger fraction of the desired isotope is recovered. In a recycle cascade the i th stage is fed by a mixture of the product, Y( i) from the (i — l) th, and the waste, X(i+ X) from the (i + l) th, stage. A distillation column... 

The building will also contain absorption columns for the pretreatment of waste gases as well as distillation columns for solvent recovery. A generous... 

Significantly endothermic AHf (1) 147 kJ/mole 2.8 kJ/g. The monomer is sensitive to light, and even when inhibited (with aqueous ammonia) it will polymerise exother-mally at above 200°C [1]. It must never be stored uninhibited, or adjacent to acids or bases [2]. Polymerisation of the monomer in a sealed tube in an oil bath at 110°C led to a violent explosion. It was calculated that the critical condition for runaway thermal explosion was exceeded by a factor of 15 [3]. Runaway polymerisation in a distillation column led to an explosion and fire [4]. Another loss of containment and fire resulted from acrylonitrile polymerisation in a waste solvent tank also containing toluene and peroxides (peroxides are polymerisation initiators) [5]. Use of the nitrile as a reagent in synthesis can lead to condensation of its vapour in unseen parts of the equipment, such as vent-pipes and valves, which may then be obstructed or blocked by polymer [6]. 

The large scale distillation column shown in Figure 1 is part of an extractive distillation plant employed in the waste water refinement process at HOECHST AG, Frankfurt/Main. 

Steam stripping. A steam-stripping process is carried out in a distillation column, which may be either a packed or tray tower. Steam is introduced from the bottom and waste flows downward. The obtained stream, which is rich in volatile components, is further treated to remove the volatile materials. Air stripping may also be required to remove the volatile materials. 

Needless to say, if there is no interest in recovering and selling MF, the emphasis being on merely purifying the FU, then obviously the secondary distillation column 7 of the plant shown can be omitted, but this incurs a furfural loss of 1.5 percent of the feed and causes an uncomfortable waste stream to be disposed of... 

The waste water of all furfural plants contains some carboxylic acids, with acetic acid being the principal load, ranging from 1 to 5 percent by weight, as well as some furfural, in concentrations up to 600 ppm. The furfural concentration depends on the quality of the first distillation column, with good columns going down to 50 ppm. 

Plinke process In this process sulfuric acid is distilled at atmospheric pressure with indirect heating by natural gas and oil combustion (combustion chamber temperature 800 to 1100°C). This process is predominantly used in Europe. The to be concentrated waste acid is fed in at the top of the distillation column into boiling 96% sulfuric acid at atmospheric pressure and 320°C in a cast iron boiler. Water is expelled at the column head leaving a 96% acid. By adding nitric acid, which is mainly reduced to nitrogen, organic impurities can be removed oxidatively. 

A novice manufacturer of alcohol for gasohol is having a bit of difficulty with a distillation column. The operation is shown in Fig. E2.11, Too much alcohol is lost in the bottoms (waste). Calculate the composition of the bottoms and the weight of alcohol lost in the bottoms. 

A typical distillation column is shown in Fig. E2.14 together with the known information for each stream. Calculate the kilograms of distillate per kilogram of feed and per kilogram of waste. 

In the case in which a water-miscible solvent is used, such as ethanol, methanol, or acetone, fractional distillation equipment will be required. This type of equipment also separates any dissolved solids in the wastes, such as those generated when water washing the marc. One potential problem with significant dissolved solids in the distillation feed is that these solids can precipitate out in the distillation equipment as the organic solvent is removed, potentially plugging the distillation column. The... 

Almost half the amount of pyrolysis gas produced was burnt in the exhaust gas flare the other part was sufficient to support the energy demands of the process, being burnt in the radiation fire tubes. Waste heat from the reactor heating (cooler) was sufficient to heat the distillation column. 

---