Steam sour water

Numerous other multistaged configurations are possible. One important variation of a stripper, shown in Fig. 13-7r is a refluxed stripper, in which an overhead condenser is added. Such a configuration is sometimes used to steam-strip sour water containing NH3, H2O, phenol, and HCN. 

Steam strip spent doctor solution to hydrocarbon recovery before air regeneration replace treating unit with other, less objectionable units (Merox) Use sour water oxidizers and gas incineration ... 

The catalyst dust is then separated from the resulting carbon dioxide stream via cyclones and/or electrostatic precipitators and is sent off-site for disposal or treatment. Generated wastewater is typically sour water from the fractionator containing some oil and phenols. Wastewater containing metal impurities from the feed oil can also be generated from the steam used to purge and regenerate catalysts. 

Certain refinery wastewater streams are treated separately, prior to the wastewater treatment plant, to remove contaminants that would not easily be treated after mixing with other wastewater. One such waste stream is the sour water drained from distillation reflux drums. Sour water contains dissolved hydrogen sulfide and other organic sulfur compounds and ammonia which are stripped in a tower with gas or steam before being discharged to the wastewater treatment plant. 

Aqueous plant effluent and drawoff streams such as steam condensate, sour water, or spent caustic soda solution may require disposal to a disengaging drum. 

If HjS is continuously present in the flare gas or if the flare seal drum also functions as a sour water disengaging drum, then the effluent seal water must be routed to a sour water stripper, desalter, or other safe means of disposal. Withdrawal from the drum is by pump in place of the normal loop seal arrangement. Two pumps are provided one motor driven for normal use, and the other having a steam turbine drive with low pressure cut-in. The seal drum level is controlled by LIC with high and low alarm lights plus an independent high level alarm. 

Operating variables Reduced stripping steam or atomizing steam higher preheat or riser temperature. Restore the steam flows this is not the right place to solve a sour water problem. 

As an introduction to the technical aspects of the conference, the results of some studies conducted by the writer on two relevant subjects are presented below. The first commentary is concerned with the design of sour-water strippers and the effects of thermodynamic data on these designs the second commentary is concerned with the calculation of enthalpies of steam-containing mixtures, essential to the design of coal processing and related plants. 

Many refineries now use vacuum pumps and surface condensers in place of barometric condensers to eliminate generation of the wastewater stream and reduce energy consumption. Reboiled side-stripping towers rather than open steam stripping can also be utilized on the atmospheric tower to reduce the quantity of sour-water condensate. 

Many processes in a refinery use steam as a stripping medium in distillation and as a diluent to reduce the hydrocarbon partial pressure in catalytic or thermal cracking [37]. The steam is eventually condensed as a liquid effluent commonly referred to as sour or foul water. The two most prevalent pollutants found in sour water are H2S and NH3 resulting from the destmction of organic sulfur and nitrogen compounds during desulfurization, denitrification, and hydrotreating. Phenols and cyanides also may be present in sour water. 

The purpose of sour water pretreatment is to remove sulfides (H2S, ammonium sulfide, and polysulfides) before the waste enters the sewer. The sour water can be treated by stripping with steam or flue gas, air oxidation to convert sulfides to thiosulfates, or vaporization and incineration. 

The petroleum industry uses them mostly as roughing devices to reduce the loading on activated sludge systems. In some cases, trickling filters are used to pretreat steam-stripped sour water before mixing it with other refinery wastewater streams for secondary treatment [48]. 

The stripping steam rate should be adjusted to maximize stripping that is, minimize hydrocarbon carry-under to the regenerator. In practice, the stripping steam rate should be increased until there is no visible decrease in regenerator temperatures, and cyclone loadings and sour water handling capability are not exceeded. 

Figure 10.3 shows a simple sour-water stripper. The steam is used to remove NH3 and H2S, dissolved in the waste, or sour water. In the diesel oil stripper discussed above, all the stripping steam went out the top of the stripper. But what happens to the stripping steam in a water stripper It is used in four ways ... 

Steam st ripping — This technique has long been used on sour water and process condensate in refineries. Steam stripping is also becoming more attractive in other industries as the demand for water conservation increases. In a number of process plants, high-quality process condensates are recovered, stripped, and reused. Effluent oil concentrations of less than 50 ppm are achievable in stripping columns but actual concentration depends on influent concentration, tower design and contaminant type. 

The Blue Ribbon Sour Mash Company plans to make commercial alcohol by a process shown in Fig. P5.25. Grain mash is fed through a heat exchanger where it is heated to 170°F. The alcohol is removed as 60% by weight alcohol from the first fractionating column the bottoms contain no alcohol. The 60% alcohol is further fractionated to 95% alcohol and essentially pure water in the second column. Both stills operate at a 3 1 reflux ratio and heat is supplied to the bottom of the columns by steam. Condenser water is obtainable at 80 F. The operating data and physical properties of the streams have been accumulated and are listed for convenience ... 

B. Liu, Q. Zong, P. P. Edwards, F. Zou, X. Du, Z. Jiang, T. Xiao, H. AlMegren, Effect of titania addition on the performance of C0M0/AI2O3 sour water gas shift catalysts under lean steam to gas ratio conditions, Ind. Eng. Chem. Res. 51 (2012) 11674-11680. 

For stripping ammonia from sour water stripping steam 1 kg/kg feed. 35 theoretical trays. 

Solvent or stripped liquid concentration > design boilup rate or steam stripping rate too low/feed concentration > expected/feed contamination for sour water stripper acid in feed may be chemically bonded with NH3 and prevent adequate stripping of NH3/[foaming] /leak in preheater exchanger/[column malfunction]. ... 

Pluggng of overhead system top temperature not within the operating window for sour water strippers temperature < 82 °C at which ammonium polysulfides form but temperatures too high give excessive water in overhead vapor causing problems for downstream operation/overhead lines not insulated/insuflicient steam tracing on overhead vapor lines. 

Instrument error] calibration fault/sensor broken/sensor location faulty/sensor corroded/plugged instrument taps for sour water strippers water or steam purge of taps malfunctioning or local temperatures < 82 °C at which ammonium... 

The sour water (condensates from various fractionation units) containing sulfides and ammonia is generally steam or air-stripped before being discharged to the sewer lines. Depending on the pH of the sour water, the stripping can reduce the sulfide and ammonia concentrations in the final effluent. 

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