Effluent coolers

Syngas Effluent Cooler (SEC), in which high-pressure steam is generated from the hot syngas leaving the reactor... 

From the reactor, the effluent flows through a separator (for the separation of inorganic salts precipitated during the process), a heat exchanger (with the influent), a heat recovery unit, an effluent cooler, and a letdown system to return the effluent to the ambient pressure. Then, a liquid/gas separator sep-... 

Reprinted with permission from "Corrosion by Sulfide Containing Condensate in Hydrocracker Effluent Coolers, API Division of Refining, May 1968, American Petroleum Institute, Washington, D.C.)... 

Fig. 2 Continuous polymerization apparatus A, CO2 cylinder B, monomer C, initiator solution D, continuous syringe pumps E, syringe pumps FI, steady-state filter G, thermo-stated autoclave H, static mixer I, chiller/heater unit J, effluent cooler K, gas chromatograph VI, V2, four-way valves V4, three-way valves V5, V6, two-way valves V7, heated control valve [51]... 

The Parsons/Honeywell EDS also included tests of CATOX units to ascertain if residual mustard agent that might have survived steam treatment in the MPTs and CST had been destroyed (Parsons, 2000a). These units were challenged with 10 mg/m of mustard agent, compared with expected values of less than 3 J,g/m in a full-scale operation. The test results showed that the CATOX units could successfully achieve a destruction and removal efficiency of 99.999 percent at this level for a period of 637 hours. No catalyst deactivation or increased pressure drop was observed. However, there was some plugging of the effluent cooler, presumably by products of combustion of the mustard agent. 

Accommodating the heat of reaction requires equipment and costs. For example, exothermic reactions are often controlled by water cooling loops that withdraw the heat of reaction by boiling water at the wall of the reactor or in the effluent cooler. 

Operators report frequent problems with E-102, which are to be investigated. The PFD for the plant s 100 area is reviewed, and E-102 is identified as the Reactor Effluent Cooler. The process stream entering the cooler is a mixture of condensable and noncondensable gases at 654°C that are partially condensed to form a two-phase mixture. The coolant is water at 30°C. These conditions characterize a complex heat transfer problem In addition, operators have noticed that the pressure drop across E-102... 

I throttled back on the cooling water flow to dozens of exchangers. Several of these water coolers had not been used for years, but no one had bothered to block-in the water flow. Liz and I spent most of an afternoon on this activity. Based on the combined water temperature returning to the cooling tower (see Fig. 32.3), 1 had reduced the total circulating water flow by 20 percent. But the water flow to the hydrotreater effluent cooler had not increased at all. 

Accelerated corrosion due to mixed vapor/liquid streams is found primarily in crude and vacuum furnace headers and in transfer lines of crude distillation units, in overhead vapor fines and condenser inlets on various fractionation towers, and in reactor effluent coolers of hydrocracking and... 

Air-cooled reactor effluent coolers of hydrocracking and hydrotreating units are also prone to impingement-type corrosion. Poor flow distribution through large banks of parallel air coolers can result in excessive flow velocities in some coolers, usually those in the center. The resulting low flow velocities in the outer coolers can canse deposition of ammonium sulfide and/or chloride in these coolers this blocks the tubes and further increases velocities in the remaining air coolers. 

If necessary, first-stage reactor effluent maybe further cooled to 200—250°C by an iaterstage cooler to prevent homogeneous and unselective oxidation of acroleia taking place in the pipes leading to the second-stage reactor (56,59). 

After the SO converter has stabilized, the 6—7% SO gas stream can be further diluted with dry air, I, to provide the SO reaction gas at a prescribed concentration, ca 4 vol % for LAB sulfonation and ca 2.5% for alcohol ethoxylate sulfation. The molten sulfur is accurately measured and controlled by mass flow meters. The organic feedstock is also accurately controlled by mass flow meters and a variable speed-driven gear pump. The high velocity SO reaction gas and organic feedstock are introduced into the top of the sulfonation reactor,, in cocurrent downward flow where the reaction product and gas are separated in a cyclone separator, K, then pumped to a cooler, L, and circulated back into a quench cooling reservoir at the base of the reactor, unique to Chemithon concentric reactor systems. The gas stream from the cyclone separator, M, is sent to an electrostatic precipitator (ESP), N, which removes entrained acidic organics, and then sent to the packed tower, H, where SO2 and any SO traces are adsorbed in a dilute NaOH solution and finally vented, O. Even a 99% conversion of SO2 to SO contributes ca 500 ppm SO2 to the effluent gas. 

For coolers, condensers, steam heaters and reboilers. The effluent cooling water and condensate are typically discharged as follows ... 

A typical emergency scrubber system consists of a scrubbing column (often filled with packing), recirculating liquid pumps, solvent cooler, and in some cases (where the entering effluent gas/vapor is at a low pressure) exhaust blowers (see Fig. 23-57). Redundant equipment and instrumentation is usually provided to ensure reliable scrubber operation at all times. 

The effluent gas from the reactor contains about 50% maleic acid (not maleic anhydride). The balance is some. unreacted feed, CO2, water, and some miscellaneous waste products. A recycle stream is passed through a cooler and recharged to the reactor. The purpose is not only to take another pass at the feed but also to dilute the feed with some already-made maleic acid. That helps to disperse the heat of reaction and to control the operating conditions. 

The bulk of the effluent is run through a cooler (heat exchanger) and a condenser to remove the light ends that include traces of carbon monoxide and carbon dioxide and by-product water. The bottom stream is maleic acid, which is easily dehydrated, as in Figure 20—4, by vacuum distillation or azeotropic distillation with ortho-xylene. See Chapter 3 if youVe forgotten totally everything about azeotropic distillation.) The dehydrated maleic acid is maleic anhydride. Further purification is done by distillation.,... 

Air streams from the digestion system, vacuum cooler, concentrator, and other areas where fluorine is evolved are connected to a highly efficient absorption system, providing extremely high volumes of water relative to the stream. The effluent from this absorption system forms part of the recycled water and is eventually discharged as part of the product used for fertilizer manufacture. The Minnesota plant requires a constant recirculating water load in excess of 3000 gpm (11.4 m /min), but multiple use and recycle reduce makeup requirements to less than 400 gpm (1.5 m /min) or a mere 13% of total water use. 

When most of the sample had passed through the column and the liquid level was at the top of the resin, the reservoir was washed with 25 mL of water, which was drained through the column. The effluent water was preserved and stored in a cooler for future extraction. 

Water sprays should be used only as a stopgap measure, because of the swell they cause in the plant s effluent volume, and also their tendency to create a safety hazard in the vicinity of the cooler. 

From the reactor, the effluent is cooled in E-101, cooled further to 110°F in water cooler E-102, and then enters diphenyl ether decanter V-102. The lighter DPE phase is returned with pump P-104 to the emulsifier. The other phase is pumped with P-105 to another stirred vessel R-102 called a Springer to which 5% HC1 also is pumped, with P-106 here reaction 2 occurs. 

Tile partially purilied synthesis gas leaves the C02 absorber containing approximately 0.1% CO2 and 0.5% CO. This gas is preheated at the methanator inlet by heat exchange with the synthesis-gas compressor interstage cooler and the primary-shift converter effluent and reacted over a nickel oxide catalyst bed in the methanator. The methanation reactions are highly exothermic and are equilibrium favored by low temperatures and high pressures. 

FIGURE 1 Typical temperature profiles for several process heat exchanger applications (a) product cooler (b) feed heater with condensing stream (c) multicomponent feed heater with vaporization and superheating (d) pure-component product condenser (e) multicomponent product condenser (f) typical feed-effluent heat exchanger. 

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