Produced water treatment vessels

Wastewater, which is a basic source of emissions, can be categorized in five ways (1) wastes containing a principal raw material or product (2) by-products produced during reactions, (3) spills, leaks, wash downs, vessel cleanouts, or point overflows, (4) cooling tower and boiler blowdown, steam condensate, water treatment wastes, and general washing water and (5) surface runoff. 

It can be stated that on average, nearly 100 million tons of raw steel are produced. The inhibitors used in 1998 amounted to 50 million, and inhibitors used in steel production are expected to increase only slightly (1-1.5%) in the future. Like most systems requiring inhibition, the water treatment piping and vessels in both cooling and boiler water systems are the most affected. 

Three types of waste streams are produced plasma offgas that is first treated to completely destroy VOCs and then cleaned by a two-stage scmbber, followed by a sophisticated filtration system prior to release wastewater from the water treatment system used in the purification of the off-gases and vitrified inorganic prodncts that fall to the bottom of the containment vessel. 

Oil and gas plants and gas industries use the same basic equipments (pumps, tanks, vessels columns etc.) because the basic physics and chemistry of hydrocarbon and gas processing is the same everywhere. Therefore the scenario types for various types of equipment might be categorized by risk analysis, accident history and operational experience. Accidents in oil and gas plants in one oil and gas operating company which includes six oil fields producing more than one million barrels of crude oil, 500 M ft gas, and 6500 barrels of liquified natural gas per day. Over a time period between 1985 to 2009 were assessed. This company has 7 operation units, 4 distillation plants, 10 gas compressor stations, 3 liquified gas plants, a gas refinery, and one water treatment plant. 

A hst of polyol producers is shown in Table 6. Each producer has a varied line of PPO and EOPO copolymers for polyurethane use. Polyols are usually produced in a semibatch mode in stainless steel autoclaves using basic catalysis. Autoclaves in use range from one gallon (3.785 L) size in research faciUties to 20,000 gallon (75.7 m ) commercial vessels. In semibatch operation, starter and catalyst are charged to the reactor and the water formed is removed under vacuum. Sometimes an intermediate is made and stored because a 30—100 dilution of starter with PO would require an extraordinary reactor to provide adequate stirring. PO and/or EO are added continuously until the desired OH No. is reached the reaction is stopped and the catalyst is removed. A uniform addition rate and temperature profile is required to keep unsaturation the same from batch to batch. The KOH catalyst can be removed by absorbent treatment (140), extraction into water (141), neutralization and/or crystallization of the salt (142—147), and ion exchange (148—150). 

This process, according to the manufacturer,54 has been developed in such a way that space requirements are kept to a minimum. A BIOPAQ IC reactor is used as the initial step in the treatment process. The name of this anaerobic reactor is derived from the gas-lift driven internal circulation that is generated within a tall, cylindrical vessel. These reactors have been operational in the paper industry since 1996. The second step in the purification process is a mechanically mixed and aerated tank. The aerating injectors can be cleaned in a simple way without the need to empty the aeration tank. Potential scaling materials are combined into removable fine particles. At the same time, the materials that may cause an odor nuisance are oxidized into odorless components. The process can be completed by a third and a fourth step. The third step focuses on suspended solids recovery and removal. The fourth step is an additional water-softening step with lamella separation and continuous sand filters in order to produce fresh water substitute. The benefits claimed by the manufacturer are as follows54 ... 

A jacketed polymerisation vessel had become coated internally by a build up of polymer residues, and the vessel was being cleaned by treatment with aqueous hydrogen peroxide. To 5000 1 of water in the vessel was added 150 kg of 27 wt% peroxide solution, and the vessel was heated by application of 10 bar steam (180°C) to the jacket. After a few minutes an explosion occurred, attributed to spontaneous ignition of a mixture of oxygen from the decomposing peroxide and monomer vapours produced by depolymerisation of the residue on the heated walls of the vessel. 

Gadolinium is produced from both its ores, monazite and bastnasite. After the initial steps of crushing and beneficiation, rare earths in the form of oxides are attacked by sulfuric or hydrochloric acid. Insoluble rare earth oxides are converted into soluble sulfates or chlorides. When produced from monazite sand, the mixture of sand and sulfuric acid is initially heated at 150°C in cast iron vessels. Exothermic reaction sustains the temperature at about 200 to 250°C. The reaction mixture is cooled and treated with cold water to dissolve rare earth sulfates. The solution is then treated with sodium pyrophosphate to precipitate thorium. Cerium is removed next. Treatment with caustic soda solution fohowed by air drying converts the metal to cerium(lV) hydroxide. Treatment with hydrochloric or nitric acid sol-... 

Equation (4.15) should be considered the final oil-treatment stage, in which a 0.5 to 1% water cut in treated oil is produced. Here a heater-treater-type horizontal vessel is more commonly used. A direct-fired burner-heater is normally placed in a front section of the horizontal treater. Controlling the system temperature for viscosity is important and may be mandatory for successful water dehydration. 

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