Chemical feed

Most cleaners are available for < 2.20/kg either as a dry blend or as aHquid. Liquid cleaners are usually less expensive than the dry blend type. A trend toward Hquid cleaners is evident as of this writing (ca 1994) because of convenience features such as automatic additions of the cleaner by chemical feed pump. Safety features such as minimized heat generation upon blending with water to make the desired concentration are also important. 

Transportation of Chemicals. Feed materials and finished products are frequendy transported by tank tmck and railroad tank cars. Design, constmction, and movement of these vehicles is regulated by the U.S. Department of Transportation (DOT) (97). The DOT regulations require placarding of material-transport vehicles to alert the pubHc and emergency personnel to the nature of their contents. 

Sanitizers. Spa and hot-tub sanitation is dominated by chlorine- and bromine-based disinfectants. Public spas and tubs usually employ automatic feeders, eg, CI2 gas feeders, to maintain a disinfectant residual. Private or residential spas and tubs can use automatic chemical feeding or generating devices, or they can be sanitized manually with granular or liquid products. The most widely used products for private spa and tub sanitation are sodium dichloroisocyanurate and bromochlorodimethylhydantoin. Granular products are normally added before and after use, whereas solids, eg, stick-bromine, are placed in skimmers or feeders. Bromine generating systems can also be used and are based on oxidation of bromide ions (added to the water as sodium bromide) by peroxymonosulfate, chloroisocyanurates, hypochlorites, or ozone to generate the disinfectant HOBr. 

The mechanistic steps are as follows paraffins dehydrogenate to olefins the olefins oligomerize and cyclize and the cycHcs aromatize. Because the first step is rate controlling, very Httie olefin is actually present. The BTX product is relatively free of nonaromatics and therefore is very desirable as a chemical feed. As in reforming, some C —C2 fuel gas is produced along with a valuable hydrogen stream. Prom a C —feed the BTX product is roughly 35 45 20, respectively. 

Regularly (at least annually) review all chemical feed and handling equipment. 

There is a wide range of conversion levels. The term maximum conversion type has no precise definition but is often used to describe a level of conversion, where there is no net fuel oil manufactured. A fuel products refinery with specialities may manufacture lubricating oils, asphalts, greases, solvents, waxes and chemical feed stocks in addition to the primary fuel products. The number and diversity of products will naturally vary from one refinery to another. Refineries produce chemical feed stocks for sale to the chemical affiliates and do not have responsibility for the manufacture of chemical products directly. Both operations may be carried out at the same physical location but the corporate product responsibilities are usually separate. 

Corrective Action Check pump and meter settings. Conflrm thast setting correspond with anticipated chemical feed rates. 

Refineries produce chemical feed stocks for sale to the chemical affiliates and do not have responsibility for the manufacture of chemical products directly. Both operations may be carried out at the same physical location but the corporate product responsibilities are usually separate. 

Because of their compact size, packaged vertical boilers can be custom-designed as a complete boiler plant system and simply shipped to the customer on a steel skid or platform. This type of system may comprise a dual boiler arrangement, with a pretreatment unit (water-softening and chemical-feed system), boiler blowdown and condensate return facilities, and also possibly a dual stack containing an economizer. This type of packaged system may reach 85% GCV efficiency. 

Pressure vessels and appurtenances should be constructed of stainless steel or other corrosion-resistant materials. Ideally, these steam generators should receive hot demineralized FW to minimize chemical treatment requirements. Alternatively, where a main boiler plant is installed, 100% steam condensate provides a good source of FW. In practice, it is very difficult to accurately control the correct amount of chemical feed. Chemicals are typically restricted to potable grade, deposit control agents such as polyacrylates, and other materials listed under the Code of Federal Regulations, CFR 21 173.310, or National Sanitary Foundation (NSF International) approval system. These boilers may be electrically heated or gas-fired. 

As part of the overall boiler plant operational management process, various items of water treatment equipment must be periodically checked, tested, back-washed, regenerated, or otherwise maintained. Such equipment may include filters, ion-exchange softeners and demineralizers, the RO plant, chemical feed tanks, and condensate polishers. 

Traditionally, boiler house operational duties include the monitoring of day tank chemical treatment levels and the top-up of additional chemicals as required. Also required is the checking of consumable inventory stock levels and the inspection of chemical feed pumps, injection points, automatic controllers, and other items of dosing and control equipment. 

Arrangements for chemical feed and control also were limited. In these boilers, 1/2 inch to perhaps 1 inch (12.5-25 mm) of multilayered scale could easily deposit during the period between waterside inspections. It was often assumed that these operating conditions were the norm, that regular acid cleaning was a way of life, and that nothing better could be expected. 

Deposition can be minimized by a combination of good operating practice and overall program management, together with the use of appropriate external conditioning equipment, internal chemical treatments, and proper chemical feed and control methods. 

Generally, chemical feed arrangements and TDS controls are more sophisticated than in LTHW systems and some form of pretreatment is almost always provided. 

The chemical feed pump should be wired into the boiler FW pump, so that when the boiler calls for water, both phosphate and alkali are added in proportion to the FW volume and the hardness it contains. 

Also, because of the speed of reaction, the chemical feed solution should be protected against reaction with atmospheric oxygen. 

Simplicity of chemical feed system and chemical addition... 

Inspect chemical feed and control system, adjust as necessary... 

Thus, programs based on multiblends are relatively expensive to use compared with programs based on the use of separate products that are matched to the potential for particular problems identified in a boiler plant. Nevertheless, they remain commonplace for the smallest boiler houses, but as the organizational size of the customer and its volume of daily steam production increases, so the trend for individual chemical treatments on the site tends to predominate. Often, more sophisticated chemical feed and control arrangements are also employed. 

Traditionally, a common solution to the problem of matching relatively higher levels of technical support with lower chemical volumes for these smaller customers has been via a one- to three-year, fully inclusive product and services contract. Such a contract will specify the frequency of service visits to be made to the customer s site and the type of work to be carried out. It will also, perhaps, limit the maximum volumes of chemical treatments to be supplied during the contract lifetime, or perhaps designate the amount of chemicals required based on treating a certain annual volume of boiler FW. Contracts may include for the provision of chemical feed and control equipment and for the supply of labor for boiler cleaning, chemical addition, and drum removal services (drumless delivery). Product and services contract prices may some-... 

STABREX is easier and simpler to use compared to any other oxidant available for industrial water treatment. The product is pumped directly from returnable transporters (PortaFeed Systems)17 with standard chemical feed equipment. Previously, the only practical ways to apply bromine were to oxidize bromide solutions on-site with chlorine in dual liquid feed systems, or with one of the solid organically-stabilized bromine products applied from sidestream erosion feeders. The former is cumbersome and complex, and the latter is prone to dusting and difficult to control. Other oxidants require complex handling and feed of toxic volatile gases, unstable liquids, multiple-component products, or reactive solids. Simplicity in use results in reduced risk to workers and to the environment. 

System component A small mixing tank, two chemical feed tanks, a mixer, and a large tank equipped with an oil skimmer and a sludge pump. The mixing tank has a retention time of 15 min and the oil skimming tank has a retention time of 2.5 h. 

Contaminants can be any chemical substance used in the plant that does not belong in the reaction system. This includes coolants, air (oxygen), solvents, lubricants, rust, and so forth. Changes in chemical feed stocks, for example, from using different suppliers, can result in the introduction of contaminants as well. The result of contamination may be ... 

Use phenols and caustics produced in the refining operations as chemical feeds in other applications. 

Some businesses are all around good excuses for acquiring most any suspicious chemicals Feed Additives for livestock and poultry Plastic, Petrochemical, or Biomedical Research Laboratories Analytical or Consulting Laboratories Chemical Manufacturing Company and Chemical Supply... 

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