Dry chemical feed calculators

Feed rate results in Ib/day or g/hr can be converted to Ib/hr, kg/day, or m /day using the conversion factors given in the previous section on full-strength dry chemical feed calculations. Other conversion factors are provided in Appendix B. 

Gas Chemical Feed Calculators 135 Dry Chemical Feed Calculators 141 Liquid Chemical Feed Calculators 142... 

Liquid chemical feed calculations are the subject of chapter 8. This chapter includes the calculations for dry chemical feed either directly into process water or first into dissolving or slurry tanks, and to prepare solution batches. All dry chemical feeders are calibrated as needed to ensure accurate delivery of the chemical. 

Calculators c6-l and c6-2 can be used for many dry chemical feed situations. If the flow measurement or feed rate setting is in different units, the units should be converted in these calculators. Conversion formulas are provided for some of the more common units. For example, to use calculator c6-l when the flow is in gallons per minute, the units can be converted to milhon gallons per day (mgd), and the value plugged in. The result will be a feed rate in pounds per day (Ib/day). If the feed rate is in pounds per hour (Ib/hr), the following formula can be used. 

Some dry chemicals contain varying amounts of the active ingredient for chemical application. The chemical feed calculations then require an adjustment for the amount of the active ingredient available in the dry chemical. Examples of this type of chemical... 

Chemical feed calculations for dry chemicals where the percent active ingredient or purity is not 100 percent are based on the dosage of the active ingredient or desired chemical (c6-3 and c6-4). 

Full-Strength Chemical Feed Calculations 67 Percent Active Ingredient Chemical Feed Calculations 68 Solution Preparation Using Dry Chemicals Batch Preparation Calculations 70... 

Dry chemicals are sometimes fed directly into a well-mixed process water stream. More often they are mixed with water in a dissolving tank or to prepare a slurry. The concentrated solution or slurry is then fed into the process water stream (see Figure 5-8). Calculating the feed rate for these systems is identical. The dry chemicals are considered full-strength (100 percent of the chemical being fed). This approach is useful when reviewing chemical inventory to make reorder decisions. Some operators still calculate the feed rate for dry polymers by adjusting for the purity (percent solids) of the dry material. It is more common, however, to consider whatever is delivered in the bag is pure polymer, and this would apply to the calculations in this section. 

The percent active ingredient is often provided by the chemical manufacturer. This information is needed in some cases because the dry chemical may contain unknown amounts of inert substances needed to prevent caking or other storage and feed problems. If the complete dry chemical formula is known, the percent active ingredient can be calculated from the formula using the atomic weights of the elements (Appendix E). 

Calculators 8-1 and 8-2 (identical to dry feed calculators 6-1 and 6-2) can be used to determine the feed rate of pure chemical for a given dosage and flow rate. These are often used for liquid polymers (polyelectrolytes) where the polymer in the delivery drum is fed directly to the point of application without dilution. 

The DOM value was calculated from the organic matter and OMd. For the majority of feed materials, the DOM data come from measurements (literature and/or INRA). For dehydrated alfalfa and for dehydrated grass, OMd was predicted from the chemical composition given in the tables and INRA equations linking OMd and the crude fibre content (expressed in % dry... 

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