# What is Material balance: Definition and 14 Discussions

A mass balance, also called a material balance, is an application of conservation of mass to the analysis of physical systems. By accounting for material entering and leaving a system, mass flows can be identified which might have been unknown, or difficult to measure without this technique. The exact conservation law used in the analysis of the system depends on the context of the problem, but all revolve around mass conservation, i.e., that matter cannot disappear or be created spontaneously.Therefore, mass balances are used widely in engineering and environmental analyses. For example, mass balance theory is used to design chemical reactors, to analyse alternative processes to produce chemicals, as well as to model pollution dispersion and other processes of physical systems. Closely related and complementary analysis techniques include the population balance, energy balance and the somewhat more complex entropy balance. These techniques are required for thorough design and analysis of systems such as the refrigeration cycle.
In environmental monitoring the term budget calculations is used to describe mass balance equations where they are used to evaluate the monitoring data (comparing input and output, etc.). In biology the dynamic energy budget theory for metabolic organisation makes explicit use of mass and energy balance.

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1. ### Engineering Hydroprocessing Unit material and energy Balance

1.1) 1 m3 of residue feed has a mass of 1030 kg. Mass of H2 consumed=(1.27 kg of H2 consumed/100 kg of residue feed)*1030 kg of residue feed=13.081 kg We can treat H2 as an ideal gas to calculate its volume at normal conditions 101325*V=(13.081/2.016)*1000*8.3145*273.15 V=145.436 m3 normal/m3...
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### Combustion of Toluene with 30% excess air (Himmelblau)

Homework Statement Toluene, C7H8, is burned with 30% excess air. A bad burner cause 15% of the carbon to form soot (pure C) deposited on the walls of the furnace, what is the Orsat analysis of the gases leaving the furnace?Homework Equations C7H8 + 9 O2 => 7 CO2 + 4 H2O 30% excess of air What...
3. ### Material balance with a reaction (chemical engineering)

Homework Statement Felder & Rousseau 4.73 (p. 184) A mixture of propane and butane is burned with pure oxygen. The combustion products contain 47.4 mole % H2O. After all of the water is removed from the products, the residual gas contains 69.4 mole% CO2 and the balance is O2. What is the mole...
4. ### How to calculate mass of air in mass balance?

What is the general procedure for calculating the mass of air in mass balance problems? what assumptions must be made? How do i convert this into mass from a percentage, e.g 21% oxygen & 79% nitrogen?
5. ### How to Solve a Material Balance Problem for Two Liquids A and B?

Two liquids, A and B, are mixed together. A is 5.00% solids, the rest water. B is 11.0% solids, the rest water. To the mixture is added 18.5 kg of bone-dry solids resulting in a mixture of 2 150 kg containing 8.25% solids. What were the original amounts of the liquids A and B?
6. ### Solving Material Balance Problems in Evaporators

I have an issue with this question: An aqueous solution containing 15% NaOH and 0.5% NaCl is concentrated at a rate of 100 kg/min in an evaporator. The concentrated solution is then mixed with 2000 kg of aqueous NaOH solution in a mixer. At the end of one hour a sample is collected from the...
7. ### Material Balance Lead in a lake

Homework Statement Question 2. Tetraethyl lead was used in early model cars to help reduce engine knocking, boost octane ratings, and help with wear and tear on valveseats within the motor. In Australia, our petrol contained lead between approximately 1950 and 2002. Consider the impact of...
8. ### Material Balance: Determine Minimum Ditch Length for 90% Odour Reduction

Homework Statement Question 1. An industry uses a long drainage ditch to break down their wastes and in particular to remove the odour. The waste travels along the ditch at a velocity of 0.5 m/h. The odour is reduced as a first order reaction with a reaction constant of k=0.30 day-1 The...
9. ### Material Balance Problem Involving Ideal Gases- Any ?

Homework Statement A furnace is fired with 1000 feet cubed per hour at 60 degrees F and 1 atm of a natural gas containing the following volumetric analysis: CH4: 80%, C2H6: 16%, O2: 2%, CO2: 1%, and N2: 1%. The exit flue gas temperature is 800 degrees F and the pressure is 760 mm Hg absolute...
10. ### Material balance help, chemical engineering

Homework Statement Toluene is recovered from a mixture of toluene and nitrogen (containing 52 mol% toluene) by cooling the mixture at constant pressure of 1.2 bar to condense out some of the toluene. If the flow rate of the mixture into the condenser is 179 kmol h-1, determine the flowrate of...
11. ### Material balance- purge cycle help

I am really struggling to get to grips with this question, ( struggling with material balance overall!) I can do dimple material balance however for things with a recycle stream or purge stream, really confuses me. I have the solution which I will post up, but I still don't get 'why' it...
12. ### Deceptively difficult material balance problem. HELP

I have been working on what I thought was an easy problem. This was a one hour quiz in which the whole class failed, the instructor decided to give it as a homework assignment instead. ------problem start--------- Considerable interest exists in the conversion of coal into liquid products...
13. ### How Is Material Balance Calculated in Distillation?

Homework Statement Question: A mixture of 40/60 mole% pentane/heptane is to be separated to give a top product of 95 mole% pentane and a bottom product of 5 mole% pentane. The column will operate at 1 bar witha reflux ratio of 0.5 kmol/kmol. It will have a total condenser and a partial...
14. ### What Is the Optimal Selling Price for a Paint Mixture with 17.0% Pigment?

A paint mixture containing 25.0% pigment and the balance water sells for $18.00/kg, and a mixture containing 12.0% pigment sells for$10.00/kg. If a paint retailer produces a blend containing 17.0% pigment, for how much (\$/kg) should it be sold to yield a 10% profit? Am I wrong, or are they...