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NCEES PE Agricultural and Biological Engineering Food & Dairy Engineering: practice questions

NCEES PE Agricultural and Biological Engineering · USA · NCEES (ASABE is the content partner)

Original practice questions written to the published syllabus · not past papers
10worked here, free
30written to this exam in this subject
12syllabus units

About NCEES PE Agricultural and Biological Engineering

NCEES PE Agricultural and Biological Engineering is a licensing and registration exam run by NCEES (ASABE is the content partner), for candidates in USA. Computer-based, 85 questions, 9.5-hour appointment (8.5 hours of exam). Once a year (next: 28 Oct 2026). Closed book with the electronic NCEES handbook and supplied searchable ASABE standards; SI and US customary units.

Source: ncees.org.

Checked against the exam body's published information. Formats and fees change; confirm the current edition there before you book.

Food & Dairy Engineering in NCEES PE Agricultural and Biological Engineering

Unit operations of food and milk plants: balances, fluid flow, heat exchange, thermal processing, evaporation, separation, freezing and hygienic design.

Our 30 NCEES PE Agricultural and Biological Engineering questions in this subject: 0 easy, 20 medium, 10 hard, across 12 units.

10 practice questions, worked

Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.

These 10 were written to NCEES PE Agricultural and Biological Engineering and are not shown on any other exam's page.

Question 1 · hard

Cream at 40 % fat is to be diluted with skim milk at 0.05 % fat to make 500 kg of cream at 12 % fat. The mass of 40 % cream needed is closest to

  1. 214 kg
  2. 150 kg
  3. 350 kg
  4. 120 kg
Answer and working

B. 150 kg

m_cream = 500 × (12 − 0.05)/(40 − 0.05) = 500 × 11.95/39.95 = 149.6 kg; skim = 350.4 kg. 350 kg is the skim, not the cream. Here the skim fat is so small that ignoring it changes the answer only in the first decimal, but the full balance should still be written. 214 kg divides by 40 − 12 instead of 40 − 0.05 (500 × 12/28).

Question 2 · medium

A viscous product (ρ = 1100 kg/m³, μ = 0.05 Pa s) flows at 0.5 m/s through 20 m of 25 mm bore pipe. The frictional pressure drop is about

  1. 12.8 kPa
  2. 25.6 kPa
  3. 6.4 kPa
  4. 102 kPa
Answer and working

B. 25.6 kPa

Re = 1100 × 0.5 × 0.025/0.05 = 275, laminar. Δp = 32 μ L v/D² = 32 × 0.05 × 20 × 0.5/0.025² = 25,600 Pa. Using the Fanning factor in the Darcy equation gives a quarter of this (6.4 kPa). 12.8 kPa drops the 2 from Δp = 2fρv²L/D with the Fanning f = 16/Re; 102 kPa enters the radius (12.5 mm) for D.

Question 3 · hard

A centrifugal pump handling hot condensate near its boiling point starts to make a crackling noise and its delivery falls. The most likely cause and remedy are

  1. Cavitation; raise the NPSH available by raising the supply level or cooling the liquid
  2. Air leak on the discharge; tighten the discharge fittings and fit a larger impeller to restore flow
  3. Motor overload; fit a larger motor
  4. Excess viscosity; heat the liquid further
Answer and working

A. Cavitation; raise the NPSH available by raising the supply level or cooling the liquid

Hot liquid near saturation has high vapour pressure, lowering NPSH available; vapour bubbles form and collapse (cavitation). Raising static suction head, reducing suction losses or cooling the liquid restores NPSHa above NPSHr. Heating further makes it worse.

Question 4 · medium

Hot water cools from 80 to 60 °C while milk heats from 10 to 55 °C in counter-current flow. The LMTD is

  1. 37.5 K
  2. 45.0 K
  3. 24.6 K
  4. 36.1 K
Answer and working

D. 36.1 K

End differences: 80 − 55 = 25 K and 60 − 10 = 50 K; LMTD = (50 − 25)/ln(50/25) = 36.1 K. 24.6 K is the co-current value (70 and 5 K ends); 37.5 K is the arithmetic mean. 45 K is the milk's temperature rise, not a temperature difference.

Question 5 · medium

When steam condenses on one side of an exchanger, the effectiveness–NTU relation becomes ε = 1 − e^(−NTU) because

  1. Latent heat equals sensible heat
  2. Condensing steam has zero film coefficient, so its thermal resistance dominates
  3. The condensing fluid has effectively infinite heat capacity rate, so C_r = 0
  4. The flow arrangement must be parallel
Answer and working

C. The condensing fluid has effectively infinite heat capacity rate, so C_r = 0

At constant condensing temperature C_max is infinite and C_r = C_min/C_max = 0; all flow arrangements then share ε = 1 − exp(−NTU).

Question 6 · hard

A can is held at a constant 115 °C for 30 min. With z = 10 °C and reference 121.1 °C, the F₀ delivered is about

  1. 18.3 min
  2. 30 min
  3. 122 min
  4. 7.4 min
Answer and working

D. 7.4 min

L = 10^((115 − 121.1)/10) = 0.245; F₀ = 30 × 0.245 = 7.4 min. Reversing the exponent sign gives 122 min, more lethality at a lower temperature, which is absurd. 18.3 min multiplies the time by the exponent 0.61 instead of by 10^−0.61.

Question 7 · medium

A viscous mix flows laminar at 10,000 L/h through a holding tube of 47.5 mm bore and must be held 15 s. The minimum tube length is about

  1. 47 m
  2. 28.7 m
  3. 11.8 m
  4. 23.5 m
Answer and working

A. 47 m

A = π/4 × 0.0475² = 1.772e-3 m²; mean v = 2.778e-3/1.772e-3 = 1.57 m/s; laminar v_max = 3.14 m/s; L = 3.14 × 15 = 47.0 m. Designing on mean velocity gives 23.5 m; the turbulent ratio gives 28.7 m. 11.8 m uses the bore as the radius in the area (π × 0.0475²).

Question 8 · medium

A single-effect evaporator removes 3667 kg/h of water from milk. Feed enters at its boiling point; latent heat of vaporisation is 2358 kJ/kg and of the heating steam 2202 kJ/kg. The steam economy is about

  1. 0.93
  2. 2.0
  3. 0.86
  4. 1.07
Answer and working

A. 0.93

S = 3667 × 2358/2202 = 3926 kg/h; economy = 3667/3926 = 0.93. Inverting gives 1.07. 0.86 is the value if feed enters cold at 20 °C. 2.0 is a typical double-effect economy, not a single-effect one.

Question 9 · medium

1000 kg/h of concentrate at 48 % TS is spray dried to a powder of 3.5 % moisture (wet basis). The water evaporated is about

  1. 497 kg/h
  2. 485 kg/h
  3. 503 kg/h
  4. 520 kg/h
Answer and working

C. 503 kg/h

Powder = 480/0.965 = 497.4 kg/h; water = 1000 − 497.4 = 502.6 kg/h. 497 kg/h is the powder, and 520 kg/h ignores residual moisture. 485 kg/h adds 3.5 % of the feed (35 kg) as residual moisture to the solids.

Question 10 · medium

Raw milk that is homogenised and then held before pasteurisation is liable to develop

  1. Cream plug formation
  2. Sweet curdling from rennet
  3. Rancid flavour from rapid lipolysis
  4. Increased vitamin content
Answer and working

C. Rancid flavour from rapid lipolysis

Homogenisation creates new fat surface not protected by native membrane, and milk lipase then attacks the fat quickly. Milk is therefore homogenised warm and pasteurised immediately.

A study plan for Food & Dairy Engineering in NCEES PE Agricultural and Biological Engineering

This plan follows where our questions actually fall, so the time goes where the marks are likely to be. It is our reading of the syllabus, not the exam body's weighting.

  1. First, the heavy units (47% of the 30 questions): Cleaning-in-place and sanitary design (4, 13%); Heat exchangers: plate, tubular and scraped-surface (4, 13%); Fluid flow in food plants: pumps, pipes and rheology (3, 10%); Homogenisation (3, 10%).

    Read the manual chapters for these first and do every worked question you can find on them.

  2. Then the middle band: Material and energy balances (3, 10%); Pasteurisation: HTST and LTLT (3, 10%); Evaporation: single and multiple effect (2, 7%); Freezing and Plank's equation (2, 7%).

    Aim for one sitting per unit, then mixed questions across them.

  3. Then the lighter units: Spray and drum drying (2, 7%); Thermal processing kinetics: D, z and F values (2, 7%); Filtration and membrane processes: MF, UF, NF and RO (1, 3%); UHT processing and sterilisation (1, 3%).

    Learn the definitions, classifications and standard numbers; these units are more often recalled than worked.

  4. Leave time for the hard ones: Filtration and membrane processes: MF, UF, NF and RO (1 hard of 1), Material and energy balances (2 hard of 3), Heat exchangers: plate, tubular and scraped-surface (2 hard of 4).

    Come back to these after a first pass, untimed, and read every explanation, including for the options you rejected.

  5. Finish timed. Sit the subject as a timed set without notes, mark it, and send each wrong answer back to its unit above.

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