NG4S259 Industrial Heating Systems Assessment

Coursework brief

A 8m (L) × 4m (W) × 2.5m (H) industrial furnace (Figure 1) is initially melting copper at a rate of 8.0 tonne/hr. The furnace operates on a continuous basis under essentially steady-state conditions. The natural gas-fired (assume fuel composition is 100% methane) burners which are installed, have a maximum thermal capacity of 3.5 MW and can operate with a turndown ratio of 4:1. The furnace structure is constructed of thin steel shell (negligible thermal resistance) lined with dual-layer insulation composed of ceramic fibre (10 cm thickness) and mineral wool (6 cm thickness). The convection coefficient of the furnace outer surface is observed to be 10 W/m2/K whilst its surface emissivity is 0.8. The load surface (surface 1) emissivity can be taken as 0.6 and the furnace walls and roof can be considered as a single surface (surface 2) with emissivity of 0.7. Convection heat transfer within the furnace can be neglected.

Given that the furnace is operating initially at 5% excess air and without waste heat recovery, determine the furnace efficiency (%) and specific fuel consumption (GJ/tonne).

Upon your initial calculation of the furnace performance, investigate the influence of excess air and waste heat recovery on the furnace efficiency and productivity. Submit your work as individual report of no more than 2000 words.

Report format:

• Introduction

Clear outline the aims and objectives of the report. (circa 200 words)

Example:

Aim:

To investigate the relationship between tectonic-plate movement and the gravitational effect of the alignment of the major planets.

Objectives:

• Data sets will be extracted from the known historical record of tectonic-plate movement
• Data sets will be extracted from astronomical tables detailing the various alignments of the major planets covering the same period as data from the geological record.
• The data from both sets will be synthesised to establish if correlation points exist between major geological events and planetary alignments.

• Description of the furnace model

Using Figure 1 as reference, briefly describes the methodology used in furnace modelling. (circa 600 words)

• Results and discussion

This section should include all relevant results obtained from the furnace simulations. Critical analysis and discussion of the results should be carried out, leading to a clear set of findings pertinent to the furnace behaviour. Graphical presentation of results should be adopted wherever possible. All temperatures should be presented in degree Celsius, mass flowrate (fuel, air, exhaust gases) in kg/hr, Heat transfer in kW, specific fuel consumption in GJ/tonne, furnace production rate in tonne/hr, furnace efficiency in %, excess air in %, effectiveness of heat exchanger in %.

(circa 1000 words)

• Conclusions

This section gives you the opportunity to elaborate on the significance of your findings. You should also summarise your thoughts and convey the wider implications of your study. 

(circa 200 words)

• References

You should not merely provide a list of materials that you have read. References should be cited appropriately within the report as evidence of supporting your assumptions, results, and discussion.