Formaldehyde Production Flowsheet from Methanol

Formaldehyde Production
Material Balance flow sheet

 Formaldehyde manufacturing technologies have developed some of the process methods for the production of formalin based on raw materials,

• Reduction of carbon oxides process
• Hydrocarbon gases conversion
• Oxidation of methane

Formaldehyde production flowsheet represented above with material balance over the types of equipment. In this process, methanol is used as a raw material. Two process option available when methanol used as raw material :

• Oxidative – dehydrogenation process
• Pure oxidation process

Physical Properties of Formaldehyde:

1. Pure formaldehyde solutions are colourless and clear. Opalescence or cloudiness is caused by polymer precipitation. It has an irritating odour

2. It is soluble in water, alcohol and polar solvents, slightly soluble in hydrocarbons, chloroform, ether.

3. Various grades of formaldehyde are CP gas, 37% aqueous solutions, trioxane polymer (CHO), Paraformaldehyde, (CHO)_{n .} nH₂O, where n=10-50.

4. Molecular weight    = 30.03

5. Boiling point           = -19⁰C

6. Melting point          = -118⁰C

7. Refractive index     = 1.3773.

8. Toxicity limits        = 10ppm

9. Density = 37% formaldehyde containing 9.2% methanol at 18⁰C is 1.0895.

10. Lower explosive limit = 7 vol. % in air

11. Upper explosive limit = 73 vol. % in air

12. Solutions containing 15% methanol, of specific gravity 1.0775 at 15 to 23.7⁰C has a

       dielectric constant of 45.0.

13. Expansion coefficient of formaldehyde = 0.00057

14. Flash point of formaldehyde (37wt %) = 64⁰C

15. Partial Pressure of formaldehyde (37 wt %) at 35⁰C = 4.2mm Hg.

16. Resistivity of commercial formaldehyde solution at 30⁰C = 35000 to 37000 ohms.

17. Absolute viscosity of formaldehyde at 25⁰C = 2.58 centi poise.

18. Heat of combustion   = 134.1 Kcal/gmol.

19. Heat of formation      = -27.70 Kcal/gmol.

20. Free energy                = -26.266 Kcal/gmol.

21. Heat capacity             = 8.461 cal/gmol ⁰C.

22. Entropy                      = 8.461 cal/gmol ⁰C.

23. Heat of vaporization at boiling point (19.2 ⁰C) = 5.570 Kcal/gmol.

24. Heat of solution         = 15 kcal/gmol.

25. Heat of dilution         = 0.45 Kcal/gmol.