HYDRODEOXYGENATION OF OILS FROM CELLULOSE IN SINGLE AND 2-STAGE HYDROPYROLYSIS

To investigate the removal of oxygen (hydrodeoxygenation) during the h ydropyrolysis of cellulose, single and two-stage experiments on pure c ellulose have been carried out using hydrogen pressures up to 10 MPa a nd temperatures over the range 300-520 degrees C. Carbon, oxygen and a romaticity balances have been determined from the product yields and c ompositions. For the two-stage tests, the primary oils were passed thr ough a bed of commercial Ni/Mo gamma-alumina supported catalyst (Crite rion 424, presulphided) at 400 degrees C. Raising the hydrogen pressur e from atmospheric to 10 MPa increased the carbon conversion by 10 mol e % which was roughly equally divided between the oil and hydrocarbon gases. The oxygen content of the primary oil was reduced by over 10% t o below 20% w/w. The addition of a dispersed iron sulphide catalyst fu rther increased the oil yield at 10 MPa and reduces the oxygen content of the oil by a further 10%. The effect of hydrogen pressure on oil y ields was most pronounced at low flow rates where it is beneficial in helping to overcome diffusional resistances. Unlike the dispersed iron sulphide in the first stage, the use of the Ni-Mo catalyst in the sec ond stage reduced both the oxygen content and aromaticity of the oils.