Biomass is a neutral carbon-potential solid fuel and, hence, it is environmentally friendly. However, biomass is characteristically hygroscopic, has a high-moisture content, a low calorific value, low resistance to biological degradation, and several storage issues. Therefore, torrefaction has received much attention in the last decade from researchers to overcome the problem because it can potentially improve the quality of biomass for fuel. This study examined the biomass pre-treatment technique and torrefaction for producing high-quality solid fuel. The empty oil palm bunches (EFBs) were soaked in 10% wt, 18% wt, and 26% wt of acid peroxide solution and demineralized water for 15, 60, and 120 minutes, respectively. Next, the EFBs were torrefied at 300 °C for 60 minutes. The 18% wt acid peroxide solution pre-treatment for 120 minutes has shown the best result with an ash content of 3.94% wt, volatile matter of 32.42% wt, and fixed carbon of 64.08% wt. Furthermore, the 60-minute demineralized water pre-treatment achieved the best results, reducing the potassium content by 30% (from 1.650% wt. to 1.144% wt.) and the chlorination by 48% (from 0.031% wt. to 0.016% wt.). The quality of EFB after burning largely meets the standards set by SNI 8675:2018. It has a maximum density of 0.8 g/cm3, a maximum water content of 12% wt., a maximum ash content of 5% wt., and a volatile matter content of 80% wt.