Design and evaluation of delayed cokers and visbreakers is a THI specialty. THI has designed, fabricated and done troubleshooting and debottlenecking on both single and double-fired coker heaters in multi-cell configurations with duties up to 260 MM BTU/hr (76 MW). This engineering effort is supported by a unique proprietary complex computer model that accurately predicts key parameters such as % conversion to coke and cracked material and residence time in the coil.