SYNGAS PROCESSING AT LONG LAKE

摘要

Long Lake is Canada's fourth major integrated oil sands operation (70 000 barrels per day) and combines Steam Assisted Gravity Drainage (SAGD) with OrCrude™ technology, hydrocracking and gasification to produce a premium synthetic crude oil. The OrCrude™ technology, using conventional distillation, solvent de-asphalting and thermal cracking, separates the produced bitumen into partially upgraded sour crude oil and liquid asphaltenes. The hydrocracker upgrades the sour crude oil to a light (39° API) premium synthetic sweet crude oil, and in the gasifiers the liquid asphaltenes are converted to syngas. This paper is about the operational experiences with processing the sour syngas to produce hydrogen for the hydrocracker and low-cost fuel for generating steam for SAGD and electricity. A Selexol™ unit removes the contaminants (H_2S, COS, Fe and Ni carbonyls). Severe fouling of the Selexol™ rich lean heat exchanger is managed by regular in-situ cleaning and by increasing the pressure of the flash vessel, which diminishes the decomposition of carbonyls on the heat exchanger. We also must manage corrosion in the heat exchanger and reboiler. A Claus unit processes a number of acid gas and ammonia streams. Claus catalyst life cycle was short due to contamination. Discussed is how we have found the source of the contamination. The Long Lake PSA, one of the largest hydrogen purification units in the world, is processing clean non-shifted syngas. Discussed is how deteriorating hydrogen recovery was tackled with a valve maintenance program.