Flare Emissions- Recent Regulatory Activity, and Review of Flare Destruction Efficiency

摘要

Flaring has traditionally been used in the oil and gas industry for disposal of production gas in areas where collection and treating are not economic, and for the safe destruction and venting of gas from emergency depressurization and maintenance activities at refineries, gas plants and chemical facilities. Recently the total emission from flares, the composition of gases being flared, and flare destruction efficiency have received increased regulatory attention. The impetus is public concern that the quantity of gas being flared is excessive, and a perception that a significant potion of the flared gas may not get destructed. Also, smog issues in populated areas have initiated review of all volatile organic hydrocarbon (VOC) sources.The Alberta Energy and Utilities Board issued regulations in December 2002 with the intent to reduce the quantity of flared and incinerated gas in Alberta to 25 billion standard cubic feet per year (scf/yr), from 50 billion in 1996 and 31 billion scf/yr in 2000. To accomplish this the board set up a decision tree for the evaluation of new and existing sources of gas from oil production, and rules that specify when this gas must be conserved. The associated gas from new crude production with a gas-oil content of 3000 ft~3 gas/ft~3 oil must be conserved. For existing production, the associated gas must be conserved if conservation is determined to be economic. The regulations consider gas conservation to be economic if the incremental economics of gas conservation generate a net present value before tax greater than zero. They also set guidelines for flaring for maintenance and other routine activities for oil and gas production and gas plants. Limits were set on the total quantity of gas that can be flared from gas plants as a percentage of yearly production.