Thermodynamic analysis and process optimization of a natural gas liquid recovery unit based on the Joule – Thomson process

This paper demonstrates a method of recovering the low pressure vapor from the condensate tanks in the Bibiyana gas field. This method uses a gas ejector as a device to compress the low pressure natural gas from the condensate tanks to an intermediate pressure, which would then be fed into the intermediated stage of the existing vapor recovery unit. Thus the natural gas will be saved which would have been otherwise flared. The amount of tank vapor is estimated by different methods, which shows a significant amount of gas is now being flared. Flaring of gas is a problem which entails both economic loss and environmental concerns. It is estimated that, on the average 190 MSCFD tank vapor can be recovered using the proposed method involving a gas ejector. Thus yearly saving would be about 68 MMSCF of natural gas. The equivalent heat energy saving is about 74.55X109 BTU. In terms of greenhouse gas emissions, this project will reduce about 1,112 tons of CO2 emissions per year in the gas plant locality. DOI: http://dx.doi.org/10.3329/jce.v27i1.15856 Journal of Chemical Engineering, IEB Vol. ChE. 27, No. 1, June 2012: 37-41

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Exergy Analysis of Natural Gas ICE-Based CHP System

ASME 2009 3rd International Conference on Energy Sustainability, Volume 2 ◽

10.1115/es2009-90013 ◽

2009 ◽

Cited By ~ 1

Author(s):

Xiling Zhao ◽

Lin Fu ◽

Shigang Zhang ◽

Jianzhang Zhu ◽

Baomin Huang ◽

...

Keyword(s):

Natural Gas ◽

Heat Recovery ◽

Waste Heat ◽

Operation Mode ◽

Mode I ◽

Mode Ii ◽

Exhaust Gas ◽

Liquid Desiccant ◽

Water Flows ◽

Recovery Unit

A challenge for CHP (Combined heating and power) system is the efficient integration of distributed generation (DG) equipment with thermally-activated (TA) technologies. Tsinghua University focuses on laboratory and demonstration research to study the critical issues of CHP systems, advance the technology and accelerate its application. The Research performed at the Building Energy Research Center (BERC) Laboratory focuses on assessing the operational performance and efficiency of the integration of current DG and TA technologies. The test system is composed of a 70-kW natural gas-fired internal combustion engine (ICE) with various heat recovery units, such as a flue gas-to-water heat recovery unit (FWRU), a jacket water heat recovery unit (JRU), liquid desiccant dehumidification systems (LDS), an exhaust-gas-driven double-effect absorption heat pump (EDAHP), and a condensation heat recovery unit (CRU)). In the winter, the exhaust gas from the ICE is used in the FWRU (operation mode I) or used to drive the EDAHP directly, and the exhaust gas from the EDAHP is used in the CRU (operation mode II). The water flows from the CRU can be directed to the evaporator side of the EDAHP as the lower-grade heat source. The water flows from the condensation side of the EDAHP, in conjunction with the jacket water flows from the JRU, is used for heating. In summer, the exhaust gas from the ICE is used to drive the EDAHP for cooling directly, and the waste heat of the jacket water is used to drive the liquid desiccant dehumidification systems, to realize the separate control of heat and humidity. In this paper, the exergy and energy analysis has been done on operation mode I and II according to the actual testing results, and it is show that the exergy efficiency of operation mode II is improved by 1.5% than operation mode I, and the energy efficiency of operation mode II is improved by 11% than operation mode I. The only way to improve the whole CHP is to maximize the use of the heat recovered by the ICE and to utilize the remaining heat of exhaust gas in other waste-heat driven equipments capable of using low grade waste heat like the CRU.

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