|Port of Brownsville Director Eduardo Campirano|
Not surprisingly, the Port of Brownsville, an entity that should be self-supporting with proper leadership, continues to rely on millions of dollars of locally-generated taxpayer monies to continue operation. Port Director Campirano, in a Brownsville Herald Letter to the Editor, has the audacity to push for the proposed LNG plants to be strewn from the Port of Brownsville to near the city limits of Port Isabel. While parroting the platitudes of Big Oil and Gas, Camparino gives us his schoolgirl description of LNG:
"LNG is the liquefied form of the natural gas that people use in their homes for cooking and heating, and has been safely handled for many years." (Eduardo Camparino, Letter to the Editor, Brownsville Herald, 10/5/2015.)
Yes, doofus, but LNG plants do not simply burn natural gas like grandma heating tortillas on her two burner range!
The purpose of an LNG plant is to condense natural gas into a liquid so it can be shipped economically. That process, extremely complex, requires an ENORMOUS amount of energy and releases hydrocarbons, mercury, hydrogen sulfide and other contaminants into the atmosphere. Millions of gallons of hot effluent must also be disposed daily, likely in our case, into the pristine estuaries and bird sanctuaries of eastern Cameron County.
The Chyoda Corporation of Yokohma, Japan, builder of the world's largest LNG plants, explains the process:
A liquefied natural gas plant (LNG plant) is roughly divided into five processes: (1) pretreatment, (2) acid gas removal, (3) dehydration, (4) liquefaction and (5) heavy oil separation.
(1) In the pretreatment process, undesired substances are removed from the gas taken from a gas field. Then the gas is separated using a slug catcher into oil and water which are
(2)Natural gas taken from a gas field contains environmental pollutants like hydrogen sulfide (H2S) and carbon dioxide (CO2). These impure substances are absorbed and removed from natural gas with an amine absorber (acid gas removal or AGR). With the use of a sulfur removal unit (SRU), sulfur is extracted from the hydrogen sulfide in the removed pollutant.
(3)An adsorbent is used to remove water from the natural gas from which impure substances have been removed so that ice will not form during the subsequent liquefaction process.
(4)Traces of harmful mercury are removed before liquefaction.
|Sulfur Removal Unit|
(5)The heavy compounds separation process is the core of an LNG plant in which natural gas is cooled and liquefied to –160°C or less using the principle of refrigeration. Because gas is cooled and liquefied to an extremely-low temperature during the process, an enormous amount of energy is consumed. How much this energy can be reduced is important, so various ingenious processes have been proposed and commercialized.
Major liquefaction processes are as follows:
1)C3-MR method: The C3-MR method is currently the main method. Propane and mixed coolants (nitrogen, methane, ethane and propane) are used as the coolant (APCI), and an improvement on this method called the AP-X method is also used for large LNG plants.
2)AP-X method: As liquefaction trains get larger, they approach a limit on the size of heat exchanger that can be produced and transported. This process can increase LNG production capacity by adding LNG sub-coolers with nitrogen coolant used according to the C3-MR method, without increasing the size of the main heat exchanger (APCI).
3)Cascade method: This method sequentially uses propane, ethylene and methane as the coolant (Phillips).
4)DMR method: This method uses two kinds of mixed coolants (an ethane and propane mix and a nitrogen-methane, ethane and propane mix) (Shell).
5) SMR method: This method is called the PRICO process and uses only one kind of mixed coolant (Black & Veatch).
All of these methods require enormous refrigeration compressors. Gas turbines used for giant power plants are used to drive them, so elaborate engineering based on experience and high-level knowledge is required to design, produce and assemble the compressors and gas turbines.