Major Pharmaceutical Client
Cogeneration Project
Puerto Rico
This pharmaceutical client, as part of a corporate goal to reduce greenhouse gases, targeted a new facility in Puerto Rico as a potential site to demonstrate their commitment. Paulus, Sokolowski and Sartor (PS&S)/KeySpan provided a comprehensive study of central plant energy alternatives that could be integrated with the planned boiler and emergency generation facility.
The study focused on a range of available boiler and generator technologies to reduce overall carbon dioxide (CO2) emissions applicable to this site including upgraded boilers with a steam turbine, gas turbine generators and diesel generators of up to a 3.2 MW capacity. For each alternative, a detailed analysis provided cost savings based on the proposed local utility Puerto Rico Electric Power Authority (PREPA) tariff structure. More importantly, for each Combined Heat and Power (CHP) facility, the projected site emissions increases and corresponding CO2 reduction were tabulated so that the relative benefit of each alternative could be weighed from both economic and emissions perspectives.
The site proved a challenge in that natural gas, the fuel of choice to reduce emissions, is not available on that part of the island. Emissions reduction had to be attained while using No. 2 fuel oil as the only fuel source. A separate initiative to review the use of biofuel was not part of this study.
The recommended design for this project uses two 1.6 MW diesel generators with both exhaust and jacket water heat recovery systems. The plant is designed to run parallel with the grid for reliability, and automatically switch to the isolated mode, which provides standby power during utility outages. Grid power in the area is historically unreliable, with an average of four to five outages or transients during each year. Each of these could cause loss of product for the new facility, incurring a significant economic penalty. The CHP equipment is designed for maximum reliability, and the capacity to stabilize incoming power and ride through an event, whenever possible.
The plant design also maintains overall nitrogen oxide (NOx) emissions from the new pharmaceutical plant within limits of the originally designed boiler plant while utilizing substantially more diesel fuel. This is accomplished by working with the equipment suppliers to furnish a state-of-the-art Selective Catalytic Reduction system capable of reducing oxides of nitrogen by 98%. An oxidation catalyst also reduces carbon monoxide and unburned hydrocarbon emissions from the generators.
The generation plant is a key component of a major facility expansion. The implementation of cogeneration provides the reliable power supply that a manufacturing facility demands.