Fred Starr recollects: unforgotten and unforgiven
Fred Starr recollects his first endeavour with a combined cycle gas turbine.
In 1991, I was present at the death of a technological dinosaur. It was the last conference I went to where the sole focus was coal fuelled steam plants. The incoming asteroid was the decision by the UK Government, in the wake of the 1984 Miners Strike, to allow natural gas to be used in power stations. It was a fuel best exploited by a new type of power plant – the combined cycle gas turbine (CCGT).
CCGTs didn’t get a mention at the meeting. It was the usual suspects – creep resistant steels for steam turbines, superheaters, and boilers. In true Jurassic World fashion, all that was on offer were bigger power plants, which were not that much better. Steam temperatures would stick at 565°C. In the memory of designers and operators, rankled the misbegotten attempts in the 1960s to go higher. Retreat had been ignominious and obvious. Particularly in the USA, where in shooting for 650°C, plants like the one at Eddystone, needed a significant downrating. Although we in Britain had gone for a fairly modest 593°C, as at the power station at Drakelow, ratcheting, the progressive increase in length of its pipework – a result of thermal fatigue – meant that the stairways up the sides of the boiler had to be periodically extended.
The only novel paper was on heat recovery steam generators, or HRSGs as they are now called. I wondered what they were. They sounded boring, temperatures and pressures so low there were no metallurgical challenges. The speaker didn’t bother to explain what they were used for, and as there were no questions, the conference moved onto more familiar topics. Unaware that, in Britain, at least, extinction of a well loved technology was at hand.
To be honest, I had not expected much from the conference. The main attraction was a trip by coach over the Pennines to Roosecote, near Barrow-in-Furnace, where Britain’s first CCGT was being built.
It was symptomatic that the coach was cancelled through lack of interest. Anyone wanting to go would have to make their own way. So it was just the two of us, from British Gas, at Roosecote.
It was a visit that sticks in my mind. The plant was in the final stage of commissioning, with work on the NOx suppression system still underway. What really amazed us was that it was just two years since the owners and operators, ex Central Electricity Generating Board men, had gone down to London to sign an agreement, on the spot, with electrical engineering group Brown Boveri to build the plant. This was quite dramatic. It was taking eight years to build and operate a coal-fired power station and God knows how long for nuclear. And, instead of a wall-to-wall control board, the CCGT was run off a laptop.
As we drove away, we could see, from the pall of brown smoke, that the gas turbines really were running. They certainly have need for NOx suppression, I thought.
The accolade of plagiarism
I went away, from Roosecote, not connecting the heat recovery steam generator with combined cycle power. It took me the rest of the 1990s to understand what they were all about.
The easy part is that the HRSG is the bit of a combined cycle where the heat in the gas turbine exhaust is used to raise steam, the steam being used to drive a steam turbine. What took longer to understand was that the HRSG is not like a normal power plant boiler, which raises steam at one very high pressure. They are designed around three separate, high, medium, and low pressure boilers.
Although papers on HRSGs were appearing, there wasn’t anything that explained why they were so different. It was an opportunity for me to give some publicity to the European Technology Development (EDT), a tiny consultancy group I was helping to get going, and I published an article on the company’s website.
In 2005, I was over in the Netherlands, as, inter alia, the EU’s technical expert on combined heat and power (CHP). In one of the leading magazines on the subject, Cogeneration and Onsite Power, I came across an article on HRSGs. I was mystified since the HRSG is not really useful in CHP. I was even more surprised to find that what was printed was my article, under someone else’s name, lifted from the ETD website.
The editor’s apology I got was not exactly grovelling. After some exchanges on the internet, she told me, in effect, I should get a life and move on. I don’t forget, however. The only consolation I have is that what I wrote was good enough to be stolen, so I must have been doing something right.